| Introduction The HyVac 30L and 55L vacuum pumps are basic oil sealed
rotary vane pumps known for years. These pumps are direct driven by a motor connected
directly to the vacuum pump using a coupling arrangement. The rotor is offset in and
rotates off-center in the stator. The rotor has 2 opposing slots cut in it where the vanes
sit and ride in and out maintaining constant contact with the stator using a spring to
maintain constant pressure as it rotates eccentrically in the stator. These pumps are
relatively simple in operation and are easy to repair. Because of the assembly and
manufacturing processes each pump is very consistent and the parts are not unique, are
interchangeable and often can even be refurbished. Parts are readily available and can be
purchased as needed based on the exploded view diagram in the manual.
Because they are direct drive and small in capacity they are light weight, quiet small
in size.
The 2 sizes are 30L (1 cubic foot per minute) and (55L 1.9 cubic feet per minute). The
30L is a single stage pump capable of 15 micron .015 Torr or greater than 29.9" Hg
Vacuum. The 55L is a two stage pump capable of .1 micron or .0001 Torr or greater than
29.9" Hg vacuum.
These pumps are extensively used in laboratories, and medical
equipment, vacuum ovens
and a myriad of other applications. They generate vacuum pressures in a very efficient
manner and are still a favorite for many applications.
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No Vacuum - The 30 and 55L pump
First off inspect the pump for correct oil level.
Second inspect the base of the hose nipple (inlet port) for a good sealant bead. I
can't tell you how many pumps we get with the hose nipple replaced with some other fitting
that is not properly sealed with a good vacuum sealant. For threaded sealing of HyVac
pumps we recommend HyVac PST sealant.
Assuming adequate oil and lubrication has been inspected and is present. Then remove
belt guard and turn pump motor on. If the pump pulley is rotating and still no vacuum is
present then turn the pump off. Your pump needs to see us or have an overhaul.
Generally assuming no vacuum often means no pump rotation, then your pump may have one
of the following problems.
First possibility, the coupling joining the pump and motor is not present or slipping.
The coupling rotation can be reviewed by shining a flashlight between the
pumped mounting
plate and the motor housing with the pump turned on. If this is not rotating then the
removal of the four screws in the back of the motor will disconnect pump and motor for
closer examination. If the coupling is secure on the pump shaft and the "spider"
that joins both couplings is present, the user can manually attempt to rotate the pump. If
this can not be accomplished the pump is locked and needs disassembly.
Second the vanes are stuck or locked
in the rotor and the pump needs disassembly and repair. Your pump rotates but vanes are not
working. Your vane springs and / or vane spring pins could be shot.
Third all valving on the top of the stators is missing.
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Low Vacuum -
First off inspect the pump for correct oil level and oil quality.
Second inspect the base of the hose nipple (inlet
port) for a good sealant bead. I can't tell you how many pumps we get with the hose nipple
replaced with some other fitting that is not properly sealed with a good vacuum sealant.
For threaded sealing of HyVac pumps we recommend HyVac PST sealant.
Assuming adequate oil quality and lubrication has been inspected and is present. Then
remove belt guard and turn pump motor on. If the pump pulley is rotating and still low
vacuum pressures (500 micron or so) are present then turn the pump off. Best guess is the
exhaust valves on the exhaust stator are broken. The pump needs repair or overhaul.
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| The pump is locked up
Well you gone and done it now. Check the pump for oil. Fill to
correct level and manually actuate pump, assuming you can. Sometimes it is possible to
manually actuate a pump back into service using the method described above. Other
potential problem areas include vanes stuck in up or out position. See "No
vacuum" section above. Call us if you are unsuccessful. The pump needs repair or
overhaul.
Oil Problems
Oil problems come in various shapes and styles and are highly
dependant on the vacuum pressure the user is trying to achieve. Because there are many
questions related to oil in our type of pumps we have a separate section just for oil
questions and tech support. Hot link to Oil Problems.
Oil in the System
We found oil from the pump inside our system when we came in this morning. Hot Link for
explanation and solutions.
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| Why is the pump leaking oil? Vacuum pumps can leak from 3 basic
locations and their causes can be various. The first area and main culprit to examine is
the shaft seal of the pump. This is a mechanically rotating shaft in an area that can wear
and then leak over time. Running the pump for a period of time on top of a sheet of
newspaper can pinpoint a leaks location.
The second most common location is from the pumps exhaust port. If the pump is operated
at high pressures less than 28" of mercury vacuum, then high gas flows create high
levels of lubricant agitation inside the pump which can exit the pump, come down the sides
of the pump and create what can be construed as a leak. If this is observed to be your
problem we can enclose the top of the pump and trap the exhaust of the pump using an
exhaust filter or by enabling the user to port the exhaust to a nearby "hood".
