US3476057A - Aggregate pumping apparatus - Google Patents

Description

Nov. 4, 1969 Filed Sept. 8, 196'? P. W. MCELROY AGGREGATE PUMPING APPARATUS 2 Sheets-Sheet 1 F|G.I

52 HYDRAULIC PRESSURE SYSTEM l2 L' "g Y l 2 J INVENTOR.

Y PHILIP VLMC ELROY Nov. 4, 1969 P, w. MGELROY AGGREGATE PUMPING APPARATUS 2 Sheets-Sheet 2 INVENTOR.

PHILIP W. MC ELROY www ATTORNEYS United States Patent O 3,476,057 AGGREGATE PUMPING APPARATUS Philip W. McElroy, 2300 Dolores Court, Pinole, Calif. 94564 Filed Sept. 8, 1967, Ser. No. 666,442 Int. Cl. F04b .Z9/04, 1/00; F15b 11/20 U.S. Cl. 103--167 4 Claims ABSTRACT F THE DISCLOSURE This invention relates to apparatus for pumping dense aggregates such as concrete aggregate.

Because of the high abrasive character of concrete aggregate, pumps adapted for handling such aggregate must be of simple and rugged construction. A pump according to the present invention provides such construction.

The essential elements of a concrete pump according to the present invention are a concrete hopper having a discharge outlet at the bottom, a piston chamber that supports a piston therein for reciprocal movement to `draw aggregate into and expel aggregate from the chamber, and a valve controllably interconnecting the concrete hopper and the piston chamber so that in one phase of operation, concrete is transferred from the hopper into the piston chamber and in a second phase of operation, concrete is discharged from the piston chamber through an outlet in the valve.

An important object of the present invention is to provide a valve operable as described above that is of simple long-wearing construction and which requires only minimum power. Power required for operating the valve is minimized by providing a valve gate plate that is curved to dene a segment of a cylindric surface and by actuating the gate plate around the central axis of such cylindric surface so that the plate moves transversely of the direction of concrete ow. Such direction of gate plate movement requires a minimum amount of power because movement in such direction renders unnecessary overcoming the pressure of the concrete.

Further contributing to the simplicity of the present invention is a valve housing in which the above described gate plate is supported. The housing has three passages therein that extend radially of the cylindric axis. With the first of these openings is associated the piston chamber; with the second of these openings is associated the concrete hopper. The third opening is the concrete discharge opening. The gate plate is rotatably movable so as to close either the concrete hopper opening or the discharge opening. Thus, 'the piston chamber communi cates with the aggregate hopper during its loading stroke and with the discharge opening during its discharge stroke.

The present invention also includes in combination with the hopper piston chamber and valve described above, a second piston chamber that has a displacement volume equal to one-half the previously mentioned piston chamber. Such combination affords a continuous ow of concrete by operating to load the secondary piston chamber during the discharge stroke of the primary piston chamber and to discharge the secondary chamber into an outlet line while the primary chamber is being charged from the hopper. Thus, a steady discharge is achieved without complicated structures.

"ice

Another aspect of the invention resides in an improved hydraulic control system for controlling the valve and the primary and secondary pistons in proper timed relation.

The foregoing as well as other objects, features and advantages of the present invention will become more apparent after referring to the following specification and accompanying drawings in which:

FIG. 1 is a plan view of the apparatus of this invention, portions being broken away to reveal internal details thereof;

FIG. 2 is an elevation view taken along line 2 2 of FIG. l;

FIG. 3 is a transverse cross section in elevation taken along line 3-3, of FIG. 2;

FIG. 4 is a perspective view of the valve gate plate of the present invention; and

FIG. 5 is a partially schematic view of the hydraulic control system of the present invention.

Referring more particularly to the drawing, reference numeral 12 indicates a primary piston chamber mounted on a frame member 13. Piston chamber 12 supports a piston or plunger 14 which is reciprocally driven within the chamber in a charge stroke and a discharge stroke by a rod 16. Piston chamber 12 is attached to a valve housing `18, the valve defining a cylindric cavity 20 with which the interior of piston chamber 12 communicates through a port 22.

