CN210290108U - Hydraulic balance reciprocating pump - Google Patents

Abstract

The utility model relates to a hydraulic balance reciprocating pump, including the pump body, valves and plunger subassembly, the pump body has inlet and liquid outlet, settle in the valves passageway of the pump body the valves and form with the communicating feed liquor chamber of inlet and with the communicating leakage fluid chamber of liquid outlet, still including the sealed letter assembly that sets up in the plunger passageway of the pump body, the plunger subassembly includes plunger rod and piston, the periphery wall and the sealed letter assembly of piston are sealed to be cooperated, the plunger rod axially movably wears to establish in sealed letter assembly and forms sealed cooperation at the back end of this plunger rod and sealed letter assembly, the periphery wall of the anterior segment of plunger rod with the piston with be formed with a balanced chamber that its volume can change along with the axial displacement of piston between the sealed letter assembly, still pack in the balanced chamber and have the first spring that can occupy the volume of this balanced chamber; the balance cavity is communicated with the liquid inlet cavity so that the fluid medium in the liquid inlet cavity enters the balance cavity and acts on the rear end face of the piston in a hydraulic mode.

Description

Hydraulic balance reciprocating pump

Technical Field

The utility model relates to a reciprocating pump technical field especially relates to a hydraulic balance reciprocating pump.

Background

The reciprocating pump is divided into a horizontal structure and a vertical structure and consists of a power end and a hydraulic end. In the process of conveying high-pressure liquid, the inlet pressure of the hydraulic end of the reciprocating pump is larger, the inlet pressure selected in part of application fields is more than 5MPa, and particularly the inlet pressure of a high-pressure booster pump used for the water injection working condition of an oil field is larger and is generally more than 10 MPa. Under the condition, the inlet pressure of the hydraulic end can react on the plunger, and in the operation process of the reciprocating pump, because the inlet pressure pushes the tip of the crosshead to be stressed in the axial pushing and pulling processes, oil supply gaps are not formed between the small end and the large end of the connecting rod of the power end and the crankshaft bush, so that the lubricating cannot be realized, and dry grinding heating of a power end moving part of the reciprocating pump can be caused.

In order to solve the above technical problems, a hydraulic balance reciprocating pump using a balance tube technology as a core has been widely developed in recent years. The hydraulic balance principle is that the plunger is set as a main and auxiliary structure, the annular area between the main plunger and the auxiliary plunger is utilized, the annular area is pressed by outlet pressure, the end face of the main plunger is subjected to inlet pressure when the main plunger is pulled backwards, and the annular area is subjected to the outlet pressure, so that a hydraulic balance condition is formed, and the shaft tip and the connecting rod copper bush can be separated from lubricating oil when the plunger is pulled backwards, so that the heating condition of a power end is reduced. For example, the application No. CN201320246303.2 (grant no:

CN203175839U) and the application number are: an adjustable combination valve hydraulic balance pump head of CN200720018970.X (the authorization publication number is CN201016329Y) discloses a hydraulic balance reciprocating pump applying the balance pipe structure.

However, the existing hydraulic balance reciprocating pump still has certain defects, the balance source of the balance pipe of the existing hydraulic balance reciprocating pump is led out from the liquid discharge cavity, when the existing hydraulic balance reciprocating pump is actually used on site, the pressure of an inlet and an outlet of the existing hydraulic balance reciprocating pump is changed, the difference between the design pressure and the implementation application pressure is large, the balance rate is difficult to reach 100 percent and generally ranges from 20 percent to 80 percent, and the problems of short service life of wearing parts, large vibration of the pump, high noise and the like often occur when the power end of the existing hydraulic balance reciprocating pump runs under the condition of low balance rate. Therefore, how to provide a hydraulic balance reciprocating pump which can ensure the normal operation of the power end of the pump without being limited by working conditions becomes a technical problem to be solved urgently by the technical field.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that to prior art's current situation, provide one kind and do not receive the operating mode condition restriction condition and can ensure its power end normal operating's hydraulic balance reciprocating pump.

