JP2615152B2 - Bypass mixing water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention mixes hot water that passes through a heat exchanger and is heated by heat obtained by burning fuel, and water that bypasses the heat exchanger. The present invention relates to a bypass mixing type water heater for supplying hot water.

[Prior Art] When a temperature of a heat exchanger for exchanging heat with water obtained by combustion of fuel and water, that is, a temperature of hot water flowing through the heat exchanger is low, a water heater generates water generated by fuel combustion. (Drain water) adheres to the heat exchanger, and the durability of the heat exchanger deteriorates.

Therefore, a bypass water channel that bypasses the heat exchanger is provided, and the hot water that has passed through the heat exchanger and has passed through the bypass water channel is mixed downstream of the heat exchanger to maintain the temperature of the heat exchanger high. A bypass mixing type water heater that lowers the temperature of hot water obtained from the water heater is known.

[Problems to be Solved by the Invention] However, in the conventional bypass mixing type water heater, when a low tapping temperature is required, the amount of combustion is reduced accordingly, and the temperature of the heat exchanger is lowered. Then
There has been a problem that the temperature of the heat exchanger decreases and water generated by combustion of the fuel adheres to the heat exchanger.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bypass mixing-type water heater in which drain water does not adhere to a heat exchanger even when a low tapping temperature is required.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following technical configurations.

The bypass mixing type water heater includes a combustion unit for burning fuel, a heat exchanger for exchanging heat with water obtained by combustion of fuel in the combustion unit to heat water, and a heat exchanger for heating water. A bypass water passage for bypassing, a throttle valve for adjusting an amount of water flowing through the bypass water passage, a combustion amount in the combustion section,
And a control circuit for controlling the amount of bypass water by the throttle valve.

And the control circuit is a hot water temperature detecting means for detecting a hot water temperature heated by the heat exchanger, a hot water temperature detecting means for passing the heat exchanger and the bypass water passage and detecting a mixed hot water temperature, And a controller for setting a tapping water temperature. By controlling a combustion amount, at least a tapping temperature detected by the tapping temperature detecting means is kept at a tapping temperature at which the drain water does not adhere to the heat exchanger. The control of the amount of combustion and the control of the amount of bypass water are performed so that the detected hot water temperature becomes the hot water temperature set by the controller.

[Operation] In the present invention having the above-described configuration, even when a low tapping temperature is requested by the controller, the hot water temperature detected by the hot water temperature detecting means is supplied to the heat exchanger by the operation of the control circuit. The amount of combustion in the combustion section is controlled in a state where the temperature is maintained at a temperature higher than the temperature at which the particles adhere.

[Effects of the Invention] According to the present invention, as shown in the above operation, even when a low tapping temperature is required, the tapping temperature is controlled in a state where the drain water does not adhere to the heat exchanger. Therefore, it is possible to reliably prevent the drain water from adhering to the heat exchanger.

[Embodiment] Next, a bypass mixing type water heater of the present invention will be described based on an embodiment shown in the drawings.

FIG. 1 shows a schematic diagram of a bypass mixing type gas water heater.

This gas water heater is roughly divided into a combustion section that burns fuel.
10, a gas supply pipe 20, a water pipe 30, and a control circuit 40.

The combustion unit 10 includes a combustion case 12 in which a surface combustion type burner 11 made of ceramic is disposed, and a blower 13 that supplies air for combustion into the combustion case 12. After combustion, the combustion air guided to the exhaust port is discharged from a not-shown exhaust port as combustion gas.

The gas supply pipe 20 supplies fuel gas to a nozzle 21 that is opened on the inner periphery of the centrifugal fan 14 of the blower 13,
A main solenoid valve 22, a main solenoid valve 23, and a proportional valve 24 are sequentially provided from the upstream side. The downstream side of the proportional valve 24 is branched into two, one of which is provided with a switching solenoid valve 25 and the other with an orifice 26. The original solenoid valve 22, the main solenoid valve 23, and the switching solenoid valve 25 open and close the gas supply pipe 20 by energization control.The opening ratio of the proportional valve 24 changes according to the energization amount. The amount of gas supplied is adjusted.

The water pipe 30, one of which is connected to a water supply source and the other of which is connected to a hot water supply port, exchanges heat generated by combustion of gas of the burner 11 with water flowing inside, and passes through the inside. A heat exchanger 31 for heating water to be heated and a bypass water passage 32 for bypassing the heat exchanger 31 are provided.

The water pipe 30 upstream of the branch between the heat exchanger 31 and the bypass water passage 32 has a governor valve that keeps the amount of flowing water constant even when the water pressure flowing into the heat exchanger 31 and the bypass water passage 32 changes. An electric water flow control device 33 is provided in which the function and the function of a water flow control valve for controlling the water flow are combined. The bypass water channel 32 is provided with a throttle valve 34 for adjusting the amount of water passing through the bypass water channel 32.

The throttle ratio of the electric water flow control device 33 is set to be equal to or smaller than the throttle valve 34 so as to regulate the total amount of water passing through the heat exchanger 31 and the bypass water passage 32. In addition, the electric water flow control device 33 and the throttle valve 34 drive a valve body capable of opening and closing a water passage using a geared motor as a means for adjusting the water flow.

The control circuit 40 includes a microcomputer 41, a relay circuit 42, and a drive circuit 43, as shown in FIG. 2, and controls the burner 11 according to the output of a controller 44 and various sensors operated by a user. The sparker 45, the main solenoid valve 22, the main solenoid valve 23, the proportional valve 24, the switching solenoid valve 25, the electric water flow control device 33, and the throttle valve 34 for igniting the electric power are controlled to be energized.

