KROHNE UFM 3030 EEx EN - Manual (Page 26)

26 UFM 3030
5 Service and maintenance
5.1 Introduction
Contact your nearest local KROHNE representative for ordering information of the UFC 030…-EEx
electronics units and/or fuses.
The UFM 3030 ultrasonic flowmeters are maintenance free with regard to the flow metering
properties. Within the scope of the periodical inspections, which are required for electrical apparatus
that is installed and used in a hazardous classified location, it is recommended to check the
flameproof converter housing on signs of corrosion and damages.
5.2 Replacement of electronics unit or power fuse(s)
The following instructions must always be carefully followed, if the flow converter
housing in which the UFC 030…-EEx is installed has to be opened respectively
closed again!
Before opening:
•
Make absolutely sure that there is no explosion hazard!
•
Gas-free certificate!
•
Make sure that all connecting cables are safely isolated from all external sources!
•
Allow the prescribed waiting time to elapse before opening the housing: 20 minutes for
temperature class T6 and 11 minutes for temperature class T5
When the instructions above are strictly followed, the cover (includes a glass window) of the
electronics compartment may be removed. First unscrew the recessed head screw of the
interlocking device by a hollow-head screw wrench size 3, until the cover can rotate freely. Unscrew
the cover with the special plastic wrench (black) that is supplied with the apparatus.
After opening:
•
The copper grounding strip at the back of the electronics unit must be securely screwed to the
housing (back-end of electronics compartment) by screw C (see figure below). The electronics
unit is screwed into the electronics compartment by two screws B. Before screws B and C can
be accessed, the display unit must be removed via screws A.
•
Before the cover is screwed back into the housing, the screw-thread must be clean and well-
greased with an acid and resin-free grease, e.g. silicone grease.
•
Screw the cover as tight as possible into the housing by hand, until it cannot be opened by hand
anymore. Screw the recessed head screw of the interlocking device tight.
Display unit (left) Electronics unit after removal of display unit (right).