WO2022021487A1

WO2022021487A1 - Manufacturing method for high-rigidity pe pipeline

Info

Publication number: WO2022021487A1
Application number: PCT/CN2020/109461
Authority: WO
Inventors: 李挺; 张伟娇; 洪义华; 谷新剑; 洪伟武; 陈平; 宋荣浩
Original assignee: 临海伟星新型建材有限公司
Priority date: 2020-07-31
Filing date: 2020-08-17
Publication date: 2022-02-03
Also published as: CN111890653A

Abstract

Disclosed a manufacturing method for a high-rigidity PE pipeline, comprising the following steps: 1) a raw material is plasticized and extruded by means of an extruder to form a pipe blank; 2) the pipe blank enters a vacuum sizing box by means of a sizing sleeve; 3) cooling water is sprayed to cool the pipe blank in the vacuum sizing box; 4) the pipe blank is taken out of the vacuum sizing box to form a pipe; 5) the pipe enters a heat treatment apparatus (1), and the outer surface layer of the pipe is heated by means of the heat treatment apparatus (1); 6) the pipe enters a heat insulation apparatus (2) and is slowly cooled to be 60°C or below by means of the heat insulation apparatus (2); 7) the pipe enters a spraying box and is cooled by means of the spraying box; and 8) traction cutting is performed. By means of a fractional crystallization method, the crystallinity of the inner wall layer of the PE pipeline is first improved, and then the outer surface layer of the pipeline is recrystallized, thereby eliminating residual stress, and improving the rigidity of the PE pipeline.

Description

A kind of manufacturing method of high rigidity PE pipe

technical field

The invention relates to the technical field of PE pipe material manufacturing, in particular to a method for manufacturing a high-rigidity PE pipe.

Background technique

When PE pipes are used for drainage, the wall thickness is generally thin. The standard size table is generally SDR21, SDR26, and SDR33. When they are used for siphon drainage and vacuum drainage, the pipeline should be subjected to vacuum negative pressure. When the rigidity of the pipe ring is insufficient, There will be pipe flattening. At present, the extrusion of PE pipes at home and abroad all use cooling water for shaping production. The ability to control the crystallinity of the PE material is weak, the crystallinity of the product is not high, and a large residual stress is formed during the rapid cooling and shaping process of the product. It belongs to high crystallinity plastic, and its crystallinity has a significant effect on the rigidity of the product.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the prior art, the present invention provides a high-rigidity PE pipe manufacturing method with reasonable structural design.

The technical scheme of the present invention is as follows:

A method for manufacturing a high-rigidity PE pipe, comprising the steps of:

1) The raw material is plasticized and extruded through an extruder to form a tube embryo;

2) The tube blank enters the vacuum sizing box through the sizing sleeve;

3) The tube blank is cooled by cooling water spray in the vacuum sizing box;

4) The tube embryo comes out of the vacuum sizing box to form a tube;

5) The pipe enters the heat treatment device, and the outer layer of the pipe is heated by the heat treatment device;

6) The pipe enters the heat preservation device, and is slowly cooled to below 60 ℃ through the heat preservation device;

7) The pipe enters the spray box and is cooled by the spray box;

8) Traction cutting.

The method for manufacturing a high-rigidity PE pipe is characterized in that, in the step 3), the water temperature in the vacuum sizing box is maintained at 40°C-60°C, and the surface temperature of the tube blank is controlled at 80℃-100℃.

The method for manufacturing a high-rigidity PE pipe is characterized in that, in the step 5), the temperature adjustment range of the heat treatment device is 120°C-150°C, and the temperature of the outer surface of the pipe when the heat treatment device is discharged is controlled at 120°C-150°C .

