JPS62266353A - Instantaneous hot water supplying device - Google Patents

Abstract

PURPOSE:To prevent a delay in outputting hot water and a post-boiling phenomenon by a method wherein a return pipe is connected between a connector for a terminal end hot water supplying faucet and a water supplying pipe and a post-boiling preventing means is provided for operating a circulation pump under an operation of a control device after the terminal hot water supplying faucet is actuated. CONSTITUTION:A connector 9 has a flow rate control valve 12 and may act a uniform pressure to a plurality of terminal hot water supplying faucet 11. As a circulation pump 16 is driven, hot water is circulated through a return pipe 14, so that a proper control of the driving of a burner 2 enables a decreasing in temperature of hot water in the hot water supplying pipe 8 and the connector 9 and an irregular distribution of temperature to be prevented. A subtraction means 31 in a control device 26 may calculate a difference DELTAT between sensed temperatures T1 and T2 of temperature sensors 21 and 22, and its output is compared by a comparison means 32 with a set value T0 set by a temperature difference setting unit 27. Further, the state sensing means 33 detects that a flow sensor 18 may detect no flow of water. Thus, both an output from the comparison means 32 and an output from the state sensing means 33 are inputted to AND means 34 and a post-boiling preventive means 36 is driven. That is, only when a relation of DELTAT>T0 is met and no flow of water into a heat exchanger 6 is found, the circulation pump 16 is operated.

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.

When you open a terminal hot water faucet 2 connected to, for example, a faucet or faucet, water moves through the water supply pipe to the heat exchanger.

After being heated by the heat of combustion in the burner, the hot water flows through the hot water supply pipe and flows out from the terminal hot water tap.

[Problem that the invention seeks to solve]

By the way, with conventional instantaneous hot water heaters, the water temperature in the hot water supply pipe has dropped after a relatively long time has passed since the last use, so when you open the terminal hot water tap.

Initially, cold water will flow 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 fully opened, and the uneconomical problem of discarding a large amount of water.

Another disadvantage of instantaneous hot water heaters is that when hot water is temporarily interrupted and then restarted, if the interruption is short, the temperature of the hot water will rise rapidly, and the hot water will be quite high when the hot water is restarted.

There is also a so-called after-boiling phenomenon.

[Means for solving problems]

The instant hot water supply device according to the present invention includes a burner that burns fuel, a heat exchanger that is heated by the combustion heat of the burner,
It includes 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, and controls the hot water temperature by changing the combustion amount (including zero) in the burner. In the instant hot water supply device, a connector connected to the tip of the hot water supply pipe, a terminal hot water tap connected to the connector, a return pipe connected between the connector and the water supply pipe, It includes a circulation pump and a reverse valve connected to the return pipe, and a control device that controls driving of the burner and the circulation pump, and the control device operates the circulation pump after opening and closing the terminal hot water tap. It is characterized by having an after-boiling prevention means.

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

Referring to FIG. 1 in its entirety, 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. The burner 2 burns fuel supplied by a fuel pump 3 in a 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 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 extended to the outside of the main body 1, and a connector 9 is connected to the tip thereof. A plurality of (for example, five) terminal hot water taps 11 such as faucets are connected to the connector 9 . 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.

It applies equal pressure to a plurality of terminal hot water taps 11, and is called a pressure equalization header. 13 indicates drain pulp.

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 pump 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 34/min. Also check valve 1
It goes without saying that 7 prevents water from flowing back through the return pipe 14.

Further, near the inlet of the heat exchanger 6, a 70-sensor 18 is provided to detect the presence or absence of water flow in the water supply pipe 7. Also, near the outlet of the heat exchanger 6, there is a first temperature detector 21 such as a thermistor for detecting the temperature of hot water in the hot water supply pipe 8.
is provided. In addition, the connector 9K is connected to a second temperature detector 2 consisting of a thermistor or the like that detects the temperature of the water inside the connector 9K.
2 is provided.

The instantaneous water heater of this embodiment further includes a control device 26. This control device 26 includes the above-mentioned 70-sensor 1
8. First temperature detector 21. and second temperature detector 22
Depending on the output from the fuel pump 3 and circulation pump 16, etc.
This controls the driving of the

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 9 ignition signal. After the water supplied through the water supply pipe 7 is heated by the heat exchanger 6, it passes through the hot water supply pipe 8 and the connector 9 and flows out from the terminal hot water tap 11 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 main body 1 through the surroundings of the heat exchanger 6 and the exhaust pipe 5.

