Manufacturing method of high-load PP inspection well

Abstract

The invention belongs to the technical field of municipal engineering plastic products, and particularly relates to a manufacturing method of a high-load PP (polypropylene) inspection well, which is characterized in that PP resin with high flowability and high rigidity is selected, a glass fiber reinforced material with a proper proportion is added, and structural reinforcement treatment is performed, so that the bearing capacity of the PP inspection well is remarkably improved, and the service life of the PP inspection well is prolonged. And larger external pressure can be borne, and the problems of deformation, fracture and the like under the high-load working condition are effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of municipal engineering plastic products, and in particular relates to a method for manufacturing a high-load PP inspection well. Background Art

[0002] Inspection wells are designed for easy maintenance of urban underground infrastructure, including power supply, water supply, drainage, sewage, communications, cable TV, gas pipes, and streetlight lines. They are typically located at pipeline intersections, bends, changes in pipe diameter or slope, and at regular intervals along straight pipe sections to facilitate regular inspection of ancillary structures.

[0003] With the continuous development of urban construction, inspection wells, as an important part of the city's underground pipe network system, are being used more and more. Traditional inspection wells are mostly made of bricks or concrete, and have problems such as long construction period, heavy weight, easy leakage, and poor corrosion resistance. In recent years, inspection wells made of PP (polypropylene) have gradually been widely used due to their advantages such as light weight, corrosion resistance, and easy installation. However, existing PP inspection wells are prone to deformation, rupture, etc. when facing high-load conditions. In particular, the performance of bearing the axial load of pipes is limited, and it cannot meet the growing needs of urban construction. Therefore, it is of great practical significance to develop a manufacturing method that can effectively improve the bearing capacity of PP inspection wells. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned technical problems and provide a method for manufacturing a high-load PP inspection well, which significantly improves the bearing capacity of the PP inspection well and effectively avoids problems such as deformation and rupture under high-load conditions.

[0005] In view of this, the present invention provides a method for manufacturing a high-load PP inspection well, comprising: Raw material configuration: PP resin with a melt flow rate ≥10g / 10min (190℃, 2.16kg) and a tensile yield strength ≥45MPa is used as the base material, with 15%-30% glass fiber (length 3mm-6mm), 5%-10% POE toughening agent, 0.2%-0.3% hindered phenol antioxidant and 0.3%-0.5% benzophenone UV absorber added; Mixing and granulation: Mix at 180-220℃ at 500-800r / min for 10-35 minutes, melt granulate through twin-screw extruder, extrusion temperature 180-225℃; Injection molding: The granulated material is injected into the mold cavity through the injection molding machine at an injection temperature of 180-230℃, a pressure of 70-90MPa, and an injection speed of 40cm³ / s-60cm³ / s. After the injection is completed, the pressure is maintained at 70%-90% of the injection pressure for 15-20s, and then cooled and demolded.

[0006] In the above technical solution, further, the extrusion process of the twin-screw extruder is divided into multiple temperature ranges, wherein zone one is 180°C-190°C, zone two is 190°C-200°C, zone three is 200°C-210°C, zone four is 210°C-220°C, zone five is 215°C-225°C, and the head temperature is 215°C-225°C.

[0007] In the above technical solution, further, the twin-screw extruder includes: The machine body includes a material collecting seat and five cylinders connected in sequence along the axial direction. A machine head is provided on the cylinder away from the material collecting seat. A flow channel is provided in the material collecting seat. The flow channel passes through the five cylinders and is connected to the machine head. Feed bin, which is arranged on the aggregate seat and is connected to the flow channel; Two screws are arranged in parallel in the flow channel. Both screws are axially distributed throughout the flow channel. One end of each screw passes through the side wall of the aggregate seat and extends to the outside of the aggregate seat. A driving mechanism, which is used to drive the two screws to rotate; Five groups of heating mechanisms are respectively arranged inside the five cylinders, and the heating mechanisms can heat the inside of the corresponding cylinders; Five sets of temperature sensors are respectively arranged inside the five cylinders, and the temperature sensors can monitor the temperature inside the corresponding cylinders in real time; The circuit control device can respectively control the driving mechanism, five groups of heating mechanisms, and five groups of temperature sensors.

