Weksler diaphragm seals are suitable for use with
bourdon tube type pressure gauges, recorders, transmitters, etc.
Used as an attachment, the thin flexible diaphragm serves as a
separating member stopping the medium from entering the gauge
thereby preventing clogging and corrosion. Weksler diaphragm
seals can be mounted directly to the instrument or remote connected
with stainless steel seamless or armored capillary tubing.
Considerations in Selecting a Weksler
Diaphragm Seal
Warning: All seal components should be selected
considering process and ambient operating conditions to prevent
misapplication. Improper application could result in failure and
possible injury or property damage.
Top Housing:
The top housing includes a connection for the
pressure instrument and may support the upper surface of the
diaphragm. Since this component is not in contact with the process
fluid, it is commonly made of steel. However, if the external
atmosphere contains corrosive elements, other materials like 316 SS,
may be required.
Diaphragm:
The diaphragm separates the bottom housing from
the fill fluid. The diaphragm material must be compatible with the
process fluid. Because of its thin cross-section, special attention
must be given to diaphragm material selection. Operating
temperatures must not exceed the limit for the material used.
Bottom Housing:
The bottom housing material is in direct contact
with the process fluid and must therefore be compatible with the
process fluid.
Some Weksler models are offered with a flushing
connection.
This feature offers a method or purging the seal
cavity or a means of back flushing foreign material from the process
connection. (Not available with plastic lower housings.)
Fill Fluids:
The fill fluid must be capable of withstanding
operating process temperature. Glycerin or silicone can combine with
strong oxidizing agents such as oxygen, chlorine, nitric acid and
hydrogen peroxide causing fires or violent reactions. Seal
assemblies intended for such applications should be filled with an
inert fluid such as Halocarbon. Seals intended for use with oxygen
must be manufactured completely free of oil.
Pressure Rating:
The maximum allowable pressure for the seal
selected must not be exceeded. Weksler flange seals are generally
limited to the maximum rating of the flange itself. Plastic bottom
housings will not withstand the same pressures as metal equivalents.
Maximum allowable pressures for all materials decrease as
temperatures increase. Note: Maximum vacuum indication may not
exceed 25˝ Hg. Consult Weksler Customer Service if higher vacuum
indication is required.
Accuracy/Temperature Errors:
The addition of a liquid filled diaphragm seal to
an instrument will degrade its accuracy by 0.5% (maximum). In
addition, changes in ambient temperatures will introduce temperature
errors because of the expansion/contraction of the fill.
Leaks:
The entire filled portion of the system must be
absolutely leak tight, since any loss of fill will result in
significant errors.
