JPS5838099B2 - Screw for plastic extrusion - Google Patents

Description

[Detailed Description of the Invention] The present invention heats and cools an extrusion molding machine or a complete screw injection molding machine from the inside using a heat vip inserted into the screw, and relies on heating and cooling only from the outside of the cylinder. This relates to a structure for improving the performance of the screw, which has the effect of speeding up thermal response and reducing heat loss from the outside of the cylinder compared to the conventional method.A heat pipe is inserted into the center of the screw. When heating or cooling the metering section and melting section of the screw by exposing a part of the heat pipe outside the screw and heating or cooling this part, the heat equalizing property of the heat pipe is utilized. There are problems such as.

(1) Since the length of the heat pipe is very long at 3m to 6m, the viscous resistance of the working fluid increases in normal Winok, which reduces the amount of working fluid circulating and there is a risk that the maximum heat transfer amount will decrease. be.

(2) The length of the compression section, material supply section, and drive section is longer than the measuring section and melting section, which are the parts targeted for heating and cooling. Thick.

(3) Since it is always used horizontally and also rotates, there is a risk that the working fluid may leak inside the heat pipe container or that the flow of the working fluid within the wick may become unstable.

The screw structure according to the present invention is intended to improve these problems and provide a new structure that greatly improves the temperature control function of the screw.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a screw key for a plastics extruder according to the present invention.

A to F are symbols representing the functions of each part of the screw main body 1, and A indicates a measuring section.

In the metering section, the screw root 1' is shallow and the screws r are formed at a precise pitch, and serve to stabilize the amount of molten plastic discharged due to the rotation of the screw during extrusion or injection.

This part also has the role of completing the melting of the plastics melted in the melting section B and keeping the molten state of the plastics constant by providing sufficient pressure and stable temperature, and ensuring precise screw pitch and screw rotation. Together with this, it is an important part that determines most of the performance of an extruder or injection machine.

Therefore, heating using a heat pipe is also aimed at precisely controlling the temperature of the part.

The plastic material supplied from the extruder or injection machine is first transferred to the compression section C by the material supply section D of the screw.
sent to.

The role of the material supply section D is equivalent to that of a so-called screw conveyor.

The compression section C compresses the material heated and softened by the cylinder according to the compression ratio of the screw, and expels the air in the gap between the material chips toward the material supply section D, while extruding the plastic material toward the melting section B. It has a role.

The plastic material compressed by heat and pressure in the compression section C is melted in the melting section B while being further subjected to heat and pressure, and then press-fitted into the metering section A.

Generally, there are no clear boundaries between each section from the material supply section to the melting section.

Depending on the plastic material and the temperature conditions at the time, each part progresses while being subjected to the effects of material feeding, heating, mixing, and compression in a stepless manner.

Part E is a driving part of the screw, and is inserted and engaged with the center of the rotating main shaft of an extruder or injection machine, transmits the rotational force of the main shaft to the entire screw, and becomes a source of the plastics extrusion force.

Furthermore, when the screw rotates at high speed, self-heating is generated due to the pressure and friction between the plastic material, the inner wall of the cylinder, and the surface of the screw, which becomes a source of heat for melting the plastic.

When the amount of internal heat generated is large, the temperature of the cylinder and screw rises even if the heat generation from the cylinder is stopped, and the temperature of the cylinder and screw eventually becomes uncontrollable, which is a drawback of the conventional screw, but the screw according to the present invention uses a heat pipe. Therefore, it has the ability to control an appropriate amount of internal heat by discharging it to the outside.

Section F is a temperature adjustment section that controls the temperature inside the screw, and is configured such that a part of the heat pipe inserted into the screw is exposed outside the screw.

This part can be heated or cooled depending on the desired method,
Or, by adjusting the temperature to an appropriate temperature, the temperature of the measuring section of the screw, or the measuring section and the melting section, can be rapidly raised or cooled, or the temperature can be adjusted to an appropriate temperature by adjusting the temperature to an appropriate temperature. It can be adjusted to

2 is a heat pipe container that is inserted into the center of the screw from the end of the screw drive unit and reaches near the tip of the metering unit.

