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A Hydraulic Fuse is
similar to an electrical fuse or circuit breaker found in our homes.
You may have had to find the fuse box and reset or replace a blown
fuse. This happened because the electrical circuit was overloaded and
the capacity for carrying electrical current was exceeded. This condition
can cause overheating of the circuitry or wiring, the fuse senses the
overload and disconnects the electrical circuit effectively shutting it
off. In this way, further equipment damage is eliminated and a potential
safety hazard is avoided.
The Hydraulic Fuse
provides similar protection to a hydraulic circuit. A Hydraulic Fuse
is used to detect a leakage condition (such as a broken line or a
disconnected hose) and shut off the circuit reducing the loss of
fluid. A good definition of a Hydraulic Fuse is:
"A device used
as a safety measure in hydraulic systems to prevent fluid loss."
A Hydraulic Fuse is
a shut-off valve that actuates (closes) when a predetermined condition has
occurred. Depending on the type of hydraulic fuse specified, this condition
may be a sudden change in pressure or flow. The fuse shut-off may also be
triggered when a specific quantity of fluid has been sensed.
History has shown
that if hydraulic fuses had been used, lives and equipment could have been
saved. In addition, expensive environmental clean-up could have been
avoided.
Why haven't
hydraulic fuses been used?
Cost seems to be the
main objection, even when the price of a fuse is less than $100.00.
It is the same reason seat belts were not voluntarily installed in
automobiles, it cost too much. It was not until the Government made
it mandatory that seat belts were installed in every automobile. The
same may be needed to mandate hydraulic fuses, especially in lifesaving
applications, i.e. airplanes, cranes, lifts, elevators, etc. Again,
just like wearing a seat belt doesn't guarantee to save your life in an
accident, the odds of surviving the accident are much better when this
safety device is securely in place.
In addition to the
cost impact, there are other reasons for the reluctance of adding fuses to
hydraulic circuits:
1.) Nuisance trips
may occur (the fuse closes when it is not supposed to). These can be
overcome by selecting the proper type of fuse for the application and
choosing the correct size that matches the characteristics of the hydraulic
circuit being protected.
2.) Not stopping a
slow leak. Generally, hydraulic fuses guard against catastrophic
failures. Again, selecting a quantity fuse may work in a slow leak
application.
In summary, when
selecting a hydraulic fuse it is important to have a clear understanding of
the operation of the hydraulic system. Select and apply the proper type of
hydraulic fuse with the correct rating for maximum protection.
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