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EAU unsplit and EAS split externally-adjustable
seals offer complete containment of dry powders, pastes,
slurries, fluids, vapors and gases on a wide variety
of rotating equipment, where traditional packings fail
to seal. EAS seals are manufactured fully-split, permitting
installation and rebuilding without bearing or drive
removal.
One of the seal’s principal attributes is its ease of
operation. The seal face pressures are fully-adjustable;
there are no internal springs to loosen due to seal
face wear, or to corrode in hostile chemical environments.
All adjustment hardware is located outside the seal’s
purge cavity, so the seal can be adjusted with no disassembly,
often while the equipment continues to operate.
The EAS seal will accommodate significant radial and
angular shaft misalignment, as well as thermal growth
in high-temperature process machinery.
The EAS’s simple design allows easy disassembly and
lends itself particularly well to food and pharmaceutical
applications where the seal must be frequently sanitized.
Special versions of this seal are available which incorporate
sanitary design and manufacturing standards, permitting
easy removal, sanitizing, and reassembly.
How it Works
(Figure "A")
The seal incorporates separate inboard and outboard
stator housings, which are drawn together to compress
two seal rotors against a central driving elastomer.
The elastomer provides both positive pressure to the
seal faces and a firm grip around the circumference
of the shaft. As the driving elastomer rotates with
the shaft, the two seal rotors turn with it.
A circle of adjusting studs connects the two housings,
which contain the inboard and outboard stator surfaces.
The inboard stator housing, with its adjusting studs,
is bolted flat against the machinery bulkhead or stuffing
box. Nuts on the ends of the adjusting studs are used
to precisely control the gap between the stator housings,
controlling the internal seal face pressure. A special
gauge is furnished for measuring this gap.
Two seals are formed at the interfaces of the rotors
and stators. The driving elastomer’s tight grip against
the shaft prohibits material from leaking along the
length of the shaft.
An adjusting gasket permits the gap between the two
stator housings to be varied, while containing a purge
medium within the seal. The seal can be purged with
air, inert gas or fluids, depending on the process involved.
Use of various materials permits the EAS to be built
to withstand a wide range of physical and chemical environments.
The stator housings are built from one of a variety
of metals, depending upon the application. The stators
and rotors are manufactured from stainless steel or
bearing plastics. Materials are available to withstand
process temperatures of up to 500° Fahrenheit (260°
Celsius).
The EX-PAC
variation of the seal incorporates the EAS-style rotor
assembly in a stuffing box-style housing, for higher
pressure retention. Both The EX-PAC and EAS seals can
be fitted with a mechanical drive mechanism for high
pressure service and to accommodate severe axial shaft
movement. The EX-PAC seal can also be designed for spring
adjustment, or for pneumatic adjustment, permitting
remote control over the seal face pressure.
Installation
In many instances, fully-split EAS seals can be installed
in as little as a few hours, once the packing gland,
packing and lantern ring have been removed. A variety
of mounting adapter plate configurations permits mounting
to the existing gland bolts on most equipment with no
modification.
Where installation clearances are severely limited,
it is occasionally advantageous to move or relocate
the shaft sleeve, modify the gland bolt arrangement
or remove the stuffing box.
Applications The EAS is custom-designed
and manufactured to each application. MECO normally
incorporates 1/4" (6mm) of total runout/ misalignment
capacity in EAS seal designs. Where needed, more runout
capacity can usually be provided.
While originally designed for a bottom entry paper pulper
application, the EAS is now in service on a wide variety
of equipment in the chemical, plastics, food, pharmaceutical
and biotechnology industries, as well as in pulp and
paper applications.
EAS seals are operating on paper stock agitators under
up to 110’ (43 1/2 meters) of product. They have provided
reliable service on ribbon blenders, polymer dryers,
solvent extractors, extruders, conveyors and agitators
of all types. Seals for shafts up to 28” (711mm) in
diameter are in operation.
EAS seals contain a broad array of products and materials,
from dry powders of all types to cheese and liquid chocolate,
ibuprofen, tomatoes, dry milk products, hot cooking
oil, human blood plasma, fruit juices, hydrocarbon gases
and solvent vapors. Many MECO seals containing aromatic
hydrocarbons are "sniffed" and are documented as producing
50PPM emissions.
MECO and its distributors work with clients’ maintenance
and production personnel to custom-design seals tailored
to each individual need.
The EAS and other MECO seals are offered for a wide
variety of applications, from screw conveyors to most
other process machines. Your MECO distributor will work
with you to create a solution tailored to your needs.
Ordering Information
MECO seals are custom-designed to
each application. Your local distributor can help you
with the application process, collecting the dimensional,
product and process information needed.
When ordering any EAS-series seal,
it is essential that information be supplied concerning
the shaft diameter, RPM, operating temperature and pressure
and what material is being processed, as well as whether
the shaft is horizontal, inclined or vertical.
Should you require additional information,
or the name of the authorized MECO distributor in your
area, please don’t hesitate to call.
Product Literature
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