The other end is exposed outside the screw from the terminal of the drive section E, and constitutes a temperature adjustment section F.

Reference numeral 3 denotes group type wicks, which are formed in large numbers on the circumference of the inner wall of the container and are provided over the entire length of the container 2.

The group type wink is used because the heat pipe is long and requires a large amount of heat transfer.

In other words, in order to do this, it is necessary to circulate a large amount of working fluid at a high speed compared to heat pipes for other uses. A group type that can be used is desirable.

However, since it is a heat pipe installed inside the screw of an extruder or a complete screw injection molding machine, it is difficult to achieve its performance with a normal heat pipe or a normal group, so new devices such as those described below have been devised.

4 is a wick for dispersing hydraulic fluid, and a coarse braid or net is made of fine metal wire, and one or two pieces of this are used and inscribed in the surface circumference of the group wick to form a shape.

The wire for dispersing the hydraulic fluid does not necessarily have to be made of fine metal wire; it may be made of inorganic fibers as long as it is compatible with the hydraulic fluid and exhibits the functions and effects described below. It may also be Yuitsuku.

The hydraulic fluid dispersion wick has the following characteristics over the entire length of the container:
It is provided on the surface of the group at a position corresponding to the measuring part AK, or a position corresponding to both the measuring part A and the melting part B, and a position corresponding to the temperature adjusting part F.

Therefore, in this part, each part becomes a heating part and a heat radiation part, and accordingly, a large amount of working fluid evaporates and vaporizes, and a large amount of working fluid vapor condenses and liquefies. be.

Therefore, the hydraulic fluid dispersion wick 4 is It has the following effects.

(1) Efficiency is improved by increasing the evaporation area and condensation area compared to the case of only group type wicks.

(2) Even when the heat pipe rotates and the condensed working liquid reaches the upper part of the heat pipe cross section, the working liquid is retained and dispersed, so that the working liquid does not drip from the upper part of the container wall, and the dripping of the working liquid is caused by the vapor of the working liquid. Prevents heat pipe performance from deteriorating by interfering with movement or generating droplets.

(3) The hydraulic fluid is reliably delivered into the hydraulic fluid passage formed by the hydraulic fluid evaporation prevention tube 6 and the group type wick 3, which will be described later.

(4) The working fluid that has returned from the working fluid passage is uniformly dispersed over the entire inner wall of the container to improve its evaporation efficiency.

5 is a liner for improving thermal conductivity.

In order to obtain a sufficient compression ratio of the extruder screw, the depth of the screw groove is formed so that it gradually becomes deeper from the measuring section at the tip to the material supply section. Therefore, the distance from the screw surface to the heat pipe is Part B and measuring part A are farther away than other parts, and the heat capacity of the screw is also the largest in this part.

Therefore, in order to quickly and efficiently exchange heat between the material or the screw surface and the heat pipe in parts A and B, it is better to improve the thermal conductivity within the screw body in these parts. Of course.

Therefore, in this example, holes of sufficient size are cut in the A and B parts of the screws to a size that does not pose any danger in terms of screw strength, and a metal material with good thermal conductivity is inserted between the outer periphery of the heat pipe and the inner wall of the holes. After installing the liner, the front part of the screw is sealed again.

The appropriate metal to be used is copper aluminum or the like.

Furthermore, by inserting a heat pipe as the liner or configuring the liner insertion portion to have a heat pipe structure, the performance of the present screw can be dramatically improved.

6 is a tube for preventing evaporation of the working fluid. The above-mentioned hydraulic fluid dispersion wick 4 is applied over the entire length of the heat pipe container.
is inserted tightly into the inner layer of the group in all parts that are not internally covered.

Any material may be used as long as it is compatible with the working fluid, that is, it will not be corroded by the working fluid or generate non-condensable gas over a long period of time, and will not allow penetration or permeation by the working fluid and its vapor.

In this embodiment, a thin-walled metal tube is used for convenience in processing.

