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The Shand & Jurs Type JB3704 Limit Switch Assembly is designed for mounting on Shand &
Jurs 92302 Liquid Level Indicator. Type JB3704-1 is for indicators using metal gauge
boards. Type JB3704-2 is for indicators using wood gauge boards.
For high or low level alarm, pump start and stop control and a variety of signaling or other control
services, the switch provides positive action in an explosion-proof housing. One or more of these
assemblies may be mounted on the gauge board, each having one mercury tube switch in each
switch box, (two when specified). One limit switch assembly is required for each alarm point (i.e.
two are required for high and low, etc.). As the target reaches the high, low or intermediate switch,
the operating pin engages the operating arm.
The arm movement rotates the shaft and trips the mercury tube switch or switches. The switch
remains in this position until the tank level rises or falls sufficiently for the target operating pin to
re-engage the operating arm, and automatically resets the switch to the previous position. The
operating arm does not interfere with target movement above or below the switch.
The switch may be field repositioned on the operating shaft to be normally open or normally
closed as the user requires. Two switches can be put in any configuration including: one open,
one closed; both open or both closed.
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