UM91-HF
Installation Dimensions
WARNING
As with any pneumatic device, excessive
pressure will eventually cause one or more
components to rupture. Such an event could
cause death or serious injury. To avoid this
possibility, the supply (IN) pressure must not
exceed 150 psig.
IMPORTANT
The Model 91-HF filter regulator has low capacity internal relief,
which provides very limited downstream over-pressure protection.
To avoid exceeding the output pressure limits in service, a pressure
relieving or pressure-limiting device should be provided.
INSTRUMENT AIR REQUIREMENTS
This product is intended for use in industrial compressed-air systems
only. Do not use this product where pressures and temperatures can
exceed those listed under Specifications.
CAUTION
Use of process fluids other than instrument air is not recommended. No claim is made as to the
suitability of this product for use with other process fluids, such as hazardous gases, except as listed
on an appropriate certificate. Non-approved instruments are suitable for use with instrument air
only. Optional features and modifications such as tapped exhaust do not imply suitability for use
with hazardous gases except as listed on an approval certificate.
CAUTION
Synthetic compressor lubricants in the instrument air may cause deterioration of some
components resulting in instrument failure. See materials of construction above.
The requirements for a quality instrument air supply can be found in the Instrument Society of America's "Quality Standard
for Instrument Air" (ISA-S7.3). Basically, this standard calls for the following:
Particle Size — The maximum particle size in the air stream at the instrument should be no larger than 3 microns.
Dew Point — The dew point, at line pressure, should be at least 10°C (18°F) below the minimum temperature to which any
part of the instrument air system is exposed at any season of the year. Under no circumstances should the dew point, at line
pressure, exceed 2°C (35.6°F).
Oil Content — The maximum total oil or hydrocarbon content, exclusive of non-condensable, should not exceed 1 ppm under
normal operating conditions.
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