Since the purpose of the screw according to the present invention is to heat, cool, or adjust the temperature of the measuring part or the measuring part and the melting part to a desired temperature from inside the screw, the tube 6 is used for other parts, that is, the driving part E, the material Although the main purpose is to limit unnecessary performance of the wick by providing it on the surface of the group corresponding to the supply section D, the compression section C, and in some cases the melting section B, there are other It also has great effects.

The effects of the tube 60 are as follows. (1) As mentioned above, evaporation of the working fluid in the container other than the A section, or the A, B, and F sections is prevented.

When heat is transferred at high speed from part A or parts A and B to part F, or vice versa, in the case of a normal heat pipe, some evaporation occurs from other parts as well, and this causes the working fluid to completely disappear. The efficiency of the reheat pipe will be deteriorated by interfering with the recirculation flow.

The heat pipe used in the screw according to the present invention has a long length and transfers a large amount of heat, so depending on the heat equalization property of the heat pipe, it is possible to transfer heat from unnecessary parts to lower temperature parts. Steam often moves toward
There is a high possibility that the efficiency of heat transfer will decrease due to this.

The tube 6 covers the groups, which are passages for the working fluid, to completely prevent evaporation of the working fluid and vapor movement in unnecessary areas.

(2) Minimize the reduction in heat pipe efficiency caused by steam moving from part A or parts A and B to part F, or vice versa, which is condensed and absorbed in other parts, short-circuited, and refluxed. To prevent.

As in case (1), if there is a low-temperature part in the middle of steam movement, some of the steam will condense and be absorbed in that part, reducing the efficiency of the heat pipe. Without being absorbed, therefore minimal vapor condenses on the tube surface, raising the temperature of that very surface area and minimizing subsequent vapor condensation.

In addition, the small amount of working fluid that condenses inside the tube is not absorbed by the tube, so it does not reduce the amount of working fluid circulating within the group, and the working fluid inside the tube is heated by the high-temperature steam flowing inside the tube at high speed. Then, it turns into steam again or is swept away by steam, and continues to circulate without short-circuiting and refluxing.

(3) The working fluid circulating within the group is completely retained within the working fluid passage formed by the tube 6 and the group 3 and can continue to circulate even when the screw and heat pipe rotate.

In the case of an open type group, when the heat pipe rotates at a low speed, the group type wick does not have enough capillary force to hold the working fluid against gravity, so there will be numerous drips of working fluid in a long container. As a result, the steam passage is disturbed, and the efficiency of the heat pipe is greatly reduced, and in some cases, there is a possibility that the heat pipe may even lose its characteristics as a heat pipe.

The tube 6 in the screw heat pipe according to the present invention can completely prevent this phenomenon.
This effect is extremely important.

(4) The reflux rate of the working fluid is doubled to greatly increase the maximum heat transfer amount of the heat pipe.

In the case of normal Wisog heat pipes used horizontally, the circulation of the working fluid is carried out only by capillary action.
In the case of a group type pump, it depends on the interaction of the flow of the hydraulic fluid due to capillary action and the difference in water head.

The tubes 6 according to the present invention are formed in close contact with each group, so that each group is a conduit or tube.

Therefore, once the working fluid begins to flow back into the tube-shaped groups due to the high head of the working fluid condensation section and the low water head of the evaporation section, each group becomes a siphon, exerting a strong suction force unlike a simple capillary action or liquid flow. This allows the hydraulic fluid to circulate at high speed.

However, in the conventional group type Wisok, only the lower semicircular group helps the normal circulation of the working fluid, but the siphon group constructed by the tube 6 and group group 3 according to the present invention has a cross section of the inner wall of the heat pipe. The hydraulic fluid is held in both the upper and lower parts of the shape, and the synergistic effect of capillary action and siphon action allows the hydraulic fluid to circulate at high speed and in large quantities.

This means that even at high temperatures, a larger amount of thermal energy can be transferred at a higher speed without easily causing the dry-up phenomenon. It is estimated that it is possible to secure at least twice the amount of heat transfer compared to a pipe.

This can be said to be a new heat pipe structure that breaks through the so-called capillary limit of heat pipe characteristics.

(5) Since there is no splash limit, it can be used up to higher temperatures than ordinary heat pipes, increasing the amount of heat transferred.

