JPH06281177A - Reverse flow preventive device for hot water supplying device or the like - Google Patents

Abstract

PURPOSE:To provide a reverse flow preventive device, for use in hot water supplying device, which can accurately prevent the overflowing of water when it is being poured therein and the flowing of the water to the upstream side in case of reverse flow and which is compact in overall size. CONSTITUTION:The inner space provided in a reverse flow preventive device body 10 is divided into a primary space 20 connected to the upstream side of a hot water passage and a secondary space 30 connected to the downstream side thereof by a diaphragm valve 40 biased by a spring 41 and, by the side of the secondary space 30, is provided an overflow passage opening 81 which is closed when the diaphragm valve 40 is forced against the secondary space 30 by the pressure applied from the primary space, 20. To the central part of the diaphragm valve 40, is mounted a water feed passage forming body 90 provided with a water feed passage hole 92 communicating with the primary space 20 and the secondary space 30 and a water feed passage valve 94 biased by a spring 93 and adapted to release the water feed passage hole 92 when a higher pressure than that for forcing the diaphragm valve 40 against the secondary space 30 through the water feed passage hole 92 is exerted on the diaphragm valve 40 from the primary space 20.

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 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. 2, this device is configured to inject water from a hot water supply passage 1 into a bathtub B through a hopper 2 and to provide an overflow chamber 3 adjacent to the hopper 2 and communicating with the hopper 2. 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. However, there was a problem that water could easily leak from the overflow chamber 3. Further, since it is provided separately from the hopper 2, there is a problem that the volume becomes large as a whole.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional device, can reliably prevent the generation of overflow water at the time of water injection, and can reliably prevent the backflow to the upstream side when the backflow occurs. It is also an object of the present invention to provide a backflow prevention device for a water heater or the like that is compact as a whole.

[0005]

In order to achieve the above object, in the backflow prevention device for a water heater or the like of the present invention, the device body is connected as a unit in the middle of the hot water supply passage, and the backflow from the downstream side is the device. A backflow prevention device for a hot water supply device or the like for preventing backflow to the upstream side of the main body, wherein the inner space provided in the main body of the device is connected to the upstream side of the hot water supply passage and the downstream side of the hot water supply passage. The secondary space connected to is separated by a spring-biased diaphragm valve,
The side portion of the secondary space is provided with an overflow passage port that is closed when the spring-biased diaphragm valve is pushed to the secondary space side by the pressure of the primary space side, and the center portion of the diaphragm valve is provided. When a pressure stronger than the pressure for pushing the diaphragm valve to the secondary space side through the water supply passage hole for communicating the primary space with the secondary space and the water supply passage hole is applied from the primary space side. The first feature is that a water supply passage structure body having a spring-biased water supply passage valve for opening the water supply passage hole is attached to the. In addition to the first characteristic, the backflow prevention device for a water heater or the like according to the present invention has a second characteristic that the water supply passage valve is provided with a small hole for pressure relief.

[0006]

According to the first feature, at the time of pouring water, the water from the hot water supply passage is first introduced into the primary space inside the apparatus main body. With this, as the pressure in the primary space increases, first, the diaphragm valve, which is more easily pushed by the pressure, is pushed toward the secondary space side against the biasing spring, which causes the overflow passage port on the secondary space side. Closed. Then, as the pressure in the primary space further increases, the water supply passage valve of the water supply passage constituting body attached to the center of the diaphragm valve opens the water supply passage against the spring. As a result, water flows from the primary space to the secondary space and then to the downstream. On the secondary space side where the overflow passage opening is located, water flows after the overflow passage opening is closed.Therefore, it is possible to reliably prevent the generation of wasteful overflow water during water injection, regardless of changes in the water injection flow rate. It When a backflow is applied to the secondary space side, the water supply passage valve as well as the water supply passage are kept in the closed state, and the diaphragm valve holds the overflow passage opening in an open state, so that backflow water easily flows from the overflow passage opening. Is discharged. Since the mechanism and members for preventing backflow are integrated into the internal space of the device body,
The entire device becomes compact. Further, according to the second feature, in addition to the action of the first feature, the water supply passage valve is provided with a small hole for pressure relief, so that the residual pressure on the primary space side after completion of water injection is It escapes from the small hole to the secondary space side, whereby the diaphragm valve is quickly returned to its original position.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a vertical sectional view of an apparatus for carrying out the present invention.

The apparatus body 10 is composed of a unit in which two members 11 and 12 are integrally connected, and the inner space of the apparatus body 10 is divided into a primary space 20 and a secondary space 30 by a diaphragm valve 40. Solenoid valve dropped on the ceiling of the primary space 20
A drop port 21 that is opened and closed by 50 is provided, and a hot water supply passage hole 60 is formed so as to communicate with the drop port 21 from the side. The drop-in solenoid valve 50 is electromagnetically moved up and down by a solenoid structure 51 fitted and fixed to the ceiling of the apparatus body 10 to open and close the drop-in port 21. The hot water supply passage hole 60 is connected to an upstream hot water supply passage U from a water heater or the like.

The secondary space 30 has a device body at the lower end thereof.
An outlet hole 70 from the port 10 is provided, and an overflow passage port 81 is provided in the side wall portion.
Are formed so as to communicate with each other toward the side. Reference numeral 82 is a valve seat for opening and closing the overflow passage port 81. The outlet hole 70 is connected to the downstream hot water supply passage L.

