A-9
Model 199 Differential Pressure Unit (DPU)
Section 3
Section 3—Installation/Operation
Unpacking
The 199 DPU should be inspected at time of unpacking to detect any damage
that may have occurred during shipment.
IMPORTANT: The instrument was checked for accuracy at the factory. Do not change
any of the settings during examination or accuracy will be affected.
IMPORTANT: For application in critical media, requiring special cleaning processes
and precautions, a polyethylene bag is used to protect the instrument
from contamination. This protective bag should be removed only under
conditions of controlled extreme cleanliness.
IMPORTANT: Do not locate the instrument near vents or bleed holes that discharge
corrosive vapors or gases.
Mounting
Flush or Panel Mounting
Attach the case of the instrument (switch or indicator) to the panel or wall.
Refer to the instrument's installation manual for mounting details.
Piping—Standard Practices
All Applications (Flow and Liquid Level)
1. Shorten the distance between the primary device and the DPU as much
as possible. Distances exceeding 100 feet are not recommended. For dis-
tances up to 50 feet, use 1/4-inch or 3/8-inch pipe or tubing. For runs of
50 to 100 feet, use 1/2-inch pipe or tubing. The recommended limitation
does not apply if an air purge or blow-back system is used.
2. Slope all piping at least one inch per linear foot to avoid liquid or gas
entrapment.
3. Provide 2 feet of non-insulated piping between the DPU and the primary
device for each 100°F (+37.8°C) in excess of +200°F (+93.3°C).
4. Assure that the temperature of the DPU never exceeds 180°F (+82°C).
When steam tracing is necessary, the steam pressure should not exceed
5 pounds per square inch and insulation should not be used. If pressure
must exceed 5 pounds per square inch, limit the length of tubing around
the DPU to two turns and do not insulate.
Содержание BARTON 289A
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