Goulds Pumps 3410 - IOM - Manual (Page 33)

2. Priming By Separate Hand, or Manually
Controlled, Priming Pump (Fig. 29).
• Close discharge gate valve (do not remove vent plug)
and open valve in line to priming pump. Exhaust air
from pump and suction piping until water flows from
priming pump. With priming pump running, close
valve in priming line, start pump, and open discharge
gate valve.
• An alternate method is to reverse connections on
priming pump and extending priming pump suction to
source of liquid supply. The pump may be primed by
pumping liquid into casing until liquid comes out of
open air vent plug removed.
• In either of these methods (1) and (2), pump will
remain primed, provided foot valve is tight. Any
failure, however, of foot valve when pump is standing
idle will permit pump to lose its time. During long
idle periods, pump can also lose its prime through
leakage from stuffing boxes.
3. Bypassing Around Discharge Check Valve
(Fig. 30).
This method can be used only when there is liquid
under some pressure in discharge line. The original
prime must be affected from some outside source.
After subsequent idle periods, open air vents and open
valve in bypass line around discharge check and gate
valves until liquid flows air vent openings. Close air
vents 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. Foot valve must be capable of
withstanding static head pressure of system.
Priming by Ejection
1. On suction lift installation, an ejector, operated by
steam, compressed air, or water under pressure, and
connected to tapped opening in top of casing can be
used to remove air from casing and suction line, thus
priming pump. See Fig. 31.
2. 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.
3410 IOM 1/2010
31
Fig. 28
Fig. 29
Fig. 30
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