A slow flow pressure regulating valve

Abstract

The present application belongs to the technical field of automatic control of factory, and particularly relates to a slow flow pressure regulating valve. The present application comprises a valve housing, a valve rod, a pressure relief channel, a slow flow plate and an electromagnetic plate. The right side of the cylindrical section of the valve housing is an inlet, and the left side is an outlet. A pressure relief channel is installed at the bottom of the cylindrical section. The valve rod is inserted into the interior of the cylindrical section from the top of the valve housing, and the interior of the valve housing is divided into an inlet cavity and an outlet cavity. The valve housing and the valve rod are sealed and fixed by a fluorine rubber gasket. The rod body of the valve rod in the interior of the cylindrical section is externally provided with a slow flow plate. A fluorine rubber gasket is arranged between the slow flow plate and the rod body. A spring is sleeved on the outer side of the upper end of the valve rod, and the bottom of the spring is fixed on the valve housing by welding. The valve rod and the spring are isolated by cast iron welding. The electromagnetic plate is installed on the top of the valve rod. The present application is used for smoothly controlling the pressure of the pipeline when online instrument is calibrated, and the main process pipeline is protected.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automatic control of factory, and particularly relates to a slow flow pressure regulating valve. BACKGROUND

[0002] A certain factory is a closed circulation production mode, and materials in the pipeline are in an absolute pressure environment. When online pipeline instrument calibration is carried out, operations such as cutting off the pressure pipeline, material flow, pressure adjustment, etc. are needed. However, at present, manual control valve opening adjustment, pipeline cutting off and other operations are mainly adopted, which causes unstable pipeline pressure control, material blockage and other problems. In order to reduce manual operation and further improve the stability of pressure control, a slow flow pressure regulating valve is designed and developed, which is used for stable control of pipeline pressure during online instrument calibration and protection of the main process pipeline. SUMMARY

[0003] The application solves the technical problem of providing a slow flow pressure regulating valve for stable control of pipeline pressure during online instrument calibration and protection of the main process pipeline.

[0004] The technical scheme adopted by the application is as follows:

[0005] A slow flow pressure regulating valve comprises a valve housing, a valve rod, a pressure relief channel, a slow flow plate and an electromagnetic plate. The right side of the cylindrical section of the valve housing is an inlet, and the left side is an outlet. A pressure relief channel is installed at the bottom of the cylindrical section. The valve rod is inserted into the inside of the cylindrical section from the top of the valve housing, and the inside of the valve housing is divided into an inlet cavity and an outlet cavity. The valve rod and the valve housing are sealed and fixed by a fluororubber gasket. The rod body of the valve rod inside the cylindrical section is provided with a slow flow plate. A fluororubber gasket is arranged between the slow flow plate and the rod body. A spring is sleeved on the outside of the upper end of the valve rod. The bottom of the spring is fixed on the valve housing by welding. The valve rod and the spring are isolated by cast iron welding. An electromagnetic plate is installed on the top of the valve rod.

[0006] An KF16 outlet valve is installed on the inlet by welding. An KF16 outlet valve is installed on the outlet by welding. The material of the KF16 outlet valve is 316L.

[0007] A pressure relief inlet switch is arranged near the inlet end of the pressure relief channel, and a pressure relief outlet switch is arranged near the outlet end.

[0008] A pressure regulator is penetrated from the top on the side close to the inlet of the valve housing. A slow flow cavity is formed between the pressure regulator and the valve rod. The top of the pressure regulator is connected with a motor outside the valve housing.

[0009] The valve housing upper cover is provided with a pressure transmitter pressure lead pipe, and the pressure transmitter pressure lead pipe is provided with a buffer flow cavity pressure transmitter, the buffer flow cavity pressure transmitter is communicated with the buffer flow cavity, the left upper corner and the right upper corner of the valve housing cylindrical section are respectively provided with a pressure transmitter pressure lead pipe, the pressure transmitter pressure lead pipe is provided with an outlet cavity pressure transmitter and an inlet cavity pressure transmitter, the outlet cavity pressure transmitter is communicated with the outlet cavity, and the inlet cavity pressure transmitter is communicated with the inlet cavity.

