Diaphragm type steam pressure reducing valve

Abstract

The utility model discloses a diaphragm type steam pressure reducing valve, which solves the problems of low control precision, diaphragm damage and the like caused by the influence of upstream impact on a diaphragm. The control mechanism comprises a control diaphragm, a diaphragm tray and a control shell, the control shell is fixed below the main valve body, the lower end of the main valve rod penetrates through the control shell to be fixedly connected with the diaphragm tray, and the middle position of the control diaphragm is tightly attached to the diaphragm tray. The control diaphragm is installed in the control shell and divides an inner cavity of the control shell into an upper control cavity and a lower control cavity. The pilot valve is installed on the main valve body, an inlet of the pilot valve is communicated with the upstream valve cavity, and an outlet of the pilot valve, the downstream valve cavity and the control lower cavity are communicated with one another through guide pipes. Through the pre-adjusting effect of the pilot valve and the optimized control mechanism, the high control precision and stability can be kept under the complex working conditions such as frequent pressure fluctuation or large load change, and the common problems that in traditional design, pressure control is not stable, and a diaphragm is prone to being damaged are solved.

Description

Technical Field

[0001] The utility model relates to the field of pressure reducing valves, in particular to a diaphragm type steam pressure reducing valve. Background Art

[0002] A steam pressure reducing valve is a device specifically designed to reduce the pressure of steam from a higher value to a lower, safer or more suitable pressure for downstream equipment. In a diaphragm steam pressure reducing valve, the pressure of the high-pressure steam fluid is directly transmitted from the upstream position to the bottom of the diaphragm, forming a pressure difference. The diaphragm is a flexible element that deforms according to the change in the pressure difference. When the upstream pressure increases, the diaphragm is forced to move to adjust the opening of the valve disc, thereby achieving a pressure reduction effect. Traditional diaphragm steam pressure reducing valves often use a simple force balance mechanism, and the diaphragm directly senses the upstream pressure changes to achieve a rapid response to opening and closing. However, this design is difficult to achieve high-precision pressure control in the face of complex working conditions, such as frequent pressure fluctuations or large load changes. Especially when starting or the working conditions suddenly change, the upstream high-pressure steam directly impacts the diaphragm, which may cause excessive deformation or even damage to the diaphragm. Summary of the invention

[0003] Purpose of the utility model: In order to overcome the defects of the prior art, the utility model provides a diaphragm type steam pressure reducing valve to solve the problems of low control accuracy and diaphragm damage caused by upstream impact.

[0004] The technical solution of the utility model comprises a main valve and a pilot valve, the main valve comprises a main valve stem, a valve disc, a main spring and a main valve body, the main valve body is provided with an upstream valve cavity and a downstream valve cavity, the upper end of the main valve stem is fixedly connected to the valve disc, the main spring presses on the valve disc, a control mechanism is arranged below the main valve, the control mechanism comprises a control diaphragm, a diaphragm tray and a control housing, the control housing is fixed below the main valve body, the lower end of the main valve stem passes through the control housing and is fixedly connected to the diaphragm tray, the middle position of the control diaphragm is tightly fitted with the diaphragm tray, the control diaphragm is installed in the control housing and the inner cavity of the control housing is separated into a control upper cavity and a control lower cavity; the pilot valve is installed on the main valve body and the inlet of the pilot valve is connected to the upstream valve cavity, and the outlet of the pilot valve, the downstream valve cavity and the control lower cavity are connected to each other through a conduit.

[0005] With the above technical solution, the pilot valve first senses the pressure change in the upstream valve cavity, and changes the pressure in the control lower cavity by adjusting its own opening, thereby affecting the opening of the main valve, rather than directly acting on the control diaphragm. This can effectively buffer the impact of upstream high-pressure steam and reduce direct damage to the control diaphragm. The control diaphragm not only responds to the control adjustment from the pilot valve, but is also subject to the reverse force of the main spring, so that the control diaphragm can more accurately adjust the opening of the main valve and improve the accuracy of pressure control. At the same time, the main spring can also protect the diaphragm and prevent diaphragm damage caused by excessive pressure. Through the pre-adjustment effect of the pilot valve and the optimized control mechanism, it is possible to maintain high control accuracy and stability under complex working conditions, such as frequent pressure fluctuations or large load changes, thereby avoiding the common problems of unstable pressure control and easy diaphragm damage in traditional designs.

[0006] In a possible design, a pressure regulating mechanism for regulating the pilot valve is arranged above the main valve, and the pressure regulating mechanism includes a pressure regulating spring, an adjusting bolt and an adjusting bracket. The adjusting bracket is fixed above the pilot valve, and the two ends of the pressure regulating spring are respectively covered with a spring lower pad and a spring upper pad. The adjusting bolt is threadedly installed on the adjusting bracket and the lower end of the adjusting bolt presses on the spring upper pad; the spring lower pad is floatingly installed in the adjusting bracket and a closed regulating chamber is formed below the spring lower pad, and the regulating chamber is connected to the downstream valve chamber through a conduit; the pilot valve includes a floating opening and closing center rod, and the top end of the center rod is in contact with the spring lower pad.

[0007] With the above design, the top end of the center rod is in contact with the spring pad, and the closed regulating chamber formed under the spring pad is connected to the downstream valve chamber through a conduit. Any changes in the downstream pressure will be quickly fed back to the center rod, prompting the pilot valve to respond in time and adjust its opening, thereby accelerating the dynamic response speed of the entire system and improving the ability to cope with pressure fluctuations.

[0008] In a possible design, the pilot valve also includes a pilot valve seat, a valve ball, a bottom cover, a pilot valve body, an inner spring and a tower spring. The pilot valve body is installed between the adjusting bracket and the main valve body, the pilot valve seat is fixed on the pilot valve body, a flow channel is opened in the pilot valve seat, a center rod moves through the flow channel, the inner spring is sleeved on the center rod and the elastic force of the inner spring acts on the center rod; the bottom cover is fixed to the bottom of the pilot valve seat, the tower spring is installed in the bottom cover, and both ends of the tower spring are pressed on the bottom cover and the valve ball, the bottom end of the center rod is pressed against the valve ball, and the valve ball is floatingly arranged at the channel opening of the flow channel; the inlet of the pilot valve is opened on the bottom cover, the outlet of the pilot valve is located in the pilot valve body, and the flow channel is respectively connected to the inlet and outlet of the pilot valve.

[0009] With the above design, the position change of the center rod can accurately control the gap between the valve ball and the pilot valve seat, thereby adjusting the steam flow through the pilot valve and realizing precise regulation of the downstream pressure. Moreover, the inner spring is sleeved on the center rod, and its elastic force acts on the center rod, which enables the center rod to automatically adjust its position according to changes in the upstream pressure, ensuring that the opening of the pilot valve matches the current pressure level, and has a certain adaptive pressure regulation effect.

[0010] In a possible design, a limiting ridge protruding toward the control lower cavity is integrally provided in the control housing, and the limiting ridge abuts against the diaphragm tray to form a limit.

[0011] With the above design, when the valve disc is fully closed, the limiting ridge abuts against the diaphragm tray to prevent the diaphragm tray from moving further downward, thereby avoiding hard contact and excessive wear of the valve disc sealing surface, which helps to extend the service life.

[0012] In a possible design, the bottom surface of the spring lower pad is covered with a diaphragm, which isolates and closes the regulating chamber.

[0013] The above design enhances the sealing of the regulating chamber, ensuring that the pressure in the regulating chamber can be accurately transmitted to the spring pad or the center rod. Slight changes in downstream pressure can be transmitted more directly and quickly, thereby accelerating the response speed of the pilot valve and improving the sensitivity of the entire system to pressure changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the valve of the utility model being closed;

[0015] Figure 2 For this utility model Figure 1 A partial enlarged view of the middle A;

[0016] Figure 3 This is a schematic diagram of the structure of the valve opening of the utility model;

[0017] Among them, 1. main valve; 2. pilot valve; 11. main valve stem; 12. valve disc; 13. main spring; 14. main valve body; 141. upstream valve chamber; 142. downstream valve chamber; 3. control mechanism; 31. control diaphragm; 32. diaphragm tray; 33. control shell; 331. control upper chamber; 332. control lower chamber; 333. limiting ridge; 4. pressure regulating mechanism; 41. pressure regulating spring; 42. adjusting bolt; 43. adjusting bracket; 44. spring lower pad; 45. spring upper pad; 46. adjusting chamber; 47. diaphragm; 51. first conduit; 52. second conduit; 21. center rod; 22. pilot valve seat; 23. valve ball; 24. bottom cover; 25. pilot valve body; 26. inner spring; 27. tower spring; 28. circulation channel. DETAILED DESCRIPTION

[0018] like Figure 1-Figure 3 A diaphragm steam pressure reducing valve shown in the figure comprises a main valve 1 and a pilot valve 2. The main valve 1 comprises a main valve stem 11, a valve disc 12, a main spring 13 and a main valve body 14. The main valve body 14 has an upstream valve chamber 141 and a downstream valve chamber 142. The upper end of the main valve stem 11 is fixedly connected to the valve disc 12. The main spring 13 presses on the valve disc 12. A control mechanism 3 is arranged below the main valve 1. The main valve stem 11 is responsible for connecting the valve disc 12 and the control mechanism 3, transmitting the force, and realizing the opening and closing action of the valve disc 12. The valve disc 12 is located at the upper end of the main valve stem 11, directly contacts the main spring 13, and is used to control the flow of steam through the opening of the main valve 1. The control mechanism 3 includes a control diaphragm 31, a diaphragm tray 32 and a control housing 33. The control housing 33 is fixedly installed at a position below the main valve body 14. The lower end of the main valve stem 11 penetrates into the control housing 33 and is fixedly connected to the diaphragm tray 32. The middle position of the control diaphragm 31 is tightly fitted with the diaphragm tray 32. The diaphragm tray 32 only needs to contact the control diaphragm 31. The edge of the control diaphragm 31 is fixedly installed in the control housing 33, so that the inner cavity of the control housing 33 is isolated and divided into a control upper cavity 331 and a control lower cavity 332; the pilot valve 2 is installed on the main valve body 14 and the inlet of the pilot valve 2 is connected to the upstream valve cavity 141, and the outlet of the pilot valve 2, the downstream valve cavity 142, and the control lower cavity 332 are connected to each other through the first conduit 51. The diaphragm tray 32 is connected to the main valve stem 11, and the displacement of the control diaphragm 31 is converted into the up and down movement of the main valve stem 11, so that it can respond to the pressure change of the control lower chamber 332, drive the main valve stem 11 and the valve disc 12 to move, and realize the opening and closing control of the main valve 1. The pilot valve 2 first senses the pressure change of the upstream valve chamber 141, and changes the pressure of the control lower chamber 332 by adjusting its own opening, and then acts on the control diaphragm 31. The control diaphragm 31 not only responds to the control adjustment from the pilot valve 2, but also receives the reverse force of the main spring 13, so that the control diaphragm 31 can more accurately adjust the opening of the main valve 1 and improve the accuracy of pressure control.

[0019] A pressure regulating mechanism 4 for regulating the pilot valve 2 is arranged above the main valve 1. The pressure regulating mechanism 4 includes a pressure regulating spring 41, an adjusting bolt 42 and an adjusting bracket 43. The adjusting bracket 43 is fixed above the pilot valve 2. The two ends of the pressure regulating spring 41 are respectively covered with a spring lower pad 44 and a spring upper pad 45. The elastic force of the pressure regulating spring 41 acts on the spring lower pad 44 and the spring upper pad 45. The adjusting bolt 42 is threadedly installed on the adjusting bracket 43 and the lower end of the adjusting bolt 42 presses on the spring upper pad 45; the spring lower pad 44 is floatingly installed in the adjusting bracket 43 and a closed regulating chamber 46 is formed below the spring lower pad 44. The regulating chamber 46 is connected to the downstream valve chamber 142 through a second conduit 52; the pilot valve 2 includes a floating opening and closing center rod 21, and the top of the center rod 21 is in contact with the spring lower pad 44. Rotate the adjusting bolt 42 to adjust the elastic pressure of the pressure regulating spring 41 on the spring pad 44, thereby affecting the pre-pressure on the center rod 21, moving and adjusting the position of the center rod 21, and thus adjusting the opening of the valve ball 23. The pressure of the downstream valve cavity 142 affects the regulating cavity 46, and any change in the downstream pressure is quickly fed back to the center rod 21, causing the valve ball 23 to move upward to reduce the opening or downward to increase the opening, thereby dynamically adjusting the output pressure.

