  THERMOCOUPLES FOR IN-STREAM PLASTIC MELT - C8A Series Bookmark this page!
Oftentimes it is desirable
to measure the true temperature of the flowing plastic in an extruder
nozzle. This provides valuable information regarding the mixing characteristics
of the plastic melt, the efficiency of the screw, an accurate temperature
profile of the plastic melt, the magnitude and shape of the temperature
profile across the stream, etc. NANMAC has designed two special Thermocouples
with low millisecond response times to measure the in-stream temperatures.
Both styles, one with a fixed immersion tip length and one with an adjustable
immersion tip length, are designed to minimize conduction errors. Both
units are available in
Thermocouple calibration types J, K. E, and T.
For
additional information on these as well as other high-performance plastics
thermocouples, refer to the article Selecting
the Right Thermocouples 
in the resource center.
FIXED IMMERSION LENGTH
The fixed length
immersion tip unit includes a gland nut and a thermowell.
The sensing tip of the thermowell has a wedge shaped tip to
minimize the shear effects. Therefore the leading edge of
the wedge must face up-stream, into the oncoming plastic.
A peen mark is machined onto the thermocouple near the connector
to indicate orientation for this unidirectional installation.
Also, wrench flats are provided to hold the Thermocouple in
place while tightening the gland nut. Maximum service temperature
and pressure rating of this unit is 750 degrees F and 20,000
PSI respectively.
Part
No. |
Description |
Diameter
"A" - inches |
Unit
Cost |
|
Fixed |
Fixed |
Fixed |
Adjustable |
|
|
| $385.00 |
| $385.00 |
| $385.00 |
| $470.00 |
|
|
ADJUSTABLE IMMERSION LENGTH
The adjustable immersion
tip unit is similar to the fixed unit, except the immersion
length is adjustable to any depth from flush on inner wall,
to one inch immersion. Also, the sensing tip is omni-directional
instead of unidirectional and spherically shaped to minimize
shear effects. On the connector end of this unit there are circular
minimize
shear effects. On the connector end of this unit there are circular
grooves machined into the shaft at 1/10 inch intervals. These
grooves are for indicating the insertion depth of the sensing
tip while the unit is installed. After installation and before
plastic hardens/freezes you simply screw the thermowell in or
out to the desired insertion depth. An internal 0-ring provides
a leak tight seal to 10,000 PSI at melt temperatures of up to
600 degrees F. This unit can be set for insertion depths from
flush on the inner wall to one inch insertion. Adjustment needs
to be done either while plastic is in its liquid state, or upon
initial installation when there is no plastic present. Otherwise
there is risk of breaking the thermocouple due to frozen melt
media.
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