JPH06281179A - Reverse flow preventive device for hot water supplying device or the like - Google Patents

Abstract

PURPOSE:To prevent the reverse flow of water from a downstream side by closing an overflow hole with a diaphragm valve by the pressing force of the water being poured in a hot water feeder and by a suction force due to negative pressure. CONSTITUTION:When water is being poured in a hot water supplying device from upstream water feed passages U1 and U2, the water is received in a receiving container part 10 and thereafter part of the water enters a pressure application chamber 60 to press a diaphragm value 50 normally spring-biased to be under an open condition to an overflow hole against the force of a spring 51. On the other hand, since a major part of the water passes through an inner cylinderical body 30 as a primary passage, a space S between the inner cylindrical body 30 and an outer cylindrical body 20 becomes a secondary passage which, during water pouring, is made negative in pressure due to the ejector effect resulting from the overflowing from the primary passage. Therefore, the diaphragm value 50 held against the overflow hole 21 from outside is further held thereon by the negative pressure from inside to completely seal the overflow hole 21. In this way this method can prevent the water from reverse flow from the downstream side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow preventive device for preventing backflow of miscellaneous water or the like from a downstream side in a water heater or the like.

[0002]

2. Description of the Related Art As a backflow prevention device of this type, for example, a device described in Japanese Utility Model Laid-Open No. 4-74212 is provided. As shown in FIG. 3, this device is configured to inject water from the hot water supply passage 1 into the bathtub B through the hopper 2 and to provide an overflow chamber 3 adjacent to the hopper 2 and communicating with the hopper 2.
When pouring water, the valve 5 is pushed by the water flowing from the pipe 4 branched from the hot water supply passage 1 to close the drain port 6.

[0003]

However, in the above-mentioned conventional backflow prevention device, since the water pressure for pressing the valve 5 through the pipe 4 is weak, the valve 5 can reliably close the drain port 6 even when pouring water. There was a problem that water could easily leak from the overflow chamber 3 during pouring.

Therefore, according to the present invention, it is possible to solve the above-mentioned drawbacks of the conventional device and prevent the reverse amount of sewage water from the downstream water supply channel. Also in the above, it is an object of the present invention to provide a backflow prevention device in a water heater or the like, which can surely close the overflow port, and thus can reliably prevent leakage of injected water and mixing of air.

[0005]

In order to achieve the above object, a backflow prevention device in a water heater or the like according to the present invention comprises a receiving container portion for receiving hot water or water from an upstream water supply passage through an opening / closing valve, A hopper-shaped drop-out cylinder connected to a drop-out port at the center of the bottom of the receiving container, and a double-tube shape are formed in the drop-out cylinder with a proper gap between the drop-out cylinder and the outer cylinder. Along with this, an inner cylindrical body that allows most of the water from the drop-in port of the receiving container section to flow in and flow out of the apparatus from the lower end opening, an overflow port opened to the side wall of the drop-in outer cylinder body, and the overflow port. A normally open spring-biased diaphragm valve for opening and closing, a pressure chamber for pressing the normally-open spring-biased diaphragm valve toward the overflow port against the spring, and the receiving container in the pressure chamber. In the department It is characterized by having a pressure introduction passage to draw a portion of the water.

[0006]

According to the above feature of the present invention, at the time of water injection, the water injection from the upstream water supply channel enters the receiving container part from the opened on-off valve, and then passes through the drop opening in the center of the bottom to enter the outer cylinder body. Most of it flows into the inner cylinder, and flows out of the device through the lower end opening. Part of the water injected into the receiving container enters the pressure chamber through the pressure introduction passage, presses the normally open spring energized diaphragm valve, and overflows the normally open spring energized diaphragm valve against the energizing spring. Press into your mouth. On the other hand, since most of the water injection passes through the inner cylinder inside the device as a main passage, the gap between the inner cylinder and the outer cylinder serves as a sub passage for water injection, and during water injection, the water flows out from the main passage. Due to the ejector effect due to, the inside of the secondary passage is in a negative pressure state. As a result, the normally open spring-biased diaphragm valve that is pressed from the outside to the overflow port is also sucked by the negative pressure from the inside, and as a result, it tightly adheres to the overflow port and seals. As described above, in the device of the present invention, during water injection, the normally-open spring-biased diaphragm valve is operated so as to be brought into close contact with the overflow port not only by the pressing force using a part of the water injection but also by the negative pressure suction force. , The adhesion becomes stronger,
The overflow port is surely closed. Therefore, even if the flow rate of water injection is low, the overflow port can be reliably sealed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a vertical cross-sectional view of a device for carrying out the present invention, showing a case where water is not poured. FIG. 2 is also a vertical cross-sectional view of the apparatus of the present invention, showing the time when hot water is being supplied as water.

