JP2841576B2 - Automatic on-off valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pilot type automatic on-off valve having a backflow prevention function.

(Prior Art) In a conventional automatic on-off valve, a diaphragm is openably and closably interposed between an inflow passage and an outflow passage provided in a valve box, and communicates with the inflow passage through a bleed hole on the back surface of the diaphragm. A diaphragm back chamber is formed, and a plunger is driven by a driving solenoid disposed on the diaphragm back chamber to open and close a main valve hole including a diaphragm and a valve seat.

However, when the primary side on the inflow path side has a negative pressure, the diaphragm back chamber has a negative pressure through the bleed hole, and the diaphragm is separated from the valve seat and the secondary side on the outflow path side has a negative pressure. Then, when the above-described automatic opening / closing valve is used in, for example, a flush supply device for a toilet, sewage may flow backward.

Therefore, a check valve is provided on the secondary side to prevent backflow at the time of negative pressure on the primary side, and a vacuum breaker is provided on the secondary side to secure an air gap.

(Problems to be Solved by the Invention) In the conventional technology, a check valve must be provided in the secondary flow path, which is the outflow path, so that the flow path resistance becomes large, the pressure loss becomes large, and piping work is performed. However, there is a problem in that the device becomes large and requires an installation space since it must be disposed together with the vacuum breaker.

The present invention has been made in view of such problems of the conventional technology, and has as its object the following.
It is an object of the present invention to provide an automatic on-off valve in which the diaphragm functions as a check valve at the time of the secondary side negative pressure.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a diaphragm interposed between an inflow passage and an outflow passage provided in a valve box, and forms a diaphragm back chamber on the back surface of the diaphragm. In the automatic opening / closing valve which communicates the diaphragm back chamber with the inflow passage through a bleed hole, a vacuum breaker is provided so as to communicate with the diaphragm back chamber.

(Operation) The present invention configured as described above functions to prevent backflow at the time of primary-side negative pressure.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

 FIG. 1 is a sectional view of an automatic on-off valve according to the present invention.

In the valve box 1, a main valve seat 4 is provided between the inflow passage 2 and the outflow passage 3.
A diaphragm 6 with a retainer 5 supported by the valve box 1 is disposed on the periphery of the upper opening of the main valve seat 4 so as to be able to freely contact and separate therefrom. Therefore, the main valve hole 7 is formed by separating the diaphragm 6 from the main valve seat 4.

A vertically long pilot valve hole 8 is formed at the center of the retainer 5, and an end of the retainer 5 communicates with the diaphragm back chamber 9 provided at the back of the diaphragm 6 and the inflow passage 2, and the pilot Bleed hole smaller in diameter than valve hole 8
10 are formed.

On the pilot valve hole 8, a plunger 12 driven by a solenoid 11 is disposed by being urged in a protruding direction by a coil spring 13, and a pilot valve hole 14 is attached to a lower end of the plunger 12 by a pilot valve hole 14. 8 is opened and closed.
In addition, 15 is a guide sleeve of the plunger 12, and 16 is an iron core.

Further, a vacuum breaker 20 is attached to the valve box 1 so as to communicate with the diaphragm back chamber 9. The vacuum breaker 20 includes a valve hole 23 opened at one end of a body 22 to form a through hole 21, and a contracted coil spring
The valve body 25 is pressed into the valve hole 23 by 24 and the like.

The operation of the automatic on-off valve configured as described above will be described.

When the solenoid 11 is not energized, the plunger 12 is pressed toward the diaphragm 6 by the coil spring 13 as shown in FIG. 1, and the pilot valve hole 8 is closed by the valve element 14 at the tip. Therefore, the fluid in the inflow passage 2 flows into the diaphragm back chamber 9 from the bleed hole 10, and the pressure of the inflowing fluid pushes the diaphragm 6 against the main valve seat 4, so that the main valve hole 7 is closed.

When the solenoid 11 is energized while the main valve hole 7 is closed, the plunger 12 is attracted to the iron core 16 against the coil spring 13, and the valve element 14 separates from the valve seat of the pilot valve hole 8 and the pilot valve The hole 8 is opened. As a result, the fluid in the diaphragm back chamber 9 flows out through the pilot valve hole to the outflow passage 3 side. Then, since the diameter of the pilot valve hole 8 is larger than the diameter of the bleed hole 10, the outflow amount is larger than the inflow amount of the diaphragm back chamber 9, and the pressure in the diaphragm back chamber 9 is reduced. Therefore, the diaphragm 6 is pushed up by the pressure of the fluid flowing from the inflow passage 2, the diaphragm 6 is separated from the main valve seat 4, and the main valve hole 7 is opened.

Also, when the solenoid 11 is energized and the main valve hole 7 is in an open state, if the primary side, which is the inflow passage 2 side, becomes negative pressure (lower than atmospheric pressure) for some reason, the diaphragm back chamber through the bleed hole 10. 9 also becomes negative pressure. As a result, the valve body 25 of the vacuum breaker 20
Open. Then, the diaphragm back chamber 9 becomes the atmospheric pressure, and the diaphragm 6 is pressed by the main valve seat 4 so that the main valve seat 7
Is closed.

Therefore, the diaphragm 6 functions as a check valve to prevent the backflow, and the check valve on the outflow passage 3 side becomes unnecessary.

Further, even when the main valve hole 7 is in the closed state, when a negative pressure enough to separate the diaphragm 6 from the main valve seat 4 is generated on the primary side, the same operation as described above is performed.

In this embodiment, the present invention is applied to the internal pilot type automatic opening / closing valve, but can also be applied to the external pilot type automatic opening / closing valve.

(Effect of the Invention) As described above, according to the present invention, the diaphragm functions as a check valve at the time of the primary-side negative pressure, so that the check valve is not required. Therefore, reduction in pressure loss, reduction in man-hours for piping, and downsizing can contribute to space saving in installation.

[Brief description of the drawings]

FIG. 1 is a sectional view of an automatic on-off valve according to the present invention. In the drawings, 1 is a valve box, 2 is an inflow path, 3 is an outflow path, 6 is a diaphragm, 9 is a diaphragm back chamber, and 20 is a vacuum breaker.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshinobu Uchimura 2-8-1, Honmura, Chigasaki-shi, Kanagawa Prefecture Inside the Toga Kikai Co., Ltd. Chigasaki Plant (72) Inventor Keiji Horiuchi 2--8, Honmura, Chigasaki-shi, Kanagawa Prefecture No. 1 Tochiki Kikai Co., Ltd. Chigasaki Plant (56) References JP-A-1-135980 (JP, A) JP-A-60-132186 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , (DB name) F16K 31/12-31/165 F16K 31/36-31/42

Claims (1)

(57) [Claims] 1. A diaphragm is interposed between an inflow passage and an outflow passage provided in a valve box, and a diaphragm back chamber is formed on a back surface of the diaphragm, and a bleed hole is formed between the diaphragm back chamber and the inflow path. An automatic on-off valve, wherein a vacuum breaker is provided so as to communicate with the back chamber of the diaphragm.