DH Instruments MPC1-1000, Руководство пользователя

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MPC1-1000 and MPC1-3000 User’s Manual
5.2.4 PRESSURE DECREASE LEAK (BELOW ATMOSPHERE)
Only three conditions within the MPC1 can cause this type of leak:
1. A damaged or improperly closed test outlet valve when a vacuum source is connected
and the outlet selection valve is in the vacuum position.
2. A leaking VV piston O-ring.
3. A leaking or improperly closed equalization valve.
1. is the most probable cause. Check if the valve is properly closed; use caution not to
overtorque the valve. If an upward leak is still present, position the outlet selection valve
to OFF. If the leak stops, replace or repair the test outlet valve.
2. and 3. can only cause a leak of this type if the pressure in the front chamber of the VV is
below that in the test circuit. Reduce the pressure in the front chamber by closing the
equalization valve (push in) and rotate the VV knob clockwise.
The pressure in the test circuit will increase. Wait for pressure to stabilize. If pressure
begins to drop, check to see if the equalization valve is properly closed. If pressure continues
to drop, open equalization valve. Wait for pressure to stabilize. If pressure leak stops,
have VV serviced.
5.3 TEST PRESSURE WILL NOT CHANGE
There are three components involved in changing the pressure:
•
Test Inlet Valve (1)
•
Variable Volume (2)
•
Test Outlet Valve (4) (in conjunction with the Outlet Selection Valve (6))
The MPC1 uses very small inside diameter control tubes. The purpose of the filters is to protect these
tubes from contamination. Do NOT operate the MPC1 without an active filter element of less than a
0.5 micron rating.
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