Control valve for liquid-driven three-cylinder reciprocating pump

Abstract

The present application relates to the field of hydraulic three-cylinder reciprocating pump, disclose a kind of control valve for hydraulic three-cylinder reciprocating pump, control valve mainly includes valve core, valve sleeve, valve body, end cover and adjusting cover, certain regular valve port is opened on valve core, certain regular groove is opened on valve sleeve, valve core is constantly rotating at uniform speed in valve body, three groups of valve port with phase difference 120 ° are used to periodically supply oil to three oil cylinders, control three oil cylinders to move according to the law of " uniform acceleration-uniform speed-uniform deceleration", realize the instantaneous flow of hydraulic three-cylinder reciprocating pump theory without pulsation.

Description

Technical Field

[0001] This invention relates to the field of hydraulic three-cylinder reciprocating pumps, and more specifically to a control valve for a hydraulically driven three-cylinder reciprocating pump. Background Technology

[0002] Currently, reciprocating pumps on the market mainly use a crankshaft crosshead structure. Their stroke is limited by the crankshaft size and is generally small. To achieve a large output flow rate, the reciprocating frequency is relatively high, leading to rapid failure of the hydraulic end inlet and outlet check valves and significant vibration in the pump pipeline. The high reciprocating frequency also results in poor suction performance, making it unsuitable for transporting high-viscosity media. The motion characteristics of the crank-slider structure determine that the instantaneous flow rate is pulsating. This flow pulsation limits its application in conditions where flow pulsation is critical and also causes significant vibration in the pump pipeline. Currently, the most common hydraulically driven reciprocating pumps on the market are two-cylinder pumps, but three-cylinder and five-cylinder pumps are also available, mainly used for transporting concrete, pastes, etc. In one case, the pistons of the cylinders move back and forth, and when switching between suction and discharge in multiple cylinders, the instantaneous flow rate is very small, resulting in large flow pulsation. In another case, the cylinders only have a discharge stroke in one direction of motion, resulting in a large structural size for achieving the same flow output. Summary of the Invention

[0003] The present invention aims to provide a control valve for a hydraulically driven three-cylinder reciprocating pump to solve the problems of small instantaneous flow and large flow pulsation in the prior art when the hydraulic three-cylinder reciprocating pump switches between multiple cylinders for suction and discharge.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a control valve for a hydraulically driven three-cylinder reciprocating pump, comprising a cylindrical valve body, a valve sleeve, and a shaft-shaped valve core, wherein the valve sleeve is fixed in the valve body and the valve core is rotatably connected in the valve sleeve;

[0005] The valve body has a valve body oil inlet hole in the middle of the radial direction. Six annular grooves are symmetrically distributed on the inner wall of the valve body with the axis of the valve body oil inlet hole as the center. Each annular groove has a valve body oil outlet hole that communicates with the outside of the valve body. The six valve body oil outlet holes are symmetrically distributed with the axis of the valve body oil inlet hole as the center. This can help reduce the overall size of the valve body.

[0006] The valve sleeve has a valve sleeve oil inlet hole in the middle of the radial direction. The valve sleeve oil inlet hole is coaxial with the valve body oil inlet hole. Six sets of valve sleeve oil outlet holes are symmetrically distributed on the valve sleeve with the axis of the valve sleeve oil inlet hole as the center. Each set of valve sleeve oil outlet holes corresponds to a groove on the valve body. The phase difference between two adjacent sets of valve sleeve oil outlet holes on one side of the valve sleeve oil inlet hole is 90°. Each set of valve sleeve oil outlet holes includes two holes symmetrically distributed with the valve sleeve axis.

[0007] The valve core has an axial oil passage inside. The outer wall of the middle part of the valve core has an oil inlet ring groove that communicates with the oil inlet hole of the valve sleeve. The oil inlet ring groove has a valve core oil inlet hole that communicates with the oil passage. Six sets of valve core oil outlet holes are symmetrically distributed on the valve core with the axis of the valve core oil inlet hole as the center. Each set of valve core oil outlet holes corresponds to a set of valve sleeve oil outlet holes on the valve sleeve that are intermittently connected. The phase difference between two adjacent sets of valve core oil outlet holes on one side of the valve core oil inlet hole is 30°. Each set of valve core oil outlet holes includes two holes that are symmetrically distributed with the valve core axis.

