Precautions Regarding Installation - YOKOGAWA DY025 User Manual

2.3 Precautions Regarding In-
stallation
WARNING
In case of high process temperature, care should be
taken not to burn yourself because the surface of
body and case reach a high temperature.
(1) Gas or Steam Measuring Precautions
• Piping to Prevent Standing Liquid
Mount digitalYEWFLO in a vertical pipeline to avoid
liquid traps. When digitalYEWFLO is installed horizon-
tally, raise that part of the pipeline in which the
digitalYEWFLO is installed.
(Good)
Flow
Figure 2.2
(2) Liquid Measurement Precautions
To insure accurate measurement, the digitalYEWFLO
must always have a full pipe.
• Piping Requirements for Proper Operation
Allow the flow to flow against gravity. When the flow is
moving with gravity, lift the down-stream pipe length
above the digitalYEWFLO installation level to maintain
full pipeline.
Flow
(No Good)
(Good)
Flow
Figure 2.3
(Good)
Flow
(No Good)
Flow
F020301.EPS
(No Good)
Flow
h h>0
(Good)
Flow
F020302.EPS
• Piping for Avoiding Bubbles
Flows containing both gas and liquid cause problems.
Avoid gas bubbles in a liquid flow. Piping should be
carried out to avoid bubble generation.
Install the valve on the downstream side of the flowme-
ter because pressure drop across the control valve may
cause gas to come out of the solution.
(Good)
Figure 2.4
(3) Multi-Phase Flow
digitalYEWFLO can measure gas, liquid and steam
when there is no change in state. However, accurate
measurement of mixed flows (e.g. gas and liquid) is not
possible.
h
h>0
Figure 2.5
2-4
2. INSTALLATION
(No Good)
Control
Value
Flow
(Good)
Flow
Flow
(No Good)
Mist flow
(No Good)
Liquid
Flow
Stratified flow
(No Good)
Gas Flow
Bubble flow
F020304.EPS
F020303.EPS
IM 01F06A00-01E