Valves & Plumbing 111 Flashcards
What is a valve?
A pressure containing device designed to control the flow of fluid media (liquids, gases, vapors, solids in suspension)
To control a valve means what?
To start, to throttle (regulate), stop and prevent backflow.
What valve prevents backflow?
Check valve
Which valves throttle(regulate) flow?
Globe and Angle Valve
Where did Gate valves get their name?
Ancient castle gates
A gate valve should never be…
Throttled(regulated).
What can happen if you throttle a Gate valve?
Erosion and even vibration and chatter. Can cause damage to the seating surfaces.
What is a globe valves main purpose?
To regulate flow… or used when a valve must be frequently open and closed.
Globe valves can be used for….
Hot and Cold water, air, oil, gas, and volatile liquids.
Lift checks are used for
reciprocating pump and air compressor
Swing checks should not be used in a…
rapid cycling system
Two hole up valve means
Level up two bolts
SWP =
Steam Working Pressure
CWP =
Cold Working Pressure
WOG =
Water Oil Gas
PSIG =
Pressure Square Inch Gauge
Solenoid Valve is used on
Gas lines
What valve has a resiliant seat to protect from corrosion?
Butterfly valve.
Circuit Balancing valve does what?
Ensures designed flow rate is achieved regardless of drop in system pressure.
A ball valve comes in how many pieces?
Three
Corporation cock is joined on each side by
IPS(Iron Pipe Size) by Flare
Curb cock connected on each by
Flare by Flare
What is a rated valve?
A valve that is rated for a certain amount of PSI for WOG or SWP
If a valve is not rated then the PSI is….
125 PSI WOG & O PSI WSP
What gives Gas its smell?
Mercaptan
Gas cock is joined on each side by
IPS by IPS
Backwater valve on a floor drain does what?
Allows water to come down but prevents it from coming back up
Plug valves need to be how far under frost level?
Six Inches
How deep is the frost level?
36 inches/3 feet
Every gas line needs what?
A shutoff
What position should valves be installed?
Upright
What do you need for a compression fitting?
Nut and ferrule
OSY(Outside Screw Yoke) for gate valve makes…
the handle rise with the gate
Constant flow over the valves disc causes
pitting and creates difficult positive shutoff (Wiredrawling)
The vent is always closet to what?
The house
The Cleanout is always closet to what?
The curb
All fixtures need to be what?
Trapped and vented
