Title of Invention: Liner retainer assembly
Abstract: The liner retainer assembly includes a cylinder that is mounted on a module of the fluid end of a pump. The cylinder has an aperture for receiving a liner and a retaining piston. A retaining nut is secured on the end of the retaining piston and engages one end of the liner. The retaining piston forms a fluid cavity and a spring cavity within the cylinder. The spring cavity houses a plurality of springs which bias the piston, retaining member, and liner towards the module, thus providing a resilient securing force. The fluid cavity communicates with a supply of hydraulic fluid for biasing the piston away from the module to relieve the springs. By pressurizing the fluid cavity, the springs are compressed to disengage the retaining member from the liner and allow the unthreading of the retaining member and then the removal of the liner.
Detailed Description: Part PAC: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Part PAR: Referring first to FIGS. 1 and 2, there is shown a fluid end module 10 and a cradle 28 of the pump power end. The pump is of the type used to pump fluids, such as drilling muds, cement or the like. Pumps of this type are well known. A wear plate 14 defines a bore 16 which leads into liner 20. The module 10 is used for the transfer of fluid from the suction manifold and suction module (not shown) to the discharge manifold (not shown) and discharge module.
Part PAR_2: An exemplary liner retaining flange assembly 18 of the present invention is used to secure liner 20 within a hydraulic cylinder 30 mounted on module 10 and liner retainer flange 22. Those of skill in the art will understand that a pump piston (not shown) attached to the power end of the pump is reciprocated within the liner 20 to effect the desired pumping action to flow fluid through the fluid end module 10 of the pump. Hydraulic cylinder 30 provides an open end into which the liner 20 is inserted. Module 10 also provides a counterbore 12 for the adjacent wear plate 14 against which it is desired to retain the liner 20 during operation of the pump piston. It can be appreciated that the purpose of wear plate 14 is to avoid the end of liner 20 wearing module 10 due to the reciprocation of the piston within liner 20. However, wear plate 14 may cause wear to the module 10 if the liner 20 is not securely affixed. Wear plate 14 may be replaced should that wear become excessive. It is noted that the end of the liner 20 adjacent the wear plate 14 includes an internal annular groove 59 with seal member 61 for sealingly engaging the wear plate 14 and the other open end 15 of liner 20 includes an external annular load-bearing shoulder 60 which retains end cap 64 (FIG. 2).
Part PAR_3: The hydraulic cylinder 30 includes a threaded, reduced diameter portion 24 and an enlarged diameter portion 32. Reduced diameter portion 24 is secured in a threaded or splined relation at 23 to liner retainer flange 22 that is located in an abutting relation to the module 10. Bolted studs 26 secure the cradle 28 of the pump power end, the liner retaining flange 22 and hydraulic cylinder 30 to module 10.
Part PAR_4: The enlarged portion 32 of hydraulic cylinder 30 includes an inner clearance cavity 33 which has a reduced diameter neck, forming a hydraulic cavity 58 to activate hydraulic piston 42 which in turn compresses springs 56 which are restrained from escaping from the spring cavity 35 by retainer ring 48. Hydraulic sealing is accomplished by sealing rings 39 and 49. End cap 64 is held in place with external threads 46. A hydraulic fluid port and fitting 38 is disposed through the wall of enlarged diameter portion 32.
Part PAR_5: When these components are assembled, the annular flange 44 of piston 42 forms hydraulic cavity 58 and outer spring cavity 35. The hydraulic fluid port and fitting 38 communicates with hydraulic cavity 58 for applying hydraulic pressure to flange 44. The spring cavity 35 houses a plurality of axially compressible Belleville springs or washers 56. Retainer ring 48 has external threads 50 which threadingly mate in a complimentary fashion with the internal threads 34 of enlarged diameter portion 32. The washers 56 bear against the retainer ring 48 and annular flange 44. Enough springs are used so as to insure sufficient force is generated to prevent movement of liner 20 when pump pressure rodriguezconnie@example.com. The retainer ring 48 secures the washers 56 and hydraulic piston 42 within the enlarged diameter portion 32 of hydraulic cylinder 30. O-ring 49 provides a fluid-tight seal between the piston 42 and enlarged diameter portion 32.
Part PAR_6: Upon assembly as shown in FIG. 1, hydraulic piston 42 has previously been inserted into enlarged diameter portion 32 of cylinder 30 to form cavities 58 and 35. Belleville washers 56 are inserted into outer spring cavity 35 and retainer ring 48 is threaded into place. The liner 20 is inserted into the outer hydraulic cylinder 30 of liner retaining assembly 18 so that the end of the liner 20 with seal 61 abuts wear plate 14.
Part PAR_7: Referring particularly to FIG. 2, the retaining assembly 18 is shown ready to secure the liner 20 in place. A hydraulic hose 62 is secured to the external port and fitting 38 for supplying hydraulic fluid to inner hydraulic cavity 58. As fluid pressure is supplied to cavity 58, fluid pressure is exerted against flange 44 urging piston 42 outward toward retainer ring 48. As annular flange 44 of piston 42 is so moved, springs 56 are axially compressed. As springs 56 are compressed, the threaded end 46 of piston 42 extends further away from wear plate 14 and module 10.
Part PAR_8: In the outward and extended position of piston 42, end cap 64 is threaded onto the threaded end 46 of the piston 42 so the threads 46 mate with the threads 66 of end cap 64. End cap 64 need only be hand tightened. It is noted that liner load bearing shoulder 60 mates with the shoulder 68 on end cap 64.
