JPS6330033Y2 - - Google Patents

Description

[Detailed description of the invention] This invention provides instant hot water heating by circulating hot water by interposing a pump in a hot water flow path formed by a radiator and a heat exchanger heated by a combustion burner. The purpose of boiler heaters is to prevent a decrease in thermal efficiency during low loads.

Conventionally, this type of heater has generally been equipped with an exhaust fan for the purpose of improving exhaust capacity and thermal efficiency. However, during full-throttle combustion, the amount of combustion air can be maintained constant according to the amount of fuel, and a certain degree of thermal efficiency can be ensured, but when combustion is performed under low load, for example, the efficiency suddenly drops. This is mainly due to the fact that the exhaust fan continues to rotate for a while due to inertia even after combustion has stopped during ON-OFF cycle repetition, and therefore heat is radiated backward from the heat exchanger section.

Therefore, the present invention provides a system that can avoid the above-mentioned problems by applying a brake to the exhaust fan to stop its rotation in a short period of time when combustion is stopped.

The present invention will be explained below based on one embodiment.

Reference numeral 1 denotes an exterior casing of an instant water heater, and inside the casing 1 there are a hot water inlet pipe 2, a heat exchange section 3,
A hot water outlet pipe 5 to which a temperature sensing element 4 is attached, a heat exchanger drum body 6 that supports the heat exchange section 3, a burner section 7 installed inside the drum body 6, and control of fuel supply to the burner section 7. a solenoid valve 8 that performs this, an exhaust hood 9 located above the heat exchange section 3,
an exhaust pipe/exhaust fan 10 for discharging exhaust gas collected by the exhaust fan 10; an electric motor 1 for driving the exhaust fan 10;
The rotation detecting body 12 attached to the main shaft 11 of 0' is housed therein.

The rotation detection body 12 is capable of rotating a predetermined portion of the main shaft 11 and outputting an electric signal corresponding to the rotation.

During normal operation, hot water circulated by a pump (not shown) or the like flows in from the hot water inlet pipe 2, flows out from the hot water outlet pipe 5, and radiates heat by a radiator (not shown) or the like, repeating the cycle. Naturally, when there is little external heat radiation, the temperature of the hot water rises, which is sensed by the temperature sensing element 4, and the solenoid valve 8 is closed to stop combustion in the burner section 7.

13 is a power connection port, and 14 is a main switch, which is closed during operation. 15 is a contact part of a relay 16 as a first switching means, which is connected to the contact 17 side when the winding part RL _A is not energized, and is connected to the contact 18 side when the winding part RL _A is energized. Switch.
19 is a fan stop circuit, and exhaust fan 10
The drive motor 10' is connected to the drive motor 10'. 20 is a transformer, 21 is a rectifier, and 22 is a rotation detection circuit including the rotation detector 12, which receives a signal from the rotation detector 12 when the main shaft 11 reaches a constant rotation and sends an operating current to the relay 23. It is. 24 is a control circuit as a second switching means, which compares the temperature detected by the temperature sensing element 4 with the set temperature, and when the detected temperature is less than the set temperature, the power supply circuit of the winding part RL _A is inserted. The switch 25 is opened, and the switch 26 between the winding section RL _B and the rotation detection circuit 22 is closed, and when the detected temperature is higher than the set temperature, the switch 25 is closed.
control to close the switch 26 and open the switch 26. 28
is the contact point of the relay 23, and the winding part RL _B of the relay 23
is closed in the excited state, energizing the electromagnetic valve 8, instructing the supply of fuel, and operating the discharge ignition circuit 29.

With this configuration, the main switch 14
If the water temperature is below the set temperature after pouring the water, the contact part 15
The electric motor 10' is energized through the contact 17, and the exhaust fan 10 rotates. Detecting this rotation, the rotation detecting circuit 22 energizes the winding part RL _B of the relay 23 via the switch 26, and energizes the solenoid valve 8 via the contact 28 of the relay 23 to start fuel supply and discharge. The ignition circuit 29 is activated and combustion begins. Next, when the water temperature becomes high, the control circuit 24
A second switching means consisting of switches 25 and 26 performs control as follows. First of all, switch 26
is opened and the switch 25 is closed, the power to the winding part RL _B is turned off, the contact part 28 is opened, the power to the solenoid valve 8 is turned off, combustion is stopped, and the power to the winding part RL _A is When energization starts, the contact part 15 becomes contact 1.
8 side, the power to the electric motor 10' is turned off, and the fan stop circuit 19 is activated to stop the exhaust fan 10. Therefore, when combustion is stopped during repeated ON-OFF cycles, there is no reverse heat dissipation from the heat exchange section 3 as in the conventional case, and thermal efficiency at low loads can be improved.

As explained above, according to the present invention, the exhaust fan device is switched from the driving state to the stopped state in conjunction with the stoppage of fuel supply to the burner, and the exhaust fan is immediately stopped. Immediately afterward, the exhaust fan device inertia rotates and heat is removed from the circulating hot water by the low-temperature exhaust flow that occurs in the conventional heat exchanger, which can be avoided. This can improve thermal efficiency under load.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an instant water heater, and FIG. 2 is a configuration diagram of an embodiment of the present invention. 3... Heat exchange section, 4... Temperature sensing element, 7... Burner section, 8... Solenoid valve, 10... Exhaust fan, 16
... Relay [first switching means], 19 ... Fan stop circuit, 22 ... Rotation detection circuit, 24 ... Control device.

Claims (1)

[Scope of utility model registration request] A pump is interposed in a hot water flow path formed by a radiator and a heat exchanger heated by a combustion burner to circulate hot water, and exhaust gas from the combustion burner is forcibly discharged. an exhaust fan device, a drive circuit that energizes the exhaust fan device, a stop circuit that applies braking to the exhaust fan device, a first switching means that selects between the drive circuit and the stop circuit, and rotation of the exhaust fan device. A rotation detection circuit that detects the speed and a rotation detection circuit that compares the target temperature with the temperature detected by the temperature sensing element attached to the hot water flow path outlet of the heat exchanger to determine the switching state of the first switching means and the rotation detection circuit of the solenoid valve. and a second switching means for controlling opening/closing based on the output of the exhaust fan device, and when the detected temperature is below the target temperature, the second switching means switches the first switching means to the drive circuit side. and the solenoid valve is brought into a fuel supply state according to the output of the rotation detection circuit, and when the detected temperature reaches the target temperature, the second switching means brings the solenoid valve into a fuel supply stop state and the first solenoid valve is brought into a fuel supply state. An instant water heater configured to switch the switching means to the stop circuit side to stop the exhaust fan device.