The impeller for a centrifugal pump includes a carrier disk and possibly a shroud. The blades of the impeller are identical, but are arranged in pairs such that impellers of different hydraulic characteristics are formed with blades of the same shape.

The present invention relates to an impeller for a centrifugal pump.
Impellers for a centrifugal pump typically include at least a carrier body, typically of a carrier disk, and blades arranged thereon. The carrier disk is thereby regularly designed for the rotationally fixed arrangement on a shaft. The impeller blades, depending on the construction type, lie exposed (open impeller) or covered by a shroud, which lies opposite the carrier disk and is connected to the blades. The impellers are known in different construction forms and are applied in single-stage or multistage centrifugal pumps. The impellers typically comprise two or more impeller blades, which may be designed and/or arranged in an equal manner or also in a differing manner.
For example, the impeller represented in FIG. 1 comprises a circular carrier disk 1, which comprises a central recess 2, which is profiled and is envisaged for the rotationally fixed connection to a drive shaft (not shown), as is counted as belonging to the state of the art with centrifugal pumps. A multitude of impeller blades 3 is arranged on the carrier disk 1, which extend at a distance to the recess 2, up to the outer periphery of the carrier disk 1. The blades 3 on the side lying opposite the carrier disk 1 are covered by a shroud 4, which in the embodiment according to FIG. 1 runs out on the inner side into an annular section 5 which forms the run-in of the impeller, as is known per se and is therefore not described in detail.
The shape and the arrangement of the blades 3 may be recognized with a removed shroud 4, as is shown by way of example in FIG. 2. The impeller according to FIG. 2 as a whole comprises six blades 3, which have the same shape and size, and are arranged at the same angular distance on the carrier disk 1.
With impellers formed of plastic, which are manufactured with the injection molding method, as a rule a separate tool is required for each change on the impeller. However, blades of a different arrangement and size may be provided on an impeller, without increasing the manufacturing costs. If, however, the impeller, as is the case with a multitude of centrifugal pumps, is formed of sheet metal, typically of stainless steel sheet metal, then different tools are required for different blade shapes, which increases the manufacturing costs. The manufacture itself is effected by way of aligning the individual blades on the carrier disk and these being welding to this, whereupon, as the case may be, the shroud is applied and likewise welded to the blades.
In order to be able to cover a multitude of application cases, centrifugal pumps are offered in different constructional sizes. The size variation is, however, not only varied by way of changing the geometric dimensions and the drive power, but also by way of variation of the blades. If an impeller, for example, which delivers a certain delivery rate at a given pressure, is to be designed with regard to a reduced delivery rate, then for example the blade height may be reduced accordingly. However, natural limits are placed on this, since a minimum passage height must be retained within the impeller in order to ensure fault-free operation. With cast impellers, it is counted as belonging to the state of the art to fill out intermediate spaces between blade pairs in order to reduce the delivery rate. With impellers manufactured of sheet metal, this is not possible, or only with an increased expense by way of arranging two blades for forming a dead space. However a separate punching tool is necessary for each of these impellers.


A method of determining the average current drawn by an electric motor, the motor comprising a plurality of phases, the method comprising: driving each phase of the motor with cyclic pulse width modulated drive signals having a first state and a second state, and a duty ratio indicative of the ratio of time spent in the first to second states within a cycle, determining the current flowing through each phase at an instant in the cycle; and determining the average current drawn by the motor over at least one cycle by combining the currents flowing through each phase with the duty ratios for each phase. The method may be embodied in a combination of a motor and a drive circuit for the motor, such as can be used in an Electric Power Assisted Steering system.

This invention relates to a method of determining the average current drawn by an electric motor, and to related apparatus.
In many automotive applications, it is useful to be able to provide a measure of the battery current draw whilst a system is in operation. For large electrical components such as an electric power assisted steering (EPAS) system, it is common to transmit the battery current information to other components on the vehicle to enable load-levelling to be carried out to improve battery/alternator performance.
For cost-sensitive automotive applications, this ideally needs to be done without adding any cost to the system. However, for systems such as permanent magnet AC motor drives which use a single current sense series with the motor phases to measure the three phase currents, (for example, the circuit shown in EP 1 083 650 A2) it is not easy to directly measure the battery current, due to large fluctuations in drive current. An average current measurement is desirable.

Determining average current drawn by a motor


The present invention relates to a neutral grey glass composition which has a basic composition containing the following main coloring agents: 0.40 to 0.80% of Fe2O3; 0.05 to 2.0% of TiO2; 0.2 to 2.5% of Er2O3; 20 to 200 ppm of CuO; 0.08% to 0 0.1% charcoal; and 15% to 50% of ferrous (redox), in which the glass has light transmission “A” greater than 65%, solar transmission (TS) <55%, and ultraviolet transmission <40%, having color values a*=−4 to 3 and b*=4 to −2.

