A process for preparing Nilotinib hydrochloride Form R5 and Form R6 comprises: step a) providing a solution of Nilotinib free base in acetic acid and optionally an organic solvent, step b) adding hydrochloric acid taken in an organic solvent to the solution of step a), then separating Nilotinib hydrochloride Form R5 (step c), and finally drying at about 100° C. to 150° C. to obtain Nilotinib hydrochloride Form R6.

The drug compound having the adopted name "nilotinib hydrochloride" has a chemical name 4-methyl-N-[3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl) phenyl]-3-[[4-(3-pyridinyl)-2-pyrimidinyl]amino]-benzamide monohydrochloride, and is structurally represented by Formula I.

Nilotinib hydrochloride is a kinase inhibitor, approved as nilotinib hydrochloride monohydrate, sold using the trade name Tasigna®, in the form of capsule for the treatment of chronic phase and accelerated phase Philadelphia chromosome positive chronic myelogenous leukemia (CML) in adult patients resistant to or intolerant to prior therapy that included imatinib.
International application publication No. WO2007/015871 A1 describes salts of 4-methyl-N-[3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl)phenyl]-3-[[4-(3-pyridinyl)-2-pyrimidinyl] amino]-benzamide, wherein the salt is a hydrochloride salt, hydrochloride monohydrate, monophosphate salt, diphosphate salt, sulfate salt, methanesulfate salt, ethanesulfonate salt, benzene sulfonate salt, p-toluene sulfonate salt, citrate salt, furmarate salt, malonate salt, malate salt, tartrate salt, etc., their polymorphic forms and process for the preparation thereof. Further, it also discloses the crystalline forms of nilotinib hydrochloride designated as Form A and Form B, process for their preparation and process for the preparation of nilotinib hydrochloride monohydrate.
International application publication No. WO2007/015870 A2 describes substantially pure crystalline forms of nilotinib hydrochloride designated as Form A, Form A′, Form A″, Form B, Form B′, Form SB, Form SB′, Form C, Form C′, Form SC, Form D, Form SE, mixture of Form B and Form D, and amorphous form of Nilotinib hydrochloride. Further, it also discloses substantially pure crystalline forms A and B of Nilotinib free base and substantially pure crystalline forms A and B of Nilotinib sulfate salt.
International application publication No. WO2010/054056 A2 describes polymorphic forms of nilotinib hydrochloride designated as forms T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15 T16, T17, T18, and T19. Further, it also describes solid dispersion of nilotinib hydrochloride in combination with a pharmaceutically suitable excipient.
International application publication No. WO2011/163222 describes polymorphic forms of nilotinib hydrochloride designated as forms T20, T27, T28 and T29.
International application publication No. WO2011/086541 A1 describes a crystalline form of nilotinib hydrochloride monohydrate having an X-ray diffraction pattern comprising peaks at 5.70, 7.56, 9.82, 15.01, 17.31 and 27.68±0.2 degrees 2-theta and process for its preparation.
International application publication No. WO2012/055351 A1 describes a crystalline form of nilotinib hydrochloride monohydrate having an X-ray diffraction pattern comprising peaks at 4.987, 8.430, 11.309, 14.403, 17.219, 19.225 and 25.544 degrees 2-theta and process for its preparation.
International application publication No. WO2012/070062 A2 describes nilotinib hydrochloride crystalline form H1, characterized by peaks in the powder x-ray diffraction spectrum having 2-theta angle positions at about 8.6, 11.4, 13.2, 14.3, 15.5, 17.3, 19.2 and 25.3±0.2 degrees and process for its preparation.
US application publication No. 2013/0210847 A1 describes nilotinib hydrochloride dihydrate, characterized by peaks in the powder X-ray diffraction pattern at 4.3, 8.7, 9.5, 11.3, 13.2, 14.4, 17.3, 18.6, 19.3, 20.8, 22.2 and 25.3 degrees 2-theta (±0.1 degrees 2-theta).
IP.com Journal (2010), 10(3B), 11 describes the crystalline forms T24, T25, and T26 of nilotinib hydrochloride and process for their preparation.
IP com Journal (2010), 10(12A), 18 describes the crystalline forms of nilotinib hydrochloride designated as Forms T19 and T20 and process for their preparation.
IP.com Journal (2009), 9(12B), 14 describes the nilotinib hydrochloride crystalline forms T2-T6, T9 and T11-T13 and process for their preparation.
IP.com Journal (2010), 10(5A), 25 describes the nilotinib hydrochloride crystalline form T5 and process for its preparation.
IP.com Journal (2010), 10(7B), 3 describes a method for the preparation of the 4-methyl-N-[3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl)phenyl]-3-[[4-(3-pyridinyl)-2-pyrimidinyl]amino]benzamide salts in amorphous form.
The discovery of new polymorphic forms and/or solvates of a drug or a pharmaceutically useful compound provide opportunity to improve the characteristics of a pharmaceutically acceptable dosage form of the drug with a targeted release profile or other desired characteristics.
The international publication number WO2014/174456A2 discloses the forms R5 and R6 of nilotinib hydrochloride.

Process for the preparation of polymorphic forms of nilotinib hydrochloride


An improved pseudo-random number generator is introduced that has increased security due to higher randomness and lower predictability. The PRNG uses seed values that are based on a combination of various selectable values from the real-world that are typically made publicly available over a computer network (i.e., the Internet), such as: one or more weather conditions at a particular time or date and geographic location, a score of a sports event, a stock market index or ticker value, an election vote total, attendance at a cultural event, gross dollar sales from a movie release, and other such numerically quantifiable values that, individually and in combination, are impossible to exactly predict in advance, yet are precisely verifiable after the number-generating event using electronically-stored information. The improved pseudo-random number generator may be used for more secure determination of lottery outcomes and the like.

Random number generation has many applications in computing technology, as well as in the sciences and useful arts. Randomness is, in fact, crucial to cryptography, network security, online gaming and gambling, statistics and statistical analysis, mathematical systems modeling and many other fields. For example, in controlled medical trials, random assignment of treatments eliminates possible biases when testing treatment efficacies. Computerized generation of random or pseudo-random numbers are also required to simulate real world events in applications such as video games, as well as gaming machines like video blackjack.
Mathematically, there are well-known distinctions between randomization, pseudo-randomization, and quasi-randomization, as well as between pure random number generators (RNGs) and pseudo-random number generators (PRNGs). While hardware-based RNGs can reliably generate numerical sequences that are close to truly random, software-based PRNGs are more ubiquitous because of their speed and reproducibility. Nevertheless, such PRNGs are not truly random, because the numerical sequences are typically generated from a relatively small set of initial values, called seed values. Thus, PRNGs are susceptible to becoming more predictable when, for example, brute-force attacks or the like are surreptitiously used to determine underlying seed values.
PRNGs, also known as a deterministic random bit generators (DRBGs), comprise various algorithms, executed in software, for generating a sequence of numbers whose properties approximate the properties of sequences of truly randomized numbers. However, the requirements for randomness and predictability vary for different application. For example, applications in cryptography usually have strict high-randomness and low-predictability requirements, whereas other uses, such as generating a PRNG for determining outcomes in a children's video game, can use a looser standard of pseudo-randomness.
A PRNG suitable for cryptographic applications is called a Cryptographically Secure PRNG (CSPRNG). A requirement for a CSPRNG is that an attacker, not knowing the seed values, has only negligible advantage in distinguishing the generator's output sequence from a random sequence. In other words, while a PRNG is only required to pass certain statistical tests, a CSPRNG must pass stringent statistical tests in relation to the size of the seed(s). Existing PRNGs that have been designed specifically to be cryptographically secure include: MICROSOFT'S CRYPTOGRAPHIC APPLICATION PROGRAMMING INTERFACE function "CryptGenRandom," MAC OSX operating systems, UNIX systems incorporating FREEBSD, and LINUX systems incorporating FORTUNA.
Accordingly, as computing power continues to increase, there is a continuing need for improved methods and systems for pseudo-random number generation, which are easily implemented and effective to secure computer systems and the applications requiring randomization functions.

This patent is subject to a terminal disclaimer.

Methods and systems for improved pseudo-random number generation


A receiving surface (625) for use in the supersonic welding of the welding boss (620) of an M cassette tape reel (612a) is composed of the lower surface of a ring portion (626) which is formed so as to extend annularly along the base end of a hub central portion (621) formed in the bottom surface (616a) of a lower reel (616) and also which is projected downward (in FIG. 2) by a given amount from the bottom surface (616a). That is, the receiving surface (625) is situated slightly outside in the radial direction from directly below the welding boss (620).

The present invention relates to a tape reel for use in a magnetic tape cassette such as a digital video cassette (DVC). In particular, the present invention relates to a structure for improving a supersonically welding of a welding boss of a tape reel, a structure for improving the winding shape of a magnetic tape to be wound around a tape reel, a structure for securing the dustproof property of a magnetic tape cassette when not in use as well as preventing the deformation of a lower flange of a tape reel, a structure for preventing a magnetic tape from being damaged due to its contact with a tape reel, and a structure having a characteristic hub.
Also, the invention relates to a magnetic tape take-up device for winding a magnetic tape around a tape reel and, in particular, to a structure for fixing the winding shape of a magnetic tape with the inner surface of an upper flange of a tape reel as a reference.
Generally, in audio equipment and video equipment, there is often used a magnetic tape cassette structured such that a magnetic tape wound around a pair of tape reels is runnably held within a cassette half to thereby execute recording and reproduction.
Referring now to FIG. 20, conventionally, for example, as a magnetic tape cassette which is used as a DVC (digital video cassette), there is known a magnetic tape cassette 130 in which a pair of tape reels 131 with a magnetic tape t wound therearound are rotatably supported within a lower cassette half 133 making a pair with an upper cassette half 132.
On both sides of an opening 134 formed on this side in FIG. 20 of the lower cassette half 133, there are disposed tape guides 135 respectively. The two tape guides 135 respectively guide the magnetic tape t which is fed out from one tape reel 131 and is taken up around the other tape reel 131, and allow the magnetic tape t to pass through a given position in the opening 134.
Also, on the rear side of the lower cassette half 133, there is disposed a reel lock member 139 having a tape reel securing arm 138. The reel lock member 139 is energized by a compression coil spring 140 to bring the tape reel securing arm 138 into engagement with two engaging teeth 141 respectively formed on the outer peripheries of the two tape reels 131, thereby preventing the unprepared rotation of the respective tape reels 131. This can prevent the wound magnetic tape t from loosening.
On the upper cassette half 132, there are mounted an outer lid 150 for covering the opening 134 of the lower cassette half 133, an upper lid 151 and an inner lid 152 in such a manner that they can be freely opened and closed.
On the two side plates 153 of the outer lid 150, there are projectingly provided lock pins 154, respectively. The two lock pins 154 are respectively secured to their associated lid locks 155 which are rotatably disposed on the lower cassette half 133. By the way, reference character 156 designates a lid spring to be mounted on the rotary shaft of the outer lid 150.
The tape reels 131 are respectively structured such that mutually opposing upper and lower flanges 142 and 143 are fixed with a given position relationship between them.
That is, in each tape reel 131, a pivot 147 projectingly provided on a hub 145 of the lower flange 143 is fitted into a pivot hole 146 formed in the central portion 144 of the upper flange 143. Also, a welding boss 148, which is provided on and projected from the hub 145 of the lower flange 143 at a position distant in the radial direction from the pivot 147, is fitted into a welding boss hole 149 formed in the central portion 144 of the upper flange 142 at a position corresponding to the welding boss 148. In this state, in case where a welding horn (not shown) is contacted with the substantially central portion of the leading end face (in FIG. 20, the upper end face) of the welding boss 148, the welding boss 148 can be welded supersonically. As a result of this, the mutually opposed upper and lower flanges 142 and 143 can be fixed with a given position relationship between them.
Now, referring to FIGS. 20 and 21, on the bottom surface 143a of the lower flange 143 that is situated on the opposite side of the hub 145, there is disposed a reference ring 157 which provides a reference for working using a metal mold. The reference ring 157 is present at a position which is more distant in the radial direction than the welding boss 148. The surface 157a of the reference ring 157 is used as a receiving surface for receiving the welding boss 148 when it is welded supersonically, because the surface 157a makes it possible to facilitate the grasping of the dimensional relationship. That is, in case where the surface 157a of the reference ring 157 is contacted with a welding receiving base (not shown) when the welding boss 148 is welded supersonically, the surface 157a allows the welding receiving base to receive pressures applied from the welding horns and vibrations caused by the supersonic oscillation.
In the above-mentioned conventional magnetic tape cassette 130, the surface 157a of the reference ring 157 is used as the receiving surface when the welding boss 148 is supersonically welded. Due to this, the oscillation energy of the supersonic waves from the welding horns is in part lost due to the resonance of the components of the tape reel 131 existing from the welding boss 148 to the reference ring 157, resulting in the low transmission efficiency of the oscillation energy of the supersonic waves from the welding horn to the welding boss 148. In case where the transmission efficiency of the oscillation energy of the supersonic waves is low, it takes time to weld the welding boss 148, which makes it necessary to extend the oscillation time of the supersonic waves, resulting in the poor mass-production aptitude and in the poor welding stability. Further, in case where the welding stability is poor, there is a fear that the mutually opposing attitudes of the upper and lower flanges 142 and 143 can be out of balance, giving rise to the vibratory motion of the surfaces of the tape reel 131 when it is rotated.
It is a first object of the invention to provide a tape reel for use in a magnetic tape cassette which can enhance the transmission efficiency of the oscillation energy of the supersonic waves to the welding boss to thereby be able to shorten the time necessary for supersonic welding of the welding boss as well as to enhance the welding stability.
Next, referring to FIG. 22, the inner surface (lower surface) of the upper flange 142 is formed as a sloping surface 142b which gradually slopes upward from the base end portion (in FIG. 22, the upper end portion a) of the side wall 145b of the hub 145 toward the radial-direction outer side (in FIG. 22, the right side) of the upper flange 142. Also, the inner surface (upper surface) of the lower flange 143 is formed as a sloping surface 143b which gradually slopes downward from the base end portion (in FIG. 22, the lower end portion b) of the side wall 145b of the hub 145 toward the radial-direction outer side (in FIG. 22, the right side) of the lower flange 143.
However, in case where such slopes are formed on the whole areas of the lower surface of the upper flange and the lower surface of the lower flange, it is true that, when the magnetic tape is wound, it can be wound easily; but, there is also a fear that the magnetic tape can be vibrated in the vertical direction.
In case where a given period of time passes after the winding operation of them magnetic tape is started, the rotation speed of the reel drive means and the tape tension become constant, so that the magnetic tape runs stably and thus there is no fear that it can be vibrated in the vertical direction. However, at the beginning of the winding operation of the magnetic tape, the rotation speed of the reel drive means increases gradually and the tape tension also increases, so that the magnetic tape is not be able to run stably.
In this case, since the magnetic tape is vibrated in the vertical direction, the side edges of the wound magnetic tape cannot be superimposed on each other in a well-arranged manner, so that the wound surface of the magnetic tape to be formed by the side edges of the magnetic tape can be out of order and thus it cannot provide a flat surface; that is, there arises a problem that the magnetic tape cannot have a fine winding shape.
Accordingly, it is a second object of the invention to solve the above problem: that is, it is a second object of the invention to provide a magnetic tape reel which allows a magnetic tape to provide a fine winding shape after it is wound.
Next, referring to FIG. 23, on the edge portions of reel holes 133a formed in the inner surface (in FIG. 23, the upper surface) of the lower cassette half 133, there are provided annular-shaped projecting portions 133b, respectively. These annular-shaped projecting portions 133b, when the magnetic tape cassette 130 is not in use (that is, in the state thereof shown in FIG. 23), are respectively contacted with the outer surfaces of the lower flanges 141 of the respective tape reels 131. Due to this, the annular-shaped projecting portions 133b are respectively able not only to prevent entry of dust into the interior of the magnetic tape cassette 130 as much as possible but also to support the weights of the respective tape reels 131 and the weight of the magnetic tape t wound around the respective tape reels 131.
In the above-mentioned magnetic tape cassette 130, in case where the respective tape reels 131 increase in size (outside diameter), when the magnetic tape cassette 130 is not in use, the lower flanges 141 of the respective tape reels 131 are not be able to support the weight of the magnetic tape t, thereby raising a problem that the portions of the lower flanges 141, which are present outside the contact portions of the lower flanges 141 with their associated annular-shaped projecting portions 53b, can be flexed.
In this case, in case where the thicknesses of the lower flanges 141 of the respective tape reels 131 are increased, the above problem can be solved. However, in case where the thicknesses of the lower flanges 141 increase, there arises another problem that there cannot be secured a clearance between the lower flanges 141 and lower cassette half 133 when the magnetic tape cassette 130 is not in use. In case where such clearance cannot be secured, for example, there arises an inconvenience that, due to the vibrations of the magnetic tape cassette half 130 when it is delivered, the lower flanges 141 and lower cassette half 133 are slidingly contacted with each other.
Accordingly, it is a third object of the invention to provide a magnetic tape cassette which can secure a high dust-proof condition in the interior thereof when it is not in use, can positively prevent the lower flanges of the tape reels against deformation, and can secure a sufficient clearance between the lower flanges and a lower cassette half.
Next, referring to FIG. 24, conventionally, as a magnetic tape cassette for a beta cam, for example, there is known a magnetic tape cassette 230 in which a pair of tape reels 231 with a magnetic tape t wound therearound are rotatably supported within a lower cassette half 233 which makes a pair with an upper cassette half 232.
On the two sides of an opening 234 formed on this side in FIG. 24 of the lower cassette half 233, there are disposed tape guides 235 respectively. The tape guides 235 respectively guide the magnetic tape t, which is fed out from one tape reel 231 and is then taken up around the other tape reel 231, and allows the magnetic tape t to pass through a given position in the opening 234. On the other hand, on the upper cassette half 232, there is openably and closably mounted a lid 250 which covers the opening 234 of the lower cassette half 233.
The tape reels 231 are respectively structured such that, with a given clearance formed between the mutually opposed upper and lower flanges 242 and 243, the central portion 244 of the upper flange 242 and the hub 245 of the lower flange 243.
That is, in each of the tape reels 231, a pivot 247 provided on the hub 245 of the lower flange 243 is fitted into a pivot hole 246 formed in the central portion 244 of the upper flange 242. Also, a plurality of welding bosses 248, which are provided on and projected from the hub 245 of the lower flange 243 at positions spaced from the pivot 247 in the radial direction of the hub 245, are respectively fitted into a plurality of welding boss holes 249 formed in the central portion 244 of the upper flange 242 at positions corresponding to the welding bosses 248.
In this state, in case where welding horns (not shown) are respectively contacted with the substantially central portions of the leading end faces of the respective welding bosses 248, the welding bosses 248 can be welded supersonically. As a result of this, the mutually opposed upper and lower flanges 242 and 243 can be fixed with a given clearance between them.
