Parr Instrument Series 4560 - Manual (Page 14)

Mini Bench Top Reactors
P a r r I n s t r u m e n t C o m p a n y 14
1. The Motor
The standard variable speed motor is not explo-
sion proof, yet these motors are not unduly haz-
ardous if operated in a well ventilated location
where care is taken to prevent the accumulation
of explosive gases or vapors. To eliminate any
possible spark hazard originating at the mo-
tor, Parr can furnish an air motor as described
previously, or the reactor can be equipped with
a variable speed, explosion proof motor which
is approved for use in Class 1, Div. 1, Groups C
& D, and Class 2, Groups E, F, & G atmospheres.
Explosion proof motors are furnished with a
temporary power cord and plug which are not
explosion proof. The user should remove this
temporary wiring and replace it with an explo-
sion proof switch and wiring which will comply
with the local electrical code.
2. The Temperature Controller
The Temperature Controllers furnished with
these reactors contain switches and other ele-
ments which are not explosion proof. The mini-
mal spark hazard associated with these units
can be resolved by installing the controller in a
remote location outside of the hazardous area or
by enclosing it in an approved explosion proof
housing. If enclosed within a positive pressure,
clean air housing, the discharge from the hous-
ing must be directed into a safe area. If request-
ed, Parr will furnish the long lead wires needed
to mount the controller in a remote location. If
the controller is to be installed in an explosion
proof housing, the user must provide the neces-
sary housing and installation.
3. The Heater
The elements in the heater could be dangerous
in an explosive atmosphere if the surface tem-
perature of the element becomes high enough
to ignite fl ammable vapors. This hazard must be
evaluated for each individual installation since
major modifi cations are required if the heater
must be isolated from the surrounding atmo-
sphere. Users who consider this a signifi cant
hazard are urged to contact the Parr Instrument
Company for further discussion and suggestions
which might be helpful. Parr is currently offering
aluminum block heaters and circulating jacketed
cylinders which can be used in hazardous envi-
ronments.
4. The Wiring
Unless specifi cally designed for use in hazard-
ous atmospheres, the wiring in these reactors
will not meet the standards prescribed for explo-
sion proof equipment. Optional intrinsically safe
barriers are also available.
Explosion Proof Operation
If the local safety code requires that equipment installed in the user’s laboratory must be explosion proof
there are four possible ignition hazards to be considered: