JPH0233003Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for an instantaneous water heater.

Conventionally, in this type of instantaneous water heater, if the amount of water flowing through the water heater becomes too small, the water flowing through the water boils, and this boiling water is discharged from the hot water tap, which is extremely dangerous. For this reason, in conventional systems, a minimum amount of water that does not cause boiling (hereinafter this water amount is referred to as the minimum operating water amount) is determined, and a water flow switch that detects water flow is designed to operate at or above the minimum operating water amount. , combustion was not allowed to occur below the above-mentioned amount of water.

However, in the conventional example, the minimum operating water flow is set at a certain amount (in most cases, the limit amount of water that does not boil when the gas burner's capacity is at its minimum), so if the capacity is high, the house will boil, which is dangerous. Also, it was not easy to use.

The present invention aims to solve the above-mentioned problems of the conventional method and provide an instant water heater that is easy to use and does not boil at any capacity.The present invention is based on an embodiment shown below. The configuration will be specifically explained.

1 is a heat exchanger, 2 is a gas burner that heats the heat exchanger 1, and the gas burner 2 includes a plurality of burner elements 2.
a, 2b, 2c, 2d, and 2e, and the gas passages 3 leading to these burner elements 2a to 2e are branched from the downstream side of the former solenoid valve 4, and each branched gas passage 3a, 3b, 3c, 3d, and 3e has a Solenoid valve 5a,
5b, 5c, 5d, and 5e are interposed. 6 is a water amount detector installed in the water supply channel 7 leading to the heat exchanger 1;
is the feed water temperature detector. 9 is a water control valve controlled by a controller described later. 10 is a hot water tap. Reference numeral 11 denotes a remote controller installed in a place where hot water is used, such as the kitchen.The remote controller 11 is equipped with a capacity setting device 12 for switching the number of combustion gas burners 2, a temperature setting device 13 for adjusting the hot water temperature, and an operation switch 14. be. 15 is a controller.

Next, the general structure of the above-mentioned controller will be explained based on FIG.
The water supply temperature (Tw) is detected from the water supply temperature detector 8, the water flow rate (Q) is detected from the water flow rate detector 6, and the remote controller 11
The setting capacity signal and the setting temperature (To) are input from The capacity setting device 12 controls the number of combustion elements of the burner element from five to one by changing the setting position, and at the same time sends a signal (hereinafter referred to as setting capacity) of the combustion amount corresponding to the number of combustion elements to the arithmetic control section 16. (W) is output.

In the above configuration, when the operation switch 14 is turned on and the hot water tap 10 is opened to start water flow, the arithmetic control unit 16 displays the set capacity (W), set temperature (To),
The feed water temperature (Tw) and water flow rate (Q) are input, and when the water flow rate (Q) reaches the minimum operating water flow rate in the arithmetic control unit 16, the combustion control circuit 22 is activated to start combustion, and the control water flow rate (Tw) is input. Qo) Qo=25×W/
(To-Tw) and is controlled by a servo circuit (not shown) so that the water flow rate (Q) of the water control valve 9 matches the control water volume (Qo).

Therefore, in the above embodiment, even if the set capacity (W) and the water supply temperature (Tw) are varied, the water control valve 9 is controlled so that the water flow rate is such that the outlet temperature becomes the set temperature (To), so that a stable temperature is always maintained. Hot water can be dispensed, and the amount of hot water dispensed can also be changed.

Then, the hot water tapping calculation control unit 16 calculates the minimum operating water amount Q1 from the above-mentioned setting capacity (W) and water supply temperature (Tw) as Q1 = 25 × W / (80 - Tw),
The water flow rate (Q) and the minimum operating water volume are determined by the determination means 19.
Compared with Q1, the water flow rate (Q) is the lowest operating water flow Q1
If the condition is below, the reset circuit 21 is activated to return the arithmetic control section 16 to its initial state, cut off the combustion signal to the combustion control circuit 22, and thus stop combustion. As can be seen from the above equation, the minimum operating water amount Q1 varies depending on the setting capacity (W) and the water supply temperature (Tw), so the minimum operating water amount Q1 varies depending on the setting capacity and external conditions. is set, boiling can be completely prevented no matter what condition the hot water is in.

In the above example, combustion is controlled using the minimum operating water flow rate Q1, but the combustion field starting flow rate (QON)
Let QON=1.1×Q1 and combustion stop flow rate (QOFF)
By setting QOFF=Q1 and providing hysteresis between QON and QOFF, stable hot water can be dispensed.

As explained above, in short, the present invention includes a heat exchanger, a gas burner consisting of a plurality of burner elements for heating the heat exchanger, a water quantity detector installed in a water channel having the heat exchanger, and a feed water temperature detector. and a capacity setting device for switching the number of combustion elements of the gas burner element.
The minimum operating water amount is calculated based on the combustion capacity set with the capacity setting device and the feed water temperature from the feed water temperature detector, and this minimum operating water amount is compared with the detected water amount from the water amount detector to determine the temperature of the gas burner. Since it is equipped with a controller that controls combustion, it is possible to completely prevent boiling and provide a safe instantaneous water heater of this type.

[Brief explanation of the drawing]

The drawing shows one embodiment of the present invention.
The figure is an overall configuration diagram of an instantaneous water heater, and Figure 2 is an electric circuit diagram. DESCRIPTION OF SYMBOLS 1... Heat exchanger, 2... Gas burner, 6... Water amount detector, 8... Water supply temperature detector, 15... Controller.

Claims (1)

[Scope of utility model registration request] A heat exchanger, a gas burner consisting of a plurality of burner elements that heat the heat exchanger, a water quantity detector installed in a waterway having the heat exchanger, a feed water temperature detector, and the ability to switch the number of combustion elements of the gas burner element. The minimum operating water amount is calculated based on the setting device, the combustion capacity set with the capacity setting device, and the water supply temperature from the water supply temperature detector, and this minimum operating water amount is compared with the water amount detected from the water amount detector. A control device for an instantaneous water heater, comprising a controller for controlling combustion of the gas burner.