[0008] In the above technical solution, further, a mounting ring groove is provided on the inner wall of the cylinder, the heating mechanism includes a thermal insulation layer, a resistance wire and a heat-conductive cover, the resistance wire is spirally distributed in the mounting ring groove, the heat-conductive cover is arranged at the notch of the mounting ring groove for sealing the resistance wire, and the thermal insulation layer is arranged on the side of the resistance wire away from the heat-conductive cover.

[0009] In the above technical solution, further, the driving mechanism includes a motor, a reducer, a driving gear, a driven gear and a transmission gear set, the driving gear and the driven gear are respectively arranged on two screws, the transmission gear set is used to connect the driving gear with the driven gear, and the motor is connected to a screw through the reducer.

[0010] In the above technical solution, further, the injection molding machine is divided into multiple temperature ranges, including a feeding section of 180°C-190°C, a compression section of 200°C-210°C, a melting zone of 210°C-220°C, a homogenizing zone of 220°C-230°C, and a nozzle temperature of 200°C-210°C.

[0011] A high-load PP inspection well is manufactured by the aforementioned manufacturing method. The inspection well includes a well shaft. Reinforcing ribs are arranged on the outer wall of the well shaft, and the reinforcing ribs are distributed in a spiral shape.

[0012] The beneficial effects of the present invention are: 1. By selecting high-fluidity and high-rigidity PP resin, adding a suitable proportion of glass fiber reinforcement materials, and performing structural reinforcement treatment, the bearing capacity of the PP inspection well is significantly improved, capable of withstanding greater external pressure, and effectively avoiding deformation, cracking and other problems under high-load conditions.

[0013] 2. By adding toughening agents, antioxidants, UV absorbers and other additives, the toughness, aging resistance and weather resistance of the PP inspection well are improved, and the service life of the inspection well is extended.

[0014] 3. Improve the uniformity of the melt and the uniformity of fiber dispersion by performing step-by-step temperature control on the twin-screw extruder and injection molding machine.

[0015] 4. By arranging spirally distributed reinforcement ribs on the outer wall of the wellbore, the axial bearing capacity of the wellbore and the lateral pressure capacity of the soil are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the twin-screw extruder in the present invention.

[0018] Figure 2 for Figure 1 Schematic diagram of the locally enlarged structure at point A in the middle.

[0019] Figure 3 Schematic diagram of the connection between two adjacent barrels of the twin-screw extruder in the present invention.

[0020] Figure 4 This is a schematic diagram of the spiral reinforcement ribs provided on the PP inspection well in the present invention.

[0021] The marks in the figure are: 1. Aggregate seat; 2. Cylinder; 201. Mounting ring groove; 3. Machine head; 4. Flow channel; 5. Feed bin; 6. Screw; 7. Drive mechanism; 801. Insulation layer; 802. Resistance wire; 803. Thermal cover; 9. Connecting tube; 10. Shaft; 11. Reinforcement ribs. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0024] Example 1 This embodiment provides a method for manufacturing a high-load PP inspection well, comprising: Raw material configuration: PP resin with a melt flow rate ≥10g / 10min (190°C, 2.16kg) and a tensile yield strength ≥45MPa is used as the base material. A certain proportion of glass fiber reinforcement is added, with the glass fiber length controlled between 3mm and 6mm, and the addition amount being 15% to 30% of the PP resin weight. Appropriate amounts of toughening agents, antioxidants, and UV absorbers are added to improve the overall performance of the material. The toughening agent is ethylene-octene copolymer (POE), with an addition amount of 5% to 10% of the PP resin weight; the antioxidant is hindered phenol antioxidant 1010, with an addition amount of 0.2% to 0.3% of the PP resin weight; and the UV absorber is benzophenone-based UV absorber UV-9, with an addition amount of 0.3% to 0.5% of the PP resin weight.

[0025] Mixing and Granulation: Add the prepared PP resin, glass fiber reinforcement, and additives according to the set ratio into a high-speed mixer. Mix uniformly at a temperature of 180°C-220°C and a speed of 500-800 rpm for 10-35 minutes. The mixed material is melt-granulated in a twin-screw extruder. The extruder section temperatures are set as follows: Zone 1: 180°C-190°C, Zone 2: 190°C-200°C, Zone 3: 200°C-210°C, Zone 4: 210°C-220°C, Zone 5: 215°C-225°C, and die head 3: 215°C-225°C. The granulated material is water-cooled, pelletized, and dried for later use.

[0026] Injection molding: The granulated material is added to the injection molding machine hopper. The rotating screw 6 of the injection molding machine conveys the material to the heated barrel for melting and plasticization. The temperature settings of each section of the injection molding machine are as follows: 180°C-190°C for the feeding section, 200°C-210°C for the compression section, 210°C-220°C for the melting zone, 220°C-230°C for the homogenization zone, and 200°C-210°C for the nozzle. The molten material is injected into the mold cavity at a constant pressure and speed, with the injection pressure controlled between 70MPa-90MPa and the injection speed between 40cm³ / s and 60cm³ / s. After injection, the pressure is maintained at 70%-90% of the injection pressure for 15-20 seconds, followed by cooling and demolding. The cooling time is adjusted according to the size and wall thickness of the inspection well, generally between 30-40 seconds, to ensure sufficient cooling and deformation of the well.

[0027] The mold is specially designed based on the structural requirements of high-load PP inspection wells. It utilizes a modular structure, consisting of an upper mold, lower mold, and core. The mold cavity surface is precision-machined to a roughness Ra below 0.8μm to ensure surface quality after the inspection well is formed. Cooling channels are also incorporated into the mold to optimize the cooling system layout, ensuring uniform mold temperature during the molding process and improving molding efficiency.

[0028] In this embodiment, by selecting a high-flow, high-rigidity PP resin, adding an appropriate proportion of glass fiber reinforcement, and performing structural reinforcement, the load-bearing capacity of the PP manhole is significantly improved, allowing it to withstand greater external pressure and effectively preventing deformation and cracking under high-load conditions. Furthermore, the addition of additives such as toughening agents, antioxidants, and UV absorbers improves the toughness, aging resistance, and weather resistance of the PP manhole, extending its service life.

[0029] In addition, this embodiment improves the efficiency of injection molding and the stability of product quality through optimized processing technology and mold design, shortens the manufacturing cycle, reduces production costs, and is conducive to large-scale industrial production.

[0030] Example 2 This embodiment further discloses a structure of a twin-screw extruder based on embodiment 1; In this embodiment, the twin-screw extruder includes: a body, a feed bin 5, two screws 6, a drive mechanism 7, five sets of heating mechanisms, five sets of temperature sensors, and a circuit control device; See also Figure 1 The machine body includes a frame, a material collecting seat 1 and five cylinders 2 connected in sequence along the axial direction. The material collecting seat 1 and the five cylinders 2 are all installed on the frame. The structures of the five cylinders 2 can be the same or different. Each cylinder 2 has a through groove running through the two end faces. The ends of two adjacent cylinders 2 are connected to each other. The connection method can be welding or detachable connection. Please refer to Figure 3 When the structures of the five cylinders 2 are different, such as different diameters, two adjacent cylinders 2 can be connected and transitioned by a connecting cylinder 9 to achieve a smooth transition between the adjacent cylinders 2; a machine head 3 is provided on the cylinder 2 away from the collecting seat 1, and a flow channel 4 is provided in the collecting seat 1. The flow channel 4 is connected to the through grooves on the five cylinders 2 and is connected to the machine head 3. The flow channel 4 is for the melt to flow; The feed bin 5 is provided on the collecting seat 1 and is connected to the flow channel 4. The mixed materials can be introduced into one end of the flow channel 4 through the feed bin 5. Two screws 6 are arranged in parallel in the flow channel 4. The two screws 6 are distributed axially on the entire flow channel 4. One end of the two screws 6 passes through the side wall of the aggregate seat 1 and extends to the outside of the aggregate seat 1. Figure 1 The two screws 6 shown in FIG. 6 overlap, so only the closer one can be seen; The driving mechanism 7 can drive the two screws 6 to rotate in the same direction or in opposite directions. Any structure in the prior art that can achieve this driving function can be used as the driving mechanism 7 in this embodiment. Specifically, the driving mechanism 7 includes a motor, a reducer, a driving gear, a driven gear and a transmission gear set. The driving gear and the driven gear are respectively provided on the two screws 6. The transmission gear set is used to connect the driving gear and the driven gear. The motor is connected to one screw 6 through the reducer to rotate the screw 6. At this time, the screw 6 drives the other screw 6 to rotate through the cooperation of the driving gear, the transmission gear set and the driven gear; the transmission gear set is detachably connected to the driving gear and the driven gear, and the transmission gear set can have a reversing function to realize the same or opposite rotation of the two screws 6; Five groups of heating mechanisms are respectively arranged inside the five cylinders 2, and the heating mechanisms can heat the inside of the corresponding cylinders 2. The heating mechanisms can adopt heating structures such as resistance heating, electromagnetic induction heating, etc. in the prior art; For details, please refer to Figure 1 and Figure 2 The inner wall surface of the cylinder 2 can be nitrided to improve the high temperature resistance and wear resistance of the inner wall of the cylinder 2; a mounting ring groove 201 is provided on the inner wall of the cylinder 2, and the cross section of the mounting ring groove 201 is U-shaped, and a heating mechanism can be installed in the mounting ring groove 201; The heating mechanism includes a heat insulating layer 801, a resistance wire 802 and a heat conductive cover 803. The resistance wire 802 can be made of nickel-chromium alloy and is spirally distributed in the mounting ring groove 201. The bottom surface of the mounting ring groove 201 can be provided with a positioning protrusion to prevent the resistance wire 802 from moving. The heat-conducting cover 803 is provided at the notch of the mounting ring groove 201 for sealing the resistance wire 802. The heat-conducting cover 803 can be made of copper alloy and can be fixed to the edge of the mounting ring groove 201 by bolts. The heat insulation layer 801 is arranged on the side of the resistance wire 802 away from the heat conductive cover 803. The heat insulation layer 801 can be designed as a double-layer structure, with the inner layer being ceramic fiber felt and the outer layer being wrapped with stainless steel foil (to reflect radiant heat). It is fixed to the bottom of the mounting ring groove 201 by a clamp; Five groups of temperature sensors are respectively arranged inside the five cylinders 2, and the temperature sensors can monitor the temperature inside the corresponding cylinders 2 in real time; Specifically, the temperature sensor is fixed to the inner wall of the cylinder 2 by a thread. The temperature sensor can be a PT100 platinum resistor, such as Honeywell HEL-705-T. Thermal conductive silicone grease can be applied to the head of the sensor to improve the response speed of the sensor. In this embodiment, the circuit control device can be a PLC control system or a DSC control system. The circuit control device can respectively control the driving mechanism 7, the five groups of heating mechanisms, and the five groups of temperature sensors; specifically, the circuit control device controls the driving direction and driving speed of the driving mechanism 7; one group of temperature sensors corresponds to one group of heating mechanisms, and the circuit control device controls the heating mechanisms to heat the inside of the corresponding cylinder 2. During this process, the temperature sensor monitors the temperature inside the cylinder 2 in real time and feeds the temperature value back to the circuit control device. At this time, the circuit control device controls the heating mechanism to heat or stop according to the current temperature value inside the cylinder 2, thereby realizing temperature closed-loop control and ensuring that the inside of the corresponding cylinder 2 reaches the required temperature; the five groups of heating mechanisms and the five groups of temperature sensors do not interfere with each other; The twin-screw extruder of this embodiment realizes stepped temperature control, improves the uniformity of the melt, and improves the uniformity of fiber dispersion.

[0031] Example 3 This embodiment provides a high-load PP inspection well, which is manufactured by the manufacturing method of embodiment 1 and / or embodiment 2, so that the inspection well has a high load-bearing capacity and good comprehensive performance. In addition, please refer to Figure 4 The inspection well of this embodiment includes a wellbore 10, and reinforcing ribs 11 are provided on the outer wall of the wellbore 10. The reinforcing ribs 11 are distributed in a spiral shape, which can significantly improve the axial bearing capacity of the wellbore 10 and improve the lateral pressure capacity of the soil.

