Variable speed motor
- Used to control flow in a system by varying the frequency of
the motor. Recommended for circulating systems and any other
system where the main head is friction losses in the piping
- A German standard for mechanical seals.
- Any pressure less than atmospheric. Can present a problem for
the elastomer in many seal applications.
Vane passing syndrome
- A type of cavitation caused by the impeller/ cutwater
clearance being too small.
- Below this pressure, the liquid at this temperature will
- The fluid passes from a liquid to a gaseous state. If this
happens at the seal faces the seal faces will be blown open.
- A measurement of the speed of the liquid in the system.
Measured in feet or meters per second. The pump is a constant
- Part of the total head calculation. Derived from the formula h
- To remove air or gas from the system. It is important to vent
the stuffing box in vertical pumps to prevent the seal faces from
- Important in metal bellows seal designs. The elastomer acts as
a vibration damper in the other seals. The vibration can chip
carbon faces, destroy anti-rotation drive lugs, and open the
lapped seal faces.
- Resistance to pouring. Higher viscosities can restrict seal
movement. Centrifugal pumps can handle a maximum viscosity similar
to 30 weight oil at room temperature. Above this viscosity a
positive displacement pump should be used.
- An E.I. Dupont Dow manufactured elastomer widely used in the
sealing industry. The generic name is fluorocarbon. Many of these
compounds are attacked by water and steam.
- Derives is name from a spiral shaped casing surrounding the
pump impeller. It converts velocity energy to pressure
- A type of pump used for excessive solids. The impeller is
recessed into the volute. A very low efficiency design, but
practical in many applications.
- Creating a "whirlpool affect" that can draw air into the
suction of the pump.
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