CN105828461B - A kind of electric heating equipment shutdown delay cooling control circuit and cooling protection method - Google Patents

Abstract

The invention discloses a shutdown delay cooling control circuit and a cooling protection method for electric heating equipment, wherein the circuit comprises: the electric heating device comprises a power supply, an electric heater, a fan, a delay circuit and a delay control circuit, wherein when the electric heating device is started, the power supply is connected with the electric heater and the fan and supplies power to the electric heater and the fan; when the electric heating equipment is shut down, the power supply is disconnected with the electric heater, the power supply is connected with the delay circuit, the delay circuit is connected with the delay control circuit, and when the time of the delay circuit reaches the preset time, the delay control circuit controls the disconnection of the power supply and the fan. The method comprises the following steps: the electric heating equipment is shut down, the electric heater stops working, and the fan stops working after delaying the preset time. According to the shutdown delay cooling control circuit and the cooling protection method for the electric heating equipment, after shutdown, the fan works in a delay mode for a period of time and then is powered off, so that all power supplies can be automatically cut off after the temperature in the equipment is reduced, and fire disasters caused by overhigh internal heat are avoided.

Description

A kind of electric heating equipment shutdown delay cooling control circuit and cooling protection method

technical field

The invention relates to the technical field of electric heating equipment, in particular to a shutdown delay cooling control circuit and a cooling protection method of the electric heating equipment.

Background technique

At present, there are a large number of heating equipment on the market, and there are a large number of heaters and hair dryers in household equipment. However, if these devices are improperly used, they will cause fire accidents. The main reason is that the internal heat is too high. Especially after the device is turned off, there is still a high dangerous temperature in the device, which will ignite the surrounding combustibles and cause a fire.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the above-mentioned prior art, the present invention proposes a shutdown delay cooling control circuit and a cooling protection method for an electric heating device. After lowering, automatically cut off all the working power of the equipment to avoid fire caused by excessive internal heat.

In order to solve the above-mentioned technical problems, the present invention is achieved through the following technical solutions:

The invention provides a shutdown delay cooling control circuit of an electric heating device, which includes a power supply, an electric heater, a fan, a delay circuit and a delay control circuit, wherein,

When the electric heating device is turned on, the power supply is connected to the electric heater and the fan to supply power to the electric heater and the fan;

When the electric heating device is turned off, the power supply is disconnected from the electric heater, the power supply is connected to the delay circuit, and the delay circuit is connected to the delay control circuit. When the time of the delay circuit reaches a preset time, the delay control circuit controls the power supply to disconnect from the fan.

Preferably, the delay control circuit includes: a first relay, a second relay, a first relay normally open switch A, a first relay normally open switch B and a second relay normally closed switch, wherein,

The first relay is connected in series with the normally closed switch of the second relay, and the normally closed switch of the first relay and the second relay is connected in parallel with the fan;

the second relay is the load of the delay circuit;

The first relay normally open switch A is connected in series between the power supply and the fan;

The first relay normally open switch B is connected in series between the power supply and the delay circuit;

When the electric heating device is turned on, the first relay is in an immediate suction and hold state, and the second relay is in a release state;

When the electric heating device is turned off and the time of the delay circuit does not reach the preset time, the first relay is in a pull-in state, and the second relay is in a release state;

When the electric heating device is turned off and the time of the delay circuit reaches the preset time, the second relay is in a pull-in state, and the first relay is in a release state.

Preferably, the electric heating device shutdown delay cooling control circuit further includes: a power indicator light, connected in parallel with the fan; when the fan is turned on, the power indicator light is on, and when the fan is disconnected, the power The indicator light is off.

Preferably, a power transformer is also arranged between the power supply and the delay circuit,

Preferably, a rectifier is further arranged between the power transformer and the delay circuit.

Preferably, a voltage stabilizer is further arranged between the rectifier and the delay circuit.

Preferably, the preset time of the delay circuit is adjustable.

