Device for removing moisture in resin in screw charging barrel

Abstract

A device for removing moisture in resin in a screw charging barrel is characterized in that a screw flight groove is formed in the outer diameter of a screw flight of a screw in a heating charging barrel, the screw flight groove starts from a screw compression section and extends to a screw groove starting section in the middle of the screw, and gas in a screw groove of the screw can enter the screw flight groove through a gap between the screw and the charging barrel; for resin with the forming temperature lower than 100 DEG C, the air exhaust connector arranged on the charging barrel can be connected with a vacuum generator, the air pressure in the charging barrel is reduced, the evaporation temperature of water is reduced, and the resin forming temperature is improved. The technical scheme is suitable for machines, such as extruders, injection molding machines and the like, in which moisture in resin needs to be removed in a screw charging barrel.

Description

Technical Field

[0001] The present invention relates to a device for removing moisture from resin in a screw barrel, specifically a technical solution and device which does not require drying equipment and utilizes a rotating screw in a heated barrel during resin processing to pre-refine the resin and simultaneously remove moisture from the resin, and can evaporate the moisture in the resin at a temperature below 100°C. Background Art

[0002] Resins have a certain degree of water absorption. Resins with strong water absorption, such as nylon, ABS, resin paraffin, etc., need to remove the absorbed water before processing and dyeing. There are two existing methods for removing water. One is to bake the resin in an oven for several hours before use or directly install the oven at the feed port of the processing machine and bake it for a certain period of time, and then bake while feeding. This method requires additional electric heating, which is time-consuming and power-consuming, and the water inside the solid particle resin is difficult to remove. Another method is to open a hole in the middle section of the barrel of the processing machine so that the water vapor in the pre-melted molten resin in the rotating screw groove in the heated barrel can be discharged from the barrel. However, the vent hole on the barrel should not be located in the compression section of the screw, so it is difficult to exhaust the molten resin entering the compression section. This method can still be used on extruders where the screw does not move axially. For injection molding machines where the screw moves axially, the molten resin in the screw groove is easy to overflow from the barrel vent hole. To avoid overflow from the barrel vent hole, the vent hole on the barrel needs to be located away from the compression section of the screw. Both the barrel and the screw must be lengthened. Due to the increase in the aspect ratio of the screw, some resins that are easily decomposed by heat, such as polycarbonate, cannot be processed. In addition, it is difficult to exhaust the molten resin in the front section of the vent hole, and the water removal effect is not good. The above two methods are difficult to remove moisture from resins that require processing below 100°C. Summary of the invention

[0003] The purpose of the present invention is to make up for the above-mentioned shortcomings and to disclose to the society a technical solution and device that does not require an oven equipment, does not require a hole to be opened in the middle section of the barrel of a processing machine, and does not require an extended barrel and screw. By providing a screw rib groove on the screw rib of the screw in the heating barrel, the screw rib groove extends toward the screw head to the screw compression section, and water vapor can be discharged through the screw rib groove, thereby effectively removing moisture from the resin in the screw barrel. For resins with an injection temperature lower than 100°C, the exhaust interface provided on the barrel can be connected to a vacuum generator to reduce the air pressure in the barrel and the evaporation temperature of water. The evaporation temperature of moisture in the resin in the barrel is determined by the degree of vacuum.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] A device for removing moisture from resin in a screw barrel, wherein a nozzle is fixed to one end of the barrel by a thread, the other end of the barrel is over-fitted with a barrel seat and is fixed by a barrel nut, a soft seal is used to seal the gap between the screw and the barrel, a flat key limits the rotation of the barrel, the screw and the barrel are clearance-fitted, the screw and the inner hole of the injection cylinder piston rod are over-fitted and connected by a flat key, and then fixed by pressing, the injection cylinder and the barrel seat are fixed by screws, a rotating power element is fixed to the rear end cover of the injection cylinder, the output shaft of the rotating power element is connected to the injection cylinder piston rod by a spline, and the rotating power element can be The injection cylinder piston rod is driven to rotate, and the injection cylinder piston rod can drive the screw to rotate and reciprocate. The pressure-resistant hopper is fixed to the drop port of the barrel seat with screws. The pressure-resistant hopper cover and the pressure-resistant hopper joint surface are sealed with a soft seal. The barrel seat and the slide rod are matched with each other in a clearance. The barrel seat can move horizontally on the slide rod. The slide rod and the slide rod seat are excessively matched. The slide rod and the slide rod seat are fixed by a pressure plate and screws. The slide rod seat is fixed to the frame. The outer diameter of the screw ridge that matches the barrel clearance is provided with a screw ridge groove. The screw ridge groove starts from the compression section of the screw and extends to the vicinity of the screw groove starting section in the middle of the screw. The gas in the screw groove can enter the screw groove through the gap between the screw and the barrel, and be discharged from the exhaust interface through the screw groove through the gap between the screw without the screw groove section and the barrel. For resins with higher requirements for processing water removal and processing temperature requirements below 100°C, the exhaust interface is connected to a vacuum generator, and a pressure-resistant hopper and a pressure-resistant hopper cover are used to reduce the air pressure in the barrel, so that water vapor evaporates below 100°C. For most resins that do not have particularly high requirements for processing water removal and processing temperature requirements above 100°C, the present invention provides screw grooves on the outer diameter of the screw ridge of the screw. The technical solution that the screw groove starts from the screw compression section and extends to the screw groove starting section in the middle of the screw can meet the requirement of removing moisture from the resin in the screw barrel, and a non-sealed hopper can be used. The exhaust interface can be connected or not connected to the vacuum generator. The present invention arranges the screw groove on the outer diameter of the screw rib of the screw, and the screw groove starts from the screw compression section and extends to the screw groove starting section in the middle of the screw. The technical solution is applied to extruders in which the screw does not make axial movement relative to the barrel and injection molding machines in which the screw makes axial movement relative to the barrel, and also has the effect of removing moisture from the resin in the screw barrel. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic cross-sectional view from a horizontal perspective.

