JPS6144111Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a water heater, and more particularly to a water heater that adjusts the temperature of hot water by controlling the amount of fuel supplied, such as city gas.

Typical prior art techniques include a preset temperature;
The opening degree of a control valve installed in the middle of a fuel, for example, city gas supply pipe, was adjusted so that the hot water supply temperature would match the set temperature by comparing the hot water temperature detected by a thermistor or the like. However, if you set the hot water temperature to a high temperature during times when the water temperature is low, such as in the winter,
Furthermore, when the amount of hot water supplied is increased, the hot water temperature may not reach the set value even if the control valve is fully opened and the amount of fuel supplied is maximized. In this case, it is necessary to manually operate the hot water supply valve to reduce the amount of hot water supplied, but if the water heater is throttled too much, the water heater may automatically turn off the fire, or the opening of the control valve may become small, causing the hot water to flow. The boiler may not reach its maximum capacity.

Another prior art is shown, for example, in Japanese Patent Application Laid-open No. 51-33, in which a heat exchanger is heated by a burner to which an amount of fuel gas is supplied, and hot water from the heat exchanger is used for hot water supply. If the hot water supply valve is opened too much, it will be maintained at the set temperature by adjusting the water volume, and conversely, if the hot water supply valve is narrowed too much, the set temperature will be maintained by adjusting the amount of fuel gas. It is configured to maintain

The problem with this prior art is that if the hot water heater is throttled too much, hot water can be maintained at the set temperature by adjusting the amount of fuel gas. There is a problem in that it is not possible to make full use of the capabilities of the device, and no efforts have been made to address this issue.

The purpose of the present invention is to provide a water heater with improved efficiency by maximizing the capacity of the water heater.

The present invention includes a burner 4, a heat exchanger 7 heated by the burner 4, and a hot water supply cooker 9 that supplies hot water from the heat exchanger 7.
, a temperature detector 14 that detects the temperature of hot water at the outlet of the heat exchanger 7, and a control valve 11 that controls the fuel flow rate to the burner 4.
and a throttle valve 13 that controls the flow rate of water at the inlet of the heat exchanger 7; and a throttle valve 13 that is arranged upstream of the water from the throttle valve 13 so that the flow rate of water to the heat exchanger 7 is equal to or higher than a predetermined value. a flow switch 12 for detecting the temperature of the hot water from the heat exchanger 7; a temperature setting device 15 for setting the temperature of the hot water from the heat exchanger 7; The control valve 11 includes a comparator 18 that derives a comparison output L representing a temperature difference Δt between the set temperature t1 of the control valve 11 and the hot water supply temperature t2 detected by the temperature detector 14. The control valve 11 is fully open when the comparison output L is equal to or higher than a predetermined first value L1, and fully closed when the comparison output L is equal to or lower than a predetermined second value L2.
The opening degree is controlled so that the temperature difference Δt becomes zero between the value L2, and when the temperature difference t is zero, the opening is close to fully open. After a predetermined time elapses after the detection of the flow switch 12, a delay circuit 26 that derives a delayed output responds to the output of the flow switch 12, the comparison output L, and the delayed output, and there is a delayed output, and When the comparison output L is greater than or equal to the first value L1, the throttle valve 13
When the flow switch 12 detects that the water flow rate is less than a predetermined value, the throttle valve 13 is fully opened, and the comparative output L is set to the first value. This water heater is characterized in that it includes a throttle control circuit 24 that stops the throttle operation of the throttle valve 13 when the opening degree of the control valve 11 becomes slightly smaller than the fully open state by less than L1.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an embodiment of the present invention.
In this gas instantaneous water heater 1, a fuel such as city gas is passed through a pipe 3 as shown by an arrow 2 to a burner 4.
is supplied to On the other hand, water is supplied to a heat exchanger 7 via a pipe 6 as indicated by an arrow 5. This heat exchanger 7 is placed directly above the burner 4, and hot water heated by combustion in the burner 4 is supplied via a pipe line 8 and a hot water supply line 9.

A control valve 11 is provided in the middle of the pipe line 3, and a throttle valve 13 is provided in the middle of the pipe line 6. The control valve 11 and the throttle valve 13 are controlled to open and close by the control means 10. This control means 10
A temperature detector 14 such as a thermistor is provided in the middle of the pipe line 6, and a flow switch 12 is provided on the upstream side of the throttle valve 13 of the pipe line 6.

The flow switch 12 is turned on when water flows through the pipe 6 at a preset flow rate or higher, and sends the signal to the temperature setting device 1 via the line 16.
Enter 5. The temperature setting device 15 is equipped with a setting knob (not shown), and can freely set the hot water temperature. The output of temperature setter 15 is input via line 17 to one input of comparator 18 . The output of the temperature detector 14 is input to the other input terminal of the comparator 18 via a line 19.
In the comparator 18, each output value of the temperature setting device 15 and the temperature detector 14, that is, the set temperature t1 and the hot water supply temperature t2, are compared, and as shown in FIG. 2, the difference Δt between the set temperature t1 and the hot water supply temperature t2 is calculated. (=t1−
t2), a comparison output L is output. This comparison output L is input to an amplifier 21 via a line 20, amplified by the amplifier 21, and then input to the control valve 11 via a line 22.

The opening degree of the control valve 11 is controlled according to the comparison output L as shown in FIG. In other words, the comparison output L
When the comparison output L is equal to or greater than L1, the opening becomes fully open, and when the comparison output L is equal to or less than L2, the opening becomes fully closed. In addition, in FIG. 3, the operating straight line 27 is moved in the left-right direction of FIG. 3 according to the set temperature, and when the set temperature is high, the temperature difference Δt is changed as shown in FIG.
When is zero, the opening degree of the control valve 11 is close to fully open.

The signal from flow switch 12 is on line 16
The signal is input to the aperture control circuit 24 via a line 23 branched from the line 23 and a delay circuit 26. Further, the comparison output L of the comparator 18 is inputted to the aperture control circuit 24 via a line 25 branched from the line 20. This throttle control circuit 24 reduces the opening degree of the throttle valve 13 when the output of the delay circuit 26 is at a high level and the comparison output L is equal to or higher than L1, and also controls the output of the flow switch 12 via lines 16 and 16a. Therefore, when the flow switch 12 is turned off, it has a function of fully opening the throttle valve 13 and allowing water to flow at a minimum flow rate. The output of the delay circuit 26 becomes high level after a certain period of time has elapsed since the flow switch 12 was turned ON, that is, the operation was started. Here, the certain period of time is selected to be, for example, 20 to 60 seconds during which the temperature of the hot water supply becomes stable.

When operating the gas instantaneous water heater 1, a pilot burner (not shown) is ignited to set the water supply temperature, and then water is supplied to the pipe line 6. This conduit 6 ₁
When the flow rate of water exceeds the set value, the flow switch 12 is turned ON, and the opening degree of the control valve 11 changes to the difference Δ between the set temperature t1 and the hot water supply temperature t2.
The combustion amount of the burner 4 is controlled proportionally according to t.

When such a gas instantaneous water heater 1 is operated, when the water temperature is high such as in summer, the comparison output of the comparator 18 is within the range of more than L2 and less than L1, and the hot water temperature is lower than that of the control valve 11. The set temperature is maintained within the control range. Next, assume that the set temperature is increased when the water temperature is low in winter. In this case, even if the control valve 11 is fully opened and the combustion amount of the burner 4 reaches its maximum value, the hot water supply temperature t2 may not reach the set temperature t1. In such a case, when 20 to 60 seconds have passed since the flow switch 12 was turned ON, the delay circuit 26 is connected to the aperture control circuit 24.
and a high level signal from line 25.
The comparison output of L1 or higher is input. As a result, the opening degree of the throttle valve 13 is narrowed down and the amount of water supplied is reduced. As the water supply amount decreases, the hot water supply temperature t2 approaches the set temperature t1. In this way, by reducing the water supply amount, the hot water supply temperature t2 becomes the set temperature t1.
controlled accordingly.

In the throttle control circuit 24, when the input signal from the line 25 becomes less than L1, the opening degree of the throttle valve 13 is kept constant. That is, when the opening degree of the control valve 11 becomes slightly smaller than the fully open state, the throttling operation of the throttle valve 13 is stopped and the water supply amount is kept constant. Furthermore, the control valve 11 is controlled near its fully open position, and therefore the amount of fuel supplied to the burner 4 is controlled near its maximum amount. Therefore, the gas instantaneous water heater 1 can demonstrate its capabilities to the fullest.

