exposed to the fluid in the reservoir. The magnet shall be [combined in
the construction of the fill strainer] [mounted on a removable rod assembly
installed through the top of the reservoir] [or] [incorporated in the
bottom drain plug]. [The drain plug type installation shall incorporate an
automatic valve arranged to permit removal of the magnetic separator for
inspection without loss of fluid from the reservoir.] [The drain plug type
installation shall include provisions for automatic chip detection without
removal of the plug.]
2.1.7.3
Air Breather
The reservoir shall be provided with an air breather which removes dirt and
moisture from the incoming air. The incoming air shall first pass through
a desiccant bed to remove the moisture, and then pass through a filter to
eliminate the solid contaminants before entering the reservoir. Outgoing
air shall pass directly to the atmosphere through a check valve. The
breather shall also provide visual indication of the desiccant and filter
condition.
2.1.8
Pumps
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NOTE: The submerged pump option should be used only
where space is restricted so that the pump cannot be
mounted on the exterior of the reservoir with the
pump suction flooded.
If the designer elects to select the particular type
of pump to be used, the following factors should be
considered: displacement, pressure rating,
prime-mover speed, rated pump life, initial cost,
mountings available, serviceability, porting
connections, availability, compatibility, product
history, efficiencies, and size and weight. Fixed
displacement pumps are usually lower in cost, on a
component basis. However, the lower initial cost of
the pump must be weighed against the cost of the
control components needed to make the system work.
Variable displacement pumps, conversely, are
generally higher in cost, but less control equipment
may be needed to achieve the same result. The
reduced control costs may more than offset the
higher initial pump cost. As a general rule, gear
pumps are usually least costly, vane pumps
intermediate, and piston pumps most costly.
However, on the basis of cost per watt (horsepower),
there is no clear-cut rule. Each application must
be evaluated individually.
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The pump[s] for the hydraulic system shall be a[n] [submersible,] electric
motor-driven, [variable] [fixed] displacement, [gear] [vane] [piston] type
[with constant wattage horsepower control to regulate flow rate and
pressure] [rated to deliver a nominal [_____] L/s at [_____] kPa [_____]
gpm at [_____] psi] while operating with the specified oil in the specified
temperature range. Maximum rotating speed shall be 1800 rpm. Exposed
rotating parts shall be properly safety guarded. The pumps shall mount
[in] [on] the reservoir in a manner similar to that shown on the drawings
so that the pump suction is flooded. The pumps shall operate on [_____]
SECTION 15010A
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