US2851957A - Diaphragm pump - Google Patents

Description

Sept. 16, 1958 D. RAGLAND DIAPHRAGM PUMP Filed Dec. 19, 1955 2 v. w V/ 7 g a I Doug/as Rag/and,

' ATTORA/EX United States Patent 2,851,957 DIAPHRAGM PUMP Douglas Ragland, Houston, Tex., assignor, by mesne assrgnments, to Jersey Production Research Company Application December 19, 1955, Serial No. 553,888 1 Claim. (Cl. 103-150) This invention is directed to a device for transmitting fluid pressure. More specifically it is directed to a device for pumping high pressure abrasive liquids such as drilling muds, and the like.

The life of pistons, rods, liners and rod packing in reciprocating slush pumps used in Welldrilling operations, is relatively short because of the abrasive, erosive and corrosive materials acting upon the moving parts of the P p- A diaphragm pump, on the other hand, substitutes a diaphragm and a fluid piston system for the mechanically operated piston of the reciprocating type pump thereby eliminating contact between the piston and the liquids being pumped. However, the use of a fluid piston in practice limits diaphragm-type pumps to low pressure operation as it is diflficult to obtain and control high fluid piston pressures necessary to actuate the diaphragm, because of fluid leakage inherent in fluid pump systems. It is also diificult to prevent rupture or other damage to present pump diaphragms since they are not designed for high pressure operation. One object of this invention, therefore, is to provide a high pressure type slush pump wherein the life of the pump elements is substantially lengthened.

Briefly, the invention comprises a pump casing provided with inlet and outlet fluid passages, the passages being provided with valve means whereby the inlet and dis charge of fluid through the pump casing is controlled. A piston rod is arranged to reciprocate in the pump casing and a high pressure diaphragm is connected between the pump casing and the piston rod. The advantages of this device reside in maintaining the abrasive liquids being pumped out of contact with the reciprocating piston arm and at the same time utilizing the desirable features of mechanically actuated pistons and high pressure diaphragms. The abrasive liquids herein contact only the diaphragm.

The invention will be more fully described with refer ence to the drawing wherein the sole figure is a sectional view of the device.

Referring more particularly to the drawing, wherein identical numerals designate identical parts, numeral 10 designates a pump casing enclosing a pump chamber 9. Valve pots 11 and 12 are arranged on each side of the pump casing. The center portion of one side of the pump casing forms a cylindrical sleeve 13. A piston rod 14, provided with an enlarged head portion 15, is arranged for reciprocating movement in the pump casing 10. Piston rod head 15 is spaced from sleeve 13, as shown, and is of smaller diameter than the annular sleeve. For example, the sleeve 13 may be 7 /2 inches in diameter and the rod head 15, /2 inches in diameter. Other dimensions for the sleeve and the rod head may be used provided a ratio about or approximating that for the specific example given is used. Such ratios provide the required clearance for operation. The outer periphery 17 of an annular high pressure diaphragm 16 which is provided with a central portion U-shaped in cross-section is connected into a recessed portion 18 of the lower wall 19 of the pump casing. This outer end 17 may be secured by means of an annular plate member 20 and bolts 21. The inner periphery 22 of the annular high pressure diaphragm 16 may be secured to the enlarged head portion 15 of piston rod 14 by means of a plate member 23 and a bolt 24. The diaphragm is preferably made in accordance with the disclosure in U. S. Patent No. 2,678,065, issued to Robert R. Crookston, May 11, 1954, in which a deformable circular U-shaped base member has molded thereon at least a layer of overlapping woven fiber ribbons. This diaphragm is designed to provide long life at high pressure operations. High pressure as defined herein means pressures of 3500 pounds per square inch or greater. The preferred operating pressure range is 3500 to 5400 pounds per square inch although the diaphragm will operate efliciently with pressures as low as 200 pounds per square inch.

A removable valve chamber plug 25 is positioned on the opposite side of the pump casing 10 from sleeve 13 and is secured to the pump casing 10 by means of bolts 26. The inlet valve pot 12 is provided with a valve seat 30 upon which a valve member 31 is adapted to seat. A removable valve pot plug 32 is arranged on the pump casing 10 and is secured thereto by means of bolts 33. The plug 32 is provided with a recessed portion 34 into which extends a connecting rod 35 attached to valve member 31. Suitable biasing means such as spring 36 engages with the surface of valve member 31 and plug 32 and is adapted to normally bias the valve member 31 against the seat 30. Similarly, the discharge valve pot 11 is provided with a plug member 40 secured to the pump casing 10 by means of bolts 41 and is provided with a recessed portion 42 into which extends a rod 44 attached to valve member 46. Biasing means such as spring 45 biases valve member 46 against valve seat 47 formed in valve pot 11.

In operation, reciprocation of piston rod 14 by means of any desirable type prime mover, not shown, mechanically connected thereto, opens and closes the inlet and discharge valves 30 and 46 to provide the pumping action for the pump device. For example, as shown by the lower dotted lines in Fig. 1 designating the intake position of piston rod 14, valve 30 opens, as shown in dotted lines, and valve 46 closes under the bias of spring 45. Upon upward movement, shown by the upper dotted lines in the drawing designating the exhaust position of piston rod 14, valve 31 seats on valve seat 30 and valve element 46 moves upwardly against the bias of spring 45 as shown in dotted lines, thereby exhausting the high pressure fluid contained in the pump chamber 9 of the pump casing 10.

Having fully described the elements, objects and operation of my device I claim as my invention:

A fluid pump comprising a housing formed to provide a chamber therein, said chamber being provided with a fluid inlet and a fluid outlet, valve means arranged in said inlet and said outlet for controlling the flow of fluid through said chamber, said housing having a cylindrical sleeve member formed thereon, a reciprocable cylindrical rod member spaced from and arranged interiorly of said sleeve member, a reinforced high pressure diaphragm having a'portion U-shaped in cross-section connected at its outer periphery to said housing and at its inner periphery to said rod member, said U-shaped portion of said diaphragm being positioned between said sleeve member and said rod member, said diaphragm being arranged such that said U-shaped portion thereof is retained in the space between said sleeve member and said rod member during reciprocation of said rod member, portions of said diaphragm other than said U-shaped portion being supported by said sleeve member and said rod member.

References Cited in the file of this patent UNITED STATES PATENTS 109,678 Shearer Nov. 29, 1870 1,570,861 Quiroz Jan. 26, 1926 1,659,860 Denholrn Feb. 21, 1928 2,414,806 Finney Jan. 28, 1947 FOREIGN PATENTS 823,180 Germany Dec. 3, 1951

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