Also secured to valve body 18 is a concrete hopper fragmentarily indicated at 24 which communicates to cavity 20 through an opening 26. Valve body 18 finally includes a discharge port 28 which communicates to an outlet pipe tting 30.

Supported interior of valve casing 18 is a valve 'body assembly designated generally by reference numeral 34 in FIGURE 4. The assembly includes a curved gate plate 36 that forms a segment of a cylinder. The gate plate is mounted at its ends to two circular end members 38 and 40. Stub shafts 42 and 44 are respectively secured centrally of circular plates 38 and 40.

Valve housing 18 is bushed at 46 and 48 to respectively support for rotation stub shafts 42 and 44, so that gate plate 36 is concentric with the surface of cavity 20. The valve assembly 34 is movable between a position at which gate plate 36 closes port 26 (see FIG. 2) and a position at which the gate plate overlies outlet port 28 (indicated by broken lines in FIG. 2). A lever arm 50 is attached to shaft 42 to effect such movement of the gate plate, a hydraulic cylinder 52 having a rod 54 connected to lever arm 50 being provided to so drive the lever arm.

Outlet pipe fitting 30 defines one leg of a Y tting 56 which has an outlet pipe 58 and a branch 60. Branch 60 is attached to a secondary piston chamber 62 which is mounted on frame 13 generally parallel with primary chamber 12. Secondary piston chamber 62 supports interior thereof a piston or plunger 64 which is driven through a discharge stroke and a charging stroke by a piston rod 66. Secondary piston chamber 62 has a crosssectional area equal to one-half the cross-sectional area of piston chamber 12 so that when piston -64 moves an amount equal to the movement of piston 14 the displacement from chamber 62 is one-half that of chamber 12. In one pump designed according to the present invention a piston 12 having an inside diameter of 11% inches was used with a chamber 62 having an inside diameter of 8 inches.

The operation of my improved valve and pump can be understood by assuming that hopper 24 is full of concrete aggregate and that gate plate 36 is in the position shown by solid lines in FIG. 2. Piston 14 is at the beginning of the charging stroke in chamber 12, that is, the

piston is at its left extremity of movement as viewed in the figure. First, hydraulic cylinder 52 is energized to move gate plate 36 in a counter-clockwise direction to the broken line position as viewed in FIG. 2, simultaneously with which piston 14 is moved rightwardly by hydraulic systems to be described hereinbelow. Concrete aggregate enters cavity 20 by gravity and is drawn into chamber 12 as piston 14 moves rightwardly in its charging stroke. Simultaneously, with such movement, piston 64 moves in a discharge stroke within chamber 62 that is, piston 64 moves leftwardly as seen in FIG. 1. When piston 14 has completed its charging strokes so that chamber 12 is iilled with aggregate, hydraulic cylinder 52 is again actuated to move the valve assembly clockwise as viewed in FIG. 2 so that gate plate 36 closes port 26 and opens port 28. Such movement of the gate plate takes relatively little power since the gate is moving in a direction transverse to the direction of concrete ow. Also, minimizing the power necessary to close the gate is a bevel indicated at 67 in FIG. 2 that is formed on the edges of gate plate 36. Movement of the gate plate to a position closing port 26 inhibits further delivery of concrete from hopper 24. On leftward movement of piston 14 through a discharge stroke, aggregate is moved leftwardly as viewed in the figure through port 28 and into conduit 30. Because substantial resistance exists downstream of outlet pipe 58, some of the aggregate will flow into branch 60. Moreover, movement of piston 64 rightwardly in chamber 60 draws the aggregate into chamber 62. Because chamber 62 has a displacement equal to one-half that of chamber 12, one-half of the aggregate discharged from chamber 12 is conveyed out through pipe 58 and one-half is loaded into chamber 62. When pistons 14 and `64 return to the positions shown in FIG. 1, gate plate 36 again moves counterclockwise to close port 28. Piston 64 is then driven in a discharge stroke, leftwardly as viewed in the figure, so as to discharge the contents of cylinder 62 through outlet conduit 58. Also occuring at this time, as a consequence of rightward movement of piston 14, is charging of cylinder 12 with aggregate from hopper 24. Thus, chamber 12 is loaded for the next stroke, and the sequence of operations described continues in alternation to deliver a continuous ow of concrete through outlet l58.

For efliciently operating pistons 14 and `64, a hydraulic actuator 68 is connected in driving relation to rod 16 and a hydraulic actuator 70 is connected in driving relation to rod 66. The operation and control of these actuators is shown in more detail in FIG. 5.

A piston 72 is mounted for reciprocating movement within actuator 68; piston 72 is attached to rod 16 which extends into actuator 68. Correspondingly, a piston 74 is attached to rod 66 and is disposed in actuator chamber 70 for reciprocating movement therein. The left or rod ends of actuators 68 and 70 are connected to one another through a tube 76. To the opposite end of actuator chamber `68 is connected a fluid line 78 which, through a solenoid valve 80, is selectively connected to a source of hydraulic iiuid under pressure `82 and a return reservoir 84. On the opposite end of actuator chamber 70 a uid line 86 is connected to a solenoid valve 88 which is also selectively connectable to pressure source 82 and hydraulic fluid return reservoir `84. Valves 80 and 88 are operated in unison by an electro-magnetic solenoid coil 90. The coil 90 is connected to a battery 92 through a double pole, double throw reversing switch 94. The moving contacts of the switch are operatively associated with spaced apart discs 96 and 98 which discs are mounted on an actuator rod 100.

Actuator rod 100 is carried in a guide 102 in the end of actuator chamber 68. The inner end of rod 100 is supported in a central bore 104 of piston 72. Bore 104 has a reduced diameter portion 106 and rod 100` has an enlargement 108 which cooperate to move disc 96 leftwardly so as to effect reversal of switch 94 when piston 72 reaches its leftward extremity of travel. When piston 72 reaches the rightward extremity of its movement within actuator chamber 68, enlargement 110 on actuator rod 100 is engaged by piston 72 so as to move disc 98 into contact with the reversing switch 94. Rod 16 is hollow so as to permit rightward movement of piston 72 without interference with actuator rod 100.

The operation of this portion of the hydraulic system can be understood if it is assumed that pressurized hydraulic fluid is being delivered through valve and fluid line 78 into actuator chamber 68 so as to drive piston 72 leftwardly. AS the piston reaches its leftward extremity, a position that it has just reached in FIG. 5, the disc 96 will move the armature or moving arm of reversing switch 94 to the left and will energize coil 90 so as to actuate valves 80 and 88. When valves 80 and 88 are rotated in the direction of the respective arrows by about 45 degrees, valve 80 connects fluid line 78 to return reservoir 84, and valve 88 connects iiuid line 86 to pressurized iiuid source `82. The consequence of the latter actuation is that piston 74 will be moved to the left and piston 72 will 'be moved to the right until the latter piston encounters enlargment 110 and moves rod so that disc 98 reverses switch 94 again. Thus, it will be seen that pistons 14 and 64 will be reciprocated so as to discharge concrete aggregate as described herein above.

It has been found that evenk the highest quality hydraulic piston or actuator has a certain amount of leakage which, if unCOmpanSated, would soon permit the two pistons to operate out of the proper phase. To compensate for such leakage as may occur, piston 74 is provided with a valve assembly to assure proper cooperation of the pistons. Piston 74 is formed with a fluid passage 112 therethrough at the high pressure or right end of which is formed a chamfered seat that is normally closed by a valve 114. Valve 114 has a stern 116 that extends through passage 112; a compression spring 118 is mounted in circumscribing relation to the valve stem for normally biasing valve 114 to a closed position. a lever 119 pivotly mounted to rod 66 at 120 is attached at one end to valve stem 116 and at the other end to an actuator rod 122. Rod 122 extends through a bore in piston 74 and extends beyond the face of the piston as at 124.