A. Field of the Invention
The present invention relates to a neutral grey glass composition, which has a basic silicon-sodium-calcium composition containing the following main coloring elements: 0.40% to 0.80% Fe2O3; 0.05% to 2.0% TiO2; 0.2% to 2.5% Er2O3; 20 to 200 ppm of CuO; 0.08% to 0.1% charcoal; and 15% to 50% ferrous (redox), in which the glass has light transmission under illuminant "A" greater than 65%, solar transmission (TS)<55%, and ultraviolet transmission <40%, having color values a*=−4 to 3 and b*=4 o−2.
B. Description of the Related Art
Colored glass is glass to which, during the manufacturing process, metallic oxides and some colorants such as selenium metal are added. As a result of previous research, it is known that the incorporation of selenium results in a salmon pink coloring, the combination of iron oxide and selenium Fe2O3—Se gives glass a brownish-reddish coloring; in addition, ultraviolet, visible and solar radiation transmissions are reduced. Furthermore, the incorporation of cobalt oxide (Co3O4) results in a blue coloring, the combination of iron-cobalt oxides confers tones which vary from violet blue (low iron) to dark blue with a greater concentration of iron oxide. Modifying the quantity and ratio of the three colorants "selenium-iron and cobalt oxide", when added to oxide-reduction conditions in the glass blending/mixing atmosphere, one obtains glass with high transmission of light, good blockage of solar heat and also colors, including grey.
Grey glass is traditionally obtained from the combination of various colorants: green is generated by iron oxide (Fe2O3), pink by Selenium (Se) and blue via cobalt oxide (Co3O4); some patents replace (CO3O4) with nickel oxide (NiO) and manganese oxide (MnO).
Neutral colored glass with low light transmission can be processed by the combination of colorants Fe2O3—Se—, Co3O4 modifying the concentrations and ratios.
Various patents have been developed for obtaining grey glass, for "automotive" purposes, which have a light transmission of greater than 70, which complies with the U.S. Federal Motor Vehicle Safety Standards. In the case of the construction industry, there is no restriction, and smaller values can be used, as well as thicknesses of between 1.6 and 12 mm.
The glasses described in almost all prior art patents refer to a type of grey glass for automotive purposes, which are based on three basic components: iron oxide, cobalt oxide, and selenium. These components are also combined with nickel oxide or manganese oxide, commonly called manganese dioxide, using different proportions, and together with the typical glass formulation of silicate-sodium-calcium, constitute the basic composition of the glass.
The Effect of Iron Oxide (Fe2O3) on Silicate-Sodium-Calcium Glass
Iron is present in (silicate-sodium-calcium) glass in two states of oxidation: as ferrous oxide (FeO) and ferric oxide (Fe2O3). Each state of oxide reduction confers different properties; the ferrous ion has a wide and strong absorption spectrum centered at 1050 nm, which translates into a reduction in infrared radiation. In addition, this spectrum extends to the realm of the visible, reducing the transmission of light and providing a bluish coloring to the glass; on the other hand, the ferric ion has a strong absorption spectrum centered in the ultraviolet region, which impedes the transmission of ultraviolet radiation through the glass, and two other weaker spectra in the visible region, located between 420 nm and 440 nm, which causes a slight reduction in light transmission and a yellowish coloring in the glass [1,2].
The balance between ferrous and ferric oxide has a direct effect on the color and transmission effects of the glass.
            %                                                        Fe                      +            2                                            (          Ferrous          )                      =                  FeO        ×        100                    Total                                                            Fe          2                                  O          3                                %                                                        Fe                      +            3                                            (          Ferric          )                      =                                        Fe                                                                      2                                  O          3                ×        100                    Total                                                            Fe          2                                  O          3
The above means that the greater the quantity of ferric iron (Fe+3) present in the glass, the greater the absorption of ultraviolet radiation and the transmission of light will increase; as well as the yellowish tone; but if the content of ferrous iron (Fe+2) increases as the result of the chemical reaction of Fe2O3, the absorption of infrared radiation will increase, but the absorption of ultraviolet radiation decreases, along with the transmission of light (which is undesirable).
                    Fe                  3          +                                  (        Yellow        )              ↔                            Fe                      2            +                                            (          Blue          )                                  [                              Yellow            +            Blue                    =          Green                ]                        2                    Fe        2                          O        3              ↔                  4                FeO            +              O        2
The variation in the concentration of FeO in relation to Fe2O3 gives rise to a change in the color of the glass. The displacements in the tones can be modified from yellow (lower Tuv, greater TL and Ts), through green, blue until reaching amber. From prior experimental results, it has been found that the color changes in the following way.
Yellow—Low ferrous (12%)-High light transmission (High ferric ion)
Greenish-yellow (16%)
Yellowish-green (20%)
Green (25% typical value for green glass)
Bluish-green (29%)
Greenish-blue (35%)
Blue (50%)
Olive green (60%)
Champagne (65%)
Amber—High ferrous (75%)-Low light transmission (low ferric ion)
In order to control the balance between the ferrous and ferric oxide and to achieve solar control glass, it is necessary to establish various conditions, in the mix and in the melting atmosphere. In the former case, the concentration of reduction agents like carbon and oxidants, like sodium sulfate and sodium nitrate. In terms of the melting conditions, the atmosphere has to be adjusted with a greater or lesser oxygen content depending on the desired thermal performance and shading of the glass.
The Effect of Titanium Oxide (TiO2) on Silicate-sodium-calcium Glass
The most stable form of titanium in glass is tetravalent (Ti4+), which is explained by its 3d0 electronic configuration [Fernandez Navarro J. M. "El vidrio"; Superior Council of Scientific Research, Madrid, 1991]. The trivalent form could confer coloring, however this effect is no found in sodium-calcium-silicate glass [Weyl A. Woldemar "Colored Glasses", Society of Glass Technology, Scheffiel, 1976]. The document "Effects of titanium dioxide in glass" by M. D. Beals, The Glass Industry, September 1963, pp. 495 to 531, describes the interest that has been shown in titanium dioxide as a constituent of glass. The effects produced by the use of titanium dioxide, including the comments that TiO2 increases the refraction index to a great extent, increases light absorption in the ultraviolet region, and results in lower viscosity and surface tension. The data on the use of titanium dioxide in enamels indicates that TiO2 increases chemical durability and acts as a dissolvent. In general, clear glass that contains titanium dioxide can be found in all common glass formation systems (borates, silicates and phosphates). The different glass formation regions for systems which contain titanium dioxide are not grouped together in the same place, since the organization of the discussion is based more on the properties and uses of glasses that contain titanium dioxide, rather than simply their makeup.
The Effect of Copper Oxide (CuO) on Silicate-sodium-calcium Glass
Copper oxide normally gives silicate-sodium-calcium glass a blue-turquoise coloring, and a reduced light transmission, due to a wide spectrum of absorption located in the visible region, centered at approximately 780 nm. Nonetheless, this spectrum extends to the nearby infrared and ultraviolet spectrums, causing a slight reduction in these types of radiations in the glass. The bluish coloring is associated with the presence of the divalent copper ion, but copper can be present in its monovalent state and not give off color.
Therefore, the coloring and the properties that are conferred by this compound depend not only on the quantity of copper present in the glass, but also on the balance between the two states of oxidation [Bamford C. R., "Color Generation and Control in Glass," Elsevier, 1977].
Copper oxide is incorporated as a key element for developing the bluish coloring necessary to adjust the neutral grey tone [U.S. Pat. No. 7,902,097].
The Effect of Selenium in Silicate-sodium-calcium Glass
The addition of selenium to silicate-sodium-calcium glass can produce a pinkish coloring due to the presence of atomic selenium. Selenium is one of the most widely used physical decolorants for glass with traces of iron resulting from an undesirable impurity in the raw materials, due to the fact that its coloring neutralizes the ferrous and ferric ions present in the glass[Bamford C. R., "Color Generation and Control in Glass," Elsevier, 1977; Fernandez Navarro J. M. "El vidrio"; Superior Council of Scientific Research, Madrid, 1991].
The combination of iron and selenium in silicate-sodium-calcium glass confers a reddish-brown coloring and a decrease in light transmission, due to an absorption spectrum located in the visible region between 490 and 500 nm (a spectrum similar to that of atomic selenium). This spectrum extends to the ultraviolet region, also causing a decrease in this type of transmission in the glass.
The intensity of the coloring and the final properties of the glass are a function of the concentration of iron oxide and selenium in the glass.
For concentrations above 0.1% Fe2O3, selenium must be used together with small quantities of cobalt oxide <0.0001%, to better compensate the tonality of the iron; these mixtures achieve a neutral tone, however there is some impact on the visible transmission [Fernandez Navarro J. M. "El vidrio"; Superior Council of Scientific Research, Madrid, 1991].
The Effect of Erbium Oxide (Er2O3) on Silicate-sodium-calcium Glass
In recent years, the use of rare earth oxides, in the forms either of pure oxides or concentrates from various rare earth elements, have been gaining importance in the areas of both research and practical applications. Some studies treat the decolorizing effect of erbium oxide as a physical decolorant, which is explained by the characteristic pink color that it is capable of transmitting to the glass.
Research allows us to reach the conclusion that erbium oxide is an excellent physical decolorant for silicate-sodium-calcium glass. In the base glass studied (0.033% Fe2O3, Fe2+/Fe3+=0.26), we would require approximately 0.040% Er2O3 in order to achieve a satisfactory effect. The amounts of erbium oxide will naturally vary as a function of the iron content of the glass and the chemical decolorizing system used. For other types of glass, the use of the proposed calculation system would make it possible to deduce the most appropriate quantities of erbium for decolorization [Reference Gago Garcia R. E., Tamargo Joglar A., Estudio teórico práctico del empleo del óxido de erbio como decolorante del vidrio silico-sodico-calcico, Scientific Conference on Ceramics and Glass, University de Oviedo and the Spanish Ceramics and Glass Society, 1981].
Erbium oxide has some advantages compared to selenium, because of its chemical stability and the ease in managing dosages and control, since it is not volatile. In addition, the specific direction in which it acts on color is also clearly preferable.
We currently have knowledge of some developments that use basic components to produce colored glass, for example U.S. Pat. No. 7,071,133, by Arbab, et al, granted on Jul. 4, 2006, has a glass redox value of between 0.2 and 0.675; U.S. Pat. No. 6,821,918 by Boulos, et al, granted on Nov. 23, 2004, in which iron oxide, cobalt oxide, selenium and manganese are used as the principal components. The manganese compound is present in a quantity of from 0.1 to 0.5% by weight, but based on the MnO2 in the composition of the glass. The presence of manganese substantially prevents the formation of the color amber. This manganese compound can be added to the glass load components in a variety of ways, for example (but not limited to) MnO2, Mn3O4, MnO, MnCO3, MnSO4, MnF2, MnCl2, etc.
