VAF instruments OILCON MARK 6M, Technical Manual

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6.3.8 dP/I transmitter
The electronic differential pressure transmitter is a two- wire transmitter which converts the
differential pressure developed by the flow sensor into a 4–20mA signal.
Select a location for the transmitter that is close to the orifice plate, not exceeding 16m and where
the ambient temperature will not exceed 90°C nor be less than -40°C. The location should be as
free from vibration as possible.
The transmitter must be mounted so that the measuring element is vertical. A mounting bracket and
U-bolt is supplied to mount the instrument on and is suitable for either pipe or surface mounting. For
pipe mounting, the bracket accepts from 30 mm up to 60 mm diameter pipe and can be positioned
on a horizontal or vertical pipe.
The differential pressure sensing lines from the flow sensor are coupled to the transmitter’s 3-way
manifold using ¼” NPT/10 mm couplings which are supplied.
The 3-way manifold contains isolating valves and an equalizing valve.
The pressure sensing lines must be routed with a minimum gradient of 1:10 fall after an initial fall
from the pressure tapping points of 300 mm. The lines should be adequately clipped. Two isolating
valves are supplied; one end threaded ¼” BSP for connection to the pipe.
The dP/I transmitters are certified as
II 1 G Ex ia IIC T4 or T5.
EXPLANATION OF EQUIPEMENT MARKINGS: “Ex” Equipment in compliance with
European standards for potentially explosive atmospheres.
“ia” Equipment in compliance with specific building rules for intrinsically safe
equipment.
“C”
Equipment for use with gas of the subdivision C.
“T4” Equipment whose surface temperature does not exceed 135°C when used in an
ambient temperature less than 80°C.
The equipment is suitable for areas classified as:

Zone 0 (an area in which an explosive atmosphere is present continuously or during long
periods);

Zone 1 (an area in which an explosive atmosphere is likely to occur in normal operating
conditions);

Zone 2 (an area where an explosive atmosphere is not likely to occur in normal operation).