Exhaust device for screw extruder

Abstract

The utility model discloses an exhaust device for a screw extruder, which comprises a body, the bottom surface of the body is provided with a first curved surface matched with the peripheral side of a screw, and the first curved surface is provided with a through hole penetrating through the top surface of the body; the pushing block is connected to the through hole in a sliding mode, the outer circumferential side face of the pushing block is attached to the inner circumferential side face of the through hole, the bottom face of the pushing block is a curved face, and when the bottom face of the pushing block slides to the bottommost portion of the through hole, the bottom face of the pushing block makes up for the portion, missing in the through hole, of the first curved face. The bottom surface of the body and the bottom surface of the push block jointly form the complete first curved surface; the power assembly is located on the top face of the push block and exerts limiting acting force in the axial direction of the through hole on the push block, so that the bottom face of the push block is always kept in the state that the bottom face of the push block is located at the bottommost portion of the through hole. The device not only can exhaust, but also can prevent overflow, and can clean the inner side wall of the exhaust hole.

Description

Technical Field

[0001] The utility model relates to the field of extrusion equipment, in particular to an exhaust device for a screw extruder. Background Art

[0002] The main machine of the plastic granulator is an extruder, which consists of an extrusion system, a transmission system and a heating and cooling system.

[0003] A screw extruder is a commonly used extruder. The screw extruder includes a heating chamber and a screw that rotates continuously in the heating chamber. The outside of the heating chamber is usually covered with a heat insulation board to prevent workers from being burned.

[0004] During the production process, a screw extruder generates exhaust gases within the heating chamber. These gases need to be exhausted during the plastic conveying process. Therefore, several exhaust ports are typically installed at the top of the screw extruder's heating chamber, with the tops of the ports extending through the insulation plate located at the top of the chamber. However, in actual production, molten plastic easily overflows from these ports, causing them to become clogged and ineffective. During the extrusion and heating process in the screw extruder, the molten plastic is compressed within the confined space. Therefore, as it flows through the exhaust ports, it expands and, due to its viscosity, some of the melt (molten plastic) cannot easily re-enter the screw extruder for conveying. This phenomenon is unavoidable, and the current method relies on manual removal of the overflowing melt. If the overflowing melt remains undetected, it often spreads everywhere, causing significant trouble in cleaning up the production area. Summary of the Invention

[0005] In view of this, it is necessary to provide a screw extruder exhaust device that can exhaust and prevent overflow, and can also clean the inner side wall of the exhaust hole.

[0006] In order to solve the above technical problems, the technical solution of the utility model is: an exhaust device for a screw extruder, comprising:

[0007] A body, wherein the bottom surface of the body has a first curved surface matching the outer circumference of the screw, and the first curved surface has a through hole penetrating the top surface of the body;

[0008] a push block, the push block being slidably connected to the through hole, the outer peripheral side surface of the push block being in contact with the inner peripheral side surface of the through hole, the bottom surface of the push block being a curved surface, and when the bottom surface of the push block slides to the bottom of the through hole, the bottom surface of the push block compensates for the missing portion of the first curved surface in the through hole, so that the bottom surface of the main body and the bottom surface of the push block together constitute a complete first curved surface;

[0009] A power assembly, which is located on the top surface of the push block and applies a defined force along the axial direction of the through hole to keep the bottom surface of the push block always at the bottommost position of the through hole.

[0010] Further, the power assembly is a spring or a cylinder.

[0011] Further, it further includes a slide rail fixedly connected to the screw extruder, and a slider is fixedly connected to the lower side of the top surface of the push block and is slidably connected to the slide rail.

[0012] Further, the power assembly is fixedly connected to the top end of the slide rail.

[0013] Further, the axial direction of the through hole has an angle with the horizontal direction, and the angle is greater than 30° and less than 75°.

[0014] Further, when the screw extruder is a twin-screw extruder, the bottom surface of the body has two first curved surfaces matching the outer peripheral side of the screw, and only one of the first curved surfaces has the through hole.

[0015] Further, a protective box is fixedly connected to the body, and the protective box covers the push block and the slide rail.

[0016] Further, the top of the protective box has an openable cover plate.

[0017] Further, the side wall or the cover plate of the protective box has air vents.

[0018] Compared with the prior art, the present utility model has the following beneficial effects: By arranging a push block in the exhaust through hole and applying a rated thrust to the push block, when the gas pressure in the extruder is greater than the thrust, the push block is extruded from the through hole to achieve exhaust. After the air pressure in the extruder drops, the push block is pressed back into the through hole under the action of the rated thrust, ensuring the pressure in the extruder and being able to push the molten material on the side wall of the through hole back into the extruder. The structure is simple, the functions are diverse, and it is convenient to use.

[0019] To make the above and other purposes, features and advantages of the present utility model more obvious and understandable, the following specific preferred embodiments are given in conjunction with the accompanying drawings and are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view of an embodiment of the present utility model.

[0021] Figure 2 It is a cross-sectional view of an embodiment of the present utility model.

[0022] Figure 3 It is a perspective view of the embodiment of the present utility model after removing the protective box.

[0023] In the figure: 1 - body, 11 - first curved surface, 12 - through hole, 13 - slide rail, 2 - push block, 21 - slider, 3 - air cylinder, 4 - protective box, 41 - cover plate, 42 - ventilation hole. Specific embodiments

[0024] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on the specific embodiments, structures, features and effects of the present invention as follows.

