K-Patents PR-33-S User Manual
Page 21
3 Inline refractometer sensor
17
© Copyright K-Patents 2015. All rights reserved.
3.1.3 Check list for pipe mounting
Most K-Patents inline refractometer models are mounted in a pipe. K-Patents recom-
mends a minimum flow velocity of 1.5 m/s (5 ft/s). The diameter and form of the pipe
and the process temperature all 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 stays clean better.
2. If the refractometer is used in a feed-back control loop, make the time lag short. E.g.
when a dilution valve is controlled, 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. That minimizes the risk of coating, because higher tempera-
ture 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 should be conveniently accessible for service.