US3407746A

US3407746A - High pressure piston pump

Info

Publication number: US3407746A
Application number: US573678A
Authority: US
Inventors: Russell L Johnson
Original assignee: Individual
Current assignee: John E Mitchell Co
Priority date: 1966-08-19
Filing date: 1966-08-19
Publication date: 1968-10-29
Anticipated expiration: 1985-10-29

Description

Oct. 29, 1968 R. L. JOHNSON 3,407,746

HIGH PRESSURE PISTON PUMP Filed Aug. 19, 1966 2 Sheets-sheaf; .2

/37 743 INVENTQR:

RUSSELL. L-JOHNSQNI United States Patent 3,407,746 HIGH PRESSURE PISTON PUMl Russell L. Johnson, Dallas, Tex., assignor to The John E. Mitchell Company, Dallas, Tex., a corporation of Missouri Filed Aug. 19, 1966, Ser. No. 573,678 7 Claims. (Cl. 103-185) ABSTRACT OF THE DISCLOSURE A high speed multiple piston pump having an eccentric and follower for reciprocating a plurality of pistons and having bearings and movable parts that are self-lubricating. The constructing eliminates the requirement of seals to block off the bearing chambers from contact with the liquid flowing through the pump.

Brief description of the invention in general, the pump comprises a housing with a plurality of reciprocating pistons. A rotatable shaft carries an eccentric surrounded by a follower block. As the follower block oscillates upon rotation of the shaft and eccentric, wear surfaces carried by the follower block bear against the ends of the pistons, causing them to reciprocate. Ball valves in the pistons are opened and closed as the pistons reciprocate and they cooperate with ball valves near the outlet of the pump to cause fluid to be pumped.

The shaft which carries the eccentric is mounted in bearings, and all bearings and working parts have surfaces of graphite composition bearing against surfaces of stainless steel for long wear and self-lubrication, except that the piston members are slidable within brass cylinder liners and are molded of a self-lubricating and resilient plastic to provide slidability as well as expandability for sealing purposes.

A. principal object of this invention is to provide a high speed continuous operating pump having self-lubricating wear surfaces and bearings which need not be sealed against contact with liquid flowing through the pump, and the bearing characteristics of which are enhanced by the flow of liquid past them. Another object is to provide an uncomplicated, economically formed and assembled valve arrangement for assuring positive pumping action of a plurality of pistons within the pump.

Another object of the invention is to provide a liquid pump having reciprocating pistons formed of self-lubricating resilient plastic and having outlet valve assemblies downstream of the pistons wherein the pistons and the bodies of the outlet valve asemblies may be formed of common plastic in the same mold. A further object is to provide the piston and valve bodies of material which results in self-lubricating slidability of the pistons within cylinder liners while permitting expansion of they pistons within cylinder liners while permitting expansion of the piston sides against the cylinder liners for proper sealing, each piston and valve body also providing a housing for a ball valve and a good seat against which the ball member of the ball valve can operate.

This pump may be used for pumping any liquids for any purposes, but a typical use is in coin-operated car wash machines in which the pump may be subjected to hard service continuously day and night with little or no opportunity for servicing. Such pumps must operate against pressures of up to 550 pounds per square inch, normally causing considerable wear and tear on working parts and causing deterioration of bearings and burning out. A particular object of this invention is to provide a pump that can operate for long periods of time without lubrication or other servicing, that does not have seals to isolate the pumping chamber from the liquid but, to the ice contrary, has the liquid flowing past the working parts to keep them cool. Other objects are to provide such a pump that is inexpensive, easy to construct, and easy to assemble.

In the drawings:

FIGURE 1 is a top plan view of the pump;

FIGURE 2 is a side elevation view of the pump;

FIGURE 3 is an enlarged view in section taken along the line 3-3 of FIGURE 1;

FIGURE 4 is a view in section taken along the line 4-4 of FIGURE 3;

FIGURE 5 is a view in section taken along the line 5-5 of FIGURE 3;

FIGURE 6 is a view in section taken along the line 66 of FIGURE 3;

FIGURE 7 is a slightly enlarged fragmentary View in section taken along the line 7-7 of FIGURE 3;

FIGURE 8 is a slightly enlarged fragmentary view in section taken along the line 8-8 of FIGURE 3;

FIGURE 9 is a view in longitudinal medial section through a discharge valve body; and

FIGURE 10 is a view in longitudinal medial section through a piston with the wear pad installed.

