5
C4- Connecting The Piping
C4.1- General
Never use the pump as an anchorage point or as a carrier for the piping.
The pipes should be supported very near the pump (Fig. 5). It must be checked that any weight, stress or
strains on the piping system should not be transmitted to the pump. Therefore after completing the piping
installation, the bolt and connection on the suction and discharge nozzles must be loosened to ensure that
there is not any stress on the piping system to the pump.
The nominal sizes of the pump suction and discharge nozzles are no guide to the corrects sizes of
the suction and discharge piping. The nominal bores of the pipes should be same as or greater than those
of the pump nozzles. Never use pipes or accessories which have smaller bore than the pump nozzles.
Particularly foot valves, strainers, filters and non return valves must be preferred with larger free transition
areas. In general the flow velocities should not exceed 2 m/s in the suction piping and 3 m/s in the discharge
piping. Higher flow velocities will result in higher pressure drops, which could cause cavitation conditions in
the suction piping and excessive friction losses in the discharge piping.
Pipe joints should be by means of flanges with flange gaskets of proper size and material. Flange gasket
must be centered between the flange bolts in a such way that there is no interference with the flow of the liquid.
Thermal expansions of the pipework and excessive vibrations should be accommodated by suitable means
so as not to impose any extra load on the pump.
Prevent impurities such as welding beads, scale, sand and tow might be left in pipes while production of
the piping system harms the pump. Seal the pump nozzles by means of blind gasket to stop impurities get in
the pump. After assembling the system all the piping parts must be disassembled, thoroughly cleaned, painted
and reassembled again. If a strainer is used on the suction side of the pump, it must be cleaned after several
days of operation.
ATTENTION
C4.2- Discharge piping (Fig. 6)
A control valve should be installed in the discharge pipe, as close to the pump as possible, to regulate the
required flow and head.
If the total head of the pump exceeds 10 meters or if discharge line is of appreciable length a non return
valve should be installed between the pump and isolating valve on the discharge line to protect the pump
against water hammer and reverse flow on shut down.
Isolation Valve
Vent Valve
Fig. 7.
C4.3- Auxiliary pipe connections and accessories
Depending on the application auxiliary pipe connections (for cooling, sealing
and flushing of seal, drainage etc. necessary for the pumping system) and/or
accessories to check the operating conditions (pressure gages, temperature
gages etc.) may be made up and laid.
Pressure and vacuum gauges must be properly anchored and connected at
the measuring points located on the pump flanges by means of or on the pipes
close to the flanges approximately 8 mm diameter tubing with pig tail configuration
to lessen pressure fluctuation. For safety purposes isolating and vent valves
should be fitted before the gages (Fig. 7).
Every pump is fitted with connections on the pump casing to drain the pump
and on the bearing bracket to evacuate the seal leakage from the stuffing box.
If required the pump drain and seal leakage can be piped to a suitable
reservoir. The pump draining piping must be fitted with an isolating valve and
both must be suitable for the maximum operating pressure of the pump.
Cooling, sealing and flushing of seal piping must be connected only to the
designated connections located on the pump.
