894
NEWS
ED ITION
Vol. 19, No. 16
FOR CHEAP INSURANCE - - Use Wheelco LIMITROLS T h e cheapest insurance you can buy for your plant is Preventive Insurance. Wheelco Limitrols pro vide Preventive Insurance by protecting you against the losses excessive temperatures can cause in your processes. T h e Limitrol combines a high resistance pyrome ter with an electrically operated automatic shutoff device to give you (1) continuous, accurate, t e m perature readings, and (2) automatic shut-off of heat input when the temperature measured reaches a point selected and set on the pyrometer scale. T h e Limitrol may be used as a safety device to prevent temperature from rising above a danger point, or to insure shut-down of equipment, at any desired temperature, to obtain t h e exact material specifications required. Investigate
the applications
for Limitrols
in your
Diagrams below show typical methods of installing Limitrols.
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plant. Wheelco
Limitrol.
7 2 1 LIMITROL
LIMITROL FEATURES THERMOCOUPLE
SHUTOFF VALVE FOR FUEL FIRED FURNACE CONTACTORS FOR ELECTRIC FURNACE
i ALARM
V
L
ι
1 ο
Ο
I
1
Equipment cannot be turned o n again until t e m perature h a s dropped t o safe limit.
showing only.
Any point o n the scale can be selected as a shut-off point.
CONTROLLER
LIH
1
1
ο J
L
Ί
J
Protects equipment from being overheated due to failure of control or switching apparatus.
FURNACE ELECTRIC OR FUEL FIRED
Operating Diagram use of Limitrol 721 LIMITROL
Can be used i n conjunction with controllers of any type, or it can be used alone.
CONTROL SHUTO FF VAIU/ES FOR FUEL FIRED Ft WNACE CONTACHORS F O R E 1 E C T R C FUR!