[0010] The buffer flow plate is provided with a buffer flow plate outlet and a buffer flow plate inlet, the lower end of the rod body is provided with an inclined buffer flow channel, the buffer flow plate inlet is located on one side of the inlet, the buffer flow plate outlet is located on one side of the outlet, the position of the buffer flow plate inlet is higher than that of the buffer flow plate outlet, and the inclined direction of the buffer flow channel is inclined from the direction of the buffer flow plate inlet to the direction of the buffer flow plate outlet.

[0011] An electromagnet is fixed on the electromagnetic plate and the spring in a welding mode; the electromagnetic plate, the spring and the valve rod are connected with the valve housing outside the electromagnetic plate and the spring in a clamping groove mode and can slide freely; when the electromagnet at the top is electrified, magnetism is obtained, the lower end electromagnetic plate, the valve rod and the spring are attracted to be close to each other and kept in a closed state, at this time, the buffer flow channel at the bottom of the valve rod is communicated with the buffer flow plate inlet and the buffer flow plate outlet, and the fluid in the valve is circulated.

[0012] The buffer flow channel is provided with a DN15 round hole at the bottom of the valve rod to ensure that the valve rod can be moved to the highest position and can be communicated with the buffer flow plate inlet and outlet positions and finally conduct the entire valve cavity.

[0013] The pressure regulator comprises a flow switch plate, a flow bottom plate, an adjusting shaft and a motor gear, the flow switch plate and the flow bottom plate are overlapped with the adjusting shaft as the center, the flow bottom plate is located on the left side, a cross-shaped adjusting shaft is fixed on the center part of the flow bottom plate in a welding mode and protrudes to the right side by a certain length, the center part of the flow switch plate is designed as a cross hollow part corresponding to the position of the adjusting shaft, so as to provide support when the flow switch plate and the flow bottom plate are overlapped with the adjusting shaft as the center and enable the flow switch plate to rotate 360° around the flow bottom plate, and the motor gear of the motor is tightly combined with the switch plate gears distributed on the edge of the flow switch plate.

[0014] When the motor rotates, the flow switch plate rotates around the adjusting shaft to make the four flow switches with different sizes on the flow switch plate coincide with the bottom plate pressure regulating holes on the right side of the flow bottom plate, so as to control the flow size through the flow switch plate and the flow bottom plate.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows:

[0016] (1) The slow flow pressure regulating valve provided by the application is provided with a slow flow plate and a pressure regulating plate inside the valve body, and the internal space of the valve body is divided into three independent cavities;

[0017] (2) The slow flow pressure regulating valve provided by the application is provided with an independent pressure transmitter in the three cavities inside the valve body, and is associated with the pressure regulating plate and the slow flow plate switch of the cavity;

[0018] (3) The slow flow pressure regulating valve provided by the application is provided with a discharge channel for passing large flow materials in abnormal conditions;

[0019] (4) The slow flow pressure regulating valve provided by the application is provided with a bottom plate pressure regulating hole, a flow bottom plate and a flow switch, and the size of the flow switch is controlled by rotating a gear driven by a motor to adjust the flow of materials;

[0020] (5) The slow flow pressure regulating valve provided by the application is provided with a stamping fluorine rubber gasket between the valve rod and the valve shell to ensure the sealing property. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a structural schematic diagram of the slow flow pressure regulating valve provided by the application;

[0022] Figure 2 The figure is a structural exploded view of the pressure regulator;

[0023] Figure 3 The figure is a front view of the pressure regulator

[0024] In the figure, 1 is a valve shell, 2 is an outlet, 3 is a pressure relief outlet switch, 4 is an outlet cavity pressure transmitter, 5 is a spring, 6 is a motor, 7 is a slow flow cavity pressure transmitter, 8 is an inlet cavity pressure transmitter, 9 is an inlet, 10 is a pressure relief channel, 11 is a pressure relief inlet switch, 12 is an electromagnet, 13 is a valve rod, 14 is a fluorine rubber gasket, 15 is a fluorine rubber gasket, 16 is a slow flow plate, 17 is a slow flow plate outlet, 18 is a slow flow channel, 19 is a slow flow plate inlet, 20 is a pressure regulator, 21 is an electromagnetic plate, 22 is an outlet cavity, 23 is a slow flow cavity, 24 is an inlet cavity, 25 is a flow switch plate, 26 is a flow bottom plate, 27 is an adjusting shaft, 28 is a fluorine rubber gasket, 29 is a bottom plate pressure regulating hole, 30 is a flow switch, 31 is a switch plate gear, and 32 is a motor gear. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the application.

[0026] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] As shown in Figure 1 The present application provides a slow flow pressure regulating valve, which comprises a valve housing 1, a valve stem 13, a pressure relief channel 10, a slow flow plate 16, an electromagnetic plate 21,

[0029] The valve housing 1 is mainly made of cast iron and is installed in a right-to-left manner. The right side of the cylindrical section of the valve housing 1 is the inlet 9, and the left side is the outlet 2. The outlet 2 and the inlet 9 are made of 316L and are welded to the left and right sides of the valve housing 1. The design adopts KF16 quick connection. The inlet 9 is installed with a KF16 outlet valve in a welding manner. The left side is the outlet 2. The outlet 2 is installed with a KF16 outlet valve in a welding manner. The material of the KF16 outlet valve is 316L. A DN20 pressure relief channel 10 made of 316L is installed at the bottom of the cylindrical section. The length of the channel is 20 cm. The pressure relief channel 10 is connected to the valve housing 1 in a welding manner. A pressure relief inlet switch 11 is arranged on the pressure relief channel 10 near the inlet 9, and a pressure relief outlet switch 3 is arranged near the outlet 2. The valve stem 13 is inserted into the inside of the cylindrical section from the top of the valve housing 1, dividing the inside of the valve housing 1 into an inlet cavity 24 and an outlet cavity 22. A pressure regulator 20 penetrates through the top of the valve housing 1 near the inlet 9. A slow flow cavity 23 is formed between the pressure regulator 20 and the valve stem 13. The top of the pressure regulator 20 is connected with a motor 6 outside the valve housing 1. The valve housing 1 and the valve stem 13 are sealed and fixed by a fluororubber gasket 14.

[0030] The valve housing 1 upper cover installs pressure transmitter pressure pipe, the pressure transmitter pressure pipe is equipped with the buffer flow cavity pressure transmitter 7, the buffer flow cavity pressure transmitter 7 is connected with buffer flow cavity 23, the valve housing 1 upper left corner and right corner of cylindrical section installs pressure transmitter pressure pipe respectively, the pressure transmitter pressure pipe is equipped with the outlet cavity pressure transmitter 4 and inlet cavity pressure transmitter 8 respectively, the outlet cavity pressure transmitter 4 is connected with outlet cavity 22, the inlet cavity pressure transmitter 8 is connected with inlet cavity 24;

[0031] The valve stem 13 is located in the cylindrical segment inside the rod body outside the buffer plate 16, the buffer plate 16 is equipped with fluorine rubber gasket 15 between the rod body, the buffer plate 16 is respectively opened buffer plate outlet 17 and buffer plate inlet 19, the lower end of the rod body, the inclined buffer flow channel 18 is opened, the buffer plate inlet 19 is located on one side of the inlet 9, the buffer plate outlet 17 is located on one side of the outlet 2, the position of the buffer plate inlet 19 is higher than the buffer plate outlet 17, the inclination direction of the buffer flow channel 18 is inclined from the direction of the buffer plate inlet 19 to the direction of the buffer plate outlet 17, and the position of the buffer plate outlet 17 is higher than the highest position of the buffer flow channel 18;

[0032] The valve stem 13 is provided with fluorine rubber gasket 14 at the top of the valve housing 1, which is used to ensure the sealing property; the spring 5 is sleeved on the upper end of the valve stem 13, and the bottom of the spring 5 is fixed on the valve housing 1 by welding; the valve stem 13 and the spring 5 are isolated by cast iron welding; the electromagnetic plate 21 is installed on the top of the valve stem 13. The top electromagnetic switch is composed of electromagnet 12, spring 5, valve stem 13, electromagnetic plate 21 and gasket. The electromagnetic plate 21 is fixed on the top of the valve stem 13 by welding. An electromagnet 12 is fixed on the top of the electromagnetic plate 21 and the spring 5 by welding; the electromagnetic plate 21 and the valve housing 1 outside the spring 5 are connected by a clamping groove, and the electromagnetic plate 21 can drive the spring 5 and the valve stem 13 to slide freely; when the electromagnet 12 at the top is electrified, the magnetic property is obtained, the lower end electromagnetic plate 21, valve stem 13 and spring 5 are attracted to approach and keep closed, at this time, the buffer flow channel 18 at the bottom of the valve stem 13 is communicated with the buffer plate 16 inlet and buffer plate outlet 17, and the fluid in the valve flows;

[0033] The buffer flow channel 18 is provided with a round hole with DN15 at the bottom of the valve stem 13 to ensure that the valve stem 13 can be connected with the inlet and outlet positions of the buffer plate 16 when it moves to the highest position, and finally the whole valve cavity is connected.

[0034] The buffer plate 16 is fixed in the valve inner housing by welding; the inlet of the buffer plate 16 is opened in the right side of the buffer plate 16, close to the position of one third of the top;

[0035] The slow flow plate outlet 17 is opened near the bottom 1 / 3 on the left side of the slow flow plate 16;

[0036] As shown in Figure 2 , 3 , the present application provides a pressure regulator structure, which is Figure 1 the pressure regulator 20. It includes the flow switch plate 25, the flow bottom plate 26, the adjusting shaft 27, the motor gear 32,

[0037] Figure 2 After the pressure regulator structure is disassembled, the flow switch plate 25 and the flow bottom plate 26 are overlapped and placed around the adjusting shaft 27. The flow bottom plate 26 is on the left side, and the center part is fixed with the cross-shaped adjusting shaft 27 by welding, which protrudes to the right side for a certain length. Further, the protruding part of the cross-shaped adjusting shaft on the right side can rotate 360°. On the other hand, the center part of the flow switch plate 25 is designed with a cross-shaped hollow to correspond to the position of the adjusting shaft 27, which provides support when the flow switch plate 25 and the flow bottom plate 26 are overlapped and placed around the adjusting shaft 27, and enables the flow switch plate 25 to rotate 360° around the flow bottom plate 26. Further, the motor 6 is arranged in the Figure 1 , and the motor gear closely matches the switch plate gear 31 distributed on the edge of the flow switch plate 25. When the motor rotates, it drives the flow switch plate 25 to make a circular motion around the adjusting shaft 27, so that the four flow switches 30 of different sizes on the flow switch plate 25 coincide with the bottom plate pressure regulating holes 29 on the right side of the flow bottom plate 26, achieving the purpose of controlling the flow size through the flow switch plate 25 and the flow bottom plate 26.

[0038] The flow bottom plate 26 is made of 316L material and is fixed on the inner cavity shell of the valve by welding, located in the Figure 1 right side of the slow flow cavity 23. In the middle of the flow bottom plate 26, an outward protruding cross-shaped adjusting shaft 27 is arranged by welding to fix the flow switch plate 25; a 20mm circular hole is opened on the right side of the flow bottom plate 26 to guide the flow; a layer of fluororubber gasket 28 is installed by stamping connection to cover the entire flow bottom plate 26, which is used to increase the sealing performance of the bottom plate pressure regulating holes 29 in the flow bottom plate 26 and the flow switches 30 in the flow switch plate 25.

[0039] The flow switch plate 25 is a disc made of 316L material, with a recessed cross-shaped design in the center to buckle the adjusting shaft 27 of the flow bottom plate 26; the flow switch plate 25 is provided with flow switches 30 around the periphery by opening holes, with hole diameters of 5mm, 10mm, 15mm and 20mm respectively; the switch plate gear 31 is arranged around the periphery of the flow switch plate 25, with a total step number of 1000 for one rotation;

[0040] The switch plate gear 31 in the flow switch plate 25 is connected with the motor gear 32 on the right side of the valve housing 1 by snap connection, the motor rotates to drive the flow switch plate 25 to rotate, so as to adjust the closed aperture of the flow switch plate 25 and the flow bottom plate 26, thereby adjusting the flow.

[0041] The working principle of the present application is as follows:

[0042] The valve body is made of cast iron, and the valve body is divided into three cavities, namely, an inlet cavity, a slow flow cavity and an outlet cavity, by a slow flow plate and a pressure regulator. The pressure regulator is composed of a flow bottom plate, a flow switch and a pressure regulating hole, and the flow through the pressure regulator is controlled by adjusting the on-off of the pressure regulating hole. The position of the valve rod is adjusted to connect the slow flow plate outlet, the inlet and the slow flow channel on the valve rod, so as to further adjust the flow. Pressure transmitters are arranged in the three cavities respectively for detecting the parameter control condition. A pressure relief channel is arranged at the bottom of the valve body for protective pressure relief when the parameter in the valve cavity is out of control, and an electromagnetic switch is arranged as the control switch thereof. An electromagnetic switch is arranged at the top of the valve rod, and the valve rod is driven to move upward when the electromagnetic switch is energized, thereby controlling the connection of the slow flow channel.

[0043] The valve flow direction is that the fluid flows out from the left side and flows in from the right side, one outlet 2 is arranged on the left side, and one inlet is arranged on the right side. The whole valve is sealed by a cast iron shell, and electromagnetic switches are arranged at the top of the valve, the left side of the bottom of the valve and the right side of the bottom of the valve respectively, wherein the size of the electromagnetic switch at the bottom is one half of that at the top. The electromagnetic switch at the top has the same structure as the two electromagnetic switches at the bottom, and only the size and position are different.

[0044] When the fluid enters from the right side of the valve, the pressure in the cavity is detected by the inlet cavity pressure transmitter 8, so as to determine the required pressure regulator 20 aperture. The amount of fluid entering the slow flow cavity 23 is adjusted by driving the gear to rotate by the stepping motor 6. The pressure difference before and after the slow flow plate 16 is detected and compared by the slow flow cavity 23 and the outlet cavity pressure transmitter 4, so as to determine whether the outlet cavity pressure needs to be adjusted. If the outlet cavity pressure needs to be adjusted, the electromagnetic switch power supply is disconnected, so that the slow flow plate 16 is in a cut-off state, and the outlet cavity pressure is stable. When the pressures in the inlet cavity 24, the slow flow cavity 23 and the outlet cavity are all abnormal, it is judged that the valve pressure control fails, and at this time, it is an abnormal working condition, and the pressure relief channel 10 needs to be opened for special treatment.

[0045] The pressure relief channel 10 is used to directly release the pressure in the inlet cavity 24 to the valve outlet cavity 22 when the pressure in the inlet cavity 24 is over-limit and cannot be relieved by the slow flow plate 16 and the pressure regulator 20. When it is detected that the pressure in the inlet cavity 24 is over-limit for a certain time, the pressure relief inlet switch 11 is first opened, and then the pressure relief outlet switch 3 is opened, so as to quickly reduce the pressure in the inlet cavity 24.

[0046] The electromagnetic switch, pressure relief inlet switch 11, pressure relief outlet switch 3, after being powered, according to electromagnetic principle, makes electromagnet 12 obtain magnetism, thereby attracting electromagnetic plate 21 to close, changing valve state. When powered off, electromagnet 12 loses magnetism, due to the lower connection spring 5 of electromagnetic plate 21, thereby separating electromagnet 12 and electromagnetic plate 21 by elastic force, changing valve rod 13 position.

[0047] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be carried out in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, it is to be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, and the scope of the present application is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. No reference signs in the claims shall be construed as limiting the scope of the claims to the identity of the features to which the reference signs are attached.

[0048] Furthermore, it should be understood that although the description herein is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description herein is made in this way only for the sake of clarity, and those skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments which can be understood by those skilled in the art.

Claims

1. A slow flow pressure regulating valve characterized by, The valve housing (1) includes a valve stem (13), a pressure relief channel (10), a flow buffer plate (16), and an electromagnetic plate (21). The right side of the cylindrical section of the valve housing (1) is the inlet (9), and the left side is the outlet (2). A pressure relief channel (10) is installed at the bottom of the cylindrical section. The valve stem (13) is inserted into the interior of the cylindrical section from the top of the valve housing (1), dividing the interior of the valve housing (1) into an inlet chamber (24) and an outlet chamber (22). The valve stem (13) is sealed and fixed between the valve housing (1) and the valve stem (13) with a fluororubber gasket (14). The rod body of the valve stem (13) inside the cylindrical section is provided with a flow buffer plate (16). A fluororubber gasket (15) is provided between the flow buffer plate (16) and the rod body. A spring (5) is sleeved on the outside of the upper end of the valve stem (13). The spring (5) is fixed at the bottom of the valve housing (1) by welding. The valve stem (13) and the spring (5) are isolated by cast iron welding. An electromagnetic plate (21) is installed at the top of the valve stem (13). The flow buffer plate (16) has a flow buffer plate outlet (17) and a flow buffer plate inlet (19). The lower end of the rod body has an inclined flow buffer channel (18). The flow buffer plate inlet (19) is located on one side of the inlet (9), and the flow buffer plate outlet (17) is located on one side of the outlet (2). The position of the flow buffer plate inlet (19) is higher than that of the flow buffer plate outlet (17). The inclination direction of the flow buffer channel (18) is from the flow buffer plate inlet (19) to the flow buffer plate outlet (17), and the position of the flow buffer plate outlet (17) is higher than the highest position of the flow buffer channel (18).

