JP3290213B2 - Vacuum pressure reducing valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum pressure reducing valve for setting a secondary pressure to a negative pressure.

[0002]

2. Description of the Related Art In recent years, foods and the like are often industrially heated at a temperature of 100 ° C. or less, and the latent heat of steam is used as a heat source. In this case, since the steam needs to be reduced to the atmospheric pressure or less, for example, 1 kg / cm ^{2 to 2} k
g / cm ² of water vapor is reduced in pressure by a vacuum pressure reducing valve (for example, see Japanese Patent Application Laid-Open No. 2-24707). FIG. 3 shows an example of the vacuum pressure reducing valve.

FIG. 3 shows a control section for controlling the secondary pressure in the vacuum pressure reducing valve. In this figure, the primary pressure is transmitted from the lower primary bypass passage 1 to the piston chamber 3 via the pilot passage 32 of the pilot valve 2. Above the pilot valve 2, a pressure detection chamber 5 is provided. The pressure detection chamber 5 communicates with a secondary passage (not shown) via the secondary pressure transmission passage 4. The pressure detection chamber 5
Is closed by a flexible member 6 composed of a diaphragm, and presses the first spring 11 in the valve closing direction S of the pilot valve 2 due to an increase in negative pressure on the secondary side. The first spring 11 is a compression coil spring that presses the pilot valve 2 in the valve opening direction O. The first spring 11
Of the first spring 1 against the first spring 11
A second spring 12 for compressing the first spring 1 is provided. The second spring 12 is composed of a tension coil spring provided in a normal pressure chamber 33 communicating with the atmosphere, and is capable of closing the pilot valve 2 while a negative pressure is acting on the pressure detection chamber 5. is there. Note that the first spring 11 is
The purpose of this is to reduce the inertia of 2 and prevent the flexible member 6 from vibrating.

Next, the operation of the above configuration will be briefly described. When the pressure in the secondary pressure transmission path 4 falls below a set value, the negative pressure on the lower surface of the flexible member 6 increases, the first spring 11 and the second spring 12 expand, and the pilot valve 2 It moves in the valve opening direction O. Due to this movement, a primary pressure acts on the piston chamber 3 from the bypass passage 1 via the pilot passage 32. As a result, the piston 23 descends to open the main valve (not shown) (hereinafter, referred to as an opening amount).
It is called "opening." ) Increases, and the secondary pressure increases. On the other hand, when the pressure in the secondary pressure transmission path 4 rises above the set value, the negative pressure on the lower surface of the flexible member 6 decreases,
The first and second springs 11 and 12 contract, and the pilot valve 2 moves in the valve closing direction S. With this movement,
The primary pressure acting on the piston chamber 3 from the bypass passage 1 is reduced, whereby the piston 23 rises and the opening of the main valve (not shown) is reduced, so that the secondary pressure is reduced. Thus, the vacuum pressure reducing valve maintains the negative pressure on the secondary side at a constant value.

[0005]

By the way, in a general pressure reducing valve, that is, in a pressure reducing valve which introduces a fluid of several kg / cm ² to the primary side and takes out a fluid of 1 kg / cm ² or more to the secondary side, Since the pressure in the pressure detection chamber 5 is higher than the pressure in the normal pressure chamber 33, in order to close the pilot valve 2 in a state where a positive pressure is acting on the pressure detection chamber 5, (second ) The spring 12 is a compression coil spring. However, in the vacuum pressure reducing valve, the pressure in the normal pressure chamber 33 is higher than the pressure in the pressure detection chamber 5, so that when the same structure as that of the above-described general pressure reducing valve is used, the second spring 12 is pulled into a tensioned coil. It has to be composed of springs. Here, the tension coil spring needs to hook the end of the spring 12 on the engaging portions 7a and 8a of the spring receivers 7 and 8. Therefore, the conventional vacuum pressure reducing valve has a poor assemblability.

