The molecular sieve trap is a foreline trap which
employs synthetic zeolites (molecular sieve (13X) as an absorbent. The
large surface area of the 13X) sieve, and its large pore size of 10 to
13 angstroms produce excellent absorption of water and oil vapor and
other larger gas molecules found in the vacuum line. Molecular sieve
traps have been in use since the early 1960's. They were used to prevent
oil back streaming and reduce the base vacuum limited by water vapor. A
typical application was to start a sputter-ion pump at room temperature
when the use of a sorption pump was not practical. Today, the trap when
used properly is still very effective in reducing or preventing
back-streaming from rotary vane pumps and is very widely used.
Continuous Trapping of a Molecular Sieve Trap
To provide continuously trapped pumping it is
suggested that two traps be used in parallel. In this way one trap can
be re-activated (baked-out) while the other trap is being used. A small
auxiliary pump can be used to pump out the saturated trap during
bake-out. Re-activation can also be accomplished by replacing the
molecular sieve with a fresh replacement charge.
HyVac replacement charges are pre-baked and ready to use. Eventually,
the sieve charge should be replaced as there is some oil residue that
becomes baked on. Suggested
sieve charge replacement is every year or after 10 bake-outs.
The molecular sieve trap will provide one of the best oil vapor
attenuation factors for a trap not requiring liquid nitrogen. These
traps will also lower the base vacuum attainable with an un-trapped pump.
In order to maintain this performance, proper operation and maintenance
is required. With all traps and pumps, there is no hard and fast rules
for reconditioning and maintenance.
Therefore, close observation of performance parameters and
replacement materials will be the best guide in a vigorous maintenance
HyVac Products, Inc. manufactures mechanical vacuum pumps, gauges,
traps, filters and supporting components for most every application and
supports a network of qualified dealers to help you.
#1 & #2
Molecular Sieve charges are
#1 Heater is 115 VAC 75 Watt.
#2 Heater is 115 VAC 125 Watt.