The method for manufacturing a high-rigidity PE pipe is characterized in that the heat treatment device in step 5) is a hollow structure, including a heat treatment drying tunnel, and the heat treatment drying tunnel is uniformly provided with a group of heating pipes along the circumferential direction of its inner cavity, The heat treatment drying tunnel is provided with iron sheets with holes along the circumferential direction of its inner cavity, and the iron sheets are located between the heating pipe and the heat treatment drying tunnel, so that a hot air circulation channel is formed between the iron sheets and the heat treatment drying tunnel. A hot air outlet is provided above the hot air circulation channel, and a hot air inlet is provided below it.

The method for manufacturing a high-rigidity PE pipe is characterized in that the two ends of the heat treatment drying tunnel are respectively provided with first gaskets, which are used for sealing the joints of the heat treatment drying tunnel.

The method for manufacturing a high-rigidity PE pipe is characterized in that the length of the heat treatment drying tunnel is 50-150 cm, and the heating pipe is an infrared heating pipe.

The method for manufacturing a high-rigidity PE pipe is characterized in that a temperature sensor is provided on one side of the heat treatment drying tunnel, the temperature sensor is an infrared temperature sensor, and a temperature controller is connected to the temperature sensor.

The method for manufacturing a high-rigidity PE pipe is characterized in that the two ends of the heating pipe are respectively provided with a heating pipe base, and the heating pipe is fixed to the heat treatment drying tunnel through the heating pipe base.

The method for manufacturing a high-rigidity PE pipe is characterized in that, in the step 6), the thermal insulation device includes a set of thermal insulation units, wherein each thermal insulation unit adopts a sealed box body, and two ends of the thermal insulation unit are respectively provided with a set of thermal insulation units. There is a gasket, and the second gasket is used for sealing between two adjacent insulation units.

The method for manufacturing a high-rigidity PE pipe is characterized in that a heat dissipation hole is provided above the heat preservation unit, and a flip cover is provided on the heat dissipation hole.

The beneficial effects of the present invention are as follows: through the method of fractional crystallization, it first increases the crystallinity of the inner wall layer of the PE pipe, and then recrystallizes the outer layer of the pipe to eliminate residual stress, and finally significantly improves the rigidity of the PE pipe.

Description of drawings

Fig. 1 is the structure schematic diagram of the heat treatment device of the present invention;

Fig. 2 is the structure schematic diagram of the thermal insulation device of the present invention;

Fig. 3 is the front view structure schematic diagram of the heat treatment device of the present invention;

FIG. 4 is a schematic side view of the structure of the heat treatment apparatus of the present invention.

In the figure: 1-heat treatment device; 101-hot air circulation channel; 102-first gasket; 103-heating pipe; 104-temperature sensor; 105-thermostat; 106-hot air inlet; 107-hot air outlet; 108-iron sheet; 109-heat treatment drying tunnel; 2-insulation device; 201-insulation unit.

detailed description

The present invention will be further described below with reference to the accompanying drawings and embodiments.

The technological process of the present invention is as follows: 1. Plasticizing and extruding raw materials → 2. The tube blank enters the vacuum sizing box through the sizing sleeve → 3. The tube blank is sprayed and cooled by cooling water in the vacuum sizing box → 4. The vacuum is released Sizing box → 5. Enter the heat treatment device to heat the outer layer of the pipe → 6. Enter the insulation device to cool slowly → 7. Cool through the spray box → 8. Pull and cut.

The main difference between the process of the present invention and the traditional process is: temperature control is performed on the cooling of the process 3, and the outer layer heating of the process 5 and the heat preservation device of the process 6 are added for slow cooling.

Process 3 requires adjusting the water temperature of the vacuum sizing box. According to the wall thickness of the pipeline and the production speed, the water temperature in the vacuum sizing box is required to be kept at 40℃-60℃, so that the surface temperature of the PE pipe is controlled at 80℃ when it leaves the vacuum sizing box. -100℃. Through the temperature control of process 3, on the one hand, the product size can be fixed, on the other hand, it is beneficial to reduce the influence of the cooling of the outer surface layer of the pipeline on the inner wall layer, and shorten the heating time of the outer surface layer of the pipeline in process 5, and at the same time improve the crystallinity of the inner wall of the pipeline. , the outer layer of the traditional pipe will be rapidly cooled by cooling water when passing through steps 2 and 3, the crystallinity is low, and there is residual stress.