Referring here to FIG. 25, when the lower flange 243 is molded using a metal mold, in the surface 243a (in FIG. 25, the upper surface) of the lower flange 243 that is disposed opposed to the upper flange 242, there are formed a plurality of air discharging recessed portions 251 (in FIG. 24, not shown) which are spaced at given intervals in the peripheral direction of the opposed surface 243a. The respective air discharging recessed portions 251 discharge the air, which enters the interior of the tape reel together with the magnetic tape t when the magnetic tape t is taken up around the tape reel, externally of the tape reel to thereby prevent the magnetic tape t from being wound in disorder.
In the above-mentioned conventional magnetic tape cassette 230 for a beta cam, substantially over the entire periphery of the edge portions 252 of the air discharging recessed portions 251 of the lower flanges 243, there are generated edges 253 when the magnetic tape cassette 230 is molded using a metal mold. This raises a problem that, when the magnetic tape t is taken up around the tape reel, the edges 253 can be contacted with the magnetic tape t, thereby causing the magnetic tape t to be damaged.
This problem, recently, with the enhanced density of the magnetic tape recording, has a seriously ill effect on the recording accuracy and, especially, in a magnetic tape cassette for business such as a beta cam, this problem is serious.
Accordingly, it is a fourth object of the invention to provide a magnetic tape cassette which can prevent a magnetic tape against damage due to its contact with a tape reel to thereby be able to cope with the enhanced density of the magnetic tape recording.
Also, in the case of a tape reel of the above-mentioned type, since the height of the hub thereof is slightly larger than the width of a magnetic tape, while the magnetic tape is being wound around the tape reel, the magnetic tape can be moved up and down when it is moved in the axial direction of the hub, with the result that the magnetic tape wound around the hub of the tape reel can be projected in part in the axial direction of the hub. In order to prevent this, in JP-A-58-187083U, there is disclosed a tape reel structured such that the peripheral surface of the hub thereof is inclined with respect to the axial direction of the hub. Here, FIG. 26(a) is a section view of the tape reel set forth in the above-cited publication, and FIG. 26(b) is a schematic side view of the hub of the present tape reel.
Specifically, in the conventional tape reel shown in FIG. 26, on the upper and lower surfaces of a hub 320, there are disposed upper and lower flanges 322 and 324; the hub 320 and lower flange 324 are formed of resin as an integral body; and, the central portion of the resin-made upper flange 322, which is produced separately from the hub 320, is supersonically welded to the upper end of the hub 320. Although the outer peripheral surface 320a of the hub 320 is circular, the center line A of the circular-shaped outer peripheral surface 320a is inclined by a given angle xcex8 with respect to the axial direction B of the hub 320. Also, the mutually opposed inner surfaces 322a and 324a of the upper and lower flanges 322 and 324 are respectively formed as sloping surfaces which spread out as they go outwardly in the radial direction thereof. The peripheral surfaces of the hub 320 are inclined over the entire areas thereof; and, the peripheral surfaces of the hub 320, which are disposed 180xc2x0 opposed to each other when the hub 320 is viewed from the top plan thereof, are inclined in different directions in the axial direction of the hub 320.
According to the above tape reel, since a magnetic tape 326 to be wound around the hub 320 is contacted with either o f the upper flange 322 or lower flange 324 at each angle of 180xc2x0 when the hub 320 is viewed from the top plan thereof and is thereby restricted in the vertical movement thereof, the magnetic tape 326 can be wound around the hub 320 without being projected in part in the axial direction B of the hub 320.
By the way, generally, the pulling direction of a molding, that is, a molded hub from a metal mold is equal to the axial direction of the hub. However, in the case of the hub 320 shown in FIG. 26 in which the peripheral surfaces of the hub 320 disposed 180xc2x0 opposed to each other when the hub 320 is viewed from the top plan thereof slope in different directions in the axial direction of the hub 320, after it is injection molded, it cannot be pulled out from the metal mold along the axial direction B thereof as it is. For this reason, to manufacture the hub 320, there is necessary a metal mold using a slide core, which not only complicates the structure of a metal mold but also makes it difficult to manufacture the hub 320.
Accordingly, it is a fifth object of the invention to solve the above problem; in particular, to provide a magnetic reel which is easy to manufacture and around which a magnetic tape can be wound with a good winding shape, and a method for manufacturing such tape reel.
Next, as a magnetic tape take-up apparatus, conventionally, in Japanese Patent Unexamined Publication No. Hei.1-217782, there is disclosed a magnetic tape take-up apparatus 440 structured such that, as shown in FIG. 27, a magnetic tape 444 being wound around a tape reel 441 is energized in the direction of a lower flange 442 not in contact with the lower flange 442 by a permanent magnet 443 disposed opposed to the lower flange 442 of the tape reel 441 to thereby arrange the winding shape of the magnetic tape 444 with the inner surface of the lower flange 442 as a reference surface.
The tape reel 441 is mounted on the rotary shaft 446 of a drive mechanism 445 and, in case where the tape reel 441 is driven or rotated by the drive mechanism 445, it takes up the magnetic tape 444 from a tape supply source onto a tape winding surface 447. The permanent magnet 443 is formed in a doughnut shape; and, with the rotary shaft 446 of the drive mechanism 445 loosely fitted into a through hole 448, the permanent magnet 443 is supported through a support portion 449 on a take-up apparatus main body 450.
In the above-mentioned conventional magnetic tape take-up apparatus 440, the permanent magnet 443 is disposed opposed to the lower flange 442 of the tape reel 441 and is used to arrange the winding shape of the magnetic tape 444 with the inner surface of the lower flange 442 as a reference surface.
Therefore, there arises a problem that, when a magnetic tape cassette is set on a recording and reproducing apparatus and the magnetic tape 444 is then made to run, the running passage of the magnetic tape 444, through which it is made to run for the first time by the recording and reproducing apparatus, is shifted from the running passages thereof through which it is made to run for the second time and following times.
That is, for example, in such a recording and reproducing apparatus 460 as shown in FIG. 28, in the first tape running, a magnetic tape 462, which is wound around a tape reel 461 by the conventional magnetic tape take-up apparatus 440, runs through a passage which is shifted to the lower side in FIG. 28 as shown by a two-dot chained line shown in FIG. 28. The reason for this is as follows: that is, since the lower flange of the tape reel 461 has a taper surface sloping downward toward the radial direction of the tape reel 461, the magnetic tape 462 wound around the tape reel 461 is caused to lower downward gradually toward its outer periphery side. In the second and following tape runnings in which the magnetic tape 462 rewound around the tape reel 461 by the magnetic tape take-up apparatus 440 is made to run again, the magnetic tape 462 runs through its normal running passage which is shown by a solid line in FIG. 28. Thus, the running passage of the magnetic tape is shifted between the first tape running and the second and following tape runnings by the recording and reproducing apparatus 460.
Now, description will be given below in detail of the cause of the shifted running passage of the magnetic tape 462.
Firstly, referring to the running passage of the magnetic tape 462 in the magnetic tape take-up apparatus 440, the magnetic tape 462, which is played out from the tape reel 461 of the magnetic tape cassette 463, is guided by tape guides TG0, TG1, TG2 and TG3. This defines the mutually relative positions of the magnetic tape 462 and a recording and reproducing head 464 (cylinder).
In other words, the magnetic tape 462 drawn out from the tape reel 461 is once raised up to its upper limit position by the tape guide TG1 through the tape guide TG0 and the position of the magnetic tape 462 at the upper limit position is controlled by the tape guide TG1; and, after then, the position of the magnetic tape 462 is controlled to its original position between the tape guides TG2 and TG3, and the magnetic tape 462 is then contacted with the recording and reproducing head 464 at a given relative position.
However, in case where the magnetic tape 462 is wound around the tape reel 461 by the conventional magnetic tape take-up apparatus 440, since the lower flange has a taper surface, the play-out position of the magnetic tape 462 from the tape reel 461 is a low position (a position which near to the lower flange 466) shown by a two-dot chained line in FIG. 28.
Due to this, the magnetic tape 462 drawn out from the tape reel 461, as shown by the two-dot chained line in FIG. 28, is not be able to reach the upper limit position to which it ought to be guided by the tape guide TG1; and, therefore, without being controlled in position at the upper limit position by the tape guide TG1, the magnetic tape 462 is controlled in position by the tape guides TG2 and TG3. As a result of this, the running passage of the magnetic tape 462 between the tape guides TG2 and TG3 is shifted from its normal or original running passage. This phenomenon occurs more outstandingly as the magnetic tape 462 wound is present on the outer periphery side.
In case where, as described above, the running passage of the magnetic tape 462 is shifted between the first tape running and the second and following tape runnings by the recording and reproducing apparatus 460, the relative positions of the magnetic tape 462 and recording and reproducing head 464 in the first tape running is different from the relative positions of the magnetic tape 462 and recording and reproducing head 464 in the second and following tape runnings. As a result of this, there arises a problem that, in the recording and reproducing states of the magnetic tape 462, there occurs a serious fault, such as poor interchangeability which cannot be repaired.
Accordingly, it is a sixth object of the invention to provide a magnetic tape take-up apparatus which can arrange the winding shape of a magnetic tape with the upper flange of a tape reel as a reference to thereby be able to stabilize the running of the magnetic tape in a recording and reproducing apparatus.
In attaining the above-mentioned first object, according to a first invention, there is provided a tape reel for use in a magnetic tape cassette, comprising: an upper flange; and, a lower flange disposed opposed to the upper flange and including a hub on the surface thereof opposed to the central portion of the upper flange, wherein a pivot provided on and projected from the hub is fitted into a pivot hole formed in the central portion of the upper flange, a welding boss projectingly disposed at a position of the hub distant from the pivot in the radial direction of the hub is fitted into a welding boss hole formed in the central portion of the upper flange, and, in this state, the welding boss is welded supersonically, whereby the upper and lower flanges are fixed with a given position relationship between them, characterized in that, on the opposite surface of the lower flange to the hub, there are disposed not only a reference ring which is used as a reference for working the tape reel using a metal mold but also, radially inside the reference ring, a receiving surface for use in the supersonic welding of the welding boss.
In the tape reel for use in a magnetic tape cassette according to the first invention, the pivot projectingly provided on the hub formed integral with the lower flange is fitted into the pivot hole formed in the central portion of the upper flange. Also, the welding boss projectingly disposed at a position of the hub distant from the pivot in the radial direction of the hub is fitted into the welding boss hole formed in the central portion of the upper flange. In this state, the welding boss is welded supersonically. Due to this, the upper and lower flanges are fixed with a given position relationship between them.
On the opposite surface of the lower flange to the hub, there is disposed the reference ring which is used as a reference for working the tape reel using a metal mold and, in the portion of the opposite surface of the lower flange to the hub that is situated internally of the reference ring in the radial direction of the tape reel, there is formed the receiving surface for use in the supersonic welding of the welding boss.
In case where the receiving surface, in the supersonic welding of the welding boss, is contacted, for example, with a welding receiving base, the welding boss allows the welding receiving base to receive not only pressures applied from welding horns but also vibrations caused by the oscillation of the supersonic waves. In this case, since the receiving surface is situated in the portion of the opposite surface of the lower flange to the hub that is situated internally of the reference ring in the radial direction of the tape reel, the oscillation energy of the supersonic waves from the welding horns can be prevented from being lost by the resonance of the components disposed from the welding boss to the reference ring.
Also, in attaining the above second object, according to a second invention, there is provided a magnetic tape reel, comprising: a hub for winding a magnetic tape therearound; and, upper and lower flanges respectively positioned on the upper and lower ends of the hub, each of the inner surfaces of the upper and lower flanges being formed so as to slope outwardly in the radial direction of the magnetic tape reel, wherein, on the adjacent portions of the upper and lower flanges to the hub, there are respectively formed flat surfaces lying at right angles to the side surface of the hub and having a given width in the radial direction of the magnetic tape reel.
The radial-direction width of each of the flat surfaces may be preferably larger than the tape winding thickness obtained before, in the tape take-up operation, the motor speed or the tape tensile force becomes constant from the beginning of the tape take-up operation, that is, before the tape take-up ability becomes constant. Specifically, for example, in the case of the above-mentioned DVC, for all sizes of S, M, L, the radial-direction width of the flat surface may be larger than the thickness of a clamp for fixing a tape to the hub, in more specifically, the width may be preferably set in the range of 0.5-5.0 mm.
Also, the clearance between the upper and lower flat surfaces may be set slightly larger than the width of the magnetic tape and may be set as narrowly as possible so long as it does not provide any obstacle to the running of the magnetic tape.
According to the second invention, the portions of the flanges existing in the periphery of the hub do not slope but the flanges are parallel to each other and, in the beginning of the winding operation of the magnetic tape, there is no room for the magnetic tape to move up and down; and, therefore, the winding surface of the magnetic tape consisting of the side edges of the magnetic tape is arranged uniformly, thereby allowing the magnetic tape wound to have a good winding shape.
Also, in attaining the above third object, according to a third invention, there is provided a magnetic tape cassette, comprising: a tape reel including upper and lower flanges, the upper and lower flanges being disposed opposed to each other and fixed with a given position relationship between them; an upper cassette half; and, a lower cassette half disposed opposed to the upper cassette half, the lower cassette half being capable of storing the tape reel in an internal space formed between the upper cassette half and itself, the lower cassette half including a reel hole for insertion and removal of tape reel drive means, wherein the lower flange of the tape reel includes a large-thickness stepped portion formed so as to be continuous with an outside annular-shaped rib, while the portion of the large-thickness stepped portion opposed to the edge portion of the reel hole of the lower cassette half has a thickness set at a given value or more.
Also, in attaining the above third object, according to a fourth invention, there is provided a magnetic tape cassette, comprising: a tape reel including upper and lower flanges, the upper and lower flanges being disposed opposed to each other and fixed with a given position relationship between them; an upper cassette half; and; a lower cassette half disposed opposed to the upper cassette half, the lower cassette half being capable of storing the tape reel in an internal space formed between the upper cassette half and itself, the lower cassette half including a reel hole for insertion and removal of tape reel drive means, wherein, on the edge portion of the reel hole formed in the inner surface of the lower cassette half, there is disposed an annular-shaped projecting portion and, on the radial-direction outside of the annular-shaped projecting portion, there is formed an annular-shaped recessed portion, and, also wherein, in a position which is present in the outer surface of the lower flange of the tape reel and is opposed to the annular-shaped recessed portion, there is disposed an annular-shaped projection to be loosely fitted into the annular-shaped recessed portion.
In the magnetic tape cassette according to the third invention, when the present magnetic tape cassette is not in use, the large-thickness stepped portion formed so as to be continuous with an outside annular-shaped rib, with the portion thereof opposed to the edge portion of the reel hole of the lower cassette half having a thickness set at a given value or more, is contacted with the edge portion of the reel hole of the lower cassette half.
In this state, entry of dust into the interior of the magnetic tape cassette can be prevented and thus a highly dust-proof effect can be secured.
Also, tape reels and a magnetic tape wound around the tape reels are supported on the lower cassette half through the large-thickness stepped portions of the lower flanges of the tape reels with the portions thereof having a thickness set at a given value or more. Not only due to such support of the tape reels through the large-thickness stepped portions of the lower flanges formed continuous with the outside annular-shaped ribs and having a thickness set at a given value or more but also due to the enhanced rigidity of the lower flanges of the tape reels by the portions of the lower flanges having a thickness set at a given value or more, even in a tape reel having a large diameter, deformation of the lower flange of the tape reel due to the weight of the magnetic tape can be prevented positively. Thanks to this, when the magnetic tape cassette is not in use, there can be secured a sufficient clearance between the lower flanges of the tape reels and lower cassette half.
In the magnetic tape cassette according to the fourth invention, when the present magnetic tape cassette is not in use, the annular-shaped projecting portion of the lower half cassette is contacted with the outer surfaces of the lower flanges of the tape reels, and the annular-shaped projections of the lower flanges are loosely fitted into the annular-shaped recessed portion of the lower cassette half and are thereby contacted with the lower cassette half.
In this state, entry of dust into the interior of the magnetic tape cassette can be prevented and thus a highly dust-proof effect can be secured.
Also, tape reels and a magnetic tape wound around the tape reels are supported on the lower cassette half through the annular-shaped projecting portion of the lower cassette half and the annular-shaped projections of the lower flanges. Due to support of the tape reels through the annular-shaped projecting portion of the lower cassette half and the annular-shaped projections of the lower flanges, even in a tape reel having a large diameter, deformation of the lower flange of the tape reel due to the weight of the magnetic tape can be prevented positively. Thanks to this, when the magnetic tape cassette is not in use, there can be secured a sufficient clearance between the lower flanges of the tape reels and lower cassette half.
And, in attaining the above fourth object, according to a fifth invention, there is provided a magnetic tape cassette including a tape reel, the tape reel comprising: an upper flange; and, a lower flange disposed opposed to the upper flange and fixed with a given position relationship with respect to the upper flange, the lower flange including a hub providing a winding surface for winding a magnetic tape therearound, wherein, in the surface of the upper flange that is opposed to the lower flange, or, in the surface of the lower flange that is opposed to the upper flange, there is formed an air discharging recessed portion or an air discharging penetration hole for discharging out the air entering together with a magnetic tape when the magnetic tape is wound around the reel, and, also wherein the edge portions of two sides of the air discharging recessed portion or the air discharging penetration hole in at least radial direction of the flanges are formed into a curve-shape respectively.
In the magnetic tape cassette according to the fifth invention, when the magnetic tape is taken up around the tape reel, the air discharging recessed portion or air discharging penetration hole functions as a flow passage for discharging the accompanying air, thereby being able to prevent the magnetic tape from being wound in disorder. In this case, even when the magnetic tape is contacted with the edge portion of the air discharging recessed portion of the tape reel, the required curved shape applied to the edge portion can prevent the magnetic tape against damage.
Also, in attaining the above fifth object, according to a sixth invention, there is provided a magnetic tape reel, wherein the outer surface of a clamp member for holding a leader tape between itself and a recessed portion formed in a hub for winding a magnetic tape therearound and the peripheral surface of the hub that, when viewed from the top plan surface of the hub, is disposed 180xc2x0 opposed to the recessed portion are respectively taper surfaces which slope in mutually different directions in the axial direction of the magnetic tape reel.
Further, in attaining the above fifth object, according to a seventh invention, there is provided a method for manufacturing a magnetic tape reel having a structure that, in a hub for winding a magnetic tape therearound, there is formed a recessed portion for holding a leader tape using a clamp member, and the peripheral surface of the hub that, when viewed from the top plan surface of the hub, is disposed 180xc2x0 opposed to the recessed portion is a taper surface sloping toward the axial direction of the hub, the method comprising the steps of: injection molding the magnetic tape reel; and, pulling out the injection molded magnetic tape reel along the axial direction thereof.
According to the sixth and seventh inventions, the hub includes the sloping peripheral surface only on one side thereof and the recessed portion of the hub, which is formed on the opposite side of the sloping peripheral surface and into which the clamp member can be fitted, does not have any gradient. Therefore, after the magnetic tape reel is molded, the hub, as it is, can be pulled out along the axial direction of the magnetic tape reel. This does not require a complicated metal mold using a slide core and thus the hub can be manufactured easily using a metal mold having a simple structure.
Also, in the case of the clamp member, there is formed a sloping surface on the peripheral surface thereof but, after it is injection molded, it can be pulled out along the axial direction thereof as it is. Therefore, also when manufacturing the clamp member, there is not required a complicated metal mold using a slide core and thus the clamp member can be manufactured easily using a metal mold having a simple structure.
Further, in attaining the above sixth object, according to an eighth invention, there is provided a magnetic tape take-up apparatus, comprising: drive means for rotating a tape reel to thereby wind a magnetic tape around the tape reel at a winding speed of 2-2.5 m/s and with a winding tension of 60-70 g; and, magnetic field generating means including a magnet formed of neodymium and having a magnetic flux density of 12800-13300 G, and disposed opposed to the upper flange of the tape reel with a clearance of 12-17 mm between them for applying a magnetic field to the magnetic tape from the upper flange side of the tape reel.
The area of the portion of the magnetic field generating means opposed to the upper flange of the tape reel may be preferably 1.3 times or more the area of the side surface side of the magnetic tape to be wound around the tape reel.
In the magnetic tape take-up apparatus according to the eighth invention, the drive means rotates the tape reel to thereby wind a magnetic tape from a tape supply source around the tape reel at a winding speed of 2-2.5 m/s and with a winding tension of 60-70 g. Also, the magnetic field generating means including a magnet formed of neodymium and having a magnetic flux density of 12800-13300 G applies a magnetic field to the magnetic tape from a position where it is opposed to the upper flange of the tape reel with a clearance of 12-17 mm between them. Due to this, the magnetic field given by the magnetic field generating means can be applied uniformly to the magnetic tape from the upper flange side of the tape reel.
In the magnetic tape take-up apparatus according to the eighth invention, the area of the portion of the magnetic field generating means opposed to the upper flange of the tape reel, preferably, may be set 1.3 times or more the area of the side surface side of the magnetic tape to be wound around the tape reel.

