JP2002144408A - Method and device for cooling extrusion molded pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cooling an extrusion molded pipe by which a synthetic resin pipe can be efficiently cooled after extrusion molding and the manufacturing cost of the synthetic resin pipe can be reduced by improving the extrusion rate and curtailing equipment cost and the like, and a cooling device. SOLUTION: Cooling water is sprayed from a shower head 33 to the outer face of a synthetic resin pipe 32 molded by extrusion from an extruder and cooling air is blown off by an air fan 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for cooling an extruded pipe, and more particularly, to a method and an apparatus for efficiently cooling a synthetic resin pipe extruded from an extruder.

[0002]

2. Description of the Related Art Conventionally, as a means for cooling a high-temperature synthetic resin pipe extruded from an extruder to near normal temperature,
As shown in the schematic cross-sectional front view of FIG. 3, a cooling water tank 11 having a sizing former and a shower tank 12 are connected in series at the subsequent stage of the extruder 10, and are extruded into cooling water filled in the cooling water tank 11. After passing through the high-temperature synthetic resin pipe 13, cooling water is sprayed to the outer surface of the pipe from a large number of shower heads 14 provided in the shower tub 12,
The synthetic resin pipe 13 was cooled to around room temperature.

[0003] The cooling water sprayed from the shower head 14 is supplied to each shower head 14 from a water tank 15 for storing the cooling water by a path 17 provided with a pump 16. Is returned to the water tank 15 through the route 18. Further, a cooling tower (cooling tower) 19 is attached to the water tank 15, and the temperature of the cooling water is lowered by circulating the cooling water in the water tank 15 to the cooling tower 19 by the circulation pump 20. The cooling water lost due to evaporation or the like is supplied from the path 21 via a ball tap or the like.

[0004]

However, the shower tub 1
Since the cooling tower 19 cools the cooling water heated by contact with the synthetic resin pipe 13 in step 2, it may be difficult to sufficiently cool the cooling water when the outside air temperature in summer is high. Was. If the cooling of the synthetic resin pipe 13 becomes insufficient, for example,
If the temperature of the synthetic resin pipe 13 is high when it is taken off by the cutter 23 and cut to a predetermined length by the cutting machine 23, a large error may occur in dimensions at the time of cutting due to thermal expansion of the synthetic resin.
There is a possibility that the length of the synthetic resin pipe 13 after cooling to the predetermined temperature becomes shorter than the set dimension. For this reason, the extrusion speed of the synthetic resin pipe 13, that is, the speed of the synthetic resin pipe 13 passing through the cooling water tank 11 and the shower tank 12, must be kept low, and the productivity at high temperatures such as in summer may decrease. This also affects the manufacturing cost.

On the other hand, it is possible to install a large-sized and high-performance cooling tower 19, or to install cooling equipment such as a refrigerator, but this not only increases equipment costs and running costs, but also increases installation space. Problems also occur.

Accordingly, the present invention provides an extruded pipe capable of efficiently cooling a synthetic resin pipe after extrusion, and reducing the production cost of the synthetic resin pipe by improving the extrusion speed and reducing equipment costs. It is an object of the present invention to provide a cooling method and apparatus.

[0007]

In order to achieve the above object, a method for cooling an extruded pipe according to the present invention is a method for cooling a synthetic resin pipe extruded from an extruder. The method is characterized in that cooling water is sprayed on an outer surface and cooling air is blown, and the cooling water is circulated.

Further, the present invention provides an apparatus for cooling an extruded pipe, which is for cooling a synthetic resin pipe extruded from an extruder, comprising: a shower tub in which the synthetic resin pipe moves in an axial direction; A shower head provided in the shower tub for spraying cooling water on the outer surface of the synthetic resin pipe, and a blower for blowing cooling air to the outer surface of the synthetic resin pipe in the shower tub,
Further, a water tank for storing the cooling water, a path for supplying the cooling water in the water tank to the shower head, a path for collecting the cooling water in the shower tank to the water tank, and supplying the cooling water to the water tank And a path.

[0009]

FIG. 1 is a cross-sectional side view of a main part showing an embodiment of a pipe cooling apparatus to which the method of the present invention is applied. This pipe cooling device includes a plurality of shower heads 33 for spraying cooling water on an outer surface of a synthetic resin pipe 32 in a shower tank 31 having a box-shaped cross section with an open upper surface, and an outer surface of the synthetic resin pipe 32 in the shower tank 31. And a blower 34 for blowing cooling air.

As shown in FIG. 1, the blower 34 can be provided with a blower body directly above the shower tub 31 to blow air directly to the outer surface of the pipe. Alternatively, an appropriate duct may be connected to the blower main body installed at an appropriate place, and air may be blown to the outer surface of the pipe through the duct. A plurality of the blowers 34 can be installed according to the length of the shower tub 31. At this time, the amount of air blown by each of the plurality of blowers 34 can be appropriately set according to the installation position of each blower 34. it can.

The blower 34 may blow air from the blower 34 to blow cooling air to the outer surface of the pipe, and conversely, draw air in the shower tub 31 to guide the cooling air to the outer surface of the pipe. You may do so. Further, the shower tub 31 can be formed in the same manner as the shower tub 12 in the conventional pipe cooling device. However, a ventilation port 35 serving as an outlet or an inlet for cooling air can be provided on the side wall 31a.

When the ventilation hole 35 is provided on the side wall 31a, the upper surface opening of the shower tub 31 is covered by a cover 3 shown by an imaginary line in FIG.
6 is preferred. In addition, shower tub 31
The cooling air discharged from the device is discharged to the outside without being discharged to the room where the device is installed, thereby suppressing an increase in temperature and humidity in the room.

The cooling water supplied to the shower head 33 is supplied to each shower head 33 from a water tank 37 for storing the cooling water through a path 39 provided with a pump 38, as in the prior art.
The cooling water after spraying is supplied to the shower tub 3
1 circulates from the bottom through the path 40 to the water tank 37. The cooling water lost due to evaporation or the like is supplied from the path 41 via a ball tap or the like.

In the cooling device thus formed, cooling water is sprayed from the shower heads 33 onto the outer surface of the synthetic resin pipe 32, and cooling air is blown onto the outer surface of the pipe by the blower 34, whereby the sprayed cooling water is sprayed. Evaporation is promoted and the latent heat of evaporation of the cooling water is reduced by the synthetic resin pipe 32.
Therefore, the synthetic resin pipe 32 can be cooled more efficiently than conventional cooling using sensible heat.

Thus, the synthetic resin pipe 32 can be reliably cooled even at a high temperature in the summer, so that the extrusion speed of the synthetic resin pipe 32 can be maintained at the same speed as the normal time, and the production can be performed even at a high temperature. The property does not decrease. Further, since the cooling efficiency is high, the synthetic resin pipe 32 can be sufficiently cooled even when the extrusion speed is increased in the normal state, so that the productivity in the normal state can be improved. On the other hand, even if the entire length of the shower tub 31 is shortened, it is possible to cool down to a predetermined temperature, so that the size of the entire extrusion equipment can be reduced by downsizing the cooling device.

Further, the temperature of the cooling water itself drops due to contact and evaporation with the cooling air, and
Since the temperature of the water returning to the water tank 37 through 0 becomes lower than before, the temperature of the cooling water in the water tank 37 can be maintained at a predetermined temperature or less without installing a cooling tower. , A smaller one can be selected. Therefore, by circulating and using an appropriate amount of cooling water, equipment costs and running costs required for the cooling tower can be reduced, and the installation space of the cooling tower and the like can be effectively used.

The extruder, the subsequent take-off device, the cutting device and the like can be used as they are, and therefore can be easily applied to existing equipment.

[0018]

EXAMPLE A polyethylene pipe was extruded as a synthetic resin pipe, and an experiment was conducted to confirm the cooling effect by blowing cooling air. Extrusion molding equipment can be used as it is, without changing the structure of the shower tub.
The tip of the duct connected to the blower was installed at three places above the 0 mm shower tub so as to face the pipe inlet side, and cooling air was blown from obliquely above the pipe. Room temperature around the shower tub is 31.8 ° C, cooling water temperature is 2
The cooling air temperature blown out from the duct was 9.7 to 31.3 ° C, and the cooling air temperature was 29.0 to 30.0 ° C.

First, when extrusion was performed with the blower stopped, the pipe outer surface temperature at the outlet of the shower tub became stable at 36.1 ° C. In this state, when air blowing by the blower is started and cooling air is blown on the outer surface of the pipe, the outer surface temperature of the pipe at the outlet of the shower tub gradually decreases, and after about 10 minutes has passed, has the temperature stabilized at around 35.3 ° C. However, the temperature then dropped again, reaching 33.3 ° C. after 27 minutes. This result is shown in FIG.
Shown in

At this time, the temperature of the cooling water sprayed from the shower head hardly changed for about 10 minutes from the start of the air supply, but then gradually decreased to about 29 minutes after 27 minutes.
° C. In other words, it indicates that the temperature of the cooling water circulating through the water tank is also reduced due to a secondary effect of blowing cooling air to the outer surface of the pipe.

[0021]

As described above, according to the present invention,
Since the extruded synthetic resin pipe can be efficiently cooled, the synthetic resin pipe can be manufactured without reducing productivity even in summer when the temperature and water temperature are high.
Further, productivity can be improved by improving the cooling efficiency, and the size and space of the cooling device and the entire extrusion equipment can be reduced, and the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of a main part showing one embodiment of a pipe cooling device to which the method of the present invention is applied.

FIG. 2 is a diagram showing a change in a pipe outer surface temperature.

FIG. 3 is a schematic sectional front view showing an example of a conventional pipe cooling device.

[Description of Signs] 31 ... shower tub, 32 ... synthetic resin pipe, 33 ... shower head, 34 ... blower, 35 ... vent, 36 ... cover, 37 ... water tank, 38 ... pump

Claims (4)

[Claims] 1. A method for cooling a synthetic resin pipe extruded from an extruder, comprising spraying cooling water on an outer surface of the synthetic resin pipe and blowing cooling air. Cooling method. 2. The method according to claim 1, wherein the cooling water is circulated. 3. An apparatus for cooling a synthetic resin pipe extruded from an extruder, comprising: a shower tub in which the synthetic resin pipe moves in an axial direction; and a synthetic resin pipe provided in the shower tub. A cooling device for an extruded pipe, comprising: a shower head for spraying cooling water on an outer surface of the pipe; and a blower for blowing cooling air to an outer surface of the synthetic resin pipe in the shower tub. 4. A water tank for storing the cooling water, a path for supplying the cooling water in the water tank to the shower head, a path for collecting the cooling water in the shower tank to the water tank, and a cooling water in the water tank. The cooling device for an extruded pipe according to claim 3, further comprising a path for supplying the pipe.