A thermoplastic resin injection device for precisely controlling inert gas

Abstract

This invention provides a thermoplastic resin injection device for precise control of inert gas, comprising a gas supply unit, a screw conveying mechanism, a gas pipeline, and a controller. The screw conveying mechanism includes, along the conveying direction, a feeding section, a mixing section, and an ejection section. The feeding section has a feed inlet, and the mixing section has an air inlet. One end of the gas pipeline has a flow control valve connected to the gas supply unit, and the other end has a check valve connected to the air inlet of the screw conveying mechanism. Along the gas conveying direction, a first pressure gauge, a pressure reducing valve, and a second pressure gauge are connected in series in the gas pipeline. A first pressure control valve is connected between the flow control valve and the first pressure gauge, and a second pressure control valve is located between the second pressure gauge and the check valve. This invention is a thermoplastic resin injection device with a simple structure, convenient operation, and automatic control of flow and pressure for precise control of inert gas, while also saving labor costs.

Description

Technical Field

[0001] The utility model relates to the field of a thermoplastic resin injection device, in particular to a thermoplastic resin injection device capable of accurately controlling inert gas. Background Art

[0002] Injection molding machines and extruders are two common types of equipment in the plastic processing industry. They play an important role in the production of plastic products. The same point in the production process of the two is that after the plastic particles are heated and melted, the molten resin is pushed into the mold through the screw.

[0003] In the existing injection molding or extrusion molding production process, inert gas is usually added to the molten resin during the screw conveying process, which prevents resin oxidation, improves fluidity, reduces bubbles, improves reaction efficiency, and improves resin processing quality and efficiency. However, during the existing inert gas addition process, the flow and pressure of the inert gas are controlled by manually controlling the valve, and only the pressure reducing valve and the check valve are set on the air pipe. After the gas passes through the pressure reducing valve, the gas pressure is still unstable. If this unstable gas is integrated into the resin, the physical properties of the resin are also unstable. It not only wastes manpower but also cannot accurately control the flow. The unstable gas pressure and flow will cause the mixing ratio to fluctuate too much. In a plastic part, the physical properties of the local area are different from those of other areas, and each part is also different, so the quality of the plastic part is unstable. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide a thermoplastic resin injection device for accurately controlling inert gas with a simple structure, convenient operation, and automatic control of flow and pressure, while also saving labor costs.

[0005] The utility model is implemented as follows: a thermoplastic resin injection device for accurately controlling inert gas, comprising

[0006] a gas supply unit;

[0007] A screw conveying mechanism, which includes a feeding section, a mixing section and a pushing section in sequence along the conveying direction, wherein the feeding section is provided with a feeding port, and the mixing section is provided with an air inlet;

[0008] a gas pipeline, one end of which is provided with a flow control valve and connected to the gas supply unit, and the other end of which is provided with a check valve and connected to the air inlet of the screw conveying mechanism, a first pressure gauge, a pressure reducing valve and a second pressure gauge are sequentially connected in series in the gas pipeline along the gas conveying direction, a first pressure control valve is connected to the gas pipeline between the flow control valve and the first pressure gauge, and a second pressure control valve is provided between the second pressure gauge and the check valve;

[0009] A controller is connected to control the flow control valve, the check valve, the first pressure gauge, the pressure reducing valve, the second pressure gauge, the first pressure control valve and the second pressure control valve.

[0010] Furthermore, a heating device is provided outside the screw conveying mechanism.

[0011] Furthermore, the gas supply unit is a gas tank.

[0012] The advantages of the utility model are: the utility model can be used to control the gas output of the gas supply unit by setting a flow control valve; by setting a first pressure control valve, it can be used to automatically release pressure when the gas pressure in the gas pipeline suddenly increases, and can also be used to exhaust the original gas in the gas pipeline when changing the gas; by setting a first pressure gauge and a second pressure gauge on the gas pipeline, it can be used to detect the pressure on both sides of the pressure reducing valve; by setting a second pressure control valve, it can be used to more accurately adjust the gas pressure in the gas pipeline, so that the pressure of the inert gas entering the screw conveying mechanism is more stable. The utility model is a thermoplastic resin injection device that accurately controls inert gas with a simple structure, easy operation, and automatic control of flow and pressure, and can also save labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the embodiments with reference to the accompanying drawings.

[0014] Figure 1 The utility model is a schematic structural diagram of a thermoplastic resin injection device for accurately controlling inert gas.

[0015] Explanation of the accompanying drawings: gas supply unit 1, screw conveying mechanism 2, feeding section 21, mixing section 22, pushing section 23, feeding port 211, air inlet 221, gas pipeline 3, flow control valve 31, check valve 32, first pressure gauge 33, pressure reducing valve 34, second pressure gauge 35, first pressure control valve 36, second pressure control valve 37, controller 4. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] like Figure 1 As shown, a thermoplastic resin injection device for accurately controlling inert gas includes a gas supply unit 1, a screw conveying mechanism 2, a gas pipeline 3 and a controller 4; the gas supply unit 1 is a gas tank, and the gas tank contains inert gas.

[0018] The screw conveying mechanism 2 is provided with a heating device (not shown) on the outside, and the heating device is used to heat the screw conveying mechanism 2. The heating device is a prior art and will not be described in detail here. The screw conveying mechanism 2 includes a feeding section 21, a mixing section 22 and a pushing section 23 in sequence along the conveying direction. The feeding section 21 is provided with a feeding port 211 for feeding thermoplastic resin into the feeding section, and the mixing section 22 is provided with an air inlet 221 for introducing an inert gas into the mixing section.

