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Forcing bolts shall be provided for breaking joints |
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| MIL-P-17639F(SH)
3.3.3.2 Casings of close-coupled and rigid-coupled pumps shall be designed
to permit ready replacement of wearing parts.
3.3.3.3 Casing thickness shall include an allowance for corrosion and
the possibility of core shift. The minimum casing thickness shall be 1/2 inch
excluding class C-1 pumps with a rated total head of 115 feet or less. For
submarine sea water pumps, areas subject to fluid velocity in excess of 15 feet
per second at rated flow shall be readily renewable or shall be protected by
replaceable erosion shields.
3.3.3.4 Casings shall be sufficiently rugged to withstand without fracture
or appreciable distortion the strains to which they may be subjected. The
nozzle loadings to which the pump will be subjected will be calculated by the
shipbuilder and forwarded to the pump contractor by the contracting activity
(see 6.2.1). Under the combined effect of the nozzle loads and design pressure,
no parts of the casing or other pump parts shall exceed yield strength and no
rotating clearances shall make contact.
3.3.3.5 Clearance shall be provided around bolt heads and nuts to permit
the use of ordinary tools. Ordinary tools are tools which are listed in the
Federal Supply Catalog (copies of this catalog may be consulted in the office
of the DCASMA).
3.3.3.6 Fitted bolts or dowel pins shall be provided to insure main-
tenance of alinement in assembly. Dowel pins shall be corrosion-resistant,
shall have a threaded end and nut design, and shall be secured against coming
adrift under shock loading.
3.3.3.7 Forcing bolts shall be provided for breaking joints.
3.3.3.8 Casings of horizontal and vertical pumps other than submarine
sea water pumps shall be fitted with drain and vent connections. Drain connec-
tions shall be in accordance with MS16142 and MS18229 and shall permit complete
drainage of the pump without disassembly of the pump. For vertical, bottom
suction pumps, the pump suction may serve as the drain. Threaded drain connec-
tions are prohibited in the pressure boundary of submarine seawater pumps.
3.3.3.9 Gasket compression and tolerances shall not affect bearing,
bushing, and wearing ring fits to an extent that will adversely affect relia-
bility and performance.
3.3.3.10 For all pumps, the casings shall be fitted with removable casing
wearing rings. The casing wearing rings shall be located and shaped in such a
manner that leakage through wearing ring clearances shall not be allowed to
impinge directly on the casing.
3.3.3. 10.1 Spare casing wearing rings (see table 11) shall be machined
undersize by at least 0.050 inch on the diameter in order to permit finish
machining during overhaul installation to mate with machined-down used impellers.
3.3.3.11 Pump casing joints shall be made up using compressed asbestos
sheet gaskets, O-rings may be used to seal casing joints in the sea water pumps
for submarines. O-rings and gaskets are prohibited from being in contact with
highly-alloyed corrosion-resistant steel parts.
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