TM 5-810-15
gallons per hour (gph), discharge head in psig and
Coolers for individual samples are either double-
piston strokes per minute. The chemical feed
tube helical coils with cooling water counterflow
pumps will be positive displacement metering type.
cooling or submerged helical coils properly baffled
The pumps will have hydraulically balanced
to effect counterflow cooling. If a coil type of
diaphragms, mechanically actuated air venting; all
exchanger or a coil and condenser type of ex-
rotating parts to run in an oil bath with roller
changer are used, they will meet the intention of
bearings; double ball check valves with Teflon 0-
ASTM D 1192. If a multicircuit heat exchanger is
ring seats on both suction and discharge. The
used, it will meet the requirements of Section VIII,
pumps will have micrometer capacity adjustment
ASME Boiler and Pressure Vessel Code.
from 0--100 percent while the pump is running and
to have metering accuracy within plus or minus 1
7-21.
Sump pumps.
percent.
a. Application. Sump pumps are required in
c. Chemical feed unit. Chemical feed tanks for
several applications at a boiler plant. Sump pumps
the mentioned chemicals will be 16 gage type 304
primarily are used for storm water removal but also
stainless steel with agitator, gage glass and low
are used for ash hopper water overflow or any
level alarm system. Piping will be stainless steel and
condition requiring removal of water from a sump.
valves will have Teflon seats. The chemical feed
b. Design. The pump will be sized for one and
system will include a back pressure valve to insure
one-half times the maximum amount of expected
accurate and consistent metering at all flows and
drain rate. Two 100 percent capacity pumps will be
will include a safety valve.
used to supply full backup if overflow is dangerous.
The suction line between the suction vessel and the
7-20.
Laboratory.
pump must be properly designed to prevent air
a. General. A laboratory is needed in every boiler
pockets and cavitation. Sufficient NPSH must be
plate to assist in analyzing chemical treatment and
available at the pump suction flange.
c. Construction. The pumps will be motor
in early detection of problems. Samples of water
and steam are taken from various systems and parts
driven, vertical shaft configuration with bottom
of systems to evaluate the system*s condition.
suction and open impeller. The pump will include a
b. Sample coolers. Sample coolers are required
flanged column, discharge pipe flanged over
to condense steam and cool water to be handled.
soleplate, bearing lubrication piping and connec-
Sample coolers are heat exchangers that will be
tions on the soleplate to support the pump and
sized to maintain the temperature at 77 degrees F.
motor.
7-16
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