JPH0160746B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a gas instantaneous water heater.

(Background of the Invention) 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 device, 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 hot water rise time or There is a time period for the hot water that comes out of the heat exchanger to flow through the hot water supply pipes to the faucet, which can be inconvenient because the hot water does not come out immediately, or the faucet may close before the hot water comes out. Inconveniences such as the discharged water being thrown away,
There was an uneconomic situation.

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.

Therefore, in order to solve the above-mentioned problem, the applicant of the present application proposed a return pipe branched from the hot water supply pipe in front of the water flow sensor installed in the water supply pipe in a gas instantaneous water heater that controls the hot water temperature by the amount of gas. By connecting the return line and providing a pump in the return line,
When there is no hot water coming out of the water heater, the water in the annular pipe line consisting of the water supply pipe, heat exchanger, hot water supply pipe and return pipe is circulated and the circulating water is constantly heated and maintained at a set temperature. I have already filed an application for a water heater designed to do this. (Japanese Patent Application No. 59-90707) The above-mentioned Japanese Patent Application No. 59-90707 has a structure in which the pump continues to operate even when hot water is being supplied from the water heater. (Of course, a pump with a small capacity is used to draw the hot water flowing through the hot water supply pipe into the return pipe when hot water is dispensed from the water heater, so as not to interfere with the supply of hot water to the water heater.) There is no need to operate the pump when you are dispensing hot water.

Therefore, as in the case of the above-mentioned application, keeping the pump running while dispensing hot water from the water heater not only wastes electricity but is also undesirable in terms of the durability of the pump. be.

(Problems to be Solved by the Invention) A problem to be solved by the present invention is to stop the operation of the pump when hot water is being drawn from the water heater.

(Means for solving the problem) The technical means taken by the present invention to solve the above problem is a gas instantaneous water heater that calculates the required amount of heat and automatically controls the combustion of the burner. A return pipe branched from the pipe is connected to the water supply pipe, and a pump is provided in the return pipe, and the pipe is in an annular shape consisting of the water supply pipe, the heat exchanger, the hot water supply pipe, and the return pipe. In a water heater that circulates and flows water to maintain it at a set temperature, the calculated required amount of heat is greater than or equal to the maximum amount of heat expected to be required to boil the circulating water to the set temperature and maintain it at the set temperature. When this value is exceeded, the pump operation is stopped.

(Function) For example, if the pump capacity is 2/min, the amount of heat required to boil water at 5°C to the set temperature of 60°C is (60°C - 5°C) x 2
/min=110Kcal/min.

Also, if the water temperature drops to 55℃ after it has been heated to the set temperature and is kept warm, the amount of heat required to return it to the set temperature is:
(60℃−55℃)×2/min=10Kcal/min.

In other words, assuming that the water temperature in winter is 5℃, the maximum amount of heat required to keep warm is approximately 110Kcal/min, and even taking into account piping conditions and the case that the water temperature drops over time, it is 150Kcal. /minute is enough.

On the other hand, when hot water is dispensed from a hot water heater, the amount of hot water dispensed is 2
There are almost no cases where the amount is as small as / minute.

Even if the amount of hot water dispensed is very small and the amount of hot water is 3/min, in order to boil water at 5℃ to 60℃ and dispense hot water (60
℃ - 5℃) x 3/min = 165 Kcal/min, which requires a larger amount of heat than the above 150 Kcal/min.

That is, if the calculated required amount of heat is a predetermined amount of heat that is greater than the expected maximum amount of heat required for keeping warm, in the above case 150 Kcal/min or more, hot water is being dispensed from the water heater.

Therefore, in the present invention, the operation of the pump is stopped when the calculated required heat amount exceeds a predetermined amount of heat that is higher than the expected maximum amount of heat required for keeping warm. can stop pump operation.

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

A in the figure is a water heater, in which gas supplied through gas piping 7 is combusted in burner 1, water supplied through water supply pipe 4 is heated in heat exchanger 6, and hot water supply pipe 2 is heated. The water then flows to the water heater 8.

In addition, this water heater A connects a return pipe 3 from the hot water supply pipe 2 to a midway part of the water supply pipe 4 as close as possible to the hot water supply equipment 8, and a pump 5 is provided in the return pipe 3. When hot water is not being discharged from the hot water supply equipment 8, the water in the pipe is circulated through the annular pipe line constituted by the water supply pipe line 4, the heat exchanger 6, the hot water supply pipe line 2, and the return pipe line 3. It's summery. The pump 5 used has a small capacity of about 2/min.

The gas pipe 7 is equipped with a solenoid valve 9, a solenoid valve 10, and a governor 11 in order from the upstream side, and the water supply pipe 4 is equipped with a water flow sensor 12 and an inlet water temperature sensor 13 in order from the upstream side. are each provided with a hot water temperature sensor 14, and the water flow sensor 1
2 is arranged downstream of the connection part of the return pipe 3 of the water supply pipe 4.