[0008] The valve body has sealing structures at both ends, and the valve core has axial anti-channeling structures at both ends.

[0009] Preferably, as an improvement, the phase difference between adjacent valve body outlet holes on one side of the valve body inlet hole is 90°.

[0010] Preferably, as an improvement, the oil outlet hole of the valve sleeve is a square hole.

[0011] Preferably, as an improvement, the oil outlet of the valve core is a square hole.

[0012] Preferably, as an improvement, the valve sleeve and valve body are interference fit.

[0013] Preferably, as an improvement, the valve core includes a valve core body and a valve core cover. The valve core body has a long blind hole as an oil passage, and the valve core cover is fixedly connected to the end of the valve core body to seal the long blind hole.

[0014] Preferably, as an improvement, multiple oil inlet holes are evenly arranged along the circumference of the valve core. This reduces the unbalanced radial force generated in the valve core when high-pressure oil enters.

[0015] Preferably, as an improvement, the sealing structure includes annular cover plates connected to both ends of the valve body. The annular cover plates are pressed against the outer side of the end faces of the valve body and valve sleeve, and sealing rings are provided on both sides of the interface between the valve body and valve sleeve. The annular cover plates also serve to press and prevent the valve sleeve from rotating.

[0016] Preferably, as an improvement, the axial anti-migration structure includes an adjusting cover plate connected to the annular cover plate. The adjusting cover plate is sleeved on the valve core, and the valve core has shoulders at both ends. A thrust bearing sleeved on the valve core is provided between the shoulders and the adjusting cover plate. The adjusting cover plate is also provided with sealing rings to seal between the adjusting cover plate and the annular cover plate, and between the adjusting cover plate and the valve core. The thrust bearing can limit the axial movement of the valve core during rotation, and the adjusting cover plate can adjust the tightness of the thrust bearing.

[0017] The present invention also provides a hydraulically driven three-cylinder reciprocating pump, which uses the above-mentioned control valve as the oil circuit control component for the three cylinders. The oil inlet of the control valve body is connected to the oil pump outlet, and every two symmetrically distributed oil outlets of the valve body are connected to the left and right oil ports of one cylinder respectively. The valve core is connected to a drive device that can drive it to rotate.

[0018] The principle of this invention is as follows: In practical application, the drive device is connected to the valve core, driving the valve core to rotate at a uniform speed. The oil inlet of the valve body is connected to the oil pump. The high-pressure oil output by the oil pump enters the control valve through the oil inlet of the valve body and reaches the oil passage inside the valve core. Six square oil outlet holes are opened in the axial direction of the valve core, and six square oil outlet holes are opened in the axial direction of the valve sleeve. As the valve core rotates continuously, the valve opening formed by the oil outlet holes of the valve core and the oil outlet holes of the valve sleeve periodically opens and closes, controlling the hydraulic oil to flow out of the valve sleeve, and then out of the oil outlet holes of the valve body after passing through the annular groove on the valve body. The valve body has two symmetrically distributed oil outlets connected to the left and right oil ports of one cylinder, respectively. For the three cylinders, the periodic opening and closing of the valve ports formed by the valve core and valve sleeve controls the cylinder pistons to perform periodic reciprocating motion according to a uniform acceleration-uniform speed-uniform deceleration pattern. The valve core and valve sleeve oil outlets are positioned so that the three cylinders are 120° out of phase, and the sum of the instantaneous velocities of the three cylinder pistons is a constant. The six oil ports of the three cylinders are simultaneously connected to six cartridge logic valves. When the control valve controls one oil port of a cylinder to be the inlet, all cartridge logic valve ports corresponding to the other oil port of the cylinder are opened, reducing the cylinder discharge port pressure, lowering the system's throttling losses, and improving system efficiency.

[0019] The advantages of this invention include:

[0020] 1. This control valve can control the three cylinders of the hydraulically driven three-cylinder reciprocating pump to move in accordance with the law of "uniform acceleration-uniform speed-uniform deceleration", so as to achieve the theoretical instantaneous flow rate of the hydraulically driven three-cylinder reciprocating pump without pulsation.