The present invention also provides a shutdown delay cooling protection method for electric heating equipment, which includes the following steps:

S11: The electric heating device is turned off, the electric heater stops working, and the fan continues to work;

S12: After the delay reaches the preset time, the fan stops working.

Preferably, the step S12 further includes: when the fan stops working, the power indicator light is off.

Compared with the prior art, the present invention has the following advantages:

(1) In the electric heating equipment shutdown delay cooling control circuit and cooling protection method provided by the present invention, after shutdown, the electric heater is only powered off immediately, and the fan is powered off after a delay of working for a period of time. After the temperature is lowered, all the working power of the equipment will be automatically cut off to avoid fire caused by excessive internal heat;

(2) The delay control circuit of the present invention utilizes two relays to automatically control the power-off of the fan according to the preset time of the delay circuit, thereby realizing full automation.

Of course, it is not necessary for any product embodying the present invention to achieve all of the advantages described above simultaneously.

Description of drawings

Embodiments of the present invention are further described below in conjunction with the accompanying drawings:

FIG. 1a is a schematic diagram 1 of a control circuit of a shutdown delay cooling control circuit of an electric heating device according to an embodiment of the present invention;

Fig. 1b is a schematic diagram 2 of a control circuit for a shutdown delay cooling of an electric heating device according to an embodiment of the present invention;

2 is a flow chart of the startup of the electric heating device according to the embodiment of the present invention;

FIG. 3 is a flow chart of the shutdown of the electric heating device according to the embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following implementation. example.

Example 1:

This embodiment describes in detail the shutdown delay cooling control circuit of the electric heating device of the present invention, which includes: a power supply, an electric heater RJ, a fan F, a delay circuit U2 and a delay control circuit, wherein, when the electric heating device is turned on, , the power supply is connected to the electric heater and the fan to supply power to the electric heater and the fan; when the electric heating device is turned off, the power supply is disconnected from the electric heater, the power supply is connected to the delay circuit, and the delay circuit is connected to the delay control circuit , when the time of the delay circuit reaches the preset time, the delay control circuit controls the power supply to disconnect from the fan.

The following will be described with reference to specific examples. In this embodiment, the delay control circuit includes: a first relay KA1, a second relay KA2, a first relay normally open switch A KA1-1, a first relay normally open switch B KA1-2 and The second relay normally closed switch KA2-1, wherein the first relay KA1 is connected in series with the second relay normally closed switch KA2-1, the first relay KA1 and the second relay normally closed switch KA2-1 are connected in parallel with the fan; the second relay KA2 It is the load of the delay circuit U2; the first relay normally open switch A KA1-1 is connected in series between the power supply and the fan F; the first relay normally open switch B KA1-2 is connected in series between the power supply and the delay circuit U2; When the heating device is turned on, the first relay KA1 is in an immediately connected state, the first relay normally open switch A KA1-1 and the first relay normally open switch B KA1-2 are in an immediately closed state, the second relay KA2 is in a released state, and the The second relay normally closed switch KA2-1 is in the normally closed state; when the electric heating device is turned off and the time of the delay circuit U2 does not reach the preset time, the first relay KA1 is in the pull-in state, and the first relay normally open switch A KA1 -1 and the first relay normally open switch B KA1-2 are in the pull-in state, the second relay KA2 is in the release state, the second relay normally closed switch KA2-1 is in the normally closed state, and the fan F continues to work; when the electric heating device is turned off , and when the time of the delay circuit reaches the preset time, the second relay KA2 is in the pull-in state, the second relay normally closed switch KA2-1 is in the off state, the first relay KA1 is in the release state, and the first relay switch A KA1 -1 and the normally open switch B KA1-2 of the first relay are in the normally open state, and the fan F stops working. The circuit schematic diagram is composed of Figures 1a and 1b, the power supply is 220V AC, and the power switch S1 of the power supply is a double-pole double-throw switch, including S1-1 and S1-2. When the power is turned on, both S1-1 and S1-2 are on. state, supply power for electric heater RJ and fan F, when shutdown, S1-1 and S1-2 are in the off state, at this time S1-1 turns on delay circuit U2 and fan F, fan F continues to work, S1-2 Disconnect the power supply of the electric heater RJ, and the electric heater RJ stops working; the delay circuit U2 is set with a preset time, which can be adjusted as needed. When the preset time is not reached, no signal is output to the second relay KA2, The fan F is still powered on and continues to work to dissipate the waste heat in the equipment. When the preset time is reached, the delay circuit U2 outputs a signal to the second relay KA2, the second relay KA2 pulls in, and the corresponding second relay When the normally closed switch KA2-1 is disconnected, the coil of the first relay KA1 connected in series with it is in a released state, the first relay normally open switch A KA1-1 and the first relay normally open switch B KA1-2 corresponding to the first relay In the normally open state, that is, the power supply of the fan F and the delay circuit U2 is disconnected, the fan F stops working, and all the equipment stops working at this time, that is, the real shutdown is realized.

