Fluid handling – Systems – Multi-way valve unit
Patent
1991-08-19
1993-01-26
Rosenthal, Arnold
Fluid handling
Systems
Multi-way valve unit
137238, 251315, F16K 506
Patent
active
051815397
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a ball valve not having portions thereof at which liquids stagnate when the valve is opened, to thus prevent the breeding of bacteria therein.
BACKGROUND ART
Conventionally, in transport lines for liquids in the semiconductor industry, bio and medical industries, food industry, and other chemical industries, use has been made of ball valves comprised of balls provided in the valve chests and gripped by seat carriers fitted with seat rings, and pocket-less ball valves comprised of balls arranged rotatably in a casing formed with a spherical space inside so as not to form pockets therein.
In these conventional ball valves, when the valves were left open to pass the fluid therethrough for long periods, the connection between the space formed between the valve chest and the ball and the passage of the liquid is completely shut, whereby the liquid sealed in the space becomes completely dead (stagnant), and thus it becomes impossible to prevent a proliferation of bacteria, etc.
Further, a pocket-less ball valve has a large rotational torque, since substantially the entire ball surface serves as a sliding part, but to ensure a smooth operation thereof, the machining precision of the ball and the spherical space must be very strict. Further, from a micropoint of view, since sliding parts are used, when water enters therein it becomes impossible to prevent a proliferation of bacteria, etc.
Further, in the conventional ball valve, when the valve is closed, fluid flowing into the valve chest space stagnates, as it is closed off from the ambient atmosphere, and this sometimes causes problems. For example, in the semiconductor industry, hydrogen peroxide water is sometimes flushed through pipes to sterilize the insides of the pipes, but if the ball valve is closed after passing the fluid therethrough, the hydrogen peroxide water sealed in the valve chest is vaporized and the pressure in the valve chest rises, causing problems of cracks in the ball valve body and a breakage of the seat rings.
DISCLOSURE OF THE INVENTION
The present invention was made in consideration of how to resolve the above problems, and an object thereof is the provision of a ball valve which does not have any portions in which liquids can stagnate when the valve is opened, which has a small rotational torque of the valve, and which does not require a special machining precision.
A further object of the present invention is the provision of a ball valve in which absolutely no leakage of fluid occurs when the valve is closed, and no breakage of the ball valve due to stagnant fluid occurs when the valve is closed.
Therefore, according to the present invention, there is provided a ball valve wherein a rotation of a ball provided in a valve chest opens and closes a valve, characterized in that an orifice is provided in a passage of the ball valve and communicating portions are provided to connect the upstream and downstream sides of the orifice and the valve chest space.
According to a preferred embodiment of the present invention, the orifice is provided in the passage in the ball, and the communicating portions are provided upstream and downstream of the passage in the ball.
According to another preferred embodiment of the present invention, the orifice is provided downstream of the passage of the ball, a communicating hole is provided at the approximate center portion of the passage of the ball, which communicates with a groove wherein the flange portion of a stem is fitted, and communicating grooves are provided at the side and bottom portions of the flange, which grooves communicate with the valve chest space.
According to a further embodiment, the orifice is provided in the passage of the ball, the communicating portions positioned upstream of the orifice are provided in a union which is slidably fitted in a valve body, and the communicating portions positioned downstream of the same are provided downstream of the end of the passage of the ball.
According to a still another embodiment, the o
REFERENCES:
patent: 3134405 (1964-05-01), White et al.
patent: 3322149 (1967-05-01), Haenky
patent: 3525352 (1970-08-01), Jensen
patent: 3542337 (1970-11-01), Scaramucci
Asahi Yukizai Kogyo Co. Ltd.
Rosenthal Arnold
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