|
|
|
What
is a Diaphragm Seal? |
 A
Diaphragm Seal is a device consisting of a diaphragm firmly clamped
between two suitable flanges and properly gasketed to prevent leakage
of liquid or gas. In this type of device a diaphragm, which is a
"dividing membrane or a thin partition", acts as a barrier to a
liquid or gas that may tend to clog or corrode the sensing element
in a pressure instrument and therefore render the pressure instrument
useless. This type of device is sometimes called a chemical seal
or gauge protector.
DIAPHRAGM SERIES
The Versa Diaphragm Seal is available in two basic sizes - a small
size and a large size. The small size is the 100 & 300 Series Seals
and the large size in the 106 & 306 Series Seals. The difference
between the two Series is that the 106 & 306 effective diaphragm
area used by the 100 & 300 Series. Therefore, the 106 & 306 should
be the choice for all sensitive and low-pressure applications.
 CONTINUOUS
TYPE
All the 100, 106, 300 and 306 Series diaphragm seals are continuous
type for safety. This is especially important when a diaphragm seal
is used in a hazardous application. With this type of construction
the diaphragm will aid in containing the process media should the
pressure instrument be accidentally broken or removed. This is very
important should the process media be either corrosive or a harmful
gas. This also, allows the process to continue to run until a convenient
time to shut down the process line and replace the damaged pressure
instrument.
DIAPHRAGM SEALS
- Special Features
CLEANOUT TYPES
All seals are of the cleanout type except the 100A or 106A. The
bolts of the cleanout type can be removed and separated at the flanges
for cleaning, liquid filling, calibrating, welding, or other purposes,
without the loss of liquid fill fluid.
NON-CLEANOUT TYPES
The bolts of the non-cleanout style (100A or 106A) MUST NOT
be removed. Loss of liquid fill fluid will result, as the diaphragm
is NOT held in the instrument flange.
FILL/BLEED PORT
All seals come standard with a Fill/Bleed port. This tapped
hole in the instrument flange gives access to the fill area above
the diaphragm. This port is used for filling the pressure instrument/seal
combination and for bleeding excess fluid from the system.
TYPE 300 & 306 WELDED METAL DIAPHRAGM
In this type of seal the metal diaphragm is welded at its periphery
to the instrument flange. The advantage of using this type of seal
is that it will retain the liquid fill fluid with less danger of
leakage. It is very popular because of this feature and is usually
the lowest in cost. This type of seal is classified as a throw away
type because it cannot be repaired if the diaphragm is damaged or
worn out; therefore, it must be replaced with a new diaphragm seal.
All welded seals are of the cleanout type.
TYPE 100 & 100B WELDED METAL DIAPHRAGM
In this type of seal the diaphragm can be replaced if worn out
or damaged. The seal can be rebuilt many times, thus restoring it
to a”LIKE NEW”condition and lowering the cost. For this type of
seal to be the cleanout type, you must use the 100AC which
has a snap in diaphragm allowing the flanges to be separated without
loss of fill fluid. The 100A is NOT a cleanout type Seal.
TYPE 100 & 100B WITH VITON DIAPHRAGM
Viton diaphragms are suitable for use with extremely low pressures
and high vacuums. In the cleanout style, the diaphragm is bolted
to the instrument flange. In the non-cleanout style, the diaphragm
is bolted between the flanges.
TYPE 100 & 100B WITH TEFLON DIAPHRAGM
The Teflon diaphragm seal is truly the top of the line of diaphragm
seals regardless of manufacturer and many have discovered that the
Versa Seal is superior. This type of seal is very forgiving due
to abuse or error. |
|