In this embodiment, both ends of the fan F are also connected with a power indicator light D1 in parallel to indicate the working state of the fan F. When the fan F is working, the power indicator light D1 is on, and when the fan F stops working, the power indicator light D1 is off.

In this embodiment, a power transformer T1 is also connected between the power supply and the delay circuit U2, which is used to reduce the 220V alternating current to a low AC voltage, and a rectifier Q is also connected between the power transformer T1 and the delay circuit U2, which is used to convert The alternating current is converted into direct current; further, a voltage stabilizer U1 is connected between the rectifier Q and the delay circuit U2 to ensure the voltage stability of the delay circuit U2; here the delay circuit U2 adopts NE555.

In different embodiments, depending on the voltage of the power supply and the voltage required by the delay circuit U2, the power transformer T1, the rectifier Q and the voltage regulator U1 may not be provided, and these are not necessary components.

Example 2:

The present embodiment describes in detail the protection method for time-delayed cooling at shutdown of the electric heating device of the present invention. It shows that when starting up, S1-1 of the power switch is turned on, the fan F starts to work, the first relay KA1 is in the pull-in state, and the power indicator D1 is on; at the same time, S1-2 is turned on, and the electric heater RJ starts to heat. The shutdown process of the electric heater is shown in Figure 3. When it is turned off, S1-2 is turned off, and the electric heater RJ stops working and heating; at the same time, S1-1 is turned off, the power is turned on through the KA1-2 switch, and the delay circuit U2 starts timing ( The preset time here is set to 50S, in different embodiments, it can be set as needed), when it does not reach 50S, KA1-1 is turned on, the fan F continues to work, KA1 is pulled in, and the power indicator D1 is on. At 50S, KA2 is closed, and its corresponding KA2-1 is disconnected, the coil of KA1 is released, and its corresponding KA1-1 is disconnected, the fan F stops working, the power indicator D1 is off, and KA1-2 is also disconnected, delaying The circuit is de-energized.

Only preferred embodiments of the present invention are disclosed herein, and the present specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, rather than limiting the present invention. Any modifications and changes made by those skilled in the art within the scope of the description should fall within the protection scope of the present invention.

Claims (8)

1. an electric heating equipment shutdown delay cooling control circuit, is characterized in that, comprises: power supply, power switch S1, electric heater, fan, delay circuit and delay control circuit, wherein, The power switch S1 is a double-pole double-throw switch, including S1-1 and S1-2; When the electric heating device is turned on, the S1-1 and S1-2 are both in the ON state, so that the power supply is connected to the electric heater and the fan to supply power to the electric heater and the fan; When the electric heating device is turned off, both S1-1 and S1-2 are in an off state, S1-2 is in an off state so that the power supply is disconnected from the electric heater, and S1-1 is in an off state so that the The power supply is connected to the delay circuit and the fan, and the delay circuit is connected to the delay control circuit. When the time of the delay circuit reaches a preset time, the delay control circuit controls the power supply and the delay control circuit. the fan is disconnected; The delay control circuit includes: a first relay, a second relay, a normally open switch A of the first relay, a normally open switch B of the first relay, and a normally closed switch of the second relay, wherein, The first relay is connected in series with the normally closed switch of the second relay, and the normally closed switch of the first relay and the second relay is connected in parallel with the fan; the second relay is the load of the delay circuit; The first relay normally open switch A is connected in series between the power supply and the fan; The first relay normally open switch B is connected in series between the power supply and the delay circuit; When the electric heating device is turned on, the first relay is in an immediate suction and hold state, and the second relay is in a release state; When the electric heating device is turned off and the time of the delay circuit does not reach the preset time, the first relay is in a pull-in state, and the second relay is in a release state; When the electric heating device is turned off and the time of the delay circuit reaches the preset time, the second relay is in a pull-in state, and the first relay is in a release state. 2. The electric heating device shutdown delay cooling control circuit according to claim 1, further comprising: a power indicator light, connected in parallel with the fan; when the fan is turned on, the power indicator light is on, and when the fan is turned on, the power indicator light is on. When the fan is disconnected, the power indicator is off. 3 . The electric heating device shutdown delay cooling control circuit according to claim 2 , wherein a power transformer is further provided between the power supply and the delay circuit. 4 . 4 . The shutdown delay cooling control circuit of an electric heating device according to claim 3 , wherein a rectifier is further provided between the power transformer and the delay circuit. 5 . 5 . The electric heating device shutdown delay cooling control circuit according to claim 4 , wherein a voltage stabilizer is further arranged between the rectifier and the delay circuit. 6 . 6 . The shutdown delay cooling control circuit of an electric heating device according to claim 1 , wherein the preset time of the delay circuit is adjustable. 7 . 7. An electrical heating device shutdown delay cooling protection method, characterized in that it comprises a power supply, a power switch S1, an electric heater, a fan, a delay circuit and a delay control circuit, wherein, The power switch S1 is a double-pole double-throw switch, including S1-1 and S1-2; When the electric heating device is turned on, the S1-1 and S1-2 are both in the ON state, so that the power supply is connected to the electric heater and the fan to supply power to the electric heater and the fan; When the electric heating device is turned off, both S1-1 and S1-2 are in an off state, S1-2 is in an off state so that the power supply is disconnected from the electric heater, and S1-1 is in an off state so that the The power supply is connected to the delay circuit and the fan, and the delay circuit is connected to the delay control circuit. When the time of the delay circuit reaches a preset time, the delay control circuit controls the power supply and the delay control circuit. the fan is disconnected; The delay control circuit includes: a first relay, a second relay, a normally open switch A of the first relay, a normally open switch B of the first relay, and a normally closed switch of the second relay, wherein, The first relay is connected in series with the normally closed switch of the second relay, and the normally closed switch of the first relay and the second relay is connected in parallel with the fan; the second relay is the load of the delay circuit; The first relay normally open switch A is connected in series between the power supply and the fan; The first relay normally open switch B is connected in series between the power supply and the delay circuit; When the electric heating device is turned on, the first relay is in an immediate suction and hold state, and the second relay is in a release state; Include the following steps: S11: The electric heating device is turned off, the electric heater stops working, and the fan continues to work; S12: After the delay reaches the preset time, the fan stops working; Step S12 further includes: When the electric heating device is turned off and the time of the delay circuit does not reach the preset time, the first relay is in a pull-in state, and the second relay is in a release state; When the electric heating device is turned off and the time of the delay circuit reaches the preset time, the second relay is in a pull-in state, and the first relay is in a release state. 8 . The method for protecting the electric heating equipment for cooling off with time delay according to claim 7 , wherein the step S12 further comprises: when the fan stops working, the power indicator light is turned off. 9 .

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