Testing The Swivel Seals For Internal Leakage - NPK M20S Instruction Manual

SWIVEL MANIFOLD MAINTENANCE

TESTING THE SWIVEL SEALS FOR INTERNAL LEAKAGE

If internal leakage is suspected, before disassembling the swivel assembly, the relief
valve (c17/c18) pressure settings should be checked. Internal leakage will most likely
prevent the unit from reaching its relief settings in both the open and close functions.
The relief valve cartridges are located in blocks (bs24) mounted to the swivel manifold
assembly near the four hose connections (see Fig. 2). Access to these is through the
upper side access plates of the processor main frame (see Fig. 3). The relief valve
setting adjustment screws (va1) are located beneath plastic caps. NOTE: Before
attempting to adjust the relief setting, check that the relief valve cartridges have not
loosened in their blocks.
Fig. 2 Fig. 3
Test Procedure
Install 0 to 5,000 psi (0 to 350 bar) gauges in the NPK stop valves (located on the stick
of the carrier) or in gauge ports in the open and close circuits located near the end of
the stick (for carriers without an NPK hydraulic kit). Close the jaw and keep the function
activated, then read the pressure indicated on the gauge. Compare the pressure
reached with the specifications for your model processor. Repeat the check while
opening the jaws and read the pressure indicated. If the proper relief pressure cannot
be reached and the booster slows or stops, disassemble the swivel to check for failed
seals. NOTE: If the relief pressure cannot be reached with the jaw closed and the
intensifier booster is clicking rapidly, the relief valves are not the problem and the
intensifier booster should be checked.
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