JP2000263634A - Pipe former equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove bubbles sticking on the surface of a pipe due to cavitation or the like in a process of cooling the pipe in former equipment which is used in a process of extrusion molding of the pipe. SOLUTION: A water supply port for supplying water onto a pipe surface is provided in an inlet part of a forming die 2 which forms a pipe P melt- extruded from a mouthpiece of an extruder, while a suction port 23 for removing by vacuum suction a water film and bubbles sticking on the pipe surface is provided in the forming die 2 on this side of a position where the pipe P is immersed in cooling water. Inside a vacuum cooling water tank 3, a nozzle 4 having water jet ports formed in the shape of a ring is provided and thereby the water is jetted onto the pipe surface to remove the bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a former device for forming a pipe extruded at a predetermined speed from an extruder, cooling the same, and sending the pipe to a take-up machine in an extrusion molding process of a synthetic resin pipe.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional pipe former device, which comprises a forming die 101 for drawing in a pipe P melted and extruded from a die 107 of an extruder, and an inner part in which cooling water is stored. A cooling water tank 102 having a certain degree of vacuum pressure (30 to 40 mmHg). A part of the forming die 101 is protruded into the cooling water tank 102, and a plurality of radially extending slits 103 are formed in the protruding part. At the same time, supply ports 104 and 105 for ejecting air and water are provided at the entrance of the forming die 101 for the purpose of reducing the sliding resistance between the surface of the pipe P and the inner peripheral surface of the forming die 101. Was. In the figure, reference numeral 108 denotes a take-off machine. In forming the pipe P by this apparatus, the pipe P extruded from the extruder is drawn into the forming die 101, and the surface of the pipe P is brought into close contact with the inner peripheral surface of the forming die 101 through the slit 103 to expand in the radial direction. Cooling is performed with cooling water while applying force, and the pipe P is corrected into a perfect circular shape while passing through the cooling water tank 102, and is cooled and solidified.

Further, water jetted from the supply port 105 to the surface of the pipe P at the inlet of the forming die 101 comes into contact with the pipe P to be in a high-temperature and low-pressure state to generate bubbles due to cavitation. If it adheres to the surface of the pipe P for a long time, the adhered portion is not sufficiently cooled, and a trace of the adhered air bubbles may remain to cause poor appearance. Therefore, nozzles 106 are arranged around the pipe P moving in the cooling water tank 102, and water is jetted from the nozzle 106 to the surface of the pipe P to remove bubbles attached to the pipe surface.

[0004]

In order to reduce the sliding resistance between the pipe P and the forming die 101, it is indispensable to spray water onto the pipe surface P inside the forming die 101, as in the conventional apparatus. Cooling water tank 102
However, there is a problem that the bubbles adhering to the pipe surface cannot be completely removed only by jetting water from the nozzle 106 into the pipe P.

The present invention has been made in view of the above-mentioned problems of the prior art, and in a former apparatus used in an extrusion molding process of a synthetic resin pipe, sufficient air bubbles adhering to the pipe surface due to cavitation and the like in a process of cooling the pipe are taken. It is an object of the present invention to make it possible to remove it.

[0006]

The poor appearance of the pipe due to air bubbles is caused by insufficient cooling of the portion of the pipe surface to which air bubbles have adhered. Therefore, it is preferable to remove bubbles as much as possible before the pipe is immersed in the cooling water and rapidly cooled. Therefore, the pipe former device of the present invention, in which a pipe is cooled by passing through a vacuum cooling water tank while being formed by a forming die, is provided with a water supply port for supplying water to the pipe surface at the inlet of the forming die, and the pipe is provided with cooling water. A suction port for sucking and removing a water film and bubbles adhering to the pipe surface was provided on the forming die before the position where it was immersed. According to this structure, it is possible to uniformly cool the pipe surface evenly without contacting the pipe surface in a high temperature state at the inlet of the forming die, removing bubbles attached to the pipe as steam bubbles. .

On the other hand, air bubbles are also generated by cavitation while the pipe is moving in the cooling water tank. That is, even if the pipe is immersed in the cooling water in the cooling water tank, the surface temperature of the pipe is higher than that of the cooling water, and air solubility in the water is reduced at the pipe surface, so that bubbles are generated. Therefore,
Although it is necessary to remove these bubbles, the bubbles cannot be completely removed by a nozzle as in the conventional apparatus. Therefore, the nozzle of the nozzle for ejecting water installed in the cooling water tank is formed in a ring shape surrounding the peripheral surface of the pipe so that the water ejected from here is applied to the entire surface of the pipe. And air bubbles adhering to the pipe can be scattered and removed without leaking.

[0008]

Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a pipe former device according to an embodiment of the present invention, and FIG. 2 is an enlarged diagram illustrating a configuration of an inlet portion of a forming die.

The former 1 shown in the figure has a pipe P melt-extruded from a die (not shown) of an extruder.
Forming die 2 for drawing and forming the pipe, cooling water tank 3 for immersing pipe P formed by forming die 2 in cooling water to cool the pipe P, and sending it to a take-off machine (not shown). Nozzle 4.

The forming die 2 is provided on the water tank wall of the cooling water tank 3, and has a tip entrance portion protruding toward the extruder and another portion protruding into the cooling water tank 3. As shown in FIG. 2, inside the forming die 2 on the inlet side, a water supply port 21 for spouting water on the surface of the pipe P is provided, and the forming water projecting into the cooling water tank 3 is formed. The die 2 is provided with a plurality of radially extending slits 22. Further, on the forming die 2 closer to the cooling water tank 3 than the supply port 21 and before the position where the pipe P moving in the forming die 2 is immersed in the cooling water of the cooling water tank 3, the surface of the pipe P is adhered to. A suction port 23 for sucking and removing the formed water film and the like is provided in a belt shape along the peripheral surface of the pipe P. The suction port 23 is provided with a ring-shaped support 24 having a groove 24a on the inner side thereof, which is tightly mounted on the outer peripheral surface of the forming die 2, and a vacuum pump (not shown) installed outside the apparatus and the inside of the groove 24a. By depressurizing the space defined by the groove 24a with a vacuum pump, the water film and the bubbles adhering to the surface of the pipe P are vacuum-suctioned through the slit 22 and are removed from the surface of the pipe P. It can be removed.

The inside of the cooling water tank 3 in which cooling water is stored is kept airtight, and a predetermined vacuum pressure (3) is provided by a vacuum pump (not shown) installed on the water tank wall above the water surface.
0 to 40 mmHg). Although not shown, the water in the water tank is maintained at a constant water level by a water level setting device, a water supply valve, or the like, and is maintained at a constant temperature by a heat exchanger, a thermometer installed in the tank, or the like. Has become.

The nozzle 4 is formed in a ring shape so as to surround the outer peripheral surface of the pipe P, and is provided so that the pipe P moving in the cooling water tank 3 passes therethrough. The nozzle 4 is connected to a water supply pump (not shown) installed outside the apparatus, and ejects water from a ring-shaped opening 4 a to the peripheral surface of the pipe P to disperse bubbles attached to the pipe P. , Can be removed from the surface of the pipe P.

According to the forming apparatus 1 of the present embodiment configured as described above, the pipe P melt-extruded from the extruder.
Is drawn into the sizing die 2 and formed, the water jetted from the water supply port 21 at the inlet of the sizing die 2 becomes steam bubbles and adheres to the pipe surface, but the pipe P is cooled in the cooling water tank 3. Previously, the water is sucked together with the water film at the suction port 23 provided in the sizing die 2 and removed from the surface of the pipe P. The pipe P from which the air bubbles have been removed at the suction port 23 moves into the depressurized cooling water tank 3, and the surface of the pipe P is suction-adhered to the inner peripheral surface of the forming die 2 through the slit 22 to expand in the radial direction. It is cooled with cooling water while applying force. Also in this cooling process, air bubbles are generated and adhere to the pipe surface because the air solubility of the pipe surface portion is reduced. However, when the pipe P passes through the ring-shaped nozzle 4, the air bubbles are discharged from the jet port 4 a around the pipe P. It is scattered by the water jetted to the surface and removed from the surface of the pipe P.
In this way, while passing through the former device 1, it is possible to form a pipe P which is corrected into a perfect circular shape, cooled and solidified, and has no trace of air bubbles on the surface, and sent to a take-up machine in the next step. it can.

[0014]

According to the pipe former device of the present invention,
In the process of cooling the pipe, bubbles adhering to the pipe surface are sufficiently removed by cavitation or the like, and the pipe can be formed into a pipe that has been corrected into a perfect circular shape with no trace of bubbles on the surface.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a pipe former device of the present invention.

FIG. 2 is an enlarged view showing a configuration of an entrance portion of a forming die of the apparatus of FIG.

FIG. 3 is a diagram illustrating an example of a configuration of a conventional pipe former device.

[Explanation of symbols]

 1 Forming device 2 Forming die 22 Slit 23 Suction port 24 Support 3 Cooling water tank 4 Nozzle

Claims (2)

[Claims] 1. A pipe former apparatus for cooling a synthetic resin pipe melt-extruded from a die of an extruder by passing through a vacuum cooling water tank while forming the pipe with a forming die. And a suction port for sucking and removing a water film and air bubbles adhering to the surface of the pipe at a forming die before a position where the pipe is immersed in the cooling water. 2. A vacuum cooling water tank is provided with a nozzle having a water jet formed in a ring shape, and water is jetted from the ring-shaped water jet to a pipe surface to remove bubbles. The pipe former device according to claim 1.