A back pressure valve for a minimum flow protection valve

Abstract

The utility model relates to valve technical field discloses a back pressure valve for minimum flow protection valve, including valve body, the valve body is equipped with from left to right in proper order valve seat, valve core, spring, valve bush, limiting nut, the valve bush is located the valve core outside, and the valve core plays the direction, spacing effect, the valve bush with valve body passes through the thread connection, and the spring pre -tightening force can be adjusted through the change valve bush installation position, changes the sealing force of valve core to valve seat, to adjust the preset back pressure size of back pressure valve. Through the limiting nut is limited to the valve bush, prevents the valve bush loosening in the use process. The utility model provides a back pressure valve for pump minimum flow protection valve, simple structure, and the maintenance is convenient, and the back pressure size can be adjusted, prevents the pressure in pipeline from reducing to below the preset pressure value, can effectively adapt minimum flow protection valve, avoids the cavitation and the flash evaporation in pipeline.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, specifically to a back pressure valve for a minimum flow protection valve. Background Technology

[0002] The bypass outlet of the minimum flow protection valve often experiences excessively low pressure, leading to cavitation and flashing in the bypass pipeline. This causes valve instability, erosion damage to the bypass system and pipelines, and generates vibration and noise. A back pressure valve, installed on the bypass pipeline, maintains the static pressure above a preset minimum value without affecting the flow rate. That is, the pressure will not drop below the given minimum value throughout the entire operating range, thus preventing cavitation and partial vaporization in the pipeline. Currently, most back pressure valves in China are diaphragm-type. Diaphragm-type back pressure valves are not sensitive enough to changes in flow rate. When the system flow rate fluctuates significantly, the diaphragm's action is delayed, failing to adjust the valve opening in time to maintain pressure stability. Furthermore, diaphragm-type back pressure valves are inconvenient to maintain; when the diaphragm is damaged and needs replacement, it often requires disassembling numerous parts, making the operation cumbersome and time-consuming. Summary of the Invention

[0003] In view of the above situation and to overcome the defects of the prior art, the purpose of this utility model is to provide a back pressure valve for a minimum flow protection valve. It has a simple structure, is easy to maintain, and can respond in a timely manner to maintain pipeline pressure stability. It can be well adapted to the minimum flow protection valve and avoid cavitation and flashing in the bypass pipeline of the minimum flow protection valve.

[0004] To achieve the above objectives, this utility model provides the following solution:

[0005] A back pressure valve for minimum flow protection valve, characterized in that: the back pressure valve for minimum flow protection valve includes a valve body, and the valve body is provided with a valve seat, a valve core, a spring, a valve sleeve, and a limit nut from left to right.

[0006] Furthermore, the valve sleeve is located outside the valve core and serves to guide and limit the valve core. The valve sleeve is connected to the valve body by a thread. By changing the installation position of the valve sleeve, the spring preload can be adjusted, the valve opening pressure can be changed, and thus the preset back pressure of the back pressure valve can be adjusted.

[0007] Furthermore, the valve core is located after the valve seat and inside the valve body cavity. The front end face of the valve core is provided with a valve core sealing surface, which can contact the valve seat sealing surface provided on the valve seat to form a seal. The rear end of the valve core is inserted into the valve sleeve, and the valve core can move left and right along the valve sleeve. By opening and closing with the valve seat, the valve flow rate is controlled, thereby controlling the pressure release and maintaining the pipeline pressure not lower than the preset value.

[0008] Furthermore, the spring is a cylindrical helical spring, which is disposed between the valve core and the valve sleeve to preset the initial value of the back pressure. When the pipeline pressure changes, the spring force interacts with the pipeline pressure to drive the valve core to move, thereby achieving dynamic adjustment of the flow rate and back pressure, and thus maintaining the minimum pressure in the pipeline.

[0009] Furthermore, the limiting nut is threadedly connected to the valve body to limit the valve sleeve and prevent it from loosening during use.

[0010] Compared with the prior art, the beneficial effects of this utility model are:

[0011] This utility model provides a back pressure valve for a minimum flow protection valve. It features a simple structure, is easy to maintain and replace, and utilizes a valve sleeve structure to adjust the back pressure. A limit nut restricts the valve sleeve's position, preventing it from loosening during use. It effectively prevents pipeline pressure from dropping below a preset value and is compatible with minimum flow protection valves, thus avoiding cavitation and flashing in the pipeline. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Explanation of reference numerals in the attached drawings: 1—valve body, 2—valve seat, 3—valve core, 4—spring, 5—valve sleeve, 6—limit nut, 7—inlet, 8—outlet Detailed Implementation

[0014] To make the technical means, creative features, working mechanism, and achieved purpose and effect of this utility model easy to understand, the technical solution and basic working principle of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model.

[0015] This utility model provides a back pressure valve for a minimum flow protection valve, such as... Figure 1 As shown, the valve body 1 includes a valve seat 2, a valve core 3, a spring 4, a valve sleeve 5, and a limit nut 7 arranged sequentially from left to right inside the valve body 1.

[0016] The valve sleeve 5 is sleeved on the outside of the valve core 3, and plays a guiding and limiting role for the valve core. The valve sleeve 5 is connected to the valve body 1 by threads. By changing the installation position of the valve sleeve 5, the preload of the spring 4 can be adjusted, the valve opening pressure can be changed, and thus the preset back pressure can be adjusted.

[0017] The valve core 3 is located behind the valve seat 2 and inside the cavity of the valve body 1. The front end face of the valve core 3 is provided with a valve core sealing surface, which can contact the valve seat sealing surface provided on the valve seat 2 to form a seal. The rear end of the valve core 3 is inserted into the valve sleeve 5, and the valve core 3 can move left and right along the valve sleeve 5. By opening and closing with the valve seat 2, the valve flow rate is controlled, thereby controlling the pressure release and maintaining the pipeline pressure not lower than the preset value.

[0018] A spring 4 is provided between the valve core 3 and the valve sleeve 5 to preset the initial back pressure value. When the pipeline pressure changes, the spring force interacts with the pipeline pressure to drive the valve core to move, thereby achieving dynamic adjustment of flow rate and back pressure, and thus maintaining the minimum pressure in the pipeline.

[0019] The limiting nut 6 is threadedly connected to the valve body 1 and is used to limit the valve sleeve 5 to prevent the valve sleeve from loosening during use.

[0020] The specific working principle of this utility model is as follows:

[0021] The working principle of the back pressure valve for minimum flow protection is mainly based on the interaction between spring force and fluid pressure to maintain the minimum pressure in the pipeline and prevent cavitation and flashing in the bypass pipeline of the minimum flow protection valve.

[0022] By adjusting the horizontal position of the valve sleeve 5, the internal spring 4 can be compressed or released, thereby setting the initial back pressure value. When the medium pressure at the inlet 7 is lower than the set back pressure value, the valve core 3 and the valve seat 2 form a seal, preventing fluid from passing through. When the medium pressure at the inlet 7 reaches or exceeds the set back pressure value, the medium pressure overcomes the spring force, the valve core 3 moves along the valve sleeve 5 towards the outlet 8, the valve opens, and the fluid begins to flow towards the outlet 8. Since the valve only opens when the pressure is sufficient, the pressure at the inlet end is maintained near the set value, thus ensuring that the pressure in the bypass line of the minimum flow protection valve does not drop below the preset value.

[0023] Based on this structure, various modifications and improvements can be made. These innovative variations based on this structure also fall within the protection scope of this utility model.

[0024] The above are merely preferred embodiments of this utility model. It should be noted that the above preferred embodiments should not be considered as limitations on this utility model, and the scope of protection of this utility model should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A back pressure valve for a minimum flow protection valve, characterized in that: The minimum flow protection valve uses a back pressure valve, which includes a valve body. From left to right, the valve body is provided with a valve seat, a valve core, a spring, a valve sleeve, and a limit nut.

2. The back pressure valve for the minimum flow protection valve according to claim 1, characterized in that: The valve sleeve is located outside the valve core and serves to guide and limit the valve core. The valve sleeve is connected to the valve body by a thread. By changing the installation position of the valve sleeve, the spring preload can be adjusted, the valve opening pressure can be changed, and thus the preset back pressure of the back pressure valve can be adjusted.

3. The back pressure valve for the minimum flow protection valve according to claim 1, characterized in that: The valve core is located behind the valve seat and inside the valve body cavity. The front end face of the valve core is provided with a valve core sealing surface, which can contact the valve seat sealing surface provided on the valve seat to form a seal. The rear end of the valve core is inserted into the valve sleeve, and the valve core can move left and right along the valve sleeve. By opening and closing with the valve seat, the valve flow rate is controlled, thereby controlling the pressure release and maintaining the pipeline pressure not lower than the preset value.

4. The back pressure valve for the minimum flow protection valve according to claim 1, characterized in that: The spring is a cylindrical helical spring, which is placed between the valve core and the valve sleeve to preset the initial back pressure value.

5. The back pressure valve for the minimum flow protection valve according to claim 1, characterized in that: The limiting nut is threadedly connected to the valve body and is used to limit the valve sleeve to prevent it from loosening during use.

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