[0032] The embodiments of the present invention are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for manufacturing a high-load PP inspection well, characterized in that: include: Raw material configuration: PP resin with a melt flow rate ≥10g / 10min (190℃, 2.16kg) and a tensile yield strength ≥45MPa is used as the base material, with 15%-30% glass fiber (length 3mm-6mm), 5%-10% POE toughening agent, 0.2%-0.3% hindered phenol antioxidant and 0.3%-0.5% benzophenone UV absorber added; Mixing and granulation: Mix at 180-220℃ at 500-800r / min for 10-35 minutes, melt granulate through twin-screw extruder, extrusion temperature 180-225℃; Injection molding: The granulated material is injected into the mold cavity through the injection molding machine at an injection temperature of 180-230℃, a pressure of 70-90MPa, and an injection speed of 40cm³ / s-60cm³ / s. After the injection is completed, the pressure is maintained at 70%-90% of the injection pressure for 15-20s, and then cooled and demolded.

2. The method for manufacturing a high-load PP inspection well according to claim 1, characterized in that: The extrusion process of the twin-screw extruder is divided into multiple temperature zones, wherein the first zone is 180°C-190°C, the second zone is 190°C-200°C, the third zone is 200°C-210°C, the fourth zone is 210°C-220°C, the fifth zone is 215°C-225°C, and the head (3) temperature is 215°C-225°C.

3. The method for manufacturing a high-load PP inspection well according to claim 2, characterized in that: The twin-screw extruder comprises: A machine body, comprising a material collecting seat (1) and five cylinders (2) connected in sequence along the axial direction, a machine head (3) being provided on the cylinder (2) away from the material collecting seat (1), a flow channel (4) being provided in the material collecting seat (1), the flow channel (4) passing through the five cylinders (2) and then communicating with the machine head (3); A feed bin (5), the feed bin (5) being arranged on the material collecting seat (1), and the feed bin (5) being connected to the flow channel (4); Two screw rods (6), the two screw rods (6) are arranged in parallel in the flow channel (4), the two screw rods (6) are distributed axially on the entire flow channel (4), and one end of the two screw rods (6) passes through the side wall of the material collection seat (1) and extends to the outside of the material collection seat (1); A driving mechanism (7), wherein the driving mechanism (7) is used to drive the two screw rods (6) to rotate; Five groups of heating mechanisms, the five groups of heating mechanisms being respectively arranged inside the five cylinders (2), and the heating mechanisms being capable of heating the inside of the corresponding cylinders (2); Five groups of temperature sensors, the five groups of temperature sensors being respectively arranged inside the five cylinders (2), and the temperature sensors being capable of monitoring the temperature inside the corresponding cylinders (2) in real time; A circuit control device is provided, wherein the circuit control device can respectively control the driving mechanism (7), the five groups of heating mechanisms, and the five groups of temperature sensors.

4. The method for manufacturing a high-load PP inspection well according to claim 3, characterized in that: A mounting annular groove (201) is provided on the inner wall of the cylinder (2); the heating mechanism comprises a heat insulating layer (801), a resistance wire (802) and a heat conductive cover (803); the resistance wire (802) is spirally distributed in the mounting annular groove (201); the heat conductive cover (803) is provided at a notch of the mounting annular groove (201) for sealing the resistance wire (802); and the heat insulating layer (801) is provided on a side of the resistance wire (802) away from the heat conductive cover (803).

5. The method for manufacturing a high-load PP inspection well according to claim 3, characterized in that: The driving mechanism (7) comprises a motor, a reducer, a driving gear, a driven gear and a transmission gear set. The driving gear and the driven gear are respectively arranged on two of the screw rods (6). The transmission gear set is used to connect the driving gear with the driven gear. The motor is connected to one of the screw rods (6) via the reducer.

6. The method for manufacturing a high-load PP inspection well according to claim 1, characterized in that: The injection molding machine is divided into multiple temperature zones, including a feeding zone of 180°C-190°C, a compression zone of 200°C-210°C, a melting zone of 210°C-220°C, a homogenizing zone of 220°C-230°C, and a nozzle temperature of 200°C-210°C.

7. A high-load PP inspection well, manufactured by the manufacturing method according to any one of claims 1 to 6, characterized in that: The inspection well comprises a wellbore (10), and reinforcing ribs (11) are provided on the outer wall of the wellbore (10), and the reinforcing ribs (11) are distributed in a spiral shape.

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