Search results
Results from the WOW.Com Content Network
An isolation valve is a valve in a fluid handling system that stops the flow of process media to a given location, usually for maintenance or safety purposes. [1] They can also be used to provide flow logic (selecting one flow path versus another), and to connect external equipment to a system. [ 2 ]
Two block valves and a bleed valve are as a unit, or manifold, to be installed for positive isolation. Used for critical process service, DBB valves are for high pressure systems or toxic/hazardous fluid processes. Applications that use DBB valves include instrument drain, chemical injection connection, chemical seal isolation, and gauge isolation.
The quantity of bleed air flowing to the AC pack is regulated by the flow control valve (FCV). One FCV is installed for each PACK. A normally closed isolation valve prevents air from the left bleed system from reaching the right PACK (and vice versa), although this valve may be opened in the event of loss of one bleed system.
A second function of the PCV valve is to act as a flame arrester and to prevent positive pressure from the intake system from entering the crankcase. This can happen on turbocharged engines or when a backfire takes place, and the positive pressure could damage the crankcase seals and gaskets, or even cause a crankcase explosion. The PCV valve ...
This provides redundancy as well as making the system immune to the single failure of any inboard or outboard valve operator or isolation signal. When an isolation signal is given to a group, both the inboard and outboard valves stroke closed. Tests of isolation logic must be performed regularly and is a part of each plant's technical ...
Valves stop (or regulate) the flow of liquids or gases. They are categorized by application, such as isolation, throttling, and non-return. Isolation valves temporarily disconnect part of a piping system to allow maintenance or repair, for example. Isolation valves are typically left in either a fully open or closed position.
SSD – sub-sea level depth (in metres or feet, positive value in downwards direction with respect to the geoid [citation needed]) SSD – sliding sleeve door; SSFP – subsea flowline and pipeline; SSG – sidewall sample gun; SSH – steam superheater; SSIC – safety system inhibit certificate; SSIV – subsea isolation valve; SSTV ...
Apart from the actuation of shutdown valves and blowdown valves, outputs include isolation of electrical sources, power shutdown, activation of fire pumps, etc. ESD is usually activated when a loss of containment and/or a fire is detected, although it may be activated at any time the plant operators feel it is necessary to preserve life, assets ...