2. The low-flow pressure regulating valve of claim 1, wherein A KF16 outlet valve is installed on the inlet (9) by welding. A KF16 outlet valve is installed on the outlet (2) by welding. The material of the KF16 outlet valve is 316L.

3. The low-flow pressure regulating valve of claim 1, wherein, A pressure relief inlet switch (11) is provided on the pressure relief channel (10) near the inlet (9), and a pressure relief outlet switch (3) is provided near the outlet (2).

4. The low-flow pressure regulating valve of claim 1, wherein, A pressure regulator (20) penetrates through the top of the valve housing (1) on the side near the inlet (9). The pressure regulator (20) forms a flow buffer chamber (23) with the valve stem (13). The top of the pressure regulator (20) is connected with a motor (6) located outside the valve housing (1).

5. The low-flow pressure regulating valve of claim 4, wherein, A pressure transmitter pressure lead pipe is installed on the upper cover of the valve housing (1). A flow buffer chamber pressure transmitter (7) is provided in the pressure transmitter pressure lead pipe. The flow buffer chamber pressure transmitter (7) communicates with the flow buffer chamber (23). Pressure transmitter pressure lead pipes are installed at the upper left and right corners of the cylindrical section of the valve housing (1). An outlet chamber pressure transmitter (4) and an inlet chamber pressure transmitter (8) are respectively provided in the pressure transmitter pressure lead pipes. The outlet chamber pressure transmitter (4) communicates with the outlet chamber (22), and the inlet chamber pressure transmitter (8) communicates with the inlet chamber (24).

6. The low-flow pressure regulating valve of claim 1, wherein, On the electromagnetic plate (21) and spring (5), a solenoid (12) is fixed by welding; the electromagnetic plate (21) and spring (5) are connected with the valve housing (1) outside by clamping groove, the electromagnetic plate (21) drives the spring (5) and valve stem (13) to slide freely; when the solenoid (12) at the top is energized, magnetism is obtained, attracting the lower end electromagnetic plate (21), valve stem (13) and spring (5) to move close together and keep closed, at this time, the bottom slow flow passage (18) of the valve stem (13) is communicated with the inlet and outlet of the slow flow plate (16), and the fluid in the valve is circulated.

7. The low-flow pressure regulating valve of claim 6, wherein, The slow flow passage (18) is provided with a DN15 round hole at the bottom of the valve stem (13) to ensure that the valve stem (13) moves to the highest position, and the slow flow plate (16) inlet and outlet positions are communicated, and finally the entire valve cavity is conducted.

8. The low-flow pressure regulating valve of claim 4, wherein, The pressure regulator (20) comprises a flow switch plate (25), a flow bottom plate (26), an adjusting shaft (27) and a motor gear (32), the flow switch plate (25) and the flow bottom plate (26) are overlapped with the adjusting shaft (27) as the center, wherein the flow bottom plate (26) is located on the left side, and a cross-shaped adjusting shaft (27) is fixed on the center part by welding, and protrudes to the right side by a certain length; the center part of the flow switch plate (25) is designed as a cross hollow to correspond to the position of the adjusting shaft (27), so as to provide support when the flow switch plate (25) and the flow bottom plate (26) are overlapped with the adjusting shaft (27) as the center, and make the flow switch plate (25) have the ability of 360° rotation around the flow bottom plate (26); the motor gear of the motor (6) is closely combined with the switch plate gear (31) distributed on the edge of the flow switch plate (25).

9. The low-flow pressure regulating valve of claim 4, wherein, When the motor rotates, the flow switch plate (25) is driven to make circular motion around the adjusting shaft (27), so that the four flow switches (30) of different sizes on the flow switch plate (25) coincide with the bottom plate pressure regulating hole (29) on the right side of the flow bottom plate (26), and the purpose of controlling the flow size through the flow switch plate (25) and the flow bottom plate (26) is achieved.

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