Static Electricity 2000 Edition

Impregnating;
spreading
*
*
*
Coating
roll
Coating
operations
Coating
material
*
*
Gravure
roll
A static
neutralizer is not
necessarily
needed here
¹⁄₄ in. minimum
1 in. maximum
*
*
*
*
*
4 in. to 6 in.
Printing and other
gravure operations
*Suggested locations for static neutralizers.

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77–
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STATIC ELECTRICITY
2000 Edition
belt will diminish. In either case, belts should be kept free of
accumulations. It should be noted that both conductive and
nonconductive belts can generate and deposit charge on the
material or objects being conveyed.
9.4.2.3
An electrostatic neutralizer placed so that the points
are close to the inside of the belt and a few inches away from
the point where the belt leaves the pulley will also be effective
in draining away most of the charge. (See 9.2.5.3.)
9.4.3* “V” Belts.
V belts are not as susceptible to hazardous
accumulations of static electric charge as are flat belts. Under
certain conditions of temperature and humidity, however, a V
belt can generate a significant charge. Where ignitible mixtures
of gases, vapors, dusts, or fibers are present, the preferred
method to limit ignition by static electric discharge is to use a
direct drive instead of a belt. If a V belt is necessary for other rea-
sons, it should be protected in accordance with 9.4.2.2.
9.4.4 Conveyor Belts.
9.4.4.1
Belts used for the transport of solid materials usually
move at speeds that are slow enough to prevent an accumulation
of static electric charges. However, if the material being trans-
ported is very dry or if the belt operates in a heated environment
and at high speeds, significant charges can be generated.
9.4.4.2
Material that is spilled from the end of a conveyor belt
into a hopper or chute can carry a significant charge. In these
cases, the belt support and terminal pulleys should be electri-
cally grounded or bonded to the hopper or chute. A passive or
active neutralizer installed close to the end of the conveyor can
also help reduce the charge. Conductive or antistatic belts can-
not be expected to remove static from the conveyed product.