Some other glasses described in other patents, like those mentioned in the paragraphs below, in addition to the three compounds mentioned, have different metallic elements that confer the characteristics to the final product, which allow them a TLA >70%, so that they can be used in construction and in the automotive industry.
For example, U.S. Pat. No. 6,114,264, of Krumwiede, et al, granted on Sep. 5, 2000, in which the color of the glass is characterized by dominant wavelengths in the range of 480 to 555 nanometers, an excitation purity of no more than 8 percent, and a luminous transmission factor of 70 percent or more in a thickness of 3.9 millimeters. U.S. Pat. No. 6,998,362 of Higby, et al, granted on Feb. 14, 2006, in which the color of the glass is characterized by a dominant wavelength of less than 560 nanometers, with a color purity of no more than 6 percent and a visible light transmission of 70 percent or greater at a thickness of 4 millimeters, and in which the total percentage reduction of iron is between 21% and 34%. U.S. Pat. No. 7,179,763, of Teyssedre, et al, granted on Feb. 20, 2007, in which the glass has an overall light transmission under illuminant A of greater than 67% for a glass thickness of 3.85 mm; and U.S. Pat. No. 5,958,811 of Sakaguchi, et al, granted on Sep. 28, 1999, in which an infrared and ultraviolet radiation absorbing glass composition has a visible light transmission of 70% of more, measured with the standard CIE illuminator, when said glass has a thickness of between 3.25 and 6.25 mm. The composition of the glass includes CoO, Se and Fe2O3, as principal components, as well as rare earth elements CeO2 and La2O3.
U.S. Pat. No. 6,235,666 (Cochran, et al), U.S. Pat. No. 6,403,509 (Cochran, et al) and U.S. Pat. No. 6,498,118 (Landa, et al), U.S. Pat. No. 6,573,207 (Landa, et al), U.S. Pat. No. 6,521,558 (Landa, et al), U.S. Pat. No. 6,716,780 (Landa, et al), U.S. Pat. No. 7,135,425 (Thomsen, et al) and U.S. Pat. No. 7,151,065 (Thomsen, et al) are related to glasses with a luminous transmission of over 70 percent. Their main colorants are CoO, Se, and Fe2O3. Se and CoO can be totally or partially replaced by a combination of rare earth elements, such as Er2O3, Y2O3, Ho2O3, CeO2. Glass compositions related to the use of rare earths are included in U.S. Pat. No. 6,521,558 (Ksenia A., Landa, et al) and U.S. Pat. No. 6,573,207 (Ksenia A., Landa, et al), which are related to a grey glass composition which employ as a colorant at least ferric/ferrous oxide and erbium (Er2O3), and also preferably selenium and cobalt. U.S. Pat. No. 6,498,118 (Ksenia A., Landa, et al) refers to a glass composition that employs a colorant portion of at least one iron (total iron expressed as Fe2O3), erbium (e.g., Er2O3) and holmium (e.g., Ho2O3).
Furthermore, U.S. Pat. No. 5,308,805, of Baker et al, granted on May 4, 1994, describes a neutral grey glass with a low transmission, in which one of the elements claimed is nickel oxide in proportions of from 100 to 500 ppm.
In the past, the absorption of heat absorbing grey glasses which contained nickel in their structure frequently formed, during the melting of the glass, nickel inclusions in the form of sulfide, which appeared as small invisible particles that were impossible to see once the glass was formed. These nickel sulfide inclusions, due to their high thermal expansion coefficient, can cause thermal tensions sufficient to fracture a plate of glass. This is especially a problem when the glass pieces are subjected to thermal treatment, such as tempering, in which the presence of nickel sulfide causes an excessively high incidence of breakage as a result of the tempering process.
An additional disadvantage of glass which contains nickel is the change in color which they are subject to after the thermal process, for instance after tempering.
Furthermore, U.S. Pat. No. 5,308,805, of Baker et al, issued on May 4, 1994, describes a low transmission neutral grey glass, in which one of the components claimed is nickel oxide in proportions of between 100 to 500 ppm.
In the past, heat absorbing grey glass which contained nickel in their structure frequently presented with inclusions in the form of nickel sulfide which, during the melting of the glass, formed and appeared as small invisible particles that were impossible to see with the naked eye once the glass was formed. These nickel sulfide inclusions, due to their high thermal expansion coefficient, can cause thermal tensions sufficient to fracture a plate of glass. This is especially a problem when the glass pieces are subjected to thermal treatment, such as tempering, in which the presence of nickel sulfide causes an excessively high incidence of breakage as a result of the tempering process.
An additional disadvantage of glass which contains nickel is the change in color which they are subject to after the thermal process, for instance after tempering.
U.S. Pat. No. 5,023,210 of Krumwide et al, issued on Jun. 11, 1991, describes a neutral, low transmission grey glass composition (the glass has a luminous transmission of less than 20%) which does not use nickel. In order to achieve characteristics similar to that of a neutral grey glass, Krumwide uses chromium oxide in quantities of 220 to 500 ppm of Cr2O3 in the composition, which in these proportions produces a grey tone and adjusts the levels of selenium and cobalt oxide to make the tone neutral. Nevertheless, in earlier references, there is mention that it is preferable to not use these compounds, due to problems that arise because of the difficulty in melting the chromium compounds (U.S. Pat. No. 4,837,206) and in addition, due to the fact that it is difficult to get rid of the solid materials that these compounds contain. Similarly, U.S. Pat. No. 5,308,805 mentions the problem of using chromium oxide as a coloring agent, since it requires the use of additional non-conventional operations and machinery within the furnaces, in order to obtain the necessary conditions to produce the desired glass.
U.S. Pat. No. 5,346,867, of Jones et al, granted on Sep. 13, 1994, describes a heat-absorbent glass composition, with a neutral gray color, which uses manganese and titanium oxide to increase the retention of selenium (which is a high-cost component) during the production process. The neutral grey glass with a control thickness of 4 mm, light transmission using A illuminant of 10.0% to 55.0%. Although from previous references (U.S. Pat. No. 4,873,206) we know that the use of manganese tends to form a yellowish-brown coloring when it is exposed to ultraviolet radiation, making it difficult to maintain uniformity in the product, and the use of titanium causes a yellowish coloring when the glass enters into contact with the molten tin from the floating process. This is what makes these two components undesirable during the glass production process, since coloring control is critical to obtaining the desired tone in manufacturing. Jones and others mention in their '867 patent that the solarization process is a phenomenon associated with the change from Fe3+ to Fe2+, which causes an undesirable change in the color; also they found that this does not happen in the glass described and additionally, the use of titanium oxide is incorporated into the glass to obtain the desired range of dominant wavelength, as well as to reduce the transmission of ultraviolet radiation.
Additionally, it is well known by people familiar with the art that the addition or substitution of one or more colorants by another or others, or a change in the relative proportion of the colorant in the composition of the glass, affects not only the color of the product, as for example the dominant wavelength of the color or the excitation purity, but also the light transmission, the heat absorption and other properties such as ultraviolet and infrared radiation transmission.
It is well known that copper has played an important role in the production of glass, ceramics and colored pigments. The coloring of Persian ceramics has been recognized, for example, for its tone conferred by copper. Of special interest to ceramic artists are turquoise blue and especially the Egyptian and Persian dark blue (Waldemar A. Weil; Colored Glasses, Society of Glass Technology, Great Britain, p. 154-167, 1967).
Copper has been used in glass compositions, not only in the silicate-sodium-calcium type, but in some others, such as those which contain for example borosilicate. Therefore, the color developed depends on the foundation of the glass, its concentration and its state of oxidation.
In the case of the glass referred to as the base, copper in oxide form provides a greenish tone of blue coloring, specifically turquoise; however, in glass, copper can be in its monovalent state, which does not impart color. Thus, the greenish blue hue depends not only on the quantity of copper present, but also on the ionic balance between the cupric and cuprous states. The maximum absorption of copper oxide is found in a spectrum centered around 780 ηm, and a weak maximum secondary peak is present at 450 ηm, which disappears at high soda contents (around 40% weight) (C.R Bamford, Color Generation and Control in Glass, Glass Science and Technology, Elsevier Scientific Publishing Company, p. 48-50, Amsterdam, 1977).
In the production of red ruby glass, a mixture containing copper oxide together with any reducer agent (SnO is commonly used), is melted in reduced conditions. The initial mixture shows the blue characteristic color of the copper II, but as soon as the melting begins, changes the color to a pale straw yellow which takes place during this stage. Due to a thermal treatment to a temperature between the annealing point and the softening point, the ruby red color is developed. If, during the melt, the reduction state is carried out beyond a critical stage, the color changes to brown and appears opaque or "turned off". On the other hand, if the copper is insufficiently reduced, some traces of blue color are kept and the ruby red color is not developed (Amal Paul, Chemistry of Glasses, Chapman and Hall, p. 264-270, London, 1982).
U.S. Pat. No. 2,922,720 of Parks and others, granted on Jun. 20, 1957, discusses the use of copper in glass: " . . . Copper has long been used as a coloring agent for glass-to develop a ruby coloration; but in order to obtain the desired effect in open or tank furnace melting, it has been necessary to use, in conjunction with the copper, cyanogens as reducing agents . . . ." It also mentions the effect of copper in the coloring of the glass as due to the colloidal suspension of metallic copper particles in the glass, and by analogy it is believed that a particle size produces ruby red coloring, with the intensity of the color depending on the concentration of copper. For smaller size particles, the color effect is null.
According to the above, this invention incorporates the use of erbium oxide as a decolorant to neutralize the greenish tone conferred by the iron oxide necessary to reduce solar transmission; in addition, the incorporation of titanium is intended to reduce UV transmission with the effect of moving the color toward yellowish tones. Finally, copper oxide is used to adjust the coloring given by the titanium and the oxides present in the iron. The incorporation of copper oxide confers a bluish tone, and the use of cobalt oxide, which has traditionally been used for this purpose, is avoided.
The erbium oxide has advantages over selenium, due to its chemical stability and the ease of dosing and control, as a non-volatile substance. In addition, the specific direction in which it acts on color is clearly favorable.
The study published in the Scientific Conference on Ceramics and Glass ("Jornadas Cientificas sobre ceramica y vidrio") leads us to the conclusion that erbium oxide is an excellent physical decolorizing agent for sodium-calcium-silicate glasses. Its conclusions were that a base glass of 0.03% Fe2O3 and 26% redox would require approximately 0.040% Er2O3, to achieve a satisfactory effect.
Alternatively, in some examples selenium is incorporated in order to complement the reddish coloring, which is necessary to adjust the green color.
Following on the above, a sodium-calcium-silicate base composition, comprised of: from 0.40 to 0.80% Fe2O3, 0.05 to 2.0% TiO2, 0.2 to 2.5% Er2O3, from 20 to 200 ppm of CuO; <10 ppm of Se; 0.0 to 0.1% carbon; and 15 to 50% ferrous (redox) has a light transmission of >65%, solar transmission (TS) <55%, ultraviolet transmission <40%, with color values of a*=−4 to 3, and b*=4 to −2.