In other words, the working fluid that is circulating at high speed within the group and the vapor of the working fluid that is moving at an extremely high speed in the opposite direction are completely separated by the tube 6, so that the flow of the working fluid has little resistance due to the vapor flow. Therefore, there is no possibility that the working fluid will be splashed by the steam flow and returned to the heat dissipation part, thereby causing a splash limit that degrades the performance of the heat pipe.

The speed of vapor movement occurs when the temperature of the heat supply part is high, the entire container of the heat pipe is active, and the temperature difference between it and the heat dissipation part is large.

The maximum heat transfer amount of the heat pipe increases as the temperature of the heat supply section increases, so the heat pipe installed in the screw according to the present invention has no splash limit due to the action of the tube 6, so it can be used at higher temperatures. Therefore, the maximum amount of heat transfer also increases.

The effect of this tube 60 not only overcomes the capillary limit as described above, but also breaks the droplet limit, and can be said to be an epoch-making structure as a heat pipe.

An enlarged view of these group type uiseok 3 and tube 6 is shown in FIG.

In the drawing, reference numeral 7 denotes a heat insulating layer, which is constructed by covering the outer periphery of the heat pipe corresponding to the compression section C, material supply section D, and drive section EKU in the screw of the present invention with a heat insulating material.

The functions and effects of the heat insulating layer are as follows.

(1) Since the above-mentioned sections C, D, and E are sections where temperature rise is undesirable, heat transfer from the heat hype is prevented and the heating efficiency of the heat pipe is prevented from decreasing.

(2) When cooling part A or parts A and B, the working fluid flowing back into the heat pipe in this part prevents the cooling efficiency of the heated heat pipe from decreasing depending on the temperature of parts C, D, and E. .

As shown in the drawing, the insulation layer is thin, so the insulation effect cannot be said to be sufficient, but the heat transfer of the heat pipe has extremely fast vapor transfer speeds and working fluid movement speeds, and is adiabatic, and the transfer and reception of thermal energy is large. Part of this is done by latent heat during evaporation and condensation.

This is done by the unique operation of heat pipes such as
, D, E and the heat pipe can have a great effect just by significantly reducing the speed of movement.

On the other hand, if there were no such heat insulating parts, intense heat exchange unique to heat pipes would occur between parts C, D, and E and the heat pipe, and the effect of the extrusion screw according to the present invention would be reduced by half. It is an unnecessary part.

There is a possibility that heating or cooling sections C, D, and E may even cause a major problem.

The heat insulating layer plays an important role in preventing such dangerous heat transfer and converting it into a heat transfer based on extremely slow heat conduction.

In addition, heating and cooling to the extent of heat loss of this heat pipe is a necessary amount of thermal energy and is rather useful if it is carved into parts C and D of the above-mentioned parts C, D, and E. It is.

As described above, the effect of the combination structure of the group type wick 3 and the hydraulic fluid dispersion wick 4 provided on the inner wall of the heat pipe container at the position corresponding to the measuring part A or the measuring part A and the melting part B, and similar combinations. Effects of the liner 50 for improving thermal conductivity provided between the outer periphery of the heat pipe and the screw main body corresponding to part A or parts A and B, compression part C. Effects of the combination structure of the group type wink 3 and the working fluid evaporation prevention tube 6 provided on the inner wall of the container at the positions corresponding to the material supply section D and the drive section E, C.
The effect of each individual partial structure on the performance of the plasticox extrusion screw according to the present invention, such as the effect of the heat insulating layer provided on the outer periphery of the heat pipe at the positions corresponding to parts D, D and E, will be explained in detail. It's here.

The cross-sectional structures of these parts are shown in FIGS. 2 to 5.

Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is taken along line B-B.
4 is a cross-sectional view taken along lines C-C and D-D, and FIG. 5 is a cross-sectional view taken along line F-F.

The screw for plastics extrusion according to the present invention is composed of a combination of various new structures that have the functions and effects described in detail above, so when it is installed in the cylinder of an extruder or injection molding machine to carry out molding work. Overall, it exhibits the following outstanding effects.

(1) Extremely good heating efficiency enables significant energy savings.