Receiving container part 10 provided at the top of the device
Receives water and hot water from the upstream water supply passages U1 and U2 via electromagnetic on-off valves V1 and V2, respectively. A drop-in port 11 is opened at the center of the bottom of the receiving container part 10, and a drop-in outer cylinder body 20 is connected to the drop-in port 11 so as to communicate therewith. The drop-in outer cylinder body 20 has a hopper shape in which the lower portion is thin. Inside the drop-in outer cylinder body 20, an appropriate gap S is formed with the outer cylinder body 20, and the inner cylinder body 30 is arranged in a double pipe shape. The upper opening 31 of the inner cylindrical body 30 is located directly below the dropping port 11, and most of the water injected from the dropping port 11 flows into the inner cylindrical body 30. That is, the inside of the inner cylinder 30 serves as the main passage for water injection. The inner cylindrical body 30 has a lower portion that is narrowed to form a double cylindrical tube concentric with the outer cylindrical body. A downstream side water supply passage L such as a hose 7 is connected to the double cylindrical pipe. The water that has flowed out of the device from the lower end opening of the inner tubular body 30 flows into the lower water supply passage L.

An overflow port 21 is provided on the side wall of the outer tubular body 20.
Is provided. An air charge chamber 40 is provided outside the overflow port 21, and a normally-open spring-biased diaphragm valve 50 is arranged in the air charge chamber 40. The normally open spring-biased diaphragm valve 50 normally opens the overflow port 21 by the biasing spring 51. A pressure chamber 60 is provided behind the normally open spring-biased diaphragm valve 50, and the pressure chamber 60 is connected to a side portion of the receiving container 10 by a pressure introduction passage 61.

In the above structure, when the water is not injected, the on-off valves V1 and V2 are closed as shown in FIG. 1, so that the water is not injected into the receiving container portion 10, and therefore the pressure introducing passage 61 is not supplied. Since a part of the injected water is not drawn into the pressure chamber 60 through the pressure chamber 60 and the pressure chamber 60 is not pressurized, the diaphragm valve 50 is urged by the urging spring 51 so that the overflow port 21 is closed.
Keep open. Therefore, in this state, when there is a backflow from the downstream side water supply passage L, the backwashed miscellaneous water is surely discharged from the overflow port 21, and the backflow to the upstream side water supply passages U1 and U2 above it. Do not reach

On the other hand, one of the on-off valves V1 and V2,
Alternatively, when both are opened (V2 on the hot water supply side is opened in FIG. 2) and water is injected, the water flows into the receiving container part 10, and most of the water is dropped from the drop port 11 into the outer cylinder 20. Then, most of it flows into the inner cylindrical body 30 which is the main passage, and flows out downward. At this time, due to the momentum of the flow rate flowing out from the inner cylindrical body 30, the gap S between the inner cylindrical body 30 and the outer cylindrical body, which is the slave passage, is in a negative pressure state. Further, a part of the water injected from the receiving container portion 10 is drawn into the pressurizing chamber 60 through the pressure introducing passage 61, and the pressurizing chamber 60 is pressurized by this, and the diaphragm valve 50 resists the spring 51 and overflow port 21. Press on. The pressing force and the suction force due to the negative pressure state of the gap S act on the diaphragm valve 50,
The diaphragm valve 50 surely blocks the overflow port 21,
Overflow under water injection is reliably prevented. Further, the overflow port 21 can be reliably closed even when the amount of injected water is small. Therefore, leakage of water can be prevented and air can be mixed reliably from a large flow rate to a small flow rate.

[0012]

The present invention has the above-described structure and operation. According to the backflow prevention device for a water heater or the like according to claim 1, at the time of water injection, not only the pressing force using a part of the water injection but also the water injection The normally open spring-biased diaphragm valve closes the overflow port in combination with the suction force generated by the negative pressure generation action, so the overflow port can be closed reliably from large flow rate injection to small flow rate injection. Can be done. It is possible to reliably prevent leakage and air inclusion during water injection. Of course, the normally-open spring-biased diaphragm valve surely opens the overflow port when water is not injected, so that backflow to the upstream water supply passage can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a device for carrying out the present invention, showing a state when water is not injected.

FIG. 2 is also a vertical cross-sectional view of the device of the present invention, showing the time when hot water is being supplied as water.

FIG. 3 is a cross-sectional configuration diagram of a conventional device.

[Explanation of symbols]

 10 Receiving container 11 Drop port 20 Drop outer cylinder 21 Overflow port 30 Inner cylinder 50 Normally open spring energizing diaphragm valve 51 Energizing spring 60 Pressurizing chamber 61 Pressure introducing passage S Gap U1, U2 Upstream water supply channel L Downstream Side waterway

Claims (1)

[Claims] 1. A hopper-shaped drop-out outer cylinder which is connected to a receiving container part for receiving hot water or water from an upstream water supply channel through an on-off valve and a drop-in port at the center of the bottom of the receiving container part. And is arranged in a double-tube shape with a proper gap formed between the outer cylinder and the outer cylinder, and most of the water from the drop port of the receiving container is allowed to flow into the outer cylinder from the outside of the device. Inner cylinder to be discharged to
An overflow port opened in the side wall of the drop-out outer cylinder body, a normally-open spring-biased diaphragm valve for opening and closing the overflow port, and an overflow port against the normally-open spring-biased diaphragm valve against the spring. A backflow prevention device in a water heater or the like, comprising: a pressurizing chamber for pressing to the side and a pressure introducing passage for drawing a part of the water injected into the receiving container portion into the pressurizing chamber.