A method for producing a ceramic honeycomb filter having a ceramic honeycomb structure having plugs in predetermined cells: comprising using an apparatus having a reservoir having an inlet for a plugging material slurry and an upper opening, a porous plate with pluralities of openings covering the upper opening of the reservoir, and a holding member fixed to an upper end of the reservoir; keeping a lower surface of the sealing film attached to a lower end surface of the ceramic honeycomb structure apart from an upper surface of the porous plate by a distance D of more than 0 mm and 2.0 mm or less; supplying a predetermined volume of the plugging material slurry into the reservoir to introduce it into the predetermined cells of the ceramic honeycomb structure; rotating the ceramic honeycomb structure after sealing of the ceramic honeycomb structure is released; and lifting the ceramic honeycomb structure after the rotation starts.

To remove carbon-based particulate matter from an exhaust gas discharged from diesel engines, ceramic honeycomb filters having ceramic honeycomb structures with flow paths alternately sealed at both ends has been used. As shown in FIGS. 12(a) and (b), a ceramic honeycomb filter 1 comprises a ceramic honeycomb structure 10 composed of pluralities of cells 13 partitioned by porous cell walls 12, and a peripheral wall 11; and plugs 14a, 14b alternately sealing both end portions 15a, 15b of cells 13 in a checkerboard pattern. The exhaust gas containing particulate matter flows into cells 13aopen on an inlet-side end surface 16a, passes through the cell walls 12, and then flows out of adjacent cells 13b open on an outlet-side end surface 16b, during which particulate matter in the exhaust gas is captured by fine pores (not shown) in the cell walls 12.
To form plugs 14a, 14b in both end portions 15a, 15b of cells 13 of the ceramic honeycomb structure 10, for example, the following method has been conventionally used. That is, sealing films 6 made of a resin, etc. are attached to both end surfaces 16a, 16b of the ceramic honeycomb structure 10 [FIG. 13(a)], and provided with penetrating pores 6a, 6b alternately at positions corresponding to open cells in a checkerboard pattern by laser beams [FIG. 13(b)], such that only one end portion of each cell 13 is sealed by the sealing films 6.
The end surface 16a of the ceramic honeycomb structure 10 is immersed in a plugging material slurry 40 containing ceramic powder and a dispersing medium in a vessel 90 [FIG. 13(c)], and pushed downward to a predetermined depth. The plugging material slurry 40 is introduced into the predetermined cells 13 through the penetrating pores 6a of the sealing film 6, to form plugs 14a of the predetermined length in the end portions 15a of the cells 13 at the end surface 16a [FIG. 13(d)].
The ceramic honeycomb structure 10 provided with the plugs 14a in one-side end portions 15a is taken out of the vessel 90 [FIG. 13(e)]. With the end surface 16b immersed upside down in the plugging material slurry 40, the ceramic honeycomb structure 10 is pushed downward to a predetermined depth, to form plugs 14b in a checkerboard pattern in the other-side end portions 15b of the cells 13 [FIG. 13(f)]. Finally, the ceramic honeycomb structure 10 provided with the plugs 14a, 14b in the end portions 15a, 15b is taken out of the vessel 90 [FIG. 13(g)].
The plugs 14a, 14b are dried and sintered, to obtain the ceramic honeycomb filter 1 having the plugs 14a, 14b in a checkerboard pattern in the end portions 15a, 15b of the cells 13.
In this conventional method, when the ceramic honeycomb structure 10 having a plugging material slurry 40 charged into its end portions is lifted from the vessel 90, the plugging material slurry 40 falls from the end portions, resulting in large unevenness in length of the resultant plugs. A plugging material slurry 40 may drop off from pluralities of cells 13, resulting in a certain area of cells 13 with no plugs. When the plugs in the ceramic honeycomb structure 10 are largely uneven in length, the cell walls filtering an exhaust gas also have largely uneven surface areas, providing a filter having unstable particulate-matter-capturing performance and pressure loss performance, and thus resulting in a defective ceramic honeycomb filter, which should be discarded.
To suppress such unevenness in length of the plugs, it is contemplated to slide a ceramic honeycomb structure 10 having a plugging material slurry 40 charged into its end portions horizontally when taken out of the vessel 90. However, this method not only requires an at least partially detachable vertical wall in the vessel 90, but also fails to conduct the formation of plugs continuously.
As a method for suppressing the unevenness in length of the plugs, JP 2008-55347 A discloses, as shown in FIG. 14, a plugging method comprising (a) using an apparatus comprising a vessel 100 composed of a vertically movable side wall 101 and a bottom 102; a device 110 for holding a ceramic honeycomb structure, which comprises a pressing member 104 attached to a vertically movable arm 103, and a gripping member 105, and a chuck member 120 for sealing a clearance between an opening of the vessel 100 and the gripping member 105 of the gripping device 110; (b) charging a plugging material slurry into the vessel 100; (c) setting the ceramic honeycomb structure 130 gripped by the gripping device 110 in the plugging material slurry in the vessel 100; (d) sealing the clearance of the vessel 100 with the chuck member 120; (e) lifting the bottom of the vessel 100 to introduce the plugging material slurry under pressure into cell end portions of the ceramic honeycomb structure, thereby forming plugs; (f) rotating the bottom 102 of the vessel 100 to separate the plugging material slurry filled in the cell end portions from a small amount of the plugging material slurry remaining on the bottom 102 of the vessel 100, thereby preventing the plugging material slurry in the cell end portions from being pulled back into the vessel 100; (g) moving the side wall 101 downward; and then (h) sliding the ceramic honeycomb structure 130 along the bottom 102 to take it out of the vessel 100.
In the method of JP 2008-55347 A, however, because the bottom 102 of the vessel 100 is rotated while the clearance of the vessel 100 is sealed with the chuck member 120, air does not intrude into the plugging material slurry, failing to easily separate the plugging material slurry even with a shear force. Although the rotation of the bottom 102 gives a shear force to the plugging material slurry, the shear force disappears while the side wall 101 is moved downward, failing to obtain the effect of rotating the ceramic honeycomb structure 130. It has been found that when the ceramic honeycomb structure 130 slides along the bottom 102, the plugging material slurry in the cell end portions is physically separated from that remaining on the bottom 102, making the rotation of the bottom 102 unnecessary.
Furthermore, because the method of JP 2008-55347 A is a batch-type process having many steps, it takes too much time. Particularly, because a batch of a plugging material slurry should be supplied to the vessel 100 after lifting the once-lowered side wall 101, and because a subsequent step should wait until a surface of the plugging material slurry in the vessel 100 becomes flat, large time loss is inevitable. In addition, if the next batch of a plugging material slurry were supplied with some plugging material slurry remaining on the side wall 101 and the bottom 102 of the vessel 100, the amount of the plugging material slurry in the vessel 100 would not be constant, resulting in large unevenness in length of plugs formed in the cells. The supplying of the next batch of a plugging material slurry after removing the plugging material slurry remaining on the side wall 101 and the bottom 102 of the vessel 100 would need additional time.
As a method for forming plugs having uniform length in open end portions of cells, JP 2009-6629 A discloses, as shown in FIG. 15, an apparatus for plugging a honeycomb structure, comprising a plugging material slurry reservoir 201, a plate 202 with pluralities of openings 203 disposed on the reservoir 201, an inlet 204 for supplying a plugging material slurry to the reservoir 201, a valve 205 disposed in the inlet 204, and a piston 206 for supplying the plugging material slurry under pressure through pluralities of openings 203 of the plate 202. Because the plugging apparatus has pluralities of openings 203, the plugging material slurry with high viscosity can pass through the openings 203 under pressure by the piston 206, thereby forming a plugging material slurry layer with uniform thickness on an upper surface of the plate 202. Therefore, a leveling process is not necessary after the plugging material slurry is supplied. By disposing a honeycomb structure 210, to which a sheet having openings corresponding to predetermined cells is attached, on the plugging material slurry layer on an upper surface of the plate 202, and then lifting the piston 206 toward the plate 202, the plugging material slurry is introduced under pressure into the predetermined cells to form plugs. Because the plate 202 has a flat surface, the honeycomb structure 210 can be easily horizontally moved on the plate 202 to be taken out of the plugging apparatus.
Because the honeycomb structure 210 horizontally moves on the plate 202, the apparatus of JP 2009-6629 A does not have such a problem that plugs are pulled back when the honeycomb structure 210 is taken out. However, when the plugging material slurry is introduced under pressure by the piston 206 into the honeycomb structure 210 disposed on the plate 202, the plugging material slurry leaks from a lower edge of an outer periphery of the honeycomb structure 210. JP 2009-6629 A does not describe any mechanism of preventing the leakage of a plugging material slurry. Because the honeycomb structure 210 provided with plugs is horizontally moved on the plate 202 to be taken out of the plugging apparatus, it is not easy to install a mechanism for preventing the leakage of the plugging material slurry on the plate 202. The leakage of a plugging material slurry leads to large unevenness in length of plugs in the resultant honeycomb structures 210, resulting in defective ceramic honeycomb filters, which should be discarded.
As shown in FIG. 16, JP 2004-25098 A discloses a method for producing a ceramic honeycomb filter, comprising the steps of (a) pressing a lower end surface of a ceramic honeycomb structure 301 having flow paths 303 partitioned by pluralities of cells 304 on a bottom surface of a vessel 309 containing a plugging material slurry 308, thereby introducing the plugging material slurry 308 under pressure into predetermined cells 304, to form plugs 302; (b) rotationally lifting the ceramic honeycomb structure 301 by a slight distance, to form an air layer 310 between the plugs 302 and the bottom surface of the vessel 309 to separate them; and then (c) taking the ceramic honeycomb structure 301 provided with the plugs 302 out of the vessel 309. In the method of JP 2004-25098 A, however, because the ceramic honeycomb structure 301 is rotationally lifted from a state where the lower end surface of the ceramic honeycomb structure 301 is in close contact with the bottom surface of the vessel 309, the plugging material slurry 308 left between the ceramic honeycomb structure 301 and the vessel 309 is decompressed, causing the plugs 302 in the cells 304 to be pulled back, resulting in unevenness in their lengths.
As shown in FIG. 17, JP 2008-55796 A discloses a method for plugging a ceramic honeycomb structure 486 by using an apparatus having an annular upper housing 463 communicating with an air inlet, an annular lower housing 464 connected to the upper housing 463, a movable housing 465 disposed in the annular upper housing 463 and the annular lower housing 464, which is inflatable by supplying an compressed air, an elastic body 467 contained in the upper housing 463, which is inflatable by supplying an compressed air, and a second elastic body 466 connected to a vessel; the method comprising gripping a ceramic honeycomb structure 486 with the movable housing 465 and the elastic body 467 inflated by an compressed air; and immersing the ceramic honeycomb structure 486 in slurry stored in the vessel. However, JP 2008-55796 A fails to teach or suggest a process of taking the ceramic honeycomb structure 486 provided with plugs out of the vessel. When the ceramic honeycomb structure 486 provided with plugs is lifted from the vessel without rotation, part of the plugged slurry is pulled back, resulting in unevenness in the length.

Method and apparatus for producing ceramic honeycomb filter


Hydrophobic metal nanoparticles are prepared by reducing a metal precursor in a non-polar or low polar organic solvent with or without volume expansion by adding CO2.

