Intek 100 - Manual (Page 11)

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MODEL100 REV D.wpd
4. Flow straightener — TU sensors of 3 '
16
" or larger size may require a flow straightener in
certain low viscosity liquids. The straightener is used to keep the flow regime out of the
transition region (from laminar to turbulent). The straightener is shipped installed in the flow
tube. It may be removed for cleaning and must be correctly reinserted for accurate operation
of the meter. It always installs from the inlet side of the sensor, and one end of the
straightener has one or two hooks on the end which should end up nestled in the notch(es) at
the inlet end of the flow tube. It should not take too much force to remove or install the
straightener. Take care not to bend it while it is out of the sensor.
3.4 OUTPUT CURVE
Figure 2 is the final nonlinear output curve for your unit. The instrument has been calibrated over the
actual flow rate range indicated on the ordinate (Y axis).
3.5 TRANSDUCER & ELECTRONICS FUNCTIONAL TESTS
A test of the Rheotherm instrument functional operation can be performed in three phases as outlined
below:
1. Transducer continuity check, Figure A p. 11.
2. Transducer isolation check, Figure B, p.11.
3. Electronic circuit board check, Figure C, p.11.
1. The transducer continuity check is performed as follows (see Figure A, p. 11):
A. Disconnect the transducer cable from the electronics.
B. Make resistance measurements between the cable pairs as shown in Figure A. The
readings should be as indicated; if not, consult factory for repair.
2. The transducer isolation check is performed as follows (see Figure B, p. 11):
A. Disconnect the transducer cable from the electronics.
B. Make the circuit connections illustrated in Figure B.
C. Probe all the conductors and note the voltage with respect to the shield. All readings
should be less than 0.5 Vdc. The yellow (Y) wire should also be isolated from the blue
(Blu) and the green (G) wires. Connect the "low" test lead to Y and probe the Blu and
G terminals with the "high" lead. Again, the meter should read less than 0.5 Vdc in both
cases; if not, consult factory for service. Also, check for isolation between the blue (Blu)
and green (G) wires.
3. The sensor input to flow output of the electrical circuit is checked as follows (see Figure C, p.
11):
A. Construct the dummy transducer as illustrated in Figure C.
B. Turn off power to the unit.
C. Disconnect the transducer cable from the instrument.
D. Connect the dummy transducer to the instrument input.