JPS6314267B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an instantaneous gas water heater, a so-called gas proportional gas water heater, in which the temperature of hot water is controlled by the amount of gas.

(Prior Art) In a conventional gas water heater of this kind, water supplied from the water supply pipe first flows to the heat exchanger by opening the hot water side of a water supply equipment, such as a faucet, installed at the end of the water supply pipe. The water is heated here and flows directly to the hot water side of the hot water supply equipment via the hot water supply pipe.

Therefore, in the above-mentioned conventional water heater, if it has been a while since the last time hot water was used, the water in the pipe is cold, and even if the hot water side of the faucet is opened, the rising time of the hot water or There is a time period for the hot water that leaves the heat exchanger to flow through the hot water supply pipes to the faucet, so there is an inconvenience that the hot water does not come out immediately, and there is a time when the hot water flows from the faucet until the hot water comes out. There were inconveniences and uneconomical consequences, such as the discharged water being thrown away.

In addition, if there is a short period of time after stopping the use of hot water and before using it again, the temperature of the heat exchanger will rise after the previous stop of use, and the temperature of the hot water will rise rapidly when starting to use it again. There is a problem with boiling water after it comes out.

(Problem to be Solved by the Invention) The problem to be solved by the present invention is that when hot water supply is stopped, the water in the piping is circulated through the heat exchanger of the water heater, and this circulating water is heated and set at all times. The temperature is maintained at a certain temperature, and when hot water is supplied, hot water maintained at this set temperature is first supplied.

(Means for Solving the Problems) The technical means acquired by the present invention in order to solve the above problems is a gas instantaneous water heater that controls the water temperature by adjusting the amount of gas. In a water heater that uses inlet water temperature and set temperature as elements for gas volume control, a return pipe is branched from the hot water supply pipe, and the return pipe is connected to the upstream side of a water flow sensor provided in the water supply pipe for detecting the water flow. The return pipe is connected to the hot water supply pipe, and the return pipe is equipped with a pump and a check valve.

(Function) According to the above-mentioned technical means of the present invention, when hot water supply is stopped, the water in the annular pipe consisting of the water supply pipe, the heat exchanger, the hot water supply pipe and the return pipe is pumped by the operation of the pump. The circulating water is heated by the amount of gas calculated based on the flow rate, the temperature of water entering the heat exchanger, and a preset temperature, and while maintaining the set temperature, You can prepare for the start of hot water supply.

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

In the figure, reference numeral 1 denotes a water heater, in which gas supplied through gas piping 8 is combusted in burner 9, water supplied through water supply pipe 2 is heated in heat exchanger 10, and hot water supply pipe 4 is heated. The hot water then flows to the primary side of the hot water side valve 12 of the hot water supply device 11, such as a faucet.

Then, the gas pipe 8 has a first pipe, a first pipe,
Second electromagnetic valves 13, 14, a governor 15 and a proportional valve 16 are provided.

On the other hand, in the water supply pipe 2, a water flow sensor 3 and an incoming water temperature sensor 17 are sequentially installed in the hot water supply pipe 4 from the upstream side.
A hot water temperature sensor 18 is provided at each of the hot water outlets.

Further, the hot water supply pipe 4 branches a return pipe 5 at a midpoint thereof, preferably near the hot water supply appliance 11, and connects the other end of the return pipe 5 to the water supply pipe 2 on the upstream side of the water flow sensor 3. .

The return pipe 5 is provided with a pump 6 that sucks water from the hot water supply pipe 4 side and flows it into the water supply pipe 2, and also draws water from the water supply pipe 2 side to the hot water pipe 4 side via the return pipe 5. A check valve 7 is provided to prevent flow.

The pump 6 draws the hot water flowing through the hot water supply pipe 4 into the return pipe 5 when hot water is being supplied to the hot water supply equipment 11, and the flow rate is set to 2.
Install one with a small capacity of about / minute.

The first and second electromagnetic valves 13 and 14 of the gas pipe 8, the proportional valve 16, the water flow sensor 3 of the water supply pipe 2, the inlet water temperature sensor 17, and the outlet water temperature sensor 18 of the hot water supply pipe 4
The pumps 6 and return pipes 5 are electrically connected to the controller 19, the water flow sensor 3 detects the amount of water flowing through the water supply pipe 2 and outputs a signal A, and the incoming water temperature sensor 17 detects the water supply pipe 2. A signal B is generated by detecting the temperature of water entering the heat exchanger 10 through the
In addition, the outlet hot water temperature sensor 18 detects the outlet hot water temperature from the heat exchanger 10 and sends a signal C to the controller 19, respectively.

The controller 19 includes an operation switch 20, a temperature setting section 21, and a calculation section (not shown), and when the operation switch 20 is turned on, it sends a signal D to the pump 6 to rotate the pump 6, and at the same time turns on the solenoid valve. Send signal E to solenoid valves 13 and 14,
14 to open the burner 9 and ignite the burner 9. At the same time, the calculation unit calculates the amount of water detected by the water amount sensor 3, the inlet water temperature detected by the inlet water temperature sensor 17, the set temperature set in the temperature setting unit 21, and the heat Calculating the required gas amount based on the thermal efficiency of the exchanger 10,
Furthermore, the total required gas amount is determined by adding the outlet hot water temperature detected by the outlet hot water temperature sensor 18, the above-mentioned set temperature, and the gas amount calculated by the proportional gain to this required gas amount. Signal F
is sent to change the opening degree of the proportional valve 16, and the amount of gas supplied to the burner 9 is controlled to the total required gas amount calculated by the calculation section.

