JPH0328215Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a pressure type vacuum breaker for preventing backflow due to a reverse siphon effect that occurs when negative pressure is generated in a pipe.

Prior art In general, piping parts of water supply and hot water supply systems, for example,
As shown in the figure, a vacuum breaker 4 is attached to the water supply branch pipe 3 between the water main pipe 1 and the water supply pipe 2, so that in the unlikely event that the water main pipe 1 is cut off or the pressure is reduced, negative pressure may occur inside the pipe. When the sewage 5 tries to flow into the main water pipe 1 through the hose 6, the drain 2, and the water supply branch pipe 3 due to reverse siphon action, the vacuum breaker 4 automatically releases the water to the negative pressure part in the pipe. Atmospheric air was introduced to prevent such backflow. As shown in FIG. 4, for example, a conventional vacuum breaker of this kind is installed in the middle of a water supply branch pipe 3, and includes an inlet 11a, an outlet 11b, a valve seat 11c, and an intermediate wall 11 projecting inward.
d and has an open top, and when the valve body 11 is seated on the valve seat 11c and closed due to the elasticity of the non-return valve spring described below, and the pressure of the flowing water entering from the inlet 11a exceeds a predetermined value, the spring described below A check valve 12 that rises and opens against a check valve spring, a spring receiver 13 fixed to the lower surface of the intermediate wall 11d, and a check valve 12 that is interposed between the spring receiver 13 and the check valve 12. A check valve spring 14 that gives the check valve 12 a closing habit is screwed onto the top opening of the valve box 11 via an O-ring 15, and has a sufficient passage area between the valve seat 16a and the surrounding wall. Intake ports 16 provided all around the body
b, and an intake valve rod 1 whose upper end is screwed onto the top wall of the valve cover 16 and is allowed to hang down.
7, the intake valve rod 17 is fitted so as to be slidable up and down from the lower end to the center thereof, and is opened by being lowered by its own weight.
The intake valve 18 floats up due to the buoyancy of the flowing water that has entered the interior, and when the pressure of the flowing water exceeds a predetermined value and the acting thrust increases, the intake valve 18 seats on the valve seat 16a and closes against the intake valve spring, which will be described later. A spring receiver 19 is fitted vertically and slidably from the center to the upper part of the valve stem 17, and is interposed between the top wall of the valve cover 16 and the spring receiver 19, so that the intake valve 18 is in the raised position. An intake valve spring 20 is fixed to the top surface of the valve cover 16 with a screw 21 to limit the range of water leakage from the intake port 16b, and to prevent dust from entering from outside. The cap 22 prevents the intake port 16b from getting dirty. When the flowing water enters the inlet 11a and the flowing water pressure reaches a predetermined value (for example, 0.1 Kgf/cm ² ), the check valve 1
2 is opened and flowing water flows to the outlet 11b, and at the same time the water level inside the valve box 11 rises and floats the intake valve 18. However, if the flowing water pressure is low, the intake valve 18 is moved to the valve seat 16.
A part of the flowing water does not sit on the intake valve 18 and the valve seat 16.
leaks to the outside from the intake port 16b through the space between
The water pressure increases further and the pressure inside the valve box exceeds a predetermined value (for example, 0.1 kg, which is slightly higher than atmospheric pressure)
f/cm ² or more), the intake valve 18 is closed and water leakage from the intake port 16b is also stopped (see Figure 5).
Water is flowing in water branch pipe 3. ), or if negative pressure occurs in the water main pipe 1 due to a water outage, etc., the inlet 1
When the water pressure in 1a decreases and the valve closes due to the elasticity of the check valve spring 14, the water main 1 of the waste water 5 is closed.
If the check valve 12 does not close completely, water will flow backwards from the outlet 11b, but in such a case, the pressure inside the valve box will be lower than a predetermined value, so the intake valve 18 opens at a pressure slightly higher than atmospheric pressure (water leakage occurs immediately after this, but the amount is extremely small), and the atmosphere is introduced into the valve box 11, completely preventing suction of waste water. was.

However, this conventional vacuum breaker
Even if the area of water leakage that occurs when the water begins to flow after being installed in the pipe is restricted by the cap 22, the leakage water itself will overflow from the entire circumference of the valve cover 16, so it must be allowed to flow directly to the floor below or to a vacuum. We used a water container placed under the breaker to catch the water, so if you are in a place where water can flow directly to the floor, there is no problem, but if it is installed in the ceiling etc. I was having a hard time. Also, if leakage water cannot be treated, it may become virtually impossible to install it on piping.
There was also the problem of problems with piping construction.

Purpose In view of the above-mentioned problems, the present invention has developed a vacuum breaker that prevents water from leaking at the beginning of water flow, and that can be installed at any location on the piping without causing any problems during piping construction. This is what we intend to provide.

Overview The vacuum breaker according to the present invention is provided with a diaphragm directly below the intake valve that separates the inflow side and the outflow side, and when the inflow pressure exceeds a predetermined pressure that is lower than the force that opens the check valve. The diaphragm area is set so that the diaphragm closes the intake valve, and the check valve opens after the intake valve is closed.

