Backflow prevention device for bathroom air duct

Abstract

A backflow prevention device is connected to a bathroom air duct and includes a case having two opposite gas inlet-end opening and gas outlet-end opening; a gas inlet-end unit and a gas outlet-end unit respectively mounted to and communicating with the gas inlet-end opening and the gas outlet-end opening; and at least one backflow prevention unit mounted in the case. The backflow prevention unit includes a frame and a plurality of baffle plates pivotally mounted in the frame. The baffle plates are arranged in the frame from top to bottom to overlap with each other, and can be pivotally turned only in one way toward the gas outlet-end opening to an open position. Thus, gas in a bathroom is allowed to flow from the gas inlet-end opening to the gas outlet-end opening, while gas with bad odor in a public pipe shaft is prevented from flowing back into the bathroom.

Description

RELATED APPLICATIONS[0001]This application claims priority to Taiwan Application Serial Number 97140022, filed Oct. 17, 2008, which is herein incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to a backflow prevention device, and more particularly to a backflow prevention device for bathroom air duct.BACKGROUND OF THE INVENTION[0003]Apartment dwellings and condominiums usually have bathrooms designed as spaces without any vent directly led to an outdoor environment. With the door thereof being shut, such a bathroom in use forms a closed space almost isolated from the external environment, and any hot air or biogas or other poisonous gases produced in the closed bathroom in use just could not be exhausted but diffuses into the living room, bedrooms or other spaces in the apartment. In some worse conditions, such biogas or poisonous gases would seriously affect the dwellers' health and safety.[0004]To overcome this problem, an extraction fan is usually...

AI Technical Summary

Benefits of technology

[0022]Preferably, a second spacing frame is further provided to locate in the receiving space of the case at one side of the fan unit facing toward the gas outlet-end opening, so that a space is reserved at the second spacing frame to prevent the fan unit from interfering with the backflow prevention unit and ensure smooth operation of the fan unit as well as the backflow prevention unit.

Problems solved by technology

In some worse conditions, such biogas or poisonous gases would seriously affect the dwellers' health and safety.

The gases produced by the bathrooms of all dwellers in the apartment building and collected in the public pipe shaft frequently emit bad odors, which tend to flow from the public pipe shaft back to the bathrooms at different floors of the apartment building.

That is, when the bathroom extraction fans are not in operation, air in the public pipe shaft carrying the bad odor gases can very easily invade into the bathrooms via the air ducts to largely reduce the dwellers' living quality or even bring hazards to the dwellers' physical and mental health.

Such undesirable condition is particularly serious in windy days when strong wind blows down into the public pipe shaft from the roof of the building.

The bad odors will quickly flow back through the air ducts and invades into the bathrooms in all floors.

Further, other bad odors and even poisonous gases, such as smoke from burning cigarettes, carbon monoxide produced by burning charcoal, etc., produced in the bathrooms at some floors will also flow along the public pipe shaft and the air ducts into the bathrooms at other floors to seriously threaten the health and living safety of the dwellers in the apartment building.

Therefore, the conventional bathroom extraction fan and the air ducts connected thereto have poor applicability.

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