The U.S. Type 808 bellows sealed globe control valve is especially suited to applications where the possibility of packing leakage cannot be tolerated. The bellows form a flexible static seal that is virtually leak-free, as long as the integrity of the bellows remains intact. The unit contains a set of backup packing that, in many cases, will allow the valve to continue in service until repairs can be made, should the bellows fail. The bellows are available in two pressure ranges:
The low-pressure bellows fits 1/4 in. (6.4 mm), 1/2 in. (12.7 mm),
3/4 in. (19.1 mm) or 1 in. (25.4 mm) valves and is available in
four materials.
The high-pressure bellows fits 1/2 in. (12.7 mm) through
1 in. (25.4 mm) valves and is rated at 1500 psi for
throttling applications.
NOTE: Consult the factory when using this bellows.
APPLICATIONS
The Type 808 valve is widely used in industrial applications, research, and process plants on liquids, gases, or steam. The statically sealed bonnet makes it especially suited to applications where expensive concentrates are controlled and cannot be allowed to leak. Other applications arise when fugitive emissions must be prevented or when sensitive flow streams must be isolated from the ambient atmosphere. This type of seal performs well in high vacuum service where standard packing is not desired.