Claims

1. A device for removing moisture from resin in a screw barrel, wherein a nozzle (1) is fixed to one end of a barrel (2) by a thread, the other end of the barrel (2) is overfitted with a barrel seat (8) and is fixed by a barrel nut (9), a gap between the screw (3) and the barrel (2) is sealed by a soft seal (10), a flat key (17) limits the rotation of the barrel (2), the screw (3) and the barrel (2) are clearance-fitted, the screw (3) and the inner hole of the injection cylinder piston rod (11) are overfitted and connected by a flat key and are fixed by a pressure, the injection cylinder (12) and the barrel seat (8) are fixed by screws, a rotating power element (13) is fixed to the rear end cover of the injection cylinder (12), and the rotating power element (13) is output The output shaft and the injection cylinder piston rod (11) are connected by splines, the rotating power element (13) can drive the injection cylinder piston rod (11) to rotate, and the injection cylinder piston rod (11) can drive the screw (3) to rotate and reciprocate, the pressure hopper (5) is fixed to the blanking port of the barrel seat (8) by screws, the pressure hopper cover (6) and the pressure hopper (5) joint surface are sealed by a soft seal (7), the barrel seat (8) and the slide rod (15) are clearance-matched, the barrel seat (8) can move horizontally on the slide rod (15), the slide rod (15) and the slide rod seat (14) are over-matched, the slide rod (15) and the slide rod seat (14) are fixed by a pressure plate and screws, and the slide rod seat (14) is fixed to the frame, characterized in that : The screw groove (4) is arranged on the outer diameter of the screw rib of the screw (3) which is in clearance with the barrel (2). The screw groove (4) starts from the compression section of the screw (3) and extends to the vicinity of the screw groove starting section in the middle of the screw (3). The gas in the screw groove of the screw (3) can enter the screw groove (4) through the gap between the screw (3) and the barrel (2), and is discharged from the exhaust interface (16) through the screw groove (4) through the gap between the screw (3) without the screw groove section and the barrel (2). For resins with higher requirements for processing water removal and processing temperature requirements below 100°C, the exhaust interface (16) is connected to a vacuum generator, and a pressure-resistant hopper (5) and a pressure-resistant hopper cover (6) are used to reduce the air pressure in the barrel so that water vapor evaporates at a temperature below 100°C. For resins with low requirements for processing water removal, the exhaust interface (16) is connected to a vacuum generator, and a pressure-resistant hopper (5) and a pressure-resistant hopper cover (6) are used to reduce the air pressure in the barrel so that water vapor evaporates at a temperature below 100°C. Most resins have particularly high processing temperatures higher than 100°C. The present invention provides a screw groove (4) on the outer diameter of the screw rib of the screw (3), and the screw groove (4) starts from the compression section of the screw (3) and extends to the vicinity of the screw groove starting section in the middle of the screw (3). The technical solution can meet the requirement of removing moisture from the resin in the screw barrel. The present invention provides a screw groove (4) on the outer diameter of the screw rib of the screw (3), and the screw groove (4) starts from the compression section of the screw (3) and extends to the vicinity of the screw groove starting section in the middle of the screw (3). The technical solution is applied to an extruder in which the screw (3) does not make axial movement relative to the barrel (2) and an injection molding machine in which the screw (3) makes axial movement relative to the barrel (2), and also has the effect of removing moisture from the resin in the screw barrel.

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