JPH0615256Y2 - Water heater - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) [0001] The present invention relates to a water heater, and more particularly to a water heater equipped with a flow rate control valve that automatically adjusts the flow rate of water flow so as not to exceed the capacity range. It is a thing.

(Prior Art) In a conventional water heater of this type, for example, the actual open Sho 60-1317.
As disclosed in Japanese Patent Publication No. 67, the flow rate control valve is rotated by a motor or the like to change the opening area of the valve body peripheral surface facing the outlet, so that the hot water supply lan is not over-passed even when fully opened. The flow rate of water is reduced to allow the hot water at the set temperature to be discharged.

(Problems to be solved by the invention) In this type, when the hot water is discharged at the maximum temperature in the winter when the water inlet temperature is low, the flow control valve has an extremely narrowed flow rate, but at this time, the water supply pressure fluctuates. If the pressure drops suddenly, the flow rate of water flow may decrease to less than the minimum operating flow rate of the water heater, which may extinguish the burner. Further, when the flow rate control valve is driven from a wide open state to an extremely narrowed state, the motor may overrun and the water flow rate may be excessively narrowed down to the minimum operating flow rate or less.

In the former case, the former cannot operate until the water pressure rises again, and in the latter case, the flow control valve is over-throttled, so the water flow rate does not exceed the minimum operating flow rate and the operation cannot be performed. It had the problem of falling.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a water heater capable of automatically re-releasing hot water when stopped due to the influence of water pressure fluctuations or the flow control valve being excessively throttled, resulting in a stop below the minimum operating flow rate. I am trying.

(Means for Solving the Problems) In order to achieve the above object, the water heater of the present invention has the following configuration. That is, a flow rate sensor for detecting the flow rate of water flow, a water temperature sensor for detecting the temperature of water flow, a flow rate control valve for controlling the flow rate of water flow, and a drive device for driving the flow rate control valve are provided. When the detected water flow rate is equal to or higher than the minimum operating flow rate, control the flow rate control valve so that it does not exceed the maximum water flow rate calculated based on the set temperature, water temperature, and the heating capacity of the water heater. A controller is provided for driving the flow rate control valve to the fully open position at the end of a predetermined post-purge time after the water flow rate detected by the sensor becomes equal to or lower than the minimum operating flow rate.

(Embodiment) FIG. 1 is a schematic configuration diagram of a water heater showing an embodiment of the present invention. (1) is a heat exchanger, (2) is a burner, and (3) is an air supply fan. Water passage (4) on the inlet side of the heat exchanger (1)
A flow rate sensor (5), a water temperature sensor (6), and a flow rate control valve (7) are provided in the. (8) is a servomotor (driving device) for driving the flow rate control valve (7). (9) is a controller and (10) is a hot water temperature setting device. The flow rate control valve (7) may be provided in the hot water dispenser (11).

Fig. 2 is a control flow chart. When it is detected that the water flow rate (Q) detected by the flow rate sensor (5) is equal to or higher than the minimum operating flow rate (MOQ) when the hot water supply run is opened (FI), the burner Ignite (2), set temperature (TS) of hot water temperature setting device (10)
And the water temperature (TC) detected by the water temperature sensor (6)
And the maximum water flow rate (QS) is calculated based on the maximum capacity number (M) of the water heater, and the water flow rate (Q) detected by the flow rate sensor (5) is the maximum water flow rate described above. The servo motor (8) is controlled so that it coincides with (QS), and the opening of the flow rate control valve (7) is adjusted (F2). That is, the maximum water flow rate (QS) is Is calculated, and the servomotor (8) is controlled by comparing with the water flow rate (Q).

Then, when it is detected (F3) that the flow rate (Q) of the hot water supply is closed and the flow rate (Q) is less than the minimum operating flow rate (MOQ), the burner (2) is extinguished and the air supply fan (3) is operated for a predetermined period of time. Continue post-purging for a period of time (F4). When post-purge is completed, the servo motor (8) is driven to set the flow rate control valve (7) to the fully open position (F5).

However, when the hot water supply pressure suddenly drops when the hot water supply curran is not closed but the opening of the flow rate control valve (7) is narrowed to control the flow rate to be slightly larger than the minimum operating water amount (MOQ), Alternatively, when the servo motor (8) is driven in a direction to reduce the opening of the flow rate control valve (7) due to a change in the set temperature (TS), the servo motor (8) overruns and the flow rate control valve (7) ) If the opening is too narrow, the water flow rate (Q) becomes less than the minimum operating flow rate (MOQ), the burner (2) extinguishes, and in these cases the water heater becomes inoperable. . Therefore, in the water heater of the present invention, since the flow rate control valve (7) is driven to the fully open position after that, the water flow rate (Q) increases and the operation can be automatically restored, and after the post-purging is completed. By driving the flow control valve (7), the residual gas immediately after the burner (2) is extinguished can be discharged to ensure the re-ignition.

(Effects of the Invention) The water heater of the present invention has the following excellent effects. In other words, it does not fall into the inoperable state when stopped due to the influence of water pressure fluctuations and the throttle of the flow control valve due to overrun of the drive device, it can automatically return to the operable state and can be safely re-activated. Can be done.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a water heater showing an embodiment of the present invention, and FIG. 2 is a control flowchart of the embodiment. (7) …… Flow rate control valve (8) …… Servo motor (drive device)

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Claims (1)

[Scope of utility model registration request] 1. A flow rate sensor comprising: a flow rate sensor for detecting a flow rate of water flow; a water temperature sensor for detecting a water flow rate; a flow rate control valve for controlling the flow rate of water flow; and a drive device for driving the flow rate control valve. When the water flow rate detected by the sensor is greater than or equal to the minimum operating flow rate, the flow rate control valve is controlled so that it does not exceed the maximum water flow rate calculated based on the set temperature, incoming water temperature, and heating capacity of the water heater. In addition, the water heater is provided with a controller that drives the flow rate control valve to the fully open position at the end of a predetermined post-purge time after the water flow rate detected by the flow rate sensor becomes equal to or less than the minimum operating flow rate.