Tape reel for use in magnetic tape cassette


A junction for the intersection of a main borehole and a lateral borehole includes a main tubular having a main window with a ramp aligned with the main window and a lateral tubular adapted to be telescopingly received within the main tubular and having a lateral window. The main tubular and lateral tubular each have an orientation surface. The lateral tubular has a first position with one end partially disposed within the main tubular. The lateral tubular is telescoped into the main tubular with the end of the lateral tubular engaging the ramp which guides the end of the lateral tubular through the main window and into the lateral bore. The orientation surfaces engage to orient the lateral window with the main window and form a common opening between the tubulars.

1. Field of the Invention
The present invention relates generally to a method and apparatus for the completion of multilateral wells, that is, when one or more lateral wells are drilled from a primary well bore, and more particularly to a new and improved method and apparatus for a junction between the primary well bore and a lateral well bore.
2. Background of the Invention
Multiple lateral bores are typically drilled and extended from a primary or main well bore. The main well bore can be vertical, deviated, or horizontal. Multilateral technology can be applied to both new and existing wells, and provides operators several benefits and economic advantages over drilling entirely new wells from the surface. For example, multilateral technology can allow isolated pockets of hydrocarbons, which might otherwise be left in the ground, to be tapped. In addition, multilateral technology allows the improvement of reservoir production, increases the volume of recoverable reserves, and enhances the economics of marginal pay zones. By using multilateral technology, multiple reservoirs can be produced simultaneously, thus facilitating heavy oil production. Thin production intervals that might be uneconomical to produce alone become economical when produced together with multilateral technology. Consequently, it has become a common practice to drill deviated, and sometimes horizontal, lateral boreholes from a primary wellbore in order to increase production from a well.
In addition to production cost savings, development costs also decrease through the use of existing infrastructure, such as surface equipment and the well bore. Multilateral technology expands platform capabilities where space is limited, and allows more well bores to be added to produce a reservoir without requiring additional drilling and production space on the platform. In addition, by sidetracking depleted formations or completions, the life of existing wells can be extended. Finally, multilateral completions accommodate more wells with fewer footprints, making them ideal for environmentally sensitive or challenging areas.
The primary wellbore may be sidetracked to produce the lateral borehole into another production zone. Further, a lateral wellbore may be sidetracked into a common production zone. In sidetracking, a whipstock and mill assembly is used to create a window in the wall of the casing of a wellbore. The lateral wellbore is then drilled through this window out into the formation where new or additional production can be obtained.
One of the objectives of a multilateral well is containment of the surrounding formation. Production from a lateral borehole can be difficult if the lateral borehole is drilled through a loose or unconsolidated formation. If the lateral borehole is drilled through an unstable or unconsolidated formation, the formation will tend to cave into the borehole. The formation can also slough off, causing deleterious debris to mix with the production fluids. Thus, it is preferred to contain the formation to prevent cave-ins and slough-offs.
Formations that contain a significant amount of shale can be a particular problem. If the bore surfaces at and near the junction are not covered with a liner, chips and aggregate in this area tend to be drawn into the produced fluids and foul the production. Unfortunately, lining the bore surfaces near the junction can be complex and time consuming. Various devices have been proposed to provide a junction at the interface of the primary and lateral wellbores.
There have been attempts to use a perforated insert through the window to allow production from both the primary bore and lateral bore while reducing contamination from chips and aggregate. The perforations are aligned with the primary bore and fluid from the primary bore passes through the perforations. Unfortunately, the perforations tend to become clogged by the chips and aggregate and allow the chips and aggregate to contaminate the product, thereby reducing the effectiveness of this type of insert. Also, the use of a perforated insert hinders the ability to reenter the main bore below the junction.
The junction of the lateral borehole with the primary wellbore is usually ragged and rough as a result of the milling of the window through the casing to drill the lateral borehole. It is particularly difficult to seal around the window which is of a peculiar shape and has a jagged edge around its periphery.
A large area is exposed to the formations when the window is cut in the casing. A tie-back assembly may be disposed adjacent the junction of the lateral borehole and primary wellbore. See for example U.S. Pat. No. 5,680,901. The tieback assembly and liner limit the exposure of the formation through the window cut in the casing.
U.S. Pat. No. 5,875,847 discloses a multilateral sealing device comprising a casing tool having a lateral root premachined and plugged with cement. A profile receives a whipstock for the drilling of the lateral bore hole through the lateral root and cement plug. A lateral liner is then inserted and sealed within the lateral root.
TAML (Technology Advancement Multi-Lateral) defines six levels for a multi-lateral junction for a lateral borehole. For example, level three merely includes a junction with the main casing and a liner extending into the lateral borehole without cementing or sealing the junction. If the liner is merely cemented at the junction, it is a level four since cement is not acceptable as a seal. Level four simply includes cement around the junction. Level five requires pressure integrity at the junction.
Prior art multilateral wells are sealed with cement using a method well-known to those with skill in the art and described hereinafter.
Level five includes seals used to achieve pressure integrity around the junction. For example, in level five, separate tubulars extend through the main borehole and through the lateral borehole. A packer is placed around the upper ends of these tubulars to pack off with the casing of the cased main borehole. The lower end of the tubular extending through the main tubular includes a packer for sealing with the main tubular below the junction, and the lower end of the other tubular extending through the lateral borehole seals with an outer tubular in the lateral borehole below the junction. The lateral borehole preferably has been previously cased so that a seal can be set with that tubular extending into the lateral borehole. Since there are separate tubulars and both bores are now packed off, there can be independent production from each bore without commingling. The pair of tubulars above the junction may extend all the way to the surface, or one well may be produced through a production pipe extending to the surface and the other well may be produced through the annulus formed by the casing and the production pipe extending to the surface.
Where the formation pressure is substantially the same in the pay zones being produced by the main and lateral boreholes, the hydrocarbons from the main and lateral boreholes may be commingled. However, it is sometimes desirable to separate production so that each well can be independently controlled, such as where the pay zone pressures are different. In that case, separate tubulars are used to produce the individual wells, as previously described in a level five junction, or one well may be plugged off if necessary. Whether production is commingled or independent has no bearing on how a multilateral well is classified.
If the formation is a solid formation, the lateral borehole, for example, need not even include a casing or liner and may be produced open hole. If the lateral borehole is unconsolidated or unstable and would tend to cave in, the lateral borehole would be cased off or include a liner to contain the formation. For example, it is common in the prior art to run and set a liner in the lateral borehole with the liner extending from the flowbore of the casing and down into the lateral borehole. Cement is then pumped down through the cased main borehole, across the junction into the lateral borehole below the junction, and into the lateral borehole both inside and outside the liner. Then, the bore of the cased main borehole is cleaned out by drilling out the cement, including milling off that portion of the liner extending into the bore of the cased main borehole, leaving an exposed end of the liner at the junction which extends into the lateral borehole. The liner is then cleaned out giving access to both the main and lateral boreholes. This procedure is tedious and includes the problem of the drill tending to enter the liner as it removes the cement and liner end from the main borehole. This method is also problematic because the cement acts as both the junction and the seal. The cement is subject to failure due to limitations in the cement material itself or the ability to place the cement successfully at the junction. More particularly, under downhole conditions, cement can fail by deteriorating to such an extent that the seal begins to leak thus contaminating the production fluids.
An alternative to the above-described method is described in pending U.S. patent application Ser. No. 09/480,073, filed Jan. 10, 2000 and entitled xe2x80x9cLateral Well Tie-Back Methods and Apparatus.xe2x80x9d A lateral well tie-back apparatus and method is used to help ensure adequate flow and production from a lateral bore.
There are a variety of additional configurations that are possible when performing multilateral completions. For example, U.S. Pat. No. 4,807,704 discloses a system for completing multiple lateral wellbores using a dual packer and a deflective guide member. U.S. Pat. No. 2,797,893 discloses a method for completing lateral wells using a flexible liner and deflecting tool. U.S. Pat. No. 3,330,349 discloses a mandrel for guiding and completing multiple lateral wells. U.S. Pat. Nos. 4,396,075, 4,415,205, 4,444,276, and 4,573,541 all relate generally to methods and devices for multilateral completion using a template or tube guide head. For a more comprehensive list of patents, U.S. Pat. No. 6,012,526 details these configurations and presents a patent literature history of the well-recognized problem of multilateral wellbore completion.
Notwithstanding the above-described attempts at obtaining cost effective and workable lateral well completions, there continues to be a need for new and improved methods and devices for providing such completions, particularly sealing between the juncture of primary and lateral wells, the ability to re-enter lateral wells, particularly in multilateral systems, and achieving zone isolation between respective lateral wells in a multilateral well system. The present invention relates to a new and improved method and apparatus for the construction and completion of a multilateral well junctions, and overcomes the deficiencies of the prior art.
A junction for the intersection of a main borehole and a lateral borehole includes a main tubular having a main window with a ramp aligned with the main window, and a lateral tubular adapted to be telescopingly received within the main tubular and having a lateral window. The main tubular and lateral tubular each have an orientation surface. The lateral tubular has a first position with one end partially disposed within the main tubular. The lateral tubular is telescoped into the main tubular with the end of the lateral tubular engaging the ramp which guides the end of the lateral tubular through the main window and into the lateral bore. The orientation surfaces engage to orient the lateral window with the main window and form a common opening between the tubulars. The ramp is preferably an arcuate surface at an angle to the axis of the main tubular and extends along the edges of the main window between the inner and outer diameters of the main tubular. The orientation surfaces are preferably mule shoe surfaces which engage to rotate the tubulars into alignment.
The junction may also include a shear member to releasably connect the lateral tubular within the main tubular until the junction is to be deployed. Once the lateral tubular is released, preferably by shearing the shear member, it telescopes down into the main tubular until the lateral tubular reaches the ramp adjacent the main window. The ramp deflects the lateral tubular out through the main window by engaging the end of the lateral tubular. The lateral tubular has one end extending from the main tubular to form the junction between the lateral borehole and the primary borehole. The main tubular extends into the main borehole and the lateral tubular extends into the lateral borehole.
The present invention is also directed to a method of multilateral well completions. To create a lateral well bore, a milling assembly is run into the main well bore to a desired depth and orientation. An anchor and/or packer are set. If a well reference member is not previously set, a reference member may also be set on the same run. A window is milled in the cased borehole and a lateral rat hole is drilled. The milling assembly and whipstock are then removed. The junction with main tubular and lateral tubular is run into the main bore in substantial alignment. The lateral tubular is partially disposed within the main tubular and is releasably held by a shear member. The main window becomes aligned with the lateral rat hole when an orienting member at the bottom of the main tubular engages the downhole well reference member, thereby rotating and orienting the junction assembly.
A weight is applied to the lateral tubular causing the lateral tubular to disengage the main tubular allowing the lateral tubular to be received within the main tubular. Any misalignment that occurs while the lateral tubular is deflected out of the main window via the ramp is corrected when the lateral orientation member engages the orientation surface of the main tubular. When the lateral orientation member and the main orientation surface are fully engaged, the lateral and main windows are substantially aligned and facing each other to form the junction.
There are many benefits to using the present invention. Critical work is done prior to exposing the time dependent formations. A level four multilateral well can be achieved without milling excess liner. A minimal amount of cementing is required, although cementing is optional for the present invention. The access diameters for both the main and lateral tubulars are maximized. The present invention allows re-entry capabilities in both bores.
Other objects and advantages of the invention will appear from the following description.