The diaphragm valve 40 corresponds to the apparatus main body 10
It is fixed in a form sandwiched by the upper and lower members 11 and 12, and is normally biased from the secondary space 30 side by a biasing spring 41 so as to be held in the vicinity of dividing the primary space 20 and the secondary space 30 in normal times. ing. A water supply passage structure 90 is fixed to the center of the diaphragm valve 40 so as to be fitted thereto. The water supply passage structure 90 is a member for forming a water supply passage between the primary space 20 and the secondary space 30 as needed, and a water supply passage hole 92 is provided in the ceiling wall of the central tubular portion 91. A water supply passage valve 94 urged by an urging spring 93 is provided on the secondary space 30 side of the water supply passage hole 92. A small hole 95 is provided in the water supply passage valve 94. This small hole 95 is made sufficiently smaller than the water supply passage hole 92. Further, the urging force of the urging spring 93 that urges the water supply passage valve 94 from the primary space side 20 toward the water supply passage hole 92 is urged to press the diaphragm valve 40 from the secondary space side 30 to the normal position. It is made sufficiently larger than the biasing force of the biasing spring 41.

When hot water is supplied to a hot water supply device (not shown) or the like, the solenoid of the solenoid structure works, the drop solenoid valve 50 opens the drop port 21, and water passes through the drop port 21 and enters the primary space 20. be introduced. At this time, a part of the water flows down from the small holes 95 to the secondary space 30 side, but since the hole diameter is small, the water immediately fills the primary space 20 and the pressure starts to rise. Due to the pressure increase, the diaphragm valve 40, which has the smaller spring bias, is first pushed toward the secondary space 30 by the pressure from the primary space side, whereby the diaphragm valve 40 contacts the valve seat 82 of the overflow passage port 81. And press down to close the passage opening 81. Then, when the pressure on the side of the primary space 20 further rises, the water supply passage valve 94 of the water supply passage constituting body 90 is pushed down against the biasing spring 93, and the water supply passage hole 92 is opened. As a result, the passage from the primary space 20 to the secondary space 30 is opened and water flows. Since the overflow passage port 81 is sufficiently closed, air is not mixed therein. Also, no water leaks from the passage opening 81. When the stop of water supply by the water heater is instructed, the drop solenoid valve 50 is closed and the primary space 20
Water supply to the inside is stopped. The residual pressure in the primary space 20 is appropriately released as water flows out from the small hole 95 of the water supply passage valve 94 to the secondary space 30 side, whereby the pressure is released, and as a result, the diaphragm valve by the urging spring 41 is promptly released. A return of 40 to its original normal position is made. Of course, before that, the water supply passage valve 94 closes the water supply passage hole 92 by the biasing spring 93. By promptly returning the diaphragm valve 40 to the original position, the overflow passage port 81 is opened, and it is possible to promptly cope with the subsequent backflow. When there is a backflow, the small hole 95 of the water supply passage valve 94 is sufficiently above the overflow passage opening 81, and therefore does not flow back to the upstream side through the small hole 95.

[0012]

EFFECTS OF THE INVENTION The present invention has the above-described structure and operation. According to the backflow prevention device for a water heater or the like as set forth in claim 1, in principle, when water is injected, the diaphragm is provided in the secondary space having the overflow passage port. Water does not enter unless the water supply passage valve in the valve is opened, and the water supply passage valve is opened only after the overflow passage port is closed by the diaphragm valve. Therefore, it is possible to reliably prevent the generation of useless overflow water during water injection, regardless of changes in the water injection flow rate, etc.
Further, it is possible to reliably prevent air from entering from the overflow passage opening side. Further, since the mechanism and members for preventing backflow are integrated in the inner space of the apparatus body, the entire apparatus becomes compact. Further, according to the backflow prevention device for a water heater or the like according to claim 2, in addition to the effect of the configuration according to claim 1, the water supply passage valve is provided with a small hole for pressure relief, The residual pressure on the primary space side after water injection is released to the secondary space side, and the diaphragm valve can be quickly returned to the original position. This makes it possible to quickly prepare for overflow discharge with respect to the backflow.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an apparatus for carrying out the present invention.

FIG. 2 is a vertical sectional view of a device of a conventional device.

[Explanation of symbols]

 10 Main body 20 Primary space 30 Secondary space 40 Diaphragm valve 41 Energizing spring 50 Drop-in solenoid valve 60 Hot water supply passage hole 70 Outlet hole 80 Overflow hole 81 Overflow passage opening 90 Water supply passage structure 92 Water supply passage hole 93 Energizing spring 94 Water supply Passage valve 95 small hole

Claims (2)

[Claims] 1. A backflow prevention device for a water heater or the like, wherein the device body is connected as a unit in the middle of a hot water supply passage, and a backflow from the downstream side does not flow back to the upstream side of the device body. , The inner space provided in the apparatus body is partitioned by a spring-biased diaphragm valve into a primary space connected to the upstream side of the hot water supply passage and a secondary space connected to the downstream side of the hot water supply passage, and the secondary space Is provided with an overflow passage port which is closed when the spring-biased diaphragm valve is pushed to the secondary space side by the pressure of the primary space side, and the primary part is provided at the center of the diaphragm valve. A water supply passage hole for communicating the space and the secondary space, and the water supply passage when a pressure stronger than the pressure for pushing the diaphragm valve to the secondary space side through the water supply passage hole is applied from the primary space side Open a hole A backflow prevention device in a water heater or the like, characterized in that a water supply passage structure having a spring-biased water supply passage valve is attached. 2. The backflow prevention device for a water heater or the like according to claim 1, wherein the water supply passage valve is provided with a small hole for pressure relief.