JPH05272772A - Control method of mixing ratio upon resupplying hot-water in tap-controlled hot-water supplier - Google Patents

Abstract

PURPOSE:To eliminate affection on a supplying hot-water temperature by a method wherein the temperature of the outlet side of a heat exchanger and a cold water temperature at the bypass side are detected at all times while the mixing ratio of a control valve is operated to control the control valve so as to obtain a set temperature. CONSTITUTION:The mixing ratio of hot-water, heated in a heat exchanger 1, and cold water coming through a bypass 4 is controlled by a control valve 5 so that a supplying hot-water temperature becomes a preset temperature. In this control, the hot-water temperature of the outlet side of the heat exchanger 1 and the cold water temperature (feed water temperature) of the side of the bypass 4 are detected by temperature sensors 6, 7 respectively while the detected values are inputted into a controller 9. The controller 9 operates a mixing ratio for obtaining the set temperature based on the temperatures detected by the temperature sensors 6, 7 and controls the control valve 5 immediately to obtain supplying hot-water temperature the same as the set temperature. According to this method, the change of the supplying hot-water temperature can be eliminated even when the performance of the hotwater supplier is changed due to aging, the change of circumstance and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instantaneous hot water heater having a structure in which hot water from the heat exchanger side and cold water from the bypass side are controlled by a control valve to control the hot water temperature.

[0002]

2. Description of the Related Art In a conventional instantaneous hot water heater (hereinafter referred to as "water heater"), the outlet temperature is set at a set temperature by proportionally controlling the mixing ratio of hot water from the heat exchanger side and chilled water from the bypass side with a control valve. 2, the opening of the control valve is determined by the absolute amount depending on the time after the hot water is stopped, as shown in FIG. 2, regardless of the set temperature and the temperature of the hot water on the side of the heat exchanger. Mixing is being performed with that setting until the state is reached.

[0003]

Therefore, there are the following problems.

A. Even if there is a secular change in the heat exchanger or the gas burner or a change in the feed water temperature, these factors are not taken into consideration, so the hot water temperature at the time of re-hot water changes depending on the period of use, season, etc.

B. The amount of residual heat in the heat exchanger 1 fluctuates depending on the time from the stop of use to the restart of operation, but since this fluctuation value is not considered at all,
In particular, there is a large fluctuation in the tapping temperature until the steady state is entered.

C. The temperature gradient in each part of the residual hot water in the water heater is low on the control valve side and highest in the heat exchanger 1. Therefore, the problem of residual heat quantity at the time of re-melting can not be solved by ignoring this temperature gradient, but in the past, since it was decided to be a single rate in time, the temperature control at the time of re-melting is not always satisfactory. .

An object of the present invention is to eliminate the above problems a, b and c.

[0008]

The structure of the instant type hot water heater according to the present invention is as follows.

In an instantaneous water heater having a structure in which the hot water from the heat exchanger side and the cold water from the bypass side are controlled by a control valve to control the hot water discharge temperature, in the heat exchanger discharge side and the water supply side, respectively. A method for controlling a mixing ratio at the time of re-leaving hot water in an instantaneous water heater, in which a temperature sensor is attached, and a mixing ratio of the control valve is calculated based on a signal from the temperature sensor and a set temperature to drive the control valve.

[0010]

The mixing ratio of the hot water heated by the heat exchanger and the cold water that has passed through the bypass is controlled by the control valve so that the hot water outlet temperature becomes a preset temperature. In this control, the temperature of the hot water on the outlet side of the heat exchanger and the temperature of the cold water on the bypass side (feed water temperature) are respectively detected by the temperature sensor, and this value is input to the controller. The controller calculates the mixing ratio that reaches the set temperature based on the temperatures detected by both temperature sensors, and immediately controls the control valve to control the outlet heated water temperature to the set temperature.

[0011]

EXAMPLE FIG. 1 shows an example of the present invention.

1 is a heat exchanger, 2 is a water supply side, 3 is a tap water side,
4 is a bypass, 5 is a control valve, 6 is a temperature sensor attached to the outlet side of the heat exchanger 1, 7 is a feed water temperature sensor attached to the feed water side, 8 is a gas burner, and 9 is a controller,
Perform the following control.

When the operation switch is turned on, the gas burner 8 is ignited, and at the same time, the temperature sensors 6 and 7 detect the outlet temperature of the heat exchanger 1 side and the cold water temperature of the water supply side 2 to set the set temperature. Based on the calculation of the mixing ratio, a control signal is output to the control valve 5. The control valve 5 controls the mixing ratio of the cold water on the heat exchanger 1 side and the bypass 4 side based on this control signal.

An arithmetic expression for determining the mixing ratio of hot water and cold water in the controller 9 is as follows.

[0015]

[Equation 1]

However, T _S : Set temperature T _W : Temperature of heat exchanger 1 side t ₀ : Cold water temperature of feed water 2 side

The effects of the present invention are as follows.

A. The control valve is controlled by constantly detecting the outlet temperature of the heat exchanger and the chilled water temperature of the bypass side and calculating the mixture ratio of the control valve to reach the set temperature. Even if the change occurs, the effect on the tap water temperature disappears.

B. In intermittent use, even if the residual heat quantity (post-boiling temperature) varies depending on the time until reuse, the tapping temperature is not affected.

C. The post-boiling temperature has a temperature difference (gradient) depending on the position, but it is not affected by this temperature difference at the start-up at the time of tapping again.

[Brief description of drawings]

FIG. 1 is an explanatory view of a water heater according to the present invention.

FIG. 2 is an explanatory view of the opening degree of a conventional control valve.

[Explanation of symbols]

 1 Heat Exchanger 2 Water Supply Side 3 Hot Water Supply Side 4 Bypass 5 Control Valve 6 Temperature Sensor 7 Water Supply Temperature Sensor 8 Gas Burner 9 Controller

Claims (1)

[Claims] 1. An instantaneous water heater having a structure in which hot water from the heat exchanger side and cold water from the bypass side are controlled by a control valve to control the hot water discharge temperature. A method for controlling the mixing ratio at the time of re-releasing hot water in a momentary water heater, in which temperature sensors are attached to the respective units, and the mixing ratio of the control valve is calculated based on the signal from the temperature sensor and the set temperature to drive the control valve.