[0020] The control housing 33 is integrally provided with a limiting ridge 333 protruding toward the control lower cavity 332, and the limiting ridge 333 abuts against the diaphragm tray 32 to form a limit. When the valve flap 12 is fully closed, the limiting ridge 333 abuts against the diaphragm tray 32 to prevent the diaphragm tray 32 from moving further downward.

[0021] The bottom surface of the spring lower pad 44 is covered with a diaphragm 47 , which isolates and closes the regulating chamber 46 . The diaphragm 47 extends up and down along with the spring lower pad 44 .

[0022] The pilot valve 2 also includes a pilot valve seat 22, a valve ball 23, a bottom cover 24, a pilot valve body 25, an inner spring 26 and a tower spring 27. The pilot valve body 25 is installed between the adjustment bracket 43 and the main valve body 14. The pilot valve seat 22 is fixed on the pilot valve body 25. A flow channel 28 is opened in the pilot valve seat 22. The center rod 21 movably penetrates the flow channel 28. The inner spring 26 is sheathed on the center rod 21 and the elastic force of the inner spring 26 acts on the center rod 21. The cover 24 is fixed to the bottom of the pilot valve seat 22, the tower spring 27 is installed in the bottom cover 24, and the two ends of the tower spring 27 press on the bottom cover 24 and the valve ball 23, the bottom end of the center rod 21 is pressed against the valve ball 23, and the valve ball 23 is floatingly arranged at the channel opening of the circulation channel 28; the inlet of the pilot valve 2 is opened on the bottom cover 24, the outlet of the pilot valve 2 is located in the pilot valve body 25, and the circulation channel 28 is connected with the inlet and outlet of the pilot valve 2 respectively. Under the adjustment of the pressure regulating spring 41, by applying a certain pressure to the center rod 21, the center rod 21 is pushed to move downward to a certain preset position, so that the center rod 21 pushes the valve ball 23 off the valve seat, so that the pilot valve 2 is opened, and the upstream fluid enters the control device of the pressure reducing valve through the pilot valve 2 through the pipeline, providing thrust for the main valve 1 disc of the pressure reducing valve, so that the pressure reducing valve is opened, and the high-pressure gas enters the use end after the valve is reduced by the pressure reducing valve, providing the user with a fluid of suitable pressure.

[0023] The working principle of the pressure reducing valve is:

[0024] 1. Pressure regulating mechanism 4 adjustment

[0025] Rotate the adjusting bolt 42 to adjust the pressure of the pressure-adjusting spring 41 on the spring pad 44. The center rod 21 of the pilot valve 2 moves according to the pressure change below the spring pad 44. The movement of the center rod 21 adjusts the gap between the valve ball 23 and the pilot valve seat 22, thereby changing the opening of the pilot valve 2 and controlling the steam flow through the pilot valve 2.

[0026] 2. Upstream pressure sensing:

[0027] The pilot valve 2 senses the change in pressure of the upstream valve chamber 141 , and the pressure steam fluid of the upstream valve chamber 141 enters through the inlet of the pilot valve 2 and passes through the flow channel 28 .

[0028] 3. Main valve 1 is opened:

[0029] The change of steam flow at the outlet of the pilot valve 2 directly affects the pressure of the control lower chamber 332. The change of the pressure of the control lower chamber 332 acts on the control diaphragm 31, affecting the displacement of the diaphragm tray 32, thereby driving the up and down movement of the main valve stem 11 and the valve disc 12. The top pressure of the main spring 13 on the valve disc 12 and the pressure on the control diaphragm 31 form a force balance to control the opening of the main valve 1.

[0030] When the pressure in the lower control chamber 332 increases, the control diaphragm 31 is pushed upward, so that the opening degree of the main valve 1 flap increases, and the steam flow rate increases; conversely, when the pressure in the lower control chamber 332 decreases, the main spring 13 pushes the control diaphragm 31 downward, the opening degree of the main valve 1 flap decreases, and the steam flow rate decreases.