Silver nanoparticles (AgNPs) and other metal nanoparticles such as copper, and palladium have attracted considerable interest in many applications owning to their intrinsic size- and shape-dependent effects on antibacterial, catalytic, electronic, and optical properties. Sigma-Aldrich Inc. provides hydrophobic silver nanoparticles dispersed in hexane with two particle size distributions of 3-7 nm and 5-15 nm, respectively. The prices of both silver colloidals are about US$180 for a quantity of 25 ml. As considering the expensive prices, researchers are eager to develop a more economical technique to prepare the dispersion of hydrophobic metal nanoparticles, such as silver and palladium, in organic solvents.
The direct synthesis of silver organosol (silver nanoparticles dispersed in an organic solvent) is known to be a problem due to the poor solubility of traditional water-soluble silver salts such as silver nitrate (AgNO3), silver sulfate (Ag2SO4), silver oxide (Ag2O), and silver halides (AgX, X═F, Cl, Br, or I) in organic media. Similarly, the preparation of other metal nanoparticles including copper, palladium, gold, and platinum are also limited in their poor solubility of the corresponding metal salts in organic solvents. Consequently, the two-phase based methods were developed and adopted to prepare metal organosol by using phase transfer agents. Sarathy, K. V.; Raina, G.; Yadav, R. T.; Kulkarni, G. U.; Rao, C. N. R. in an article entitled "Thiol-derivatized nanocrystalline arrays of gold, silver, and platinum" J. Phys. Chem. B 1997, 101, 9876 describe the procedures involving the transfer of metal hydrosols (metal nanoparticles dispersed in water) into an organic solvent by using concentrated HCl as the phase transfer agent. Brust, M.; Walker, M.; Bethell, D.; Schiffrin, D. J.; Whyman, R. in an article entitled "Synthesis of thiol-derivatized gold nanoparticles in a 2-phase liquid-liquid system" J. Chem. Soc. Chem. Commun. 1994, 801 report the synthesis of gold nanoparticles by reducing the AuCl− ions with sodium borohydride in the water-toluene phase system. In their report, AuCl− ions was transferred from water phase into toluene phase using tetraoctylammonium bromide as the phase transfer agent. The disadvantages of aforementioned two-phase method were the necessity of toxic phase transfer agents such as concentrated HCl or tetraoctylammonium bromide, as well as the complicated synthetic process.
It is well-known that silver carboxylates with long alky chain are utilized as the silver source in the field of thermographic and photothermographic imaging techniques. In addition, the solventless approaches have been adopted to produce hydrophobic AgNPs through thermal decomposition of silver carboxylates with long alky chain under high temperature condition. For example, Abe, K.; Hanada, T.; Yoshida, Y.; Tanigaki, N.; Takiguchi, H.; Nagasawa, H.; Nakamoto, M.; Yamaguchi, T.; Yase, K. in an article entitled "Two-dimensional array of silver nanoparticles" employed the thermolysis of silver carboxylates with long alky chain (e.g., those containing 14-18 carbon atoms) to fabricate the hydrophobic silver nanoparticles at 250° C. in N2 atmosphere. Similar approaches are also described in Lee, S. J.; Han, S. W.; Choi, H. J.; Kim, K. J. Phys. Chem. B 2002, 106, 2892 and in Yang, N. J.; Aoki, K.; Nagasawa, H. J. Phys. Chem. B 2004, 108, 15027. However, the forementioned silver salts of carboxylic acid with long alky chains were not suitable to serve as the silver ion sources in wet chemical synthetic process due to their low solubility in water and organic solvents. Jacobson, C. A.; Holmes, A. in an article entitled "Solubility data for various salts of lauric, myristic, palmitic, and stearic acids" J. Biol. Chem. 1916, 25, 29 showed the results of low solubility of silver laurate, myristate, palmitate, and stearate in various solvents including water, alcohols, and ether. In addition, Malik, W. U.; Jain, A. K.; Jhamb, O. P. in an article entitled "Solutions of soaps in organic solvents" J. Chem. Soc. A 1971, 1514 investigated the low solubility of silver salts of carboxylic acid in various organic solvents. Therefore, the lack of organo-soluble metal precursors is the main impediment to the preparation of hydrophobic metal nanoparticles in wet chemical synthetic process. From this viewpoint, finding organo-soluble metal precursors is a key to provide the opportunity to synthesis metal nanoparticles directly in organic media.
The nontoxic, non-flammable, inexpensive, and abundant nature of carbon dioxide (CO2) has attracted great attention as an ideal processing medium in the fields of material science and nanotechnology (Eckert, C. A.; Knutson, B. L.; Debenedetti, P. G. Nature 1996, 383, 313; Holmes, J. D.; Lyons, D. M.; Ziegler, K. J. Chem.-Eur J. 2003, 9, 2144; Johnston, K. P.; Shah, P. S. Science 2004, 303, 482; Shah, P. S.; Hanrath, T.; Johnston, K. P.; Korgel, B. A. J. Phys. Chem. B 2004, 108, 9574). Metal nanoparticles, including silver and gold nanoparticles, have been synthesized through supercritical CO2 (sc-CO2) technologies such as the water-in-CO2 (w/c) microemulsions (Ji, M.; Chen, X. Y.; Wai, C. M.; Fulton, J. L. J. Am. Chem. Soc. 1999, 121, 2631; Ohde, H.; Hunt, F.; Wai, C. M. Chem. Mat. 2001, 13, 4130; McLeod, M. C.; McHenry, R. S.; Beckman, E. J.; Roberts, C. B. J. Phys. Chem. B 2003, 107, 2693), rapid expansion of supercritical solution into a liquid solvent (RESOLD) (Sun, Y. P.; Atorngitjawat, P.; Meziani, M. J. Langmuir 2001, 17, 5707; Meziani, M. J.; Pathak, P.; Beacham, F.; Allard, L. F.; Sun, Y. P. J. Supercrit. Fluids 2005, 34, 91), sc-CO2 flow process (McLeod, M. C.; Gale, W. F.; Roberts, C. B. Langmuir 2004, 20, 7078), arrested precipitation (Shah, P. S.; Husain, S.; Johnston, K. P.; Korgel, B. A. J. Phys. Chem. B 2001, 105, 9433; Shah, P. S.; Husain, S.; Johnston, K. P.; Korgel, B. A. J. Phys. Chem. B 2002, 106, 12178.), and other specific approaches (Fan, X.; McLeod, M. C.; Enick, R. M.; Roberts, C. B. Ind. Eng. Chem. Res. 2006, 45, 3343; Moisan, S.; Martinez, V.; Weisbecker, P.; Cansell, F.; Mecking, S.; Aymonier, C. J. Am. Chem. Soc. 2007, 129, 10602; Esumi, K.; Sarashina, S.; Yoshimura, T. Langmuir 2004, 20, 5189). However, sc-CO2 is a poor solvent for many high molecular weight and polar compounds due to the low dielectric constant and polarizability per volume of CO2. Accordingly, CO2-philic fluorinated molecules including surfactants, capping ligands, and metal precursors are required in the prior art to enhance the solubility of compounds in sc-CO2, although they are economically and environmentally unfavorable. Besides, a quite high process pressure (generally over 100 bar) is required to dissolve adequate amount of the fluorinated reagents in compressed CO2.
Recently, a non-fluorinated agent having branched alky chains, isostearic acid (2,2,4,8,10,10-Hexamethylundecane-5-carboxylic acid), is successfully employed to disperse silver nanoparticles in scCO2. Bell, P. W.; Amand, M., Fan, X.; Enick, R. M.; Roberts, C. B. in an article entitled "Stable dispersions of silver nanoparticles in carbon dioxide with fluorine-free ligands" Langmuir 2005, 21, 11608 disclose the successful dispersion of isostearic acid-capped silver nanoparticles in high pressure (276 bar) CO2 or in CO2 with 10 vol % hexane as cosolvent. In their article, silver nanoparticles were synthesized within the cores of AOT reverse micelles in advance. AOT (sodium bis(2-ethylhexyl) sulfocuccinate) was utilized as the surfactant to form micelles with nanosized reaction space in aqueous medium. While silver nanoparticles were formed in the reverse micelles, isostearic acid was added to replace the AOT as the capping agent on the surface of the silver nanoparticles. Then, the authors successfully dispersed the isostearic acid-capped silver nanoparticles in compressed CO2. Anand, M.; Bell, P. W.; Fan, X.; Enick, R. M.; Roberts, C. B. in an article entitled "Synthesis and steric stabilization of silver nanoparticles in neat carbon dioxide solvent using fluorine-free compounds" J. Phys. Chem. B 2006, 110, 14693 disclose the in-situ synthesis of silver nanoparticles in the presence of isostearic acid in compressed CO2 wherein silver bis(3,5,5-trimethyl-1-hexyl) sulfosuccinate (Ag-AOT-TMH) was reduced to form silver nanoparticles at high pressure. Based on the results of two aforementioned articles, the authors suggested that the branched alky chain in isostearic acid is the key to afford the sufficient solvent-ligand interactions between silver nanoparticles and CO2. Thus, silver nanoparticles were able to be stably dispersed in CO2. However, the main drawback in their methods is the necessity of high pressure (207 bar) and cosolvent (cyclohexane) in order to improve the solvent strength of CO2 and the dispersibility of silver nanoparticles.
Instead of using scCO2 as a reaction medium, CO2-expanded liquids (CXLs) form a new class of tunable solvents for chemical syntheses. Jessop, P. G; Subramaniam, B. in an article entitled "Gas-expanded liquids" Chem. Rev. 2007, 107, 2666 describe CXLs are the mixtures where the compressed CO2 are dissolved into organic solvents accompanying volume expansion of the solutions. As compared to scCO2, CXLs are benefited by the milder operating pressure (tens of bar). Kordikowski, A.; Schenk, A. P.; VanNielen, R. M.; Peters, C. J. in an article entitled "Volume expansions and vapor-liquid equilibria of binary mixtures of a variety of polar solvents and certain near-critical solvents" J. Supercrit. Fluids 1995, 8, 205 disclose the volume expansion of organic solvents was 500% higher than by dissolving CO2 under mild pressure ranging from 40 to 70 bar. Therefore, the physicochemical properties of CXLs, including density, viscosity, solute diffusivity, and gas solubility can be adjusted easily by dissolving various amount of CO2 into organic solvents (Yin, J. Z.; Tan, C. S. Fluid Phase Equilib. 2006, 242, 111; Lin, I. H.; Tan, C. S. J. Chem. Eng. Data 2008, 53, 1886; Lin, I. H.; Tan, C. S. J. Supercrit. Fluids 2008, 46, 112, Lopez-Castillo, Z. K.; Aki, S. N. V. K.; Stadtherr, M. A.; Brennecke, J. F. Ind. Eng. Chem. Res. 2008, 47, 570; Xie, Z. Z.; Snavely, W. K.; Scurto, A. M.; Subramaniam, B. J. Chem. Eng. Data 2009, 54, 1633). Moreover, Tan's group showed that the diffusivity of solutes as well as H2 solubility could be enhanced in CXLs. (Yin, J. Z.; Tan, C. S. Fluid Phase Equilib. 2006, 242, 111; Lin, I. H.; Tan, C. S. J. Chem. Eng. Data 2008, 53, 1886; Lin, I. H.; Tan, C. S. J. Supercrit. Fluids 2008, 46, 112). Bogel-Lukasik, E.; Fonseca, I.; Bogel-Lukasik, R.; Tarasenko, Y. A.; da Ponte, M. N.; Paiva, A.; Brunner, G. in an article entitled "Phase equilibrium-driven selective hydrogenation of limonene in high-pressure carbon dioxide" reported that the hydrogenation rate of limonene in CXLs became faster compared to the pure H2 system without adding CO2. Therefore, the decrease of solution viscosity, increase of solute diffusivity, and higher H2 solubility are beneficial to improve the mass transport as well as chemical syntheses in CXLs. On the other hand, dissolving CO2 can weaken the solvating power of solvents and the precipitation of solutes is triggered in CXLs. Based on these phenomena, various methods such as gas antisolvent precipitation (GAS), precipitation with compressed antisolvent (PCA), supercritical antisolvent (SAS), solution enhanced dispersion by supercritical fluids (SEDS), and depressurization of an expanded liquid organic solution (DELOS) were adopted to precipitate fine particles composed of inorganic compounds, organic compounds, explosives, pharmaceuticals, and polymers (Jung, J.; Perrut, M. J. Supercrit. Fluids 2001, 20, 179; Shariati, A.; Peters, C. J. Curr Opin. Solid State Mat. Sci. 2003, 7, 371; Yeo, S. D.; Kiran, E. J. Supercrit. Fluids 2005, 34, 287). Recently, the deposition process of ligand-capped metal nanoparticles is applied to accomplish the uniform wide-area nanoparticle films and size-selection fractionation in CXLs (McLeod, M. C.; Anand, M.; Kitchens, C. L.; Roberts, C. B. Nano Lett. 2005, 5, 461; McLeod, M. C.; Kitchens, C. L.; Roberts, C. B. Langmuir 2005, 21, 2414; U.S. Pat. No. 7,384,879). In spite of these various merits in the field of material science and nanotechnology, however, applying CXLs as process medium to synthesize hydrophobic metal nanoparticles such as silver and palladium have not been reported to date. In order to take advantage of CXLs, an organo-soluble and fluorine-free metal precursor is also required to provide metal ions in organic medium.