The utility model provides a technical scheme that above-mentioned technical problem adopted does: a hydraulic balance reciprocating pump comprises a pump body, a valve group and a plunger component, wherein the pump body is provided with a plunger channel and a valve group channel which are communicated with each other, the pump body is provided with a liquid inlet and a liquid outlet, the valve group channel of the pump body is internally provided with the valve group and forms a liquid inlet cavity communicated with the liquid inlet and a liquid discharge cavity communicated with the liquid outlet, the plunger component is movably arranged in the plunger channel and further comprises a sealing box assembly arranged in the plunger channel of the pump body, the plunger component comprises a plunger rod and a piston arranged at the front end of the plunger rod, the peripheral wall of the piston is in sealing fit with the sealing box assembly, the plunger rod is axially and movably arranged in the sealing box assembly in a penetrating way, the rear section of the plunger rod is in sealing fit with the sealing box assembly, the peripheral wall of the front section of the plunger rod is in sealing fit with the piston and a balance cavity of which the volume can be changed along with the axial movement of the piston, the balance cavity is also filled with a first spring capable of occupying the volume of the balance cavity; the balance cavity is communicated with the liquid inlet cavity so that fluid medium in the liquid inlet cavity enters the balance cavity and acts on the rear end face of the piston in a hydraulic mode.

In order to communicate the liquid inlet cavity with the balance cavity, the sealing box body assembly comprises a main box body fixed in a plunger channel of the pump body, the main box body is a step cylinder with a small front part and a large rear part, a through hole is axially formed in the step cylinder, a first annular retaining shoulder is arranged on the inner wall of the plunger channel of the pump body, a step part of the step cylinder is abutted against the first annular retaining shoulder, the outer circle of the large cylinder of the step cylinder is in sealing fit with the inner wall surface of the pump body, and an annular flow channel is reserved between the outer circle of the small cylinder of the step cylinder and the inner wall surface of the pump body; the small cylinder of the step cylinder is provided with a first overflowing hole at the front part for communicating the through hole with the annular flow channel, and the small cylinder of the step cylinder is provided with a second overflowing hole at the rear part for communicating the annular flow channel with the balance cavity. When the piston moves forwards, part of the fluid medium in the fluid inlet cavity can enter the balance cavity through the first overflowing hole, the annular flow passage and the second overflowing hole in sequence; when the piston moves forwards, the fluid medium in the balance cavity can enter the liquid inlet cavity through the second overflowing hole, the annular flow passage and the first overflowing hole in sequence.

In order to realize that plunger subassembly carries out sealed cooperation with sealed letter body assembly at front and back both ends, and then guarantee that the fluid medium in the balanced chamber does not leak, sealed letter body assembly except the main letter body still include cylinder liner, vice letter body, packing subassembly, be equipped with the second annular on the inner wall of the perforating hole of main letter body and keep off the shoulder, this second annular keeps off the shoulder and divide into the first pore that is located the anterior segment and the second pore that is located the back end with this perforating hole corresponds the third of intercommunication and crosses the discharge orifice in the first pore, vice letter body is settled in the second pore, the plunger rod wears to establish vice letter body reaches in the cylinder liner, packing subassembly sets up seal both between the back end of plunger rod and vice letter body, the periphery wall of piston with the inner wall sealed cooperation of cylinder liner, the back end face of piston with annular region between the front end face of vice letter body constitutes balanced chamber And two ends of the first spring are respectively abutted against the rear end face of the piston and the front end face of the auxiliary box body. Because the front end of the first spring acts on the rear end face of the piston, the hydraulic pressure of a part of fluid medium in the liquid inlet cavity to the piston can be offset under the action of the elastic force of the first spring, the effect of assisting hydraulic balance is achieved, and the dry grinding heating of a power end moving part of the reciprocating pump is further reduced.

In order to ensure the sealing performance of the rear section of the plunger rod, the auxiliary box body is provided with an inner hole for accommodating the packing assembly, a third annular retaining shoulder is arranged on the inner wall of the front end of the inner hole of the auxiliary box body, and a compensating spring is further arranged between the packing assembly and the third annular retaining shoulder.

