JPH0590252U - Water heater - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the temperature of the hot water from rising due to a sudden decrease in the amount of water during tapping. [Structure] The water heater main body 1 has a water amount sensor 6 on the water supply side.
It is composed of a feed water temperature thermistor 7, a heat exchanger 2 having a tap water temperature thermistor 8 on the tap water side, a fuel controller 9, an AC blower 5, and a combustion section 3 having a burner 4. The AC blower 5 that supplies the air necessary for combustion is applied with a DC voltage as appropriate, so that the brake can be instantaneously applied. [Effect] Compared to the conventional case where the applied voltage is simply set to 0 V to reduce the rotation speed, the rotation speed can be drastically decreased, and the overshoot of the tap water temperature when the flow rate is reduced can be suppressed to a lower level. I was able to.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a technique for rapidly lowering the rotation speed of an AC blower used for a water heater.

[0002]

[Prior Art]

 Currently, an AC blower is widely used to supply the air required for burner combustion in a water heater. This is to supply air into the combustion chamber in an amount commensurate with the amount of fuel consumed by controlling the rotation speed of the blower using phase control or the like.

[0003]

[Problems to be solved by the device]

 However, in such a conventional example, as a method of rapidly lowering the rotation speed of the AC fan motor, the structure is such that at most, the voltage applied to the fan can be set to 0 V. In order to prevent overshoot of the hot water temperature due to the sudden reduction of the flow rate, even when the calorific value of the burner must be sharply reduced, to prevent lift, flashback and incomplete combustion, There is a problem in that it is not possible to increase the decrease speed of the burner heat generation rate more than the decrease speed of the fan motor rotation speed when the fan applied voltage is set to 0 V, and thus it is impossible to avoid overshooting to some extent. there were.

Explaining in a specific example, when the user suddenly squeezes the hot water tap 12, or when the amount of water sharply decreases due to fluctuations in water pressure, an excessive overshoot of the hot water temperature is prevented, so that the required amount of heat is generated. As described above, it is preferable to lower the calorific value as quickly as possible by the fuel controller 9, but generally, the maximum lowering speed of the calorific value is the lowering speed of the rotational speed of the AC blower 5 even if the applied voltage is 0V. Even so, it is not possible to obtain a sufficient descending speed due to the inertial force of the fan blades.

For this reason, in the conventional method, even when it is desired to rapidly reduce the heat generation amount, in the case where the balance between the fuel amount and the air amount is controlled, the rotation speed of the AC blower 5 is reduced when 0 V is applied. The calorific value cannot be reduced faster than the speed that can balance the speed. As a result, there was a problem that the time during which radical heating was applied to the amount of water was lengthened, and tapping characteristics such as overshoot deteriorated.

[0006]

[Means for Solving the Problems]

 The present invention was made in view of such conventional problems, and as a method of sharply reducing the rotation speed of an AC fan motor, by applying a DC voltage to the fan motor as appropriate, It aims to solve problems.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. First, the structure will be described. The water heater body 1 is composed of a water circuit and a combustion unit 3. The combustion section 3 includes a fuel controller 9, an AC blower 5, and a burner 4. In the water circuit, a water amount sensor 6 and a water supply temperature thermistor 7 are provided on the water supply side of the heat exchanger 2, and a hot water temperature thermistor 8 is provided on the hot water discharge side of the heat exchanger 2. Reference numeral 10 is a water heater control means, 11 is a hot water temperature setting switch, and 12 is a tap for a shower, a faucet, or the like.

[0008]

[Action]

 Next, the operation will be described. When the tap 12 is opened, a water flow occurs in the water circuit, and if the water amount sensor 6 detects a certain amount or more of running water, the control means 10 causes the commutation blower 5 to supply the air required for combustion. At the same time, the fuel regulator 9 and the ignition device (not shown) are activated to ignite the burner 4.

The control means 10 controls the fuel controller 9 and the blower 5 by feedback control so that the output of the hot water temperature thermistor 8 becomes the temperature set by the hot water temperature setting switch 11. The control at this time is based on the feedback control described above so as to obtain the necessary heat generation amount calculated from the respective outputs of the water supply temperature thermistor 7, the water amount sensor 6, and the set temperature set by the hot water temperature setting switch 8. It may be one to which feed forward control for controlling 9 or the like is added.

In the present invention, a DC voltage is applied to the AC blower 5 as needed, the rotation speed is positively braked, and the maximum decrease speed of the rotation speed is increased, so that the heat generation amount can be reduced more quickly. As a result, the tapping property can be improved. Here, it is possible to sharply reduce only the heat generation amount while ignoring the balance between the fuel and air amounts, but it goes without saying that excessive air combustion causes abnormal combustion.

FIG. 2 shows a case in which the applied voltage is set to 0 in order to reduce the rotation speed of the AC blower 5 when the water flow rate is rapidly reduced from the Q ₁ flow rate to the Q ₂ flow rate, and the DC voltage is applied by the present invention. This is a schematic representation of the behavior of the calorific value of the burner 4 and the rotational speed of the AC blower 5 when braking is appropriately performed. By increasing the descent speed of the AC blower 5, as shown by the shaded area in the figure, the excess calorific value until the calorific value of the burner 4 after the flow rate becomes Q ₂ becomes the necessary calorific value at the flow rate Q _2. You can see that it will be reduced.

[0012]

[Effect of the device]

 As described above, according to the present invention, it is possible to instantaneously brake the fan motor by applying a DC voltage to the AC fan motor as appropriate. Compared to the case where the rotation speed is reduced by setting 0V to 0V, the rotation speed can be drastically reduced. Therefore, the calorific value of the burner, which is normally controlled while maintaining a balance with the rotation speed of the fan motor, can also be drastically lowered, and overshoot of the hot water temperature when the flow rate is reduced, etc. The effect is that it can be kept lower and the usability for the user can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[FIG. 2] In order to reduce the rotational speed of the AC blower when the water flow rate is sharply reduced, (a) the case where the conventional applied voltage is set to 0, and (b) the braking by the DC voltage application of the present invention is appropriately performed. It is a figure which shows the behavior of a calorific value of a burner and an AC blower rotation speed at the time of performing.

[Explanation of symbols]

 1 Water Heater Main Body 2 Heat Exchanger 3 Combustion Section 4 Burner 5 AC Blower 6 Water Volume Sensor 7 Water Supply Temperature Thermistor 8 Hot Water Temperature Thermistor 9 Fuel Controller 10 Control Means 11 Hot Water Setting Switch 12 Hot Water Tap

Claims (1)

[Scope of utility model registration request] 1. A heat exchanger, a water amount sensor, a feed water temperature sensor, a hot water temperature sensor, a combustion unit, a fuel controller for adjusting the combustion amount, and an AC blower for supplying combustion air to the combustion unit. In the water heater using the water heater, when a sudden decrease in the amount of water is detected by the water amount sensor, a direct current is appropriately applied to the AC blower.