Method and apparatus for multilateral junction


An air booster power nozzle for use in combination with a vacuum cleaner having a motor/fan unit for creating a vacuum, the power nozzle including an enclosed base having a suction inlet for air and an air outlet spaced from the suction inlet, a power source and a motor energized by the power source, a suction-creating fan rotatably supported by the motor and sited relative to the enclosed base adjacent the air outlet; the motor/fan units of the vacuum cleaner and of the power nozzle operating in tandem for creating an extremely high suction and vacuum at the power nozzle to forcefully remove debris from the surface being cleaned and to preclude plugging of the power nozzle or the vacuum cleaner.

1. Field of the Invention
The invention relates to and is limited to a power nozzle of a vacuum cleaner system, such as a canister type vacuum using a power nozzle or a central vacuum system using a power nozzle.
2. Description of Related Art
The nozzles produced in today's market reflect such things as straight suction tools, which clean a carpet by means of suction created at the canister or the central vacuum. There is also available an air-driven power nozzle type wherein the suction created at the canister or central vacuum turns a squirrel cage type fan, which sequentially turns a brush roller, without the use of electricity. This is one step above a straight suction tool in cleaning ability. The next step is an electric power nozzle which has a small electric motor which turns a brush roller, the suction created at the canister or the central vacuum being what actually picks the dirt up from the surface being cleaned.
In prior art devices, no means is provided for movement where the wand attaches to the nozzle. Therefore, the user cannot manipulate the nozzle in a back and forth motion, thus giving an awkward feel to any vacuuming procedure.


A method and apparatus for generating dual tone multiple frequency signals employing a low frequency quartz oscillator, wherein a phase accumulation dual tone multiple frequency generator is comprised of a low frequency quartz oscillator. Two phase selectors are connected to produce digital phase signals in response to a signal input. Two phase accumulators, each composed of an adder and a register, are connected to accumulate the phase signals. Two ROM based sine wave tables are addressed by the outputs of the accumulators. An adder adds the outputs of the ROMs, and a D/A converter produces an analog output from the output of the adder.

Conventional DTMF generators employ analog circuit techniques. For instance, known tone dialer CIC 9145 employs analog circuits. With this construction, low frequency quartz crystals cannot be employed to generate the system clock for accurate DTMF signals. Since the frequency that composes the DTMF signal must be divided into thirty-two parts every cycle, the lowest frequency of the system clock in the tone dialer must be higher than a few hundred kilohertz for an accurate DTMF signal. This results in an increase of the operating current, and also increases the cost of the device. In addition, analog integrated circuits are difficult to test, and the parameters of analog IC's are sensitive to the testing process.
FIG. 3 is a block diagram of a conventional tone dialer. The DTMF generator portion consists of three blocks: a data latch and encoder 100, a row and column programmable counter 200, and a D/A converter 300. With this architecture, it is impossible to use a low frequency quartz crystal (e.g. 32768 Hz) to generate a DTMF signal with high accuracy, and it is also difficult to change the output frequency. If it is necessary to change the output frequency of a conventional DTMF generator, it is necessary to employ different hardware.

Phase accumulation dual tone multiple frequency generator

Industrial Technology Research Institute


An analyzing method of a blood coagulation reaction by detecting an optical change of a blood sample with an elapse of time, the method includes: setting at least one checkpoint or check region between a starting point of the blood coagulation reaction and the endpoint thereof; and monitoring a reaction state of the blood coagulation reaction at the checkpoint or in the check region to detect an abnormality of the blood coagulation reaction.