[0021] 2. The control valve has a high degree of integration and low cost. One control valve can perform the functions of six conventional proportional valves, and its size and cost are much smaller than six proportional valves.

[0022] 3. During the operation of the control valve, the total valve opening is a constant value. The control valve is equivalent to a flow distributor, and the oil supply of the system is a constant value. This can achieve no overflow flow loss and greatly improve the efficiency of the system.

[0023] 4. The valve core and valve sleeve are sealed by a gap without any sealing components. The sealing method is simple and reliable, which can prevent the sealing components from getting stuck in the gap between the valve core and valve sleeve and causing the control valve to jam.

[0024] 5. The symmetrical valve port design and the oil inlet ring groove of the valve core, as well as the multiple oil inlet holes opened along the axial direction at the oil inlet in the middle of the valve core, can reduce the unbalanced radial force of the valve core, prevent the control valve core from jamming, and reduce the driving torque of the valve core.

[0025] 6. During the rotation of the valve core, the valve opening gradually increases → remains unchanged → gradually decreases → closes. When the oil cylinder reverses direction, the valve opening changes slowly, resulting in minimal hydraulic shock. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the valve body in Embodiment 1 of the present invention.

[0028] Figure 3 This is a schematic diagram of the valve sleeve in Embodiment 1 of the present invention.

[0029] Figure 4 This is a schematic diagram of the valve core structure in Embodiment 1 of the present invention. Detailed Implementation

[0030] The following detailed description illustrates the specific implementation method:

[0031] The reference numerals in the accompanying drawings include: valve body 1, valve sleeve 2, valve core 3, annular cover plate 4, adjusting cover plate 5, thrust bearing 6, sealing ring 7, valve body oil outlet 101, valve body oil inlet 102, annular groove 103, valve sleeve oil inlet 201, valve sleeve oil outlet 202, valve core body 301, valve core cover 302, oil inlet annular groove 303, valve core oil inlet 304, and valve core oil outlet 305.

[0032] Example 1, basically as shown in the attached document. Figure 1 As shown: A control valve for a hydraulically driven three-cylinder reciprocating pump includes a cylindrical valve body 1, a valve sleeve 2, and a shaft-shaped valve core 3. The valve sleeve 2 is fixed inside the valve body 1 with an interference fit, and the valve core 3 is rotatably connected inside the valve sleeve 2. The valve core 3 and the valve sleeve 2 are fitted with a small clearance.

[0033] like Figure 2 As shown, a valve body oil inlet hole 102 is radially provided in the middle of the valve body 1. Six annular grooves 103 are symmetrically distributed on the inner wall of the valve body 1 with the axis of the valve body oil inlet hole 102 as the center. Each annular groove 103 is provided with a valve body oil outlet hole 101 that communicates with the outside of the valve body 1. The six valve body oil outlet holes 101 are symmetrically distributed with the axis of the valve body oil inlet hole 102 as the center. This can help reduce the overall size of the valve body 1. The phase difference between adjacent valve body oil outlet holes 101 on one side of the valve body oil inlet hole 102 is 90°.

[0034] like Figure 3As shown, a valve sleeve oil inlet hole 201 is radially opened in the middle of the valve sleeve 2. The valve sleeve oil inlet hole 201 is coaxially arranged with the valve body oil inlet hole 102. Six sets of valve sleeve oil outlet holes 202 are symmetrically distributed on the valve sleeve 2 with the axis of the valve sleeve oil inlet hole 201 as the center. Each set of valve sleeve oil outlet holes 202 corresponds to a ring groove 103 on the valve body 1. The phase difference between two adjacent sets of valve sleeve oil outlet holes 202 on one side of the valve sleeve oil inlet hole 201 is 90°. Each set of valve sleeve oil outlet holes 202 includes two square holes symmetrically distributed with the axis of the valve sleeve 2.

