US1633035A - Pump loading and unloading mechanism - Google Patents

Description

June 21, 1927. 1,633,035

P. W. RECK PUMP LOADING AND UNLOADING MECHANISM Filed Dec. 11, 1926 2 Sheets-Sheet l Fig-1 I Peck HZZDT'ITZEFS,

June 21 1927.

P. w. RECK PUMP LOADING AND UNLOADING MECHANISM Filed Dec. 11, 1926 2 Sheets-Sheet 2 InUEnZar'.

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Patented June 21, 1927.

UNITED STATES PATENT OFFICE.

PETER W. RECK, O1 IBETTENDORF, IOWA, ASSIGNOR TO THE BETTENDORR COMPANY,

OF BETTENDORF, IOTA, A CORPORATION OF IOWA.

PUMP LOADING AND UNLOADIN G MECHANISM.

Application filed December 11, 1926. Serial No. 154,128.

This invention relates to pumps and particularly to control devices for loading and unloading pumps for high pressure service.

It has heretofore been common practice to continuously operate reciprocating pressure again load the pump. The present invention contemplates an improved control mechanism for governing the operation of the intake or suction valvesof pumps of the above character.

Valve control mechanism has heretofore been proposed for loading and unloading pumps of the above character in such manner as to gradually increase or gradually reduce the torque imposed on the crank shaft of the pump by lifting or releasing the suction valves of the pump in prearranged sequence at a particular stage in the pumping cycle of each cylinder. Certain of the previously proposed mechanism positively holds the intake valves of the ump in their open position after they are ifted by the intake suction of the pumps. The operation of these systems is uncertain because the intake suction of the pump is required to lift the intake valves to substantially their full open position before the valve holding mechanism operates. It will be apparent that, if the lift of the intake valve is less than its full open stroke, or if the valve sticks, the pump will continue to develop pressure. The dangers incident to such uncertainty of operation of hydraulic pumps handling ressures, which at times exceed several tiousand pounds er square inch, will be apparent to those s illed in the art.

Valve control mechanism has also been proposed heretofore in which the intake valves are opened by the application of -yielding spring pressure that acts through a rocker arm againstthe push rod of the'valve and the internal pressure in the pump cylinder. The intake valves of these systems are yieldingly held in their open position when the pump is unloaded and they often close against the yielding force of the valve actuator during the pressure stroke of the pump with consequent severe water hammer which imposes enormous strains on the pumping equipment and defeats the purpose of regulated sequence control. For the above reasons, neither of the previously proposed methods of control of the intake valves of systems of the character herein described have been commercially practical.

The present invention proposes mechanism for yieldingly opening the intake valves of the pump, in order that the valves will be opened only during the intake stage of the pumping cycle, and also provides mechanism for positively holding the valve in its open position after actuation. The proposed mechanism can be used without or in connection with a sequence control system for selpctively loading the several pump cyl- 1n ers.

The primary object of the invention is to provide a system of control for reciprocating pumps of the above character that yieldingly opens the intake valves of the pump during the intake stage only andthat positively locks the valve in its after actuation.

Another object of the invention is to provide reliable positively actuated means for open position i loading or unloading the pump that is commerciall practicable and that is adapted to gradually apply or reduce the operating torque imposed on the crank shaft of the pump in loading and unloading operations.

Another object of the invention is to provide improved cam actuated mechanism for positively actuating the intake valve as quickly as the pressure within the pumping cylinder is reduced td a value that can be overcome by the regulated pull of a control spring or other yielding valve actuator.

Other objects and advantages to be derived from practicing the invention will be apparent to those skilled in the art from consideration of the accompanying description of a referred embodiment of the invention as illustrated in the accompanying drawings wherein:

Figure 1 is a sectional elevational view, taken on line 1-1 of Fig. 2, of a portion of v the cylinder block and intake valve mechanism of an accumulator pump constructed in accordance with this invention. I

F 1g. 2 IS an enlarged side elevational View of the control mechanism for one of the cylinders of the pump shown in Fig. 1.

