Erratic Readings; Breaking Vacuum - JB INDUSTRIES PLATINUM DV-200N Manual De Instrucciones

Erratic Readings

There are three issues involved in the discussion of erratic readings One is the
understanding of the gauge' s displayed micron increments that was just discussed
The second involves the re-sampling period The third is the environment inside the
system being evacuated When JB digital vacuum gauges are turned on, the display
will show "JB" and the sensor will start to calculate the ambient temperature
Once the gauge has finished calculating the ambient temperature, it will display
"OOOOOO" indicating over-range if it is not introduced to a vacuum level of
100,000 microns or less
There is also instability inside the system being evacuated Liquids (moisture) are
being turned into gases and molecules are moving at different rates of collision with
other molecules at different areas of the system at different times between the high
and low sides The deeper the vacuum, the further apart these molecules get and
the less rubbing together This decrease in friction changes the temperature around
those molecules and the JB digital vacuum gauge is registering those changes
by way of temperature changes at the sensor's filament The environment inside a
system being evacuated has more instability at higher micron levels (9000 to 1000)
than at lower micron levels (700 to 50) This is evidenced when testing JB digital
vacuum gauges at the different ranges on a secured system When in the range
of 4000 microns, the gauge display will show 4000 microns, then jump to 4350,
then regress to 3875, then jump back to 4000 After being blanked-off at this level
for a period of time, the changing back and forth will level out to changing from
the incremental display of 4000 microns and the next incremental display up or
down of either 4125 or 3875 But, when in a deeper vacuum like 350 microns, the
changes in display on increments may be from 350 to 357 and back down to 350
or even 329 as the environment inside the system becomes more stable and the
time period of these changes will be less as most of the out gassing has been done
JB INDUSTRIES • PLATINUM OPERATING MANUAL • 800.323.0811 • SALES@JBIND.COM • JBIND.COM
8
MEASURING VACUUM IN
MICRONS OR INCHES?

Breaking Vacuum

Breaking vacuum prior to shut down is important on larger CFM pumps This
procedure relieves the stress on the flexible coupler on the next start up When a
pump is shut down without breaking vacuum, the oil in the cover is pulled back
into the cartridge and intake chamber of the pump trying to fill the vacuum there
Upon the next start up the pump has to clear the oil out of these areas and all the
stress is on the flexible part of the coupler, especially if the oil is cold You can see
this occurring by shutting down the pump and watching the sight glass The oil
will start to drop down and appears as if you are low on oil Then when you restart
the pump the oil level returns to normal
To break vacuum on the PLATINUM
®
valve with the pump still running and open the gas ballast valve all the way and
allow the pump to run 2-3 seconds with the gas ballast valve opened and then shut
pump off and close the valve
To break vacuum on the Eliminator vacuum pumps After blanking off at the
manifold or an external isolation valve, if used, crack open the unused intake port
on the pump and allow to run 2-3 seconds and shut pump off
vacuum pumps, simply close the isolation