JPS5856500Y2 - Operation control device for ventilation fans, etc. - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improved configuration of a ventilation fan that detects the temperature difference between the upper and lower parts of a room and automatically starts operating when the sensed temperature reaches a certain value.

When you use a microwave, etc., the temperature difference between the top and bottom of the room increases, so if you operate the ventilation fan when the temperature difference exceeds a certain value and stop it when it falls below a certain value,
The ventilation fan will only run when the range is in use.

However, if the room is preheated,
Since there is a temperature difference before you use the range, there is a risk that the ventilation fan will start running even when the range is not in use.

To prevent this from happening, it is common practice to make it possible to freely set and adjust the temperature difference when the ventilation fan starts operating.

However, even if the temperature difference at the start of operation is adjusted, the gap between the temperature difference at the start of operation and the temperature difference at the time of stopping operation is kept constant, which has the disadvantage that chattering is likely to occur while the ventilation fan is operating. there were.

This will be explained based on FIG. 2. FIG. 2A shows a change curve of temperature difference with respect to time when there is no temperature difference between the top and bottom of the room before using the microwave.

In other words, when you start using the microwave, the temperature difference between the top and bottom begins to increase, resulting in a temperature difference T.

The ventilation fan will start operating when the

When the ventilation fan is operated, the temperature difference decreases a little, and then maintains a substantially constant temperature difference.

When the range is no longer used at time t2, the temperature difference further decreases, and when the temperature difference reaches T5, the operation of the ventilation fan is stopped.

The situation in Figure 2 is when the room is heated and there is a temperature difference between the top and bottom of the room even before the microwave is used.

In this case, the temperature difference T when the ventilation fan starts operating.

is set higher than in the case of Fig. 2A. When you start using the microwave in this state, the temperature difference between the top and bottom of the room will be T.

When this happens, the ventilation fan starts operating and the temperature difference begins to decrease.

However, the temperature difference is T. Because of this setting, when the ventilation fan starts operating, the temperature difference between the upper and lower sides becomes smaller rapidly than in the case shown in Fig. 2A, and the temperature difference Ts at which the operation of the ventilation fan is immediately stopped is reached.

The ventilation fan then stops, but since the range is still in use, the temperature difference increases again, resulting in a temperature difference of T.

When this happens, the ventilation fan will start operating again.

In this way, the set temperature difference T. If the value is increased, the ventilation fan may repeatedly start and stop in a short period of time, causing so-called chattering, which may shorten its lifespan.

So the temperature difference is T.

When set to a large value, this temperature difference T.

It is necessary to widen the difference between T and the temperature difference T when the ventilation fan stops.

Figure 2 C shows the temperature difference T.

This shows a temperature difference change curve when the difference between T5 and T5 is increased, and in this case, no chattering occurs.

The purpose of this proposal is to provide a control device that prevents the ventilation fan from chattering.The explanation will be given below based on Figure 1. 1 is the fan motor of the ventilation fan, and the rectifier circuit 2 consists of four diodes. Semiconductor elements with control poles are connected in series through the .

4 is a smoothing capacitor, and 5 is a constant voltage diode.

Also, 6 is a thermistor that detects the temperature at the bottom of the room, and 7 is a thermistor that detects the temperature above the heat source. Both thermistors are connected in series, and a semi-fixed resistor 9 is connected to the connection point 8, and the movable contact piece is connected to the thermistor 6. It is connected to the base side of the transistor 10.

Reference numeral 11 designates the other transistor that constitutes a Schmitt circuit together with the one transistor 10, and a variable resistor 12 for sensitivity adjustment is connected to a common portion of the emitter circuits of both transistors.

13 is a transistor for amplifying the output signal of the Schmitt circuit and applying the signal to the control pole of the semiconductor element 3 with a control pole; 14 is a capacitor for preventing malfunction due to noise.

The operation of the above configuration will be explained below.

If the temperature detected by the thermistor 6 that detects the temperature at the bottom of the room and the thermistor 7 above the heat source is not that different because the range is not in use, the potential at the connection point 8 is set to be relatively high, so the transistor The base voltage of 10 is high, so this transistor is non-conducting.