In an extrusion device to which the extrusion screw according to the present invention is applied, heating of the plastic is performed from inside the screw, so the heating energy is directly applied to the plastic from the screw surface and at the same time as the stirring action and compression action on the screw surface. Supplied inside the material.

Therefore, there is no opportunity for heat loss to occur, so heating efficiency is extremely good.

In contrast, the conventional cylinder heating method has a heat dissipation air layer for emergency heat dissipation through the thick metal layer on the cylinder wall, and heats through the thick metal layer that serves as a heat storage tank, so the heat conduction distance is long. , and the thermal resistance along the way is large, resulting in large heat loss.

Also, the surface area of the heat source is large, and therefore heat loss is large.

Furthermore, since heat is supplied to the plastic only on the inner wall surface of the cylinder, the heat transfer area is small.

Conventional extruders, which required a large amount of heating energy for these reasons, had a cylinder inner diameter of 65 mm and a heat source capacity of 1.
The power consumption during operation was approximately 5 KW/hour for extruding vinyl chloride.

The calculated power required to melt vinyl chloride is 3κV.
It can be seen that there is a lot of heat loss since it is 1 κW/hour to 1.5 κW/hour during normal operation.

In the device of the present invention, which cuts the material and heats it directly on the screw surface, there is almost no heat loss, so the energy consumption is 2 to 3 K in terms of electricity! / hour is enough.

It is possible to install a 25 mm diameter heat pipe inside a 65 mm diameter extrusion screw, and when applying various new structures according to the present invention to the heat pipe, the output power is 4KW to 6KW, which is twice that of the conventional heat pipe. of heat can be supplied to the measuring section and melting section of the screw.

Therefore, in this device, the cylinder external heat source has a small capacity and is used only as an auxiliary heat source to shorten the preparation time for starting work or restarting after stopping, and as an auxiliary heat source to provide a slight temperature difference to each part of the cylinder. This is a good thing and can lead to great labor savings.

Additionally, as will be explained later, this device eliminates the need for heat radiation from the outer wall of the cylinder, and as a result, the surface area of the cylinder's exterior, which had previously been enlarged, can be greatly reduced, making it possible to further reduce heat loss. .

(2) It has extremely good thermal responsiveness in accordance with changes in temperature conditions necessary for ceremonial work, so time loss and material loss can be greatly reduced.

As mentioned above, temperature adjustment is performed directly by carving into the inside of the material through the screw surface, so the temperature of the material can be changed in an extremely short time due to the rapid thermal response speed of the heat pipe inside the screw.

Traditionally, this type of temperature change takes 20 to 30 minutes using a 65mm extruder.
During this time, the material inside the cylinder would also undergo thermal deterioration resulting in loss, but with the device of the present invention, it is possible to change the temperature conditions and resume work within 5 minutes. Thermal degradation of the material over time is negligible.

(3) Since the time required for the screw temperature to stabilize, which is most important in extrusion molding and injection molding, is extremely short, it reduces time loss and material loss due to work preparation time and restart time after stopping. Quality can be improved.

In the case of a cylinder heating system in an extrusion device or the like, it takes a long time to reach a predetermined temperature inside the screw.

With a 90 mm diameter extruder, it takes 6 to 8 hours to reach the specified temperature inside the screw after heating starts, and with a 65 mm diameter extruder, it takes 4 to 8 hours to reach the specified temperature inside the screw.
It takes between 6 hours and 6 hours.

In actual work, this long time cannot be wasted, so the actual situation is to start work in about half that time. Ru.

Work is usually carried out with the expectation that quality will be unstable for several hours after work begins.

However, in the apparatus according to the present invention, since heating is carried out from inside the screw, the predetermined temperature condition is reached in about 15 minutes at the start of work and about 5 minutes at the time of restarting work.

This is a great advantage in terms of reducing time loss and material loss, similar to the quick thermal response mentioned in the previous item (2).

In addition, in order to eliminate such losses in conventional equipment, the present invention can be applied to continuous work for long periods of time, including night work, which is carried out in actual work, and to continue heating the equipment during work stoppages. Considering the fact that this is no longer necessary in the device, it is considered that the extrusion screw according to the present invention makes an extremely large contribution from the standpoint of energy saving.

