Combined injection unit for pushing molten HDPE

Abstract

The combined injection device for pushing molten HDPE described in the present invention comprises a barrel and a gun head. A pressure relief head is added between the barrel and the gun head. A pressure relief hole is provided at the contact position between the barrel and the inner end of the pressure relief head. The inner end of the pressure relief head blocks the pressure relief hole. The barrel, the pressure relief head and the gun head are connected. The outer end of the pressure relief head is a flange, the outer diameter of the flange matches the outer diameter of the barrel, and the flange is connected to the end face of the barrel through a number of bolts. The outer diameter of the inner end of the pressure relief head is interference fit with the inner diameter of the barrel. A groove is provided between the flange and the inner end of the pressure relief head. A pin passes through the pin hole on the barrel wall and is fixed in the groove position of the pressure relief head. The gun head is fixed to the flange of the pressure relief head through a small flange and a small bolt. When the electrical protection function fails, when the injection port is blocked, the material flow pushes the pressure relief head forward until the fixing bolts and the pin are pulled off, the pressure relief hole of the barrel and the material flow are connected, and the pressure relief head falls off to avoid barrel bursting.

Description

Technical Field

[0001] The invention relates to an injection device, in particular to a combined injection device for pushing molten HDPE. Background Art

[0002] After the pipe body is made, the C-type pipe represented by high-rib winding pipe, double high-rib winding pipe, inner rib pipe, hollow wall pipe, hollow wall plastic steel pipe, etc. produced by cold winding process needs to make the socket joints at both ends of the pipe body. At this time, an injection device is used to push the molten HDPE. The injection device is connected to the extruder. The injection device of the existing extruder is not equipped with a safety protection device-a pressure relief head. When the injection port is blocked, when the injection is started, once the pressure in the barrel exceeds the maximum design pressure that the barrel can withstand (generally 25-40MPa), the barrel will burst, causing safety hazards such as casualties of operators. Summary of the invention

[0003] The purpose of the present invention is to provide a combined injection device for pushing molten HDPE, which consists of a barrel, a pressure relief head and a gun head. When the electrical protection function fails and the injection port is blocked, the material flow pushes the pressure relief head forward until the fixing bolts and pins are broken, the pressure relief hole of the barrel and the material flow are connected, and the pressure relief head falls off the barrel, thereby achieving complete pressure relief and avoiding barrel explosion.

[0004] The present invention is implemented in this way: the combined injection device for pushing molten HDPE includes a barrel and a gun head, a pressure relief head is added between the barrel and the gun head, and the barrel, the pressure relief head and the gun head are connected.

[0005] The outer end of the pressure relief head described in the present invention is a flange, the outer diameter of the flange matches the outer diameter of the barrel, and the flange is connected to the end face of the barrel through a plurality of bolts; the outer diameter of the inner end of the pressure relief head is interference fit with the inner diameter of the barrel, and the gun head is fixed to the flange of the pressure relief head through a small flange and small bolts.

[0006] The invention provides a groove between the flange and the inner end of the pressure relief head, and a pin passes through a pin hole on the barrel wall and is fixed at the groove position of the pressure relief head.

[0007] The present invention provides a plurality of pressure relief holes at the contact position between the barrel and the inner end of the pressure relief head, and the inner end of the pressure relief head blocks the pressure relief holes.

[0008] The present invention is also provided with two electrical protections, one is that the injection device is connected to the motor torque device; the other is that the injection device is connected to the high-temperature melt pressure transmitter and the high-temperature melt pressure sensor.

[0009] In order to prevent the pressure relief head from falling off and injuring people, the present invention provides a protective net in front of the injection device.

[0010] The beneficial effect of the present invention is that when the electrical protection function fails and the injection port is blocked, the material flow pushes the pressure relief head forward until the fixing bolts and pins are pulled off, the pressure relief hole of the barrel and the material flow are connected, and the pressure relief head falls off the barrel, thereby achieving complete pressure relief and avoiding barrel explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a dispersion schematic diagram of the present invention.

[0012] Figure 2 It is a cross-sectional schematic diagram of the present invention.

[0013] In the figure: 1. barrel, 2. gun head, 3. pressure relief head, 4. inner end of pressure relief head, 5. pressure relief hole, 6. flange, 7. bolt, 8. groove, 9. pin, 10. small flange, 11. small bolt, 12. pin hole. DETAILED DESCRIPTION

[0014] The combined injection device for pushing molten HDPE of the present invention is as follows: Figure 1 , 2 As shown, it includes a barrel 1 and a gun head 2, a pressure relief head 3 is added between the barrel 1 and the gun head 2, a pressure relief hole 5 is provided at the contact position between the barrel 1 and the inner end 4 of the pressure relief head, and the inner end 4 of the pressure relief head blocks the pressure relief hole 5; the barrel 1, the pressure relief head 3, and the gun head 2 are connected. The outer end of the pressure relief head of the present invention is a flange 6, the outer diameter of the flange matches the outer diameter of the barrel, and the flange 6 is connected to the end face of the barrel through a plurality of bolts 7; the outer diameter of the inner end 4 of the pressure relief head is interference fit with the inner diameter of the barrel 1, and a groove 8 is provided between the flange 6 of the pressure relief head and the inner end 4 of the pressure relief head, and a pin 9 passes through the pin hole 12 on the barrel wall and is fixed to the groove 8 position of the pressure relief head; the gun head 2 is fixed to the flange 6 of the pressure relief head through a small flange 10 and a small bolt 11.

[0015] For the extruder, firstly, in terms of electrical control, two-level protection functions are added. One is that the injection device is connected to the motor torque protection device; the other is that the injection device is connected to the high-temperature melt pressure transmitter and high-temperature melt pressure sensor. That is, melt pressure protection and torque protection. Once the injection pressure exceeds the set value, or the motor torque exceeds the set value, the system will automatically cut off the power output and stop the machine to alarm, so as to avoid the injection device barrel from bursting.

[0016] In the case of failure of the electrical protection function of the present invention, when the injection port is blocked, the material flow pushes the pressure relief head forward until the fixing bolts and pins are pulled off, the pressure relief hole of the barrel and the material flow are connected, and the pressure relief head falls off the barrel, thereby achieving complete pressure relief and preventing the barrel from bursting. In order to prevent the pressure relief head from falling off and injuring people, the present invention is provided with a protective net in front of the injection device.

[0017] In the present invention, a plurality of pressure relief holes may be provided at intervals at the contact position between the barrel 1 and the inner end 4 of the pressure relief head. The pressure relief holes are arranged in a circle on the barrel wall, and the inner end 4 of the pressure relief head blocks the pressure relief holes. Once the injection port is blocked, the material flow pushes the pressure relief head forward until the fixing bolts and pins are pulled off, and the barrel pressure relief hole and the material flow are connected. The multiple pressure relief holes can quickly divert and relieve pressure to avoid explosion.

[0018] The motor torque protection device of the present invention comprises: 1. a three-phase asynchronous motor, model: R225S-4, power: 37KW, voltage: 380V, current: 69.8A; 2. a frequency converter ACS510-01-125A-4; voltage: 380V, current: 125A.

[0019] The motor torque protection of the present invention is controlled by the protection circuit of the frequency converter. The frequency converter parameters are adjusted to 70% of the rated current. When the protection circuit detects the current and voltage of the main circuit, overload or overvoltage, etc., the asynchronous motor stops working.

[0020] The high-temperature melt pressure transmitter of the present invention is PT124B-121-M14-152 / 460, with a voltage of 24V, a measuring range of 0 to 50MPa, and an accuracy of ±1.0%FS.

[0021] High temperature melt pressure sensor: voltage 10V, range: 0-50MPa, diaphragm temperature resistance: 400°C. The high temperature melt pressure sensor of the present invention is mainly used for pressure measurement and control of molten materials under high temperature conditions.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combined injection device for pushing molten HDPE, comprising a barrel (1) and a gun head (2), characterized in that: A pressure relief head (3) is provided between the barrel (1) and the gun head (2), and the barrel (1), the pressure relief head (3) and the gun head (2) are connected; the outer end of the pressure relief head (3) is a flange (6), the outer diameter of the flange (6) matches the outer diameter of the barrel (1), and the flange (6) is connected to the end face of the barrel via a plurality of bolts (7); the outer diameter of the inner end (4) of the pressure relief head is interference fit with the inner diameter of the barrel (1), and the gun head is fixed to the flange of the pressure relief head via a small flange and small bolts; a groove (8) is provided between the flange (6) of the pressure relief head (3) and the inner end (4) of the pressure relief head, and a pin (9) passes through a pin hole (12) on the barrel wall and is fixed to the groove (8) of the pressure relief head; a plurality of pressure relief holes (5) arranged at intervals are provided at the contact position between the barrel (1) and the inner end (4) of the pressure relief head, and the inner end (4) of the pressure relief head blocks the pressure relief holes (5).

2. The combined injection device for pushing molten HDPE according to claim 1 is characterized in that: The injection device is connected to the motor torque device.

3. The combined injection device for pushing molten HDPE according to claim 1 or 2, characterized in that: The injection device is connected with a high-temperature melt pressure transmitter and a high-temperature melt pressure sensor.

4. The combined injection device for pushing molten HDPE according to claim 1 or 2, characterized in that: A protective net is arranged in front of the injection device.

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