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Increasing the initial moisture content and its mixture temperature resulted
in increasing the flow rate by reducing the viscosity of the melt in the extrusion
process before matrix zone. Product temperature distribution along the length of
the extruder is characterized by its sharp increase, since the compression zone
until before matrix area. The matrix is constant from - the segment of the small
residence time in it and the product outlet of the mold channel decreases rapidly
to 370.. . 380 0K due to explosive evaporation of water and release significant
amounts of energy.
And with an increase in pressure in the temperature zone before matrix
food mixture increases slightly. The initial moisture content of food protection
along the length of the extruder does not change (ie. E. Has a permanent
residence due to the tightness of the extruder working chamber and the absence
of degassing zones) to the extrudate to enter the atmospheric pressure zone,
where flashed around 10. . 20 % water.
The character of temperature and pressure changes over time and the length
of the working area allowed us to estimate the effect of these parameters on the
course of the extrusion process, to justify its rational modes and get the
performance of a single-screw extruder at optimum specific energy consumption
for production of sticks.
With the intensification of a mechanical action on the product (i - »max, Q -
> max) melt formation occurs, and consequently, a decrease in its viscosity.
Stronger observed effect of the counter-melt material, which causes a decrease
at some point developed pressure.
There is a directly proportional linear relationship, with an increase in
angular velocity of rotation of the screw extruder performance increases, and
more intense with increasing initial moisture content and temperature of the
product in before matrix zone, due to less resistance movement of the material in
the screw channel of the screw. The increase of moisture content in the raw
material with 12 to 15 % resulted in a reduction of the specific consumption of
electricity - a decrease of the melt viscosity, the more intense with increasing
temperature before the matrix.
In the same lift angle screw helix can be achieved similar performance
(except the maximum) at two different depths of cut. To promote the product in
the feed zone of the extruder the optimum angle is 13 ° 38 '. At small cutting
depths at the outlet end of the metering zone of the screw occurs in the same
number of turns less back flow, which provides a more efficient flow of
material, but large energy transitions (increasing shear inversely cutting depth)
and the product is processed at a higher temperature.
Warming up the product in the chamber is carried out with a stronger
increase in the angular velocity of the screw, the temperature change is much
harder from - the increase in the degree of compression pressure and growth in
this sector.
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