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16
PI Operation Manual
2. Remove the covers of the pump flanges.
3. Check whether the seals are correctly mounted.
4. Install a check valve and a gate valve in the discharge pipe. When the pump is stopped, the
check valve will protect the pump against excessive back-flow pressure and will prevent the pump
from running backward.
The check valve should be installed between the gate valve and discharge flange
in order to permit its inspection.
5. A spool piece should be installed in suction line so that the suction strainer may be installed
and removed with a pressure gauge between the strainer and pump.
6. The suction strainer should be installed between 5 to 20 pipe diameters upstream from the
suction flange.
7. Cone type strainers (otherwise known as “witches – hat” strainers) should be mounted as
recommended by the Hydraulic Institute, with the cone pointing upstream away from the pump,
into the oncoming flow. As the strainer gradually gathers particles from the liquid and blocks up,
this direction will result in the lowest turbulence impact onto the liquid flow entering the pump.
Figure 4.1. Correct mounting of a cone type strainer.