In order to firmly press all parts of the sealing box assembly in a plunger cavity of the pump body, the rear end of the sealing box assembly is also provided with a pressing cap component for pressing the sealing box assembly in a plunger channel of the pump body, and the pressing cap component comprises a first pressing cap for pressing the main box body on the rear end face, a second pressing cap for pressing the auxiliary box body on the rear end face and a third pressing cap for pressing the rear end of the packing component; the first pressure cap is connected to the inner wall surface of the plunger channel through external threads, a first internal thread hole is formed in the middle of the first pressure cap, the second pressure cap is connected to the first internal thread hole of the first pressure cap through external threads, a second internal thread hole is formed in the middle of the first pressure cap, and the third pressure cap is connected to the second internal thread hole of the second pressure cap through external threads, and a shaft hole for the plunger rod to penetrate through is formed in the middle of the third pressure cap. The structure arrangement can lead parts such as a main box body, a cylinder sleeve, an auxiliary box body, a packing component and the like of the sealing box body assembly to form an integrated structure with the plunger component, thereby greatly facilitating the assembly of the reciprocating pump.

In order to prevent the reciprocating pump from loosening during operation of the pressing cap assembly, the thread pitch between the internal thread and the external thread of the first pressing cap is different, and the thread pitch between the internal thread and the external thread of the second pressing cap is different.

In order to fully lubricate the piston and the cylinder sleeve and further prolong the service life of the piston and the cylinder sleeve, the middle part of the plunger rod is provided with a lubricating oil hole along the axial direction, the front end of the plunger rod is also provided with a radial oil hole communicated with the lubricating oil hole corresponding to the position of the piston, the peripheral wall of the piston is also provided with an annular lubricating flow passage, and the piston is also provided with a plurality of dispersing flow passages for communicating the radial oil hole with the lubricating flow passage.

The lubricating oil leakage is avoided while the lubricating between the piston and the cylinder sleeve is ensured, a sealing element in sealing contact with the cylinder sleeve is arranged in the middle of the outer peripheral wall of the piston, and a first guide belt and a second guide belt in sealing contact with the cylinder sleeve are respectively arranged at the front end and the rear end of the outer peripheral wall of the piston; the lubricating device comprises a first guide belt, a sealing piece, a second guide belt, a first lubricating flow channel, a second lubricating flow channel and a lubricating oil inlet, wherein the number of the lubricating flow channels is two, the first lubricating flow channel and the second lubricating flow channel are respectively a first lubricating flow channel and a second lubricating flow channel, the first lubricating flow channel is arranged between the first guide belt and the sealing piece, and the second lubricating flow channel is arranged between the second guide belt and the sealing.

As an improvement, the reciprocating pump is of a vertical structure, wherein the valve group is a combination valve, and the valve group channel and the plunger channel are coaxially arranged.

In a further improvement, the pump body is cylindrical as a whole and has a three-cylinder or multi-cylinder structure, namely three or more plunger channels.

Compared with the prior art, the utility model has the advantages that: the balance cavity in the hydraulic balance reciprocating pump in the utility model is communicated with the liquid inlet cavity of the reciprocating pump, namely, a hydraulic balance source is arranged in the liquid inlet cavity, because the balance cavity is communicated with the liquid inlet cavity, fluid medium entering the balance cavity can always act on the rear end surface of the piston to balance the inlet pressure of the front end surface of the piston, wherein, when the piston moves backwards, the balance between the front and rear end surfaces of the piston is inlet pressure, when the piston moves forwards, the balance between the front and rear end surfaces of the piston is exhaust pressure, namely, the annular area of the piston except the cross sectional area of the plunger rod is balanced at the front and rear ends, thereby avoiding the problem that the reciprocating pump in the prior art arranges the hydraulic balance source in the liquid discharge cavity and is difficult to effectively balance the front and rear ends of the piston, because the piston of the reciprocating pump is not influenced by the change of inlet and outlet pressure difference, therefore, the problems of short service life of easily damaged parts, large vibration of the pump, high noise and the like when the power end of the reciprocating pump runs under the condition of low balance rate can be effectively solved. And, the utility model provides a be equipped with first spring in the balanced chamber, wherein, the setting of this first spring can occupy the considerable partial volume of annular chamber, so can be used for compensating the volume loss of advancing, flowing back in-process of this reciprocating pump, can play the variable effect to balanced flow.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention;