(4) The efficiency of heat radiation cooling from the device is extremely high and rapid, so various effects can be achieved.

In the extrusion screw according to the present invention, the heat transfer capacity of the heat pipe is doubled compared to the conventional one, and the extrusion screw has a diameter of 25 mm.
Even a heat pipe can reach 4KW to 6KW, so effects that cannot be obtained by simply inserting a normal heat pipe into the screw can be obtained.

(1) During heat dissipation, as in the case of heating, thermal energy is directly absorbed from the plastic material and is emitted directly to the outside of the device via the heat pipe without waste and extremely quickly.

Therefore, even if the temperature of other parts of the device is still high, the plastic material has already been completely cooled, and the cooling effect is tremendous.

Further, during cooling, the screw itself, which protrudes spirally on the screw body, acts as a fin to absorb heat from the plastic material.

Since the cooling effect is thus large, a cylinder cooling structure is completely unnecessary in this device.

Even when used in conjunction with a conventional cooling structure, each metal layer on the outer wall of the cylinder with a large heat capacity is cooled by a cooling fan, etc., and by the time the cooling effect reaches the plastic material, the plastic material is removed from the screw. As a result, cooling is completed and the cylinder external cooling device ends up being useless.

The external structure of the extruder cylinder, which no longer requires a cooling structure or a dog-sized heat source for heating, is extremely simple and compact, the heat capacity is small, and the heat dissipation area is reduced by about half, which reduces the heat insulation effect of the heat insulation layer. The thermal energy required to maintain the working temperature in this device can be synergistically reduced.

For example, in the case of a 65mmφ extruder, conventional extruders require electric heat of 12κW to 15KW as a heat source for heating the cylinder, but in the case of applying the present invention, no external heat source is required at all, but the maximum But 2K! It is sufficient to use only the heat source for setting the temperature difference depending on the degree.The heat source for heat pipe heating is 4KW to 6κW, and the total required power source is 4KW to 6KW.
8) It becomes CW, and its energy saving effect is extremely large.

(11) As mentioned above, since the plastic material itself can be rapidly cooled directly faster than other parts, the long cooling time that was required at the end of a temporary stoppage of work can be completed in a few minutes.

Furthermore, the phenomenon of fusion of plastics arranged in the measuring section and melting section on the screw surface, which occurs at such times, is eliminated, and cleaning of the screw becomes unnecessary.

The overall reduction in lost time resulting from these results has a great effect on reducing production costs.

(110) The cooling of the remaining material in the cylinder in the case described above is so rapid and complete that the remaining material can withstand reuse without thermal deterioration.

It is also possible to leave it in the cylinder until the next work and reuse it.

The effects of the present invention are extremely valuable for factories that produce a wide variety of products in small quantities.

(5) Adiabatic extrusion work becomes extremely easy.

The adiabatic extrusion method, which uses frictional heat between the material, the screw surface, and the inner wall of the cylinder to perform high-speed extrusion without external heating, has not been widely used because it has been difficult to control the temperature.

When using the extrusion screw according to the present invention, excess heat generation can be easily radiated, and the temperature of the material can be easily controlled, making adiabatic extrusion work extremely easy.

As detailed above, the extrusion screw according to the present invention saves energy, improves quality, and operates with the help of the heat pipe installed in its center, which has excellent performance that is twice that of a conventional heat pipe. This brings about innovative effects in extrusion molding work and injection molding work, such as improved molding efficiency.

Among the effects of the present invention, the most important effect is the siphon of a large number of pipes formed by the group type pipes provided on the inner wall of the container and the tubes for preventing evaporation of the working fluid provided closely on the inner periphery thereof. As a result of this action, the reflux rate and amount of the working fluid are increased, thereby greatly increasing the heat transfer capacity.A structure for ensuring this effect is shown in FIG. 7.

In the drawing, the diameter of the hydraulic fluid evaporation prevention tube 6 is slightly reduced at both ends, and there is a hydraulic fluid reservoir 6'.
has been formed.

