WO2013037198A1

WO2013037198A1 - Water plunger pump and hydraulic control system thereof

Info

Publication number: WO2013037198A1
Application number: PCT/CN2012/071111
Authority: WO
Inventors: 史先信; 冯瑜; 徐小东; 赵阳光
Original assignee: 徐州重型机械有限公司
Priority date: 2011-09-14
Filing date: 2012-02-14
Publication date: 2013-03-21
Also published as: BR112014005904A2; RU2579540C2; AU2012308005A1; RU2014113204A; CN102330649A

Abstract

Disclosed in the present invention is a water plunger pump has two plunger groups (1, 2) each comprised bynsists of a water cylinder (11, 12) and an oil cylinder (12, 22). A water cylinder piston and an oil cylinder piston of each plunger group (1, 2) move synchronously, and the water port of each water cylinder canister (111, 211) is provided with a water inlet check valve (12, 23) for unidirectionally admitting from the outside to the inner cavity of the canister and a water outlet check valve (14, 24) for unidirectionally admitting from the inner cavity of the canister to an outside water outlet. Two oil cylinders (12, 22) are configured to alternatively stretch under the control of a control valve. Said water plunger pump breaks through the configuration and principle of the traditional water pump and enables switching between two working states by alternative movement of two water cylinder pistons which are driven by alternative stretch of two oil cylinders (12, 22). Compared with the prior art, based on supplying water without interruption, said water plunger pump can enhance outlet flow and water pressure. Based on this, a hydraulic control system of said water plunger pump is provided.

Description

The utility model relates to a plunger water pump and a liquid control system thereof. The application is filed on September 14, 2011, the Chinese Patent Office, the application number is 201110272366.0, and the invention name is "a plunger pump and its liquid control system". Priority is hereby incorporated by reference in its entirety. Technical field

The invention relates to engineering machinery technology, in particular to a plunger water pump and a liquid control system thereof. Background technique

As the overall height of commercial and residential super-tall buildings continues to rise, one of the challenges of their fire protection systems is the difficulty of water supply. It is well known that the fire water supplied by most fire water sources requires a water pump to pressurize to meet the water pressure and water requirements during fire fighting. For example, in the case of a mobile fire truck, it is usually installed with a fire pump to provide pressure water for fire extinguishers such as fire water guns and fire water cannons. Obviously, a well-functioning fire pump plays a decisive role in the development of fire-fighting tactics and the implementation of fire-fighting methods.

In the prior art, the fire pump used for water supply mainly has two types of centrifugal water pump and plunger water pump; due to its own structure limitation, the two can only send water to a height of about 100 meters, which occurs in a super high-rise building. After the fire, due to insufficient water supply pressure and flow, the water source cannot be effectively transported in time, so that the fire cannot be controlled, which often results in very large loss of life and property. Among them, the centrifugal water pump has leakage and backflow problems during the working process. With the increase of the outlet pressure, the leakage and return flow increase synchronously, and the outlet pressure is difficult to reach the standard of the high pressure fire pump rated pressure not less than 4.0 MPa, and the working efficiency is reduced; The working principle of the plunger pump limits its output flow to generally not exceed lOL/s, which cannot meet the requirements of fire fighting water consumption for super high-rise buildings.

In view of this, it is urgent to find another way to optimize the design of the pump to meet the requirements of the fire pressure and output flow of fire fighting water in super high-rise buildings. Summary of the invention

In view of the above drawbacks, the technical problem solved by the present invention is to provide a plunger water pump to reliably increase the output pressure and flow rate of the water pump to meet the fire fighting requirements of super high-rise buildings. Based on this, the present invention also provides a hydraulic control system for the plunger water pump. The plunger water pump provided by the invention comprises two plunger groups consisting of a water cylinder and a cylinder, the water cylinder piston of each plunger group is synchronously displaced with the cylinder piston, and is connected with the nozzle of each cylinder cylinder. There is a water inlet check valve which is single-passed from the outside to the inner cavity of the cylinder cylinder, and a water outlet check valve which is single-passed from the cylinder inner chamber to the outer water outlet; the two cylinders are arranged to alternate under the control of the control valve Telescopic.

