Valves Flashcards
Primary function of valves is too
Control flow
What valve provides minimal pressure loss or turbulence
Gate valve
What valve is not recommended to throttle
Gate Valve
What design of gate valve is most common
Solid wedge
What gate valve design is less prone to chatter
Solid wedge
What gate valve design may stick with varying temp and is not well suited to compensate for distortions
Solid wedge
What gate valve design has two separate wedge halves
Split wedge
What gate valve design has 2 discs mounted on either side of spreading device
Double disc
What gate valve design is the most expensive but can take the most seat misalignment
Double disc
Globe valves are _____
Directional
Preferred valve when throttling flow
Globe Valve
A local water flow alarm is required on sprinkler systems with more then
20 sprinklers
The fire department connection size can be
Minimum of 2 1/2 but must be at least the size of the largest riser being served
FDC’s are required to be how far above ground
18-48”
Larger systems, water must be delivered in how much time to ITV
60 seconds
PIV must be installed so the top of the post is _______ above grade
32” to 40”
What globe design has max resistance to corrosion
Plug disc
Short tapered disc, metal on metal contact
Conventional disc
Flat soft disc against the seat in the valve body
Composition disc
Sharp point that controls flow through seat, excellent for throttling
Needle valve
What globe design is most common in sprinklers
composition disc
Best suited where a 90 bend is required
Angle valve
Thread design easiest to tell if open or closed
Rising stem with outside screw
Common stem design for angle and globe valves
Rising stem with inside screw
Stem design typically found in gate valves, doesn’t move up or down
Non rising stem with inside screw
Bonnet joint not good for frequent service/light duty
Screwed bonnet
Best bonnet for service, more strength then screwed
Union bonnet
Bonnet that consists of flanged connection with nuts bolts and gaskets
Bolted Bonnet