Embodiment Hereinafter, the present invention will be explained in detail based on an embodiment shown in FIGS. 1 and 2, with the same reference numerals given to the same members as in the above conventional example.
The diaphragm fixing ring 24 is arranged so that the peripheral edge of the diaphragm fixing ring 24 is located directly below the intermediate wall 11e of the valve body 11.
The diaphragms 25 and 26, which are fixed to the diaphragm 23 and separate the inlet 11a side and the outlet 11b side, are a diaphragm receiver and a diaphragm presser fixed to the center of the diaphragm 23, respectively, and the fluid pressure is controlled by the check valve. When the pressure exceeds a predetermined pressure that is lower than the pressure that opens the check valve 12 against the spring 14, the diaphragm 23 moves upward against the intake valve spring 20 to close the intake valve 18. The diaphragm area is set to . In addition, 27 is a bottom cover.

Since the vacuum breaker according to the present invention is constructed as described above, firstly, the intake valve 18 when no water is flowing.
As shown in FIG. 1, the diaphragm 23 is separated from the valve seat 16a and lowered by the elasticity of the intake valve spring 20, so that the intake valve 18 is placed on the diaphragm 23. Next, the fluid enters the inlet 11
When the fluid flows into a, the fluid tries to push down the check valve 12, but the check valve 12 is pushed down by the check valve spring 1.
4 imparts a valve closing habit, so the valve does not open until the fluid pressure reaches a certain pressure (for example, 0.1 Kgf/cm ² ) or higher. On the other hand, the fluid acts on the lower surface of the diaphragm 23 and has a certain fluid pressure (for example, 0.05 Kgf/
cm ² ), the upward force acting on the diaphragm 23 becomes greater than the downward force of the intake valve spring 20, pushing up the diaphragm 23 along with the intake valve 18 and seating the intake valve 18 on the valve seat 16a.
At this time, the check valve 12 remains closed.

Next, the fluid pressure increases to a certain pressure (e.g. 0.1Kg
f/cm ² ), the check valve 12 is pushed down and opened, and the fluid flows toward the outlet 11b. At this time, a part of the fluid flowing to the outlet 11b side flows into the intake valve 1
8, but since the intake valve 18 is already seated, no fluid leaks out from the intake port 16b.

Next, if water is cut off or pressure is reduced on the inlet 11a side for some reason, the check valve 12 is immediately closed by the action of the check valve spring 14 to prevent backflow. Also,
When the fluid pressure on the inlet 11a side becomes even slightly lower than the fluid pressure on the outlet 11b side, the diaphragm 23 receives a downward force on its upper surface and descends, separating from the intake valve 18 as shown in FIG. However, the intake valve 18
remains pressed against the valve seat 16a by the fluid pressure on the outlet 11b side. Therefore, at this time as well, fluid will not leak out from the intake port 16b.
Then, when the pressure on the outlet side 11b side further decreases to below a certain pressure (for example, 0.08 Kgf/cm ² ), the upward force acting on the intake valve 18 is applied to the intake valve spring 20.
Since the force becomes smaller than the downward force of the valve and moves away from the valve seat 16a, atmospheric pressure is introduced into the vacuum breaker from the intake port 16b, thereby preventing backflow due to a reverse siphon effect.

Thus, according to the vacuum breaker of the present invention, since the intake valve 18 is closed before the check valve 12 is opened at the start of water flow, no water leakage occurs at the beginning of water flow, and there is no reverse siphon. Since the open state of the intake valve 18 is maintained even at the initial stage of operation, water leakage does not occur, and therefore, it can be installed at any location on the piping, and there is no problem in piping construction.

Effects of the invention As mentioned above, the vacuum breaker according to the invention does not cause any initial water leakage at the beginning of water flow or during reverse siphon action, and therefore can be installed at any location on the piping without causing any problems during piping construction. It has important practical advantages.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the vacuum breaker according to the present invention, Fig. 2 is a longitudinal sectional view showing the closed state of the intake valve 18 of the above embodiment, and Fig. 3 is the mounting position of the vacuum breaker. FIGS. 4 and 5 are longitudinal sectional views showing the structure and operating state of the conventional example, respectively. 11...Valve box, 11a...Inlet, 11b...Outlet, 12...Check valve, 14...Check valve spring,
15...O ring, 16...Valve cover, 16b...Intake port, 18...Intake valve, 20...Intake valve spring, 2
2...Cap, 23...Diaphragm, 24...
...Diaphragm fixing ring, 25...Diaphragm receiver, 26...Diaphragm presser, 27...Bottom cover.

Claims (1)

[Scope of utility model registration request] The intake valve is installed on the intake side and has an opening behavior that allows the valve to open at an outlet pressure slightly higher than atmospheric pressure due to the intake valve spring, and the intake valve is installed on the inlet side and has a check valve. In a pressure-type vacuum breaker that is equipped with a check valve that has a valve closing habit with a valve spring to prevent backflow due to reverse siphon action, the inlet side and the outlet side are separated directly below the intake valve. A diaphragm is provided separately from the intake valve, and the diaphragm area is set so that the diaphragm closes the intake valve when the inflow pressure exceeds a predetermined pressure that is lower than the pressure that opens the check valve. Vacuum breaker featuring: