Valves Flashcards
What are the applications for valves?
Starting and stopping flow
Regulating or throttling flow
Preventing reverse flow
Regulating pressure
Relieving pressure
Isolating circuits or components
What are the valve materials?
Bronze
Cast iron
Malleable iron
Steel
Stainless steel
What materials are used for the valve packing?
Teflon
Teflon-impregnated asbestos
Graphite-impregnated asbestos
Semi-metalic packing
Metal wire re-enforced
What markings must be present when selecting a valve?
Manufacturers name and trademark
Service ratings
Material type
CSA markings
What does WOG mean on a valve?
Water, oil, Gas
What does CWP Stand for?
Cold working pressure
What does WSP on a valve mean?
Working steam pressure
Where will you find flange connections most likely?
Larger valves
Are welded fittings suitable for high temp and high pressure?
Yes
But should not be used where dismantle may be necessary
Where are soldered connections used?
Low pressure low temperature
What is the most common joint?
Threaded
What are gate valves used for?
Full flow or no flow.
Do not use for throttling
Where would you find plug valves?
Gas supply lines
Low pressure steam line
Water treatment
Pulp paper and chemical industries
Ball valves were deigned for on/off valves. Can they be used to throttle?
Yes
What are some benefits of butterfly valves?
Low pressure drop across fully opened valve
Easy to operate
Relativity light weight
Compact
Often used for throttling
Where are needle valves used?
Where precise fluid flow needs to be achieved
This valve is used for throttling and regulating flow but has much more resistance to flow then a gate valve?
Globe valve
Angle valve is the same operating principle as a _______ valve?
Angle valve
What is different about balance valves then globe valves?
Require much less force to operate
When are diaphragm valves used?
For throttling corrosive and toxic materials
When would you use a check valve?
When you don’t want the fluid to flow back words when pressure is off.
What is the purpose of a over pressure relief valve?
To prevent equipment damage and protect workers
What is a pressure safety valve for?
Provide rapid means of getting rid of excess pressure in piping . Use with compressible gases and steams
