ITT Goulds Pump 3355, Инструкция по установке, эксплуатации и обслуживанию

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Check Explanation/comment Checked
Check that the suction piping slopes up-
wards from the liquid source to the pump
inlet. —
If the pump is not self-priming, check that a
device for priming the pump is installed. Use a foot valve with a diameter that is at least equiva-
lent to the diameter of the suction piping.
Liquid source above the pump
Check Explanation/comment Checked
Check that an isolation valve is installed in
the suction piping at a distance of at least
two times the pipe diameter from the suc-
tion inlet. This permits you to close the line during pump inspec-
tion and maintenance.
Do not use the isolation valve to throttle the pump.
Throttling can cause these problems:
• Loss of priming
• Excessive temperatures
• Damage to the pump
• Voiding the warranty
Make sure that the suction piping is free
from air pockets. This helps to prevent the occurrence of air and cavita-
tion in the pump inlet.
Check that the piping is level or slopes
downward from the liquid source. —
Make sure that no part of the suction pip-
ing extends below the suction flange of the
pump. —
Make sure that the suction piping is ade-
quately submerged below the surface of
the liquid source. This prevents air from entering the pump through a
suction vortex.
4.5.4 Discharge piping checklist
Checklist
Check Explanation/comment Checked
Check that an isolation valve is installed in
the discharge line. For specific gravity less
than 0.60, minimize distance from pump
discharge. The isolation valve is required for:
• Priming
• Regulation of flow
• Inspection and maintenance of the pump
• Reduce risk of pumpage vaporization and vapor
locking at low flow rates for low specific gravity liq-
uids.
Check that a check valve is installed in the
discharge line, between the isolation valve
and the pump discharge outlet. The location between the isolation valve and the pump
allows inspection of the check valve.
The check valve prevents damage to the pump and seal
due to the back flow through the pump, when the drive
unit is shut off. It is also used to restrain the liquid flow.
If increasers are used, check that they are
installed between the pump and the check
valve.
If quick-closing valves are installed in the
system, check that cushioning devices are
used.
This protects the pump from surges and water hammer.
4.5 Piping checklists
34 Model 3355 Installation, Operation, and Maintenance Manual