1.2 The Inlet Piping Should Include
the Following:
1. The tank excess flow valve (EFV) should have a flow
rate of 1-1/2 to 2 times the capacity of he pump. Do
not use an EFV without knowing its flow capacity.
2. The tank shut-off valve must be a free-flow type and
not a standard globe valve.
3. A strainer of the “Y” type, with 30 to 40 mesh screen,
must be on the inlet line of the pump. (Mesh size
indicates the number of openings per lineal inch).
4. Use a flexible connection in the pump inlet and outlet
piping to compensate for piping strains.
5. Use an eccentric swage at the pump inlet nozzle to
change the line size (flat side up).
6. Make the inlet line level or slope it downward to the pump.
7. The minium inlet piping sizes shown in figure 1.2 must
be observed.
1.3 The Outlet Piping Should
Include the Following:
1. A pressure gauge should be installed in the pump
outlet or near it. A pressure gauge is necessary to
determine the efficiency of your pumping system.
2. A hydrostatic relief valve is required by most state
laws and for your own safety.
3. If the outlet piping exceeds 50 feet (15.2 m) in length a
check valve should be installed near the pump outlet.
4. The minimum outlet piping sizes shown in figure 1.2
should be observed.
1.4 The Bypass System Must
Include the Following:
1. A pump bypass system must be installed. If the pump
discharge is shut off before the driver is stopped,
dangerously high pressures can develop, unless a
bypass valve is installed to permit the pump to discharge
back to the supply tank, at a predetermined pressure.
2. The pump may have an internal relief valve, but it is
intended as a safety relief valve device and not an
operational bypass.
3. Always install an external bypass relief valve (such
as the Corken B177) in the pump discharge line.
The bypass valve may discharge into the tank at any
convenient opening, either liquid or vapor; however, it
should not connect into the pump inlet piping system.
Model Maximum Differential Pressure
521, 1021, F1021 125 psi (8.8 kg/cm
2
)
F1521 100 psi (7.0 kg/cm
2
)
1.5 A Vapor Equalizing System
Should be Included:
To obtain maximum performance from the Coro-Vane
®
pump, a vapor equalizing system should be installed.
This system is simply a pipe connecting the vapor
sections of the tank being unloaded and the tank being
filled. This equalizing line allows vapor to move freely
between the two tanks (in either direction) and assures
that both tanks remain at the same pressure.
As liquid is withdrawn from a tank, it must be replaced
by an equal amount of vapor or the pressure in the tank
will drop. If an equalizing line is not present, this vapor
is formed by “boiling” of the liquid and a reduction of
the tank’s pressure. Meanwhile, the tank being filled
experiences a pressure increase as the rising fluid levels
compresses the vapor space above it. A vapor equalizing
line will eliminate both of these problems and will reduce
pumping time, differential pressure, noise and wear
on the entire system. Slow transfer rates will minimize
these effects and reduce the need for a vapor equalizing
line. However, today’s high transfer rates require the
installation of a vapor equalization line.
Another way to consider this principle is to remember
how it takes two holes in an oil can for oil to be poured
smoothly from the can; one for the oil to exit and the
other for the air to enter. The piping and hose sizes
shown in figure 1.2 are minimum requirements.
1.6 Driver Installation
Model Maximum Speed
521, 1021, F1021 950 RPM
F1521 860 RPM
The wiring of your electric motor is extremely important
and must be done by a competent electrical contractor.
The following wire sizing chart indicates the minimum
standards for wire sizes.
6
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