Siemens ET 77E Series Especificaciones descargar pdf (Pagina 25)

SD77

Metric Housing Standard Housing with Adapter

FIGURE 2-4 Transducer Housings for Metric Conduit

2.2 INSTRUMENT AIR REQUIREMENTS

Connect the transducer to a source of clean, dry, oil-free instrument air. Failure to do so will increase the possibility

of a malfunction or a deviation from specified performance.

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 the 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

the approval certificate.

The requirements for a quality air supply can be found in the Instrument Society of America's "Quality Standard for

Instrument Air" (ISA-S7.3 or BS5967: Part 2). 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 (35.5°F).

Oil Content: The maximum total oil or hydrocarbon content, exclusive of noncondensibles, should not exceed 1

ppm under normal operating conditions.

Recommended supply pressure is listed in Section 1.2 General Specifications.

Caution

Supply pressure in excess of the specified maximum may cause damage.

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Siemens ET 77E Series Especificaciones Pagina 25