Breaking Vacuum; Cross Reference Of Vacuum Measurements - JB INDUSTRIES ELIMINATOR DV-3E Manual De Instrucciones

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 (Figure 17)
Figure 17

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
MEASURING VACUUM IN
MICRONS OR INCHES?
vacuum pumps, simply close the isolation
JB INDUSTRIES • ELIMINATOR OPERATING MANUAL • 800.323.0811 • SALES@JBIND.COM • JBIND.COM
CROSS REFERENCE OF
VACUUM MEASUREMENTS
Boiling temperature of water at converted pressures (Figure 18)
INCHES OF HG
TEMP. F° MICRONS
212 759,968
205 535,000
194 525,526
176 355,092
158 233,680
140 149,352
122 92,456
104 55,118
86 31,750
80 25,400
76 22,860
72 20,320
69 17,780
64 15,240
59 12,700
53 10,160
45 7,620
32 4,572
21 2,540
6 1,270
-24 254
-35 127
-60 25.4
-70 12.7
-90 2.5
--- 0.00
Figure 18
PRESSURE POUNDS
VACUUM SQ. IN.
0.00 14.696
4.92 12.279
9.23 10.162
15.94 6.866
20.72 4.519
24.04 2.888
26.28 1.788
27.75 1.066
28.67 0.614
28.92 0.491
29.02 0.442
29.12 0.393
29.22 0.344
29.32 0.295
29.42 0.246
29.52 0.196
29.62 0.147
29.74 0.088
29.82 0.049
29.87 0.0245
29.91 0.0049
29.915 0.00245
29.919 0.00049
29.9195 0.00024
29.9199 0.00005
29.92 0.00000
7