Liquid Temperature; Other Liquid Variables; Metering Characteristics; Model Number Breakdown - ABB MINI-MAG 10D1475 Instruction Manual

10D1475 MINI-MAG MAGNETIC FLOWMETER INSTRUCTION BULLETIN
Low conductivity fluids require special consideration when applying magnetic flowmeters. Bailey-Fis-
cher & Porter Applications Engineers will offer any assistance required for individual applications.

1.2.2.1.2 Liquid Temperature

Most liquids exhibit a positive temperature coefficient of conductivity. It is possible for certain
marginal liquids to become sufficiently non-conductive at lower temperatures so as to hamper
accurate metering. However, the same liquid at higher or normal environmental temperatures may be
metered with optimum results. The possibility of an adverse temperature conductivity characteristic
should be investigated before attempting to meter such a liquid. Process or ambient temperatures are
also limited by the meter materials specification.
Other normal effects of temperature, such as influence upon liquid viscosity and density, the size of
the metering area, and the flux density of the magnetic field, have negligible or no effect upon
metering accuracy.

1.2.2.1.3 Other Liquid Variables

Other liquid variables such as viscosity, density and liquid pressure have no direct influence on
metering accuracy. Liquid density has no effect on volumetric flow rate since only the area of the
meter pipe and liquid velocity are required to determine the rate of flow. Viscosity and metering
pressure are restricted to physical limitations alone, such as the leakage pressure of the meter pipe
flange connections.

1.2.2.2 Metering Characteristics

The metering pipe must be completely filled at all times for accurate results. If there is possibility of
operation with a partially filled horizontal pipeline, it is recommended that the Magnetic Flowmeter be
installed in a vertical section of that pipeline such that liquid flow moves upward. A vertical installation
also offers the advantage of an even distribution of liner wear in the event that solid abrasives are
being carried along in the liquid stream.
The Bailey-Fischer & Porter Magnetic Flowmeter will measure the total amount of material passing in
the liquid stream. The meter will not, for instance, differentiate between the amount of liquid and the
amount of entrained gases. Also, in the case of a slurry, it will not differentiate the amount of liquid
from solids. If the liquid to mixant ratio is of importance to process control, then separate measure-
ments of the concentration of the desired medium must be made and appropriate correction factors
must be applied to the Magnetic Flowmeter output.
In applications involving variable quantities of uniformly dispersed, non-conductive mixing agents, it
must be ascertained that the higher concentrations of mixant will not drive the average conductivity
of the liquid mixture below the minimum conductivity level for the given installation.

1.3 Model Number Breakdown

Refer to the Bailey-Fischer & Porter data sheet or the data tag on the equipment for the model
number of the instrument furnished. The details of a specific number are shown on the following two
pages.
INTRODUCTION

TABLE 1-1. ELECTRODE DIAMETERS

Meter Size
inch mm
⁄
1 3
10
⁄
5 4
32
⁄
1 6
4
⁄
3
10
8
⁄ ⁄
1 - 1 1
15 - 40
2 2
2 - 4 50 - 100
Electrode Diameter
inch cm
0.048 0.122
0.048 0.122
0.048 0.122
0.048 0.122
0.250 0.635
0.312 0.792
1-5