
2.5.5
Fill fluid selection
When the process is under vacuum conditions, the fill fluid can vaporize at a lower
temperature than when it is under normal atmospheric or greater pressure. Each fill fluid
has a specific vapor-pressure curve. The vapor-pressure curve indicates the pressure and
temperature relationship where the fluid is in a liquid or a vapor state. Proper seal
operation requires the fill fluid to remain in a liquid state.
For vacuum applications, specify fluids that are specifically designed for use in these types
of applications such as Silicone 704 for vacuum applications, Silicone 705 for vacuum
applications, or UltraTherm
™
805 for vacuum applications. These fluids have been
specially processed to deliver the maximum vapor pressure curve performance possible.
For more information on Rosemount Diaphragm Seal fill fluids, reference the Rosemount
1199 Fill Fluid Specifications
.
2.6
Diaphragm weld types
Weld-type is factory-determined as best for the seal typed specified. PFW and FFW seals
have ordering options that specify welding options.
2.6.1
Solid faceplate design
The solid faceplate design is used when diaphragm and upper housing material are the
same.
A
B
A
C
D
A. Material A
B. Upper housing
C. Diaphragm
D. TIG weld point
Reference Manual
Remote Seal Systems
00809-0100-4002
May 2020
Rosemount DP Level
15
Summary of Contents for Rosemount 1199
Page 4: ...4 ...
Page 8: ...Introduction Reference Manual May 2020 00809 0100 4002 8 Rosemount DP Level ...
Page 22: ...Remote Seal Systems Reference Manual May 2020 00809 0100 4002 22 Rosemount DP Level ...
Page 74: ...Installation Reference Manual May 2020 00809 0100 4002 74 Rosemount DP Level ...
Page 92: ...Fill Fluids Reference Manual May 2020 00809 0100 4002 92 Rosemount DP Level ...