ROLLING BLADE®
Cleveland
Armstrong's® patented Rolling Blade® gate incorporates a
camming of the blade into the seal for a positive cutoff. There are various
versions of this gate. The Rolling Blade® has these
features:
- Standard black neoprene seals
- Fast acting Rolling Blade®
- Wiper seal
- Cutoff wall seal
- Cam action closing for positive
sealing
Diagram 1 |
Diagram 1. Full open position of the ROLLING BLADE® unit: Note distance between side seal and blade. The center of the blade curvature is fractionally offset from the center of blade rotation for cam action. |
Diagram 2 |
Diagram 2.
Partially closed position: Offset center of rotation (cam
action) causes blade to rise while moving to closed position. In this
position the space has been reduced by one-half between the side seal and
blade. |
Diagram 1 |
Diagram 3. Fully closed position: the offset center of rotation (cam action) forces the blade up and against the side seals. During the entire closing cycle, the friction and wear from side seal drag have been minimized. |
ROLLING BLADE® FEATURES
One feature is the ability to generate a superior seal
due to the compression of the seals as the blade nears the closed position. In a
non-cam action design, the pressure or preload of the seals is constant
throughout the travel of the blade. In order to prevent seizing of the blade by
the seals, it is impossible to highly load the seals against the surface of the
blade. The cam action design provides high seal loading but only at the point of
full closure, when it is needed the most.
The cam action also compensates for
irregularities in the seal or blade surface. This is a result of our ability to
highly load the seals with the cam action. The net result is we can assure our
customers of superior sealing over conventional rolling blade design.
Another feature which goes hand-in-hand with the
first, is a dramatic reduction in seal wear. This is a result of the blade being
able to travel beneath the seals without making contact or with limited contact
of the seals during the opening and closing movement. High seal loading occurs
only prior to full closure of the blade. Conventional designs require the seal
force remain constant throughout the entire opening and closing movement of the
blade.
If seal life and the ability to assure a
positive seal is a requirement of your application, then certainly, the cam
action design is superior.
PEBCO®'s standard design incorporates the use of these externally
mounted bearings. Many of PEBCO®'s competitors utilize the sleeve bearing design or simply shaft collars.
PEBCO® has always strived to
design and manufacture equipment for long life, heavy use, and ease of
maintenance. The externally mounted bearings allow for minimum exposure of the
bearing seal to the product. It also improves accessibility of the bearing for
relubrication and in the event of replacement, removal and replacement of the
bearing.
We use industry standard mounted bearing
configurations. This allows interchangeability among many of the bearing
manufacturers. This is often a big advantage if only one or two manufacturers
are represented in the area the gate is located.
Life is greatly improved due to the use of the
anti-friction roller bearings in lieu of sleeve bearings or steel collars.
Efficiency of operation is also improved since the force generated by the
actuator is used to overcome the opening and closing resistance of the product
on the blade; with only a small portion contributing to the force required to
overcome bearing friction. This is in lieu to the much higher forces required to
overcome breakaway force associated with sleeve bearings and steel
collars.
ROLLING BLADE®
BENEFITS
PEBCO®'s best
sealing gate against product leakage and dust leakage, is the ROLLING
BLADE® design which offers the following benefits:
- ROLLING BLADE® can
cut through a standing column of material.
- Seals on top, bottom, and side of the gate;
these help provide a seal for pressure or vacuum applications.
- Cam action used during blade closure. This
action forces the blade up into the seal at the closure point rather than
running the blade along the seal. The end result is a tighter seal with a
longer seal life and superior sealing on pressure and vacuum
application.
- Outboard bearings are used to protect the
bearings from material contamination and provide a better
shaft
seal.
- Curved blade design allows the gate to be
used as a metering valve.
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