JPH0345293B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a gas instantaneous water heater, particularly a gas instantaneous water heater of the type in which a calculation means of a control section calculates a necessary heat load and automatically controls combustion of a burner. Regarding water heaters.

(Prior art) This type of gas instantaneous water heater connects the water supply pipe of the water heater, the hot water pipe on the building side that connects to the water supply pipe, and the water supply pipe with a return pipe to form a circulation flow path, and When hot water is not being supplied, water is circulated through the circulation channel and kept at a set temperature or a predetermined safe temperature, and when the hot water supply equipment is used, it is immediately kept at the above temperature. It is possible to discharge hot water.

However, when using the water heater in this way,
When negative pressure occurs upstream of the water supply pipe due to a water outage or the like, water in the circulation flow path, that is, water that has once passed through the heat exchanger, may flow back upstream of the water supply pipe.
Furthermore, heating the circulating water causes volumetric expansion and increases pressure, which may affect the water supply piping (main pipe side).

Therefore, if you are going to use a water heater as described above, you should install a check valve or vacuum breaker valve at an appropriate point in the water supply system, which is made up of the water heater's water supply pipe and the building's water supply pipe connected to it. However, not all water heaters are used in the above-mentioned way to keep warm, and many do not use them in this way, so it is necessary to incorporate the above-mentioned check valve or A vacuum breaker valve cannot be installed in the water supply pipe of a water heater in advance.

Therefore, if you want to maintain the temperature, the above-mentioned check valves and vacuum breaker valves will inevitably be installed on the water supply piping side of the building at the time of construction. This increases the troublesome work for the constructor, such as complicated piping work during construction to incorporate it into the piping of the circulation flow path.

(Problems to be Solved by the Invention) The present invention has been made in view of the current situation, and its purpose is to provide a gas circulation path that enables a heat-retaining circulation flow path structure without complicating piping work. The purpose is to provide an instant water heater.

(Means for Solving the Problems) In order to achieve the above object, the gas instantaneous water heater of the present invention includes a main body of the water heater, a water supply pipe of the water heater main body, a water supply pipe of the water heater main body, and a water supply pipe of the water heater main body. It consists of a water supply pipe, a hot water supply pipe, and a return unit equipped with a return pipe connecting pipe connected to the water supply pipe, and the return pipe of the return unit is equipped with a pump, and the return pipe of the water supply pipe is connected to the return pipe. A check valve and a vacuum breaker valve are installed in advance on the upstream side of the pipe connection.

(Function) For the gas instantaneous water heater configured as above, one end of the return unit's water supply pipe and hot water supply pipe is connected to the water supply pipe and hot water supply pipe of the water heater body, and the other end is connected to the building's water supply pipe. By connecting piping and hot water supply piping, and connecting the return pipe branched from the hot water supply piping to the return pipe communication pipe of the return unit, a check valve, vacuum breaker valve, and pump are prepared and incorporated into the piping. Even if this is not done, a heat-retaining circulation flow path with no fear of backflow to the upstream side of the water supply pipe can be constructed.

In addition, the return unit can be removed from the main body of the water heater to accommodate sites where there is no need to construct a heat-retaining circulation flow path.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

A in the figure is a water heater, which consists of a water heater body a and a return unit b that is detachably connected to the lower part of the water heater body a, and the functional parts are housed in the main body casing 7 and return unit casing 8, respectively. are doing.

The water heater body a has two heat exchangers for one heat exchanger 9.
By burning the gas supplied through the gas pipe 20 in both or one of the burners 10 and 11, the water supplied through the water supply pipe 2 is transferred to the heat exchanger 9. It is heated and flows into the hot water supply pipe 12, and the burners 10 and 1 mentioned above
1 is controlled by the control section 1 according to the required heat load.

That is, the water supply pipe 2 is provided with a water amount sensor 13 and an incoming water temperature sensor 14, and the hot water supply pipe 12 is provided with an outlet water temperature sensor 15. The temperature of the hot water that exits the exchanger 9 and flows into the hot water pipe 12 is detected, and the data is sent to the control unit 1. The control unit 1 is provided separately from these data and the water heater A. The required heat load is calculated based on the set temperature etc. set by the controller B which is electrically connected to the controller B, and the burners 10 and 11 to be used and the heat amount control method are selected based on the calculated value. The proportional control valves 16, 17 and solenoid valves 18, 19 are controlled.

The burners 10 and 11 are selected by opening the valves 18 and 19.

In addition, as a heat amount control method, the proportional control valve 16,
Proportional control valve 16, 1 is a method of changing the amount of heat by varying the opening degree of 17 to change the amount of gas supplied.
One of the methods is to keep the opening degree of valve 7 constant, repeat opening and closing of solenoid valves 18 and 19, and change the amount of heat by changing the length of the opening/closing cycle and the ratio of valve opening time to valve opening time. selected.

On the other hand, the return unit b has a water supply pipe 2', a hot water supply pipe 12', and a gas pipe 20', which are connected to the water supply pipe 2, the hot water supply pipe 12, and the gas pipe 20, respectively, of the water heater main body a. ', hot water pipe 12', gas pipe 2
0' have ends protruding from the bottom of the return unit casing 8, and connection ports 25, 26, 27 for connecting the building's water supply pipe 21, hot water supply pipe 22, and gas pipe 24 are provided at these projecting ends. .

A return pipe connecting pipe 4 is connected to the water supply pipe 2' in the middle thereof, and a check valve 5 and a vacuum breaker valve 6 are integrally built in the upstream side of the connection part of the return pipe connecting pipe 4 to reduce the pressure. Attach valve 28.

Also, a check valve 29 is provided at the connection port 25 of the water supply pipe 2'.
are provided in one piece.

On the other hand, the end of the return pipe communication pipe 4 is made to protrude from the bottom of the return unit casing 8, and a connection port 31 for connecting the return pipe 30 is provided in this part.

Further, the return pipe communication pipe 4 is equipped with a pump 3 in the middle thereof, and is equipped with a water flow switch 32 and a check valve 33 with a drain plug on the upstream side of the pump 3. The return unit b may be connected to the water heater main body a in advance at the time of factory shipment, or may be connected to the water heater main body a at the construction site.

Thus, such a gas instantaneous water heater connects the water heater main body a and the return unit b, and the return unit b has a connection port 25 at the end of the water supply pipe 2' and a connection port 26 at the end of the water supply pipe 12'. By connecting the water supply piping 21 and the hot water supply piping 22 of the building, respectively, and connecting the return pipe 30 branched from the hot water supply piping 22 to the connection port 31 of the return pipe communication pipe 4, a circulation flow path 34 is formed.

Therefore, if the pump 3 is driven when the hot water supply equipment 35 provided in the hot water supply piping 22 is not in use, water circulates in the circulation channel 34, and this circulating water is controlled in the same way as when hot water is supplied. The burners 10 and 11 controlled by the unit 1 maintain the temperature at a set temperature or a predetermined temperature determined separately.

In addition, the return pipe 30 is not branched from the hot water supply pipe 22, and the connection port 3 of the return pipe communication pipe connection part 4 is
If 1 is closed with a blind lid, it can be used as a general water heater without a heat retention function.

(Effects) Since the present invention is constructed as described above, it produces the following effects.

A gas instantaneous water heater is equipped with a main body of the water heater, a water supply pipe of the main body of the water heater, a water supply pipe connected to each of the hot water pipes, a water supply pipe connected to the water supply pipe, and a return pipe connecting pipe connected to the water supply pipe. The return unit is equipped with a pump, and a check valve and a vacuum breaker valve are installed upstream of the return pipe connection of the water supply pipe, so that no hot water can be supplied. When attempting to perform a heat-retaining operation in which the water in the pipes is circulated and maintained at a set temperature or a predetermined safe temperature, one end of the water supply pipe or hot water pipe of the return unit must be closed. Connect to the water supply pipe of the water heater main body, the hot water supply pipe, and connect the building's water supply pipe to the other end.
By simply connecting the hot water supply piping and connecting the return pipe branched from the hot water supply piping to the return pipe connection pipe of the return unit, you can create a heat-retaining circulation flow path with no risk of backflow to the upstream side of the water supply pipe. During construction, there is no need to install a check valve or vacuum breaker valve in the water supply piping, or to install a pump in the return pipe.

Therefore, construction is easy.

Furthermore, there is no need for the contractor to prepare check valves, vacuum breaker valves, pumps, etc.

By connecting the return unit to the main body of the water heater at the time of shipment from the factory, the above-mentioned on-site construction can be further facilitated.

If you do not need to be able to keep warm, you can do this by not using the return unit, and you will need to prepare two types of water heaters: one for keep warm operation and one for non-warm operation. do not have.

[Brief explanation of drawings]

The drawing is a schematic diagram of a gas instantaneous water heater showing an embodiment of the present invention. A: water heater, a: water heater main body, b: return unit, 1: control section, 2: water supply pipe of water heater main body,
2': Return unit water supply pipe, 3: Pump,
4: Return pipe communication pipe, 5: Check valve, 6: Vacuum break valve, 12: Water supply pipe of the main body of the water heater, 12': Water supply pipe of the return unit.

Claims (1)

[Claims] 1 A gas instantaneous water heater that controls the combustion of the burner based on the required heat load calculated by the calculation means of the control section, which includes a main body of the water heater, a water heater that can be detachably attached to the main body of the water heater, and a water supply for the main body of the water heater. The return unit is equipped with a return pipe connected to the water supply pipe, a hot water pipe, and a return pipe connected to the water supply pipe, and the return pipe of the return unit is equipped with a pump, A gas instantaneous water heater characterized by being equipped with a check valve and a vacuum breaker valve on the upstream side of the return pipe connecting part.