Sometimes adding an exhaust port extension using a section of standard plumbing pipe of
appropriate size and length 6-10" can help. This will help keep the oil and
associated oil mist inside your vacuum pump. The second solution is to make sure your
system is really, vacuum tight because the cause of this problem is basically a leaky
system. The pump will operate over extended periods with this symptom but it is important
to monitor the oil level of the pump on a regular basis.
Third is from a bad gasket or
O-ring. Solution is to replace the leaking part with a
new one.
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Water in the Pump Water in the Pump
Water in the Pump -
Hot link for the answers…. This is a big very common
problem. One of our most common problems is water in the pump.
Why is it bad? Corrosion. Pump destruction.
How does it happen? Waters vapor pressure less than pumps vacuum pressure.
How do I tell? Oil is milky colored.
What are solutions? Freeze those water molecules.
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| Pump is corroded. Why? Water or acids have been present in pump for an extended period of time. See also
water in the pump.
I think all high vacuum pumps are made from cast iron predominately, aluminum and steel
secondarily. We tried making one from stainless steel and will revisit sometime in future
but in a nut shell, it failed. Cast iron and water don't get along. This is the same for
acids like hydrochloric or sulphuric. The tend to attack the cast iron of the pump and
cause oxidation or rust to form. On the outside this is ok but left standing, formation
starts internal to the pump and will cause the pump to seize up after some period of time
days to years depending on contaminant source and level.
I have seen ads for corrosion resistant pumps. Right…., great marketing ploy. They
fail in 4 months instead of 3. Spend your money elsewhere on solutions that work. There is
no cheap solution only correct ones. Teflon coating… phooey. The vacuum pumps lock up
because the rust forms on the cast iron rotating parts "period". No
Teflon
coating is going to last long with the metal to metal contact that we have in rotary vane
pumps. Coating the oil sump with Teflon protects the aluminum housing. I have never seen a
pump yet with an uncoated aluminum housing eaten through, although I have seen thousands
of pumps with corroded cast iron parts.
The basic fact of the matter is contaminants must be
eliminated from the pump. You can either deal with it before the pump or after it gets in
the pump. For systems with high contamination potential then probably both types of
systems are required. For the front end or suction side of the pump, employ a vacuum inlet
trap. For dealing with contamination once it is in the pump consider an oil filtration
system that can be hooked up to the pump to recirculate and deacidify the oil.
The poor users solution to oil contamination problems "Change the oil
frequently". Create a larger oil sump that lasts longer in getting contaminated.
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| Why is the pump is slow to pull down? Assuming the pump is OK (see below). You have air leaks in your
system, collapsing vacuum hoses or contaminants which cause "out
gassing". Check
system for leaks (Link to procedures). Fix leaks and time again. Remove contaminants. |
How can I check my pump to see if it
is OK?
Hook you pump up to a
good vacuum gauge at the pump intake port with out the system attached in any manner. This
is the best and only real way to baseline the pump. In problem areas or troubleshooting
vacuum systems this is the first step in the process. Determine the "blank off"
pressure of the vacuum pump. For a 30 and 55L the blank off pressure is 15 micron or
.015mm and .1 micron .0001 mm respectively. For those with inexpensive vacuum gauges
roughly 20/7 micron, .020/.007mm with thermocouple or TC gauge. And for you real
misers
out there, 29.99 with Bourdon Tube 0-30" gauges and between 0 and 1mm with manometers
(0-760) in both cases depending on atmospheric pressure variables.
|
How do I
capture the exhaust?
The 30 and 55L vacuum only model pump requires only an
exhaust filter of correct pipe size that allows for capture of the exhaust fumes. This can
be ordered from HyVac for this use. As am alternative you then hook up an exhaust line and
port the exhaust to a hood or adapt it to an exhaust filter then to the hood. The 30 and
55L vacuum pumps all have an exhaust port as part of their design.
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My
hose nipple is too big / too small?
HyVac Products stocks and manufactures a myriad of solutions for conforming to a
users system. If we don't have it, we can get it. HyVac manufactures both conventional
hose fittings and also the newer generation quick disconnect vacuum fittings often
referred to as NW or ISO or KF fittings, flanges, piping, adapters and clamps which allow
a wide variety of connection sizes and terminations.
|
How do
I change the oil?
Generally
we recommend changing the oil through the exhaust port of any high vacuum pump. This port
generally is a straight dump into the oil sump of most vacuum pumps. The intake port
should only be used as a last resort, is slow but ultimately acceptable. Manual pump
rotation probably will be necessary to accomplish.
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| Other
problem areas not covered. You get em to me, I'll post
em. |