Methods for preparing hydrophobic metal nanoparticles and precursors used therein


Microfluidic systems and devices having integrated fluidic impedances are provided. Such impedances hinder the passage of fluid at low differential pressures, but allow fluid flow at higher differential pressures. Impedances are formed at the overlap of two or more microfluidic channels contained in different layers of a device. Such devices can be rapidly prototyped and can be assembled to contain multiple fluidic impedances to perform complex fluid handling tasks, including the metering of small aliquots from a larger fluid volume. Various means may be used to overcome the fluidic impedances.

The present invention relates to microfluidic devices and the control of fluid flow within those devices. These devices are useful in various biological and chemical systems, as well as in combination with other liquid-distribution devices.
There has been a growing interest in the manufacture and use of microfluidic systems for the acquisition of chemical and biological information. In particular, microfluidic systems allow complicated biochemical reactions to be carried out using very small volumes of liquid. These miniaturized systems exhibit improve response time of reactions, minimize sample volume, and lower reagent usage.
Traditionally, these microfluidic systems have been constructed in a planar fashion using silicon fabrication industry techniques. Representative systems are described, for example, in some early work by Manz et al. (Trends in Anal. Chem. (1990) 10(5): 144-149; Advances in Chromatography (1993) 33: 1-66). These publications show microfluidic devices constructed using photolithography to define channels on silicon or glass substrates and etching techniques to remove material from the substrate to form the channels. A cover plate is bonded to the top of the devices to provide closure.
More recently, a number of methods have been developed that allow microfluidic devices to be constructed from plastic, silicone or other polymeric materials. In one such method, a negative mold is first constructed, and plastic or silicone is then poured into or over the mold. The mold can be constructed using a silicon wafer (see, e.g., Duffy et al., Analytical Chemistry (1998) 70: 4974-4984; McCormick et al., Analytical Chemistry (1997) 69: 2626-2630), or by building a traditional injection molding cavity for plastic devices. Some molding facilities have developed techniques to construct extremely small molds. Components constructed using a lithography, electroplating and molding (LIGA) technique have been developed at the Karolsruhe Nuclear Research center in Germany (see, e.g., Schomburg et al., Journal of Micromechanical Microengineering (1994) 4:186-191), and commercialized by MicroParts (Dortmund, Germany). Jenoptik (Jena, Germany) also uses LIGA and a hot-embossing technique. Imprinting methods in PMMA also have been demonstrated (see, Martynova et al., Analytical Chemistry (1997) 69: 4783-4789). However, these techniques do not lend themselves to rapid prototyping and manufacturing flexibility. Additionally, these techniques are limited to planar structures. Moreover, the tool-up costs for both of these techniques are quite high and can be cost-prohibitive.
Traditionally, fluid manipulation in these fluidic systems is controlled by electrokinetic and/or electrophoretic transport. These techniques involve the use of voltages and currents to control fluidic movement. Electrodes are placed within the channels and sufficient voltage is applied to cause the hydrolysis of water within the device. This hydrolysis produces a charge gradient throughout the channels that causes either fluid to flow, or molecules within the fluid to move. These techniques have numerous problems including, but not limited to, the need for metallic electrodes within the chambers, connection of these electrodes to an outside voltage/current source, and the need for this source. Additionally, the hydrolysis of water often causes the formation of bubbles and radicals, which may have adverse effects on the devices or reactions occurring within the device.
Accordingly, there is a need for microfluidic devices capable of controlled fluid transport without requiring the use of current and voltage.
The present invention provides microfluidic devices that can control fluid flow. In one embodiment, such microfluidic devices can be rapidly prototyped with minimal tool-up costs, can be easily manufactured at low cost, and are robust.
The microfluidic devices contain fluidic impedances that can control fluid flow. The devices can accommodate the use of a vast array of liquid reagents or solutions including, but not limited to, aqueous solutions and organic solutions. The microfluidic devices of the present invention can be constructed using a variety of manufacturing techniques.
In one embodiment, a device consists of two or more microfluidic channels that are located on different layers of a three dimensional device. The channels are overlapped in certain areas in order to create fluidic impedances. Fluidic impedances hinder fluid flow through the device. The shape and the amount of overlap in the impedances can be controlled in order to alter the differential pressure necessary to cause fluid to flow through the impedances. In a preferred embodiment, a microfluidic device is formed from stencil layers through which channels have been cut, and the layered stencils are held together with adhesives.
In other embodiments, microfluidic impedances can be incorporated into devices constructed using other techniques. In one embodiment, microfluidic impedances are designed into a solid microfluidic device that is constructed using molding technology. In other embodiments, microfluidic impedances are incorporated into devices constructed using etching techniques usually associated with semiconductor processing. These devices can be constructed from etched silicon, glass, or other materials. Microfluidic impedances can be incorporated into devices constructed using still other techniques as well.
In certain embodiments, a microfluidic device contains one or more of these fluidic impedances. In certain embodiments, all of the fluidic impedances are substantially identical. In other embodiments, the impedances differ within a single device.
The term xe2x80x9cchannelxe2x80x9d as used herein is to be interpreted in a broad sense. Thus, it is not intended to be restricted to elongated configurations where the transverse or longitudinal dimension greatly exceeds the diameter or cross-sectional dimension. Rather, the term xe2x80x9cchannelxe2x80x9d is meant to comprise cavities or tunnels of any desired shape or configuration through which liquids may be directed. Such a fluid cavity may, for example, comprise a flow-through cell where fluid is to be continually passed or, alternatively, a chamber for holding a specified, discrete amount of fluid for a specified amount of time. xe2x80x9cChannelsxe2x80x9d may be filled with a material that allows fluid flow through the channel, or may contain internal structures comprising valves or equivalent components. A channel as used herein typically has a smallest dimension that is at least about 1 micron but is less than about 500 microns.
The term xe2x80x9cmicrofluidicxe2x80x9d as used herein is to be understood to refer to structures or devices through which a fluid is capable of being passed or directed, wherein one or more of the dimensions is less than about 500 microns.
The microfluidic devices described herein are xe2x80x9cgenericxe2x80x9d in that they are modular and can be easily reconfigured into or adapted to any design. In addition, these devices are capable of being used with a variety of pumping and valving mechanisms, including pressure, peristaltic pumping, electrokinetic flow, electrophoresis, vacuum and the like. In addition, the microfluidic devices of the present invention are capable of being used in collaboration with optical detection (e.g., fluorescence, phosphorescence, luminescence, absorbance and colorimetry), electrochemical detection, and any of various suitable detection methods. Suitable detection methods will depend on the geometry and composition of the device. The choice of such detection methods will be within the purview of the skilled artisan.
The term xe2x80x9cmicrofluidic impedancexe2x80x9d as used herein is to be understood to refer to a structure within a microfluidic device that hinders fluid flow. These devices are not limited to the particular shapes, geometries and materials provided herein.
The terms xe2x80x9cpositive pressurexe2x80x9d and xe2x80x9cnegative pressurexe2x80x9d as used herein refer to pressures differing from a reference pressure. A preferred reference pressure is atmospheric pressure.