1. Field of the Invention
The present invention relates to an analyzing method of a blood coagulation reaction. More particularly the invention relates to an analyzing method of a blood coagulation reaction for measuring a blood coagulation time, the method being capable of detecting abnormality in the blood coagulation reaction.
2. Description of Related Art
Blood coagulation detection methods include the method of detecting the increase in viscosity (viscosity detection method), the method of detecting turbidity (turbidity detection method), and their combined method.
In the viscosity detection method, a bar-shaped or spherical magnetic element is placed in the plasma specimen, and a coagulation reagent is added. The motion of the magnetic element becomes slower due to coagulation, and this slowing down is detected.
However, The viscosity detection method produces variable results depending on the shape of the fibrin clumps which are the final product of blood coagulation (that is, the quantity or viscosity of the fibrin). Furthermore, it is impossible to detect coagulation unless the viscosity increases to above a specific level. Besides, because the measurement principle is based on observing the motion of the magnetic element, it is dependent on the strength of the magnetic field of the element.
The turbidity detection method involves mixing the plasma specimen and coagulation reagent, and it does not require a magnetic element or the like. The method can be the transmitted light detection method or the scattered light detection method. With these methods of detection, if the fibrinogen quantity is small, the change in the quantity of transmitted or scattered light can be detected, and it is hence free from the shortcoming of the viscosity detection method.
Methods for analyzing a blood coagulation point include: (1) a percentage detection method; (2) a differential method; (3) a double differential method; (4) an inflection point method; (5) a fluctuation detection method and the like. Among them, in the percentage detection method, the blood coagulation point is detected as a point showing a 50% optical change amount relative to the optical change amount when the blood coagulation finishes, at which point an optical change rate per a unit time is the largest and the rate of polymerization reaction of fibrin monomers is high. Thereby more precise coagulation measurement can be performed for samples such as low fibrinogen samples, chyle samples and laked blood samples.
Normally, for analyzing a blood coagulation reaction, plasma is mixed with a blood coagulation reagent to start the blood coagulation reaction, and the degree of turbidity during the process of the plasma coagulating, that is, during the process of fibrin formation, is detected as a change of the intensity of a signal by an optical detector. If the optical detector is of a scattered light detection system, such a change is represented with time plotted in abscissa and the scattered light amount (intensity) plotted in ordinate, for example, as shown in FIG. 1.
Point A in FIG. 1 indicates a time when plasma is mixed with a coagulation reagent to start the blood coagulation reaction. Then, the blood coagulation reaction advances through a cascade reaction. As stable fobrous fibrin is formed by fibrinogen in the plasma, a change appears in the amount of scattered light (point B). As the formation of the stable fibrin advances, the amount of the scattered light increases. When most of fibrinogen is consumed, the amount of scattered light does not change any more and the blood coagulation reaction terminates (point C). Supposing that the amount of the scattered light at point B is taken as 0% (non-coagulation level) and the amount of scattered light at point C is taken as 100%, a blood coagulation time may be defined as a point where the amount of the scattered light reaches 50% (point T). ΔH is indicative of a change of the amount of scattered light from the start of the blood coagulation reaction to the termination thereof.
Typically, the following complicated process leads to the formation of fibrin. The blood coagulation progresses by two pathways in general: One pathway is called as an extrinsic pathway, through which, starting with tissue thromboplastine discharged from epidermic cells and the like, the coagulation factor VII is activated, which in turn activates the coagulation factor X, then, the activation of the coagulation factor V and the factor II occurs, and finally, fibrinogen is transformed into fibrin. In general, the strength or weakness, that is, the normality or abnormality, of the blood coagulation reaction through this pathway is judged by measuring a "prothrombin time (PT)."
The other pathway is referred to as an intrinsic coagulation, through which the coagulation factor XII is activated by contacting the surface of a solid phase having a negative charge and then activates the factor XI, the activated factor XI in turn activates the factor IX, and further, the activated factor IX activates the factor X with collaborative action of calcium ions and the factor VIII, then, the activation of the factor V and the factor II occurs, and finally, fibrinogen is transformed into fibrin. In general, the strength or weakness, that is, the normality or abnormality, of the blood coagulation reaction through this pathway is judged by measuring an "activated partial thromboplastine time (APTT)," a "partial thromboplastine time (PTT)."
In addition, at the final stage of the coagulation reaction, fibrinogen is required to be transformed into fibrin, whereby the coagulation completes.
As described above, the blood coagulation is a multiple-stage reaction, and thus, when abnormality occurs with the reaction pathways, unstable behavior may be expressed. For example, the reaction falls in such a state as if the reaction apparently stops temporarily in the middle of the reaction (an optical change is not observed), or alternatively, a gradual optical change is observed immediately after the blood coagulation reagent is introduced into plasma. Thus there are cases in which the reaction curve as shown in FIG. 1 is not always produced.
As an example, in the case where the coagulation time is measured based on an optical change amount with respect to high fibrinogen samples collected from heparin-administered patients, APTT sometimes tends to be extremely short. It is considered that such samples exhibit a two-bump reaction (the blood coagulation curve has two increase phases) due to a coagulation reaction caused by an extrinsic sthenia state as shown in FIG. 2: The optical change amount of the samples gradually increases with an elapse of time from the initial stage of the reaction, and then the optical change amount is larger than that of a normal coagulation reaction (second stage). As a result of such behavior different from usual, an incorrect coagulation time is considered to be computed.

Analyzing method of a blood coagulation reaction


A key telephone set comprises a telephone main body, an interchangeable dial button unit, an interchangeable line button unit, and an interchangeable display unit. The interchangeable dial button unit, the interchangeable line button unit and the interchangeable display unit are attached to the telephone main body while they can be detached from the telephone body from a top surface side of the key telephone set without disassembly of the telephone main body.

This invention relates to a key telephone set and a key telephone system including the key telephone set, in particular, to a key telephone set having interchangeable function units which can be attached/detached to/from a telephone main body without disassembly of the telephone main body.
The key telephone system generally comprises a main device (or a key service unit) and a plurality of key telephone sets connected to the main device.
To meet various demands from users, it is necessary to provide some or many types of telephone sets. For instance, a user needs a display portion while another user needs no display portion. Furthermore, a user needs a small number of line selection buttons for extensions and outside lines while another user needs a large number of the line selection buttons.
An existing key telephone set comprises a telephone main body, a display assembly and a selection button assembly. The display assembly and the selection button assembly are attached to the telephone main body. The display assembly and the selection button assembly can be detached from the telephone main body when the telephone main body is disassembled. Providing interchangeable display assemblies and interchangeable selection button assemblies correspond to providing various types of telephone sets. That is, functions of the key telephone set can be easily changed by the use of different display and different selection button assemblies together with the telephone main body. Such a key telephone set is disclosed in Japanese Unexamined Utility Model Publication No. 5-6961.
Another existing key telephone set comprises a telephone main body, dial and function button units and a decorative panel for positioning the button units on the telephone body. The decorative panel can be detached from the telephone main body from the top surface side of the telephone main body. The dial and function button units can be freely separated from the telephone main body when the decorative panel is detached from the telephone main body. This is because the dial and function button units are merely placed on a predetermined position of the telephone main body. Accordingly, specification of the key telephone set is easily changed by changing the button units for different button units. Such a key telephone set is disclosed in Japanese Unexamined Patent Publication No. 2002-75114.
As a related technique, there is a radio communication apparatus, which is not a key telephone set. The radio communication apparatus comprises a main body and a detachable operation button block which is attached to the main body and which can be detached from the main body. Functions of the radio communication apparatus are changed by the changing the operation button block for a different operation button block Such a radio communication apparatus is disclosed in Japanese Registered Utility Model Publication No. 3004142.
However, the existing key telephone set using the display and the selection button assemblies has a fault that the telephone main body must be disassembled to detach the display and the selection button assemblies from the telephone main body. This is because each assembly has hooks and claws for engaging with the telephone main body while the hooks and the claws can not be disengaged from one another from the outside of the telephone main body.
Furthermore, the other existing key telephone set using the button units and the decorative panel has a fault that it is impossible to meet the user's demands about the number of the line selection buttons and/or about having a display unit or not. The related radio communication apparatus has as similar fault because the operation button block is collectively attached/detached to/from the main body.

Key telephone set having interchangeable units


This disclosure describes a transportation matching system that manages the allocation of transportation providers by training and utilizing multiple machine-learning models to identify, allocate, and serve specific transportation providers with customized opportunities to relocate the transportation providers between geocoded areas in a geocoded region. For instance, the transportation matching system trains and utilizes an incremental provider model, a provider allocation model, and personalized provider behavioral models as well as a customized provider interface generator to satisfy anticipated transportation requests and improve transportation matching within a geocoded region.

In recent years, popularity and usage of on-demand transportation matching systems have significantly grown. Indeed, the proliferation of web and mobile applications easily enable requesting individuals to request transportation from one geographic area to another geographic area. For instance, an on-demand transportation matching system receives transportation requests and pairs the requests with providers that can transport requesting individuals to the destination locations. In addition, the on-demand transportation matching system provides tools to providers to pick up requesting individuals as well as transport them to the destination locations.
Some existing on-demand transportation matching systems manage networks of hundreds of thousands of providers as well as millions of requesting individuals. Furthermore, within a short time period, these on-demand transportation matching systems are often required to process thousands of transportation requests for a geographic area, where each request involves matching a requesting individual to a provider. Because of the significant technical complexity required to process such large volumes of transportation requests—often occurring at unexpected times—on-demand transportation matching systems often suffer from computational problems and inefficiencies.
As an initial problem, when a large number of transportation requests are received in a short timeframe within a region, these on-demand transportation matching systems commonly struggle to appropriately match the transportation requests because there are not enough providers within a satisfactory distance of the requesting individuals. Indeed, it is typical for the number of received transportation requests for one area to exceed the number of available providers, while at the same time, another area may have a surplus of available providers to the number of transportation requests. This results in delays in processing and matching each transportation request, which thereby increases the number of transportation requests that a transportation matching system handles at any particular time, thereby increasing the computational strain on the transportation matching system.
Some on-demand transportation matching systems have attempted to better allocate available providers across multiple areas to better match the demand of each area. However, these on-demand transportation matching systems have failed to identify an efficient approach that accurately redirects available providers to areas where transportation requests are anticipated. Indeed, these on-demand transportation matching systems employ approaches that are rigid, overly complicated, and computationally inefficient, which prohibits operation in near-real-time. Thus, because these on-demand transportation matching systems rely on outdated information, too often, these systems send providers to areas where they are not needed, wasting the computational resources of the system as well as the time of the providers.
These along with additional problems and issues exist with conventional transportation matching systems.

