Quiz Flashcards
The difference between the actuating pressure setpoint and the pressure at which the safety valves resets is called
Blowdown
True or False. Flow to lift check valves must always enter below the seat
True
_____ posses many advantages over gate ,globe, plug, and ball valves, especially for large applications. Savings in weight, space and cost are the most obvious advantages. The maintenance costs are usually low because there are a minimal number of moving parts and there are no pockets to trap fluids.
Butterfly Valves
True or False. The lug wafer design, is held in place betweem two pipe flanges by bolts that join the two flanges and pass through holes in the valve’s outer casing
True
The principal parts of the reducing valve are the ____ ; an upward-s earing valve that has a piston on top of its valve stem, an upward-seating auxiliary ( or controlling ) valve, a controlling diaphragm, and an adjusting spring and screw
Main valve
___ are best suited for high pressure and other severe services.
Y-body globe valves
True or False. The gland of the plug valve is equivalent to the bonnet of a gate or globe valve.
True
___ Is a linear motion valve used to stop, start and regulate fluid flow.
Globe Valve
When compared to a gate valve generally yields much ___ seat leakage.
Less
Globe valves can be arranged so that the disk closes against or in the same direction of fluid flow. When the disk closes ___ the direction of flow, the kinetic energy of the fluid impedes closing but aids opening of the valve.
Against
When the disk closes in the ___ direction of flow, the kinetic energy of the fluid aids closing but impedes opening. The characteristic is preferable to other designs when quick-acting stop valves are necessary.
Same
True or False . Glove valves also have drawbacks. The most evident shortcoming of the simple glove is the high head loss from two or more right angle turns of flowing fluid.
True
Drawbacks of ___ valves are large openings necessary for disk assembly, heavier weight than other valves of the same flow rating, and the cantilivered mounting of the disk to the stem.
Globe
Is a one-piece disk with a cut around the perimeter to improve the ability to match error or change in the angle between the seats.
The flexible wedge gate valve
Are of the ball and socket design. These are self-adjusting and self-aligning to both seating surfaces.
Split wedges gate valves
True or False. Valve bonnets, although a necessity for most valves, increase valve size, represent a significant cost portion of valve cost, and area source for potential leakage
True
The internal elemets of a valve are collectively referred to as a ____
Valve’s trim
True or False. The disk provides the capability for permitting and prohibiting fluid flow.
True
True or False. Most valves are names, in part, according to the design of their disks.
True
Provide the seating surface for the disk.
Seat or seal rings
The actuator operates ___ and _____ assembly.
Stem and Disk
True or false. Most valves use some form of packing to prevent leakage
True
The primary pressure boundary of valve
The body
Function simply as a valve covers
Bonnet
A valve is a mechanical device that controls the flow of fluid and pressure _____ a system or process.
Within
A valve controls system or process fluid flow and pressure by performing ____ of the following functions:
-Stopping and starting fluid flow
-Varying (throttling) the amount of fluid flow
-Controlling the direction of fluid flow
-Regulating downstream system or process pressure
- relieving component or piping over pressure
Any
