JPH0796972B2 - Backflow prevention device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a backflow prevention device provided in a hot water supply circuit which is a tap water circuit, which is connected to a bath circuit which is a miscellaneous water circuit such as a bath with a water heater. Is.

(Prior Art and Problems) Conventionally, in a system that connects a bath circuit that is a miscellaneous water circuit and a hot water supply circuit that is a clean water circuit, it is necessary to prevent water from mixing into the clean water circuit from the miscellaneous water circuit. As the backflow prevention device, the present applicant has previously proposed JP-A-3-251656. This is provided with a check valve and a backflow prevention chamber in the connection circuit between the miscellaneous water circuit and the water supply circuit, and below the backflow prevention chamber, an atmospheric water storage hopper that can store water in the backflow prevention chamber is provided. A backflow prevention chamber opening / closing valve is provided between the storage hopper and the backflow prevention chamber, which closes when water pressure is applied to the backflow prevention chamber and opens when the water flow pressure disappears.

This backflow prevention device has a water reservoir hopper that opens to the atmosphere in a branch water channel that branches from the backflow prevention chamber of the hot water supply circuit.When hot water is supplied to the bathtub, the backflow prevention chamber opening / closing valve serves as the water reservoir hopper and the hot water supply passage. Although it closes to the prevention chamber, if a bath with a water heater equipped with a backflow prevention device is installed above a certain height above the bathtub, the backflow prevention chamber will have a negative pressure when the amount of hot water supply is small. As a result, the backflow prevention chamber opening / closing valve has poor sealing performance, and hot water leaks into the water storage hopper, and hot water overflows from the atmosphere communication port that also serves as the overflow port of the water storage hopper.

The present invention solves the above-mentioned problems and detects water leakage and discharges the hot water leaking into the water reservoir hopper to the miscellaneous water circuit so that the overflow port does not overflow.

(Means for Solving the Problems) The present invention is configured as follows to achieve the above object.

That is, in a hot water supply circuit that connects the clean water circuit and the miscellaneous water circuit with a check valve and a backflow prevention chamber, an atmosphere open water storage hopper that stores water in the backflow prevention chamber is provided below the backflow prevention chamber. Provided between the water storage hopper and the backflow prevention chamber is a backflow prevention chamber opening / closing valve that closes when water pressure is applied to the backflow prevention chamber and opens when water pressure is lost, and the water is stored in the water storage hopper. A water level detector for detecting the water level of the reservoir hopper is installed, and a solenoid valve for drainage is installed in the branch water passage from the drain port provided at the bottom of the water reservoir hopper to the hot water supply circuit to ensure that a certain amount of hot water is stored in the water reservoir hopper. When it leaks, the water level is detected and the electromagnetic valve for drainage is opened to drain the hot water in the water reservoir hopper into the miscellaneous water circuit.

(Function) When hot water is supplied to the bathtub, under a condition where the amount of hot water supplied is small, the backflow prevention chamber becomes negative pressure, the sealing performance of the backflow prevention chamber opening / closing valve deteriorates, and hot water leaks into the water reservoir hopper. If more than a set amount of hot water leaks, the water level detector detects this water level and opens the drainage solenoid valve to discharge the hot water in the water reservoir hopper from the branch water passage to the miscellaneous water circuit through the hot water supply circuit and then discharge it. After a certain time, the solenoid valve for drainage is closed. By controlling so that this operation is repeated, overflow from the overflow port is prevented.

(Embodiment) FIG. 1 is a schematic configuration diagram of a bathtub with a water heater equipped with the backflow prevention device of the present invention, and FIG. 2 is a cross-sectional view of a main part of the backflow prevention device showing an embodiment of the present invention. .

(1) is a bath circuit connected with a bath heat exchanger (2) and connected to a bath (3), including a three-way valve (4) and a circulation pump (5).
Is provided. (6) is a hot water supply circuit connected to the hot water supply heat exchanger (7), which is connected to the three-way valve (4) provided in the bath circuit (1) via the backflow prevention device (8) to connect to the bathtub (3). It is designed so that hot water can be supplied.

The backflow prevention device (8) is provided with a drop solenoid valve (9), a check valve (10) and a backflow prevention chamber (11), and the check valve (10) is provided in the backflow prevention chamber (11) at the top. A hopper valve body (13) integrally provided with a backflow prevention chamber opening / closing valve (12) in the lower part is housed, and the hopper valve body (13) is always provided with an inlet of the backflow prevention chamber (11) by a spring (14). It is urged to close (15).

An outlet (16) to which the hot water supply circuit (6) is connected is provided on the side of the backflow prevention chamber (11), and a second check valve (17) is provided subsequent to the outlet (16). The hot water supply circuit (6) is connected to the three-way valve (4) to supply hot water to the bathtub (3) via the bath circuit (1).

A water storage hopper (19) having an overflow port (18) for opening to the atmosphere is formed on the side surface below the backflow prevention chamber (11), and is provided between the backflow prevention chamber (11) and the water storage hopper (19). A drain port (20) for draining the remaining hot water of the backflow prevention chamber (11) into the hopper (19) is provided in the container, and the backflow prevention chamber opening / closing valve (12) is used for opening and closing. The volume below the overflow port (18) of the water storage hopper (19) is made slightly larger than the volume of the backflow prevention chamber (11), and a water level detector such as an electrode level switch or thermistor is placed at an appropriate position on its side wall. (21) is provided.