Part PAR_9: Referring now to FIG. 3, the retaining assembly 18 is shown completely assembled with the liner 20 securely affixed within the hydraulic cylinder 30. Once end cap 64 has been affixed, the fluid within the hydraulic cavity 58 is evacuated through port and fitting 38 permitting the springs 56 to bias flange 44 toward wear plate 14 and module 10 and bias end cap 64 against the other end 15 of liner 20. As the hydraulic pressure in the hydraulic cavity 58 is released, stored energy from the compression of springs 56 is released to load the liner 20 longitudinally. As a result, the energy stored by compressing springs 56 is transmitted to the liner 20 in order to load it longitudinally against wear plate 14 and module 10.
Part PAR_10: In order to remove the liner 20, the procedure is substantially reversed. Fluid is introduced into the hydraulic cavity 58 through port and fitting 38 in the same manner as previously described to compress springs 56 and external piston 42. Once spring forces are removed, end cap 64 may then be unthreaded. Fluid is bled off, springs 56 are decompressed and the unit is stabilized.
Part PAR_11: It is noted that the arrangement of the present invention permits a liner to be replaced rapidly and easily and without the use of extra tools or having to apply excessive torque. Further, a prestress force is applied to the liner 20 so that it is longitudinally compressed against wear plate 14 and module 10. This load or prestress securely holds the liner 20 against the wear plate 14 despite repeated reciprocation of the pump piston within liner 20.
Part PAR_12: Referring now to FIGS. 4 and 5, an alternative embodiment for an exemplary retaining assembly 70 is illustrated with the liner 20 inserted and securely affixed therewithin. For simplicity, like reference numerals are used for like or similar components. FIG. 5 is a cross-sectional view of the hydraulic cylinder 36 taken along plane V--V in FIG. 4.
Part PAR_13: In this embodiment, hydraulic cylinder 36 defines a plurality of individual piston chambers 72. There are 4, 6, or 8 chambers 72 (depending on the holding force required) which are azimuthally spaced around hydraulic cylinder 36. Each piston chamber 72 contains a wear cylinder sleeve 101 with an individual piston 74 that is reciprocably disposed therein. Wear sleeve 101 includes threaded bores 103 for receiving bolts to assist in the replacement of sleeves 101 when excessive wear has occurred. Each piston 74 provides an elongated shaft 76 and a radially extending flange 78 so that when disposed within the chamber 72, the chamber 72 is divided into a spring retaining chamber 80 and fluid chamber 82. The shaft 76 of the piston 74 is threaded at 84 for threadingly receiving a nut 86. Fluid may be introduced into the fluid chamber 82 through an associated hydraulic fluid port and external fitting 38.
Part PAR_14: A cover 88 is placed over the open end 15 of liner 20, the cover 88 having a central opening 90 through which liner 20 is disposed. The cover 88 also includes apertures 92 for the disposal of each piston shaft 76. The cover 88 serves to provide a solid surface against which Belleville springs 94 may be compressed. O-ring seals 96 surround the flange 78 of each piston 74 to ensure fluid sealing.
Part PAR_15: An end cap 98 is shown disposed over the cover 88. The end cap 98, like the cover 88, provides apertures 100 for receiving piston shafts 76. However, the central aperture 102 is only large enough to permit a portion of the liner 20 to be disposed therethrough, creating a shoulder 104 which mates with the shoulder 60 of liner 20.
Part PAR_16: Referring particularly to FIG. 5, a plurality of fluid passages 106 are provided in hydraulic cylinder 36 which interconnect and communicate with each piston chamber 72 and each of the ports and fittings 38 on the hydraulic cylinder 36. The fluid interconnection permits all of the fluid chambers 82 (FIG. 4) to be filled with fluid by using only one or a few of the hydraulic fluid ports and fittings 38 for injecting fluid. The common communication with all fluid chambers 82 also allows the common hydraulic actuation of all the pistons 74 (FIG. 4).
Part PAR_17: In operation as shown in FIG. 4, the liner 20 is installed and removed in a manner similar to that described with respect to liner retaining assembly 18. Fluid is introduced into each individual fluid chamber 82 urging the associated piston 74 to move toward the open end 15 of liner 20. Energy is stored through axial compression of the Belleville springs 94. The end cap 98 is placed onto the liner open end 15 so that the shoulder 104 engages shoulder 60 of liner 20. Nuts 86 are then tightened onto each piston 74. Again, the nuts need only be hand tightened. Fluid is then evacuated from the fluid chambers 82 and the Belleville springs 94 bias pistons 74 toward the wear plate 14 and the module 10, thus loading liner 20 longitudinally against wear plate 14 and module 10.
Part PAR_18: While preferred embodiments of this invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the system and apparatus are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.


{'bibliographic_information': "{'Patent Number': '062094459', 'Series Code': '9', 'Application Number': '1467867', 'Application Type': '1', 'Art unit': '375', 'Application Filing Date': '19980903', 'Title of Invention': 'Liner retainer assembly', 'Issue Date': '20010403', 'Number of Claims': '13', 'Exemplary Claim Number(s)': '1', 'Assistant Examiner': 'Lazo; Thomas E.', 'Primary Examiner': 'Look; Edward K.', 'Number of Drawing Sheets': '5', 'Number of figures': '5'}", 'source_file': './grant/2001/pftaps20010403_wk14.txt', 'source_data': 'USPTO-Grant'}