JPH0531453Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a gas instantaneous water heater, and particularly to a pump protection device for a gas instantaneous water heater equipped with a heat retention function.

(Prior art) A conventional gas instantaneous water heater with a heat retention function connects the midway point of the hot water supply pipe and the water supply pipe with a return pipe.
The water supply pipe, heat exchanger, hot water supply pipe, and return pipe form an annular circulation pipe, and a flow rate sensor and a temperature sensor are installed at appropriate locations in this circulation pipe, and a pump is installed in the return pipe in the circulation pipe. By setting the heat retention mode in advance on the operation panel, the pump is activated to circulate water in the circulation pipe when hot water supply is stopped, and the flow rate and temperature of the circulating water detected by the flow rate sensor and temperature sensor are controlled. The amount of heat of the burner is controlled based on the set temperature set by the temperature setting means of the controller, the circulating water is kept warm at the set temperature, and the temperature is set immediately when the water heater at the end of the hot water supply pipe, for example, a water faucet, is opened. It is designed to be able to discharge hot water.

However, in such hot water heaters, thermal insulation operation is mainly used in the winter season, and thermal insulation operation is used in summer because the temperature of the supplied water itself is high and there is no need to take the trouble to keep it warm. There aren't many things.

On the other hand, if a pump is left unused for a long period of time, it may rust and stop working.

Therefore, if the hot water heater is not used for several months, such as during the summer, the pump may become rusty and the pump may not operate even if the hot water heater is then tried to perform a warm operation.

(Problem to be Solved by the Invention) The problem to be solved by the invention is that in a water heater with a heat retention function, the pump is operated periodically regardless of whether or not the heat retention operation is performed.

(Means for solving the problem) The technical means taken by the present invention to solve the above problem is to connect the midway part of the hot water supply pipe and the water supply pipe with a return pipe, so that the water supply pipe and the heat exchange A circular circulation pipe is formed by the water heater, the hot water supply pipe, and the return pipe, and a flow rate sensor and a temperature sensor are installed at appropriate locations in the circulation pipe within the water heater body, and a hot water supply pipe is installed in the return pipe in the circulation pipe. In a gas instantaneous water heater each equipped with a pump that circulates water in the circulation pipe when the water heater is stopped, means for generating a drive signal to the pump drive circuit in conjunction with turning on the operation switch of the water heater; a timer means that starts when the input is made;
and means for generating a stop signal to the pump drive circuit in response to a time-up signal from the timer means.

(Function) According to the above-mentioned technical means of the present invention, the motor is driven for a certain period of time every time the operation switch of the water heater is turned on, that is, almost every day, regardless of whether the hot water heater is in the heat-retaining operation or not.

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

In Fig. 2, A is the main body of the water heater, and 8 is the operation panel. The supplied water is heated by a heat exchanger 4 and flows into the hot water supply pipe 1.

The hot water supply pipe 1 has a water supply device 1 such as a faucet at the terminal.
7 is provided, and the return pipe 3 is branched from a midway part of the pipe, preferably near the water heater 12,
This return pipe 3 is connected to the water supply pipe 2.

Therefore, water supply pipe 2, heat exchanger 4, hot water supply pipe 1
The return pipe 3 constitutes an annular circulation pipe a.

The water supply pipe 2 in the circulation pipe a is provided with a flow rate sensor 5 and a water inflow sensor 6, the hot water supply pipe 1 is provided with an outlet hot water temperature sensor 18, and the return pipe 3 is provided with a pump 7.

In addition, the gas pipe 15 of the water heater main body A has the pipe 15
A solenoid valve 19 that opens and closes the gas, and a proportional valve 20 that proportionally controls the amount of gas are provided.

On the other hand, the operation panel 8 has various operation parts necessary for operating the water heater, such as an operation switch 10, a heat retention operation switch 21, and a temperature setting section 9, and is provided separately from the water heater main body A. It is electrically connected to a control section 22 housed inside the machine base of the machine body A.

The control unit 22 is composed of a microcomputer, and the CPU is equipped with a pump drive signal generation means 12, a timer means 13, and a pump stop signal generation means 14, and the operation switch 10 of the operation panel 8.
When the pump is turned on, the pump drive signal generating means 12 generates a drive signal to the pump drive circuit 11 to drive the pump 7 and start the timer means 13.

The timer means 13 operates for a preset predetermined time, for example, 30 seconds, and generates a time-up signal to the pump stop signal generation means 14 upon time-up.

The pump stop signal generating means 14 receives the time-up signal and generates a pump stop signal to the pump drive circuit 11 to stop the pump 7.

That is, when the operation switch 10 is turned on, the pump 7 always operates for a predetermined period of time, in this case 30 seconds.

