KROHNE OPTIMASS with MFC 300 EN - Manual (Page 39)

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Note :
The outer casing is in contact with the heating medium.
6.4 Secondary Pressure containment
The OPTIMASS 3000 meters are supplied with secondary pressure containment as standard.
The maximum secondary containment pressure (as certified) is 30 barg at 20°C (435 psig at
70°F), de-rated as follows :
The de-rating is based on the reduction of material strength with temperature for 316L (W No.
1.4404) material from DIN 17456.
Heating jacket is rated to 10 barg at 150°C (145 psig at 300°F).
If a heating jacket fitted, secondary containment is limited to 10 barg at 150°C (145 psig at
300°F). This is because the jacket is fitted inside of the secondary containment dome.
If the meter operating pressure is higher than the secondary containment allowable pressure
then a relief or bursting disc option (fitted in the dome) MUST be ordered. In this case the
meter data plate is stamped with maximum pressure rating (at 20°C and maximum operating
temperature) of the connection or the primary tube (whichever is the lower).
If the user suspects that the primary tube has failed, the unit must be depressurised and
removed from service as soon as it is safe to do so.
Notes:
• In the 3000 series there is a high pressure wire feed through with ‘O’ rings that might not be
compatible with the process fluid for an extended period if a primary tube fails.
• It is the user’s responsibility to ensure that the materials used are compatible with this
product.
• Other ‘O’ ring materials are available on request.
• Burst disc options ARE NOT available in combination with a heating jacket.
6.5 Pressure Ratings
Meter data plates are stamped with maximum pressure rating (at 20°C and max. operating
temperature) of connection, primary tube or secondary pressure containment (whichever is the
lower).
Pressure De-rating:
Stainless Steel tubes:
150 bar at 80°C or 2175 psi at 175°F
50 bar at 150°C or 725 psi at 300°F
Hastelloy C22 tubes:
150 bar at 150°C or 2175 psi at 300°F
(no de-rating required)
20 °C 50°C 100°C 150°C
30 bar 28.5 bar 26.1 bar 24 bar