JPH0248713A - Depressurizing valve - Google Patents

Abstract

PURPOSE:To permit a control spring to maintain stable setting pressure without being affected by external force by providing a circular and divided leaf springs on the end surface of a female screw corresponding to the control screw controlling the elasticity of a pressure setting spring. CONSTITUTION:The circular leaf springs 70a and 70b are disposed on the upper end part of a nut 45 being the female screw member and they are fixed by a projecting part 72. The leaf springs 70a and 70b are divided, into four, for example. The leaf spring 70a sequentially warps along the screw thread 74 of the control screw 44 and presses down the control screw 44 by repulsing force. A part where the leaf spring 70b does not hung on the screw thread 74 of the control screw 44 operates on the upper surface of the screw thread 74. Consequently, respective divided leaf springs 70a and 70b pinch the screw thread 74 of the control screw so as to strengthen resistance with respect to the rotation of the screw 44. Thus, the control screw 44 is prevented from rotating even if it is affected by external force and setting pressure can be held constant.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a pressure reducing valve that is attached to a piping system for steam, compressed air, etc. to maintain the fluid pressure on the secondary side at a constant set pressure, and particularly relates to a pressure reducing valve that is installed in a piping system for steam, compressed air, etc. related to pressure reducing valves for

<Prior Art> A conventional pressure reducing valve is as shown in FIG. 3, and is composed of a pressure reducing valve section 2, a steam/water separator section 4, and a drain valve section 6.

The main body 10 has an entrance 12. Valve port 14. An outlet 16 is formed.

Inlet 12 connects to a source of high pressure fluid on the primary side and outlet 16 connects to a low pressure region on the secondary side. The main valve 18 is disposed at the inlet side end of the valve port 14 and is elastically biased by a coil spring.

The piston 20 is slidably disposed within the cylinder 22, and the piston rod 20b is brought into contact with the central protruding rod 18a of the main valve 18 through the valve port 14. The lower surface of the piston 20 and the piston rod 20b are connected by a substantially hemispherical surface. A pilot valve 26 is disposed in a primary pressure passage 24 communicating between the inlet 12 and the upper space of the piston 20, that is, the piston 208. The diaphragm 28 is attached with its outer peripheral edge sandwiched between the seven flange 30, 32. The space below the diaphragm 28 communicates with the outlet 16 through a secondary pressure detection passage 34 .

The head end surface of the valve stem 36 of the pilot valve 26 abuts against the central lower surface of the diaphragm 28 .

A pressure setting spring 40 is brought into contact with the upper surface of the diaphragm 28 via a spring seat 38. The upper end of the pressure setting spring is brought into contact with the lower end of the adjusting screw 44 via a spring retainer 42 and a steel ball 43. A nut 45 having parallel surfaces is fitted from inside the upper end of the spring case 66, and the female threaded portion of the nut 45 and the adjustment screw 44 are screwed together. Part number 47 comes with a lock nut.

By turning the adjustment screw 44 left and right, the elastic force of the pressure setting spring 40 that pushes down the diaphragm 28 changes.

Using the elastic force of the pressure setting spring 40 as a reference value, the diaphragm 28 curves in response to the secondary pressure acting on its lower surface, displacing the valve rod 36 and opening and closing the pilot valve 26. As a result, the -next side fluid pressure increases to the piston chamber 20.
a, the piston 20 is driven to displace the main valve 18, and the fluid at the inlet 12 flows through the valve port 14 to the outlet 16. This automatically operates so that the valve port 14 opens when the fluid pressure on the secondary side decreases and closes when it increases.

A cylindrical partition member 46 is attached below the valve port 14,
An annular space 48 is formed between the main body 10 surrounding the annular space 48, and the upper part of the annular space 48 is passed through a cone-shaped screen 50 to the inlet 12.
The lower part communicates with the upper part of the drain valve chamber 52. Further, the upper part of the drain valve chamber 52 communicates with the valve port 14 through the central opening of the partition member 46 . A swirl vane 54 made of an inclined wall is arranged in the annular space 48.

Therefore, when the valve port 14 opens and the fluid in the inlet 12 passes through the annular space 48, its direction is bent by the swirl vanes 54 and the fluid is swirled. The liquid is shaken out to the outside, hits the surrounding inner wall of the main body, and flows down into the drain valve chamber 52, while the light gas swirls in the center and flows from the central opening of the partition member 46 to the valve port 1.
4, through which it flows away to exit 16.

A drain valve port 58 communicating with the drain port 56 is formed at the bottom of the drain valve chamber 52 . Covered with a float cover 62, a spherical valve float 60 is movably accommodated. A ventilation hole 64 is opened in the upper part of the float cover 62.

Therefore, the valve float 60 floats up and down with the water level in the drain valve chamber 52 to open and close the drain valve port 58, and automatically removes water accumulated in the drain valve chamber 52.