The operation of the uid leakage compensation system is as follows:

If a piston 74 is driven rightwardly as viewed in FIG. 5 by uid forced through line 76 by leftward movement of piston 72 and such movement is excessive, actuator rod end 124 will contact the right end wall of actuator chamber 70 before reversing switch 94 is operated by disc 96. The consequence of such contact by rod end 124 is that lever 119 rocks to open valve 114 so as to permit uid to pass piston 74 without driving the piston. If pressurized fluid is now supplied to chamber 70 through valve 88 and line 86 (that is, on the right face of piston 74) and if leakage past piston 72 occurs, piston 74 can reach the leftward extremity of actuator chamber 70 before piston 72 urges disc 98 into contact with the reversing switch 94. If such happens, the left extremity of valve stem 116 contacts the left end wall of actuator chamber 70 and forces valve 114 open against the force of spring 118. This permits Huid to bypass piston 74 until piston 72 moves rightwardly by an amount suicient to effect reversal of switch 94. By a relatively uncomplex valve structure hydraulic fluid leakage is compensated to the end that pistons 72 and 74 are in proper phase relation at all times.

It will thus be seen that the present invention provides yan improved valve for concrete aggregates, an improved pump system for pumping concrete aggregates, and an improved electro-hydraulic control system for such pump. Because of the relatively few simple moving parts in the system, extremely long trouble-free operation can be achieved.

Although one embodiment of the invention has been shown and described, it Will be obvious that other adaptations -and modifications can be made without departing from the true spirit and scope of the invention.

I claim:

1. Apparatus for pumping concrete aggregate comprising first and second plunger chambers each having an outlet opening and iirst and second plungers slidably supported in said chambers for reciprocal movement towards respective said openings in a discharge stroke and away from respective said openings in a charge stroke, hydraulic actuators for actuating said plungers, each actuator comprising a cylinder, a piston axially movably disposed in the cylinder and rod means interconnecting a plunger and a piston, the apparatus further including iirst conduit means interconnecting end portions of the cylinders which are adjacent the position of the pistons at the end of the respective discharge strokes of the plungers, Iand valve means for maintaining the pistons in phase during the operation of the hydraulic actuators, the valve means being mounted to one of said pistons and comprising a closure member axially movably mounted in a passage defined by said one piston, means biasing said closure member in a passage closing position, and means moving said closure member in a passage opening position when said piston approaches the re spective cylinder ends, whereby a premature arrival of said one piston at one of said ends, relative to the position of the other piston, causes the opening of a hydraulic fluid bypass by said closure member and prevents further movement of said one piston until the fluid pressure acting thereon is reversed.

2. Apparatus according to claim 1 including second conduit means communicating a source of pressurized iiuid with the end of said cylinders opposite the ends thereof coupled by said first conduit means, control valve means disposed in said second conduit means for alternatingly coupling said source 'with one or the other of said cylinders, solenoid means operating said control valve means, and a solenoid actuator comprising a rod coupled to one of said pistons, projecting past a cylinder end and including solenoid actuating members disposed on the portion of the rod projecting past said cylinder end.

3. Apparatus according to claim 2 wherein said solenoid actuating rod moves over a distance substan- 6 tially less than the length of a work stroke of said one piston, wherein said one piston includes an axial bore axially movably mounting said rod, and wherein said rod includes spaced-apart rst and second piston engaging members for causing said limited axial movement of said solenoid actuating rod.

4. In an Iapparatus for pumping con-crete aggregate and having a pair of reciprocating plungers slidably disposed in chambers for movement of the plungers in charge and discharge strokes, a hydraulic actuator for eachuof the plungers, the hydraulic actuators including axially movable pistons disposed in cylinders, and control means for alternatingly pressurizing one or the other side of the pistons, the improvement comprising: valve means mounted to at least one of the pistons and having a closure member positioned to close a passageway iiuidly communicating portions of the cylinder disposed on each side of the one piston;

means for biasing the closure member in a passage closing position, and means acting in opposition to the biasing means for moving the closure member into its passage opening position in response to an out-of-phase relationship between the pistons, lwhereby a uid pressure build-up in the pressurized por- 'tion of the cylinder due to an out-ofJphase movement of the one piston disposed in the cylinder is prevented and pressurized fluid is permitted to drain through the passageway to the unpressurized portion of the cylinder until the pistons are in phase again.

References Cited UNITED STATES PATENTS 2/ 1942 Vickers 103-49 9/ 1945 Longenecker.

l/ 1946 Fitzgerald.

12/1961 Shimatanl et al. 10/1962 Handl 103-167 FOREIGN PATENTS 131,217 2/1949 Australia.

HENRY F. RADUAZO, Primary Examiner U.S. C1. X.R.

Images