2.4.3 Insulated Pipeline
For the magnetic flowmeter mounted in a liquid insulated pipeline (such as ceramic lined iron pipe, or
cast pipe with internal bitumastic coating), perform the grounding procedure outlined below. Refer to
Figures 2-10 and 2-11 to supplement this discussion.
1. Grounding rings are mounted between the meter, and the upstream and downstream pipe flanges.
These metal grounding rings are available in various corrosion resistant materials and should be
selected to be compatible with the process liquid. When installed, these rings are centered by the
flange bolts and therefore must be selected according to the flange rating. If grounding rings were not
specified when the meter was ordered, refer to Section 7.0 Tables 7-1 and 7-2 for ordering informa-
tion. Refer to Figure 2-12 for the outline dimensions of the grounding rings.
2. When installing the meter in the pipeline, place a grounding ring at both the inlet and outlet
connections of the magnetic flowmeter. Provide gasketing between the face of the meter (see Figure
2-11) and the grounding ring and between the grounding ring and the adjacent pipe flange; i.e., four
gaskets required. (Note that the gasket at the meter face must fit inside the end ring.) Position the
grounding rings in the pipeline so that the meter grounding straps (2) attached to the meter ground
post will easily reach the ground strap connection bolt on the respective grounding ring.
3. The user must supply two bonding wires which will connect the flanges adjacent to the meter to the
meter grounding rings. These should be made with ring lugs and #12 AWG, or heavier, copper wire.
They should be secured, along with the free end of each stainless steel bonding strap from the meter,
to the upstream and downstream grounding rings, using 1/4" hex head bolts and external tooth
lockwashers (supplied with the grounding rings when the rings are supplied by ).
4. The flanges adjacent to the meter must be drilled and tapped for 1/4" threads. A bright metal
surface around the area of the tapped hole must be obtained using a file or emery cloth. The bonding
wires from the grounding rings are to be attached to the flanges with 1/4" bolts and external tooth
lockwashers.
5. The user must supply a sufficient length of wire for connecting the meter grounding post (ring lug
supplied) to a good electrical ground. (Number 12 AWG, or heavier, copper wire may be used for this
grounding wire.)
2.4.4 Non-Conductive Pipeline
The magnetic flowmeter may not be installed in a non-conductive pipeline such as plastic or
concrete. For proper operation of the meter, install pipe with a non-conductive exterior on either side
of the meter. The length of non-conductive pipe as measured from the centerline of the meter must
be equal to at least five times the diameter of the pipe. Refer to Figure 2-5.
Grounding procedures outlined in this section must be adhered to for satisfactory meter operation.
10D1477 MAGNETIC FLOWMETER INSTRUCTION MANUAL
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Summary of Contents for 10D1477
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