Goulds Pumps CV 3171 - IOM - Manual (Page 19)

CV 3171 IOM 05/11 19
PIPING
General
Guidelines for piping are given in the “Hydraulic
Institute Standards” available from: Hydraulic
Institute, 9 Sylvan Way, Parsippany, NJ, 07054-
3802 and must be reviewed prior to pump
installation.
1. All piping must be supported independently of,
and line up naturally with, the pump discharge
pipe.
2. Piping runs should be as short as possible to
minimize friction losses.
3. DO NOT connect piping to pump until the
anchor bolts have been tightened.
4. Carefully clean all pipe parts, valves and fittings,
prior to assembly.
5. Isolation and check valves should be installed in
the discharge line. Locate the check valve
between the isolation valve and the pump in
order to permit inspection of the check valve.
The isolation valve is required for inspection of
the pump and flow regulation. The check valve
prevents pump damage due to reverse flow
through the pump when the driver is turned off.
6. Increasers, if used, should be installed between
the pump and check valve to minimize friction
losses through the check valve.
7. Cushioning devices should be used to protect
the pump from surges and water hammer if
quick closing valves are installed in the system.
Suction Piping - For Optional Dry Pit,
Outside Tank Mount, and Tailpipe
Applications ONLY
WARNING
NPSH
A
must always exceed
NPSH
R
as shown on Goulds
performance curve received with
order. Reference Hydraulic Institute standard for
NPSH and pipe friction values needed to
evaluate suction piping.
1. The general requirement for the pump is to
install an elbow at the pump. Long radius elbows
are recommended. If an elbow can be
eliminated or moved further from the suction, it
would be recommended to do this.
2. Suction piping should never be of a smaller
diameter than the pump suction.
3. Pump should never be throttled on the suction
side.
4. Separate suction lines are recommended when
more than one pump is operating from the same
source of supply.
5. Suction pipe must be free of air pockets.
6. Suction piping must slope upwards to the pump.
7. All joints must be airtight.
8. A means of priming the pump must be provided.
For outside tank mount and dry pit, this is
usually accomplished by allowing the fluid level
inside the tank/pit to rise above the casing level.
In tailpipe applications, the casing must be
submerged prior to starting the pump.
9. For outside tank mount and dry pit applications,
an isolation valve should be installed in the
suction line at least two pipe diameters from the
suction to permit closing the line for pump
inspection and maintenance. Isolation valve
must be kept fully open during operation.
10. The entrance to the suction pipe must be kept
adequately submerged below the free liquid
surface to prevent vortices and air entrainment.
Outside Tank Mount Only
The outside tank mount option has a column
assembly that allows the fluid coming through the
lower bushings to flow up through the column and
back through the connection at the top of the column
back to the tank. The pipe at the top of the pump
column must be connected back to the source tank
to prevent fluid from entering the thrust bearing.
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