Preferably, a water tank is further included, and the two water tanks are built in the water tank.

Preferably, a through hole communicating with the water tank is opened on a side wall of the cylinder bore of the outer end of the rod chamber having the rod chamber.

Preferably, the external water outlet is located at the end of the water outlet pipe that communicates with the two outlet water one-way valves.

The hydraulic control system of the plunger water pump provided by the present invention comprises a pressure oil circuit and a return oil circuit, and the control valve is configured to have two working positions: in the first working position, the pressure oil path and the first The rodless cavity of the oil cylinder and the rod cavity of the second oil cylinder are connected, and the oil return oil passage is connected with the rod cavity of the first oil cylinder and the rodless cavity of the second oil cylinder; in the second working position, the pressure oil passage and the first oil cylinder The rod chamber and the rodless chamber of the second cylinder communicate with each other, and the return oil passage communicates with the rodless chamber of the first cylinder and the rod chamber of the second cylinder.

Preferably, the control valve is specifically: a first hydraulic directional valve disposed between the two chambers of the first cylinder and the pressure oil passage and the return oil passage, and two chambers and a pressure oil passage disposed in the second cylinder And a second hydraulic directional valve between the oil returning passage; and, the two cylinders are provided with a receiving oil port communicating with the inner cavity of the cylinder barrel, and the receiving oil port is located between the end of the rodless cavity The distance from the cylinder bore of the first cylinder is connected to the control port of the first pilot directional valve and the second pilot directional valve to drive the first The hydraulic directional valve and the second hydraulic directional valve are respectively located at the first working position and the second working position, and the control oil port of the second cylinder and the control of the first hydraulic directional valve and the second hydraulic directional valve The oil port is connected to drive the first hydraulic directional valve and the second hydraulic directional valve respectively at the second working position and the first working position.

Preferably, the method further comprises two receiving valves respectively disposed between the two oil cylinders and the corresponding hydraulic directional valve, the oil inlet of each of the receiving valves is connected with the corresponding oil port of the corresponding oil rainbow, the pressure balance oil port and the corresponding oil cylinder The oil port of the rod cavity is connected, and the oil outlet is connected with the control oil port of the corresponding hydraulic directional valve. Preferably, the bottoms of the cylinders of the two cylinders are provided with a buffer bypass that is unidirectionally guided in the retracting direction of the piston, and the oil outlet of the buffer bypass communicates with the inner cavity of the cylinder through the bottom of the cylinder cylinder. The oil inlet of the buffer bypass communicates with the cylinder bore through a side wall of the cylinder at a distance from the bottom of the cylinder that is greater than the length of the cylinder piston.

Preferably, the pressure oil passing through the first hydraulic directional valve and the first oil rainbow is routed to the first pump for oil supply, and the pressure oil connected to the second oil cylinder via the second hydraulic directional valve is routed to the second pump. Oil; and, an overflow valve is provided between the outlet of the two pumps and the return oil passage.

Preferably, the overflow is specifically an electrically controlled relief valve.

