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Use in Hazardous Locations
Type of protection "i" intrinsic safety
The pressure switches to be used in hazardous locations are principally designed for intrinsically
safe circuits i following the applicable regulations and are provided with a blue plate bearing the
words "For intrinsically safe Ex i application".
They must be operated with a switch amplifier as shown in Fig. 6. They are only for use in approved
intrinsically safe circuits.
Switches with explosion-proof enclosures must be operated in accordance with their approval.
Approval class and identification characteristics according to type plate information must always be
observed.
EC-design approved types are marked with a type plate according to ATEX 94/9/EC.
The wiring between switch and Ex i isolation amplifier must meet the local safety requirements.
The customer must provide for a highly conductive connection between switch and grounding.
Unprotected area
Zener barrier type
Switch amplifier NAMUR
Fig. 6: Operation of pressure switches in intrinsically safe areas
Type of protection "d" explosion-proof enclosure
The pressure switch with enclosure is suitable for Ex d applications.
The "flying leads" are intended for a conduit connector. Free wiring of the leads without protection
(e. g. without terminal box - Article no.: 926-0811) is not permissible.
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Ex ia area
c
NO
NC
GRD
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Maintenance/Cleaning
Maintenance
The pressure switch is maintenance free, however, the country specific test intervals for preventive
maintenance in plants, the PED guideline are to be carried out at all times. Checking the set points
lies within the discretion of the user.
Small setpoint drifts may occur during the initial use of the switch (run-in period). To minimize the
setpoint drift we can perform a run-in (ageing) process in our works on request. Larger or
continuing setpoints drifts during the normal use of the switch may indicate that the measuring
system is not used correctly within the specified limits, exceeding the design criteria or is worn-out.
This might lead to metal fatigue of the measuring system and it therefore should be replaced
before an ultimate rupture of the metal diaphragm might take place. Please consult your supplier or
Barksdale directly for guidelines.
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Technical Data
See data sheet
Dimensions
in mm (inch)
38 (1.5)
Fig. 7:
Dia-seal piston sensor type 9671X/9681X
3x 18" conductors
(450 mm) and
1x ground per circuit
(for single circuit,
7x for dual circuit)
½" NPT
connector
Adjustment
wheel
Ground
screw
Mounting
holes only
on model K
Pressure connection
19.1 (0.75)
29 (1.125)
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