Parts Identification - (Cont.)

Distribution of the high pressure on the back side of the pressure plates is shown above.  This area is of sufficient size to keep the pressure plate tight against the ends of the gears.

A pump can also be identified as a reversible or uni-directional unit by the following items:  Flange, Pressure Plate and Isolation Plates.

Only two isolation plates (above) are needed per unit in uni-directional gear pumps.  The plate with the rounded edges along the outer radius goes in the bottom of the housing with the round edge down.  The plate with the square edges along the radius goes on top, next to the flange.

The pictures at right show flanges for uni-directional and reversible pumps.  The uni-directional flange is on the far right.  Note the two threaded holes near the bearing bores.  A pipe plug (or rotation plug) is installed in the hole which is on the high pressure side of the pump.  The location of the plug is therefore determined by the direction of rotation for which the pump is assembled.   The flange on the left side has a check valve on each side and will operate automatically for either rotation of the pump.

Pressure plates are shown at right.  The uni-directional pump pressure plate (far right) has only one set of traps.  The reversible pump pressure plate (left side of picture at right) has two sets of traps and a flat end on each end of the plate .

When changing operating directions of uni-directional pumps see your Service Manual for details.