The pump 20 has a housing 21 the main part of which comprises a cast iron block 22 having a front surface23, a back surface 24, a top surface 25, a bottom surface 26, and

side surfaces

27 and 28. A main bearing chamber 30 is cut through the block 22 from the front surface 23 to the back surface 24. The main bearing chamber 30 has

side walls

31 and 32, a top wall 33, and. a bottom wall 34.

Inlet chambers

35 and 36, which may be rectangular or circular in cross section, but of less diameter than the thickness of the block 22 between the front and

rear surfaces

23 and 24, extend from the main bearing chamber 30 toward the

opposite side surfaces

27 and 28 of the block. Front and

rear cover castings

38 and 39 are fastened by a plurality of bolts 40 to the front and

back surfaces

23 and 24 of the block 22 and cover the open ends of the main bearing chamber 30.

The

cover castings

38 and 39 are formed with

hearing wells

42 and 43, and an opening 44 extends through the front wall of the front cover casting 38.

Main bearings

45 and 46 are seated in the

bearing wells

42 and 43. The

main bearings

45 and 46 are cylindrical and are constructed of a graphite composition.

A main drive shaft 48 has

ends

49 and 50 journaled in the

bearings

45 and 46. Between the

ends

49 and 50 and the

bearings

45 and 46, the main drive shaft 48 is formed with an eccentric 51. An extension 52 of the shaft 48 projects through the opening 44 in the front cover casting 38 and has a keyway 53 for connection to a driving motor (not shown). An O-ring 54 provides a watertight seal between the shaft 48 and the front cover casting 38. The entire main drive shaft 48, including the eccentric 51, is made from a bearing grade stainless steel.

A cylindrical bearing 57 of graphite composition is mounted within the opening 58 in the center of a follower block 59. The bearing 57 surrounds the eccentric 51, but the eccentric 51 can rotate relative to the bearing 57. The follower block 59 has upper and

lower arms

60 and 61 extending above and below the area of the eccentric 51. Disk-shaped recesses 62 and 63 are cut in opposite sides of the upper arm 60 and disk-

shaped recesses

64 and 65 are cut in the opposite sides of the lower arm 61. Wear pads 66, 67, 68 and 69, each of graphite composition, are mounted in the

recesses

62, 63, 64 and 65, respectively. There is a small passage 70 drilled between the wear pad recesses 62 and 63 and a small passage 71 drilled through the end of the arm 60 to the passage 70. Similarly, there is a small passage 72 drilled between the

wear pad recesses

64 and 65 and a small passage 73 drilled through the end of the arm 61 to the passage 72.

Four

holes

75, 76, 77 and 78 extend through the sides 3 of the casting 21, the holes and 77 extending from the side 27 through to the main bearing chamber 31 and the holes 76 and 78 extending from the side 28 through to the main bearing chamber 31. The holes 75, 76, 7'7, and 78 may be drilled or formed during the casting of the block 21.

Recesses

80 and 81 are cast or drilled from the

opposite sides

27 and 28 of the block 22 with a passage 82 of smaller diameter extending between the

recesses

80 and 81. Where the passage 82 joins the

recesses

80 and 81, shoulders 83 and 84 are formed.

Two

side castings

86 and 87 are fastened to the

sides

27 and 28 of the block 22 by a plurality of bolts 88. There is a vertical passage 89 through the side casting 86 with

side openings

90 and 91 communicating with the

holes

75 and 77 in the block 22. The

openings

90 and 91 are countersunk to provide

spring seats

92 and 93. Another side opening 94 extends through the side casting 86 and communicates with the recess 80. Upper and lower threaded plugs 95 and 96 block the ends of the liquid passage 89.

Another vertical liquid passage 97 extends through the other side casting 87. Side openings 98 and 99 communicate with the holes 76 and 78 in the block 22, and the openings 98 and 99 are countersunk to provide

spring seats

100 and 101.

An opening 102 through the side of the side casting 87 communicates with the recess 81.

Plugs

103 and 104 are threaded into the side casting 87 to block the upper and lower ends of the passage 97. The

plugs

103 and 104 and the plugs 95 and 96 permit access to the

passages

97 and 89 for cleaning purposes.

There are two

inlet ports

105 and 106 opening into the

inlet chambers

35 and 36, respectively. The

inlet ports

105 and 106 are adapted to be connected to different sources of liquid supply via

pipes

107 and 108. For example, the inlet port 105 may be connected to a water source and the inlet port 106 to a detergent or concentrate source. An outlet port 109 leads from the passage 82 and is internally threaded to receive the end of a pipe or hose which may be connected to an outlet nozzle (not shown).