fig. 2 is a schematic structural view of the sealing box assembly and the plunger assembly according to the embodiment of the present invention;

fig. 3 is a schematic structural diagram of a plunger assembly according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a main letter body according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view taken at A-A of FIG. 4;

fig. 6 is a schematic structural diagram of a pump body according to an embodiment of the present invention;

fig. 7 is a sectional view (three-cylinder structure) at a-a of fig. 6.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments.

Referring to fig. 1-7, a hydraulic balance reciprocating pump includes a pump body 10, a plunger assembly 20, a valve group 13 and a sealing box assembly, the pump body 10 includes a plunger channel 11 and a valve group channel 12 which are communicated with each other, wherein the valve group 13 is disposed in the valve group channel 12, the plunger assembly 20 includes a plunger rod 21 and a piston 22 disposed at a front end of the plunger rod 21, the plunger rod 21 can drive the piston 22 to slide back and forth in the plunger channel 11 under the action of a power end of the reciprocating pump, specifically, the sealing box assembly is disposed in the plunger channel 11, and the plunger assembly 20 is inserted into the sealing box assembly and is in sealing fit with the sealing box assembly.

In the present embodiment, the hydrodynamically balanced reciprocating pump is of a vertical type, with the plunger channel 11 and the valve block channel 12 being coaxially arranged, and in particular, the pump body 10 is of a cylindrical shape, and may be of a three-cylinder or multi-cylinder structure, in the present embodiment, the reciprocating pump is of a three-cylinder structure (see fig. 7 in detail), that is, the plunger channels 11 are three, and the valve block 13 and the sealing box assembly are arranged at the bottom of each cylinder. The pump body 10 has a liquid inlet 101 and a liquid outlet 102, the valve group 13 is a combination valve, a limit step 17 is arranged on the inner wall of the valve group channel 12 at the bottom of the pump body 10, the bottom surface of the valve body of the combination valve is limited on the limit step 17, and the sealing box assembly is located above the combination valve and is pressed on the top surface of the valve seat of the combination valve. The combination valve is assembled in the valve group channel 12 of the pump body 10, so that a liquid inlet cavity 103 and a liquid outlet cavity 104 are formed in the pump body 10, wherein when the reciprocating pump absorbs liquid, fluid media enter and exit from the liquid inlet 101 and enter the liquid inlet cavity 103 of the pump body 10 through the liquid inlet valve of the combination valve, and when the reciprocating pump discharges liquid, the fluid media in the liquid inlet cavity 103 enter the liquid discharge cavity of the pump body 10 through the liquid discharge valve of the combination valve and then are discharged through the liquid outlet 102, see fig. 1.

Referring to fig. 2, the sealing box assembly includes a main box body 41, an auxiliary box body 51, a packing component 52 and a pressing cap component, the main box body 41 is a stepped cylinder with a small front part and a large rear part, the stepped cylinder is provided with a through hole 410 arranged axially, the piston 22 component is movably arranged in the through hole 410, correspondingly, the inner wall of the plunger channel 11 of the pump body 10 is provided with a first annular retaining shoulder 14, when the stepped cylinder is assembled in the plunger channel 11, the stepped cylindrical step 413 can abut against the first annular retaining shoulder 14, the rear end surface of the stepped cylinder is pressed by the first pressing cap 61, wherein the first pressing cap 61 has an external thread and is connected to the inner wall of the pump body 10 through the external thread. When the step cylinder is assembled in place, the outer circle of the large cylinder 42 of the step cylinder can be in sealing fit with the inner wall surface of the pump body 10, the large cylinder 42 can be sealed through a sealing ring sleeved on the large cylinder 42, an annular flow channel 430 is reserved between the outer circle of the small cylinder 43 of the step cylinder and the inner wall surface of the pump body 10, and the annular flow channel 430 is communicated with the liquid inlet cavity 103 of the pump body 10.