Above original solenoid valve 9, solenoid valve 10, water level sensor 1
2. The incoming water temperature sensor 13, the outgoing water temperature sensor 14, and the pump 5 are electrically connected to the controller 15, respectively.

The controller 15 is arranged in the machine stand of the water heater A or in the control box 16, and is configured to rotate the pump 5 and open the solenoid valve 9 when the operation switch 17 of the control box 16 is turned ON. has been done.

The controller 15 also includes a water amount sensor 1.
2, the inlet water temperature detected by the inlet water temperature sensor 13, the set temperature set by the temperature setting section 18 of the control box 16, and the outlet water temperature sensor 1.
4 calculates the required amount of heat based on predetermined factors such as the detected hot water temperature, the thermal efficiency of the heat exchanger 6, and the proportional gain, and opens and closes the solenoid valve 10 at intervals and times according to the calculated required amount of heat. The configuration is such that the operation of the pump 5 is temporarily stopped when the required amount of heat exceeds a predetermined value.

The above predetermined value is an appropriate value with a slight margin for the maximum amount of heat expected to be required to boil the circulating hot water (water) to the set temperature and maintain it at the set temperature, for example, 150Kcal/ Set to minutes.

Although not shown, there is an igniter near the burner 1 that discharges electricity in synchronization with the opening of the electromagnetic valve 11, or ignites when the operating switch 17 is turned ON and extinguished when turned OFF. Of course, a pilot burner for a pilot flame is provided.

Therefore, when the water supply temperature 8 is closed,
When the operation switch 17 of the control box 16 is turned "ON", the solenoid valve 9 opens and the pump 5 starts rotating, pumping water from the water supply pipe 4 to the heat exchanger 6, the hot water supply pipe 2, and the return pipe. The water is circulated through channel 3 and returned to the water supply pipe 4 before the water flow sensor 12, and at the same time, the controller 15 calculates the amount of heat necessary to boil the circulating water to the set temperature. The solenoid valve 10 is opened and closed at intervals and times according to the following.

Therefore, the burner 1 burns intermittently at intervals and times according to the calculated required amount of heat to heat the circulating water.

At this time, the intermittent combustion of the burner 1 is controlled by the controller 15 based on the ratio of the time when the fire is on and the time when the fire is off based on the above calculation, so the circulating water is boiled to the set temperature. And the temperature is maintained at the set temperature.

Next, when you open the water heater 8, the hot water that has already been heated to the set temperature in the piping will be poured into the water heater 8.
Then, water newly supplied from the water supply pipe 4 is heated to a set temperature and then supplied.

At this time, the flow rate of hot water from the hot water supply equipment 8 will naturally be higher than the circulating water flow rate, that is, 2/min, and the flow rate flowing through the water supply pipe 4, heat exchanger 6, and hot water supply pipe 2 will also increase, but the required amount will be increased accordingly. The amount of heat is automatically calculated by the controller 15, and the intermittent combustion of the burner 1 is optimally controlled based on the calculated required amount of heat, so hot water at the set temperature is reliably continuously supplied.

Furthermore, since the required amount of heat calculated above naturally greatly exceeds the maximum amount of heat required for heat retention and exceeds the predetermined value set above, for example, 150 Kcal/min, the controller 15 stops the operation of the pump 5. .

Then, when the water heater 8 is closed, the supply of new water to the water heater A is stopped.

Then, the required amount of heat calculated by the controller 15 naturally decreases, and the amount of heat calculated by the controller 15 decreases to the predetermined value (for example,
150Kcal/min).

Therefore, the pump 5 restarts its operation, and the hot water in the piping is circulated again and maintained at the set temperature, waiting for the next use of the water heater 8.

In the above explanation, we have described a water heater that uses a burner to burn intermittently and controls the water temperature by the ratio of the combustion time to the extinguishing time. Furthermore, it is also possible to use a combination of both of the above methods.

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

(1) When hot water is being drawn from the hot water supply equipment and there is no need to circulate the hot water, the pump will stop operating.
Power is not wasted, energy is saved, and the life of the pump is extended.

[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, 1... Burner, 2... Hot water supply pipe, 3... Return pipe, 4... Water supply pipe, 5... Pump, 6... Heat exchanger.

Claims (1)

[Claims] 1 It is a gas instantaneous water heater that automatically controls the combustion of the burner by calculating the required amount of heat, and a return pipe branched from the hot water supply pipe is connected to the water supply pipe, and a pump is connected to the return pipe. installation, water supply pipes,
In a water heater that circulates water in an annular pipe consisting of a heat exchanger, a hot water supply pipe, and a return pipe to maintain the temperature at a set temperature, the required amount of heat calculated above boils the circulating water to the set temperature. 1. A gas instantaneous water heater, characterized in that the operation of the pump is stopped when a predetermined value exceeding the maximum amount of heat expected to be required to raise and maintain the temperature at a set temperature is exceeded.