Note that when the hot water supply switch 9 is closed and the operation is stopped, that is, when the flow switch 12 is turned off, the throttle valve 13 is fully opened by the function of the throttle control circuit 24. Therefore, at the start of the next operation, the hot water supply valve 9 can be opened to supply water.

The present invention is not limited to water heaters that use gaseous fuel such as city gas as in the above embodiments, but can be implemented in connection with water heaters that use liquid fuel such as kerosene.

As described above, according to the present invention, the following effects are achieved.

(a) The fuel flow rate to the burner 4 is controlled by a control valve 11, and the flow rate of water at the inlet of the heat exchanger 7 is controlled by a throttle valve 13, which controls the opening degree of the throttle valve. The control circuit 24 stops the throttle operation of the throttle valve 13 when the comparative output L becomes less than the first value L1 and the opening degree of the control valve 11 becomes slightly smaller than the fully open state. Therefore, hot water is supplied from the hot water supply cylinder 9 while the opening degree of the control valve 11 is controlled to be slightly smaller than the fully open state. In this way, it is possible to maximize the capacity of the water heater.

(b) Moreover, with such a configuration, the amount of water supplied from the hot water supply cooker 9 can be kept constant regardless of fluctuations in the hot water supply temperature. Therefore, hot water can be used comfortably.

(c) Moreover, the flow switch 12 is the throttle valve 1.
Since the flow switch 12 is disposed on the upstream side of the water, there is no need to unnecessarily improve the heat resistance of the flow switch 12, and the present invention can be easily realized.

(d) Furthermore, the throttle control circuit 24 controls the throttle valve 1 when the flow switch 12 detects that the flow rate of water is less than a predetermined value.
3 is fully opened. Therefore, when the next hot water supply starts, the hot water supply valve 9 can be opened and hot water can be supplied immediately, without causing any hindrance to the use of hot water.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the output characteristics of the comparator 18, and FIG. 3 is a diagram showing the characteristics of the control valve 11. 1...Gas instantaneous water heater, 3, 6...Pipe line, 4...
...Burner, 10...Control means, 11...Control valve,
13... Throttle valve.

Claims (1)

[Claims for Utility Model Registration] A burner 4, a heat exchanger 7 heated by the burner 4, and a water heater 9 that supplies hot water from the heat exchanger 7.
, a temperature detector 14 that detects the temperature of hot water at the outlet of the heat exchanger 7, and a control valve 11 that controls the fuel flow rate to the burner 4.
and a throttle valve 13 that controls the flow rate of water at the inlet of the heat exchanger 7; and a throttle valve 13 that is arranged upstream of the water from the throttle valve 13 so that the flow rate of water to the heat exchanger 7 is equal to or higher than a predetermined value. a flow switch 12 for detecting the temperature of the hot water from the heat exchanger 7; a temperature setting device 15 for setting the temperature of the hot water from the heat exchanger 7; The control valve 11 includes a comparator 18 that derives a comparison output L representing a temperature difference Δt between the set temperature t1 of the control valve 11 and the hot water supply temperature t2 detected by the temperature detector 14. The control valve 11 is fully open when the comparison output L is equal to or higher than a predetermined first value L1, and fully closed when the comparison output L is equal to or lower than a predetermined second value L2.
The opening degree is controlled so that the temperature difference Δt becomes zero between the value L2, and when the temperature difference t is zero, the opening is close to fully open. After a predetermined time elapses after the detection of the flow switch 12, a delay circuit 26 that derives a delayed output responds to the output of the flow switch 12, the comparison output L, and the delayed output, and there is a delayed output, and When the comparison output L is greater than or equal to the first value L1, the throttle valve 13
When the flow switch 12 detects that the flow rate of water is less than a predetermined value, the throttle valve 13 is fully opened, and the comparative output L is set to the first value. A water heater characterized in that it includes a throttle control circuit 24 that stops the throttle operation of the throttle valve 13 when the opening degree of the control valve 11 becomes slightly smaller than the fully open state by less than L1.