Microfluidic systems with inter-channel impedances


The disclosure concerns controlling circuitry operably connectable to a plurality of constituent analog-to-digital converters (sub-ADCs) of an asynchronous time-interleaved analog-to-digital converter (TI-ADC). The controlling circuitry is configured to maintain a set of a number of sub-ADCs currently available for processing of an input sample, wherein the set is a subset of the plurality. Maintenance of the set is achieved by reception, from each of one or more of the sub-ADCs of the plurality, of an availability signal indicative of availability of the corresponding sub-ADC, and (responsive to the reception of the availability signal) addition of the corresponding sub-ADC to the set. Maintenance of the set is further achieved by (for each new input sample) selection of a sub-ADC of the set for processing of the new input sample, and (responsive to the selection) removal of the selected sub-ADC from the set and causing of the selected sub-ADC to process the new input sample. Corresponding TI-ADC, wireless communication receiver, wireless communication node, method and computer program product are also disclosed.

There is a strong trend in wireless communication to use ever-increasing bandwidth. This trend poses more and more stringent requirements on wireless transceivers, including analog-to-digital converters (ADCs) comprised therein.
Time interleaving is a powerful ADC technique for achieving high bandwidth operation with attractive power consumption. In a time-interleaved analog-to-digital converter (TI-ADC), a plurality of lower speed sub-ADCs (which may also be referred to as constituent ADCs) are used in parallel in a time interleaved fashion. Thus, when M sub-ADCs are used for processing respective samples, each sub-ADC only needs to process every Mth sample and the speed requirement of each sub-ADC is then relaxed by a factor M compared to a non-TI-ADC.
A drawback of the TI-ADC technique is that—unless the sub-ADCs are exactly identical—output imperfections will occur due to mismatch between the sub-ADCs as exemplified in the following. If the sub-ADCs have different direct current (DC) offsets, a fixed pattern of spurious tones equidistant in frequency will result. If the sub-ADCs have different gain and/or if there are sampling time errors, a signal dependent distortion will occur.
Calibration techniques exist that can, at least to some extent, correct for this type of errors. It is typically desirable that the calibration is fast and reliable, that it entails low cost and power overhead, and that it can be performed in the background of ADC operation without introducing disturbances. There is a need for improvements in many of these aspects.
An approach to mitigation of sub-ADC mismatch effects (that can be used as an alternative to, or in combination with, calibration techniques) is application of N redundant sub-ADCs (i.e., there being M+N sub-ADCs in total). Then, for each sample ready for conversion there are two or more (N+1) sub-ADCs available for the conversion—one of which is selected and used. This is in contrast to the conventional TI-ADC with M sub-ADCs, where, for each sample ready for conversion, there is only one sub-ADC available for the conversion. By making the selection among the available N+1 sub-ADCs random (or pseudo-random), the imperfections (e.g., spurious tones) will not appear according to a deterministic pattern (e.g., in time and/or frequency), but will rather be experienced as—possibly white—noise. The presence of noise may be more favorable than patterned imperfections in many applications, and for wireless communication (e.g., cellular) applications in particular.
An example of a time-interleaved ADC where randomization of the time-interleaved converters is applied can be found in U.S. Pat. No. 9,793,910 B1.
There is a need for improved approaches for time-interleaved analog-to-digital converters. Such approaches may, for example, aim at mitigating imperfections due to mismatch and/or solving problems related to resource management and usage.

Control of a time-interleaved analog-to-digital converter


A mobile weighing system for use on a truck or trailer to weigh a load carried by the truck or trailer. A load support frame supports a load and is positioned over the frame of the truck or trailer. A plurality of weighing cells are mounted over the truck or trailer frame in such a manner as to bear an approximately even distribution of the load. Each weighing cell comprises a lifting mechanism having an extended position and a rest position, a vertically disposed tension load cell and a linkage assembly coupling the lifting mechanism and the load cell to cause an upward force on a top end of the load cell when the lifting mechanism is extended. The bottom end of the load cell is attached to the support frame so that the support frame is suspended by the load cells when the lifting mechanisms are extended. The lifting mechanisms and linkage assemblies of the weighing cells are attached to the truck or trailer frame. A lock down mechanism integral to the load cells secures the load support frame when the lifting mechanism is in a rest position.

Truck and trailer loads are frequently weighed during the course of transporting such loads. Typically this is done using weighing apparatus which operates while the load remains in position on the truck or trailer. Therefore, to be effective the weighing apparatus must be mobile and easy to use and install. It must also provide an accurate measurement of the weight of the load and be able to account for, or eliminate, certain factors which would affect the accuracy of the measurement such as an angled positioning of the load (e.g. if the truck or trailer rests upon uneven ground at the time the measurement is taken).
Many weighing systems are in use in the marketplace but none provide the ease of operation, convenient mobility and broad-based effectiveness of the present invention which is described and claimed herein.


In an internal combustion engine having a system for utilizing the waste heat from the internal combustion engine via the Clausius-Rankine cycle, a system includes a circuit having lines with a working medium, a working medium pump, a vaporizer-exhaust gas heat exchanger, and a vaporizer-EGR heat exchanger, an expander, and a condenser for liquefying the vaporous working medium. The line for the working medium is run from the condenser to the vaporizer-EGR heat exchanger so that the working medium, after flowing through the condenser, first flows through the vaporizer-EGR heat exchanger, and the line for the working medium is run from the vaporizer-EGR heat exchanger to the vaporizer-exhaust gas heat exchanger so that the working medium, after flowing through the vaporizer-EGR heat exchanger, first flows through the vaporizer-exhaust gas heat exchanger.

Internal combustion engines are used in various technical applications for converting thermal energy into mechanical energy. In motor vehicles, especially in trucks, internal combustion engines are used to move the motor vehicle. The efficiency of internal combustion engines can be increased by the use of systems for utilizing the waste heat from the internal combustion engine by means of the Clausius-Rankine cycle process. In this process, the system converts the waste heat from the internal combustion engine into mechanical energy. The system comprises a circuit having lines with a working medium, e.g., water, a working medium pump for delivering the working medium, a vaporizer for vaporizing the liquid working medium, an expander, a condenser for liquefying the vaporous working medium, and a collecting and equalizing tank for the liquid working medium. By the use of such systems in the internal combustion engine, the overall efficiency of the internal combustion engine can be increased with such a system as a component of the internal combustion engine.
In this regard, a vaporizer-exhaust gas heat exchanger and a vaporizer-exhaust gas recirculation [EGR] heat exchanger are used in motor vehicles as a vaporizer for heating and vaporizing the working medium. The exhaust gas passed through the vaporizer-exhaust gas heat exchanger comes from an exhaust gas turbine as a main exhaust stream and the exhaust gas passed through the vaporizer-EGR heat exchanger comes from an exhaust gas recirculation line and after passage through the vaporizer-EGR heat exchanger is again supplied to the internal combustion engine in that the exhaust gas is introduced into a charge air line. To achieve a Clausius-Rankine cycle process efficiency as high as possible, it is necessary to heat, vaporize, and superheat the working medium to as high a temperature as possible. From the thermodynamic standpoint, it is therefore expedient to pass the exhaust gas, discharged from the condenser, first through the vaporizer-exhaust gas heat exchanger and then through the vaporizer-EGR heat exchanger. In so doing, the exhaust gas passed through the vaporizer-exhaust gas heat exchanger has lower temperatures than the exhaust gas passed through the vaporizer-EGR heat exchanger. For example, the exhaust gas passed through the vaporizer-exhaust gas heat exchanger has a temperature of 280° C. to 380° C. and the exhaust gas passed through the vaporizer-EGR heat exchanger has a temperature in the range of 500° C. to 700° C. As a result, the working medium can be first heated and at least partially vaporized in the vaporizer-exhaust gas heat exchanger and then completely vaporized and superheated in the vaporizer-EGR heat exchanger. As a departure from this, it is also known to pass the working medium after it is discharged from the condenser first partially through the vaporizer-EGR heat exchanger, then to pass the working medium, partially passed through the vaporizer-EGR heat exchanger, through the vaporizer-exhaust gas heat exchanger, and then to pass the working medium, passed through the vaporizer-exhaust gas heat exchanger, through the vaporizer-EGR heat exchanger. Moreover, it is also known to connect in parallel the vaporizer-exhaust gas heat exchanger and the vaporizer-EGR heat exchanger relative to the fluid stream with the working medium after discharge from the condenser.
Greatly increased temperatures occur at the vaporizer-EGR heat exchanger at the exhaust gas inlet side and this leads to high thermal expansions and damage of the vaporizer-EGR heat exchanger. The high temperatures in the vaporizer-EGR heat exchanger lead to a nonhomogeneous distribution of the working medium and thereby to a local dry-out in the individual regions of the vaporizer-EGR heat exchanger. The result is very high local temperatures, so-called hot spots, which may lead to decreased performance. When ethanol or organic working media of the Clausius-Rankine cycle process are used, the hot spots lead to degradations because wall temperatures above 400° C. may occur here. Lubricating oil as well, which is present in the working medium for lubricating the expander, can be degraded by the high temperatures in the vaporizer-EGR heat exchanger.


A network storage system for providing many clients with file services is structured to enable layered management of clients. A client management device is disposed between each client and a network file device provided with a disk unit. The network file device allocates a disk area to the client management device, and sets and manages access privileges of the client management device. The client management device allocates a disk area to each clients and sets and manages the access privileges of each client.

