The
force required to move a load over a surface is the product of the
weight and the coefficient of friction. This resistance to movement
can be dramatically reduced by any method that reduces the coefficient
of friction.
One such method of reducing the frictional drag is to place a thin
film of fluid between the moving load and supporting surface. Air
because of its unlimited availability and general characteristics
is an ideal fluid. Since air buoyancy is omni-directional there are
no directional restraints (as in the case of belt or roller conveyors)
and loads can be rotated and/or moved in any direction with the same
effort.
As a result materials handling can be simplified and made considerably
more efficient. In fact, loads weighing hundreds and even thousands
of lbs. can be easily conveyed, positioned or maneuvered by one workman.
Ergonomics
Ergonomic Benefits of Air Conveying System:
Reduce work load on
operators
Reduces back, muscles
and skeleton injury
Improves worker efficiency
Increases worker productivity
while reducing their effort
Operation
Air,
or any fluid such as water in some cases, can be supplied to the nozzle
or table surface by means of hoses or a plenum. Different methods
are used to control the air flow to the supporting surface. Depending
on the application, the two principle methods are a porous medium
or a series of nozzles arranged in a particular geometric pattern.
Efficient air regulation is a key factor in the design of this type
of system of materials handling.
Two basic types of valves used in creating air table conveyors:
Series 200 (figure a) uses an "O"-Ring seal, metal ball and compression
spring. Valves are mounted with only the ball actuator protruding
above the table top.
Series 600 (figure b) is a low pressure economy version without "O"-Ring.
The ball can be either stainless steel, nylon or urethane.
Air
Nozzles
75 lb
Toolbox on Air Table
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To conserve the air supply while providing
optimum buoyancy, Glasgow Products has designed various nozzles based
upon the check-valve principle. These are mounted in a supporting
surface with a ball actuator protruding above the table top.
Air flows only when the load moves over the nozzle and depresses the
ball actuator. The entire air flow is directed and restricted to the
area beneath the load which serves as its own "switch" to automatically
turn the air On and Off.
Click on the images bellow to see the animation of Air Nozzle operation.
Vacuum
Applications
To securely clamp parts in place (using vacuum)
is readily accomplished.
Dual function nozzles using air pressure to buoyantly support and
convey and/or sequentially operated vacuum to securly clamp parts
in place may be incorporated.
A unique valve design permits blower output (air supply to system)
to be switched from pressure to vacuum in milliseconds merely by the
activation of a switch or lever by the operator.
Porous
Media
With a porous media Air Float
surface the entire table top becomes an air film surface
and the air flow is a function of the porosity of the
porous medium. Such systems are used where the moving
load may be too light to depress the ball actuator (approximately
4 oz.) or where the material being conveyed may not have
the rigidity (powders, viscous fluids, etc.) necessary
to depress the ball or where physical contact (e.g. painted
surfaces) is undesirable.
Stack
of Wood Floating on a
Porous Medium Table
Movie of a Thin Card (or Film) Floating
Above a Porous Medium Table
Irregular
Shaped Load Floating
on a Porous Medium Table
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