Spirax Sarco ELM, Инструкция по установке, эксплуатации и обслуживанию, Страница: 20 / 80

IM-P309-02 MI Issue 2 20
8.3.4 Torques for studs and nuts
Electromagnetic flowmeters must be installed in the pipe system with special care due to the
fact that the flow pipe lining is made of PTFE which is malleable under pressure.
If the flange nuts are tightened too much, the sealing surface will deform. If the seals are
supposed to function properly, the correct torque is highly important.
Tighten the nuts crosswise, so that the process connections are tight. When tightening the
nuts for the first time, approximately 50% of the required torque should be reached, and for
the second time, the torque should be 80%. The required torque should reach 100% when
the nuts are tightened for the third time. For higher torques it is advisable to use protectors.
The following tables state the maximum torques:
Nominal size
(mm)
DIN Pressure
rating (bar)
Studs Maximum torques
(Nm)
DN25 PN40 4 x M12 25
DN32-40 PN40 4 x M16 45
DN50 PN40 4 x M16 65
DN65 PN16 4 x M16 85
DN80 PN16 8 x M16 55
DN100 PN16 8 x M16 55
DN150 PN16 8 x M20 100
DN200 PN16 12 x M20 95
Nominal size
(inch)
ASME Pressure
rating (lbs)
Studs Maximum torques
(Nm)
1" Class 300 4 x ⅝" 15
1 ¼"-1 ½" Class 300 4 x ¾" 35
2" Class 300 8 x ⅝" 25
2 ½" Class 150 4 x ⅝" 85
3" Class 150 4 x ⅝" 80
4" Class 150 8 x ⅝" 55
6" Class 150 8 x ¾" 105
8" Class 150 8 x ¾" 145