Fig. 3 is an enlarged detail sectional 'view taken substantially on line 3--3 of Fig. 1 looking in the direction of the arrows and showing the cam mechanism for actuating the inlet valve. The cam -mechanism is shown in this view in the loaded position of the pump; and

Fig. 4 is a similar View of the sectional cam mechanism shown in the position in which the pump is unloaded, indicating in dotted outline the intermediate transition position of the cam.

For the purpose of illustrating the invention, it is shown as embodied in a conventional form of Blake horizontal duplex double acting reciprocating pressure pump intended for use in developing relatively high hydraulic pressures.

The illustrated portion of the pump comprises 'a cylinder block 1 that has a pressure developing" reciprocating piston 2 operating within a cylinder or pressure chamber 3 of ,the pump. A conventional form of connecting rod 4 serves to operate the piston. Liquid is admitted to the pump through inlet valves 5, each of which has a valve seat 6, a guide 7 and a push rod 8 associated therewith. There may be one or moreof these valves for each cylinder of the pump, depending upon the character of pump to which the invention is applied. The remainder of the pump structure is of conventional design, embodying any desired number of duplicate pump elements, as will be understood by those skilled in the art. The remainder of the pump structure is not illustrated herein because it would serve only to complicate the description of the present invention. I

The loading and unloadingof each cylinder orv pressure chamber of the pump is controlled from one or more duplicate valve actuating mechanisms, of which the cam mechanisms 9 and 10 that are governed by a solenoid 11 and a control spring 12 that is associated therewith, are representative. This cam mechanism and the associated control for governing the intake valves of the pump constitutes the particular subject matter,of the present invention. The solenoids of the system are preferably althou%h not necessarily energized. in prearrange sequence b any suitable control mechanism (not shown as will be apparent to those skilled in the art.

Each solenoid, when energized, serves to lift the crank pins 19 of a pair of bell cranks 13, to which connecting rods 14 of the solenoid extend, against the compressive force of the control spring 12. The control spring 12 normally serves to maintain the pump cylinder in its unloaded condition when the associated solenoid is deenergized. Each bell crank is carried at one end of a cam shaft 15 that has a cam 16 secured to the other end thereof. The. cam 16 engages the cooperating face of a second pivotally,

out substantial development of pressures in the pumping chamber.

The contacting surfaces of the cams 16 and 17 are so related as to facilitate actuation of the cam arm 17 by the operating cam 16 to substantially a dead center position with respect to the opposing thrust on the push rod 8. The are of movement of the crank arm is relatively small so that it is always in position to effectively control movement of the cam 16 to its extreme oper ative positions. In order to more clearly illustrate this relation of the cams 16 and 17, a dash and dot line 17 a is drawn between the contact centers of the cam arm 17 and a corresponding line 16 is drawn through the center of the contacting surfaces of cams 16 and 17 normal to the line 17 The relation of these lines show a desired substantially dead center position of the cams with respectto the push rod 8 and also show a preferred angularity of the contacting surfaces that facilitates actuation of the cams in each direction of movement.

The dotted outline 16 and 17 of the respective cams 16 and 17 illustrates the transition position of the cams when the internal pressure of the pump chamber prevents ac-' tuation of the push rod 8. The transition position of the cams is such that yielding lifting pressure is applied to the push rod 8.

The actuation of the valve does not take place, however, until the pressure in the pump cylinder is less than the force thus applied which prevents actuation of thevalve when the cylinder is loaded. After actuation of the valve, however, an enormous force on the push rod 8 would be required to move the cams a ainst the force of the control spring 12. is insures positive locking of the valve in its open position by mechanism adapted to apply yielding lifting force thereto.

The range of movement of the crank arm 13 is diagrammatically illustrated in'Fig. 3

and Fig. 4 by the change in position of the of the mechanisms 9 and 10 are mounted in a support 21 that has a flanged base 22 that is secured to the pump frame 23 by suitable nuts 24. A stuifing box 25 prevents leakage from the liquid supply along the cam shaft 15.

' The cam 17 is maintained on its pivot pm 27 by a suitable bracket 28 that is carried on an extension 29 of the support 21. The extension 29 also provides a guide for the lower end of the push rod 8.