[0031] 4. Stable pressure:

[0032] As the steam flow passes through the main valve 1, the increment of the pressure in the downstream valve chamber 142 is fed back to the regulating chamber 46 through the conduit, acting on the diaphragm 47, balancing the pressure of the pressure regulating spring 41 on the upper part of the diaphragm 47, causing the center rod 21 to move upward, and the valve ball 23 moves upward to close the flow channel 28, maintain the pressure on the control diaphragm 31, and control the opening of the main valve 1 to deliver a preset amount of steam to the downstream valve chamber 142.

[0033] The entire valve achieves fine adjustment of the pressure in the downstream valve chamber 142 through pre-adjustment of the pilot valve 2 and precise control of the main valve 1. Even if the upstream pressure or downstream load changes, the system can respond quickly to maintain the stability of the downstream pressure.

Claims

1. A diaphragm type steam pressure reducing valve, comprising a main valve and a pilot valve, wherein the main valve comprises a main valve stem, a valve disc, a main spring and a main valve body, wherein the main valve body has an upstream valve chamber and a downstream valve chamber, and is characterized in that: The upper end of the main valve stem is fixedly connected to the valve disc, and the main spring presses on the valve disc. A control mechanism is arranged below the main valve, and the control mechanism includes a control diaphragm, a diaphragm tray and a control housing. The control housing is fixed below the main valve body, and the lower end of the main valve stem passes through the control housing and is fixedly connected to the diaphragm tray. The middle position of the control diaphragm fits tightly with the diaphragm tray. The control diaphragm is installed in the control housing and isolates the inner cavity of the control housing into a control upper cavity and a control lower cavity; the pilot valve is installed on the main valve body and the inlet of the pilot valve is connected to the upstream valve cavity, and the outlet of the pilot valve, the downstream valve cavity and the control lower cavity are connected to each other through a conduit.

2. The diaphragm type steam pressure reducing valve according to claim 1, characterized in that: A pressure regulating mechanism for regulating the pilot valve is arranged above the main valve, and the pressure regulating mechanism includes a pressure regulating spring, an adjusting bolt and an adjusting bracket. The adjusting bracket is fixed above the pilot valve, and both ends of the pressure regulating spring are respectively covered with a spring lower pad and a spring upper pad. The adjusting bolt is threadedly installed on the adjusting bracket and the lower end of the adjusting bolt presses on the spring upper pad; the spring lower pad is floatingly installed in the adjusting bracket and a closed regulating chamber is formed below the spring lower pad, and the regulating chamber is connected to the downstream valve chamber through a conduit; the pilot valve includes a floating opening and closing center rod, and the top end of the center rod is in contact with the spring lower pad.

3. The diaphragm type steam pressure reducing valve according to claim 2, characterized in that: The pilot valve also includes a pilot valve seat, a valve ball, a bottom cover, a pilot valve body, an inner spring and a tower spring. The pilot valve body is installed between the adjusting bracket and the main valve body. The pilot valve seat is fixed on the pilot valve body. A circulation channel is opened in the pilot valve seat. The center rod movably passes through the circulation channel. The inner spring is sleeved on the center rod and the elastic force of the inner spring acts on the center rod; the bottom cover is fixed to the bottom of the pilot valve seat, the tower spring is installed in the bottom cover, and the two ends of the tower spring are pressed on the bottom cover and the valve ball, the bottom end of the center rod is tightly pressed on the valve ball, and the valve ball is floatingly arranged at the channel opening of the circulation channel; the inlet of the pilot valve is opened on the bottom cover, and the outlet of the pilot valve is located in the pilot valve body, and the circulation channel is respectively connected with the inlet and outlet of the pilot valve.

4. The diaphragm type steam pressure reducing valve according to claim 1, characterized in that: The control housing is integrally provided with a limiting convex ridge protruding toward the control lower cavity, and the limiting convex ridge abuts against the diaphragm tray to form a limit.

5. The diaphragm type steam pressure reducing valve according to claim 2, characterized in that: The bottom surface of the spring lower pad is covered with a diaphragm, and the diaphragm isolates and closes the regulating cavity.

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