Efficiency of a transportation matching system using geocoded provider models


The present invention provides a filter for drinking water, including six filtering bottles. The fifth filtering bottle is formed with ion exchange resins, and the sixth filtering bottle is formed with a ceramic filtering core. The arrangement of the original third and fourth filtering bottles of the prior art is transposed, and a device for preventing a magnet of the filter from rusting is provided. The filtering bottles are orderly in turns and connected by tubes, and the fourth filtering bottle is connected with the fifth and sixth filtering bottles by a three-way pipe. Water is poured into a first filtering bottle and discharged from the fifth or sixth filtering bottle.

FIG. 1 is an illustrative view of a conventional filter for drinking water; water is poured into a left inlet tube 11 through a first filtering bottle 1, a second filtering bottle 2, an original third filtering bottle 3′ and an original fourth filtering bottle 4′, and discharged from a right outlet tube 41′ for drinking.
The filtering core of the first filtering bottle 1 is nonwoven in order to filter silt, rust, plankton and the like.
The second filtering bottle 2 is formed with a ceramic filtering core, which can filter the bacteria in the water such as colon bacillus.
The original third filtering bottle 3′ includes a compressed active carbon filtering core and a special alloy of copper and zinc (sold under the trademark KDF 55) for filtering chlorine, chemical poisons, pesticides, heavy metal and the like.
The original fourth filtering bottle 4′ is formed with an activated energy transformer, which is filled with different kinds of minerals that can radiate far infrared in order to activate the water with energy of far infrared. A magnet can be added to the original fourth filtering bottle 4′ for magnetizing the water.
However, the conventional filter for drinking water still has some disadvantages as follows:
Firstly, the magnet that is added to the original fourth filtering bottle 4′ will be rusted because it is dipped in the water, thereby the magnetism of the magnet will be reduced and the water will not be magnetized efficiently.
Secondly, the different kinds of minerals that are added to the original fourth filtering bottle 4′ will breed bacteria easily. The water therefore becomes contaminated without a subsequent filter to filter the bacteria.
Thirdly, the different kinds of minerals that are added to the original fourth filtering bottle 4′ will produce many mineral substances when dissolved in the water, and beverages made with this water will be contaminated with these mineral substances (e.g., calcium and magnesium). For instance, tea made with this water will be contaminated with calcium carbonate and magnesium carbonate.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.


A loop manufacturing process which utilizes a gang of needles, each including a closing string and a hook, and at least one transverse gang of small strainers located on either side of a sheet in conventional fashion, together with a transverse gang of longitudinal lancets. The sheet is continually fed from the top to the bottom of a knitting machine to obtain a loop material forming one of two cooperating parts of an self-gripping strap. After the formation of at least a first loop on a lancet and before the formation of a second loop on the lancet, the lancet holding the first loop moves transversely in one direction and by a predetermined distance. After the formation of the second loop on this lancet, the lancet holding the first and second loop moves transversely by the same distance but in the opposite direction, before and for the formation of a third loop on this lancet. The cycle of transverse movement of the lancet in one direction and then the other is repeated every two loops.

Auto-gripping straps are an extremely widespread application in the manufacturing of clothing, or generally, in domestic applications.
Said straps consist of two parts. A first part comprising of the loops which are destined to cooperate, through a redundant hooking link, with a second part, for instance hooks, string-like elements with an over-sized head, analogue elements, etc.
For evident, cost-based reasons, particularly important when single-use articles are to be mass-produced, notably diapers, one has to research economical manufacturing processes.
An economical process known for garments, for instance in the form of bands, of the part comprising the loops of this type of strap, is the manufacturing of a laminate consisting of a chained or weft material with loops counter-glued on a support.
However, this process is relatively complex, in so far as it necessitates a separate preparation for each of the two external layers of the laminate, then a technically complex gluing operation.
The present invention therefore relates to the manufacturing process of a loop cloth, the steps of which are fewer and therefore simpler than those intervening in the manufacturing of a laminate.
A process of this type is put to use on a knitting machine, modified to produce a loop cloth, described in the American U.S. Pat. No. 4,003,222, published on Jan. 18, 1977.
The modification consists of the transformation of the fixed lancets system in a mobile system. The lateral movement of the lancets allows for high-speed hook manufacturing, with a very high degree of dimensional stability, over a knit framework.
The manufacturer of this machine, the German company LIBA MASCHINENFABRIK, had solved the problem of optimal control of the string in an original and efficient fashion.
It is also with a view to increase the speed and quality of production guides can be used on this machine type, as for instance on the knitting machine of the aforementioned company, described in the European patent application EP 511580, published on Nov. 4, 1992.
However, regardless of the quality of the product manufactured, the problems that arise from the mechanically fragile and dimensionally unstable structure of a knitted material remain.
Another known process consists of inserting loops in a sheet. The material this sheet is made of could feature all required characteristics, both in terms of resistance and flexibility.
Textile machinery that can operate this process is available on the market in different forms.
The main machine is manufactured by the company MALIMO. It produces stitched loops from a simple or double knit armor. The machine includes a gang of fixed lancets.
There also exist a few machines using hooks, which produce loops either as frames or stitched, by insertion on a sheet. In this case, the lancets are still fixed.
The fact that loops manufactured through these processes are flat on the surface of their support is a negative consequence of the fixedness of lancets. The ease of strapping complementary elements of the strap is therefore naturally decreased compared to the expected result of using perfectly straight loops.
The conclusion derived from the above review of the existing state of the process is that manufacturing processes that knit loops on a sheet are known, but there exist no simple and economical process that provides full satisfaction today. Particularly, loop cloth manufactured by those processes features neither the dimensional stability nor the structural characteristics required for heavy-duty applications, notably diapers.

Manufacturing process of loops on a sheet through knitting, loop material manufactured by this process and its use


A method of cleaning the bottom of a feeding channel supplied fresh water to be fed to fish such as fry of salmon and trout is disclosed in which a baffle means for preventing the flow of water in the feeding channel is maintained to the orientation such as to extend upwardly from the height position spaced apart upwardly from the bottom to block the flow of water in the channel while the baffle means is moved in the channel from the upstream side to the downstream side, thereby collecting the deposit in the channel toward the downstream side of the channel due to the flow of water passing through the gap between the bottom and a lower edge of the baffle means. An apparatus for cleaning the bottom of a feeding channel comprises a baffle means disposed in the feeding channel and movable from the upstream side to the downstream side so as to block the flow of water in the channel which is supplied with fresh water thereto and a means for maintaining the baffle means to the orientation such as to extend upwardly from the height position spaced apart upwardly from the bottom to block the water flow in the channel while the baffle means is moved in the channel.

1. Field of the Invention:
This invention relates to a method of cleaning the bottom of a channel for feeding fish and an apparatus thereof and, more particularly to a method and an apparatus suitable for cleaning the bottom of a feeding channel for fry of salmon, trout or the like.
2. Description of the Background Art:
The incubation of salmon and trout such as pink salmon, masou salmon, trout, char and like fish usually comprises a breeding step, in which fertilized eggs are bred, a repose period control step for controlling a repose period of yoke sac fry in an incubation channel where fresh water flows at all time, and a feed step, in which free swimming fry in a free swimming period after the repose period is fed in a feeding channel where fresh water flows at all time.
A feeding channel having substantially the flat bottom free from the inclination is used for feeding of free swimming fry. The feeding channel is supplied fresh water at all time such as to maintain the flow of water in said channel to a predetermined velocity. The grown free swimming fry is transferred from the incubation channel to said feeding channel and further the bait for the free swimming fry is sprayed over said channel.
The feeding channel may be used as the incubation channel. In this case, a member, i.e., gravels disposed in the incubation channel in order to provide a repose place for the yolk sac fry is removed from the incubation channel.
A deposit forms on the bottom of the feeding channel which is precipitated by the resisual of the bait sprayed therein, excrements of fish and mud or the like. The deposit noted above is widely distributed over the entire surface of the bottom and flows up through the water to disperse therethrough. In this case, the water is liable to contaminate. When the deposit is left on the bottom as it is, corrosion of said deposit produces the pathogenic bacteria of fish and fur or the like, thereby rapidly contaminating the inside of the feeding channel and is liably to produce fish deseases and oxegen starvation or the like. As a result, it has been desired that the feeding channel should be cleaned by entirely removing the deposit produced over the entire surface of the bottom of channel as frequently as possible, i.e., every day or every few days.
One of an apparatus for cleaning the bottom of the feeding channel has been disclosed in which a cleaner enters the channel to withdraw the deposit by using an elongate pipe and a suction pump. However, the apparatus noted above is liable to suck up fry on the bottom even when the suction force of the suction pump is reduced. Further, according to the apparatus, an end of said pipe should be moved by hand slowly along the bottom of the channel while paying attention so as not to disturb the deposit through the water. Therefore, it takes much time for cleaning and is substantially impossible to clean each bottom of a plurality of feeding channels every day or every one or other day. As a result, from the practical point of view, the apparatus noted above is merely used for occasionally removing the deposit which is locally collected on the bottom of the feeding channel and is clearly visible to the eye.
Thus, there has been developed up to now an apparatus for removing efficiently and economically the deposit which is liable to disturbed through water from the bottom and widely distributed over the entire surface of the bottom without contaminating the channel even when the deposit is dispersed through the water and damaging the fry. Therefore, only the occasional removal of the deposit which particularly leaps to the eye has been conventionally performed. The entire surface of the bottom of the feeding channel has not been cleaned during the feeding period of fry but cleaned after said period.

Method of cleaning bottom of feeding channel for fish and apparatus thereof