JP2010058364A - Apparatus for water-cooling hollow extruded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-cooling apparatus which can prevent occurrence of an irregular diameter change, a decline in roundness, bending, etc., before a hollow extruded article passes through water in water-cooling tank and is cooled/cured sufficiently and obtain the hollow extruded article high in dimensional accuracy. <P>SOLUTION: In the apparatus, an outsizing unit 2 is engaged with the molding entrance part of a decompressed water-cooling tank 1 which makes the hollow extruded article M extruded from an extruder E pass through water, and a cooling water circulating supply means in relation to the decompressed water-cooling tank 1 and a vacuum suction means for decompressing an air layer 10 in the decompressed water-cooling tank 1 are provided. The outsizing unit 2 is composed, so that a plurality of sizer members 20A-20H each having a sizing hole position the sizing hole centers on the same axis line to be arranged at prescribed intervals, and the hollow extruded article M, while being tensed by the air pressure of its hollow inside, is cooled with its outside diameter being contracted while passing in turn through the sizing holes of the sizer members 20A-20H. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water cooling apparatus for passing a hollow extruded product such as a synthetic resin pipe or a tube continuously extruded from an extruder in a substantially horizontal direction and allowing it to cool and cure.

  In general, in a production line for long extrudates, a water-cooled tank, a take-up machine, and a cutting machine are sequentially arranged downstream from the extruder, and the synthetic resin heated and melted by the extruder is discharged from the extruder. Extruded continuously in a substantially horizontal direction as a required cross-sectional shape through a die, and cooled and hardened by passing through the water in a water-cooled tank while taking out the high-temperature extrudate through the take-up machine, and predetermined with a cutting machine Cut into length and commercialize.

Since extruded products that are soft at high temperatures immediately after being extruded from the extruder are easily deformed by their own weight, generally, hollow extruded products such as pipes and tubes are hollowed out in the mandrel portion of the extruder. By sending a weak air pressure into the part, the internal pressure prevents the sag. Furthermore, for hollow extruded products, the inside of the water-cooled tank is reduced in pressure to suppress deformation due to water pressure, and a sizer is provided at the inlet of the water-cooled tank, and the extruded product is introduced into the water-cooled tank through the sizer. The outer shape is also regulated (Patent Document 1).
JP 61-35928 A

  However, with the spread of applications of extruded products in recent years, high dimensional accuracy of the order of 10 μm has been required as hollow extruded products such as synthetic resin pipes and tubes used especially for precision equipment and medical equipment. However, the hollow extruded product immediately after extrusion is more morphologically deformable than before, and in the conventional cooling method using a water-cooled tank, an irregular diameter change or In order to reduce the roundness, bend, etc., it is difficult to achieve the required high dimensional accuracy.

  In view of the above situation, the present invention is a water cooling device for a hollow extruded product, which has irregular diameter changes and roundness until the hollow extruded product is sufficiently cooled and cured in water in a water cooling tank. An object of the present invention is to provide a hollow extruded product with high dimensional accuracy that can prevent the occurrence of lowering, bending, etc., and can cope with recent demands.

  If the means for achieving the above object is shown with reference numerals in the drawings, the water cooling apparatus for hollow extruded products according to the invention of claim 1 is a hollow extruded continuously from the extruder E in a substantially horizontal direction. A reduced-pressure water-cooled tank 1 for allowing the extruded product M to pass through and cool is provided, and the outer shape of the hollow extruded product M introduced into the reduced-pressure water-cooled tank 1 is regulated at the molded product inlet of the reduced-pressure water-cooled tank 1. While the outsizing unit 2 is fitted, the cooling water circulation supply means for circulating the cooling water W into the reduced pressure water cooling tank 1 and the air layer 10 formed in the upper part of the reduced pressure water cooling tank 1 with a predetermined reduced pressure A vacuum suction means for setting the state, and the outsizing unit 2 has a plurality of sizer members 20A to 20H each having a sizing hole 21 through which the hollow extruded product M is inserted. 0A to 20H are arranged such that the centers of the sizing holes 21 are located on the same axis in the water in the reduced-pressure water cooling tank 1 and arranged at predetermined intervals, and the sizing holes of these sizer members 20A to 20H are reduced in diameter toward the rear side. The plurality of sizer members are maintained in a state where the hollow extruded product M extruded from the extruder E and passing through the reduced-pressure water-cooled tank 1 is stretched by the pressure inside the hollow. In the process of sequentially passing through the sizing holes 21 of 20A to 20H, the outer diameter is reduced and cooling is performed.

  According to a second aspect of the present invention, in the water cooling apparatus for a hollow extruded product according to the first aspect, the outsizing unit 2 has an inlet 22 for the hollow extruded product M, and the front end wall 1b of the vacuum water cooling tank 1 is provided. And a multi-stage sizing portion 2b which holds the plurality of sizer members 20A to 20H and is fixed to the inlet block portion 2a at the base end side. A cooling water passage 23 surrounding the entrance 22 is provided.

  According to a third aspect of the present invention, in the water-cooling device for a hollow extruded product according to the first or second aspect, the outsizing unit 2 includes the plurality of sizer members 20A each formed in a ring shape centered on the sizing hole 21. ˜20H is supported at the periphery by a plurality of support shafts 25 and arranged at a predetermined interval via spacers 24 between them, and is configured to be detachable from the support shafts 25. .

  According to a fourth aspect of the present invention, in the water-cooling device for a hollow extruded product according to any one of the first to third aspects, the sizer member 20H arranged at the tail projects from the substrate portion 20a to the inner back side of the reduced-pressure water-cooled tank 1. A central hole penetrating from the base plate portion 20a to the tip of the cylindrical portion 2b forms a sizing hole 21 and a large number of small holes 20c that penetrate the inside and outside of the entire cylindrical portion 20b. ... is formed.

  According to a fifth aspect of the present invention, in the water-cooling device for a hollow extruded product according to any one of the first to third aspects, the outsizing unit 2 is an entrance to the sanding portion (multistage sizing portion 2b) of the hollow extruded product M. The front bus part 2c which accommodates the cooling water W to the water level which the said entrance 22 immerses is provided in the outer side of 22 at least, The hollow extrusion molding M extruded from the extruder E passes the water of this front bus part 2c. Thus, it is configured to enter the reduced-pressure water cooling tank 1.

  According to a sixth aspect of the present invention, in the water cooling apparatus for a hollow extruded product according to the fifth aspect, the front bath portion 2c is configured such that the cooling water W introduced from a position closer to the bottom overflows and is discharged to the outside. In addition, an insertion guide member 27 having an insertion hole 27a for the hollow extruded product M at the front end is fitted in a detachable and replaceable manner.

  The effects of the present invention will be described below with reference numerals in the drawings. First, in the water cooling apparatus according to the invention of claim 1, the hollow extruded product M continuously extruded from the extruder E in the substantially horizontal direction enters the reduced-pressure water cooling tank 1 and gradually moves in the water. Although it cools and hardens, the water pressure is reduced or offset by the reduced pressure in the reduced-pressure water cooling tank 1, so that the outsizing unit 2 is maintained at the inlet side of the reduced-pressure water cooling tank 1 while maintaining the tensioned state by the atmospheric pressure inside the hollow. By sequentially passing through the sizing holes 21 of the plurality of sizer members 20A to 20H, the outer diameter is squeezed and cooled and hardened in a stepwise manner. There is no regular change in diameter and no reduction in roundness, and when the outsizing unit 2 is exited, the curing has progressed considerably, especially the hardness of the outer peripheral part that is in contact with the cooling water W. Because you are, without concern that results in a decrease of the diameter change and roundness in the process of moving the water subsequent decompression water cooling tank 1, it exits manufacturing a hollow extrusion having a high dimensional accuracy have.

  According to the invention of claim 2, the outsizing unit 2 includes an inlet block portion 2a fixed to the front end wall of the reduced-pressure water cooling tank 1, and a multistage sizing portion 2b holding the plurality of sizer members 20A to 20H. Since it comprises, it is easy to assemble and assemble it to the reduced-pressure water cooling tank 1, and the cooling water passage 23 surrounding the entrance 22 of the inlet block 2a suppresses the temperature rise of the inlet block 2a. Even the entrance 22 portion can impart a cooling action to the hollow extruded product M, and the outsizing property is further improved.

  According to the invention of claim 3, the outsizing unit 2 includes a plurality of ring-shaped sizer members 20 </ b> A to 20 </ b> H each having a sizing hole 21 at the center, and a plurality of support shafts 25. Therefore, the sizer members 20A to 20H can be easily assembled in an arrangement form in which a predetermined distance is maintained between them, and the sizer members 20A to 20H can be attached to and detached from the support shaft 25. From the above, according to the outer diameter of the hollow extruded product M to be sizing, the sizer members 20A to 20H can be easily replaced with those having the corresponding Ising hole diameter, and depending on the resin type and properties of the hollow extruded product M Then, by adjusting the arrangement interval of the sizer members 20A to 20H by exchanging the spacers 24, or by exchanging the sizer members 20A to 20H. It is also possible to change the sizing stages.

  According to invention of Claim 4, the sizing hole 21 of the sizer member 20H arrange | positioned at the tail is comprised by the center hole of the cylindrical part 20b which protrudes to the inner back side of the pressure-reduced water cooling tank 1, and this cylindrical part 20b Since the hollow extruded product M passing through the outsizing unit 2 is considerably hardened, the hollow portion M is formed in the cylindrical portion 20b in the final stage of sizing. , The outer peripheral portion is continuously sized while receiving the pressure reducing action in the reduced pressure water cooling tank 1 and the cooling action by the cooling water W through the surrounding small holes 20c, so that higher dimensional stability is obtained.

  According to the invention of claim 5, since the hollow extruded product M passes through the water of the front bus portion 2c and falls before entering the sanding portion (multistage sizing portion 2b) of the outsizing unit 2, the sanding portion Since the sizing action is more stably and reliably performed, the entrance 22 to the sanding portion is sealed with the water W of the front bus portion 2c, so that external air is bubbled from the entrance 22 As a result, the reduced pressure state in the reduced pressure water cooling tank 1 can be stably maintained.

  According to the sixth aspect of the present invention, the front bus portion 2c overflows the cooling water W introduced from the position closer to the bottom and discharges it to the outside. Therefore, the water channel configuration is simplified and the front bus portion 2c The insertion guide member 27 provided at the front end can be attached / detached and replaced with one having a diameter of the insertion hole 27a according to the outer diameter of the empty extruded product M to which the insertion guide member 27 is applied.

  Below, the water cooling apparatus of the hollow extrusion molding which concerns on one Embodiment of this invention is demonstrated concretely with reference to drawings. FIG. 1 is a schematic side view of a production line of a hollow extruded product to which the water cooling apparatus of the present invention is applied, FIG. 2 is a schematic longitudinal side view including a piping system of the water cooling apparatus, and FIG. 3 is a reduced pressure water cooling tank of the water cooling apparatus. Front view of the front end side, FIG. 4 is a cross-sectional plan view of the front end portion of the reduced-pressure water cooling tank in a drained state, FIG. 5 is a longitudinal side view of the front end portion of the reduced-pressure water cooling tank, and FIG. It is a vertical front view of the part side.

  In the production line for the hollow extruded product shown in FIG. 1, a water-cooling device A, a take-up machine P, and a cutting machine C are sequentially arranged downstream from the extruder E, and the synthetic resin heated and melted in the extruder E. Is continuously extruded in a substantially horizontal direction through a die D at the outlet of the extruder E as a required hollow cross-sectional shape such as a pipe or tube, and the high-temperature hollow extruded product M is taken out via the take-up machine P while being cooled with water. It cools and hardens by letting the water of the pressure-reduced water cooling tank 1 in the apparatus C pass, and it cuts into predetermined length with the cutting machine C, and is commercialized.

  As shown also in FIG. 2, the water cooling apparatus A has a horizontally long box-like closed sealed water-cooled water tank 1 with an outsizing unit 2 fitted at the front end thereof and a lower part of the vacuum water-cooled tank 1. In addition, a horizontally long rectangular parallelepiped closed adjustment water tank 3 and a horizontally long rectangular parallelepiped water storage tank 4 that is open upward are disposed, and a water cooler 5 serving as a water cooling means is disposed on the side of the reduced-pressure water cooling tank 1. Is arranged.

  In the reduced-pressure water-cooled tank 1, an overflow pipe 61 and a ventilation pipe 62 each having an upper end opened vertically from the inner bottom of the tank body 11 on the front side. Accordingly, the upper end of the aeration pipe 62 is set higher than the upper end of the overflow pipe 61, and the cooling water W is accommodated in the reduced-pressure water cooling tank 1 at a water level regulated by the opening position of the overflow pipe 61. The upper side forms an air layer 10. In addition, a plurality of water inlets 13 and water outlets 14a and 14b are provided at the bottom of the reduced-pressure water cooling tank 1 at predetermined intervals in the longitudinal direction. Further, the reduced-pressure water cooling tank 1 includes a water temperature gauge WT for measuring and displaying the water temperature on the front side of the tank, a vacuum control valve CV connected to the air layer 10, a vacuum pressure gauge PG for measuring the pressure of the air layer 10, and a vacuum pressure gauge. An automatic pressure regulating valve OV that operates and stops according to the measured value of PG is attached to each.

  On the other hand, a sealing tank 7 is integrally formed as an extension of the tank body 11 at the rear end on the outlet side of the reduced-pressure water cooling tank 1, and the partition wall 7 a between the sealing tank 7 and the reduced-pressure water cooling tank 1 and the sealing tank 7 A sealing material 71 that allows the hollow extruded product M to pass through in a liquid-tight manner is fitted to the rear end wall 7b. An overflow pipe 63 having an upper end opened near the top of the tank is also erected vertically from the inner bottom, and a water inlet 72 is provided at the bottom.

  As shown in FIGS. 3 to 5, the outsizing unit 2 includes an inlet block portion 2 a disposed outside the front end wall 11 a of the tank body 11 in the reduced-pressure water cooling tank 1, and an inner end portion of the inlet block portion 2 a. A multi-stage sizing portion 2b that is screwed into the end side and protrudes from the opening portion 11b of the front end wall 11a into the inner side of the reduced-pressure water cooling tank 1, and a front bus portion 2c that is arranged on the front side of the inlet block portion 2a. It is configured.

  The inlet block portion 2a is formed by fitting the annular convex portion 201a on the inner end central side to the opening portion 11b of the front end wall 11a of the reduced-pressure water cooling tank 1, and connecting the front end wall 11a to the front end wall 11a via the annular gasket 28 on the inner end peripheral side. The mounting base 201 is screwed and an annular front plate 202 is screwed to the outer surface of the mounting base 201. The annular front plate 202 side is located at the center of both the mounting base 201 and the annular front plate 202. The entrance 22 that opens forward in a trumpet shape is provided through.

  The multi-stage sizing portion 2b includes a plurality of ring-shaped (eight in the figure) sizer members 20A to 20H each having a sizing hole 21 at the center, and a front end screw portion 25a screwed to the rear end surface of the front end sizer member 20A. And a plurality of square bar-like support shafts 25 penetrating the peripheral portions of the other sizer members 20B to 20H, and inserted between the support shafts 25 and interposed between the sizer members 20A to 20H. Cylindrical spacers 24, and fastening nuts 26 screwed to the rear end screw portions 25b of the respective support shafts 25, and sizing holes of the sizer members 20A to 20H by tightening these fastening nuts 26. Are integrated in a state where the centers of 21... Are located on the same axis.

  Here, it is assumed that the sizing holes 21 of the sizer members 20A to 20H change in a plurality of stages so that not all have the same hole diameter but the diameter decreases toward the rear side. For example, when the set outer diameter of the final hollow extruded product is 3.80 mm, the sizing hole diameter is 4.10 mm for the sizer members 20A to 20E, 4.05 mm for the sizer members 20F and 20G, and 3 for the sizer member 20H. .96mm and 3 stages. In this case, the change from the sizing diameter of 3.96 mm to the set outer diameter of 3.80 mm due to the last sizer member 20H is hollow in the process of moving through the water in the vacuum water cooling tank 1 after leaving the outsizing unit 2. This is done by natural shrinkage accompanying the cooling and hardening of the extruded product M.

  Thus, the foremost sizer member 20A of the multi-stage sizing portion 2b has a male screw 203 on the outer periphery and a cylindrical portion 204 having a sizing hole 21 on the inner side at the center of the front end. Is inserted into the entrance 22 of the inlet block portion 2a, and the external male screw 203 is screwed into the inner peripheral female screw portion 201b of the inlet block portion 2a, thereby connecting the multi-stage sizing portion 2b to the inlet block portion 2a. is doing. Further, the entrance block 2a has an entrance between the mounting base 201 of the inlet block 2a and the annular front plate 202 and between the mounting base 201 and the foremost sizer member 20A of the multistage sizing part 2b. The cooling water passages 23 and 23 surrounding the cooling water passage 23 are formed, and the cooling water W is circulated and supplied to both cooling water passages 23 and 23 from the outside through the inlet / outlet holes 23a formed in the inlet block portion 2a. Yes. In addition, the mounting base 201 of the sizer member 20A and the inlet block portion 2a between the outer periphery of the cylindrical portion 204 of the sizer member 20A and the inner periphery of the entrance 22 of the inlet block portion 2a and on the outer peripheral side of the cooling water passage 23. A seal ring 205 is interposed between the attachment base 201 of the inlet block 2a and the annular front plate 202 on the outer peripheral side of the cooling water passage 23.

  The front bus portion 2c includes a tank base frame 206 screwed to the front surface of the inlet block portion 2a, a U-shaped end plate 207 screwed to the front end of the tank base frame 206, and a U-shape of the end plate 207. A front bus 29 opened upward is constituted by the insertion guide member 27 that closes the central recess 207a. Thus, the insertion guide member 27 is formed in a disc shape having an insertion hole 27a for the hollow extruded product M at the center, and the end plate 207 is inserted into the end plate 207 via a horseshoe-shaped holding frame 208 screwed to the end plate 207. It is fitted on the front side. Further, the end plate 207 is provided with water inlets 29a and 29a (see FIGS. 3 and 5) located near the bottom of the front bus 29 so that the cooling water W supplied from the outside can be supplied with water. While introducing into the front bus 29 continuously from the inlets 29a and 29a, the excess water W overflows from the upper edge 29b of the front bus 29, and flows outside. In addition, a water receiving tray 210 that covers the entire lower side of the inlet block portion 2a of the outsizing unit 2 and the front bus portion 2c is stretched at the lower part of the front end of the vacuum water cooling tank 1, and overflows from the front bus 29. Water W is received by the water receiving tray 210 and is discharged from the drain pipe 211.

  On the other hand, as shown in detail in FIG. 6, a guide mounting rail 15 having a T-shaped cross section is disposed along the longitudinal direction on the inner bottom portion of the reduced-pressure water cooling tank 1, and the guide mounting rail 15 is substantially L-shaped. A plurality of guide support frames 16 are fitted at predetermined intervals. A horizontal support shaft 17a that rotatably supports a pincushion-shaped guide roller 17 is held on the upper portion of the vertical piece 16a of each guide support frame 16, and the hollow extruded product M is formed of the guide rollers 17. It is set to move in the water in the reduced pressure water cooling tank 1 while being prevented from rising through the lower side. The guide support frame 16 has a lower U-shaped frame portion 16a slidably fitted to the guide mounting rail 15 and can be fixed at an arbitrary position by tightening a fixing screw 15c, and the horizontal support shaft in the vertical piece 16a. The holding position of 17a can be adjusted up and down according to the outer diameter of the hollow extruded product M. Further, the overflow pipe 61 and the ventilation pipe 62 are fitted on the tops of the pipe bodies 61a and 62a so that short cylindrical tube members 61b and 62b whose upper ends are obliquely cut are slidably fitted up and down, and these cylindrical port members 61b and 62b are fitted. Is fixed at a predetermined height by tightening the thumbscrews 61c and 62c.

  The tank body 11 of the reduced-pressure water-cooled tank 1 is opened upward, and is placed on the tank body 11 via a packing 18 attached to the upper surface side of the upper edge portion 11a bent inwardly in a U-shape. When the glass lid plate 19 is placed, the inside is kept airtight. Thus, the entire length of the reduced-pressure water-cooled tank 1 is configured to be covered with a plurality of cover plates 19, and each cover plate 19 has a pair of metal strips 19a fixed to the outer surface side along the width direction, Each end of 19a is pivotally attached to a bracket 11b fixed to the tank body 11 via a pivot pin 19b, and a handle 19c attached between the other ends of both metal strips 19a and 19a is used. It can be opened and closed.

  As shown in FIG. 2, the adjustment water tank 3 contains the cooling water W up to a predetermined water level and the upper part on the inner side constitutes the air layer 30, as in the reduced-pressure water cooling tank 1. And in the longitudinal direction one end side of this adjustment water tank 3, while supplying the cooling water W in the said adjustment water tank 3 to the pressure reduction water cooling tank 1 via the water supply pump P1, it leads out from the bottom part vicinity, and an upper wall A vacuum suction line VL for sucking the air in the air layer 30 through the vacuum pump VP is connected to an intake port 31 provided in the section. EC is an atmospheric discharge device connected to the vacuum pump VP.

  The water supply pipe L1 is provided with an on-off valve SV and a flow meter F1 on the upstream side close to the water supply pump P1, and is branched into a plurality on the downstream side, and each branched pipe is decompressed via the on-off valve SV. Each water inlet 13 of the water cooling tank 1 is connected. Further, a water injection pipe L4 branched from the water supply pipe L1 is provided on the outlet side of the vacuum pump VP, and one pipe L4a further branched from the water injection pipe L4 is connected to the seal tank via the on-off valve SV. 7 and the other pipe L4b branched from the water injection line L4 serves as a water injection path to a sizing tank (not shown), and cooling water is supplied from the sizing tank to the outsizing unit. 2 is supplied to each part.

  On the other hand, on the upper wall portion on the other end side in the longitudinal direction of the adjustment water tank 3, two water conduits 32 having lower ends opened near the inner bottom are suspended and a vent hole 34 is provided. An overflow pipe L2 connected to the overflow pipe 61 of the reduced pressure water cooling tank 1 is connected to one of the water conduits 32, and a natural flow down pipe connected to the water outlet 14a of the reduced pressure water cooling tank 1 is connected to the other one. L3 is connected, and a vent line AL connected to the vent pipe 62 of the reduced-pressure water cooling tank 1 is connected to the vent hole 34. The natural flow down pipe L3 is provided with an electromagnetic switching valve EV for switching between flow and closing on the upstream side, and an on-off valve SV and a water flow meter F2 on the downstream side.

  In addition, a water supply port 35 connected to the water supply line L5a to the water cooler 5 through the open / close valve SV and a water conduit L5b from the water cooler 5 through the open / close valve SV are provided on the bottom wall portion of the adjustment water tank 3. And a drain 37 for draining water are provided. A water supply pump P2 is interposed in the water supply line L5a, and the water W in the adjustment water tank 3 is sent to the water cooler 5 by the water supply pump P2 to be cooled, and the cooled water W is adjusted to the adjustment water tank 3 I try to return it inside. Furthermore, in the adjustment water tank 3, the attached water level sensor 38 detects whether or not the water level is within an appropriate range and the presence or absence of water W in the tank. L6 is a water injection pipe for injecting city water (tap water) into the adjustment water tank 3.

  In the water storage tank 4, the drainage from the drainage pipe L7a connected to the water outlet 14b on the rear side of the decompression water cooling tank 1 and the drainage from the drainage pipe L7b connected to the overflow pipe 72 of the seal tank 7 are combined drainage. It flows in via the pipe line L7 and drains to the outside from the drain 41 at the bottom.

  In the water cooling apparatus A having the above configuration, when the hollow extruded product M immediately after extrusion is passed through the water in the reduced-pressure water cooling tank 1 and water-cooled and cured, the water in the adjusted water tank 3 cooled to the required temperature by the water cooler 5 is used. The operation of the water supply pump P1 continuously distributes and supplies the water from the plurality of water inlets 13 to the reduced-pressure water cooling tank 1 through the water supply pipe L1, and sets the electromagnetic switching valve EV of the natural flow down pipe L3 to the water-flowing state. The water W in the reduced-pressure water cooling tank 1 is circulated by returning to the adjusted water tank 3 by gravity through the natural flow down pipe L3 from the bottom side, but the amount of water supplied from the water supply pipe L1 is more than the amount of water discharged from the natural flow down pipe L3. The water W corresponding to the difference is set so as to flow down from the overflow pipe L2 to the adjusted water tank 3. This water amount setting may be performed by appropriately adjusting the amount of water supplied by the water supply pump P1 based on a comparison between the measured value by the water meter F1 of the water supply pipe L1 and the total value of the measured value by the water meter F2 of the natural flow pipe L3. . Needless to say, the water outlet 14a connected to the water drain line L7a is closed during the water cooling operation.

  An amount of water W up to a water level regulated by the upper end opening of the overflow pipe 63 is stored in the seal tank 7. During the water cooling of the hollow extruded product M, the pipe L4a is closed, while water is poured from the pipe L4b to the sizing tank (not shown), and the cooling water passage 23 of the outsizing unit 2 is supplied from the sizing tank. , 23 and the front bath 29 are continuously supplied with water. Further, during the water cooling operation, the circulating cooling of the water W in the adjusted water tank 3 is continued and stopped based on the level of the water temperature in the reduced pressure water cooling tank 1 measured by the water temperature gauge WT. In addition, the water temperature setting is a range of about 8 to 18 ° C., particularly 10 to 15 ° C. as the water temperature on the front side in the reduced-pressure water cooling tank 1.

  Further, during the water cooling operation, the inside of the adjustment water tank 3 is depressurized by operating the vacuum pump VP, but the air layers 10 and 30 of the reduced pressure water cooling tank 1 and the adjustment water tank 3 are communicated with each other via the vent line AL. The reduced pressure water cooling tank 1 is also in the same reduced pressure state as in the adjusted water tank 3. Thus, the pressure state of the air layer 10 in the reduced-pressure water cooling tank 1 is measured by the vacuum pressure gauge PG, but when the pressure is excessively reduced, it is adjusted to an appropriate pressure range by the vacuum adjustment valve CV. In addition, when a pressure drop exceeding the appropriate range occurs for some reason, an appropriate amount of outside air flows into the reduced-pressure water cooling tank 1 due to the operation of the automatic vacuum control valve AV whose operation conditions are set in advance. Automatically return to. The set pressure of the air layer 10 of the reduced-pressure water cooling tank 1 varies depending on the diameter and thickness of the hollow extruded product M, the resin type, the passing speed, the depth from the water surface, etc. A pressure lower by about 5 to 20 MPa is preferable.

  According to such a water cooling apparatus A, the hollow extruded product M continuously extruded from the extruder E in the substantially horizontal direction gradually cools and hardens as it enters the reduced-pressure water cooling tank 1 and moves in the water. However, since the water pressure is reduced or offset by the reduced pressure in the reduced-pressure water cooling tank 1, a plurality of outsizing units 2 are provided on the inlet side of the reduced-pressure water cooling tank 1 while maintaining a tight state by the atmospheric pressure inside the hollow. By sequentially passing through the sizing holes 21 of the sizer members 20A to 20H, the outer diameter is cooled and hardened step by step (for example, in three steps). For this reason, when the hollow extruded product M exits the outsizing unit 2 without passing through the outsizing unit 2 without causing an irregular diameter change, a decrease in roundness, bending or the like. Then, the curing has progressed considerably, especially since the hardness of the outer peripheral part that is in contact with the cooling water W has increased, the diameter change and the roundness decrease in the process of moving in the water in the reduced-pressure water cooling tank 1 thereafter, There is no concern about bending or the like, and a hollow extruded product having high dimensional accuracy can be produced.

  In addition, in this embodiment, the sizing hole 21 of the sizer member 20H arranged at the tail is constituted by the central hole of the cylindrical portion 20b projecting inwardly of the reduced-pressure water cooling tank 1, and the longitudinal direction of the cylindrical portion 20b , The hollow extruded product M passing through the outsizing unit 2 is in the cylindrical part 20b at the final stage of sizing where the curing has progressed considerably. As a result of continuously sizing the outer peripheral part while receiving the pressure reducing action in the reduced pressure water cooling tank 1 and the cooling action by the cooling water W through the surrounding small holes 20c, higher dimensional stability is obtained. Moreover, before the hollow extruded product M enters the multi-stage sizing portion 2b of the outsizing unit 2, the temperature passes through the water in the front bus portion 2c, so that the sizing action in the multi-stage sizing portion 2b is more stable. Certainly done. Furthermore, since the outsizing unit 2 includes the inlet block portion 2a and the multistage sizing portion 2b, it is easy to assemble and assemble it to the reduced-pressure water cooling tank 1, and cooling around the entrance 22 of the inlet block portion 2a. The water passages 23 and 23 suppress the temperature rise of the inlet block portion 2a, and the cooling action for the hollow extruded product M can be imparted even at the entrance 22 portion, so that the outsizing property is further improved.

  On the other hand, the multi-stage sizing portion 2b of the outsizing unit 2 includes a plurality of ring-shaped sizer members 20A to 20H each having a sizing hole 21 at the center, and a plurality of support shafts 25 through spacers 24 at the periphery. Since it is a supported structure, the sizer members 20A to 20H can be easily assembled into an arrangement configuration in which a predetermined interval is maintained between them, and the sizer members 20A to 20H can be attached to and detached from the support shaft 25. Depending on the outer diameter of the hollow extruded product M to be sized, the sizer members 20A to 20H can be easily replaced with those having the corresponding Ising hole diameter, and depending on the resin type and properties of the hollow extruded product M, Adjustment of arrangement intervals of sizer members 20A to 20H by replacement of spacers 24, and replacement of sizer members 20A to 20H It is possible to make changes of sizing the number of stages by. In addition, the insertion guide member 27 provided at the front end of the front bus portion 2c can be easily attached / detached and replaced with one that fits the outer diameter of the blank extruded product M to which the diameter of the insertion hole 27a is applied by removing the pressing member 208. it can.

  In the reduced-pressure water cooling tank 1 of this embodiment, a stable reduced pressure state is maintained by the communication between the air layer 10 and the air layer 30 of the adjustment water tank 3, and the water supplied from the adjustment water tank 3 by the pump P1 is supplied to the reduced-pressure water cooling tank 1. Since the drainage from the reduced-pressure water cooling tank 1 to the adjustment water tank 3 is performed by natural flow through the overflow pipe L2 and the natural flow-down pipe L3, the water flow in the reduced-pressure water cooling tank 1 is Since it is calm and stable without turbulence, it does not cause undulations and fluctuations, and there is no pressure fluctuation of the air layer 10 due to undulations, so hollow extrusion molding caused by the flow, fluctuations, undulations, pressure fluctuations, etc. of the cooling water W The distortion of the product M is also suppressed, so that a hollow extruded product having high dimensional accuracy can be obtained. Further, in the reduced pressure water cooling tank 1, the inlet side and the outlet side of the hollow extruded product M are sealed with water from the front bath portion 2c and the seal tank 7, so that external air enters the inside as bubbles from the inlet / outlet. Therefore, the internal decompressed state can be stably maintained.

  In the above-described embodiment, the multi-stage sizing portion 2b of the outsizing unit 2 is provided with the eight sizer members 20A to 20H and the sizing is performed in three stages. However, in the present invention, a plurality of sizer members are provided. Moreover, what is necessary is just to be able to perform sizing of a plurality of stages, and the arrangement interval of the sizer members, the switching position of the sizing stage, and the like may be appropriately set according to the resin type and properties of the target hollow extruded product M.

  The pressure in the vacuum water cooling tank 1 may be reduced by directly sucking from the air layer 10 with the vacuum pump VP. Further, for the circulation supply of the cooling water W into the reduced-pressure water cooling tank 1, various supply mechanisms other than the pipe line configuration illustrated in FIG. 2 can be adopted, and the adjustment of the circulation supply amount of the cooling water W is automatically controlled. You may make it carry out by a system. In addition, in the water cooling device M of the present invention, the length of the reduced-pressure water cooling tank 1, the number and arrangement of the water inlet 13 and the water outlets 14a and 14b, the piping configuration of each part, and the type of valve interposed in each pipeline In addition to the embodiment, various design changes can be made to the detailed configuration such as the interposition position, the configuration of the auxiliary equipment such as the water cooler 3, the water storage tank 4, and the seal tank 7.

It is a schematic side view of the manufacturing line of the hollow extrusion molding to which the water cooling device of the hollow extrusion molding concerning the present invention is applied. It is a schematic longitudinal side view including the piping system of the water cooling device. It is a front view of the front end side of the decompression water cooling tank of the water cooling device. It is a cross-sectional top view in the water draining state of the front-end part of the said pressure reduction water cooling tank. It is a vertical side view of the front-end part of the same decompression water cooling tank. It is a longitudinal front view of the front side of the vacuum water cooling tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-reduced water cooling tank 10 Air layer 2 Outsizing unit 2a Inlet block part 2b Multistage sizing part 2c Front bus part 20A-20H Sizer member 20a Substrate part 20b Cylindrical part 20c Small hole 21 Sizing hole 22 Entrance 23 Cooling water passage 24 Spacer 25 Support shaft 27 Insertion guide member 27a Insertion hole 5 Water cooler (water cooling means)
A Water cooling device AL Vent line (Vacuum suction means)
E Extruder L1 Water supply pipeline (cooling water circulation supply means)
L2 Overflow pipe (cooling water circulation supply means)
L3 Natural flow pipe (cooling water circulation supply means)
M Hollow extruded product P1 Water supply pump (cooling water circulation supply means)
VP vacuum pump (vacuum suction means)
W Cooling water

Claims (6)

The hollow extruded product continuously extruded from the extruder in a substantially horizontal direction is provided with a reduced-pressure water-cooled tank that passes and cools in the water, and the hollow is introduced into the reduced-pressure water-cooled tank at the molded product inlet of the reduced-pressure water-cooled tank. An outsizing unit that regulates the outer shape of the extruded product is fitted, a cooling water circulation supply unit that circulates and supplies cooling water into the reduced-pressure water cooling tank, and an air layer that is configured in the upper part of the reduced-pressure water cooling tank. And a vacuum suction means for setting a predetermined reduced pressure state,
The outsizing unit has a plurality of sizer members each having a sizing hole through which the hollow extruded product is inserted, and the sizer member positions the center of the sizing hole on the same axis in the water in the vacuum water cooling bath. Are arranged at predetermined intervals, and the sizing hole diameters of these sizer members are changed in multiple stages so that the diameter is reduced toward the rear side.
The hollow extruded product extruded from the extruder and passing through the reduced-pressure water-cooled tank has an outer diameter in the process of sequentially passing through the sizing holes of the plurality of sizer members while maintaining a state of being tightly stretched by the pressure inside the hollow. A water-cooling device for a hollow extruded product configured to be cooled while being squeezed.   The outsizing unit has an entrance for the hollow extruded product, an entrance block portion fixed to a front end wall of the vacuum water cooling tank, and a plurality of sizer members for holding the plurality of sizer members in the entrance block portion. The water cooling apparatus for a hollow extruded product according to claim 1, further comprising a multi-stage sizing portion having a proximal end fixed thereto, and a cooling water passage surrounding the entrance opening provided in the inlet block portion.   In the outsizing unit, the plurality of sizer members each formed in a ring shape centered on a sizing hole are supported at a peripheral portion by a plurality of support shafts, and are spaced apart from each other by a spacer. The water cooling device for a hollow extruded product according to claim 1 or 2, wherein the water cooling device is arranged so as to be detachable from the support shaft.   The sizer member arranged at the rear end has a cylindrical portion protruding from the substrate portion to the inner back side of the vacuum water cooling tank, and a central hole penetrating from the substrate portion to the tip of the cylindrical portion forms a sizing hole, The water cooling device for a hollow extruded product according to any one of claims 1 to 3, wherein a large number of small holes are formed through the entire cylindrical portion.   The outsizing unit includes a front bath portion that accommodates cooling water at least up to a water level at which the entrance is immersed, outside the entrance of the hollow extrusion, and the hollow extrusion that is extruded from an extruder is the front. The water cooling device for a hollow extruded product according to any one of claims 1 to 4, wherein the water cooling device is configured to pass through water in a bath portion and enter a reduced-pressure water cooling tank.   The front bus portion is configured so that cooling water introduced from a position near the bottom overflows and is discharged to the outside, and an insertion guide member having an insertion hole for a hollow extruded product at the front end is removably fitted. The water-cooling device for a hollow extruded product according to claim 5, wherein the water-cooling device is provided.

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