JPS62261857A - Instantaneous hot-water supplier - Google Patents

Abstract

PURPOSE:To eliminate the inconvenience of the delay of supplying hot-water as well as the uneconomical throwing-away of much amount of water by providing a controller which effects the combustion of a burner and drives a circulating pump when one of both temperatures, detected by a first and second temperature detectors, is lower than a predetermined value. CONSTITUTION:A first temperature detector 21, which detects hot-water temperature in a hot-water supplying pipe 8, is provided near the outlet port of a heat exchanger 6 while a second temperature detector 22, which detects hot-water temperature in a connector 9, is provided in the connector 9. Both detected temperatures T1, T2 of the first and second temperature detectors 21, 22 are compared with a set temperature T0 in first and second comparing means 31, 32, respectively. An OR means 33 outputs a temperature keeping signal when there is an input from at least one of the first and second comparing means 31, 32. The temperature keeping signal is inputted into a circulating pump driving control means 34 to drive a circulating pump 16. On the other hand, the temperature keeping signal is transmitted to an AND means 35 and a fuel pump driving control means 36 controls the driving of a fuel pump 3 to effect the combustion of a burner 2. When a temperature keeping mode is selected, the circulating pump 6 and the burner 2 are driven intermittently and the temperature reduction of hot-water in the hot-water supplying pipe 8 and the connector 9 may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an instantaneous water heater 9 used in general households, such as a stop-start water heater directly connected to a water supply.

[Conventional technology]

Conventionally, this type of instantaneous hot water heater has a terminal hot water tap 2 connected to a hot water pipe terminal, such as a water faucet or faucet, when opened.

Water moves through the water supply pipe to the heat exchanger, is heated by combustion heat in the burner, and then flows out through the hot water supply pipe and from the terminal hot water tap.

[Problem that the invention seeks to solve]

By the way, in conventional instantaneous hot water heaters, the water temperature in the hot water supply pipe has dropped after a relatively long period of time since the last use, so when the terminal hot water tap is opened, cold water initially flows out. That is, it takes time for the hot water heated by the heat exchanger to flow through the hot water supply pipe to the terminal hot water tap. This causes problems such as the inconvenience that hot water does not come out immediately even when the terminal hot water tap is opened, and the uneconomical problem of discarding a large amount of water.

[Means for solving problems]

A heat exchanger, a water supply pipe connected to the inlet side of the heat exchanger, and a hot water supply pipe connected to the outlet side of the heat exchanger,
In the device that controls the hot water temperature by changing the amount of combustion (including zero) in the burner, the nf is connected to the tip of the hot water pipe.
A C connector, a terminal hot water tap connected to the connector, a C return pipe connected between the connector and the water supply pipe, and a circulation pump and check valve connected to the return pipe. and a first temperature detector that detects the temperature of the hot water coming out of the heat exchanger, and a second temperature detector that detects the temperature of the hot water in the connector.

and a control device that causes the burner to perform combustion and drives the circulation pump when at least one of the temperatures detected by the first and second temperature detectors is below the predetermined value. It is characterized by

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, an instantaneous water heater according to an embodiment of the present invention includes a main body 1 of the water heater.

A burner 2 is installed inside the main body 1. Burner 2
The fuel supplied by the fuel pump 3 is combusted in the combustion chamber 4. An exhaust pipe 5 is provided above the combustion chamber 4.

A heat exchanger 6 is arranged in the combustion chamber 4. A water supply pipe 7 on the inlet side, a water supply pipe 7 on the outlet side, and a hot water supply pipe 8 on the outlet side are connected to the heat exchanger 6. The water supply pipe 7 is directly connected to a household water pipe (not shown). On the other hand, the hot water supply pipe 8 is led out to the outside of the main body 1, and a connector 9 is connected to the tip thereof. The connector 9 has a plurality of (for example, three) terminal hot water faucets 1 such as faucets.
1 is connected. It is desirable that the distance from the connector 9 to the terminal hot water tap 11 be short. The connector 9 has a built-in flow control valve 12 and applies equal pressure to a plurality of terminal hot water taps 11, and is called a pressure equalization header.

13 indicates a drain valve.

A return pipe 14 is further connected at one end to the connector 9. The other end of the return pipe 14 is connected to the water supply pipe 7. A circulation pump 16 and a check valve 17 are connected to such a return pipe 14 . The circulation 2 pipe 16 moves the water in the return pipe 14 in the direction from the connector 9 to the water supply pipe 7, and has a small capacity with a flow rate of 2 to 317 minutes. ! check valve 17
Needless to say, this prevents water from flowing backward through the return pipe 14.

Furthermore, near the inlet of the heat exchanger 6, a sensor 70-sensor 18 is provided to detect the presence or absence of water flow n in the water supply pipe 7. Near the outlet of the heat exchanger 6, there is a first temperature detector 21 made of a thermistor or the like that detects the temperature of hot water in the hot water pipe 8.
is provided.

The connector 9 is also provided with a second temperature detector 22 made of a thermistor or the like that detects the temperature of the water inside the connector 9.

The instantaneous water heater of this embodiment further includes a control device 26. This control device 26 includes the flow sensor 1 described above.
8. First temperature detector 21. and second temperature detector 22
Depending on the output from the fuel pump 3 and circulation pump 16, etc.
The drive is fully controlled.