The inner wall of the through hole 410 of the main body 41 is provided with a second annular shoulder 44, the second annular shoulder 44 divides the through hole 410 into a first hole 411 at the front section and a second hole 412 at the rear section (see fig. 4 in detail), wherein the first hole 411 is provided with the cylinder liner 50, the front end surface of the cylinder liner 50 is pressed on the top surface of the valve seat of the combination valve, and the rear end of the cylinder liner 50 is abutted against the second annular shoulder 44. When the cylinder liner 50 is placed in the first bore 411, the inner wall of the cylinder liner 50 is flush with the inner wall of the second annular shoulder 44 to form a smooth surface so that the piston 22 can smoothly slide back and forth within the main housing 41.

Referring to fig. 2, the second opening 412 is provided with the sub-housing 51, the front end surface of the sub-housing 51 abuts against the second annular shoulder 44, the rear end surface of the sub-housing 51 is pressed by the second pressing cap 62, specifically, the outer peripheral wall of the second pressing cap 62 has an external thread, the first pressing cap 61 has a first internal thread hole 610, and the second pressing cap 62 is screwed into the first internal thread hole 610 of the first pressing cap 61 to press the sub-housing 51 into the second opening 412 of the main housing 41. The compensating spring 53 and the packing assembly 52 are sequentially arranged in the inner hole 510 of the sub-box body 51 from front to back, specifically, the front end of the inner hole of the sub-box body 51 is provided with a third annular stop shoulder 511, the front end of the compensating spring 53 abuts on the rear end wall of the third annular stop shoulder 511, the rear end of the compensating spring 53 abuts on the packing assembly 52, wherein the packing assembly 52 comprises a sealing packing 522 and a corresponding guide ring 521, the rear end of the packing assembly 52 is pressed in the inner hole of the sub-box body 51 through a third press cap 63, specifically, the second press cap 62 is provided with a second internal threaded hole 620, the outer peripheral wall of the third press cap 63 is provided with external threads, and the third press cap 63 is screwed on the second press cap 62 so as to press the packing assembly 52 in the sub-box body 51. The first press cap 61, the second press cap 62 and the third press cap 63 are connected by a primary thread from outside to inside to form the press cap assembly, and the main casing 41, the auxiliary casing 51 and the packing assembly 52 are fixed in the plunger passage 11 of the pump body 10. The front end of the plunger rod 21 is connected to the piston 22 through the packing assembly 52 and the compensating spring 53 in the sub-housing 51, thereby sealing the rear end of the plunger rod 21 and preventing the fluid medium from leaking out of the rear end of the plunger rod 21. In addition, the internal and external thread pitches of the first press cap 61 and the internal and external thread pitches of the second press cap 62 are different, so as to prevent the press cap assembly from loosening during the operation of the reciprocating pump.

Referring to fig. 3, the piston 22 of the plunger assembly 20 is locked at the front end of the plunger rod 21 by a split cap, specifically, a sealing member 73 is arranged at the middle position of the outer circle of the piston 22, and guide belts are respectively arranged at both sides to guide and seal the inner cavity of the cylinder sleeve 50. Because the piston 22 is sealed with the cylinder sleeve 50 at the front part, the rear section of the plunger rod 21 is sealed with the main box body 41 through the packing assembly 52 and the auxiliary box body 51, so that an annular cavity, namely a balance cavity, is formed between the front section of the plunger rod 21 and the inner wall of the main box body 41, and the volume of the annular cavity can be continuously changed along with the back-and-forth movement of the piston 22, wherein a first overflowing hole 431 for communicating the through hole 410 and the annular flow passage 430 is formed at the front part of the small cylinder 43 of the main box body 41, a third overflowing hole 501 correspondingly communicated with the first overflowing hole 431 is formed on the cylinder sleeve 50 arranged in the through cavity of the main box body 41, namely the first overflowing hole 431 and the third overflowing hole 501 correspondingly communicate in the inner and outer directions, a second overflowing hole 432 for communicating the annular flow passage 430 and the balance cavity is formed on the small cylinder 43 of the main box body 41, in the embodiment, the second overflowing hole 432 is provided with a plurality of second annular retaining shoulders 44 correspondingly arranged on the main box body 41, specifically, a plurality of second overflowing holes 432 are uniformly arranged along the circumferential direction of the main body 41 (see fig. 5 in detail), and the fluid medium in the liquid inlet cavity 103 can enter the annular cavity through the third overflowing hole 501, the first overflowing hole 431, the annular flow passage 430 and the second overflowing hole 432 in sequence. The annular chamber region between the rear end face of the piston 22 and the front end face of the coupling body 51 thus forms a balancing chamber into which the fluid medium in the inlet chamber 103 can enter, the fluid entering this balancing chamber being able to act hydraulically on the rear end face of the piston 22. Meanwhile, in order to reduce the volume loss of the reciprocating pump, a first spring 31 is further arranged in the annular cavity, wherein two ends of the first spring 31 are respectively abutted on the rear end face of the piston 22 and the front end face of the auxiliary box body 51. In this embodiment, one or more first springs 31 may be disposed according to the volume of the annular cavity, and since the first spring 31 occupies a substantial part of the volume of the annular cavity, it can be used to compensate the volume loss during the liquid feeding and discharging process of the reciprocating pump, and it can have a variable effect on the balance flow rate, specifically, when the piston 22 moves forward, the first spring 31 expands, the volume of the annular cavity becomes larger, and a part of the discharged medium enters into the annular cavity, and when the piston 22 moves backward, the first spring 31 compresses, the volume of the annular cavity becomes smaller, and a part of the medium in the annular cavity is discharged into the suction cavity. In addition, the first spring 31 acts on the rear end surface of the piston 22, and can also counteract a part of hydraulic force of the fluid medium in the liquid inlet cavity 103 on the piston assembly 20, so as to assist hydraulic balance.

In this embodiment, during the liquid feeding and discharging process of the reciprocating pump, since the annular chamber is communicated with the liquid inlet chamber 103, the fluid medium entering the annular chamber can always act on the rear end face of the piston 22, so as to balance the inlet pressure of the front end face of the piston 22. Thus, the balance pressure on the front end surface and the rear end surface of the plunger relative to the corresponding annular area of the annular cavity is 100% balanced, namely the annular area of the piston 22 except the cross-sectional area of the plunger rod 21 is balanced on the front end surface and the rear end surface, wherein, when the piston 22 runs backwards, the balance between the front end surface and the rear end surface of the piston 22 is the inlet pressure, and when the piston 22 runs forwards, the balance between the front end surface and the rear end surface of the piston 22 is the discharge pressure, so the piston 22 of the reciprocating pump is not influenced by the pressure difference change between the inlet and the outlet.

