Barton 227C, Руководство по установке

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5
Calibration Check
Normally all that is required to adjust the indicator to the factory-set calibration
tolerances is to perform the following calibration check.
1. Connect the instrument to a standard pressure source as shown in Test/
Calibration Equipment, page 4.
2. Remove the plug from the low pressure housing.
3. Apply approximately 150% of the differential pressure range to the high
pressure housings. Release pressure. Repeat 3 or 4 times.
4. Apply 0%, 50% and 100% of full scale pressure. If indication is within the
specified limits, no further adjustments are necessary. If the zero indication
is incorrect, remove the bezel and glass assembly (per Accessing Indicator
Mechanism procedure on page 4) and adjust the pointer by turning the
pointer by the hub.
5. Replace the bezel and glass assembly . The bezel gasket
(0277.0026C) must be installed as shown below:
The two snubbers (0266.0028C) on the scaleplate should not be com-
pressed against the glass cover and the pointer should not touch the glass.
Notice
Ensure correct bezel gasket orientation before placing instrument
back in service. Incorrect bezel gasket orientation will cause the
instrument indicator to jam, resulting in inaccurate readings.
Complete Calibration
A complete calibration of the instrument is required whenever the DPU assem-
bly is replaced.
1.
Connect the instrument to a standard pressure source as shown in the Test/
Calibration Equipment illustration on page 4.
2. Attach linkage between drive arm and movement. (The illustration on the
right shows alignment at 50% differential pressure.)
Inspect parts for straightness and pivot-fit without binding.
3. Set the pointer at zero on the scale by slipping the pointer on the hub.
Hold the pointer tip and turn the hub with a wrench.
4. Apply 100% differential pressure. If pointer exceeds 100% on the scale,
lengthen the range arm. Remove pressure.