ITT GOULDS PUMPS 3316, Инструкции по установке, эксплуатации и обслуживанию

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c) Bypassing Around Discharge Check Valve See Figure 15: on page 24
Figure 15:
This method can be used only when there is liquid under some pressure in the discharge line. The
original prime must be effected from some outside source. After subsequent idle periods, open air
vent valves and open valve in bypass line around discharge check and gate valves until liquid flows
from air vent openings. Close air vent valves and bypass valve, start pump and open discharge
gate valve.
The valve in bypass can be left open, in
which event, during idle periods, loss through foot valve is constantly replenished from discharge
line. This system is used for automatic operation where idle periods are of short duration and there
is no danger of exhausting all liquid from discharge line, due to a leaky foot valve. If the valve in the
bypass is left open, as described above, the foot valve must be capable of withstanding static head
pressure of the system.
3. Priming by Ejector, See Figure 16: on page 25 :
On suction lift installations, an ejector, operated by steam, compressed air, or water under pressure,
and connected to tapped opening in second stage vent valve (remove vent tubing and fitting from
valve) can be used to remove air from casing and suction line, thus priming the pump.
Close discharge gate valve, open valve "E" in steam, air or water pressure supply· line. Open valve
"S" in suction pipe of ejector connected to pump casing. Air will be evacuated and liquid will be
drawn up into suction pipe and pump casing. When all air is evacuated, start pump, close valve "S"
and valve "E", and open discharge gate valve.
4.1 Priming
24 3316 Installation, Operation and Maintenance Instructions