Minimum flow protection valve of pump

Abstract

The invention relates to the technical field of valves, and discloses a pump minimum flow protection valve which comprises a valve body, a valve cover, a bypass body, a valve element, a spring, a rear support, a guide ring and a front lining, a bypass opening communicated with the bypass body is formed in the side of the valve body, the bypass body is fixed to the valve body through a bolt, a control cover is arranged in the bypass opening, and the valve element is arranged in the control cover. A control head is arranged in the control cover, a transmission rod is connected between the control head and the valve element, the control head senses movement of the valve element through the transmission rod to achieve left-right movement, a throttling body and a sealing ring are arranged in the bypass body, and a backflow channel is formed in the combination of the throttling body, the control cover and the control head. A cascade piston is arranged in the backflow channel, a multi-stage pressure reduction sealing structure is arranged on the surface of the cascade piston, a multi-stage pressure reduction sealing face matched with the cascade piston is arranged in the throttling body, and left-right movement of the cascade piston can be controlled through left-right movement of the control head, so that whether a medium flows back or not and the backflow amount are controlled. The pump minimum flow protection valve provided by the invention is simple in structure, and the functions of non-return, backflow and pressure reduction can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to a minimum flow protection valve for a pump. Background Art

[0002] When the pump is running close to the minimum allowable flow range, the pump may experience overheating, cavitation damage, cavitation at the impeller inlet, vortex, backflow and other unstable flow problems. To avoid the above problems, it is necessary to replenish the fluid at the pump inlet by returning the fluid to ensure that the pump can operate normally at the minimum flow. There are generally traditional continuous circulation systems and controlled circulation systems for the protection of the minimum flow of the pump. Among them, the continuous circulation system has low cost and high operating costs, and the bypass flow value must be considered when selecting a pump; the bypass flow value can be ignored when selecting a pump for the controlled circulation system, but the system is complex, with many components, high cost, high maintenance cost, and there is a bypass opening delay phenomenon. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a pump minimum flow protection valve for realizing automatic protection of the minimum flow of the pump. The automatic circulation valve can automatically identify flow changes and integrate all functions of the control circulation system. It has a simple structure and low cost, but the design and processing and manufacturing are relatively difficult. The automatic circulation valve has the functions of check, flow sensing, recirculation control, and bypass multi-stage adjustable pressure reduction. When the main road is fully closed, the bypass is fully open; as the main road is opened, the bypass is gradually closed, and when the main road flow is greater than the minimum flow of the pump fully open, the bypass is fully closed. The minimum flow of the bypass fully open meets the minimum continuous operation requirements of the pump and can economically and effectively ensure the normal operation of the centrifugal pump system.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A pump minimum flow protection valve comprises a valve body, a valve cover, a bypass body and a valve core. A bypass port connected to the bypass body is provided on the side of the valve body. The bypass body is fixed to the valve body by bolts. A control cover is provided in the bypass port. A control head is provided in the control cover. An inlet is provided on the control head.

[0006] Furthermore, a front sleeve is provided in the valve body, a valve cover is provided at the upper end of the valve body, a rear support is provided in the valve cover, a guide ring is provided outside the rear support, the front end of the valve core cooperates with the guide ring, the rear end of the valve core cooperates with the front sleeve, a spring is provided between the valve core and the rear support and the guide ring, the valve core can move up and down along the guide ring, and a seal can be formed between the valve core and the valve body to realize the check function.

[0007] Furthermore, a throttle body and a sealing ring are provided in the bypass body, and a reflux channel is formed inside the throttle body, the control cover and the control head.

[0008] Furthermore, a cascade piston is provided in the reflux channel, and the cascade piston can move left and right in the reflux channel. A multi-stage pressure reducing sealing structure is provided on the surface of the cascade piston. A multi-stage pressure reducing sealing surface cooperating with the cascade piston is provided in the throttle body. A multi-stage adjustable sealing pressure reducing structure is formed between the cascade piston and the throttle body, which can reduce the pressure of the reflux medium.

[0009] Furthermore, a transmission rod is connected between the control head and the valve core. The control head senses the movement of the valve core through the transmission rod to achieve left and right movement. The left and right movement of the control head can control the left and right movement of the cascade piston, thereby controlling the area of ​​the medium reflux channel and achieving medium reflux.

[0010] The effects of the present invention are:

[0011] A pump minimum flow protection valve provided by the present invention can realize check, bypass reflux and pressure reducing functions. The valve core can automatically open and close in response to the medium flow to prevent the medium from flowing back and causing damage to the pump. The opening size of the bypass is automatically adjusted according to the size of the main flow. The reflux structure and the pressure reducing structure are integrated in the bypass body. The structure is simple and compact. Reflux is achieved when the bypass is opened, which can ensure the normal operation of the pump even at the minimum flow.

[0012] The invention provides a pump minimum flow protection valve, in which a multi-stage pressure reducing sealing structure is arranged on the surface of the cascade piston and the cascade piston liner, and a multi-stage adjustable sealing pressure reducing structure is formed between the cascade piston and the throttle body, thereby ensuring the pressure reducing effect while avoiding cavitation and noise. The cascade piston and the cascade piston liner are arranged in the bypass body, which is easy to disassemble and maintain, thereby reducing the equipment maintenance cost.