Various sensors of the control circuit 40 detect the opening by interlocking with the frame rod 46 and the thermocouple 47 for detecting the flame of the burner 11 and detecting the air-fuel ratio, the electric water flow control device 33 and the throttle valve 34. Potentiometers 48, 49,
An air volume detection sensor 50 for detecting the rotation speed of the blower 13, an incoming water temperature sensor 51 for detecting the temperature of the water flowing into the heat exchanger 31 and the bypass water passage 32, and a hot water temperature sensor 52 for detecting the temperature of the hot water passing through the heat exchanger 31 ( Hot water temperature detection means of the present invention), a tapping water temperature sensor 53 that passes through the heat exchanger 31 and the bypass water passage 32 and detects the mixed hot water temperature, and a water amount that detects the amount of water flowing into the heat exchanger 31 and the bypass water passage 32 A detection sensor 54 is provided.

Next, combustion control and water amount control by the computer 41 will be briefly described.

In the combustion control, when the user operates the callan connected to the hot water supply port and a water flow is generated in the water pipe 30, the rotating body in the water amount detection sensor 54 rotates to start combustion. The amount of combustion after the start of combustion is determined by the amount of water obtained by various sensors, the incoming water temperature, the temperature of the hot water that has passed through the heat exchanger 31, and the temperature of the mixing hot water (the hot water temperature) so that the hot water temperature set by the controller 44 can be obtained. The blower 13 is energized so as to supply the burner 11 with an air volume corresponding to the determined combustion volume.
Then, the energization of the proportional valve 24 and the switching electromagnetic valve 25 is controlled so that a gas amount corresponding to the rotation speed of the blower 13 and the flame temperature of the burner 11 is obtained. The amount of combustion is maintained such that the temperature of the hot water that has passed through the heat exchanger is equal to or higher than the temperature at which water (drain water) generated by combustion does not adhere to the heat exchanger 31 (for example, 60 ° C. = the predetermined hot water temperature of the present invention). Is set to

The throttle valve 34 is fixed at an appropriate opening calculated from the incoming water temperature, the hot water temperature that has passed through the heat exchanger 31, and the hot water temperature. The fixing of the opening degree of the throttle valve 34 is released when the amount of incoming water decreases or when the temperature of the hot water is lowered, so that the opening degree calculated according to the decrease of the amount of incoming water or the temperature of the hot water is lowered. The energization of the throttle valve 34 is controlled.

Further, the electric water flow control device 33 is controlled so as not to exceed the maximum flow rate required for obtaining the tap water temperature.

Next, control of the throttle valve 34 when lowering the tapping temperature will be described.

If a low tapping temperature is set by the controller 44 while the throttle valve 34 is fixed, the computer 41 reduces the amount of combustion with a drop in the tapping temperature. However, as described above, the amount of combustion is determined so that the temperature of the hot water that has passed through the heat exchanger 31 is maintained at or above a predetermined hot water temperature (for example, 60 ° C.). Therefore, in order to supply the hot water temperature set by the controller 44, the computer 41 releases the fixing of the throttle valve 34 and lowers the hot water temperature by increasing the opening degree of the throttle valve 34.

That is, when the temperature of the hot water that has passed through the heat exchanger 31 can be controlled by the amount of combustion while maintaining the temperature of the hot water at or above the predetermined temperature, the computer 41 fixes the throttle valve 34 and controls the temperature of the hot water only by controlling the amount of combustion. If the temperature of hot water passing through the heat exchanger 31 falls below a predetermined temperature in controlling the combustion amount, the throttle valve
The outlet temperature is controlled by controlling the opening degree of 34.

According to the present embodiment, even if a low tapping temperature is required, by controlling the opening degree of the throttle valve 34, the tapping temperature flowing through the heat exchanger 31 can be maintained high, and the tapping temperature can be lowered. In addition, it is possible to reliably prevent the drain water from adhering to the heat exchanger 31.

In addition, when a low tapping temperature is required, the tapping amount decreases when the amount of water flowing through the heat exchanger 31 is reduced. However, in the present invention, the amount of water flowing through the bypass water passage 32 is increased.
This has an effect that a larger amount of hot water can be obtained as compared with the case where the amount of water flowing through is reduced.

(Modification) Although an example in which gas is used for combustion has been described, the invention may be applied to a water heater using liquid fuel such as kerosene or heavy oil.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a bypass mixing type gas water heater, and FIG. 2 is a schematic block diagram of a control circuit. In the figure, 10: combustion section, 31: heat exchanger 32: bypass water passage, 34: throttle valve 40: control circuit 52: hot water temperature sensor (hot water temperature detecting means of the present invention)

Claims (1)

(57) [Claims] (A) a combustion section for burning fuel; (b) a heat exchanger for exchanging heat with water obtained by burning fuel in the combustion section to heat water; c) a bypass channel for bypassing the heat exchanger; (d) a throttle valve for adjusting the amount of water flowing through the bypass channel; and (e) control for controlling the amount of combustion in the combustion section and the amount of bypass water by the throttle valve. A hot water temperature detecting means for detecting a temperature of the hot water heated by the heat exchanger; and a hot water mixed through the heat exchanger and the bypass water passage, the mixed hot water being supplied. A hot water temperature detecting means for detecting the temperature, and a controller for setting the hot water temperature, wherein at least the hot water temperature detected by the hot water temperature detecting means is controlled by controlling a combustion amount so that the drain water does not adhere to the heat exchanger. A bypass mixing type hot water supply, wherein the control of the amount of combustion and the control of the amount of bypass water are performed so that the hot water temperature detected by the hot water temperature detecting means is maintained at the hot water temperature set by the controller. .