[0035] like Figure 4 As shown, the valve core 3 includes a valve core body 301 and a valve core cover 302. The valve core body 301 has an axially elongated blind hole as an oil passage. The end of the elongated blind hole has an internal thread. The valve core cover 302 is connected to the valve core body 301 through the internal thread and then welded to the valve core body 301 at the end to form the valve core 3. The outer wall of the middle part of the valve core 3 has an oil inlet annular groove 303 that communicates with the oil inlet hole 201 of the valve sleeve. Multiple valve core oil inlet holes 304 that communicate with the oil passage are evenly opened on the oil inlet annular groove 303 along the circumference of the valve core 3. This can reduce the unbalanced radial force generated in the valve core 3 when high-pressure oil enters. With the axis of the valve core oil inlet hole 304 as the center, six sets of valve core oil outlet holes 305 are symmetrically distributed on the valve core 3. Each set of valve core oil outlet holes 305 corresponds to a set of valve sleeve oil outlet holes 202 on the valve sleeve 2 that are intermittently connected. The phase difference between two adjacent sets of valve core oil outlet holes 305 on one side of the valve core oil inlet hole 304 is 30°. Each set of valve core oil outlet holes 305 includes two square holes symmetrically distributed with the axis of the valve core 3.

[0036] Annular cover plates 4 are bolted to both ends of the valve body 1. The annular cover plates 4 press against the outer end faces of the valve body 1 and valve sleeve 2. Sealing rings 7 are embedded in the annular cover plates 4 on both sides of the interface between the valve body 1 and valve sleeve 2. The annular cover plates 4 also serve to press and prevent rotation of the valve sleeve 2. Annular adjusting cover plates 5 are bolted to the annular cover plates 4. The adjusting cover plates 5 are fitted onto the valve core 3. The valve core 3 has shoulders at both ends, and a thrust bearing 6 is fitted onto the valve core 3 between the shoulders and the adjusting cover plates 5. The thrust bearing 6 restricts axial movement of the valve core 3 during rotation, and the adjusting cover plates can adjust the tightness of the thrust bearing 6. The adjusting cover plates 5 also have sealing rings 7 that seal between the adjusting cover plates 5 and the annular cover plates 4, and between the adjusting cover plates 5 and the valve core 3.

[0037] Example 2 describes a hydraulically driven three-cylinder reciprocating pump. It uses the control valve from Example 1 as the hydraulic circuit control component for the three cylinders. The valve body inlet 102 of the control valve is connected to the pump outlet. Each pair of symmetrically distributed valve body outlets 101 are connected to the left and right oil ports of one cylinder, respectively. The valve core 3 is connected to a drive device that can rotate it. The six oil ports of the three cylinders are simultaneously connected to six cartridge logic valves. When the control valve controls one oil port of a cylinder to be the inlet, all cartridge logic valve ports corresponding to the other oil port of the cylinder are fully opened.

[0038] The specific implementation process is as follows: The drive device is connected to the valve core 3, driving the valve core 3 to rotate at a constant speed. The valve body oil inlet 102 of the rotary valve is connected to the oil pump. The high-pressure oil output by the oil pump enters the control valve through the valve body oil inlet 102 and reaches the oil passage inside the valve core 3. The valve core 3 has six square valve core oil outlet holes 305 in the axial direction, and the valve sleeve 2 has six square valve sleeve oil outlet holes 202 in the axial direction. As the valve core 3 rotates continuously, the valve port formed by the valve core oil outlet holes 305 and the valve sleeve oil outlet holes 202 opens and closes periodically, controlling the hydraulic oil to flow out of the valve sleeve 2, and then flow out from the valve body oil outlet hole 101 after passing through the annular groove 103 on the valve body 1. The valve body 1 has two symmetrically distributed oil outlet holes 101 connected to the left and right oil ports of one cylinder, respectively. Corresponding to the three cylinders, the periodic opening and closing of the valve ports formed by the valve core oil outlet hole 305 and the valve sleeve oil outlet hole 202 controls the cylinder pistons to perform periodic reciprocating motion according to a uniform acceleration-uniform speed-uniform deceleration pattern. The valve core oil outlet hole 305 and the valve sleeve oil outlet hole 202 ensure that the three cylinders are 120° out of phase, and the sum of the instantaneous velocities of the three cylinder pistons is a constant value. The six oil ports of the three cylinders are simultaneously connected to six cartridge logic valves. When the control valve controls one oil port of a cylinder to be the inlet, all cartridge logic valve ports corresponding to the other oil port of the cylinder are opened, reducing the oil discharge port pressure of the cylinder, lowering the throttling loss of the system, and improving system efficiency.