[0013] The present invention provides a pump minimum flow protection valve, which can transmit the sensed flow change to the control head through a transmission rod to move it left and right, thereby realizing the opening and closing adjustment of the bypass. When the pump is running at a low flow rate, the bypass is automatically opened to realize backflow. When the pump is operating normally, the bypass is automatically closed. It has a fully mechanical automatic structure and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention;

[0015] Explanation of reference numerals: 1—valve body, 2—valve core, 3—front bushing, 4—control cover, 5—transmission rod, 6—control head, 7—spring, 8—guide ring, 9—rear support, 10—valve cover, 11—bypass port, 12—bypass body, 13—throttling body, 14—sealing ring, 15—cascade piston, 16—return channel, 17—inlet DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, working mechanism, purpose and effect achieved by the present invention easy to understand, the technical scheme and working mechanism in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

[0017] like Figure 1 The pump minimum flow protection valve shown includes a valve body 1, a valve cover 10, a bypass body 12, and a valve core 2. A bypass port 11 connected to the bypass body 12 is provided on the side of the valve body 1. The bypass body 12 is fixed to the valve body 1 by bolts. A control cover 4 is provided in the bypass port 11. A control head 6 is provided in the control cover 4. An inlet 17 is provided on the control head 6.

[0018] Furthermore, a front bushing 3 is provided in the valve body 1, a valve cover 10 is provided at the upper end of the valve body 1, a rear support 9 is provided in the valve cover 10, a guide ring 8 is provided outside the rear support 9, the front end of the valve core 2 cooperates with the guide ring 8, the rear end of the valve core 2 cooperates with the front bushing 3, a spring 7 is provided between the valve core 2 and the rear support 9 and the guide ring 8, the valve core 2 can move up and down along the guide ring 8, and a seal can be formed between the valve core 2 and the valve body 1 to realize the check function.

[0019] Furthermore, a throttle body 13 and a sealing ring 14 are provided in the bypass body, and the throttle body 13 is combined with the control cover 4 and the control head 6 to form a reflux channel 16 therein.

[0020] Furthermore, a cascade piston 15 is provided in the reflux channel 16, and the cascade piston 15 can move left and right in the reflux channel 16. A multi-stage pressure reducing sealing structure is provided on the surface of the cascade piston 15. A multi-stage pressure reducing sealing surface cooperating with the cascade piston 15 is provided in the throttling body 13. A multi-stage adjustable sealing pressure reducing structure is formed between the cascade piston 15 and the throttling body 13, which can reduce the pressure of the reflux medium.

[0021] Furthermore, a transmission rod 5 is connected between the control head 6 and the valve core 2. The control head 6 senses the movement of the valve core 2 through the transmission rod 5 to achieve left and right movement. The left and right movement of the control head 6 can control the left and right movement of the cascade piston 15, thereby controlling whether the medium refluxes.

[0022] The following article focuses on the working mechanism of the pump minimum flow protection valve.

[0023] When the pump is started, the fluid enters the valve body 1 through the valve inlet, and the valve core 2 automatically senses the flow change. When the flow is at or below the minimum flow, the valve core 2 is sealed with the valve body 1, the main flow is not opened, the bypass is opened, and the medium flows to the reflux channel 16 through the inlet 17 on the control head 6. After multi-stage pressure reduction, the medium pressure is reduced step by step to a level that can flow back to the pump inlet, so that the pump will not overheat when running at the minimum flow rate, and cavitation and noise can be avoided.

[0024] When the inlet flow rate of the valve body 1 is greater than the set flow rate, the fluid enters the main flow path to lift the valve core 2, and the transfer rod 5 is lifted upward along with the operation of the valve core 2, pushing the control head 6 and the cascade piston 15 to move to the right until the cascade piston 15 and the sealing ring 14 form a seal to close the reflux channel 16, and the fluid no longer passes through the reflux channel 16, thereby ensuring the flow rate of the main flow path.

[0025] When fluid flows back from the outlet of the valve body 1, the valve core 2 automatically drops to close the main flow channel, realizing the check function, thereby preventing high-pressure water hammer from damaging the pump.

[0026] According to the above basic working principle, various modifications and improvements can be made on the basis of this structure. These innovative transformation structures based on this structure also fall within the protection scope of the present invention.

[0027] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A pump minimum flow protection valve, characterized in that: The pump minimum flow protection valve comprises a valve body, a valve cover, a bypass body and a valve core. A bypass port communicating with the bypass body is arranged on the side of the valve body. The bypass body is fixed to the inlet of the valve body by bolts.

2. A pump minimum flow protection valve according to claim 1, characterized in that The valve body is provided with a front bushing, the upper end of the valve body is provided with a valve cover, the valve cover is provided with a rear support, the outside of the rear support is provided with a guide ring, the front end of the valve core cooperates with the guide ring, the rear end of the valve core cooperates with the front bushing, a spring is provided between the valve core and the rear support and the guide ring, the valve core can move up and down along the guide ring, and a seal can be formed between the valve core and the valve body to realize the check function.

3. A pump minimum flow protection valve according to claim 1, characterized in that: A throttle body and a sealing ring are arranged in the bypass body, and a reflux channel is formed inside the throttle body, the control cover and the control head.

4. A pump minimum flow protection valve according to claim 3, characterized in that: A cascade piston is provided in the reflux channel. The cascade piston can move left and right in the reflux channel. A multi-stage pressure reducing sealing structure is provided on the surface of the cascade piston. A multi-stage pressure reducing sealing surface cooperating with the cascade piston is provided in the throttle body. A multi-stage adjustable sealing pressure reducing structure is formed between the cascade piston and the throttle body, which can reduce the pressure of the reflux medium.

5. A pump minimum flow protection valve according to any one of claims 1 to 4, characterized in that: A transmission rod is connected between the control head and the valve core. The control head senses the movement of the valve core through the transmission rod to achieve left and right movement. The left and right movement of the control head can control the left and right movement of the cascade piston, thereby controlling the area of ​​the medium reflux channel and achieving medium reflux.

Images