Screw extruder barrel and temperature control method thereof

Abstract

The invention provides a screw extruder barrel and a temperature control method thereof. The barrel has a double-layer two-channel temperature control structure; on two different radial layers of the cross section of the barrel, a plurality of heat conducting medium runners are formed on two layers; a heating medium or a cooling medium can be introduced into the runner; the outer-layer runners are formed along the peripheral direction of the barrel, and the inner-layer runners are formed along the axial direction of the barrel; and the runners of the two layers are connected in parallel. Two temperature sensors are arranged inside and outside to respectively measure the nearby temperature of the inner surface of the barrel and the temperature of the outer layer of the barrel, the barrel temperature is controlled by a logic control program, and the local temperature difference of the inside and outside of the barrel and the alternate cold and hot local temperature difference can be reduced, so the temperature control of the whole barrel is uniform, overhigh stress is not generated locally, the contact heat transfer area between the heat conducting medium and the barrel is effectively increased, the heat exchange efficiency is improved, the sensitivity of the barrel temperature control system is improved and the energy consumption is reduced. The screw extruder barrel and the temperature control method are particularly suitable for large and medium-size double-screw extrusion granulators.

Description

Technical field: [0001] The invention relates to a barrel of a screw extruder, in particular to a barrel with a temperature control channel structure, in particular to the improvement of the heating / cooling channel structure of the barrel and a method for controlling the barrel temperature. It is suitable for large-scale screw extrusion granulation unit. Background technique: [0002] At present, the heating / cooling methods commonly used in the barrel of screw extruder mainly include: 1. External electric heater heating + water cooling method. The barrel has a cooling channel and uses water as the cooling medium. Due to the influence of water vaporization, Both the temperature control range and the temperature control accuracy are restricted. 2. External electric heater heating + steam cooling method. This method uses high-pressure steam as the cooling medium to overcome the problem of water vaporization, but it must be equipped with a high-pressure steam supply station. 3. Ext...

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Problems solved by technology

[0002] At present, the heating / cooling methods commonly used in screw extruder barrels mainly include: 1. External electric heater heating + water cooling method. In this method, the barrel is provided with a cooling channel, and water is used as the cooling medium. Due to the influence of water vaporization, Temperature control range and temperature control accuracy are limited

2. External electric heater heating + steam cooling method, this method uses high-pressure steam as the cooling medium, which overcomes the problem of water vaporization, but it must be equipped with a high-pressure steam supply station

However, due to the external electric heating method, the temperature difference between the inside and outside of the extruder barrel is large, especially for large extruder barrels, it is easy to cause uneven temperature distribution of the barrel, which will cause deformation of the barrel and affect the use of the unit. Therefore, this method There are only examples of application in large granulation units with screw diameters less than 320mm

[0003] Chinese patent (200810011909.1) discloses a dual-channel barrel with the same layer arrangement, such as figure 1 , figure 2 As shown, on the same radial level of the cross-section of the machine barrel, two sets of heat-conducting medium axial channels are arranged alternately at intervals, which are heating medium flow channels and cooling medium flow channels respectively. Heating and cooling are carried out in the machine barrel to avoid The temperature difference between inside and outside is too large, but the dual-channel barrel arranged on the same layer still has the following defects for the temperature control of the barrel of a large extruder: A. Due to the alternate arrangement of cold and hot runners on the same layer, the local temperature difference at the alternation is too high Large, especially at the welded part of the end face of the barrel, it is easy to produce large thermal stress deformation, which leads to welding cracking; B, the same layer arrangement, limited by the space layout, it is difficult to realize the parallel connection of the channels, resulting in the gap between the heat transfer medium and the barrel The contact heat transfer area is small, and the temperature control sensitivity is low; C. The temperature sensor installed on the barrel can only measure the surface temperature near the inner flow channel of the barrel, and the temperature of the outer layer of the barrel cannot be effectively controlled, resulting in energy waste

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