Please Define
Cavitation
When a flowing liquid goes below it's Vapor Pressure and recovers back above the Vapor Pressure.
A valve that flies
Butterfly
Linear component of a globe valve
Stem/Plug
Allowable DBA per OSHA
85
plus define OSHA
Define Fail Closed Valve/Actuator
ON loss of air or electricity the valve closes
Flashing
When a flowing liquid goes below it's Vapor Pressure and stays below the Vapor Pressure on recovery.
A gate valve that cuts
Knife Gate
Lives In A Box
Packing
Flow that has entrained solids
slurry
Define fail in place valve
On loss of power to actuator, the valve fails right where it is.
Vena Contracta
The flow at its highest velocity and lowest pressure.
The "Worldly Valve"
Globe Valve
Plug - Stem - Seat Ring =
Trim
Flow that is a combination of liquid and gas
Two Phase
3 main CV characteristics
Equal Percentage - Linear - Quick Opening
CV Definition
The number of gallons of water per minute that flow across an orifice with a 1 pound pressure drop.
US gallons at 60 F
The sharpest of all valves
Needle Valve
The Brains of the CV
Positioner
Is a liquid with high viscosity "thick or thin?"
Thick
Define Choked Flow
An increase in pressure drop no longer results in flow rate increase
CV Equation
Flow (Q) x's Square Root of S.G./Delta P
A valve that the MLB uses.
Ball Valve
The muscle of the CV
Actuator
Define Design P&T vs Op P&T
Operating = actual P&T valve sees day to day
Design = what the valve "could" see worst case
Define Rangeability
The ratio of max controlable flow to min controlable flow