JPH05106879A - Automatic ventilating fan - Google Patents

Abstract

PURPOSE:To prevent a sensor from performing an accurate sensing of indoor environment with an air discharging flow sucked from a suction port of a main body of a ventilating fan during an operation of the ventilating fan in a control circuit case for storing the sensor of a heating and activation type for the automatic ventilating fan. CONSTITUTION:An automatic ventilating fan automatically operated in response to a sensing signal of a smoke sensor 5 for use in sensing an indoor environment, for example, tobacco smoke is constricted to have an air flow prohibiting plate 8 projected downwardly near an opening 7 of a control circuit case 4 having an opening 7 at a part thereof while storing an electronic circuit board 6 having the smoke sensor 5 therein. With such an arrangement, it is possible to prevent the air discharging flow from vigorously passing below the opening 7 of the control circuit case 4, sucking out heat of a smoke sensing element heated inside the control circuit case 4 from the opening 7 and cooling it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic ventilation fan which detects a room environment by a heat activation type sensor and automatically operates based on the detection signal.

[0002]

2. Description of the Related Art A conventional automatic ventilation fan of this type generally has a sensor housed in a control circuit case, the structure of which will be described below with reference to FIGS.

As shown in the figure, inside a box-shaped control circuit case 104 provided in the vicinity of the suction port 102 inside a ventilation fan body 103 having a discharge port 101 on one side and a suction port 102 on the lower surface. Stores an electronic circuit board 106 having a heat-activated smoke sensor 105 for detecting the indoor environment, for example, the concentration of cigarette smoke. Further, inside the smoke sensor 105, a smoke detecting element 107 for converting the smoke density into a resistance value and a heater 108 for heating the smoke detecting element 107 are provided. Then, by heating the smoke detecting element 107 with the heater 108, the resistance value of the smoke detecting element 107 is sensitively changed to a small amount of smoke. In addition, an opening 109 is provided on the lower surface of the control circuit case 104 (in the state of FIG. 4) near the smoke sensor 105 to connect the inside of the control circuit case 104 to the inside of the room. Then, the inside of the control circuit case 104 is made to have almost the same air condition as in the room through the opening 109, and the smoke sensor 105 detects this condition to automatically operate the ventilation fan.

[0004]

In such a conventional control circuit case for an automatic ventilation fan, when the ventilation fan is operated to suck in dirty air in the room from the suction port 102 and discharge it from the discharge port 101 to the outside of the room, control is performed. Circuit case 104 is suction port 1
02, the smoke detecting element 1 in which the air flow of the air sucked from the suction port 102 vigorously passes below the opening 109 and is heated inside the control circuit case 104.
The heat of 07 is sucked out from the opening 109 and the smoke detecting element 1
By rapidly cooling 07, the resistance value of the smoke detection element 107 changes, and there is a problem that the actual smoke concentration cannot be detected accurately.

The present invention is intended to solve the above problems, and a control circuit capable of preventing a sensor from being unable to accurately detect the atmosphere in a room due to the airflow of air sucked from the suction port during operation of a ventilation fan. An object is to provide an automatic ventilation fan provided with a case.

[0006]

In order to achieve the above object, the present invention provides an electronic circuit board provided with a heating activation type sensor for detecting the indoor environment, which is provided in the vicinity of a suction port of a ventilation fan body. An airflow blocking plate protruding outward is provided in the vicinity of the opening of a control circuit case having a part of the opening, and an automatic ventilation fan that automatically operates based on a detection signal of the sensor is configured.

[0007]

According to the present invention, when the ventilation fan is operated to suck the dirty air in the room through the suction port and discharge the air out of the room through the discharge port, the exhaust flow is blocked near the opening of the control circuit case. Since it is blocked by the plate and does not vigorously pass under the opening, the actual smoke concentration can be accurately detected without rapidly cooling the smoke detection element.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

As shown in the figure, inside a box-shaped control circuit case 4 provided in the vicinity of the suction port 2 inside a ventilation fan body 3 having a discharge port 1 on one side surface and a suction port 2 on the lower surface. Is
An electronic circuit board 6 having a heat-activated smoke sensor 5 for detecting the concentration of smoke generated in the room is housed. Then, inside the smoke sensor 5, a smoke detecting element for converting the smoke density into a resistance value and a heater for heating the smoke detecting element are provided. An opening 7 is provided on the lower surface of the control circuit case 4 in the vicinity of the smoke sensor 5 so that the inside of the control circuit case 4 communicates with the room. An airflow blocking plate 8 protruding downward is provided near the opening 7 of the control circuit case 4.

In the above structure, smoke such as cigarette is generated indoors, and the smoke is guided into the control circuit case 4 through the opening 7 of the control circuit case 4. Then, the smoke sensor 5 detects the smoke and operates the ventilation fan, sucks the dirty air in the room from the suction port 2 and discharges it from the discharge port 1 to the outside of the room. At this time, the exhaust flow is blocked by the airflow blocking plate 8 provided in the vicinity of the opening 7 of the control circuit case 4 and does not vigorously pass below the opening 7, so that it is heated inside the control circuit case 4. The heat of the smoke detecting element is not sucked out from the opening 7 to be cooled, and the actual smoke concentration can be accurately detected without the smoke detecting element being rapidly cooled.

In the embodiment, the heat activation type sensor for detecting the indoor environment is a smoke sensor, but it goes without saying that the heat activation type sensor is not limited to the embodiment. .

[0012]

As is apparent from the above embodiments, according to the present invention, the airflow blocking plate for blocking the flow of the airflow is provided in the vicinity of the opening of the control circuit case. It is possible to provide an automatic ventilation fan that prevents the sensor from being unable to accurately detect the indoor environment due to the inhaled exhaust flow and performs appropriate automatic operation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an automatic ventilation fan according to an embodiment of the present invention.

FIG. 2 is a perspective view of a control circuit case of the same automatic ventilation fan.

FIG. 3 is a perspective view of a conventional automatic ventilation fan.

FIG. 4 is a perspective view of a control circuit case of the same automatic ventilation fan.

FIG. 5 is a schematic configuration diagram of a smoke sensor housed in the control circuit case.

[Explanation of symbols]

 2 Suction port 3 Ventilation fan main body 4 Control circuit case 5 Smoke sensor 6 Electronic circuit board 7 Opening 8 Airflow blocking plate

Claims (1)

[Claims] 1. An opening of a control circuit case, which is provided in the vicinity of a suction port of a ventilation fan main body, contains an electronic circuit board provided with a heat activation type sensor for detecting an indoor environment, and has an opening in a part thereof. Providing an airflow blocking plate protruding outward in the vicinity,
An automatic ventilation fan that operates automatically based on the detection signal from the sensor.