1. Field of the Invention
The present invention relates to a method for managing clients of a network storage system efficiently.
2. Description of Related Art
In recent years, storages have been expanded in capacity and reduced in price. Especially, with the progress of the techniques related to magnetic disks for realizing high recording density, it is about to be realized that one housing of storage comes to have a capacity of several tens of terabytes, which has been impossible so far.
On the other hand, networks have also been enhanced. In recent years, there have appeared even low priced networks that realize transfer rates of one gigabits/sec to 10 gigabits/sec. Conventional networks have been limited in transfer rate just within 10 megabits/sec to 100 megabits/sec, so that it has been difficult to build up an efficient system for transferring mass of data; the conventional system transfer performance is often degraded significantly when many users attempt to access a network concurrently. However, it cannot be impossible to build up a system that meets such requirements with use of a network of which transfer rate is one gigabits/sec to 10 gigabits/sec.
Under such circumstances, much attention is paid now to a network storage system, which is connected to a network and the users (clients) of the system are permitted to access the data stored in a common storage through the network. For example, JP-A No. 196961/2002 discloses a configuration of such a network storage system. In that system, a network connecting part, a server processing part, and a disk unit are disposed in the same housing. Each client accesses the common storage through the network using a communication method provided from the server, thereby the clients can input/output data stored in the server connected to the network as if the data is stored in itself.
One of the problems that must be solved with respect to such network storage systems that are getting to be expanded in scale is how to manage the storages. As a storage is expanded in scale, the method for managing the performance and its clients comes to be complicated. For example, JP-A No. 132455/2002 discloses such a method for managing a large-scale storage. According to the method, a large-scale memory unit for caching clients' data is connected to a subject network. This method is often employed to solve problems that might occur when in realizing of large scale high performance storages. On the other hand, JP-A No. 67187/2001 discloses a method for managing clients. The method enables a few managers to manage clients of storages disposed in a single housing.
A small scale storage can be managed by a few managers, since the number of clients is small. In the case of a large scale magnetic disk, however, the total capacity of one storage housing often becomes several tens of terabytes. In such a case, it is expected that the number of clients becomes several thousands to several tens of thousands. Management of clients mentioned here means allocating a storage area to each client and setting an access privilege for the client with respect to the allocated area. For example, each client comes to have a network (IP) address, a disk area name (/user/a), an access privilege (to read/write data from/to the allocated disk area), etc. set for the client. If such a client moves, the setting of the client must be updated.


A packaging container that can be easily disassembled is provided at low cost. The packaging container is formed by a laminate including a base layer being folded into a box shape and each end thereof being overlapped to be sealed with each other, the laminate having a fragile part formed thereon. The laminate further has, for example, a film layer, and includes, as a fragile part, a first scored part formed on a base layer and a second scored part formed on a film in a 2.0-mm-wide band area with the first scored part being a widthwise center.

Liquid paper containers for food and non-food liquid content, typically milk, are widely used. These containers use paper as a base material and made of a laminate in which a thermoplastic resin sealant layer is provided on an inner surface thereof. Liquid paper containers are also widely used for liquid food products such as fruit and other kinds of juice beverages, tea, coffee, milk, and soup, and alcoholic beverages such as sake (rice wine) and shochu (distilled spirit).
Some of these liquid paper containers are constituted by a paper base material and a sealant layer, but others have a gas barrier layer by use of an aluminum foil, a metal-deposited film, a metal-oxide-deposited film or other types between the paper layer and the sealant layer, or have a layer with gas barrier properties, such as an inorganic-compound-deposited film (see, for example, PTL 1).
Paper containers are widely used by virtue of their convenience and economy, and are common as packaging containers for various products. In recent years, containers are required to be less voluminous when they are disposed of from the viewpoint of environmental conservation. In addition, there is a change in consumers' awareness, as demonstrated by the fact that a mechanism for recycling the containers as a resource is being established. Under such circumstances, for example, used milk cartons are disassembled by consumers for recycling before being placed on a sorting collection route. In addition, even containers that are not collected for recycling are often disassembled and made less voluminous before being disposed of.
However, there is a problem at a time of actual disassembly of the containers. For a liquid paper container provided with a spout on the roof plate of a gable-roof-shaped top part, for example, there is practically no other choice but to open the top sealing part and cut around the spout with scissors or the like to take the spout off for disposal because the spout is firmly welded.
Furthermore, in the conventional liquid paper container described above, the top sealing part is firmly sealed by thermal fusion, which on occasions forces people to struggle to open the top sealing part by hand to disassemble the container after the container is emptied.
This is because the top sealing part of the liquid paper container is sealed with a bent laminate being abutted, which is likely to allow a gap, so that a highly flowable polyethylene resin is used on a sealant layer on the rear surface of the liquid paper container and sealed with a high temperature and a strong pressing force so as to fill and completely seal the gap.
Such circumstances are the reasons for the firm sealing. Lowering the sealing temperature or weakening the pressing pressure to reduce the sealing strength may possibly result in incomplete sealing, which may in turn cause a liquid leakage.
Rather than opening the top sealing part, cutting an opening of a spout with scissors can also disassemble an empty container, but cutting a hard spout or its surroundings with scissors accompanies significant trouble and is cumbersome because the method requires a tool, and therefore are not practiced commonly.
An improvement to this situation is a liquid paper container that allows a side plate of the body part thereof to be cut and torn to trigger easy disassembly.
For example, PTL 2 discloses a liquid paper container where both ends of a composite sheet provided with a synthetic resin layer on the front and rear sides of a paper layer are overlapped with each other, and a pull tab is provided at an end of the composite sheet on the outer surface side of a sealed part for bonding the body part, the pull tab being peelably provided via a peeling layer of a easily peelable tape-like film. This tape-like film is provided continuously along an inner surface of a four-side surface plate, and has a cutting line, such as a cut line, a half cut line, and a perforated line, engraved on a paper layer of the composite sheet along both widthwise edges of the tape-like film.
This proposed liquid paper container in PTL 2, however, requires an easily peelable tape-like film and poses a risk that the sealing on the body sealing of the part for bonding the body part weakens due to the peelability of the tape-like film. Thus there is a demand for further improvement in ease of disassembly of a used container or for another method that simplifies disassembling thereof.


A venturi apparatus comprises: a liquid-receiving section configured to be open to the atmosphere and to receive liquid through an opening at a first end, and having a second end through which the liquid can exit, the second end having a second cross-sectional area that is smaller than a first cross-sectional area of the first end; and a mixing section defining: an intermediate passageway configured to receive the liquid exiting from the liquid-receiving section, the intermediate passageway having a third cross-sectional area that is greater than the second cross-sectional area; and at least one side passageway extending from the intermediate passageway to a perimeter of the venturi apparatus to fluidly connect the intermediate passageway to the atmosphere to allow atmospheric gases to be drawn into the intermediate passageway to mix with the liquid when the liquid flows through the intermediate passageway.

The present invention is directed to an improved venturi device, and more particularly, an improved venturi device that is operative to facilitate the mixture of two or more fluids.
Venturi-type devices are well-known in the art. Generally, such devices comprise fittings or tubular structures, and in particular pipe structures, that are constricted in the middle and flared on both ends. When a fluid, such as a gas or liquid, is passed through the venturi, the fluid's velocity of flow is caused to increase whereas the fluid's pressure is correspondingly caused to decrease. Such devices are used in a variety of applications, and especially in measuring fluid flow or for creating suction as for driving aircraft instruments or drawing fuel into the flow stream of a carburetor.
Along these lines, venturi devices are frequently utilized to mix or combine a second fluid (i.e., a liquid or gas) with a fluid passing through the venturi. In this regard, it is well-known that the constriction point of the venturi creates a vacuum that is operative to draw in a liquid or gas. Exemplary of such devices that rely on this principle include those disclosed in U.S. Pat. Nos. 5,509,349 to Anderson, et al., and 6,568,660 to Flanbaum, the teachings of each of which are incorporated by reference.
Despite the well-known principals behind venturi devices, as well as the ability of the same to effectively and selectively facilitate the mixture of two or more fluids, drawbacks currently exist in relation to the inability of such devices to introduce (i.e., draw in) a second fluid to a first fluid passing through the venturi device. In this regard, the velocity of the first or primary fluid passing through the venturi is maximized at the point of tapering, which gives rise to the vacuum enabling the second fluid to be drawn into the fluid flow. However, the venturi's tapered portion, because of its limited size, is operative to reduce the area into which a second fluid can be drawn into the fluid flow. The combined increased speed of the fluid and reduced area can thus preclude the ability of the venturi to draw in a second fluid.
While attempts in the art have been made to facilitate the interaction or mixing between two fluids mixed with one another using a vertical flow effect, such as the fluid mixtures disclosed in U.S. Pat. No. 6,581,856 to Srinath, incorporated herein by reference, these attempts have failed insofar as those types of devices are designed to introduce a second fluid into a first stream of fluid emitted under pressure at high velocity. By virtue of the effects of high pressure and velocity, the ability to interject a second fluid becomes substantially more difficult and often requires that the second fluid itself be forcibly introduced under pressure.
Accordingly, there is a substantial need in the art for an improved venturi apparatus that modifies the desired flow dynamics of the venturi apparatus to consequently improve the ability of a first fluid passing through the venturi to draw in one or more second fluids such that a resultant mixture is produced having substantially greater homogeneity than conventional venturi devices. There is likewise a need in the art for such a venturi apparatus that is of simple construction, low cost to design and capable of being readily deployed in a wide-variety of applications. There is yet further need for such a device that can be readily utilized with a low or high pressurized fluid flow, as well as for facilitating the mixture of any combination of fluid materials, whether liquid with liquid, gas with liquid or gas with gas combinations.