2.
Stuffing box pressure may be below atmospheric pressure due to pump running with suction lift,
or when suction source is under vacuum. Under these conditions, the packing will not be cooled
Sealing liquid
Sealing liquid may be supplied by recirculation of pumpage through a line from the casing to the stuffing
box. If pumpage is abrasive, an outside source of clean compatible liquid must be used at a pressure of
30 to 50 PSI above suction pressure.
Grease lubricator
The grease lubricator is supplied when the use of a recirculating pumpage or outside sealing liquid is not
desired. The grease should be insoluble in the pumpage.
3.1.4 Connection of cooling water piping
Quench gland
Most pumps which contain stuffing box packing have quench glands. Quenching prevents heat transfer
along the pump shaft to bearings. Quenching is also most important for smothering vapors and fumes
given off at the stuffing box. This is particularly true on applications such as hot water.
The quenching liquid 9Usually water) must be from an outside source. It should be piped, with flexible
pipe, into the tapped opening on top of the stuffing box gland. A shut-off valve should be installed.
Bearings
Bearing cooling is available on some units. When it is available, cooling water must be connected to the
jacket when pumping hot liquids. See the temperature limits listed under Construction Details. in Sect
VIII-D. Valves should be installed in the coolant supply lines to regulate the flow.
Stuffing boxes
Some units are equipped with cooling jackets around the stuffing box as standard. It is optional on vari-
ous other models. Coolant lines are connected in the same manner as the bearing cooling lines.
Casing pedestals
O, water cooled pedestals are available. Connection of coolant lines is made in the same manner as
above some models
Mechanical seals
Seal materials (carbon, ceramic, PTFE, etc.) are suitable for use at temperatures to 500ºF (212º to 250ºF
if seal has rubber parts). However, for satisfactory operation, there must be a liquid film between the seal
faces to lubricate them. If the liquid flashes to vapor, the faces will run dry and be damaged. To prevent
this, the liquid must be cool. In general, this requires that the liquid be cooled so that the vapor pressure
is well below the stuffing box pressure. Doubtful cases should be referred to Goulds for a recommenda-
tion. Refer to seal manufacturer's drawing for location of taps. Some methods which may be used to cool
the seal are:
1.
Dead ended seal chamber
No liquid is circulated through the stuffing box. The isolated or dead ended liquid around the seal
is cooled by circulating water in the stuffing box jacket, if any.
2.
Cool liquid flushing - external source
A clean, cool compatible liquid is injected from an outside source directly into the seal chamber.
The flushing liquid must be at a pressure 20 to 40 PSI greater than the pressure in the stuffing
box. One-half to two GPM should be injected. A control valve and rotometer placed in the inlet
3.1 Pump Bearings
Model 3415 Installation, Operation, and Maintenance Manual
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