JPS5819945B2 - ventilation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention 1 relates to a ventilation system in which the rotational speed of a drive motor that rotationally drives the ventilation blades is varied so that the amount of air blown by the ventilation blades is always substantially constant.

2. Description of the Related Art Conventionally, a ventilation fan for discharging dirty air from a room to the outside has been configured so that a drive motor rotates a blower blade at a constant speed to achieve a predetermined exhaust capacity.

However, depending on the exhaust conditions such as the presence or absence of an intake port in the room, the opening/closing status of windows, or the presence or absence of an exhaust duct, pressure loss due to the air blower may occur. However, if the exhaust conditions differ, the amount of air blown by the air blower blades will decrease due to the pressure loss, making it impossible to achieve the desired exhaust capacity and requiring a longer exhaust time.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to detect the amount of air blown by the air blower blade and control the rotational speed of the drive motor that rotationally drives the air blower blade so that the air flow rate remains approximately constant at all times. It is an object of the present invention to provide a ventilation device that can always exhibit a substantially constant exhaust capacity even under different exhaust conditions by having a configuration in which a circuit is provided.

An embodiment in which the present invention is applied to a range hood will be described below with reference to the drawings.

First, the schematic configuration will be explained with reference to FIG.

Reference numeral 1 denotes a main body in which a cover 3 is attached with screws 4 to the lower opening of a flat container-shaped hood 2 having an open bottom, and a cover 3 is attached to the lower opening of the hood 2 with screws 4 so as to close the opening. An indoor opening 6 is formed to open the hood 2.
An outdoor opening 7 is formed on the outer surface of the back plate 2 a of the hood 2 , and an exhaust port body 8 communicating with the outdoor opening 7 is attached to the back plate 2 a of the hood 2 . Attach guard 9 in a manner that corresponds to

Reference numeral 10 denotes a drive motor attached to the inner surface of the top plate 2b of the hood 2 via a mounting frame 11, with its rotating shaft 10a protruding downward, and a large number of blades 12b mounted on a base plate 12a at its protruding end. A cylindrical blower blade 12 is fitted and fixed in a manner corresponding to the indoor opening 6, thereby configuring a sirocco fan 13 as a blower.

A partition plate 14 has an upper end attached to the inner surface of the top plate 2b of the hood 2, and together with the hood 2 and the cover 3, forms a swirl chamber 15 of the sirocco fan 13.

Reference numeral 16 denotes a substantially arc-shaped opening/closing plate disposed within the exhaust port body 8, whose upper end, which is the base end, is pivoted to the side plate 8a of the exhaust port body 8 so as to be pivotable in the vertical direction. .

The opening/closing plate 16 normally rotates downward due to its own weight to close the outdoor opening 7, and when it receives the air pressure from the air blower blades 12, it rotates upward to close the outdoor opening 7. The outer opening 7 is opened.

Reference numeral 17 denotes a control circuit 1 which is mounted on the inner surface of the side plate 8a of the exhaust port body 8 and located inside the opening/closing plate 16.
8 is a power switch attached to the inner surface of the front plate 2c of the hood 2.

The main body 1 constructed in this way is placed above a heat source (not shown), such as a gas range, and the exhaust port body 8 is connected to the chamber 5.
while inserting it into the insertion hole 20 formed in the wall 19 of the
The exhaust port body 8 is connected to, for example, a centralized exhaust duct (not shown) by an exhaust duct 21.

Now, the configuration of the electric circuit will be described with reference to FIG.

Reference numerals 22 and 23 are power terminals connected to a 10 o volt pole-phase AC power source (not shown), and one of the power terminals 22 is connected to the input terminal 2 of the control circuit 17 via the drive motor 10.
4 and 25, and the other power supply terminal 23 is connected to the other input terminal 25 via the power switch 18.

In detail, the control circuit 17: 26
is a full-wave rectifier circuit formed by bridge-connecting four diodes 26a to 26d, whose AC input terminals are connected to the input terminals 24 and 25, respectively, and whose DC output terminal is connected to the bus bar 27.
and 28, respectively, and these busbars 27 and Schiff 8
A thyristor 29 of the illustrated polarity is connected between the busbars 27 and 27.
A series circuit of a variable resistor 30, a thermistor 31 with a negative characteristic as an airflow detection element, and a capacitor 32 is connected between and connected to the gate of the thyristor 29.

Next, to explain the operation of this embodiment with the above configuration, it is assumed that a gas range is being used as a heat source in the room 5, and that the temperature inside the main body 1 above it is high. It is assumed that window 5 (not shown) is open.

Now, when the power switch 18 is closed to start the exhaust operation, the AC power voltage applied between the power terminals 22 and 23 is transferred to the AC power terminal of the full-wave rectifier circuit 26 via the 1 drive motor 10. The voltage is then rectified by the full-wave rectifier circuit 26 and applied between the buses 27 and 28 as a full-wave rectified DC voltage.

