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PRINCIPAL OF OPERATION:
The Turbine Flow Meter is a rugged, versatile instrument
capable of handling a wide variety of liquids including many types of
Slurries and Suspensions. The Flow Meter contains a rotor secured to a
tungsten carbide shaft. The shaft is supported at each end in tungsten
carbide bearings. The rotor is made of a magnetic material, while the
Flow Meter body is non-magnetic. A magnetic pickup consisting of a magnet
and coil is mounted externally in the body in the same plane as the rotor.
Fluid moving through the Flow Meter causes the rotor to rotate at a speed
proportional to the fluid velocity. The rotor blades cutting the magnetic
field in the vicinity of the magnetic pickup generate a frequency signal
proportional to the fluid velocity. This signal is used to represent flow
rate and can be accumulated to totalize the volume of liquid passing through
the Flow Meter. Each Plow Meter should be calibrated to insure accuracy
over the entire recommended flow range. Flow Meters should be finished
with a calibration factor representing the number of pulses per gallon
produced. This information should also be supplied with the pre-calibrated
rotor and vane kits that should be available for field replacement, if
needed. Generally meter accuracy is available in 1.0% or 0.5% accuracy
in the fill range of the meter. If meter is operated in the upper 60%
of its range, a better accuracy can be obtained which will improve the
1.0% accuracy to 0.5% and the 0.5% accuracy to 0.25%.
INSTALLATION:
The Turbine Flow Meter may be installed either vertically
or horizontally. The direction of flow should correspond to the flow direction
arrow that appears on the outside of the housing, since this is the direction
that the meter was calibrated. NOTE: Turbine meters, due to their design,
may flow fluid in either direction; but, are generally calibrated in one
direction unless specified. A minimum straight section of pipe with a
length of (5 or 10) diameters of the same size as the Flow Meter end connection
is required both upstream and downstream of the meter. NOTE:
Some manufacturers guarantee accuracy with 5 diameters
and others prefer the 10 diameters. API recommends the 10 diameters.
The following precautions should be observed during the
installation and operation of the Flow Meter:
- Clean all upstream lines before installing the Flow
Meter.
- Do not slug the Flow Meter with fluid. Initial filling
of line with fluid should be done with care.
- Do not exceed maximum recommended flow rate through
the Flow Meter.
- Avoid hammer blows or other sharp impacts on the Flow
Meter; it may break the shaft, and with this in mind, the use of hammer
unions on threaded meters is not recommended. Wrench type 0-ring seal
unions are preferred,
- The magnetic pickup should be installed as per attached
Figure 2. If vibration is present, the lock nut supplied with the magnetic
pickup should be tightened. A 3/4" 12 point thin-walled deep socket
wrench is required for this.
Maintenance:
Figure 1. illustrates a typical Flow Meter. The following
instructions are applicable to all meter sizes except as noted.
The Flow Meters may be disassembled for inspection, cleaning
or repair in the following manner:
- Screw the magnetic pickup out of the housing to avoid
breaking during handling of the meter.
- Remove the retainer ring from one end of the housing.
- Slide the vane from the housing. (If the vane should
be stuck, insert a brass rod through the opposite vane and through the
rotor and drive the vane out be tapping on alternate blades of the vane.
- In 3" and smaller size meters, the rotor may now be
removed. In 4", 6" and 3" meters, it is necessary to remove the inner
retainer ring before the rotor can be taken out. The rotor should be
bandied with care to prevent damage to the rotor shaft.
- Remove the retainer ring from the other end of the
housing.
- Remove the other vane.
- Do not attempt to remove the bearings and thrust balls
from the vanes,
- Clean all parts with a suitable solvent for the material
that has been pumped through the meter. A cotton swab is very useful
for cleaning the inside diameter of the bearings.
The meter is assembled in the following manner:
- Lubricate the bearing with the few drops of light machine
oil or 5 centistoke silicone oil. During operation, the meter is lubricated
by the fluid that is being pumped. The purpose of this initial lubrication
is to enable the meter to be tested after assembly without running the
bearings dry.
- Before assembling, note that an arrow is cast or engraved
on each part. These arrows indicate the direction of flow The meter
must be assembled so that all arrowheads point the same way and the
direction of flow must coincide with the direction of flow indicated
on the housing.
- In all sizes, observe that one of the blades on each
vane has a mark or notch on it and that the retainer pins, welds or
notches are provided in each end of the housing. The marked or notched
blade must be inserted between these retainer pins, weld spots or notches,
The meters are calibrated in this position, and should be reassembled
in this position for the greatest accuracy. (See Figure
- Insert one of the vane assemblies in the housing bore
being careful that the direction arrow is correctly oriented. The vane
should fit snugly but should not require excessive force to install.
- Install the rotor and rotor shaft assembly being careful
to properly orient & the direction arrow on the rotor. Care should be
taken to avoid chipping the rotor shaft. Tungsten carbide is very brittle.
- Insert the other vane assembly. If this vane does not
fall into position when placed in the housing, rotate the rotor to align
the bearing and the rotor shaft. Do not aflempt to drive the vane in,
as this will result in a broken rotor shaft.
- Check the meter by blowing air through it. The rotor
should turn freely and come to a smooth stop. If the rotor will not
turn or stops abruptly, the meter should be disassembled and checked.
- Screw the magnetic pickup into the housing according
to the procedure indicated by (Figure 2.). Tighten finger tight and
set lock nut. Do not tighten with pliers or wrench.
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