The plunger water pump provided by the invention comprises two plunger groups consisting of a water cylinder and a cylinder, and the water cylinder piston of each plunger group is synchronously displaced with the cylinder piston, that is, the hydraulically controlled double plunger pump; The nozzles of the cylinder are connected with a water inlet check valve that is single-passed from the outside to the cylinder bore, and the water outlet is unidirectionally wide from the cylinder bore to the external water outlet, and the two cylinders are configured to Alternately expand and contract under the control of the control valve. Compared with the prior art, the invention breaks through the structural principle of the traditional water pump, and adopts two oil cylinders to alternately advance and retreat, thereby driving the two water cylinder pistons to alternately operate, thereby respectively realizing the switching of the two working states: First, The water inlet connected to the nozzle of the first cylinder cylinder is unidirectionally wide and non-conducting, and the water outlet is unidirectionally wide-conducting, and the inlet water communicating with the nozzle of the second cylinder cylinder is unidirectionally wide-conducting and the water outlet is one-way wide. In this state, the first cylinder cylinder drains and the second cylinder cylinder absorbs water. Secondly, the inlet water communicating with the nozzle of the first cylinder cylinder is unidirectionally wide-conducting, and the outlet water is unidirectionally wide and non-conducting, and the inlet water communicating with the nozzle of the second cylinder cylinder is unidirectionally wide and non-conducting, The outlet check valve is turned on; in this state, the first water rainbow tube absorbs water, and the second water rainbow tube drains. The water cylinder piston and the cylinder cylinder of the invention can have an actual and reliable sealing structure, which can effectively prevent internal leakage; therefore, the present invention can effectively improve the output flow on the basis of continuous intermittent water supply by the above-mentioned structural optimization design. And water pressure, through production test, this program can fully meet the requirements of super high-rise building fire extinguishing water pressure 8.0MPa and output flow rate 40L / S.

In a preferred embodiment of the present invention, a through hole communicating with the water tank is opened on the side wall of the cylinder bore of the outer end of the rod chamber of the water cylinder, and on the one hand, the through hole can be used to balance the movement of the piston of the water cylinder The cylinder of the water cylinder has a pressure generated by the volume change in the rod cavity, that is, when the cylinder piston advances in the cylinder barrel, the cylinder piston has a volume on the rod chamber side to generate a vacuum, and the external water enters through the through hole; Conversely, when the cylinder piston retreats within the cylinder, the cylinder piston has a smaller volume on the rod chamber side to generate pressure, and water is forced out from the through hole. In addition, water can enter and exit from the through hole, thereby cooling the cylinder piston rod connected to the water rainbow piston, and the piston rod can cool the hydraulic oil, thereby effectively controlling the heat dissipation of the hydraulic system.

In a preferred embodiment of the plunger pump hydraulic control system provided by the present invention, both cylinders are provided with a receiving oil port communicating with the inner cavity of the cylinder barrel, and the receiving oil port is configured to be rodless at a time when the corresponding oil rainbow is completely extended. The cavity side of the first hydraulic directional valve is connected with the oil receiving port of the first hydraulic cylinder, and the control oil port of the second hydraulic directional valve is connected with the second oil red receiving oil port. That is, when the piston protrudes to the end of the stroke, the pressure oil corresponding to the drive piston will be fed back to the control end of the directional valve of the other cylinder, thereby driving the spool to reverse, and vice versa; The force automatically controls the alternate extension and retraction of the two cylinders, and has the characteristics of reliable operation. Preferably, the take-off valve is disposed between the corresponding fetching port and the control valve, which can further improve the working reliability of the hydraulic reversing; meanwhile, when the cylinder piston is close to the extended limit position, the pressure-free oil of the rod-free cavity can pass through the fetching valve One-way flow to the rod cavity, thereby avoiding the impact of the protruding terminal, affecting the stability of the system work.

The plunger water pump and the liquid control system provided by the invention are suitable for any fire fighting equipment and system.

DRAWINGS

1 is a schematic view showing the overall structure of the plunger water pump in a specific embodiment;

2 is a schematic structural view of a cylinder cylinder of the specific embodiment;

3 is a schematic diagram of the plunger pump hydraulic control system in a specific embodiment.