[0039] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A control valve for a hydraulically driven three-cylinder reciprocating pump, characterized in that: It includes a cylindrical valve body, a valve sleeve, and a shaft-shaped valve core. The valve sleeve is fixed inside the valve body, and the valve core is rotatably connected inside the valve sleeve. The valve body has a valve body oil inlet hole in the middle of the radial direction. Six annular grooves are symmetrically distributed on the inner wall of the valve body with the axis of the valve body oil inlet hole as the center. Each annular groove has a valve body oil outlet hole that communicates with the outside of the valve body. The six valve body oil outlet holes are symmetrically distributed with the axis of the valve body oil inlet hole as the center. The valve sleeve has a valve sleeve oil inlet hole in the middle of the radial direction. The valve sleeve oil inlet hole is coaxial with the valve body oil inlet hole. Six sets of valve sleeve oil outlet holes are symmetrically distributed on the valve sleeve with the axis of the valve sleeve oil inlet hole as the center. Each set of valve sleeve oil outlet holes corresponds to a groove on the valve body. The phase difference between two adjacent sets of valve sleeve oil outlet holes on one side of the valve sleeve oil inlet hole is 90°. Each set of valve sleeve oil outlet holes includes two holes symmetrically distributed with the valve sleeve axis. The valve core has an axial oil passage inside. The outer wall of the middle part of the valve core has an oil inlet ring groove that communicates with the oil inlet hole of the valve sleeve. The oil inlet ring groove has a valve core oil inlet hole that communicates with the oil passage. Six sets of valve core oil outlet holes are symmetrically distributed on the valve core with the axis of the valve core oil inlet hole as the center. Each set of valve core oil outlet holes corresponds to a set of valve sleeve oil outlet holes on the valve sleeve that are intermittently connected. The phase difference between two adjacent sets of valve core oil outlet holes on one side of the valve core oil inlet hole is 30°. Each set of valve core oil outlet holes includes two holes that are symmetrically distributed with the valve core axis. The valve body has sealing structures at both ends, and the valve core has axial anti-channeling structures at both ends.

2. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The phase difference between adjacent valve body oil outlets on one side of the valve body oil inlet is 90°.

3. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The oil outlet hole of the valve sleeve is a square hole.

4. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The oil outlet hole of the valve core is a square hole.

5. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The valve sleeve and valve body are interference fit.

6. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The valve core includes a valve core body and a valve core cover. The valve core body has a long blind hole as an oil passage, and the valve core cover is fixedly connected to the end of the valve core body to seal the long blind hole.

7. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The valve core has multiple oil inlet holes evenly arranged along its circumference.

8. The control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 1, characterized in that: The sealing structure includes annular cover plates connected to both ends of the valve body. The annular cover plates are pressed against the outer side of the end faces of the valve body and valve sleeve. Sealing rings are provided on both sides of the interface between the valve body and valve sleeve on the annular cover plates.

9. A control valve for a hydraulically driven three-cylinder reciprocating pump according to claim 8, characterized in that: The axial anti-channeling structure includes an adjusting cover plate connected to an annular cover plate, the adjusting cover plate being sleeved on the valve core, the valve core having shoulders at both ends, a thrust bearing sleeved on the valve core being provided between the shoulders and the adjusting cover plate, and a sealing ring being provided on the adjusting cover plate to seal between the adjusting cover plate and the annular cover plate, and between the adjusting cover plate and the valve core.

10. A hydraulically driven three-cylinder reciprocating pump, characterized in that: The control valve for a hydraulically driven three-cylinder reciprocating pump as described in any one of claims 1-9 is used as the oil circuit control component for the three cylinders. The oil inlet of the valve body is connected to the oil pump outlet, and every two symmetrically distributed oil outlets of the valve body are connected to the left and right oil ports of one cylinder, respectively. The valve core is connected to a drive device that can drive it to rotate.

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