A cylinder liner 110 is mounted in the hole 75 with an O-ring 111 to provide a Watertight seal between the cylinder liner and the cylinder head. A similar cylinder liner 1'12 and O-ring 113 are mounted in the hole 76, a cylinder liner 114 and O-ring 115 in the hole 77, and a cylinder liner 116 and O-ring 117 in the hole 78. The

cylinder liners

110, 112, 114 and 116 are formed of standard brass jump liner stock. Separate piston and

valve assemblies

118, 119, 120 and 121 are mounted in the

cylinder liners

110, 112, 114 and 116. The piston and

valve assemblies

118, 119, 120 and 121 include

pistons

122, 123, 124 and 125 which are slidable within the

cylinder liners

110, 112, 114 and 116. Since the piston and

valve assemblies

118, 119, 120 and 121 are identical in construction, only the assembly 119 is shown in detail in FIGURE 3.

As shown in FIGURE 3, and more particularly in FIG- URE 10, the piston 123 has a cylindrical outer surface between opposite ends 131 and 132. A passage 133 leads from the end 131 to a larger diameter recess 134. An annular notch is formed within the piston 126 adjacent the recess 134 to provide an annular groove 135 and beyond the groove 135, an inner wall 136 is tapered outwardly toward the end 132. There are a plurality of liquid ports 137 opening from the side wall 130 and leading to the passage 133. A short section 138 adjacent the end 131 of the piston is formed to a reduced diameter, and beyond the section 138 there is an annular notch 139. A cap 140 of bearing grade stainless steel fits over the end 131 and the short section 138 of the piston 126 and has an inturned flange 141 which snaps into the annular notch 139. There are shallow annular grooves in the outer surface 130 of the piston 126 for receiving piston rings 142. The pistons 122-125 are injection molded or otherwise formed of Delrin-AF or similar plastic material.

4 Each

piston

122, 123, 124 and 125 has a valve assembly in it, as illustrated for the piston 123 in FIGURES 3 and 8. Each valve assembly includes a spring seat 146 snapped into the annular groove 135 upon passing it through the entrance defined by the tapered wall 136. The spring seat 146 has a passage 147 through its center with a well 148 on one side and an annular wall 149 on the other side. A light spring 150 is seated in the well 148 and bears against the side of a ball 151, urging the ball 151 into seating engagement with the mouth of the passage 133 in the piston. Another spring 152 is seated against the annular wall 145 and against the countersunk spring seat 100 and biases the piston member 123 (and the piston member 125) to the left as viewed in FIGURE 3, (to the right for the piston members 122 and 124), to maintain contact between the wear pad 67 and the cap 140 mounted on the end of the piston member 123.

A pair of

outlet valve assemblies

155 and 156 are mounted in the

recesses

30 and 81. The

outlet valve assemblies

155 and 156 are identical, and only the assembly 156 is shown in detail in FIGURE 3. This outlet valve assembly comprises a piston member 157 which is identical to the piston member 123 shown in FIGURE 10, as the application of identical reference characters indicates. The piston members are molded of Delrin-AF plastic material and are interchangeable with the pistons 122-125.

A spring retainer 158, which is identical to the spring retainer 146, is snapped into the groove 135 of each piston member 157. The spring retainer 158 has a passage 159 through its center and a well on one side. A light spring 161 is seated in the well and bears against a side of a ball member 162 to bias the ball member 162 against the mouth of the passage 133 through the piston member 157.

Operation Water and concentrate enter through the

inlet ports

105 and 106, any suitable means being used to regulate the proportions of water and concentrate. The Water and concentrate flow from the

inlet chambers

35 and 36 into the pumping chamber 30 where they are mixed. Depending upon the open or closed positions of the various valves, the water and concentrate liquid mixture flows through each of the piston members 125, 126, 127 and 128, entering through the ports 137 and flowing through the passage 133, the recess 134, the opening 147 in the spring seat 146, and the passage 136 to the

openings

90, 91, 98 and 99 and through the

vertical passages

89 and 97. The liquid mixture flows through the

openings

94 and 102 into the

piston members

155 and 156, flowing through the passages 133, the recesses 134, the openings 159 in the spring seats 158, and the passages 136 to the passage 82 and out the outlet port 106.