In the picture:

The first plunger group 1, the first 7J cylinder 11, the first 7J cylinder cylinder 111, the first cylinder 12, the credit port 121, the first oil rainbow piston 122, the first water inlet check valve 13, the first water outlet The check valve 14, the second plunger group 2, the second water tank 21, the second cylinder cylinder 211, the second cylinder 22, the credit port 221, the second oil rainbow piston 222, and the second water inlet check valve 23. The second water outlet check valve 24, the water tank 3, the water outlet pipe 4, the first hydraulic control directional valve 51, the second hydraulic control directional valve 52, the first fetch valve 61, the second fetch valve 62, the first pump 71, The second pump 72, the first relief valve 81, the second relief valve 82, and the through hole 9. detailed description

The core of the invention is to provide a structurally optimized hydraulically controlled double-plunger water pump, comprising two plunger groups consisting of a water cylinder and a cylinder, the cylinder piston of each plunger group being synchronously displaced with the cylinder piston, and each The water inlets of the cylinders of the water cylinders are respectively provided with a water inlet check valve which is single-passed from the outside to the inner cavity of the cylinder cylinder, and a water outlet check valve which is single-passed from the cylinder inner chamber to the external water outlet; two of the oil cylinders It is configured to alternately expand and contract under the control of the control valve. Compared with the prior art, the invention can reliably improve the output pressure and flow rate of the water pump, thereby meeting the demand for fire extinguishing of super high-rise buildings.

Without loss of generality, the present embodiment will be specifically described below with reference to the drawings of the specification.

Referring to FIG. 1, the overall structure diagram of the plunger water pump of the present embodiment is shown. The first plunger group 1 is composed of a first water cylinder 11 and a first cylinder 12, and the second plunger group 2 is composed of a second water cylinder 21 and a second cylinder 22. As shown, the projecting ends of the cylinder rods of the two cylinders are connected to the corresponding cylinder pistons to achieve simultaneous displacement of the cylinder piston and the cylinder piston of each plunger group. As for the overall arrangement, the water tank and the oil cylinder can be arranged coaxially as shown in the figure, or can be arranged substantially in parallel. Obviously, the structure of the coaxial arrangement is relatively simple, and the energy transmission efficiency is the best, so it is the optimal solution. .

A first water inlet check valve 13 is disposed in communication with the nozzle of the first cylinder cylinder 111 to realize a single conduction from the outside to the cylinder chamber; and at the same time, a nozzle is connected to the nozzle of the first cylinder cylinder 111. The first water outlet check valve 14 is unidirectionally guided from the cylinder bore to the external water outlet. Similarly, a second water inlet check valve 23 is disposed in communication with the nozzle of the second cylinder cylinder 211 to achieve a single conduction from the outside to the cylinder bore; and at the same time, communicate with the nozzle of the second cylinder cylinder 211 A second outlet check valve 24 is provided to achieve a single conduction from the cylinder bore to the external outlet. Since the two cylinders are configured to alternately expand and contract under the control of the control valve, the two cylinder pistons are alternately telescoped under the driving of the two cylinder pistons. Specifically, the external water outlet is located at the end of the outlet pipe 4 that communicates with the two outlet check valves for communication with the water line.

The specific operation process is: controlling the rodless cavity of the first cylinder 12 to enter the oil, and returning the oil to the rod cavity, and at the same time, the second oil rainbow 22 has the rod cavity oil inlet and the rodless cavity oil return; in this state, the first advance The water check valve 13 is non-conducting, the first water outlet is unidirectionally wide 14 and the first water tank 11 is drained, the second water inlet check valve 23 is turned on, and the second water outlet is unidirectionally wide 24 non-conducting, second The water tank 21 absorbs water. Controlling the first cylinder 12 The rodless chamber returns to the oil, and the rod chamber enters the oil. At the same time, the second cylinder 22 has the rod chamber returning oil and the rodless chamber is fed into the oil; in this state, the first inlet check valve 13 is turned on and the first outlet water is turned on. The one-way valve 14 is non-conducting, the first water tank 11 absorbs water, the second water inlet is unidirectionally wide 23 non-conducting, the second water outlet is unidirectionally wide 24, and the second water tank 21 is drained. Since the actual sealing structure can be effectively prevented between the water cylinder piston and the cylinder cylinder, the internal leakage can be effectively prevented; therefore, the present invention can effectively increase the output flow rate and the water pressure on the basis of continuous intermittent water supply.

