Profile: EstelleMadri

Your personal background.
A repair person can come to your place and fix the problem in time relatively quite
less when compared to the time in comparing features and prices and finally shopping one from the market.
One cause is that if there is no relief valve between stages (or it
is stuck or clogged), when incompressible oil fills the pump chambers, the only place for it to go when the pump
is started is through the microscopic gaps between moving parts.
It is the water pressure against the underside of the discs which keeps them
in place. I still doubt they would reach spec'd pressure though I have seen another pump (Ulvac Sinku-Kiko G-50D) come in well under its more conservative
rated base pressure of 0.75 microns after a flushing and two oil changes.
I've measured less than 0.04 Torr for a 1399 (single-stage) with
new oil after flushing and under 2 microns for a 1402 (two-stage) with new
oil but without flushing. 7. Single-stage and two-stage Welch
pumps should not be run continuously with inlet pressures above 50 and 10 Torr, respectively.
8. If some of these pumps are idle for a long time, especially with the inlet left at vacuum when powered down, the first
couple rotations could then have tough spots resulting in a
stalled motor or smoking slip clutch (if present) the next time it is started.

Even for the CO2 laser with the smallest pump, the inlet pressure should be quite low.
The typical commercial flowing gas 50 W-class CO2 laser used a Welch 1399.) The 1402 (and 1380) are
really total overkill in terms of pumping speed but the 1402 tends
to turn up surplus quite frequently so a good deal
on one in decent condition shouldn't be passed up unless you don't have someone to help drag it home!
Anything larger than a 1402 is just plain silly for use with home-built lasers.
Where this situation is found to be the case with your pump,
rotating the pulley through a few cycles first
by hand is a good idea to reduce starting stress on the motor and/or slip clutch.
Given the choice between a single-stage or two-stage pump
with otherwise similar specs, get the two-stage model as it should be able to
deal with all of the home-built lasers without requiring a diffusion or turbo pump if it is in good condition. But, don't let the pump run for hours with
nothing connected just because you like the way it gurgles.
Cycle on the dishwasher for a test run while watching for leaks.
Even within each pump chamber, there may be a portion of the cycle where the trapped
space is decreasing in volume with no outlet
for incompressible oil.

Various older belt-driven Welch models appear from
time-to-time on eBay and elsewhere but listed information for them - including what I have above for pumping speed and even the number of stages - may not be
reliable. Notes 1. The "Pumping Speed" values used here are the manufacturer's
free air displacement ratings. The difference
in pumping speed may correlate with the version change. But if you prefer to refurbish
anything you currently get--rather than selecting pricey replacing--you might get the house changes you may need without
worrying about absurd price tags! I have listed the big ones here so you will know not
to get too excited about those models should you find them in a catalog or auction unless,
of course, you just want to have the biggest pump on your block!
4. Sometimes, especially with older pumps, there is no model number listed
on the nameplate, just "Welch Duo Seal Vacuum Pump" (or something similar).
There are water heaters and washing machines from Mexico,
T.V.s, and refrigerators from South Korea, vacuums, and Germany’s grills.
And, those 50 year old pumps are still serviceable, requiring at
most a cleaning and relatively inexpensive rebuild
kit to meet original factory specifications.

From trips on my mountain bike around an area within a few miles of my home, I was
aware of some places that people sometimes illegally dumped old
appliances. There are certain appliances such as KitchenAid Washers that are
frequently used in most homes. If one of these machines gives you, we understand the correct
way effortless they really are. Washing Machine Repair - Common problems, leaking washers and washing machines that won't start.
He checked my washing machine and made sure it was safe to use.
Most of their line is approved and rated for even outdoor use.

Even some of the info on Welch's Web site is not accurate
including a few mislabled photos and part diagrams. Exploded parts diagram and parts list available on Welch's Web site.

More detailed specifications for these as well as Welch's direct drive pumps may be found on the Welch
Vacuum Web site.

Here is my webpage :: "
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