In addition, 22 in the figure indicates the setting when the amount of hot water being supplied is large and the amount of gas exceeding the maximum capacity of the water heater 1 is required to dispense hot water at the set temperature, and the hot water temperature cannot be controlled by the amount of gas. This is a water flow valve that restricts the amount of water supplied so as not to flow hot water exceeding the limit water flow at the temperature, and is connected to the controller 19 and operates based on the signal G from the controller 19.

This water flow valve 22 can be replaced with a constant flow valve, and in that case, electrical connection between the constant flow valve and the controller 19 is not required.

First, when the operation switch 20 of the controller 19 is turned on with the hot water side valve 12 of the water heater 11 closed, the hot water temperature sensor 18 detects that the water temperature in that part has not reached the set temperature. At the same time, the pump 6 starts rotating, the solenoid valves 13 and 14 open, and the burner 9 starts combustion.

Therefore, water in the piping is returned to the water supply pipe 2 from the water supply pipe 2 by the operation of the pump 6, via the heat exchanger 10, the hot water supply pipe 4, and the return pipe 5 on the upstream side of the water flow sensor 3. It circulates and is heated as it passes through the heat exchanger 10.

At this time, the combustion in the burner 9 is controlled by the controller 19 by calculating the gas input amount based on the above calculation, so that the circulating water is boiled up to the set temperature and maintained at the set temperature.

Next, when the hot water side valve 12 of the water heater 11 is opened, the hot water that has already been boiled to the set temperature in the piping is supplied to the hot water heater 11, and then the water newly supplied from the water supply pipe 2 is supplied. is heated to a set temperature and supplied.

In addition, when using hot water with the water heater 11, the amount of water,
Although the temperature of the incoming water naturally changes from that during the above-mentioned circulating flow, that is, when hot water is not used, the amount of gas input is calculated in the controller 19 and continues to be optimally controlled via the proportional valve 16.
Continues to reliably supply hot water at the set temperature.

At this time, the pump 6 continues to operate, but because its capacity is small, it draws the hot water from the hot water supply pipe 4 into the return pipe 5 and prevents the supply of sufficient hot water to the hot water supply equipment 11. Never.

Furthermore, even if the amount of hot water supplied greatly exceeds the capacity of the pump 6 due to, for example, fully opening the hot water side of the water heater 11, the return pipe 5 is provided with a check valve 7 on the downstream side of the pump 6. There is no fear that water will flow directly into the water supply pipe 2 from the water supply pipe 2 through the return pipe 5 against the operation of the pump 6.

Then, if the hot water side valve 12 of the water heater 11 is closed, the supply of new water to the water heater 1 is stopped.
The hot water in the piping is circulated again and maintained at the set temperature, waiting for the next use of the water heater 11.

In the above-mentioned embodiment, the water heater that controls the water temperature by the amount of gas was explained as being of the type that is controlled by adding feedback control to the feed-forward control. It is also optional to only perform the following.

(Effects) Since the present invention has the above configuration, it has the following advantages.

(1) The water in the pipes is always boiled to the set temperature, so you can use the hot water immediately by opening the hot water valve on the water heater.

Therefore, the ease of use is improved, and there is no need to throw away the discharged water until the hot water comes out, unlike in the conventional case, and it is economical.

(2) Even if you stop using hot water in the water heater, hot water continues to flow through the heat exchanger due to the pump, so after-boiling does not occur, and when you open the hot water valve on the water heater, the temperature will be much lower than the set temperature. There is no risk of burns from hot water being discharged.

(3) In water heaters that use water volume, incoming water temperature, and set temperature as elements of gas volume control, that is, water heaters that employ feed-forward control, the water in the piping is circulated when hot water supply is stopped, and the circulating water is Since the heating is maintained at the set temperature, hunting can be reduced even though a small amount of water is circulated and heated, and when the hot water side of the hot water heater is opened, There are no problems such as hot water coming out at a high temperature or hot water at a temperature significantly lower than the set temperature, and hot water at the set temperature can be supplied immediately and always at the time of hot water supply.

(4) A check valve was installed in the return pipe on the downstream side of the pump to prevent water from flowing through the return pipe from the water supply pipe to the hot water supply pipe, so even if the amount of hot water supplied was increased, the return pipe There is no risk of water flowing into the hot water supply pipe through the pipe and lowering the temperature of the hot water, and hot water at the set temperature is reliably supplied to the hot water supply equipment.

[Brief explanation of the drawing]

The drawing is a schematic diagram of a gas water heater showing an embodiment of the present invention. 1...Water heater, 2...Water supply pipe, 3...Water flow sensor, 4...Hot water supply pipe, 5...Return pipe, 6...
...Pump, 7...Check valve.

Claims (1)

[Claims] 1. In a gas instantaneous water heater that controls the water temperature by adjusting the gas amount, and in which at least the water amount, inlet water temperature, and set temperature are the elements of gas amount control, the return pipe is branched from the hot water supply pipe. The return pipe is connected to the water supply pipe on the upstream side of the water flow sensor provided in the water supply pipe for detecting the water volume, and the return pipe is provided with a pump and a check valve. gas water heater.