In addition, a drainage port (23) connected to the branch waterway (22) is provided on the bottom surface of the water storage hopper (19), and a drainage solenoid valve (24) is provided below it to provide the branch waterway (22). Open and close. The end of the branch waterway (22) is connected to the end of the hot water supply circuit (6) and connected to the bath circuit (1) via the three-way valve (4), and when the drainage solenoid valve (24) is opened, the water reservoir hopper is opened. The hot water in (19) can be discharged to the bath circuit (1) side through the three-way valve (4).

Therefore, in the check valve (8), the solenoid valve (9), the check valve (10), the check chamber (11), and the second check valve (17) reach the three-way valve (4). The hot water supply circuit (6) and the backflow prevention chamber (11) branch off from the backflow prevention chamber opening / closing valve (12),
A water reservoir hopper (19), a branch circuit (22) that reaches the three-way valve (4) via the drainage solenoid valve (24) are configured.

If the drop solenoid valve (9) is opened,
Due to the flow of water, the check valve (10) receives water pressure and pushes the hopper valve element (13) downward to open it, and the check valve (1) opens.
2) is closed.

The backflow prevention chamber (11) is filled with the inflowing hot water, and the second
The check valve (17) is also opened, and the hot water supply circuit (6) to the three-way valve (4)
After that, hot water is supplied to the bath circuit (1) side.

If the bath kettle is installed above a certain height above the bathtub, the backflow prevention chamber (11) will become negative pressure and the sealing performance of the backflow prevention chamber opening / closing valve (12) will deteriorate if the amount of hot water supply is small. Hot water during hot water supply may leak into the water reservoir hopper (19).

In this case, when the hot water leaks more than a certain amount, the water level detector (21) detects this and activates the drainage solenoid valve (24).
The hot water accumulated in the water reservoir hopper (19) is discharged to the bath circuit (1). When the discharge is completed, the water level detector (21) is turned off and the drainage solenoid valve (24) is closed for a certain period of time. By repeating this operation, control is performed to prevent overflow from the overflow port (18).

When hot water supply is completed and the drop-in solenoid valve (9) is closed, the water pressure on the check valve (10) and the second check valve (17) disappears, and the check valves (10), (17) ) Is closed by spring pressure, and the backflow prevention chamber opening / closing valve (12) is opened and the backflow prevention chamber (1
The residual water of 1) flows into the water storage hopper (19), and the backflow prevention chamber (11) is replaced with the air flowing in from the overflow port (18). Therefore, the primary side upstream of the depression solenoid valve (9) and the secondary side downstream of the second check valve (17) are completely cut off. Thereafter, the drainage solenoid valve (24) is opened, the circulation pump (5) is operated, and the residual water in the water reservoir hopper (19) is discharged to the secondary side.

Further, in the steady state, the depression solenoid valve (9) is closed, and the check valve (10) and the second check valve (17) are also closed by springs.
Check valve (1) that is integrated with the check valve (10)
2) Open the backflow prevention chamber (11) and the reservoir hopper (1
9) The inside is filled with air.

(Effects of the Invention) As described above, the present invention is provided with the water level detector in the water storage hopper of the backflow prevention device, and when water is accumulated above a certain level during hot water supply, the electromagnetic valve for drainage is opened to discharge the water to the miscellaneous water circuit As a result, it is possible to prevent water from overflowing from the overflow port regardless of the construction conditions.

Further, the conventional backflow prevention device can be used only by adding a simple water level detector, and the backflow prevention device can be installed free.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a bathtub with a water heater using the backflow prevention device of the present invention, and FIG. 2 is a cross-sectional view of a main part of the backflow prevention device showing an embodiment of the present invention. (1) …… Bath circuit (6) …… Hot water supply circuit (8) …… Backflow prevention device (10) …… Check valve (11) …… Backflow prevention chamber (12) …… Backflow prevention chamber opening / closing valve (19) ) …… Water reservoir hopper (21) …… Water level detector (22) …… Branch channel (23) …… Drain port (24) …… Drainage solenoid valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Matsui 32 Akashi-cho, Chuo-ku, Kobe, Hyogo Pref. Hideaki Tazawa, Examiner, Noritsu Co., Ltd. (56) Reference JP-A-2-37226 (JP, A)

Claims (1)

[Claims] 1. A hot water supply circuit connecting a tap water circuit and a miscellaneous water circuit, wherein a check valve and a backflow prevention chamber are provided, and the water is open to the atmosphere below the backflow prevention chamber for accumulating water in the backflow prevention chamber. A backflow prevention chamber opening / closing valve is provided between the water storage hopper and the backflow prevention chamber, which closes when water pressure is applied to the backflow prevention chamber and opens when the water flow pressure disappears. A water level detector for detecting the water level of the water storage hopper is installed in the water storage hopper, and a drainage solenoid valve is installed in a branch water passage from the drain port provided at the bottom of the water storage hopper to the hot water supply circuit to keep the water storage hopper constant. A backflow prevention device characterized in that when the hot water leaks, the water level is detected and the electromagnetic valve for drainage is opened to drain the hot water in the water reservoir hopper to the miscellaneous water circuit.