[0025] As Figures 1 - 3 shown, an exhaust device for a screw extruder includes: a body 1, a push block 2, a power assembly and a protective box 4. The body 1 is detachably and fixedly connected to the housing of the screw extruder and forms a part of the housing of the screw extruder.

[0026] The bottom surface of the body 1 has a first curved surface 11 that matches the outer peripheral side of the screw inside the screw extruder. If the screw extruder is a twin-screw extruder, then the bottom surface of the body correspondingly has two first curved surfaces. However, whether it is a single-screw extruder or a twin-screw extruder, there is and only one first curved surface 11 with a through hole 12 penetrating the top surface of the body 1.

[0027] The screw is horizontally placed. The axial direction of the through hole 12 can be perpendicular to the axial direction of the screw and vertically upward. However, in order to increase the moving stroke of the molten material and increase the difficulty of the molten material overflowing from the through hole, the axial direction of the through hole 12 is designed to be inclined with respect to the horizontal direction. The axial direction of the through hole 12 and the horizontal direction have an included angle, and the included angle is greater than 30° and less than 75°. In this embodiment, the included angle is 65°.

[0028] The power assembly can be a spring or an air cylinder. In this embodiment, an air cylinder 3 is adopted. The front end of the piston rod of the air cylinder 3 is fixedly connected to the top surface of the push block 2.

[0029] The push block 2 is slidably connected to the through hole 12. The outer peripheral side surface of the push block 2 is in contact with the inner peripheral side surface of the through hole. The bottom surface of the push block 2 is a curved surface. When the bottom surface of the push block 2 slides to the bottom of the through hole 12, the bottom surface of the push block 2 makes up for the part of the first curved surface 11 missing in the through hole, so that the bottom surface of the body 1 and the bottom surface of the push block 2 jointly form a complete first curved surface; the air cylinder 3 always exerts a defined acting force on the push block 2, so that the bottom surface of the push block 2 always maintains a state at the bottom of the through hole, that is, the first curved surface 11 maintains a complete state.

[0030] To make the movement of the push block 2 more stable, a slide rail 13 is fixedly connected to the screw extruder. A slider 21 slidably connected to the slide rail 13 is fixedly connected to the lower side of the top surface of the push block 2. The air cylinder 3 is fixedly connected to the top end of the slide rail 13.

[0031] The protective box 4 is fixedly connected to the body 1, and the protective box 4 covers the push block 2 and the slide rail 13. The top of the protective box 4 has an openable cover plate 41, and the side wall or the cover plate 41 of the protective box 4 has air vents 42.

[0032] When the gas pressure in the screw extruder is greater than the force exerted by the cylinder on the push block, the internal air pressure of the screw extruder extrudes the push block out of the through hole to achieve exhaust; after the air pressure in the screw extruder drops after exhaust and is less than the force exerted by the cylinder on the push block, the push block is pressed back into the through hole under this force. The reset of the push block not only ensures the pressure in the extruder, but also returns the molten material on the side wall of the through hole back into the extruder, and at the same time avoids the phenomenon of overflow during the operation of the extruder, playing multiple roles.

[0033] The above is only the preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments of equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An exhaust device for a screw extruder, characterized in that, Including: A body, the bottom surface of the body has a first curved surface that matches the outer peripheral side of the screw, and a through hole that penetrates the top surface of the body is provided on the first curved surface; A push block, the push block is slidably connected to the through hole, the outer peripheral side surface of the push block fits with the inner peripheral side surface of the through hole, the bottom surface of the push block is a curved surface, when the bottom surface of the push block slides to the bottommost part of the through hole, the bottom surface of the push block makes up for the part missing from the first curved surface in the through hole, so that the bottom surface of the body and the bottom surface of the push block together form the complete first curved surface; A power assembly, the power assembly is located on the top surface of the push block and applies a defined acting force along the axial direction of the through hole to the push block, so that the bottom surface of the push block always remains in the state of being at the bottommost part of the through hole.

2. The exhaust device for a screw extruder according to claim 1, characterized in that: The power assembly is a spring or a cylinder.

3. The exhaust device for a screw extruder according to claim 2, characterized in that: It further includes a slide rail fixedly connected to the screw extruder, and a slider slidably connected to the slide rail is fixedly connected to the lower side of the top surface of the push block.

4. The exhaust device for a screw extruder according to claim 3, wherein: The power assembly is fixedly connected to the top end of the slide rail.

5. The exhaust device for a screw extruder according to claim 1, wherein: The axial direction of the through hole has an included angle with the horizontal direction, and the included angle is greater than 30° and less than 75°.

6. The exhaust device for a screw extruder according to claim 1, characterized in that: When the screw extruder is a twin-screw extruder, the bottom surface of the body has two first curved surfaces that match the outer peripheral side of the screw, and only one of the first curved surfaces has the through hole.

7. The exhaust device for a screw extruder according to claim 4, characterized in that: A protective box is fixedly connected to the body, and the protective box covers the push block and the slide rail.

8. The exhaust device for a screw extruder according to claim 7, wherein: The top of the protective box has an openable cover plate.

9. The exhaust device for a screw extruder according to claim 8, characterized in that: The side wall or the cover plate of the protective box has air vents.

Images