Just Better Keeping the life of your pump - Manual (Page 3)

Cleaning and Testing Your Vacuum Pump Continued
Now, fi ll the pump to the proper oil
level and allow the pump to run with
the isolation valve closed for 3 or 4
minutes to warm up the oil. Check all
o-ring caps for dirt and proper seal.
Connect a micron gauge (JB recom-
mends the JB DV-22N pictured to the
right) directly to either the 1/4” port or
the 3/8” port on the intake tee (Figure
9). Do not use a charging line. Open
the isolation valve.
Using a charging line, especially a
new line, will give you a higher mi-
cron reading because you are reading
the environment inside the hose (see
Figure 10).
Figures 9 and 10 are the same, but
fi gure 9 is a direct connection hook-up
Figure 9
Figure 10
and fi gure 10 is a connection through a new charging line. Both hook-ups are
allowed to run the same length of time, but #9 is at 20 microns while #10 is at
297. If left on, the charging line hook-up will come down in its micron reading,
but it will take a much greater period of time. If the hose is cleaned out with al-
cohol and vacuumed for a long period of time, the micron reading will go lower.
This test can be performed on a pump with dirty, used oil and then with the
pump cleaned and fl ushed, as described earlier, to see the difference that just
maintaining the cleanliness inside your pump affects the performance for deep
vacuum.
OPEN
POSITION
PAUSE
POSITION
CLOSED
POSITION
Isolation Valve
It is a quarter turn between on and off.
There is no additional valve needed
to isolate the system. When check-
ing for pressure rise, slowly turn the
handle counter-clockwise. The pause
position is at 45 degrees and the valve
is completely closed at 90 degrees
(Figure 11).
Figure 11
DIRECTION OF PERMEATION
THROUGH HOSE WALL
CHARGING SYSTEM
Gas under pressure in the hose
will permeate to the lower
pressure of the atmosphere.
EVACUATION (Hose under Vacuum)
The atmosphere which has a higher
pressure permeates to the lower
pressure in the hose.
Using Charging and Testing
Hoses for Evacuation
You probably think there is a leak. How-
ever, an evacuation/ dehydration hook-up
requires a leak-proof design in all of the
components. Only soft copper tubing,
pure rubber hoses, or fl exible metal hoses
are absolutely vacuum tight. Charging
hoses are designed for positive pressure.
Even with the advanced technology of to-
day’s hoses, permeation through the hose
compound still exists (Figure 12).
If you have blanked-off your pump
to check pressure rise and your hoses
and connections are not leak-free, the
atmosphere will permeate to the lower
pressure in the hoses. Your reading will
slowly rise and you will spend time look-
ing for system leaks.
Information on Testing the Vacuum Pump’s Isolation Valve
The easiest way to test the isolation valve
for leakage is to turn the pump on with
the isolation valve in the closed position.
Connect a charging line to the center port
of the manifold (Figure 13), and have the
high side capped off and CLOSED and
the low side capped off and OPENED.
Then, connect the charging line to the
intake of the pump and wait. If, within
5 to 10 minutes, you do not see the low
(compound) gauge going into inches of
vacuum, there is no leak in the isolation
valve.
What does happen when a micron gauge
Figure 12
Figure 13
is connected directly to the intake of a vacuum pump with an isolation valve/ It
is all related to the connections to, and including, the intake, the volume of what
is being vacuumed, the depth of vacuum, and the length of time that the volume
is in the deep vacuum.
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