In addition, the water tank 3 can be fixedly connected to the water tank. As shown in the figure, both the first water tank 11 and the second water tank 21 are placed in the water tank 3, and the water cylinder cylinder and the cylinder cylinder are fixedly connected to the water tank 3 through a connecting flange. Obviously, as long as the nozzle is located below the water line of the water tank 3, the basic needs of water absorption can be met.

Further, in conjunction with FIG. 2, the figure is a schematic structural view of a cylinder cylinder of the present embodiment. A through hole 9 communicating with the water tank 3 is formed in a side wall of each of the cylinders (111, 211) of the outer end of the rod chamber having the rod chamber. It should be understood that the through holes 9 may be provided in plurality and uniformly distributed circumferentially along the cylinders (111, 211).

The through hole 9 can be used to balance the pressure generated by the volume change in the rod cylinder of the cylinder (111, 211) during the movement of the cylinder piston. When the cylinder piston advances in the cylinder, the cylinder piston has the rod side When the volume is increased, a vacuum is generated, and the external water enters through the through hole 9; conversely, when the cylinder piston retreats in the cylinder, the cylinder piston has a smaller volume on the rod side to generate a pressure, and water is pressed out from the through hole 9. . In addition, water can be introduced into and out of the through hole 9, thereby cooling the cylinder piston rod connected to the cylinder piston, which in turn can cool and dissipate the hydraulic oil.

In addition to the above-mentioned plunger pump, the solution also provides a hydraulic control system for the plunger pump, see Fig. 3, which is a schematic diagram of the plunger pump hydraulic control system.

The pressure oil circuit P and the return oil circuit T of the hydraulic control system may select a system pressure oil circuit and a return oil circuit, or may independently set a pressure oil required for the corresponding oil pump to supply the plunger water pump. Based on the functional requirements of the first cylinder 12 and the second cylinder 22, the control valve is configured to have two working positions: in the first working position, the pressure oil passage P and the rodless chamber of the first cylinder 12, the second cylinder 22 have The rod chamber is connected, and the return oil passage T communicates with the rod chamber of the first cylinder 12 and the rodless chamber of the second cylinder 22, thereby controlling the rodless chamber of the first cylinder 12 to enter the oil, and the rod chamber is returned to the oil, The rod chamber of the two cylinders 22 In the second working position, the pressure oil passage P communicates with the rod chamber of the first cylinder 12 and the rodless chamber of the second oil rainbow 22, and the return oil passage T and the first oil rainbow The rodless cavity of the second cylinder 22 and the rod cavity of the second cylinder 22 are connected to control the oil return of the rodless chamber of the first cylinder 12, the oil of the rod chamber, the oil return of the rod chamber of the second cylinder 22, and the cavity without the rod Into the oil.

It should be noted that the specific configuration of the above control valve may be a directional control valve, or may be configured as two directional control valves, that is, specifically: two chambers disposed in the first cylinder 12 and the pressure oil passage p and oil return A first pilot directional valve 51 between the oil passages T, and a second pilot directional valve 52 disposed between the two chambers of the second oil rainbow 22 and the pressure oil passage P and the return oil passage T. Obviously, the configuration of two directional control valves with each cylinder can further optimize system control performance.

