JP2734075B2 - Power supply for combustion equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device of a combustion apparatus for improving a hysteresis characteristic of a proportional control valve for adjusting a combustion amount.

2. Description of the Related Art As shown in FIG. 3, a proportional control valve 2 for controlling the amount of combustion generally has a hysteresis characteristic in opening and closing operation (when a valve is operated in an opening direction and in a closing direction) as shown in FIG. When the same control voltage is applied, the degree of opening and closing varies.) Therefore, the AC voltage is superimposed on the control voltage, and a small vibration is applied to the proportional control valve 2 to reduce the hysteresis characteristic. To improve. The superimposed AC power supply is provided with a winding S on a power supply transformer 11 of the control circuit 6. In the figure, 5 is an operation switch, and 10 is a drive transistor which is turned on / off by the control circuit 6.

However, in the conventional configuration, the power supply to the control circuit 6 and the like is based on a power supply circuit using a transformer 11, and a switching power supply that has been frequently used in recent years is used as a main power supply. When used, there is a problem that the power supply transformer is eliminated and the AC power supply superimposed on the proportional control valve 2 is trapped.

Even if a separate transformer is provided to solve the above problem, the proportional control valve 2 will always vibrate minutely by merely superimposing an alternating current, and the internal diaphragm of the proportional control valve 2 will be deteriorated and the mechanical parts will be deteriorated. There is a problem in the durability of
Since a power supply opening / closing means is required, optimization of the opening / closing method and insertion position has been an important solution.

The present invention is to solve such a problem, and is to provide an AC power supply superimposed on a control voltage of a proportional control valve even when a control circuit switching power supply is used.

Means for Solving the Problems To achieve the above object, a power supply device of the present invention comprises: a switching power supply for supplying power to a control circuit of a combustion device;
A proportional control valve that controls the combustion amount of the combustion equipment, an AC superimposing transformer that superimposes an AC voltage on the control voltage of the proportional control valve in order to improve the hysteresis characteristics of the proportional control valve, and in conjunction with the operation of the combustion equipment A power switch for opening a power supply on a primary side of the AC superposition transformer.

According to the present invention, a main power supply such as a control circuit of a combustion device is provided by a switching power supply, an AC superimposing transformer provided separately supplies an AC voltage to a proportional control valve, and the AC superimposing transformer operates the combustion device. , The AC application to the proportional control valve is performed in conjunction with the movement operation.

Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention. A switching power supply 1 supplies power to a control circuit 6 and a proportional control valve 2. The direct current path of the proportional control valve 2 is a diode 7
After passing through the secondary winding S of the AC superimposing transformer 3, it is supplied to the proportional control valve 2 and returns to the ground via the driving transistor 10. The magnitude of the current is controlled by the drive transistor 10, and the proportional control valve 2 changes the degree of opening and closing in proportion to the magnitude of the current.

The AC current path of the proportional control valve 2 is an AC superimposed transformer 3
From the secondary winding S through the bypass capacitor 8 and the current limiting resistor 9 to the proportional control valve 2 and returns to the secondary winding S of the AC superimposed transformer 3 again. The proportional control valve 2 is slightly vibrated by the superimposed alternating current, and the hysteresis characteristic is improved. The power switch 4 is a relay contact driven by the relay coil 11, and when the operation switch 5 is operated and the operation sequence of the control circuit 6 proceeds, the relay coil 11 is driven and closed. Accordingly, the AC superimposing transformer 3 is connected to the power line only during the operation, no AC current flows during the standby, and the proportional control valve 2 is in a stationary state.

Figure 2 is a block diagram showing another embodiment of the present invention, is provided with a flame rod voltage winding S _f for flame detection in the secondary winding S of the AC superimposed transformer 3. (Frame rod ...
An electrode that is installed in a flame, and when a voltage is applied between the burner and the electrode, ions in the flame cause a current to flow. Effects of the Invention As is clear from the above embodiments, the power supply device of the present invention has the following effects.

A switching power supply can be used as the main power supply of the combustion equipment, and the characteristics of the switching power supply, such as small size, large capacity, and stable output voltage, can be utilized to reduce the size of the combustion equipment and improve various performances.

Further, the AC superimposed transformer may have a small power supply capacity for giving a minute vibration to the proportional control valve, and may be incorporated in a printed wiring board together with a control circuit.

Further, since the power supply of the AC superimposing transformer is interlocked with the operation switch, a minute vibration is applied to the proportional control valve only during the operation, and the life and durability of the proportional control valve can be increased. In addition, since the AC superposition transformer opens and closes the primary winding, there is no loss such as iron loss of the transformer in a standby state, and power consumption of a device in a standby state can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a power supply device for a combustion apparatus according to the present invention, FIG. 2 is a block diagram showing another embodiment, and FIG. 3 is a block diagram showing a conventional example. 1 ... Switching power supply, 2 ... Proportional control valve, 3 ... AC superimposed transformer, 4 ... Power switch.

Claims (1)

(57) [Claims] 1. A switching power supply for supplying power to a control circuit of a combustion device, a proportional control valve for controlling a combustion amount of the combustion device, and a control of the proportional control valve for improving hysteresis characteristics of the proportional control valve. A power supply device for a combustion device, comprising: an AC superposition transformer for superimposing an AC voltage on a voltage; and a power switch for opening and closing a power supply on a primary side of the AC superposition transformer in conjunction with an operation of the combustion device.