In addition, in order to prevent the pump 7 from running dry when there is no water in the circulation pipe a for some reason, a water flow switch 23 is provided in the pipe a and a dry run judgment means is installed in the CPU of the control section 22. 24 is provided, and the pipe a is connected based on the signal from the water flow switch 23.
The presence or absence of water is determined, and if there is no water, the pump drive circuit 1 is sent via the pump stop signal generating means 14.
1 generates a pump stop signal and immediately starts pump 7.
It is designed to stop the operation of the

After the pump operation for a predetermined period of time is completed when the operation switch 10 is turned on,
Transition to normal operation.

The normal operation of the water heater is that when the water heater 17 is opened, the flow rate sensor 5 detects the flow of water and opens the electromagnetic valve 19 of the gas pipe 15, and the burner 16 is ignited by the ignition of the igniter 25. The required heat load F ₁ of the feed water is calculated based on the amount of water detected by the water flow, the incoming water temperature detected by the incoming water temperature sensor 6, and the set temperature set in the temperature setting section 9 of the operation panel 8. Calculate the required heat load _F2 of the feedback using the hot water temperature to be used and the set temperature above, and calculate the required heat load of these feedbacks.
The required heat load F is calculated from _F1 and the required heat load of the feedback _F2 , and the gas piping 15 is adjusted according to the value of F.
The gas amount is varied by adjusting the opening degree of the proportional valve 20,
In some cases, the solenoid valve 19 may be opened and closed intermittently,
Burner 16 depending on the ratio of the valve opening time and valve closing time.
This system controls the amount of heat in the hot water and supplies hot water at a set temperature.Furthermore, by turning on the heat retention operation switch 21, that is, by selecting the heat retention operation, the pump 7 is activated to circulate the water when hot water supply is stopped. Water is circulated through pipe a, and the gas amount is varied by adjusting the opening degree of the proportional valve 19 based on the required heat load F ₁ of the feed forward or the required heat load F ₂ of the feedback, or by using a solenoid valve. 20 is opened and closed to perform intermittent combustion, and the amount of heat heated by the burner 16 is controlled by the ratio of the combustion time and extinguishing time,
The system keeps the circulating water at a set temperature in preparation for the next hot water supply.

All such operations are controlled by the control unit 22, but
Since this is not the gist of the present invention, the explanation will be omitted.

Although the drawing shows a heat exchanger equipped with one burner, it is also possible to install two burners for the heat exchanger and use only one burner for combustion depending on the required heat load. , the amount of heat is controlled by selecting whether to burn two burners simultaneously, or by selecting a burner with a small capacity and burning it intermittently during warm operation, and at other times, one or both burners are switched to gas. It is also possible to control the amount of heat by proportional control.

(Effects) As described above, the present invention includes a means for generating a drive signal to the pump drive circuit in conjunction with turning on the operation switch of the water heater, a timer means that starts when the operation switch is turned on, and a time-up signal of the timer means for pumping the water heater. Since the drive circuit is equipped with means for generating a stop signal, the pump operates for a certain period of time each time the water heater is turned on, ie, almost every day.

Therefore, even if the heat-retaining operation is not performed for a long period of several months, the pump will not rust, and there will be no inconvenience such as the pump not operating the next time the heat-retaining operation is attempted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a pump protection device for a gas instantaneous water heater showing an embodiment of the present invention, FIG. 2 is a schematic diagram of the gas instantaneous water heater, and FIG. 3 is a flowchart. a...Circulation pipe, 1...Hot water supply pipe, 2...Water supply pipe, 3...Return pipe, 4...Heat exchanger, 5...
Flow rate sensor, 6...Temperature sensor, 7...Pump, 8...Operation panel, 9...Temperature setting section, 10...
Operation switch, 11... Pump drive circuit, 12...
... Pump drive signal generation means, 13 ... Timer means, 14 ... Pump stop signal generation means, 21 ...
Heat retention operation switch.

Claims (1)

[Scope of utility model registration request] The midway part of the hot water supply pipe and the water supply pipe are connected through a return pipe, and the water supply pipe, heat exchanger, hot water supply pipe, and return pipe form a circular circulation pipe, and the above-mentioned circulation within the water heater body is formed. In a gas instantaneous water heater, a flow rate sensor and a temperature sensor are installed at appropriate places in the pipe, and a pump is installed in the return pipe in the circulation pipe to circulate the water in the circulation pipe when hot water supply is stopped. means for generating a drive signal to the pump drive circuit in conjunction with turning on the operation switch of the machine; timer means that starts when the operation switch is turned on; and means for generating a stop signal to the pump drive circuit in response to a time-up signal from the timer means. A pump protection device for gas instant water heaters.