JPH034868Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a diaphragm valve in which a closing member for opening and closing a fluid passage is composed of a diaphragm, and is suitable for opening and closing passages in fluid systems that handle various gases and liquids. used.

Prior Art and Problems There is known a diaphragm valve that is combined with an electromagnetic pilot valve to perform fluid control as an electromagnetic on-off valve.

FIG. 8 shows an example of this, showing a valve body 4 and a lid 5 having a fluid inlet 1, an outlet 2, and a valve seat 3.
A diaphragm 6 with its peripheral edge sandwiched and fixed between the diaphragm 6 and the diaphragm 6 was disposed opposite the valve seat 3, and a pilot valve body 8 was installed in the electromagnetic coil 9 in contact with a pilot valve seat 7 fixed to the center of the diaphragm 6. pole piece 10
The fluid at the inlet 1 is introduced into a back chamber 12 surrounded by a lid 5 and a diaphragm 6 through an introduction path 14 having a manual control valve 13. It's summery.

Plunger 1 pressed by spring 15 when not energized
The pilot valve body 8 of the pilot valve 1 contacts the pilot valve seat 7 and closes the pilot valve hole 16 that communicates the back chamber 12 with the outlet 2, and since the fluid pressures in the inlet 1 and the back chamber 12 are equal, the diaphragm 6 closes the valve It is seated on the seat 3 and closes the fluid passage. When the electromagnetic coil 9 is energized, the plunger 11 is attracted to the pole piece 10, so the pilot valve body 8 is separated from the pilot valve seat 7, and the fluid in the back chamber 12 is discharged through the pilot valve hole 16 to the low pressure outlet 2. Possibly entrance 1
The fluid pressure pushes the diaphragm 6 away from the valve seat 3 and opens the fluid passage.

According to this configuration, the fluid at the inlet 1 is introduced into the back chamber 12 through the introduction path 14 which is constantly throttled by the manual control valve 13, so if the fluid pressure at the inlet 1 is high when the valve is closed, and when the pressure is low In comparison, the diaphragm 6 sits on the valve seat 3 at a high speed, causing not only a loud impact sound but also the occurrence of water hammer and damage to the diaphragm 6.
There are concerns about damage to the product.

Purpose of the invention This invention is a diaphragm valve that controls the inlet fluid introduced into the back chamber of the diaphragm according to pressure when the valve is closed, and that closes the valve smoothly over a wide pressure range without generating water hammer. is intended to provide.

Means for Solving the Problems The present invention includes a valve body having a fluid inlet and outlet and a valve seat, a diaphragm disposed opposite to the valve seat to block or communicate the inlet and outlet, and a diaphragm that from a pilot valve seat fixed to a diaphragm and a pilot valve body provided on an electromagnetically driven plunger, which has a pilot valve hole that communicates the outlet with a back chamber formed on the opposite side of the valve seat by sandwiching the pilot valve seat. In the diaphragm valve, a fixed bleed hole having a fixed effective opening area and a variable bleed hole having an effective opening area that changes depending on fluid pressure communicate the inlet and the back chamber to the diaphragm. This configuration is a means for solving the above-mentioned problems.

Embodiment The present invention will be explained based on an embodiment shown in the drawings. In FIG. 1, a fluid inlet 21 and an outlet 2
A diaphragm 26 whose peripheral edge is sandwiched and fixed between a valve body 24 having an upwardly facing valve seat 23 formed between the valve body 24 and a lid body 25 attached to the upper part of the valve body 24 faces the valve seat 23. A coil case 28 containing an electromagnetic coil 27 is mounted on the lid 25.

A space surrounded by the lid body 25 and the diaphragm 26 forms a back chamber 29, and the diaphragm 26
A pilot valve seat 31 is fixed to the center of the back chamber 2 and has a pilot valve hole 30 that communicates the back chamber 29 and the outlet 22.
A pilot valve 34 is formed with a pilot valve body 33 provided on the end face of the plunger 32 projecting from the plunger 9 . The plunger 32 and the pilot valve seat 31 are connected by a coiled connection spring 35, and the plunger 32 is attracted by a pole piece 36 installed in the electromagnetic coil 27 to open the pilot valve 34 or release the spring 37. The pilot valve 34 is closed by the elastic force.

A thick wall portion 26a that bulges toward the back chamber 29 is formed in the center of the diaphragm 26, and a disk-shaped diaphragm receiver 38 is stacked on top of the outer peripheral edge portion 38a of the diaphragm 26. A gap 39 is formed between the outer side portion of 26a. In addition, two through holes 40 and 41 are provided in the diaphragm receiver 38 at centrally symmetrical positions, and a fixed bleed hole 4 is provided with a gap 39 in between.
2 and a variable bleed hole 43 are provided in the diaphragm 26 opposite the through holes 40 and 41.

When the electromagnetic coil 27 is deenergized and deenergized, the pilot valve 34 is closed and the inlet 2
The fluid pressure of No. 1 is introduced into the back chamber 29 through the fixed bleed hole 42 and the variable bleed hole 43 and equal pressure is applied to both sides of the diaphragm 26, so the diaphragm 26 seats on the valve seat 23 and closes the fluid passage. There is.

When the electromagnetic coil 27 is energized and energized, the pilot valve 34 opens and transfers the fluid pressure in the back chamber 29 to the outlet 2.
2, the fluid pressure at the inlet 21 pushes the diaphragm 26 away from the valve seat 23 and opens the fluid passage.

At this point, when the electromagnetic coil 27 is de-energized, the pilot 34 closes and the fluid pressure at the inlet 21 passes through the fixed bleed hole 42 and the variable bleed hole 43 to the back chamber 2.
9 and increases the pressure in the back chamber 29 to seat the diaphragm 26 on the valve seat 23. At this time, when the fluid pressure at the inlet 21 is low, the diaphragm 26
Since the amount of deformation of
figure). When the fluid pressure at the inlet 21 is high, the diaphragm 26 moves toward the outer peripheral edge 38 of the diaphragm receiver 38.
pressed against a. At this time, the fixed bleed hole 4
2 overlaps with the opposing through hole 40 to introduce fluid pressure into the back chamber 29 without change, but the variable bleed hole 43 allows the diaphragm 26 to approach and then contact the outer peripheral edge 38a, gradually increasing the contact area. Accordingly, the effective area of the opening is reduced until it is almost completely closed, and there is little or no overlap with the opposing through hole 41 (FIG. 3).

That is, the effective opening area of the variable bleed hole 43 is automatically adjusted according to the fluid pressure, so that the pressure rise in the back chamber 29 is made slow at high pressures, and the fluid passage is not suddenly closed.

In this embodiment, since the two bleed holes 42 and 43 are provided at centrally symmetrical positions, the diaphragm 2
6 has little inclination and the durability of the contact surface is improved, making it suitable for large diameter valves.

In the embodiment shown in FIGS. 4 and 5, one through hole 44 is provided in the diaphragm receiver 38, and the gap 3 of the diaphragm 26 is
A fixed bleed hole 4 is located at the opposite location with 9 in between.
2 and a variable bleed hole 4 on the side thereof.
3, the variable bleed hole 43 comes into contact with the diaphragm receiver 38 during the valve closing operation, reducing the effective opening area (see FIG. 6). In this embodiment, the two bleed holes 42 and 43 are provided close to each other, making it suitable for small diameter valves.

In the embodiment shown in FIG. 7, a fixed bleed hole 42 is provided in the diaphragm 26 at the outer side of the diaphragm receiver 38 which does not have a through hole, and a variable bleed hole 43 is provided toward the outer peripheral edge of the diaphragm receiver 38. In this embodiment as well, the variable bleed hole 4 increases as the fluid pressure increases.
The effective opening area of No. 3 becomes smaller.

In addition, the fixed bleed hole 42 and the variable bleed hole 43
A plurality of these may be provided, or one may be one and the other may be a plurality.

Effects of the invention According to the invention, a fixed bleed hole and a variable bleed hole are provided in the diaphragm to guide the fluid pressure at the inlet to the back chamber, and the variable bleed hole is made by utilizing the deformation of the diaphragm due to the fluid pressure at the inlet. Since the effective opening area is changed, the pressure introduced into the back chamber when the valve closes quickly becomes equal to the fluid pressure at the inlet when the pressure is low, but slowly becomes equal when the pressure is high, and therefore the valve closing speed at high pressure is This eliminates the inconveniences of low pressure and loud impact noise, water hammer, and damage to the diaphragm, and smooth valve closing operation can be expected.

In addition, since the fixed bleed hole always communicates the inlet and the back chamber with a fixed effective opening area, not only can the valve closing speed be increased to the extent that the above-mentioned inconvenience does not occur, but also the fixed bleed hole Even if any of the variable bleed holes becomes blocked by solid matter in the fluid, the valve closing function will not be lost.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an embodiment of the present invention, FIG.
FIG. 3 is an enlarged partial view illustrating the operating situation, FIG. 4 is a vertical cross-sectional partial view of a different embodiment of the present invention, FIG. 5 is a plan view thereof, and FIG. 6 is a diagram showing the operating situation.
FIG. 7 is a vertical cross-sectional partial view of still another embodiment of the present invention, and FIG. 8 is a vertical cross-sectional view of a conventional example. 21...Inlet, 22...Outlet, 23...Valve seat,
24...Valve body, 26...Diaphragm, 27...
...Electromagnetic coil, 29...Back chamber, 31...Pilot valve body, 32...Plunger, 33...Pilot valve body, 34...Pilot valve, 42...Fixed bleed hole, 43...Variable bleed hole.

Claims (1)

[Scope of utility model registration request] A valve body having a fluid inlet and outlet and a valve seat; a diaphragm disposed opposite to the valve seat to block or communicate the inlet and outlet; A diaphragm valve comprising a pilot valve seat fixed to a diaphragm having a pilot valve hole communicating with the back chamber and the outlet, and a pilot valve comprising a pilot valve body provided on an electromagnetically driven plunger, A diaphragm valve characterized in that a fixed bleed hole with a fixed effective opening area and a variable bleed hole with an effective opening area that changes depending on fluid pressure are provided in the diaphragm and communicate with the inlet and the back chamber.