Ashcroft t5500e Manuel d'instructions pour l'installation et l'entretien - Page 4
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2 Safety
2.1 General sources of hazards
Pressure gauges are pressurized instruments where failure can result in hazardous situations. The selection of
pressure gauge should be made in accordance with the rules set out in EN
damage may be caused by excessive overpressure, excessive vibration or pressure pulsation, excessive instrument
temperature, corrosion of the pressure containing parts, or other misuse. Consult the manufacturer before installing if
there are any questions or concerns.
2.1.1 O
verpressure
Pressure spikes in excess of the rated overpressure capability of the transducer may cause irreversible electrical
and/or mechanical damage to the pressure measuring and containing elements.
Fluid hammer and surges can destroy any pressure transducer and must always be avoided. A pressure snubber
should be installed to eliminate the damaging hammer effects. Fluid hammer occurs when a liquid flow is sud
stopped, as with quick closing solenoid valves. Surges occur when flow is suddenly begun, as when a pump is turned
on at full power or a valve is quickly opened.
Liquid surges are particularly damaging to pressure transducers if the pipe is originally empty. To avoid damaging
surges, fluid lines should remain full (if possible), pumps should be brought up to power slowly, and valves opened
slowly. To avoid damage from both fluid hammer and surges, a surge chamber should be installed.
Symptoms of fluid hammer and surge's damaging effects:
•
Pressure transducer exhibits an output at zero pressure (large zero offset).
•
Pressure transducer output remains constant regardless of pressure
•
In severe cases, there will be no output.
2.1.2 Freezing
Prohibit freezing of media in pressure port. Unit should be drained (mount in vertical position to prevent possible
overpressure damage from frozen media.
2.1.3 Static electrical charges
Any electrical device may be susceptible to damage when exposed to static electrical charges. To avoid damage to
the transducer observe the following:
•
Operator/installer should follow the proper ESD (electrostatic discharge) protection procedures before
handling the pressure transducer components.
•
Ground the body of the device BEFORE making any electrical connections
•
When disconnecting, remove the ground LAST!
The shield and drain wire in the cable (if supplied) is not connected to the transducer body, and is not a
suitable ground.
2.2 Use in accordance with intended purpose
The devices are only to be used for the intended purpose as described by the manufacturer.
The devices are used for direct display of overpressures, vacuum and compound pressure and for transmission of
overpressures, vacuum and compound pressure into a standard electrical output signal.
For each use scenario, the corresponding set-up regulations must be respected.
The usage in explosion risk areas is not allowed.
2.3 Operator's responsibility
Safety instructions for proper operation of the device must be respected. They are to be provided by the operator for
use by the respective personnel for installation, servicing, inspection and operation. Risks from electrical energy and
from the released energy of the medium, from escaping media and from improper connection of the device must be
eliminated. The details for this are to be found in the corresponding applicable set of regulations, such as DIN EN,
UVV (accident prevention regulations) and in sector-specific instances of use (DVWG, Ex-. GL, etc.) the VDE
guidelines and the regulations supplied by local utilities companies.
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837-2.
A failure resulting in injury or
denly