Further, the cylinder of the first cylinder 12 is provided with a receiving oil port communicating with the inner cavity of the cylinder barrel

121. The distance W between the receiving oil port 121 and the end of the rodless cavity is greater than the length L of the first cylinder piston 122. Similarly, the cylinder of the second cylinder 22 is provided with a receiving port connected to the inner cavity of the cylinder. 221. The distance between the receiving oil port 221 and the end of the rodless cavity is greater than the length of the second cylinder piston 222. That is, when the piston extends to the end of the stroke, the pressure of the corresponding pinch port is the oil pressure that drives the piston to control the switching of the two directional valves between the two working positions. Specifically, as shown in FIG. 3, the receiving oil port 121 of the first oil rainbow 12 communicates with the right control oil port of the first hydraulic directional valve 51 and the left control oil port of the second hydraulic directional valve 52 to drive the first A hydraulic directional valve 51 and a second hydraulic directional valve 52 are respectively located at the first working position and the second working position, and the receiving oil port of the second oil rainbow 22 and the left control oil port of the first hydraulic directional valve 51 are The right control port of the second pilot directional valve 52 is in communication to drive the first pilot directional valve 51 and the second pilot directional valve 52 to be respectively located in the second working position and the first working position.

The solution further includes two take-off valves, the first take-off valve 61 is located between the first oil cylinder 12 and the hydraulic control directional control valve, and the second take-off valve 62 is located between the second oil rainbow 22 and the hydraulic control directional control valve. As shown in the figure, the oil inlet A of each fetching valve is connected with the fetching port of the corresponding oil cylinder, the pressure balance port B is connected with the port C of the corresponding oil rainbow, the oil port D and the corresponding hydraulic control The control port of the directional valve is connected. In this way, the working reliability of the hydraulic reverse commutation can be further improved; meanwhile, when the cylinder piston approaches the extended limit position, the pressure balance port B of the take-off valve is in communication with the return oil passage T, and the inlet port A of the take-off valve is The system pressure oil passage P is connected, therefore, the pressure oil without rod cavity The liquid can flow in one direction through the take-off valve to the rod cavity, thereby avoiding the impact of the protruding terminal and affecting the stability of the system operation.

Also, to avoid unnecessary rigid impact of the cylinder at the retracted limit position. In this solution, a buffer bypass of a single-way conduction along the retracting direction of the piston can be arranged at the bottom of the cylinders of the two cylinders. Specifically, as shown in the figure, the oil outlet E of the buffer bypass communicates with the inner cavity of the cylinder through the bottom of the cylinder, and the distance between the inlet port F of the buffer bypass and the bottom of the cylinder is greater than the length of the cylinder piston. The side wall of the cylinder is in communication with the inner cavity of the cylinder. Similarly, when the cylinder piston approaches the retracting limit position, the oil outlet E of the buffer bypass communicates with the return oil passage T, and the oil inlet port F of the buffer bypass communicates with the pressure oil passage P, so that there is The pressure oil in the rod cavity can flow through the one-way valve on the buffer bypass to the rodless chamber to avoid impact on the retracting end.

As mentioned before, the pressure oil circuit P can use separate oil pumps to provide pressure oil for the two cylinders to better meet the functional requirements of the plunger pump. As shown in the figure, the pressure oil that communicates with the first oil rainbow 12 via the first pilot directional valve 51 routes the first pump 71 to supply oil, and the pressure oil route that communicates with the second cylinder 22 via the second pilot directional valve 52 is routed. The second pump 72 supplies oil; and, between the liquid outlets of the two pumps and the return oil passage, an overflow valve (the first relief valve 81 and the second relief valve 82) is disposed to reliably maintain the two The oil supply pressure is at a constant state.

The overflow overflow (the first overflow width 81 and the second overflow width 82) is preferably an electronically controlled overflow overflow, as shown in the figure, when the control valve is not energized, the inlet port of the relief valve passes through the The control valve constitutes a drain passage, that is, the pressure oil discharged from the outlet of the pump is directly returned to the fuel tank. When the control valve is energized, the overflow overflows to a constant pressure overflow and safety protection. In actual design, the two overflowing pressures are selected in the same way, so that the two cylinders are in the same working environment, ensuring reliable switching between the two.

The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalents, and improvements made within the spirit and scope of the invention are intended to be included within the scope of the appended claims.

Claims

Rights request

A plunger pump comprising two plunger groups consisting of a water cylinder and a cylinder, wherein the cylinder piston of each plunger group is displaced synchronously with the cylinder piston, and with each cylinder cylinder The water inlets are respectively provided with a water inlet check valve which is single-passed from the outside to the cylinder inner cavity, and a water outlet check valve which is single-passed from the cylinder inner cavity to the outer water outlet; the two cylinders are arranged in the control valve Alternately stretch under the control.

The plunger water pump according to claim 1, further comprising a water tank, wherein the two water tanks are built in the water tank.

The plunger water pump according to claim 2, wherein a through hole communicating with the water tank is formed in a side wall of the cylinder bore of the outer end portion of the rod chamber.

The plunger water pump according to claim 2 or 3, wherein the external water outlet is located at an end of an outlet pipe that communicates with the two outlet water check valves.

A hydraulic control system for a plunger pump according to any one of claims 1 to 4, comprising a pressure oil passage and a return oil passage, said control valve being configured to have two working positions: a working position, the pressure oil passage is connected with the rodless chamber of the first cylinder and the rod chamber of the second cylinder, and the return oil passage is connected with the rod chamber of the first cylinder and the rodless chamber of the second cylinder; In the working position, the pressure oil passage communicates with the rod chamber of the first oil rainbow and the rodless chamber of the second oil rainbow, and the oil return passage communicates with the rodless chamber of the first cylinder and the rod chamber of the second cylinder.

The plunger pump hydraulic control system according to claim 5, wherein the control valve is specifically: a first liquid disposed between the two chambers of the first cylinder and the pressure oil passage and the return oil passage a directional valve, and a second pilot directional valve disposed between the two chambers of the second oil rainbow and the pressure oil passage and the return oil passage;

The two cylinders are respectively provided with a receiving oil port communicating with the inner cavity of the cylinder barrel, and the receiving oil port is located at a side wall of the cylinder tube at a distance from the end of the rodless cavity greater than the length of the cylinder piston; The first oil rainbow receiving oil port communicates with the first hydraulic directional valve and the second hydraulic directional valve control oil port to drive the first hydraulic directional valve and the second hydraulic directional valve respectively to be in the first working a second working position of the second oil rainbow and a control oil port of the first hydraulic directional valve and the second hydraulic directional valve to drive the first hydraulic directional valve and the second The hydraulic directional valves are respectively located at the second working position and the first working position.

7. The plunger pump hydraulic control system according to claim 6, further comprising two intake valves respectively disposed between the two cylinders and the corresponding hydraulic directional valve, the oil inlet of each of the retrieval valves It is connected with the corresponding oil port of the corresponding oil rainbow, the pressure balance oil port is connected with the oil port of the corresponding oil rainbow, and the oil outlet is connected with the control oil port of the corresponding hydraulic control directional valve.

The plunger pump hydraulic control system according to claim 7, wherein the bottoms of the cylinders of the two cylinders are provided with a buffer bypass that is unidirectionally guided in the retracting direction of the piston, and the buffer side The oil outlet of the road communicates with the inner cavity of the cylinder through the bottom of the cylinder bore, and the distance between the oil inlet of the buffer bypass and the bottom of the cylinder is greater than the side wall of the cylinder and the cylinder at the length of the cylinder piston The cavity is connected.

The plunger pump hydraulic control system according to claim 8, wherein the pressure oil connected to the first cylinder via the first pilot directional valve is routed to the first pump for supplying oil, and the second liquid is passed through The pressure oil connecting the directional valve and the second oil cylinder is routed to the second pump for oil supply; and an overflow valve is disposed between the liquid outlet of the two pumps and the return oil passage.

10. The plunger pump hydraulic control system according to claim 9, wherein the relief valve is specifically an electrically controlled relief valve.