Negative pressure; a region in a pump or a pipe that is below atmospheric pressure.
VACUUM WALL FITTING
The fitting in the wall of the pool just below the water level to which is attached the hose for the underwater suction cleaner.
VELOCITY
The measurement of the motion of liquids, expressed in feet per second.
VENTURI
A cylindrical tube that gradually increases in size. When used in conjunction with a nozzle, it converts the velocity of the liquid being pumped to pressure.
VENTURI TUBE
A tube, which has a constricted throat, which causes differences in pressure and can be used to operate feeding devices, instruments and to measure flow.
VERTICAL WALL
Shall refer to the wall up to a positive 11° angle towards the pool’s interior from plumb.
VIRUS
The smallest infectious microorganism, made of RNA or DNA, in a protein shell, which grow only in other, living cells. They are 0.004 to 0.1 microns in size and about 100 times smaller than bacteria.
VISCOSITY
The resistance of a fluid to flowing freely, caused by friction from its molecules.
VOC
Volatile Organic Compound-a category of water contaminates.
VOLTAGE LOSS
The amount of electricity used to force current(amps) to where it needs to go. This can be caused various ways such as too small of wire, too long of a run, etc.
VOLTS
An electrical measurement of motor performance where voltage(volts) = current(amps) x resistance(ohms). Volts measures the pressure of electricity.
VOLUME
The contents of a space that is formed by lines that can be measured in three directions (length x width x height). In pipe the formula is Area x Pipe Length.
VOLUTE CASE
A pump housing that is spiral or scroll shaped where the suction and discharge pipes screw into the unit.