Pipe Mounting Checklist; Checklist For Mounting In Tank, Vessel Or Large Pipe - Vaisala PR-23 Series User Manual

PR-23 Series User Guide
3.3 Pipe mounting checklist
Most in-line refractometer models are mounted in a pipe. The recommended minimum flow
velocity is 1.5 m/s (5 ft/s). The diameter and form of the pipe and the process temperature
affect the measurement and need to be taken into account.
1. If the process pipe diameter varies, select the position with the smallest diameter (and
accordingly highest velocity). Then the prism keeps better clean.
2. If the refractometer is used in a feed-back control loop, make the time lag short. When
a dilution valve is controlled, for example, mount the refractometer close to the dilution
point. However, make sure complete mixing has occurred at mounting location.
3. If the temperature varies along the process pipe, select the position with the highest
process temperature. Then the risk of prism coating is minimized, because higher
temperature means higher solubility and also lower viscosity.
4. Often the position with the highest process pressure (= after pump + before valve) has
favorable flow conditions without sedimentation or air trapping risks.
5. The sensor is accessible for service.
3.4 Checklist for mounting in tank, vessel
or large pipe
A probe sensor PR-23-AP or PR-23-GP can be inserted with a flange or clamp into tanks and
vessels which either do not have a scraper or where the mixer does not touch the vessel
wall. A probe sensor can also be flush mounted in a cooker where the scraper touches the
wall.
1. The inserted probe sensor is mounted close to a stirrer to ensure representative sample
of the process liquid and to keep the prism clean.
2. The sensor is accessible for service.
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IM-EN-PR23-E