As a result, the other transistors 11 and the amplifier transistor 13 constituting the Schmidts I circuit become conductive, and no current flows through the control pole of the semiconductor element 3 with a control pole, so that the semiconductor element 3 is non-conductive. , since no current flows through the fan motor 1, it does not rotate.

When the range is in use, a thermistor 7 above the heat source detects the temperature and reduces the resistance.

As a result, the potential at the connection point 8 decreases, the transistor 10 becomes conductive, the transistor 11 and the amplifier transistor 13 become non-conductive, and the control electrode semiconductor element 3 becomes conductive, causing current to flow to the fan motor 1, causing the motor to rotate. The ventilation fan is operated.

When the range is stopped, the thermistor 7 above the heat source
Since the temperature difference detected by the thermistor 6 at the lower part of the room becomes small again, the potential at the connection point 8 becomes high, and as in the case described above, no current flows to the fan motor 1, and it stops.

Note that if the temperature detected by the thermistor 7 above the heat source is somewhat high even when heating is being performed and the range is not in use, the resistance value of the sensitivity adjustment variable resistor 12 is increased.

Then, the emitter potential of transistor 10 decreases, so
1 range, unless the potential at connection point 8 drops considerably.
10 does not switch to conduction.

Therefore, the ventilation fan will not be operated unless the temperature detected by the thermistor 7 above the heat source becomes considerably high and its resistance value becomes sufficiently small.

That is, the temperature difference T at the start of operation.

can be set high.

On the other hand, the Schmitt circuit has hysteresis characteristics due to various reasons such as the difference in the size of the resistors 15 and 16, and the temperature difference T detected by both thermistors 6 and 7 when the ventilation fan starts operating.

There is a gap between the detected temperature difference T8 and the detected temperature difference T8 at the time of stopping.

Also, as a result of the analysis, the temperature difference T at the start of operation was determined by increasing the variable resistor 12 for sensitivity adjustment connected to the common part of the emitter circuits of both transistors 10 and 11.

When set to a large value, this temperature difference T.

It has become clear that the difference between T8 and the temperature difference T8 when the ventilation fan stops increases, and this was also confirmed through experiments.

Therefore, the temperature difference T at the start of operation is determined by the variable resistor 12.

When T is made high, the difference from the temperature difference T5 at the time of stopping the operation becomes large, and the occurrence of chattering is prevented.

As described above, in the present invention, since the variable resistor 12 for sensitivity adjustment is connected to the common part of the emitter circuit of the two transistors 10 and 11 that constitute the Schmitt circuit, the temperature difference T when the ventilation fan starts operating.

can be freely set, and at the same time the temperature difference T.

When set to a large value, the temperature difference T5 when the ventilation fan stops
The ventilation fan can automatically widen its opening, prevent chattering, and extend the life of the ventilation fan.

The present invention can be used not only for ventilation fans but also for circulators, etc.

[Brief explanation of drawings]

Figure 1 is an electrical circuit diagram of the proposed device, and Figure 2 is a graph showing changes in the temperature difference between the top and bottom of the room. If there is a difference, and the temperature difference between the temperature difference when the ventilation fan starts and the temperature difference when it stops is small, case C is a case where the difference is large. 6...Thermistor that detects the temperature in the lower part of the room,
7...Thermistor that detects the temperature above the heat source,
10゜11...Transistor forming the Schmitt circuit, 1...Fan motor, 12...
...Variable resistor for sensitivity adjustment.

Claims (2)

[Scope of utility model registration request] (1) In a device that detects the temperature above and below the room using two thermistors, uses the temperature difference as an input signal to the Schmitt circuit, and controls the stoppage of the fan motor using the output signal, the above-mentioned Schmitt circuit An operation control device for ventilation fans, etc., in which a variable resistor for temperature-sensitive adjustment is connected to the common part of the emitter circuits of two transistors that make up the system. (2) An operation control device for a ventilation fan or the like as set forth in claim 1 of the utility model registration claim, which comprises a thermistor provided above the heat source to detect the temperature above the room.