The aforesaid flow of liquid is caused by the operation of the piston and

valve assemblies

118, 119, 120 and 121. Operation of the piston and valve assemblies is effected by rotation of the shaft 50 and the eccentric 51, causing the follower block 59 to oscillate. As the follower block 59 oscillates, its upper and

lower arms

60 and 61 move in unison alternately to the left and right (as well as vertically) as viewed in FIGURE 3. On movement of the follower block 59 to the right to the position shown in FIGURE 3, the wear pads 67 and 69 bear against the caps 140 on the piston members 123 and 125, moving the piston members to the right or outwardly against the forces of the springs 152. At the same time, the springs 152 cause the

piston members

122 and 124 to move to the right or inwardly as their caps 140 maintain contact with the wear pads 66 and 68. Further rotation of the shaft 50 and eccentric 51 produces the opposite operation with the

piston members

122 and 124 being driven to the left or outwardly and the piston members 123 and 125 move to the left or inwardly.

When the piston member 123 moves to the left or inwardly as viewed in FIGURE 3, liquid pressure in the passage area between the ball member 151 and the ball member 162 in the outlet valve assembly 157 is reduced because the light spring 161 and the pressure against which the pump operates holds the ball member 162 seated against the mount of the passage 133. Liquid from the pumping chamber 31, supplied through the

inlet ports

105 and 106, forces the ball member 151 away from the mouth of the passage 133 as the liquid flows through the ports 137 (see FIGURE When the piston member 123 nears the end of its inward stroke, the liquid has flown past the ball member 151 and raised the liquid pressure downstream of the ball member 151, the light spring 150 again seats the ball member 151 against the mouth of the passage 133. Then, when the piston member 123 is driven to the right or outwardly as viewed in FIGURE 3, the liquid pressure downstream of the ball member 151 keeps the ball member 151 seated against the mouth of the passage 133 and pushes the ball member 162 away from the mouth of the passage 133 in the valve body 157. The outward movement of the piston member .123 therefore forces liquid past the ball member 162 and through the outlet port 106.

The operation of the other

piston valve assemblies

118, 120, and 121 is similar to the foregoing description of operation of the piston and valve assembly 119, and the operation of the outlet valve assembly 155 is similar to that of the outlet valve assembly 156. The piston and valve assemblies 119 and 121 generally operate in unison and control the operation of the outlet valve assembly 156, and the piston and

valve assemblies

118 and 120 operate in unison and control the operation of the outlet valve assembly 155.

The design of this pump and the use of materials for various parts of the pump have given results far superior to those of conventional pumps. This is a high speed pump designed to operate at up to 1200 rpm. in continuous operation and without servicing.

This pump and conventional pumps operate against pressures up to 550 pounds. Conventional pumps have bearings requiring frequent lubrication and break down from the entrance of small particles of dirt into the bearings. Pumps requiring grease often fail from lack of grease servicing, particularly where constant use prevents opportunities for access by a servicemen. Other pumps isolate the bearing area so that liquid cannot enter the bearing chamber. These isolations are done with seals, but the seals tbreak down and cause pump failures.

In this pump, the bearings and movable parts are selflubricating and their lubrication is even improved when water or water and detergent pass through the working parts. In this pump then, water and detergent are purposely admitted to the pumping chamber and the bearing chambers whence they are pumped through the piston and valve assemblies for discharge. The bearing grade stainless steel of the shaft 50 and eccentric 51 works with the graphite composition of the bearing 57 to provide selflubrication and long life. The same is true for the

bearings

45 and 46 operating in contact with the stainless steel shaft ends 49 and 50. The wear pads 66, 67, 6S and 69 of graphite composition are self-lubricating as they slide against the stainless steel caps 140 on the piston members .122, 123, 124 and 125.

Ther piston members

122, 123, 124 and 125 are easily slidable within the

piston liners

110, 112, 114 and 116, the latter being made of standard brass pump liner stock, and the piston members being molded of Delrin-A.F. This piston material provides good resistance to wear and corrosion while giving suificient resilience to permit the retainer rings 150 and 158 to be snapped into place in the grooves 135. Also, the resilience of the

piston members

122, 123, 124 and 125 enables the piston members to expand under operating pressures to form tight seals against the cylinder liners while the self-lubrication permits the piston members to slide. Still, further, the resilient material of the piston members provides a good seat for the

ball members

151 and 162 against the mouths of the passages 133.

Various changes and modifications may be made within the purview of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teachings of this invention as defined by the claims appended hereto.

What is claimed is:

1. A liquid pump comprising a housing, a main bearing chamber within the housing, an inlet to the housing in communication with the main bearing chamber, an outlet from the housing in communication with the main bearing chamber, a drive shaft, drive shaft bearings supported in the housing, the drive shaft being rotatably journaled within the drive shaft bearings, an eccentric carried by and rotatable with the drive shaft, a follower block surrounding the eccentric for oscillation of the follower block when the eccentric is rotated with the drive shaft, a plurality of piston chambers in the path of communication between the main bearing chamber and the outlet port, a piston member reciprocable within each piston chamber, a working surface on the follower block corresponding to and in contact with an end of each piston member, means for maintaining contact between the working surfaces and the piston members, valve means for causing liquid to flow from the inlet to the outlet when the pistons reciprocate, the contact surfaces between the drive shaft and the drive shaft bearings, between the eccentric and the follower block, and between the working surfaces on the follower block and the ends of the pistons in contact with the working surfaces being of self-lubricating bearing materials and being exposed to contact with liquid flowing through the pump housing, the working surfaces being defined by wear pads of graphite composition carried by the eccentric and the ends of the pistons in contact with the working surfaces being of stainless steel construction.

2. The liquid pump of claim 1 wherein the piston member is molded of self-lubricating plastic, and a cylinder liner of brass construction in the piston chamber, the piston member being slidable within the cylinder liner.

3. The liquid pump of claim 1 wherein the piston member has a liquid passage through it, the valve means comprising a ball member within the piston member, means biasing the ball member toward seating engagement with the passage to block the flow of liquid through the passage in opposition to inlet pressure tending to unseat the ball member, and check valve means in the liquid passage between the piston member and the outlet to prevent flow of liquid from the outlet toward the piston member.

4. The liquid pump of claim 3 wherein the check valve means comprises a valve body identical to the piston member with a liquid passage through it, a ball member within the valve body and means biasing the ball member toward seating engagement with the liquid passage in the valve body to block the flow of liquid through the passage in opposition to flow of liquid from the piston member toward the outlet tending to unseat the ball member in the valve body.

5. A liquid pump comprising a housing, a main hearing chamber within the housing, shaft bearings supported in the housing on opposite sides of the main bearing chamber, a shaft having ends journaled in the shaft bearings and having an eccentric between the shaft ends and positioned in the main bearing chamber, the shaft and eccentric being of bearing grade stainless steel, a follower block having a central opening, a sleeve of graphite composition adhered to the opening in the follower block and rotatably surrounding the eccentric, the follower block having a pair of diametrically opposing arms, each arm having a first side facing in a first direction and a diametrically opposite second side facing in a second direction, wear pads of graphite composition mounted! in the first and second sides of the arms, a pair of first piston chambers in the housing opposite the first sides of the arms, a pair of second piston chambers in the housing opposite the second sides of the arms, a piston member reciprocable Within each piston chamber, a bearing grade stainless steel cap fixed to an end of each piston member for contacting the adjacent wear pad mounted in the follower block, means biasing the pistons toward the follower block to maintain sliding contact between the caps and the Wear pads, whereby oscillation of the follower block upon rotation of the shaft and eccentric causes the pistons to reciprocate, an inlet passage through the housing in communication with the main bearing chamber, an outlet passage through the housing, first and second liquid passages through the housing, the first liquid passage leading from the main bearing chamber through the piston members in the first chambers to the outlet passage, the second liquid passage leading from the main bearing chamber through the piston members in the second chambers to the outlet passage, and valve means in each liquid passage to permit liquid to be driven by the reciprocation of the pistons from the main bearing chamber to the outlet pas- 20 sage while preventing reverse flow of the liquid.

3 6. The liquid pump of claim 5 wherein the piston members are of self-lubricating plastic and the piston chambers are lined with brass sleeves.

7. The liquid pump of claim 5 wherein the housing is 5 cast iron.

References Cited UNITED STATES PATENTS 2,595,738 5/1952 Walker 230206 X 2,603,158 7/1952 Nemetz 103169 2,696,413 12/1954 Wheildon 230-206 X 2,888,879 6/1959 Gaarder 92-155 3,037,830 6/1962 Junod 92169 3,070,030 12/1962 Mashinter 103150 3,134,305 5/1964 Jensen 92169 3,212,411 10/1965 Storms 92-155 FOREIGN PATENTS 531,191 1/1922 France.

WILLIAM L. FREEH, Primary Examiner.