JPS6319720Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gas combustion amount control device for a proportional control type water heater, and is capable of easily setting an optimum combustion amount range when changing the calorific value of the supplied gas (calorie increase).

First, an example of the configuration of a water heater according to the present invention is shown in FIG. 1. In the figure, reference numeral 1 denotes a heat exchanger of an instantaneous water heater A, in which water entering from a water supply pipe 2 is heated by a gas burner 3 and turned into hot water, which is then supplied from a hot water tap 4. The hot water temperature is detected by a temperature sensing element 5 installed at the outlet of the heat exchanger 1, and the signal is amplified by a control circuit 6 built into the water heater A, which drives the gas proportional control valve 7 to control the gas supply pipes 8, gas governor 9
The amount of gas (gas pressure) sent through the gas burner 3 is controlled, and the amount of combustion in the gas burner 3 is controlled to keep the hot water temperature constant. The gas proportional control valve 7 moves the valve body 11 forward and backward by the attraction and repulsion force between the electromagnet 12 and the magnet 13 connected to the valve body 11 facing the valve hole 10, and adjusts the opening degree of the valve hole 10 to control the secondary gas. The pressure is changed, and the amount of gas flows in proportion to the current value flowing through the coil 14 of the electromagnet 12 output from the control circuit 6.

FIG. 2 is a specific electrical circuit diagram of the same, in which 5 is the above-mentioned temperature sensing element, which uses a thermistor whose resistance value changes depending on the temperature, and is connected via a temperature control volume 16 provided on the remote controller 15. It is connected in series to the power supply. Reference numeral 17 designates an operational amplifier, the positive side input terminal of which receives the potential at the midpoint between the temperature control volume 16 and the temperature sensing element 5, and the negative side of the operational amplifier receives the potential set by fixed resistors 18 and 19, respectively. The output acts on the coil 14 of the gas proportional control valve 7 via the constant current amplifier 20 so that a current corresponding to the output value flows. 21 is operational amplifier 1
This is a maximum current setting volume interposed between the output side of the coil 14 and the input side of the constant current amplifier 20, and the maximum current flowing through the coil 14 is regulated by the volume 21. 22 is the power line and constant current amplifier 20
This is a minimum current setting volume connected between the input side of the operational amplifier 17 and the constant current amplifier 20 when the output from the operational amplifier 17 is not output, that is, when the water temperature reaches the temperature set by the temperature control volume 16. The minimum opening degree of the proportional control valve 7 is regulated by setting the input value. Note that 23 is a transistor that drives the proportional control valve 7 with the output from the constant current amplifier 20.

In a water heater having such a configuration, in order to set the optimum combustion range of the burner when changing the gas (when increasing calories), the upper and lower limits of the secondary gas pressure of the proportional control valve 7 are set by the volumes 21 and 22. However, the conventional adjustment method is to change the opening degree of the hot water tap 4 to the maximum or minimum, and to change the temperature control volume 16 to the maximum or minimum temperature. Alternatively, after creating two conditions that require minimum combustion, each volume 21 and 22 was turned each time, and the settings were set while checking the secondary gas pressure with a manometer, etc., so water heater A and remote controller Adjustment cannot be made without making two or more trips back and forth to and from No. 15, which makes adjustment extremely troublesome if these are installed far apart, such as indoors and outdoors.

The present invention was made with the aim of resolving such difficulties, and to explain its configuration, Fig. 3 is an electrical circuit diagram of the present invention. In addition to the conventional circuit shown in Fig. A bypass circuit 26 is connected to short-circuit the temperature sensing element 5 and the bypass circuit 26, and means for opening either or both of the temperature sensing element 5 and the bypass circuit 26 is provided. As a means for this, for example, a changeover switch 24 that is switched only while being pressed is connected in series in front of the temperature sensing element 5, and its normally open contact 25 is provided in a bypass circuit 26.
A removable connector 27 forming a part of 6
has been established. That is, normally, the changeover switch 2
4 is not pressed, the bypass circuit 26 is open, and when the changeover switch 24 is pressed, the temperature sensing element 5 is opened. When the connector 27 is inserted with the changeover switch 24 pressed, The resistance value of the bypass circuit 26 becomes zero or a very small value, and when the connector 27 is removed, the bypass circuit 26 is also opened and the resistance value becomes infinite. Note that this connector 27
Instead, an ordinary open/close switch may be used, and in short, it is sufficient if either or both of the temperature sensing element 5 and the bypass circuit 26 can be opened.

To explain how to set the secondary gas pressure using this circuit configuration, first press the selector switch 24 with the connector 27 inserted, and the bypass circuit 26 will be activated.
Since the resistance value is almost zero and the same state can be created as when the temperature sensing element 5 detects the highest water temperature, the minimum current setting volume 22 is then turned to adjust it to the predetermined lower limit secondary gas pressure. Next, switch 2
Remove the connector 27 while pressing 4 to create the state when the temperature sensing element 5 detects the lowest water temperature, and then turn the maximum current setting volume 21 to adjust it to the predetermined upper limit secondary gas pressure. .

In this way, by creating a pseudo temperature state of the highest and lowest hot water outlet temperatures in the bypass circuit 26 without actually operating the temperature sensing element 5, the hot water tap 4 and the temperature control volume 16 can be controlled in the same manner as in the past. Since the upper and lower secondary pressure limits can be set without changing the water temperature, there is no need to go back and forth between the appliance and the remote control.

In summary, the present invention continuously controls the drive current of the gas proportional control valve in accordance with the temperature signal from the temperature sensing element whose resistance value changes depending on the detected hot water temperature.
In a proportional control gas water heater having a maximum current setting volume and a minimum current setting volume that respectively set the maximum opening degree and minimum opening degree of the gas proportional control valve, a bypass circuit that short-circuits the temperature sensing element is provided. Since the device is equipped with a means to open either or both of the temperature sensing element and the bypass circuit, it has the advantage of making it extremely easy to set the secondary gas pressure when changing gases, and has a great practical effect. It is something.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a proportional control type gas water heater according to the present invention, Fig. 2 is a conventional electric circuit diagram of the same water heater, and Fig. 3 is an electric circuit diagram showing an embodiment of the present invention. be. 5... Temperature sensing element, 7... Gas proportional control valve, 21
...Volume for maximum current setting, 22...Volume for minimum current setting.

Claims (1)

[Scope of utility model registration request] The driving current of the gas proportional control valve is steplessly controlled in accordance with the temperature signal from the temperature sensing element whose resistance value changes depending on the detected hot water temperature, and the maximum opening and minimum opening of the gas proportional control valve are respectively set. In the device having a maximum current setting volume and a minimum current setting volume, a bypass circuit is provided to short-circuit the temperature sensing element, and means is provided for opening either or both of the temperature sensing element and the bypass circuit. A combustion amount control device for a proportional control type gas water heater, characterized by: