Vacuum cooling device suitable for PPR small pipe diameter pipe and cooling process thereof

Abstract

The application discloses a vacuum cooling device suitable for PPR small pipe diameter pipes and a cooling process thereof, and the device comprises a sizing sleeve, a vacuum cooling box, a water segregator, a refrigerator and a water pump; a supporting structure for supporting the pipes is arranged in the vacuum cooling box; a stainless steel pipe is arranged at a predetermined position below the pipes; one end of the stainless steel pipe is sealed, and the other end is communicated with a first outlet of the water segregator; fan-shaped nozzles are uniformly arranged on the stainless steel pipe at predetermined intervals; and the fan-shaped nozzles are arranged with their openings facing the pipes. A water pump and a water pressure control valve are further arranged on a connecting pipeline between the first outlet of the water segregator and the stainless steel pipe. The cooling process of pipe soaking + spraying is arranged, the pipes are more uniformly cooled around, the fan-shaped water flow is formed through the spraying process, the bubbles on the surface of the pipes are effectively removed, the phenomenon of pits, concaves and convexes on the surface of the products is prevented, the ovality effect of the products is better, and the product quality is obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of pipe manufacturing technology, specifically relating to a vacuum cooling device and its cooling process suitable for small-diameter PPR pipes. Background Technology

[0002] In the pipe manufacturing process, the vacuum sizing process is a crucial step that significantly impacts the quality of the pipe. The melt is extruded from the extruder, passes through a sizing sleeve, and reaches a vacuum cooling tank. Under a certain vacuum level and with appropriate support, the pipe is shaped, cooled, and sizing to meet appearance and dimensional requirements, thus solidifying into a pipe within the vacuum cooling tank.

[0003] The PPR pipe manufacturing process is as follows: After the raw material enters the screw barrel, it is heated and plasticized. Extrusion molding is achieved by using the squeezing action of the screw or plunger to force the heated and molten plastic through the die under pressure. At this point, the preform is soft and at a high temperature. The preform is bonded to the pipe end by traction. Pre-cooling with chilled water ensures the preform smoothly enters the sizing sleeve. The expansion coefficient is adjusted, and the speed is increased to within the process control range. The water ring is then adjusted to the appropriate position. Immediately after the molten pipe blank leaves the sizing sleeve, the outer side of the pipe has solidified, but most of the pipe wall material remains molten. The greater the pipe wall thickness and the higher the extrusion output, the greater the ratio of molten material on the inner side of the pipe wall to the solidified layer on the outer side at the end of the sizing equipment. This increases the likelihood of elliptical deformation and unevenness on the outer surface of the pipe. Possible causes of elliptical deformation and unevenness on the outer surface include:

[0004] (1) The force between the pipe and the guide device in the cooling tank (the support roller, support plate and sizing sleeve are not horizontal).

[0005] (2) Gravity effect, the effect of spray atomization around the product on the cooling of the product surface;

[0006] (3) Uneven cooling of the material around the pipe causes shrinkage. (Spraying, uneven cooling)

[0007] In addition, cooling water will generate bubbles under vacuum and pressure conditions, which will adhere to the surrounding area of ​​the pipe. The bursting of these bubbles will also have an adverse effect on the surface morphology of the pipe.

[0008] Therefore, it is necessary to improve and upgrade the existing vacuum cooling process to solve the above-mentioned technical problems in the existing preparation process. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a vacuum cooling device and cooling process suitable for small-diameter PPR pipes, solving the technical problems existing in the current manufacturing process.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A vacuum cooling device suitable for small-diameter PPR pipes includes a sizing sleeve, a vacuum cooling box, a water distributor, a chiller, and a water pump. The sizing sleeve and the vacuum cooling box are fixedly connected and internally interconnected. A passage for the pipe to pass through is provided inside the sizing sleeve and the vacuum cooling box. A support structure is provided inside the vacuum cooling box to support the pipe. A stainless steel pipe is installed at a predetermined position below the pipe. One end of the stainless steel pipe is sealed, and the other end extends outside the vacuum cooling box and communicates with the first outlet of the water distributor. Several openings are evenly arranged at predetermined intervals on the stainless steel pipe. A special connector is welded to each opening. A fan-shaped nozzle is installed on the special connector, and the opening of the fan-shaped nozzle faces the pipe.

[0012] The fan-shaped nozzle opening is arranged in a cross shape with the pipe installation direction.

[0013] The second outlet of the water distributor is connected to the inside of the sizing sleeve; the inlet and outlet of the water distributor are respectively connected to the inlet and outlet of the chiller.

[0014] A water pump and a water pressure control valve are also installed on the connecting pipeline between the first outlet of the water distributor and the stainless steel pipe. The water pump is used to provide the inlet water pressure, and the water pressure control valve is used to control the water pressure inside the stainless steel pipe.

[0015] The support structure includes several parallel flanges and a bracket that passes through the flanges. The bracket is fixed inside the vacuum cooling box and is used to fix the flanges. The flanges have through holes in the middle for pipes to pass through.

[0016] A water level control box is connected to the outside of the vacuum cooling box, and the internal water level is adjusted by feedback from the internal floating ball valve.

[0017] The vacuum cooling chamber is integrally formed inside; the opening angle of the fan-shaped nozzle is 105-115 degrees, preferably 110 degrees.

[0018] The stainless steel pipe is positioned 2-3 cm below the pipe material and is positioned in the vacuum cooling box by a positioning frame.

[0019] This invention also proposes a vacuum cooling process suitable for small-diameter PPR pipes, using the vacuum cooling device described above, and the process is as follows:

[0020] The vacuum cooling chamber is evacuated, the chiller temperature is set, and then the water inlet and water pump of the distributor are started. Water flows through the chiller to the preset temperature and then flows out from the first and second outlets of the distributor. The second outlet pipe is connected to the inside of the sizing sleeve, so that the through cavity between the sizing sleeve and the inside of the vacuum cooling chamber is filled with water. The first outlet pipe is filled with water by the water pump, and the water pressure is controlled to the set pressure value by the water pressure control valve. When the pipe is pulled into the vacuum cooling chamber, the pipe is immersed in the cooling water inside the vacuum cooling chamber, and at the same time, the pipe is sprayed with water through the fan-shaped nozzles to achieve the effect of immersion and spraying.

[0021] The technical solution of this invention has the following beneficial effects:

[0022] (1) This invention changes the process of vacuum box spraying to pipe immersion, and at the same time as the immersion process, it achieves more uniform cooling around the pipe by spraying the pipe with a fan-shaped nozzle. The fan-shaped water flow is formed by the spraying process. Combined with the optimal fan-shaped nozzle angle of 105-115 degrees, it can effectively remove air bubbles on the surface of the pipe and prevent the product surface from being uneven during the production process, thereby making the product elliptic effect better and significantly improving the product quality.

[0023] (2) By setting up a support structure to support the pipe, the pipe is set horizontally, which improves the levelness of the force between the pipe and the guide device in the vacuum cooling box;

[0024] (3) By changing the two chambers inside the vacuum cooling box into one continuous chamber, the water level inside the box can be kept consistent, and the operating cost of the equipment can be saved;

[0025] (4) Combine with an externally connected refrigeration unit to control the water temperature and ensure the dimensional stability of the product. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the vacuum cooling device for small-diameter PPR pipes according to the present invention.

[0027] Figure 2 The diagram shows the spray pattern of the fan-shaped nozzle at different angles.

[0028] In the diagram: 1. Sizing sleeve; 2. Vacuum cooling box; 3. Water distributor; 31. First outlet; 32. Second outlet; 4. Refrigeration unit; 5. Water pump; 6. Pipe; 7. Stainless steel pipe; 8. Fan-shaped nozzle; 9. Water pressure control valve; 10. Water level control box; 11. Flange; 12. Bracket. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] like Figure 1 As shown, a vacuum cooling device suitable for small-diameter PPR pipes includes a sizing sleeve 1, a vacuum cooling box 2, a water distributor 3, a chiller 4, and a water pump 5. The sizing sleeve 1 and the vacuum cooling box 2 are fixedly connected and internally interconnected. A passage for the pipe 6 to pass through is provided inside the sizing sleeve 1 and the vacuum cooling box 2. A support structure is provided inside the vacuum cooling box 2 to support the pipe 6. A stainless steel pipe 7 is provided at a predetermined position below the pipe 6. One end of the stainless steel pipe 7 is sealed, and the other end extends out of the vacuum cooling box 2 and communicates with the first outlet 31 of the water distributor 3. Several openings are evenly arranged at predetermined intervals on the stainless steel pipe 7. A special connector is welded to each opening. A fan-shaped nozzle 8 is installed on the special connector, and the opening of the fan-shaped nozzle 8 is facing the pipe 6.

[0031] The opening of the fan-shaped nozzle 8 is arranged in a cross shape with the pipe 6, which can increase the spraying effect of the nozzle water flow on the pipe.

[0032] The second outlet 32 ​​of the water distributor 3 is connected to the interior of the sizing sleeve 1; the inlet and outlet of the water distributor 3 are respectively connected to the inlet and outlet of the chiller 4. The set temperature of the cooling water is controlled by the chiller 4 to improve the uniformity of cooling.

[0033] A water pump 5 and a water pressure control valve 9 are also installed on the connecting pipeline between the first outlet 31 of the water distributor 3 and the stainless steel pipe 7. The water pump 5 is used to provide the inlet water pressure, and the water pressure control valve 9 is used to control the water pressure inside the stainless steel pipe 7. In actual production, the pressure inside the stainless steel pipe is generally controlled to be about 3 kg.

[0034] The support structure includes several parallel flanges 11 and a bracket 12 passing through the flanges. The bracket 12 is fixed inside the vacuum cooling box 2 and is used to fix the flanges 11. The flanges 11 have a through hole in the middle for the pipe 6 to pass through. The support structure improves the horizontality of the pipe traction.

[0035] A water level control box 10 is connected to the outside of the vacuum cooling box 2, and the internal water level is adjusted by feedback from the internal floating ball valve.

[0036] The vacuum cooling box 2 is integrally formed inside; the vacuum cooling box in the existing process has two chambers, but this application will cut the two chambers and connect them into one chamber, which can achieve a consistent water level inside the box, and can also reduce the number of equipment in operation and reduce costs.

[0037] The stainless steel pipe 7 is positioned 2-3 cm below the pipe 6 and is positioned in relation to the vacuum cooling box 2 via a positioning frame.

[0038] This invention also proposes a vacuum cooling process suitable for small-diameter PPR pipes, using the vacuum cooling device described above, and the process is as follows:

[0039] The vacuum cooling chamber 2 is evacuated, and the temperature of the refrigerator 4 is set (e.g., 2-3℃). Then, the water inlet of the water distributor 3 and the water pump 5 are started, so that the water flows through the refrigerator 4 to reach the preset temperature and then flows out from the first outlet 31 and the second outlet 32 ​​of the water distributor 3. The pipe of the second outlet 32 ​​is connected to the inside of the sizing sleeve 1, so that the through cavity inside the sizing sleeve 1 and the vacuum cooling chamber 2 is filled with water. The pipe of the first outlet 31 is filled with water under the action of the water pump 5, and the water pressure is controlled to the set pressure value by the water pressure control valve 9. When the pipe 6 is pulled into the vacuum cooling chamber, the pipe 6 is in the cooling water immersion mode inside the vacuum cooling chamber 2, and the pipe 6 is sprayed by the fan-shaped nozzle 8 to achieve the effect of immersion and spraying.

[0040] In summary, the embodiments of this application improve the existing cooling process by changing vacuum box spraying to immersion, thereby upgrading the cooling process for small-diameter PPR products.

[0041] 1. Install a stainless steel tube inside the vacuum cooling box. Make holes at 12 cm intervals along a straight line and weld special joints.

[0042] 2. Install a 110-degree fan-shaped de-aeration nozzle on the special connector, fix it in a cross shape with the pipe in a straight line, and combine it with a stainless steel concentric transition flange to assemble the flange support center.

[0043] 3. The other end of the stainless steel pipe is connected to the high-pressure chilled water and the chiller outlet. A water pressure control valve (stainless steel copper ball valve) is installed in the middle to control the internal water pressure of the deaerator (stainless steel pipe).

[0044] 4. A water level control box for the internal immersion water level is installed on the outside of the vacuum cooling box. The internal float valve can automatically adjust the level of the internal immersion water.

[0045] 5. The original two chambers inside the vacuum cooling chamber have been cut and connected to achieve a consistent water level inside the chamber. Combined with the externally connected refrigeration unit, water temperature is controlled to ensure the dimensional stability of the product during sizing.

[0046] 6. Through transformation, a single production line can operate with one water pump and one vacuum pump removed, achieving a reduction in power consumption.

[0047] Testing process:

[0048] Through relevant transformation, the testing process was started. In order to determine the optimal opening angle of the fan-shaped nozzle, fan-shaped de-bubbling nozzles with angles of 25 degrees, 45 degrees, 65 degrees, 80 degrees, 95 degrees, 105 degrees, 110 degrees, 115 degrees, and 120 degrees were used respectively. Under the condition of full immersion inside the vacuum cooling box, the water flow direction inside and the surface quality of the final pipe products were observed. The relevant results are shown in Table 1, and the spraying states of the fan-shaped nozzles at different angles are as Figure 2 shown (for some angles).