<Problems to be Solved by the Invention> When reducing the pressure of the high-pressure fluid on the primary side to a low pressure using a pressure reducing valve, for example, when reducing the pressure on the -outlet side from 20 Kg/crA to 'lK3/lri, it is difficult to do it all at once. . For this reason, it is common to use separate set pressures for high pressure, medium pressure, and low pressure. Therefore, the object of the present invention is low pressure, and even micro pressure (for example, set pressure 0.1 to 1
K'j/cra), the pressure setting spring is very weak, that is, the spring constant is small.

Therefore, when setting the pressure, the diaphragm is balanced by a small force from both sides, so the adjusting screw and the female thread are engaged with each other with only a small force.

For this reason, there is a problem in that the adjusting screw is rotated by a slight external force, or the set pressure is changed simply by pressing the adjusting screw from above.

Also, when tightening the lock nut to secure the adjustment screw, the adjustment screw may rotate together and the set pressure may change.

Therefore, a technical object of the present invention is to provide a pressure reducing valve for setting a low pressure, in which the adjusting screw maintains a stable set pressure without being affected by external force.

<Technical means for solving the problems> The technical means of the present invention taken to solve the above problems are as follows:
A main valve is installed in a valve casing that has an inlet and an outlet, and the secondary side pressure is detected by a pressure detection part that has a diaphragm and a pressure setting spring, and the secondary side is set based on the mechanical output of the pressure detection part. In the pressure reducing valve configured to open and close the main valve to adjust the pressure, an annular and divided plate spring is provided on the end face of the female threaded member corresponding to the adjustment screw that adjusts the elastic force of the pressure setting spring. be.

In addition, as another means, in a pressure reducing valve having the same configuration as above,
A compression spring is interposed between the lower surface of the head of the adjustment screw and the valve casing.

<Function> The annular divided leaf spring provided on the end face of the female threaded member pinches the thread of the adjusting screw from above and below, and as a result, the adjusting screw has a large resistance to rotation, and cannot be rotated by a minute external force. I won't.

Furthermore, even in the case where a compression spring is interposed, the compression spring increases the resistance to rotation of the adjustment screw, so that the adjustment screw does not rotate.

<Example> An example showing a specific example of the above technical means will be described.

The following embodiment is an improved version of the pressure reducing valve shown in Fig. 3.
Components corresponding to the figures are given the same reference numerals, and detailed description of the pressure reducing valve will be omitted.

First embodiment (see Fig. 1) An annular leaf spring 7 is attached to the upper end of a nut 45, which is a female screw member.
0a and 0b are arranged and fixed by caulking with the convex portion 72. Although not shown, the leaf spring is divided into four parts, for example. The leaf spring warps sequentially along the thread 74 of the adjustment screw 44 and presses the adjustment screw with its reaction force (leaf spring 70a>. Also, the part of the leaf spring that does not engage the thread of the adjustment screw is bent against the bottom surface of the thread. In effect, the leaf springs 70b) sandwich the threads of the adjusting screw between the respective divided leaf springs, thereby increasing the resistance to rotation of the screw. Therefore, the adjustment screw does not rotate even if it receives a minute external force, and the set pressure can be kept constant.

Second Embodiment (See FIG. 2) A compression spring 80 is interposed between the lower surface 44b of the head 44a of the adjusting screw 44 and the upper end 66a of the spring case 66. Therefore, the adjustment screw has a greater resistance to rotation due to the action of the compression spring, and the same effect as described above is obtained.

<Effects of the Invention> The adjustment screw rotates more firmly, does not rotate against minute external forces, and maintains the set pressure constant. Further, since the adjustment screw is difficult to rotate, it is not necessary to fix it, that is, a lock nut is not required.

1st) Older brother

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention, FIG. 2 is a sectional view of a main part of another embodiment of the invention, and FIG. 3 is a sectional view of a conventional pressure reducing valve. 2: Pressure reducing valve section 6: Drain valve section 12: Inlet 16; Outlet 26: Pilot valve 44: Adjusting screws 70a, b: Plate spring Steam water separator section Main body Valve port Piston Diaphragm nut Compression spring connector 21

Claims (1)

[Claims] 1. A main valve is provided in a valve casing having an inlet and an outlet,
Pressure reduction configured to detect the secondary side pressure with a pressure detecting section having a diaphragm and a pressure setting spring, and open and close the above-mentioned main valve so as to set the secondary side to the set pressure based on the mechanical output of the pressure detecting section. 1. A pressure reducing valve, characterized in that an annular divided leaf spring is provided on the end face of a female threaded member corresponding to an adjustment screw for adjusting the elastic force of a pressure setting spring. 2. A main valve is provided in a valve casing having an inlet and an outlet,
Pressure reduction configured to detect the secondary side pressure with a pressure detecting section having a diaphragm and a pressure setting spring, and open and close the above-mentioned main valve so as to set the secondary side to the set pressure based on the mechanical output of the pressure detecting section. A pressure reducing valve characterized in that a compression spring is interposed between the lower surface of the head of the adjusting screw and the valve casing.