Therefore, the capacitor 32 is charged via the variable resistor 30 and thermistor 31, but the thermistor 31
The capacitor 32 senses the high temperature inside the capacitor 32 and exhibits a low resistance value due to self-heating caused by the flow of current.
The voltage across the terminals quickly reaches the operating voltage of the voltage regulator diode 33.

As a result, the constant voltage diode 33 becomes conductive and a gate current flows through the thyristor 29, so the thyristor 29 becomes conductive at the maximum conduction angle, and substantially the entire AC power supply voltage is supplied to the drive motor 10. The blower blades 12 are rotated at the maximum speed to blow air from the indoor opening 6 to the outdoor opening 7 with the maximum amount of air, and the opening/closing plate 16 is rotated upward by the blowing pressure. Open the outdoor opening 7.

Therefore, the dirty air in the room 5 is released from the indoor opening 6. Vortex chamber 15. Outdoor opening 7. The air is exhausted to the outside through the exhaust port body 8, the exhaust duct 21, and a central exhaust duct (not shown).

On the other hand, when the blower blade 12 begins to rotate at the maximum air flow rate, the high temperature air inside the main body 1 is discharged and the thermistor 31 is cooled by the air blown by the blower blade 12. As the temperature decreases, its resistance increases.

As a result, the charging speed of the capacitor 32 is slowed down, and the conduction angle of the thyristor 29 is also reduced.
The voltage supplied to the drive motor 1 becomes substantially lower.
The rotational speed of 0 changes to become slower, and the amount of air blown by the air blower blades 12 decreases.

The degree of self-heating of the thermistor 31 depends on the flowing current, and the degree of cooling depends on the amount of air blown by the blower blades 12, so when the degree of heat generation and the degree of cooling of the thermistor 31 are in equilibrium, the drive motor The variable resistor 30 is set in advance so that the conduction angle of the thyristor 29 is controlled so that the rotational speed of the thyristor 10 becomes a predetermined speed, and at this time, the blower blade 12 is made to exhibit a predetermined exhaust capacity. The amount of air blown becomes a predetermined substantially constant amount.

In such a state, for example, if we consider a case where the window (not shown) of the chamber 50 that was in the open state is closed, even if the drive motor 10 rotates at the predetermined speed, the blower blade 1
Since a pressure loss occurs when the air pump 2 sucks the air in the chamber 5, the amount of air blown decreases.

In this case, the degree of cooling of the thermistor 31 by the air blown by the air blower blades 12 decreases, and the equilibrium between the degree of heat generation and the degree of cooling of the thermistor 31 is broken, and the temperature of the thermistor 31 increases. Resistance value decreases.

Therefore, the charging speed of the capacitor 32 becomes faster, the conduction angle of the thyristor 29 becomes larger, the voltage supplied to the first drive motor 10 becomes substantially higher, and the rotational speed of the drive motor 10 changes to become faster. Then, when the amount of air blown reaches the predetermined substantially constant amount described above so that the air blower blade 12 can exhibit a predetermined exhaust capacity, the degree of heat generation of the thermistor 310 and the degree of cooling are again in an equilibrium state, and the drive motor 10 is activated. The rotation speed is maintained constant.

The above-mentioned operation is similarly performed depending on whether there is an exhaust duct 21 or an air intake port in the chamber 5.

As described above, according to this embodiment, the control circuit 17 having the thermistor 31 that detects the amount of air blown from the air blower blade 12 controls the drive motor 1 so that the amount of air blown is always substantially constant.
Therefore, the air blowing by the blower blades 12 varies depending on the exhaust conditions such as the opening/closing status of the window of the chamber 5, the presence or absence of an intake port in the chamber 5, or the presence or absence of the exhaust duct 21. Even if a pressure loss occurs, a predetermined, substantially constant exhaust capacity can always be achieved, and there is no problem such as an increase in exhaust operation time.

Although the above embodiment is a case in which the present invention is applied to a range hood, the present invention is not limited to this and can be applied to ventilation devices in general.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and may be modified as appropriate without departing from the scope of the invention, for example, the control circuit 17 may be provided in the indoor opening 6. Of course, it can be implemented.

As described above, the present invention can provide a ventilation system that exhibits an excellent effect of being able to always exhibit a substantially constant exhaust capacity even under different exhaust conditions.

[Brief explanation of drawings]

The drawings show an embodiment in which the present invention is applied to a range hood, with FIG. 1 being a longitudinal sectional side view and FIG. 2 being an electric circuit diagram. In the drawings, 1 is a main body, 2 is a hood, 3 is a cover, 6 is an indoor opening, 7 is an outdoor opening, 10 is a drive motor, and 12
is a blower blade, 13 is a sirocco fan, 17 is a control circuit,
18 is a power switch, and 31 is a thermistor (airflow detection element).

Claims (1)

[Claims] 1. A main body having an indoor opening and an outdoor opening, a drive motor provided in the main body, and a blower blade that is rotationally driven by the drive motor and blows air from the indoor opening to the outdoor opening. A ventilation device comprising: an air volume detection element that detects the amount of air blown by the air blower; and a control circuit that changes the rotational speed of the drive motor so that the amount of air blown is substantially constant.