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Dixon Sanitary 2014
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Technical
PSIG
Pounds per square inch gauge
PTFE
Tetrafluoroethylene, is a high performance thermo plastic polymer that has excellent dielectric strength, chemical and
temperature resistance.
Passivation
removal of exogenous iron or iron from the surface of stainless steels and higher alloys by means of a chemical
dissolution, most typically by a treatment with an acid solution that will remove the surface contamination and enhance the
formation of the passive layer.
Pipe
pipe size is determined by diameter and either schedule, series or SDR. For bioprocessing equipment, pipe does not
include tube.
Pipe Friction Loss
The positive head (fluid pressure) loss due to friction resistance between the pipe walls and the
moving liquid.
Pit
a small surface void resulting from a localized loss of base material.
Pneumatic Actuator
An air operated mechanical device used to open and close or modulate a valve. The actuator,
which is mounted to the valve by a bracket and coupled to the stem, is designed to convert air pressure into mechanical force
sufficient to operate the valve.
Polish
To make smooth and shiny by rubbing. Fittings may be machine polished to 180 grit finish.
Polypropylene
A lightweight synthetic plastic.
Positive Displacement Pump
A pump that causes a fluid to move by trapping a fixed amount of it then forcing
(
displacing) that trapped volume into the discharge pipe.
Pressure
The force per unit area applied on a surface in a direction perpendicular to that surface.
Pressure Head
Must be considered when a pumping system either begins or terminates in a tank which is under some
pressure other than atmospheric. The pressure in such a tank must first be converted to feet of liquid. A vacuum in the suction
tank or a positive pressure in the discharge tank must be added to the system head, whereas a positive pressure in the suction
tank or vacuum in the discharge tank would be subtracted. The following is a handy formula for converting inches of mercury
vacuum into feet of liquid.
Vacuum, in. of Hg X 1.13
Vacuum, ft of liquid = Sp. Gr.
The above forms of head, namely static, friction, velocity, and pressure, are combined to make up the total system head at any
particular flow rate.
Pressure Rating
pressure at which a system is designed to operate, allowing for applicable safety factors.
Prime.
A charge of liquid required beginning the pumping action of centrifugal pumps when the liquid source is lower than the
pump.
Profilometer
an instrument for the measurement of the degree of surface roughness.
Glossary of Terms
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