By the way, when the circulation pump 16 is driven, the return pipe 14
Since hot water is circulated throughout, by appropriately controlling the drive of the burner 2C, it is possible to prevent a drop in the temperature of the hot water inside the hot water pipe 8 and the contactor 9, and to prevent uneven straining. Therefore, after a relatively long time has passed since the last use, the terminal hot water tap 11
Even if you open it, you can get the desired hot water in a short time. As a result, there is an inconvenience that the hot water is delayed.

FIG. 2 shows a control device 26 that can prevent the uneconomical effects of discarding too much water. The control device 26 includes subtraction means 31 for calculating the difference ΔTi between the detected temperatures T, , T2 at the first and second temperature detectors 21, 22. Subtraction means 3
The output from 1 is the set value T set by the temperature difference setting device 27. and is compared in the comparison means 32. Only when ΔT>To, a logic “1” is output from the comparison means 32.

Further, the state of the flow sensor 18 is detected by a state detection means 33. The state detection means 33 outputs logic 01'' only when the flow sensor 18 detects that there is no flow of water.

The output of the comparison means 32 and the output of the state detection means 33 are as follows.

The signal is input to the logical product means 34, and the after-boiling prevention means 36 is driven based on the output thereof. That is, only when ΔT>To and no water flows into the heat exchanger 6, the afterboiling prevention means 36 is driven and the circulation pump 16 is operated.

In this case, the operation time of the circulation pump 16 is a constant time set by the timer 37.

Now, if the terminal hot water tap 1] is opened to supply hot water and then the terminal hot water tap 11 is closed, the above-mentioned after-boiling phenomenon is about to occur. That is, as water no longer flows into the heat exchanger 6, the temperature of the hot water in the heat exchanger 6 rises rapidly. At this time,
The flow sensor 18 detects that there is no flow of water, and the difference ΔT between the detected temperatures TI+T2 at the first and second temperature detectors 21 and 22 becomes equal. Therefore, both the comparing means 32 and the state detecting means 33 output logic "1". Then, the after-boiling prevention means 36 is driven and the circulation pump 16 is operated, as can be seen from the @statement.

When the circulation pump 16 is operated in this manner, the heat exchanger 6.
Hot water pipe 8. Connector 9. Since the hot water flows through the circulation path passing through the return pipe 14, it is no longer possible for only a portion of the hot water to be excessively heated. That is, the after-boiling phenomenon is substantially prevented, and the risk of hot water being tapped out at a high temperature at the beginning of restarting hot water taping is avoided.

After this, when the circulation pump 16 stops, the flow sensor 18 detects that there is no water flow.

The state detection means 33 outputs a logic "1".

At this time, the output from the comparing means 32 becomes logic "0" by averaging the hot water temperature, so the circulation pump 16 is not restarted.

By the way, in the above description, the operation time of the circulation pump 16 is determined by the timer 3.
Although the period of time has been described as a certain period of time set in 7, it may be determined based on other requirements. for example.

△TNT. The circulation pump 16 may be stopped when this occurs.

Furthermore, in the above description, the operation of the circulation pump 16 is controlled based on the difference ΔT between the temperatures T, , T2 detected by the first and second temperature detectors 21, 22;
1, the detected temperature T is to some extent T4 (T4 is, for example, 95
°C), the second temperature sensor 21
The circulation pump 16 may be started regardless.

In addition, hot water pipe 8. Connector 9. As can be seen from the other embodiments shown in FIG. 6, one of the return pipes 14 is provided with a latent heat storage material 41 facing the main body 1 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 a minute pilot 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,
Since a drop in the temperature of hot water in the hot water supply pipe is reliably prevented, hot water can always be obtained within a relatively short time, thereby eliminating the inconvenience of delayed hot water supply and the uneconomical effects of discarding a large amount of water. Moreover, there is also the advantage that the so-called after-first-break phenomenon is prevented.

[Brief explanation of drawings]

FIG. 1 is a political 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 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 diagram 1, 2nd factor

Claims (1)

[Claims] 1) A burner that burns fuel, a heat exchanger heated by combustion heat in 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. Changes in the amount of combustion in the burner (including zero)
In an instantaneous hot water supply device that controls hot water temperature by a return pipe, a circulation pump and a check valve connected to the return pipe, and a control device that controls the drive of the burner and the circulation pump, and the control device controls the operation of the hot water after opening and closing the terminal hot water tap. An instant hot water supply device characterized by having a post-boiling prevention means for operating a circulation pump.