[0019] A flow control valve 31 is provided at one end of the gas pipeline 3 and connected to the gas supply unit 1, and a check valve 32 is provided at the other end and connected to the air inlet 221 of the screw conveying mechanism 2. A first pressure gauge 33, a pressure reducing valve 34 and a second pressure gauge 35 are sequentially connected in series on the gas pipeline 3 along the gas conveying direction. A first pressure control valve 36 is connected to the gas pipeline 3 between the flow control valve 31 and the first pressure gauge 33. The first pressure control valve 36 can be used to open the first pressure control valve 36 for automatic pressure relief and stabilizing the pressure and flow of the gas when the gas pressure in the gas pipeline 3 suddenly increases, for example, when the gas tank or the external gas storage pump is quickly opened, the gas coming out fluctuates too much, and the gas pressure in the gas pipeline 3 suddenly exceeds the set pressure. It can also be used to exhaust the original gas in the gas pipeline 3 when changing the gas. A second pressure control valve 37 is provided between the second pressure gauge 35 and the check valve 32. Because the accuracy of the flow and pressure after passing through the pressure reducing valve is not high enough, the second pressure control valve 37 can be provided to more accurately adjust the gas pressure in the gas pipeline 3.

[0020] The controller 4 is connected to control the flow control valve 31, the check valve 32, the first pressure gauge 33, the pressure reducing valve 34, the second pressure gauge 35, the first pressure control valve 36 and the second pressure control valve 37. The data detected by the first pressure gauge 33 and the second pressure gauge 35 are fed back to the controller 4, and the controller 4 controls the opening and closing of the first pressure control valve 36 and the second pressure control valve 37.

[0021] Working principle: First, after the gas supply unit 1 is connected to the screw conveying mechanism 2 through the gas pipeline 3, the flow control valve 31, the check valve 32 and the pressure reducing valve 34 are opened through the controller 4, so that the gas supply unit 1 provides inert gas to the screw conveying mechanism 2 through the gas pipeline 3. When the inert gas passes through the pressure reducing valve 34, the inert gas can be decompressed and then flow into the screw conveying mechanism 2. The check valve 34 is used to prevent the molten resin from flowing back into the gas pipeline 3. When the second pressure gauge 35 detects that the pressure and flow are unstable after decompression, the value is fed back to the controller 4, and the control The controller 4 precisely adjusts the pressure and flow rate in the gas pipeline 3 by opening the second pressure controller 37, so that the flow rate and pressure of the inert gas entering the screw conveying mechanism 2 are more stable, the mixing ratio of the gas and the resin fluctuates less, and the product quality is more stable. Then, the thermoplastic resin material is fed into the feed port 211 of the screw conveying mechanism 2, and is heated to become a molten resin and is conveyed to the mixing section 22 by the screw. When the molten resin passes through the mixing section 22, the inert gas can be dissolved into the resin under the screw pressure and the resin temperature, and finally it is extruded through the ejection section 23 or injection molded into the mold for molding.

[0022] When it is necessary to replace the gas tank or connect an external gas storage pump and quickly open the flow control valve 31, the gas pressure is unstable. The first pressure gauge 33 may detect that the pressure in the gas pipeline 3 is greater than the preset value, and the value is fed back to the controller 4. The controller 4 controls the first pressure control valve 36 to open for automatic pressure relief until the pressure and flow in the gas pipeline 3 reach the preset value, and then closes the first pressure control valve 36. When the gas is better, the first pressure control valve 36 can be opened by the controller 4 to exhaust the original gas in the gas pipeline 3.

[0023] The advantages of the utility model are: the utility model can be used to control the gas output of the gas supply unit 1 by setting the flow control valve 31; by setting the first pressure control valve 36, it can be used to automatically release the pressure when the gas pressure in the gas pipeline 3 suddenly increases, and can also be used to exhaust the original gas in the gas pipeline 3 when changing the gas; by setting the first pressure gauge 33 and the second pressure gauge 35 on the gas pipeline 3, it can be used to detect the pressure on both sides of the pressure reducing valve 34, and feed back the value to the controller 4; by setting the second pressure control valve 37, it can be used to more accurately adjust the gas pressure in the gas pipeline 3, so that the pressure of the inert gas entering the screw conveying mechanism 2 is more stable. The utility model is a thermoplastic resin injection device for accurately controlling inert gas with simple structure, convenient operation, automatic control of flow and pressure, and can also save labor costs.

[0024] Although the specific implementation methods of the present invention are described above, those skilled in the art should understand that the specific embodiments described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A thermoplastic resin injection device for accurately controlling inert gas, characterized in that: comprising a gas supply unit; A screw conveying mechanism, which includes a feeding section, a mixing section and a pushing section in sequence along the conveying direction, wherein the feeding section is provided with a feeding port, and the mixing section is provided with an air inlet; a gas pipeline, one end of which is provided with a flow control valve and connected to the gas supply unit, and the other end of which is provided with a check valve and connected to the air inlet of the screw conveying mechanism, a first pressure gauge, a pressure reducing valve and a second pressure gauge are sequentially connected in series in the gas pipeline along the gas conveying direction, a first pressure control valve is connected to the gas pipeline between the flow control valve and the first pressure gauge, and a second pressure control valve is provided between the second pressure gauge and the check valve; A controller is connected to control the flow control valve, the check valve, the first pressure gauge, the pressure reducing valve, the second pressure gauge, the first pressure control valve and the second pressure control valve.

2. A thermoplastic resin injection device for accurately controlling inert gas according to claim 1, characterized in that: A heating device is arranged outside the screw conveying mechanism.

3. A thermoplastic resin injection device for accurately controlling inert gas according to claim 1, characterized in that: The gas supply unit is a gas tank.

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