2 mounting the sensor – K-Patents PR-03 User Manual
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PR-03 instruction manual
a: optical image
b: detector window and the photocells
c: pulse train from detector
TIME
V
Figure 2.2
Image detector system
Note:
In the Probe refractometer PR-03-P the image is inverted by the optics. That is, the shadow comes
in from the left. The image is inverted back to normal (as in Figure 2.2) by the indicating transmitter before
any further processing.
2.2 Mounting the sensor
The sensor mounting location should be chosen with care to ensure that you get reliable readings from
your process. Some basic rules, described in this section, apply to all sensor models. The model specific
instructions can be found in Chapter 8.
2.2.1 Choosing sensor mounting location
A K-Patents in-line refractometer sensor can be located either indoors or outdoors in most climates. How-
ever, if the sensor is located outdoors, some basic protection against direct exposure to sunlight and rain
should be provided. Special care should be taken if the pipe wall is translucent (e.g. of fiberglass), because
light from outside reaching the prism will disturb the measurement.
The mounting location needs to be such that sediments or gas bubbles cannot accumulate by the sensor.
Good flow velocity is essential in keeping the prism clean.
Always check that the sensor head is kept cool enough, the sensor head should not be too hot to keep a hand
on. The red sensor cover should not be exposed to high temperature radiation. Normally, draft and natural
convection provide sufficient air cooling if the air gets to flow freely around the sensor head.
Additional cooling is necessary when the ambient temperature is higher than 45
◦
C (113
◦
F) or when the
process temperature is above 110
◦
C (230
◦
F) and the ambient temperature is above 35
◦
C (95
◦
F). The air-
cooling is improved by blowing pressurized air against the red sensor cover. The pressurized air can be
supplied by the ventilation system. If no air is available it is also possible to wind a copper coil for cooling
water around the sensor head cover.