If it is assumed that the pump is operating' to develop pressure, that is with the valve control mechanism in the position shown in Fig. 1, Fig. 2 and Fig. 3, and it IS desired to unload the pump because the accumulator pressure has reached a predetermined operating value or for any other reason, the solenoid 11 is deenergized which causes the operating spring 12 to rotate the chamber of the pump cams 16 and 17 to the transition positions 16 and 1?". In this position of the cams a predetermined operating force is yieldingly applied to the push rod 8 in a direction tend U5 mg to open the associated valves 5 against the internal pressure of the cylinder 3. This yielding pressure from the spring 12 is transmitted through the crank arm 13 and crank shaft 15 to the cam 16 which it tends to rotate-in the direction of the arrow 30 that is shown associated therewith in Fig. 3 of the drawings. The cam arm 17, which the cam 16 tends to lift, engages the adjacent end of the valve push rod 8. If the internal pressure of the pressure chamber 3 exceeds t e yieldingly applied pressure from-the spri. g 12 on the push rod 8, then the cams rema n in the transition stage indicated in the dotted outline positions 16 and 17 of Fig. l and the valves remain seated until the conclusion of the pressure stroke.

After the completion of the pressure stage of the pumping cycle, the pressure within the pumping chamber 3 is reduced to a value less than the yielding pressure imposed on the push rods 8. This permits the earns 17 to pass through the transition positions 16* v and 17 and to lift the associated valves 5 against the internal pressure of the pump cylinder to thereb unload the pump. Any desired number OI intake valves for a pressure chamber can be controlled from a single solenoid or other suitable actuating mechanism.

If a single control mechanism is used for deener 'zing all of the actuating solenoids 11 of t e pump mechanism, or if an equivalent mechanical control unit is used to simultaneously release or release in sequence the upward ull on crank arms 14 that act against t e spring 12, then the load on the pumping system is released simultaneously or in sequence except as to those pressure chambers of the pump that are 0 crating in the pressure developing stage of their pumpparticular cylinders that by the 'as applicant is aware. Applicants art that this release of the load on the pump will be much faster than a release that is dc pendent upon the lifting of the valves 5 by thesuction stroke of .the pump before the valves are'locked in their open positions. Every cylinder is unloaded except those are in the pressure developing stage of their cycle. Formerly the respective cylinders were not unloaded until the cycle of operation of each cylinder passed well into the intake stage of the pumping operation and the release at this stage was dependent upon substantially the full movement of the intake valve by the suction of the pump, making the release of the load uncertain.

- It will also beapparent to those skilled in the art that the lifting of the intake valves yielding force of the springs 12 provides a certainty of operation of the valve control mechanism that cannot otherwise be obtained and that the positive locking of the valve in its lifted position by so relating the cam faces as to positively lock the valve in its open position against all pressures to which the valve can be subjected, recludes premature closure of the intake va ve when it is held in its open position.

In again loading the pump, the solenoids 11 are successively energized at the termination of the pressure stroke or during the intake stroke by suitable control mechanism, or an equivalent mechanical device serves to successively actuate the connecting. rods 14. against the compressive force of the springs 12 to successively rotatethe crank arms to the positions shown in Figs. 1, 2'and 3, thereby permitting the intake valves 5 to seal only at the termination of their intake strokes. The load on the pump is thereby gradually applied because the intake valves 5 will take a position corresponding to the position of each cylinder in the pumping cycle. The advantages of providing cam actuated mechanism that is suitable for commercial use in pump structures of the types herein proposed will be apparent to those skilled in the art;

This is the only form of satisfactorily operating valve'control mechanism that is com mercially in use at the present time so far proposed cam acting valve lift is so designed and arranged as to give reliable operation of the valve at all times. The mechanism permits an effective seal to be formed between the operating solenoid and the valve lift mechanism that is mounted within the supply chamber of the pump. .The specific form of cam members are also arranged to cooperate "with very little frictional resistance. It also will be obvious that the release of the pump load is much quicker in applicants device than in apparatus heretofore proposed with all of the advantages of distributed reduction in the torque load imposed on the crank shaft of the pump.

pressure stage of the pumping cycle whereby said valve is actuated by said mechanism only when the actuating force applied to the push rod is less than the opposing force of the internal pressure of the pressure chamher acting on said valve, said mechanism' comprising a bell crank actuated by said pressure means, a cam shaft on which the bell crank'is mounted, a stufling box throu h which the shaft extends, a cam carried y the cam shaft remote from the bell crank, and a second pivotally mounted cam actuated by the first cam to impose lifting force on. the push rod when the cam shaft is actuated.

2. The combination with a pump having a pumping chamber, a suction valve, and a push rod for lifting said I valve from its seat, of mechanism for loading and unloading the pump comprising a pivotally mount ed cam arm adapted to act against said push rod to lift the valve, a second cam adapted to actuate the first cam, a shaft for the second cam, a stufling box for the shaft, a bell crank on one end of the shaft, and means for yieldingly operating the bell crank to lift the suction valve of the pump.

3. The combination with a pump having a pumping chamber, a suction valve, and a push rod for lifting said valve from its seat, of mechanism for loading and unloading the pump comprising a pivotally mounted cam arm adapted to act against said push rod to lift the valve, a second cam adapted to actuate the first cam, a shaft for the second cam, and means for yieldingly operating the first cam to lift the suction valve of the pump.

4. The combination with a pump havin a pumping chamber, a suction valve, an a push rod for lifting said valve from its seat, of mechanism for loading and unloading the hydraulic pump having pump comprising a pivotally mounted cam arm adapted to act against said push rod to lift the valve, a second cam adapted to actuate the first cam, a shaft for the second cam, and means for yieldingly operatin the first cam to lift the suction valve 0? the pump, said second cam being adapted to move to substantially a dead center position with respect to the force on the push rod when the valve is held in its full open position.

5. The combination with a reciprocating hydraulic pump having a pressure chamber, a liquid supply chamber, a suction valve between the chambers, and a push rod for lilting said valve from its seat, of pump loading and unloading mechanism comprising a solenoid, a bell crank actuated by the solenoid, means yieldingly opposing the actuation of the bell crank by the solenoid, a cam actuated by the bell crank, a second pivotally mounted cam arm actuated by the first cam and adapted to exert yielding valve lifting pressure upon-said push rod.

6. The combination with a reciprocating hydraulic pump having a pressure chamber, a liquid supply chamber, a suction valve between the chambers, and a push rod for lifting said valve from its seat, of pump loading and unloading mechanism comprising means for imposing yielding valve lifting force on the push rod adaptedto substantially lock the valve in its raised position after actuation by said yielding force, and means rendering said first means inoperative.

.7. The combination with a reciprocating hydraulic pump having a pressure chamber, a liquid supply chamber,,and a suction valve between the chambers, of. pump loading and unloading mechanism comprising means for yieldingly lifting the valve by application of a force of materially lesser magnitude than the force applied to said valve during the pressure stroke-of the pump and for substantially locking said valve in its raised position after its yielding actuation, and control means for rendering said valve lifting means inoperative.

38. The combination with a reciprocating a pressure chamber, a liquid supply chamber, and a suction valve between the chambers, of pump loading and unloading mechanism comprising a. cam shaft having a bell crank on one end and a cam on the other end thereof, a connecting rod for actuating the bell crank, a control spring acting to rotate said cam shaft, and means under the control of the operator for rendering said control spring inoperative'to rotate said cam shaft.

9. The combination with a reciprocating hydraulic pump having a pressure chamber, a liquid supply chamber, and a suction valve between the chambers, of pump loading and unloading mechanism comprising a pivot- Ill ally mounted arm adapted to apply lifting force to said valve, a cam acting on the arm to actuate the same into lifting engagement with the valve and for yieldingly holding I the cam in actuating relation in respect to the valve, and means for rendering said mechanism inoperative.

10. The combination with a reciprocating hydraulic pump having a pressure chamber, 10 a liquid supply chamber, and a suction valve between the chambers, of pumploading and unloading mechanism comprising a push rod for controlling said intake valve, a rocker arm acting on the push rod to lift the valve from its seat, a cam acting on the rocker arm, means normally tending to rotate said cam in a direction tending to lift said valve from its seat, and means for rendering said lifting means inoperative. Y

In testimony whereof I aflix my signature.

PETER W. RECK.

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