As shown in Figures 1, 3, and 4, the process 5 uses a heat treatment device to heat the outer layer of the pipe. The heat treatment device has a temperature-controlled channel of a certain length. The suitable length of the channel is 50cm-150cm, and the optimal temperature adjustment range includes 120℃- 150°C. The heat treatment device is equipped with a temperature detector and a temperature controller, which are used to detect the temperature of the outer surface of the pipeline at the moment of exiting the heat treatment device, and to control the temperature after heating to be within the set range. The optimal temperature of the outer surface layer when the pipeline exits the heat treatment device is controlled at 120℃-150℃.

The heat treatment device includes a heat treatment drying tunnel 109. The length of the inner cavity of the heat treatment drying tunnel 109 of the heat treatment device is 50-150 cm. The two ends of the heat treatment drying tunnel 109 are respectively provided with first gaskets 102. The first gasket 102 in this embodiment can be disassembled. , which is convenient for maintenance and replacement. The first gasket 102 provided in the present invention is mainly used to reduce the air circulation on both sides of the heating mechanism 1 to prevent heat loss.

The heat treatment drying tunnel 109 is uniformly provided with a group of heating pipes 103 along the circumferential direction of its inner cavity. The two ends of the heating pipes 103 are respectively provided with heating pipe bases, and the heating pipes 103 are fixed to the heat treatment drying tunnel 109 through the heating pipe bases. The heating tube 103 in is an infrared heating tube.

The heat treatment drying tunnel 109 is provided with an iron sheet 108 with holes along the circumferential direction of its inner cavity, and the iron sheet 108 is located between the heating pipe 103 and the heating mechanism body 109, and a hot air circulation channel is formed between the iron sheet 108 and the heating mechanism body 109 101. A hot air outlet 107 is arranged above the hot air circulation channel 101, and a hot air inlet 106 is arranged below it. The hot air inlet 106 of the hot air circulation channel 101 is connected to the hot air blower. The utility model makes the PE pipe heated evenly by the provided hot air blower.

There is a temperature sensor 104 on one side of the heat treatment drying tunnel 109, which is mainly used to measure the surface temperature of the PE pipeline at the moment of exiting the heating mechanism 1. The temperature sensor 104 is connected with the temperature controller 105. Feedback to the temperature controller 105, the temperature controller 105 quickly adjusts the temperature; the temperature sensor 104 is an infrared temperature sensor.

The outer layer of the pipeline is heated through the process 5, and the temperature of the outer layer can reach 120°C-150°C, so that the recrystallization occurs and the residual stress is eliminated. The heating time of the outer layer by this method only needs to last 10s-30s. The traditional pipeline cooling and then heat treatment generally takes 1h-3h.

As shown in Fig. 2, in step 6, the pipeline is kept warm by the thermal insulation device, which is slowly cooled. The thermal insulation device is generally composed of multi-section thermal insulation units.

The heat preservation device includes a set of heat preservation units 201, the number of heat preservation units 201 is at least 3, the length of the heat preservation unit is 6m, each heat preservation unit 201 is a sealed stainless steel water tank or pipe, and the two ends of the heat preservation unit 201 are respectively provided with second The space between two adjacent insulation units 201 is sealed by a second gasket. In this embodiment, a heat dissipation hole is provided above the insulation unit 201, and a flip cover is provided on the heat dissipation hole, and the flip cover is opened or closed to adjust the heat preservation. The temperature in the unit 201, the second gasket provided in the present invention is mainly to reduce the air circulation inside the box and improve the heat preservation effect.

Through the heat preservation device in step 6, the heated outer layer and inner wall layer of the pipeline are slowly cooled to improve the crystallinity and reduce the residual stress.

Example 1:

2) The tube blank enters the vacuum sizing box through the sizing sleeve;

3) The tube blank is cooled by cooling water spray in the vacuum sizing box, and the water temperature in the vacuum sizing box is kept at 40°C, so that the surface temperature of the tube blank is controlled at 80°C when it leaves the vacuum sizing box;

4) The tube embryo comes out of the vacuum sizing box to form a tube;

5) The pipe enters the heat treatment device, and the outer layer of the pipe is heated by the heat treatment device; the temperature adjustment range of the heat treatment device is 120°C, and the temperature of the outer layer of the pipe when it leaves the heat treatment device is controlled at 120°C;

6) The pipe enters the heat preservation device, and is slowly cooled to below 60°C (normal temperature) through the heat preservation device;

7) The pipe enters the spray box and is cooled by the spray box;

8) Traction cutting.

Example 2:

2) The tube blank enters the vacuum sizing box through the sizing sleeve;

3) The tube blank is cooled by cooling water spray in the vacuum sizing box, and the water temperature in the vacuum sizing box is kept at 60°C, so that the surface temperature of the tube blank is controlled at 100°C when it leaves the vacuum sizing box;

4) The tube embryo comes out of the vacuum sizing box to form a tube;

5) The pipe enters the heat treatment device, and the outer surface of the pipe is heated by the heat treatment device; the temperature adjustment range of the heat treatment device is 150 °C, and the outer surface temperature of the tube when it exits the heat treatment device is controlled at 150 °C;

7) The pipe enters the spray box and is cooled by the spray box;

8) Traction cutting.

Example 3:

2) The tube blank enters the vacuum sizing box through the sizing sleeve;

3) The tube blank is cooled by cooling water spray in the vacuum sizing box, and the water temperature in the vacuum sizing box is kept at 45°C, so that the surface temperature of the tube blank is controlled at 85°C when it leaves the vacuum sizing box;

4) The tube embryo comes out of the vacuum sizing box to form a tube;

5) The pipe enters the heat treatment device, and the outer surface of the pipe is heated by the heat treatment device; the temperature adjustment range of the heat treatment device is 130 °C, and the outer surface temperature of the tube when it exits the heat treatment device is controlled at 130 °C;

7) The pipe enters the spray box and is cooled by the spray box;

8) Traction cutting.

By increasing the control of the above three processes, the raw material of the inner wall layer of the PE pipe can be kept at a relatively high temperature and fully naturally crystallized to avoid crystallization defects and crystallinity reduction caused by rapid cooling. Compared with the traditional process, the crystallinity of the inner wall layer of the pipeline is improved. DSC (differential scanning calorimeter) was used to measure and calculate the crystallinity of the inner wall layer of the PE100 pipe of dn110×en4.2 SDR26. Under this method, the crystallinity of the inner wall layer PE100 was 75%, and the crystallinity of the inner wall layer PE100 under the conventional process was 60%. %, the crystallinity of this method is improved by 25% in the conventional process.

After the outer layer of the pipe is heated and slowly cooled, its crystallinity is significantly improved compared with the traditional process. Taking the PE100 pipe of dn110×en4.2SDR26 as an example, measured and calculated by DSC, the crystallinity of the outer layer PE100 under this method is 78%, and the crystallinity of the outer layer PE100 under the conventional process is 53%. The improvement is 47%.

The rigidity of the PE100 pipe ring prepared by this technology is obviously improved. Taking the dn110×en4.2 SDR26 product as an example, the ring rigidity is 8.1KN/m2, and the typical value of the pipe ring rigidity prepared by the traditional process is 6.7KN/m2. The increase in ring stiffness on the conventional process is 21%.

By improving the crystallinity of the PE pipe and eliminating the residual stress, this technology can also reduce the longitudinal shrinkage rate of the pipe, reduce the influence of the environmental temperature change on the length change of the pipe, and improve the dimensional stability of the pipe. The principle is the same as that of improving the ring stiffness of the pipe. . The comparative data of longitudinal shrinkage and dimensional change are as follows:

project	Test conditions	this technology	conventional process
vertical yield	Oven 110℃, 1h	0.8%	1.0%
size change	Raised by 30℃, measure the ratio of length change	0.3%	0.4%

.

Claims

A method for manufacturing a high-rigidity PE pipe, comprising the steps of:

1) The raw material is plasticized and extruded through an extruder to form a tube embryo;

2) The tube blank enters the vacuum sizing box through the sizing sleeve;

3) The tube blank is cooled by cooling water spray in the vacuum sizing box;

4) The tube embryo comes out of the vacuum sizing box to form a tube;

5) The pipe enters the heat treatment device, and the outer layer of the pipe is heated by the heat treatment device;

6) The pipe enters the heat preservation device, and is slowly cooled to below 60 ℃ through the heat preservation device;

7) The pipe enters the spray box and is cooled by the spray box;

8) Traction cutting.
The method for manufacturing a high-rigidity PE pipe according to claim 1, characterized in that in step 3), the water temperature in the vacuum sizing box is maintained at 40°C-60°C, so that the tube blank is kept in the vacuum sizing box when it exits the vacuum sizing box. Its surface temperature is controlled at 80℃-100℃.
The method for manufacturing a high-rigidity PE pipe according to claim 1, wherein in the step 5), the temperature adjustment range of the heat treatment device is 120°C-150°C, and the temperature of the outer layer of the pipe when the heat treatment device is discharged is controlled at 120°C. ℃-150℃.
The method for manufacturing a high-rigidity PE pipe according to claim 1, wherein the heat treatment device in step 5) is a hollow structure, comprising a heat treatment drying tunnel (109), and the heat treatment drying tunnel (109) extends along the inner surface of the heat treatment tunnel (109). A group of heating pipes (103) are evenly arranged in the circumferential direction of the cavity, and the heat treatment drying tunnel (109) is provided with iron sheets (108) with holes along the circumferential direction of the inner cavity, and the iron sheets (108) are located in the heating pipes (103). ) and the heat treatment drying tunnel (109), thereby forming a hot air circulation channel (101) between the iron sheet (108) and the heat treatment drying tunnel (109), and a hot air outlet (107) is provided above the hot air circulation channel (101). ), and there is a hot air inlet (106) below it.
The method for manufacturing a high-rigidity PE pipe according to claim 1, wherein first gaskets (102) are respectively provided at both ends of the heat treatment drying tunnel (109) for connecting the heat treatment drying tunnel (109). seal at the place.
The method for manufacturing a high-rigidity PE pipe according to claim 1, wherein the heat treatment drying tunnel (109) has a length of 50-150 cm, and the heating pipe (103) is an infrared heating pipe.
The method for manufacturing a high-rigidity PE pipe according to claim 1, wherein a temperature sensor (104) is provided on one side of the heat treatment drying tunnel (109), and the temperature sensor (104) is an infrared temperature sensor , a temperature controller (105) is connected to the temperature sensor (104).
The method for manufacturing a high-rigidity PE pipe according to claim 1, characterized in that, both ends of the heating pipe (103) are respectively provided with a heating pipe base, and the heating pipe (103) is fixed by the heating pipe base In the heat treatment drying tunnel (109).
The method for manufacturing a high-rigidity PE pipe according to claim 1, characterized in that, in the step 6), the thermal insulation device comprises a set of thermal insulation units (201), wherein each thermal insulation unit (201) adopts a sealed box body The two ends of the insulation unit (201) are respectively provided with gaskets, and the second gasket is used for sealing between two adjacent insulation units (201).
The method for manufacturing a high-rigidity PE pipe according to claim 9, characterized in that a heat dissipation hole is provided above the heat preservation unit (201), and a flip cover is provided on the heat dissipation hole.