Patent Application
20090056601
1. Field of the Invention
This invention relates to a furnace, more particularly to a furnace including a safety valve having first and second covering plates pivoted to a shaft.
2. Description of the Related Art
Conventional furnaces are normally provided with a safety outlet for releasing combustion gas during an emergency. Under normal condition, the safety outlet is closed by a safety valve. A conventional safety valve includes a covering plate secured to an inner wall of a gas-releasing stack through a support and securing means. The covering plate is formed with two openings, and has two door portions, each of which is pivoted to the remainder of the covering plate through a shaft for closing and opening a respective one of the openings.
When the furnace is operated in a normal condition, each of the door portions of the covering plate is disposed at a closed position by virtue of its weight so as to prevent the combustion gas from flowing through the safety outlet. On the other hand, when the furnace encounters an emergency, and the pressure therein is abruptly increased, each of the door portions of the covering plate is pushed to open by the high pressure combustion gas, thereby permitting the combustion gas to rush directly through the safety outlet to the atmosphere to prevent gas explosion.
The object of the present invention is to provide a furnace with a safety valve that has a simpler structure than the safety valve of the aforesaid conventional furnace.
According to the present invention, a furnace comprises: a furnace housing defining a combustion chamber therein and having a top end section that is provided with an emergent stack which defines a gas-releasing channel in fluid communication with the combustion chamber; and a safety valve mounted in the gas-releasing channel and including a shaft that is secured to the emergent stack, and opposite first and second covering plates that are pivoted to the shaft so as to be rotatable relative to the shaft for closing and opening the gas-releasing channel.
In drawings which illustrate an embodiment of the invention,
The furnace 2 includes: a furnace housing 21 defining a combustion chamber 210 therein and having a top end section 211 that is provided with an emergent stack 22 which defines a gas-releasing channel 212 in fluid communication with the combustion chamber 210; and a safety valve 4 mounted in the gas-releasing channel 212 and including a shaft 3 that is secured to the emergent stack 22, and opposite first and second covering plates 41, 42 that are pivoted to the shaft 3 so as to be rotatable relative to the shaft 3 for closing and opening the gas-releasing channel 212.
The furnace 2 further includes a pair of positioning studs 51 secured to the emergent stack 22 and protruding into the gas-releasing channel 212 for supporting and retaining the first and second covering plates 41, 42 at a closed position (see FIG. 3), where the first and second covering plates 41, 42 close the gas-releasing channel 212, thereby preventing the combustion gas from flowing therethrough.
In this embodiment, each of the first and second covering plates 41, 42 is substantially semi-circular in shape. The gas-releasing channel 212 has a circular cross-section. The first and second covering plates 41, 42 substantially overlap the circular cross-section of the gas-releasing channel 212 when the first and second covering plates 41, 42 are disposed at the closed position. Preferably, the supporting studs 51 are diametrically disposed relative to the gas-releasing channel 212.
The furnace 2 further includes a pair of stopping studs 52 secured to the emergent stack 22, protruding into the gas-releasing channel 212, and disposed above the supporting studs 51. The first and second covering plates 41, 42 abut against the stopping studs 52, respectively, when the first and second covering plates 41, 42 are disposed at an opened position (see
The furnace 2 further includes a pair of first C-shaped plates 43 and a pair of second C-shaped plates 44. Each of the first and second C-shaped plates 43, 44 has a sleeve portion 431, 441 that is sleeved rotatably on the shaft 3, and two opposite end portions 432, 442 that are secured to a respective one of the first and second covering plates 41, 42.
In operation, the first and second covering plates 41, 42 are supported and retained by the supporting studs 51 at the closed position, and the combustion gas from the combustion chamber 210 is directed to flow through a designated path when the furnace 2 is operated at a normal condition. However, when the furnace 2 encounters an abnormal condition, i.e., the pressure of the combustion gas abruptly increases, the first and second covering plates 41, 42 can be directly pushed by the high pressure combustion gas and are moved to the opened position to release the high-pressure combustion gas.
The furnace 2 of this invention is advantageous in that the safety valve 4 thereof has a simpler structure as compared to the safety valve of the aforesaid conventional furnace.
With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention. It is therefore intended that the invention be limited only as recited in the appended claims.