In the above-mentioned prior art, the second spring 12
Is constituted by a tension coil spring, it is necessary to pull the flexible member 6 upward. For this reason, the flexible member 6 is pinched between the spring receiver 8 and the pinching member 50 so that the The member 6 is fixed to a spring receiver 8. As described above, in order to clamp and fix the flexible member 6, the spring receiver 8 and the clamping member 50 need to be welded or swaged, so that the assemblability is deteriorated. In addition, since the holding member 50 is fitted into the spring receiver 8 and the holding member 50 has a structure penetrating the flexible member 6, it is necessary to seal this portion, which also deteriorates the assemblability.

[0007] Further, since the flexible member 6 is sandwiched and fixed at the inner peripheral edge thereof, in order to displace the flexible member 6 sufficiently large, the flexible member 6 must be large in the radial direction. Become something. Accordingly, the entire vacuum pressure reducing valve becomes large.

The present invention has been made in view of the above-mentioned conventional problems, and the first and second springs of the vacuum pressure reducing valve are both constituted by compression coil springs to improve the assemblability and reduce the size. The purpose is to plan.

[0009]

In order to achieve the above-mentioned object, the present invention provides a first coil spring and a second coil spring which are opposed to each other via a spring receiver, and a compression coil spring.
Said second spring configured in ring within the pressure detection chamber, before
It is located at the outer periphery of the valve seat on which the valve
And a shaft for moving the valve element in the valve opening direction.
Movably provided on the lube sheet to shrink the flexible member.
Moves the shaft in the valve opening direction.

[0010]

According to the present invention, since the second spring is provided in the pressure detection chamber, even if a negative pressure acts on the pressure detection chamber,
The second spring can be constituted by a compression coil spring.

[0011]

1 and 2 show an embodiment of the present invention.
It is explained according to. In FIG. 2, the lower primary passage 21 communicates with the secondary passage 22 via the main valve 20, but this drawing shows the state in which the main valve 20 is closed. The main valve 20 includes a cup-shaped valve element 24 that opens when the piston 23 descends, and a cylindrical main valve seat 25 that guides the outer periphery of the valve element 24 and abuts on the upper part of the valve element 24. . The main valve seat 25 has several or many holes 25a, and the valve body 24 is constantly urged in the valve closing direction S by the third spring 13 from below. Therefore, the pressure of the piston chamber 3 increases, and the piston 23 moves downward, so that the opening of the main valve 20 increases.

The pilot valve (valve element) 2 at the center of the drawing is normally pressed in the valve closing direction S by a fourth spring 14 as shown in FIG. While the space between 1A is closed, the bypass passage 1 is communicated with the bypass passage 1A by the vertical movement of the pilot shaft 31. The steam St introduced into the piston chamber 3 of FIG. 2 from the bypass passage 1A is led out to the main secondary passage 22 through an escape hole 23a formed in the piston 23.

The pilot valve seat 30 is formed with a pilot passage 32 that communicates with the bypass passage 1 and guides the steam St of the left bypass passage 1 to the piston chamber 3. The pilot shaft 31
Are slidably provided on the pilot valve seat 30.

In FIG. 1, a second spring 12 is provided on the outer periphery of the pilot valve seat 30.
The second spring 12 is formed of a compression coil spring, and is formed on the outer periphery of the flexible member 6 and the pilot valve seat 30 .
Is provided between the step portion 30a and the step portion 30a . The flexible member 6 is formed of a bag-like bellows whose free end 6a is closed,
The pressure detection chamber 5 is formed inside (below). The second spring 12 is disposed in the pressure detection chamber 5.

A normal pressure chamber 33 is provided outside (above) the flexible member 6. The normal pressure chamber 33 communicates with the outside through an atmosphere communication hole 34 and is maintained at normal pressure. Above the second spring 12 in the normal pressure chamber 33, a spring receiver 35 is provided. Through the spring receiver 35, the first spring 11 and the second spring 12
Are opposed to each other. The free end 6a of the flexible member 6 is in contact with the spring receiver 35.

The first spring 11 adjusts the set pressure of the main secondary passage 22 (FIG. 1) by adjusting the spring force by the adjusting male screw 36 and the sleeve 37. The sleeve 37 penetrates the adjusting male screw 36 and engages with the cap 38 in the circumferential direction, and moves up and down by rotation of the adjusting male screw 36. The adjusting male screw 36 is provided with the cap-shaped handle 3.
Rotates with 9. Other configurations are the same as those of the above-described conventional example, and the same or corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.

Next, the operation of the above configuration will be described. First, the handle 39 is rotated so that the first spring 11
Adjust the spring force of. In FIG. 2, the pilot valve 2
Is closed, the main valve 20 is also closed. When the water vapor St in the main secondary passage 22 is sucked, the pressure in the pressure detection chamber 5 decreases through the secondary pressure transmission passage 4,
Along with this, the flexible member 6 shrinks. As a result, the spring receiver 35 moves downward, the pilot shaft 31 pushes the pilot valve 2 downward, and the bypass passage 1 communicates with the pilot passage 32. By this communication, the steam St of the main primary side passage 21 is introduced into the piston chamber 3 via the bypass passage 1, the pilot passage 32 and the bypass passage 1A, and the piston 23 descends. The lowering of the piston 23 causes the main valve 20 to open, and the steam in the main primary passage 21 is decompressed and led out to the secondary passage 22.

In the above configuration, since the first spring 11 and the second spring 12 are opposed to each other via the spring receiver 35 and the second spring 12 is provided in the pressure detection chamber 5, the pressure detection chamber Even if a negative pressure is acting on 5, the second spring 12 can be constituted by a compression coil spring. Unlike the tension coil spring, the second spring 12 composed of the compression coil spring does not require a part of the spring to be hooked on the spring receiver 35, so that the assemblability is improved.

Further, since the second spring 12 is constituted by a compression coil spring, there is no need to pull the flexible member 6 upward, and the flexible member 6 can be moved by the spring force of the second spring 12. May be pushed upward. Therefore, the free end 6a of the flexible member 6 does not need to be held and fixed by the spring receiver 35.
This eliminates the need for caulking. Therefore, assemblability is also improved.

Further, as described above, since there is no need to pinch and fix the free end 6a of the flexible member 6, the structure is such that the free end 6a of the flexible member 6 is closed. Therefore, it is not necessary to seal this portion, so that the assemblability is also improved.

Since the free end 6a of the flexible member 6 does not need to be fixed to the spring receiver 35, the size of the free end 6a can be reduced, and the size of the flexible member 6 can be reduced. Therefore, the size of the entire vacuum pressure reducing valve can be reduced.

In the above-described embodiment, the pilot valve 2 is provided, and the opening of the pilot valve 2 is changed to change the main valve 20.
Although the description has been given of the vacuum pressure reducing valve for adjusting the opening degree, the present invention can also be applied to a direct acting vacuum pressure reducing valve not provided with the pilot valve 2.

[0023]

As described above, according to the present invention, not only the first spring but also the second spring is constituted by a compression coil spring, so that the assemblability is improved and
The size of the vacuum pressure reducing valve can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a control section of a vacuum pressure reducing valve showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the vacuum pressure reducing valve.

FIG. 3 is a longitudinal sectional view of a control section of a conventional vacuum pressure reducing valve.

[Explanation of symbols]

2 ... valve element (pilot valve), 5 ... pressure detection chamber, 6 ... flexible member, 11 ... first spring, 12 ... second spring, 22 ...
Secondary passage, 35: spring receiver, O: valve opening direction, S: valve closing direction.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05D 16/00-16/20

Claims (1)

(57) [Claims] 1. A first spring comprising a compression coil spring for pressing a valve body in a valve opening direction, a second spring for compressing the first spring against the first spring, and a flexible member. A pressure detecting chamber closed by a member, and communicating with the secondary side passage and pressing the first spring in the valve closing direction by a pressure increase of the negative pressure on the secondary side; The first spring and the second spring are opposed to each other via a spring receiver, and are constituted by a compression coil spring.
The second springs, within the pressure detection chamber, the valve body
Provided on the outer periphery of the valve seat on which the
The shaft that moves the valve body in the valve opening direction is
Movably provided on the front end of the flexible member,
A pressure reducing valve for vacuum, wherein the shaft is moved in a valve opening direction .