The instantaneous hot water supply device of this embodiment has a hot water supply mode and a warming mode, and is designed to be able to switch between these modes using a manual switch. The hot water supply mode is a mode indicating a normal usage state in which the terminal hot water tap 11 is opened and closed relatively frequently. The heat retention mode is a mode for preventing the temperature of the hot water inside the hot water pipe 8 and the connector 9 from decreasing.

First, a brief description will be given of the case where the hot water tap mode is selected. When hot water supply is stopped, combustion in burner 2 is also stopped. When the terminal hot water tap 11 is opened, fuel supplied from the fuel pump 3 is combusted in the burner 2 based on the first ignition signal. After the water supplied through the water supply pipe 7 is heated by the heat exchanger 6, the water supply pipe 8 and the connector 9't-way are connected to the terminal hot water tap 11.
It flows out as hot water. Further, the combustion gas generated in the burner 2 is transferred to the combustion chamber 4. It is discharged to the outside of the two main bodies 1 through the surroundings of the heat exchanger 6 and the exhaust pipe 5.

By the way, when the circulation pump 16 is driven, hot water circulates through the return pipe 14, so by appropriately controlling the drive of the burner 2, it is possible to prevent the temperature drop and temperature unevenness of the hot water inside the hot water supply pipe 8 and the connector). can. Therefore, even if the terminal hot water tap 11 is opened after a relatively long time has elapsed since the previous use.

You can get the desired hot water in a short time.

As a result, it becomes possible to eliminate the inconvenience of delayed hot water supply and the uneconomical problem of discarding a large amount of water.

FIG. 2 shows the controller 26 in the keep warm mode.

Referring to FIG. 2 in addition to FIG. 1, both the detected temperatures T1tT2 of the first and second temperature detectors 21.22 are compared with the set temperature To in the first and second comparison means 31.32, respectively. compare. The first comparison means 31 outputs to the OR means 33 only when r Tl <To. The second comparing means 32 is.

It is output to the logical sum means 33 only when 'r2<To. The logical sum means 33 includes the first and second comparison means 31
．． When there is an input from at least one of 32, a heat retention signal is output. The heat retention signal is sent to the circulation pump drive control means 3.
4, and the circulation pump 16 is driven by and n.

This heat retention signal is also sent to the logical product means 35.

When the circulation pump 16 is driven, the flow sensor 18 detects the flow n of hot water flowing into the heat exchanger 6. The flow n detection signal from the flow sensor 18 is also sent to the AND means 35. From the logical product means 35.

The heat retention signal and the flow n detection signal are output to the fuel pump drive control means 36 only when both are input.

According to this output, the fuel pump drive control means 36 controls the drive of the fuel pump 3 to cause the burner 2 to perform combustion. When the above-mentioned heat retention signal disappears, combustion stops.

Therefore, when the heat retention mode is selected, the circulation pump 6 and the burner 2 are activated from time to time, thereby reliably preventing the temperature of the hot water inside the hot water pipe 8 and connector 9 from decreasing.

In addition, hot water pipe 8. Connector 9. As can be seen from other embodiments shown in FIG. 3, two of the return pipes 14 are provided with latent heat storage materials 41 facing each other and covered with a heat insulating material 42. It is desirable to provide a heat insulation structure. Further, the same method can be applied to an instantaneous water heater of the type that shifts to minute combustion when hot water supply is temporarily stopped.

〔Effect of the invention〕

As explained above, according to the instantaneous water heater of the present invention,
It is possible to switch between hot water dispensing mode and heat preservation mode, and since the temperature preservation mode reliably prevents the temperature of hot water in the hot water supply pipe from dropping, hot water can be obtained in a relatively short time when switching to hot water dispensing mode. This eliminates the inconvenience of slow hot water supply and the uneconomical waste of large amounts of water.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of the present invention, FIG. 2 is a functional block diagram of a control device, and FIG. 3 is a schematic configuration diagram of only the main parts of another embodiment. 1... Water heater body, 2... Burner, 3... Fuel pump, 6... Heat exchanger, 7... Water supply pipe, 8...
Hot water pipe, 9... Connector, 11... Terminal hot water tap, 14
... Return pipe, 16... Circulation pump, 18... Flow sensor, 21... First temperature detector, 22... Second temperature detector, 26... Control device.

Claims (2)

[Claims] (1) A burner that burns fuel, a heat exchanger that is heated by the combustion heat of the burner, a water supply pipe connected to the inlet side of the heat exchanger, and a water supply pipe connected to the outlet side of the heat exchanger. In an instantaneous water heater that controls the hot water temperature by changing the amount of combustion (including zero) in the burner, the instantaneous water heater includes a hot water supply pipe connected to the hot water supply pipe, and a connector connected to the tip of the hot water supply pipe; A connected terminal hot water tap, a return pipe connected between the connector and the water supply pipe, a circulation pump and a check valve connected to the return pipe, and a temperature of hot water output from the heat exchanger. 1st to detect
a temperature detector, a second temperature detector that detects the temperature of the hot water in the connector, and at least one of the temperatures detected by the first and second temperature detectors is below the predetermined value. An instantaneous hot water supply apparatus characterized in that the instantaneous hot water supply apparatus is further equipped with a control device for causing combustion in the burner and driving the circulation pump. (2) The control device includes a first comparing means that compares a first temperature detected by the first temperature detector with a set temperature, and outputs an output when the first detected temperature is lower than the set temperature. a second comparison means that compares a second temperature detected by the second temperature detector with the set temperature and outputs an output when the second detected temperature is lower than the set temperature; and a circulation pump drive control means for driving the circulation pump according to the output of at least one of the second comparison means and the second comparison means.