Referring to fig. 3, in order to fully lubricate between the piston 22 and the cylinder sleeve 50 and further improve the service life of the piston 22 and the cylinder sleeve 50, a lubricating oil hole 70 for feeding lubricating oil is axially formed in the middle of the plunger rod 21, wherein guide belts are respectively arranged at two ends of an outer circle of the piston 22, a sealing member 73 in sealing contact with the cylinder sleeve 50 is arranged at a middle position on the outer circumferential wall of the piston 22, a first guide belt 74 and a second guide belt 75 in sealing contact with the cylinder sleeve 50 are respectively arranged at front and rear ends on the outer circumferential wall of the piston 22, and two lubricating flow passages are further arranged on the outer circle of the piston 22, specifically, a first lubricating flow passage 76 and a second lubricating flow passage 77 are respectively arranged, wherein the first lubricating flow passage 76 is arranged between the first guide belt and the sealing member, and the second lubricating flow passage 77 is arranged between the second guide. The two lubricating flow passages are communicated with a central lubricating oil hole 70 of the plunger rod 21, specifically, a radial oil hole 71 communicated with the lubricating oil hole 70 is further formed at the position, corresponding to the position of the piston 22, of the front end of the plunger rod 21, and a plurality of dispersing flow passages 72 for communicating the radial oil hole 71 with the lubricating flow passages are further formed in the piston 22. Thus, the lubricating oil can be introduced from the oil inlet hole at the upper end of the lubricating oil hole 70 of the plunger rod 21, and the lubricating oil is supplied between the outer circle of the piston 22 and the cylinder sleeve 50 through the radial oil hole 71 and the dispersion flow passage 72 to effectively lubricate the outer circle of the piston 22 and the cylinder sleeve 50, so that the service lives of the piston 22 and the cylinder sleeve 50 are prolonged. More specifically, at the intersection of the pump body 10 and the power end, a lubricating oil pool 15 and a running window 16 for observing the running of the plunger rod 21 and the intermediate rod are arranged in a running cavity of the upper part of the plunger rod 21 and the intermediate rod (not shown) of the power end, and lubricating oil stored in the lubricating oil pool can lubricate the seal between the plunger rod 21 and the packing assembly 52, so that the service life of moving parts such as the plunger rod 21 is prolonged.

Claims (10)

1. The utility model provides a hydraulic balance reciprocating pump, includes pump body (10), valves (13) and plunger subassembly (20) that have plunger passageway (11) and valves passageway (12) that communicate with each other, pump body (10) have inlet (101) and liquid outlet (102), settle in valves passageway (12) of pump body (10) valves (13) and form with the communicating feed liquor chamber (103) of inlet (101) and with the communicating flowing back chamber (104) of liquid outlet (102), plunger subassembly (20) activity is located in plunger passageway (11), its characterized in that: the plunger assembly (20) comprises a plunger rod (21) and a piston (22) arranged at the front end of the plunger rod (21), the outer peripheral wall of the piston (22) is in sealing fit with the sealing box assembly, the plunger rod (21) is axially and movably arranged in the sealing box assembly in a penetrating manner and forms sealing fit with the sealing box assembly at the rear section of the plunger rod (21),

an equilibrium cavity (30) with the volume capable of changing along with the axial movement of the piston (22) is formed between the outer peripheral wall of the front section of the plunger rod (21) and the piston (22) and the sealing box assembly, and a first spring (31) capable of occupying the volume of the equilibrium cavity (30) is filled in the equilibrium cavity (30);

the balance cavity (30) is communicated with the liquid inlet cavity (103) so that the fluid medium in the liquid inlet cavity (103) enters the balance cavity (30) and hydraulically acts on the rear end face of the piston (22).

2. The hydraulically balanced reciprocating pump of claim 1, wherein: the sealing box body assembly comprises a main box body (41) fixed in a plunger channel (11) of the pump body (10), the main box body (41) is a stepped cylinder with a small front part and a large rear part, and the stepped cylinder is provided with a through hole (410) arranged axially;

a first annular retaining shoulder (14) is arranged on the inner wall of a plunger channel (11) of the pump body (10), a step part (413) of the step cylinder abuts against the first annular retaining shoulder (14), the outer circle of a large cylinder (42) of the step cylinder is in sealing fit with the inner wall surface of the pump body (10), and an annular flow channel (430) is reserved between the outer circle of a small cylinder (43) of the step cylinder and the inner wall surface of the pump body (10);

the small cylinder (43) of the stepped cylinder is provided with a first overflowing hole (431) at the front part for communicating the through hole (410) with the annular flow passage (430), and the small cylinder (43) of the stepped cylinder is provided with a second overflowing hole (432) at the rear part for communicating the annular flow passage (430) with the balance cavity (30).