[0049] The results show that when the opening angle of the fan-shaped nozzle is 25 degrees, 45 degrees, 65 degrees, 80 degrees, or 95 degrees, there is a phenomenon of bubble adhesion around the pipe products, resulting in pitted and uneven surfaces of the products, which cannot be solved by adjusting the water temperature and the internal water pressure of the stainless steel pipe. Finally, only the fan-shaped nozzles with angles of 105 degrees, 110 degrees, and 115 degrees were observed. Under the condition of full immersion, the de-bubbling range can fully cover the periphery of the products, and the formed fan-shaped water flow can effectively remove the surface bubbles. There is no phenomenon of pitted and uneven surfaces during the production process. The production speed for small diameters can reach the range of the process card of the technical department, the ovality of the products is controlled within 10 silk (the original products were 25 silk), the surface quality is significantly improved, and the test results are qualified. When the angle is 120 degrees, due to the too large angle, it affects the surface quality of small-diameter products and cannot form an effective water flow, still causing the surface to be uneven. It can be seen that through experimental comparison and verification, the preferred opening angle of the fan-shaped nozzle is in the range of 105 - 115 degrees. Within the range of 105 - 115 degrees, usually the defoaming ratio reaches more than 98%, the basic profiles are fully defoamed, and there are very few small bubble problems, and their impact on the product surface can be ignored. The surface smoothness has reached the enterprise detection standard. When the opening angle is 110 degrees, no bubble bonding problem has been found yet, and the effect is the best.

[0050] Table 1 Influence of product surface quality verified at each angle

[0051]

[0052] Effect verification:

[0053] 1. All product qualities meet the control standards, and the test results are qualified.

[0054] 2. Through the transformation and upgrade of 13 production lines on site, the annual power consumption is reduced by about 360,000 yuan.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vacuum cooling device suitable for small-diameter PPR pipes, characterized in that, The system includes a sizing sleeve (1), a vacuum cooling box (2), a water distributor (3), a chiller (4), and a water pump (5). The sizing sleeve (1) and the vacuum cooling box (2) are fixedly connected and internally interconnected. A passage for the pipe (6) to pass through is provided inside the sizing sleeve (1) and the vacuum cooling box (2). A support structure is provided inside the vacuum cooling box (2) for supporting the pipe (6). A stainless steel pipe (7) is provided at a predetermined position below the pipe (6). One end of the stainless steel pipe (7) is sealed, and the other end extends out of the vacuum cooling box (2) and communicates with the first outlet (31) of the water distributor (3). Several openings are evenly provided on the stainless steel pipe (7) at predetermined intervals. A special connector is welded on each opening. A fan-shaped nozzle (8) is installed on the special connector. The opening of the fan-shaped nozzle (8) faces the pipe (6). The opening angle of the fan-shaped nozzle (8) is 105-115 degrees.

2. The vacuum cooling device for small-diameter PPR pipes according to claim 1, characterized in that, The opening direction of the fan-shaped nozzle (8) is arranged in a cross shape with the pipe (6).

3. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, The second outlet (32) of the water distributor (3) is connected to the inside of the sizing sleeve (1); the inlet and outlet of the water distributor (3) are connected to the inlet and outlet of the chiller (4), respectively.

4. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, A water pump (5) and a water pressure control valve (9) are also installed on the connecting pipeline between the first outlet (31) of the water distributor (3) and the stainless steel pipe (7). The water pump (5) is used to provide the inlet water pressure, and the water pressure control valve (9) is used to control the water pressure inside the stainless steel pipe (7).

5. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, The support structure includes several parallel flanges (11) and a bracket (12) that passes through the flanges (11). The bracket (12) is fixed inside the vacuum cooling box (2) and is used to fix the flanges (11). The flanges (11) have through holes in the middle for the pipes (6) to pass through.

6. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, A water level control box (10) is connected to the outside of the vacuum cooling box (2), and the water level inside is adjusted by feedback from the internal floating ball valve.

7. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, The interior of the vacuum cooling box (2) is integrally connected.

8. A vacuum cooling device suitable for small-diameter PPR pipes according to claim 1, characterized in that, The stainless steel pipe (7) is positioned 2-3 cm below the pipe (6) and is positioned with the vacuum cooling box (2) by a positioning frame.

9. A vacuum cooling process suitable for small-diameter PPR pipes, comprising using the vacuum cooling device as described in any one of claims 1-8, characterized in that, The process is as follows: The vacuum cooling box (2) is started to draw a vacuum, the temperature of the refrigeration unit (4) is set, and then the water inlet of the water distributor (3) and the water pump (5) are started, so that the water flows through the refrigeration unit (4) to reach the preset temperature and then flows out from the first outlet (31) and the second outlet (32) of the water distributor (3). The second outlet (32) pipe is connected to the inside of the sizing sleeve (1), so that the through cavity between the sizing sleeve (1) and the vacuum cooling box (2) is filled with water. The first outlet (31) pipe is filled with water in the stainless steel pipe (7) under the action of the water pump (5), and the water pressure is controlled to the set pressure value by the water pressure control valve (9). When the pipe (6) is pulled into the vacuum cooling box, the pipe (6) is in the cooling water immersion mode inside the vacuum cooling box (2), and the pipe (6) is sprayed by the fan-shaped nozzle (8) to achieve the effect of immersion plus spraying.

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