![Rosemount 1199 Скачать руководство пользователя страница 16](http://html.mh-extra.com/html/rosemount/1199/1199_reference-manual_1487371016.webp)
Reference Manual
00809-0100-4002, Rev BB
November 2012
Rosemount 1199
2-6
NOTE
Temperature effects were calculated in Instrument Toolkit using a 2-in. (DN
50) FFW seal, Silicone 200, 10 ft. (3 m) between the taps, over a 50 °F (28
°C) temperature change.
SPECIFYING THE RIGHT
SOLUTION FOR
VACUUM
APPLICATIONS
Vacuum Application
Overview
When a vessel is under a vacuum pressure, it is important to specify the
correct transmitter remote seal system to measure level accurately and
reliably. Failure to do so can result in output drift or complete system failure.
The combination of high process temperature and vacuum process pressure
conditions creates additional requirements when specifying the transmitter
remote seal system.
Vacuum Applications
There are three primary transmitter-seal system components necessary to
successfully specify vacuum application solutions:
•
Transmitter Mounting Position
•
Fill Fluid Selection
•
Seal System Construction
Seal System Construction for Vacuum Applications
Emerson offers Rosemount 1199 seal assemblies, welded-repairable, and
All-Welded vacuum system construction. In vacuum applications below 6 psia
(310 mmHga), specify the All-Welded vacuum construction. Gasket
connections allow the potential for vacuum pressure to draw air into the
capillary system causing drift or complete system failure. No air in the system
eliminates the need to re-zero and thus improves plant availability by
preventing unscheduled downtime and instrument repair or replacement.
The all welded vacuum construction was designed specifically for vacuum
applications. In this construction, the sensor module gaskets are removed
and a disk is welded over the sensor isolators. This eliminates the possibility
of air being drawn into the seal system in deep vacuum conditions. This
premium design is strongly suggested for vacuum pressures below 6 psia
(310 mmHga).
Transmitter Mounting
Position
Mounting the pressure transmitter at or below the bottom vessel tap is an
important factor to ensure a stable measurement with vacuum applications.
The static pressure limit for a differential pressure transmitter is 0.5 psia (25
mmHgA), which ensures the transmitter sensor module fill fluid remains within
the liquid phase of the vapor pressure curve.
If the vessel static limit is below 0.5 psia, mounting the transmitter below the
bottom tap provides a capillary fill fluid head pressure on the module. A
general rule is to always mount the transmitter approximately 3 ft. (1 m) below
the bottom tap of the vessel.
Содержание 1199
Страница 2: ...This page intentionally left blank ...
Страница 4: ...This page intentionally left blank ...
Страница 8: ...Reference Manual 00809 0100 4002 Rev BB November 2012 Rosemount 1199 TOC 4 ...
Страница 20: ...Reference Manual 00809 0100 4002 Rev BB November 2012 Rosemount 1199 2 10 ...
Страница 38: ...Reference Manual 00809 0100 4002 Rev BB November 2012 Rosemount 1199 3 18 ...
Страница 60: ...Reference Manual 00809 0100 4002 Rev BB November 2012 Rosemount 1199 5 10 ...
Страница 81: ...This page intentionally left blank ...