3. The hydraulically balanced reciprocating pump of claim 2, wherein: the sealing box body assembly comprises a cylinder sleeve (50), an auxiliary box body (51) and a packing component (52) besides the main box body (41), wherein a second annular retaining shoulder (44) is arranged on the inner wall of a through hole (410) of the main box body (41), the second annular retaining shoulder (44) divides the through hole (410) into a first hole (411) located at the front section and a second hole (412) located at the rear section, the cylinder sleeve (50) is arranged in the first hole (411) and is provided with a third overflowing hole (501) correspondingly communicated with the second overflowing hole (432), the auxiliary box body (51) is arranged in the second hole (412), the plunger rod (21) is arranged in the auxiliary box body (51) and the cylinder sleeve (50) in a penetrating manner, the packing component (52) is arranged between the rear section of the plunger rod (21) and the auxiliary box body (51) to seal the two, the outer peripheral wall of the piston (22) is in sealing fit with the inner wall of the cylinder sleeve (50), an annular area between the rear end face of the piston (22) and the front end face of the auxiliary box body (51) forms the balance cavity (30), and two ends of the first spring (31) are respectively abutted to the rear end face of the piston (22) and the front end face of the auxiliary box body (51).

4. A hydraulically balanced reciprocating pump according to claim 3, characterized in that: the auxiliary box body (51) is provided with an inner hole (510) for accommodating the packing component (52), a third annular retaining shoulder (511) is arranged on the inner wall of the front end of the inner hole (510) of the auxiliary box body (51), and a compensation spring (53) is further arranged between the packing component (52) and the third annular retaining shoulder (511).

5. The hydraulically balanced reciprocating pump of claim 4, wherein: the rear end of the sealing box body assembly is also provided with a press cap component used for pressing the sealing box body assembly in a plunger channel (11) of a pump body (10), and the press cap component comprises a first press cap (61) used for pressing the rear end face of the main box body (41), a second press cap (62) used for pressing the rear end face of the auxiliary box body (51) and a third press cap (63) used for pressing the rear end of the packing component (52);

first pressure cap (61) through threaded connection on the internal wall face of plunger passageway (11) and be formed with first internal thread hole (610) in the middle part, second pressure cap (62) through threaded connection in first internal thread hole (610) of first pressure cap (61) and form second internal thread hole (620) in the middle part, third pressure cap (63) through threaded connection in second internal thread hole (620) of second pressure cap (62) and form shaft hole (630) that supply plunger rod (21) to pass in the middle part.

6. The hydraulically balanced reciprocating pump of claim 5, wherein: the thread pitch between the internal thread and the external thread of the first pressing cap (61) is different, and the thread pitch between the internal thread and the external thread of the second pressing cap (62) is different.

7. A hydraulically balanced reciprocating pump according to any of claims 3-6, characterized in that: the middle part of the plunger rod (21) is provided with a lubricating oil hole (70) along the axial direction of the plunger rod, the front end of the plunger rod (21) is further provided with a radial oil hole (71) communicated with the lubricating oil hole (70) at the position corresponding to the piston (22), the outer peripheral wall of the piston (22) is further provided with an annular lubricating flow passage, and the piston (22) is further provided with a plurality of dispersing flow passages (72) used for communicating the radial oil hole (71) with the lubricating flow passage.

8. The hydraulically balanced reciprocating pump of claim 7, wherein: a sealing piece (73) in sealing contact with the cylinder sleeve (50) is arranged in the middle of the outer peripheral wall of the piston (22), and a first guide belt (74) and a second guide belt (75) in sealing contact with the cylinder sleeve (50) are respectively arranged at the front end and the rear end of the outer peripheral wall of the piston (22);

the lubricating device comprises two lubricating flow passages, namely a first lubricating flow passage (76) and a second lubricating flow passage (77), wherein the first lubricating flow passage (76) is arranged between the first guide belt (74) and the sealing element (73), and the second lubricating flow passage (77) is arranged between the second guide belt (75) and the sealing element (73).

9. The hydraulically balanced reciprocating pump of claim 1, wherein: the reciprocating pump is of a vertical structure, wherein the valve group (13) is a combination valve, and the valve group channel (12) and the plunger channel (11) are coaxially arranged.

10. The hydraulically balanced reciprocating pump of claim 9, wherein: the pump body (10) is cylindrical as a whole and has a three-cylinder or multi-cylinder structure, namely three or more plunger passages (11).

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