If configured in this way, the hydraulic fluid will accumulate in this area during its circulation cycle, and when the group of pipes formed by the group and the tube sucks the hydraulic fluid through a siphon action, the hydraulic fluid vapor will be sucked in. To prevent.

Air bubbles entering the siphon destroy the continuity of siphon action and capillary action and reduce the ability to transfer hydraulic fluid, and it is considered important to prevent this.

The hydraulic fluid reservoir 6' can also prevent hydraulic fluid from overflowing and entering the steam passage.

If the working fluid enters the steam passage, the strong flow of steam will cause the working fluid to be blown back into the heat radiating section.
This creates a short-circuit circulation cycle of the working fluid, which deteriorates the characteristics of the heat pipe.

When the extrusion screw according to the present invention is used horizontally, the siphon action also works due to the difference in the head of the working fluid between the evaporation section and the condensation section, but it is more powerful when the extrusion screw is slightly tilted and gravity is used to assist. can be made to act.

Therefore, when carrying out work with the extrusion screw according to the present invention installed in a cylinder, when supplying thermal energy into the screw, the metering section side of the screw should be placed at a higher position than the temperature control side. When discharging thermal energy, the effects of the present invention can be more effectively enjoyed by operating the device with the measuring section side slightly inclined to a lower position than the temperature adjusting side.

As a practical method for this, an extruder or an injection molding machine with adjustable cylinder and screw inclinations may be used, or a bed for installing the machine may be of an adjustable inclination type.

However, since this inclination is to ensure the siphon effect of the working fluid return path of the heat pipe, a large inclination angle is unnecessary and an angle of 3° to 5° is considered to be sufficient.

When using the extrusion screw according to the present invention in an inclined manner, care must be taken to ensure that the height relationship between the measuring section side and the temperature control side is not incorrectly used.

If used incorrectly, the working fluid will flow back against gravity, resulting in a significant reduction in heat transfer capability.

Another point to be noted is that when used horizontally, it must be maintained horizontally without tilting to either side.

In other words, when the cylinder temperature and the screw temperature are automatically adjusted to predetermined temperatures, the evaporation section and condensation section of the working fluid frequently alternate with each other. Since it is not practical to change the direction of inclination, it should be kept horizontal when used.

In addition, the amount of heat supplied and the amount of heat discharged when maintaining the temperature at a predetermined temperature are not so large, and the amount of heat transferred can be small, so there is no need to increase the heat transfer capacity by tilting the screw.

When the diameter of the screw in the extrusion screw according to the present invention is small, it may be impossible to insert a heat pipe with a sufficient amount of heat transfer into the screw.

Also, when using nylon-based or Teflon-based extruded materials,
The extremely high melting temperature makes it impossible to use water as a working fluid.

The range of water usage is approximately 240°C, and as a countermeasure, if you use a high-temperature hydraulic fluid that can withstand 300°C, such as Therm-S (trade name), the heat transfer capacity will be reduced to a fraction of that due to the lack of latent heat. be.

Furthermore, in the case of nylon, Teflon, etc., the coefficient of friction is small and the viscosity after melting is extremely low, so it is impossible to utilize frictional heat.

In such a case, it becomes impossible to supply a sufficient amount of heat using the heat pipe alone.

In such a case, the basic structure of the extrusion screw according to the present invention can be utilized and the thermal conductivity improving liner 5 can be used as an auxiliary heat source in order to thermally efficiently process plastic materials by heating from inside the screw. It is preferable that the heating is supported by a heat pipe.

In this case, methods include a structure in which a heater is inserted into the liner 5, a method in which a cylindrical heater is inserted between the outer periphery of the liner and the main body of the screw, and the like.

Of course, the power line for these is 300'C.
It is necessary to use a super heat-resistant wire that can withstand temperatures of up to 350° C. for a long time, and this power wire is led out of the screw along the insulation layer 7.

When the present invention is applied and implemented in this manner, there are the following effects and points to be noted in use.

(1) When heating the screw using both the auxiliary heat source of the liner for improving thermal conductivity and the heat pipe, it is necessary to always maintain the temperature of the temperature adjustment section F at a higher temperature than the temperature of the liner.

If the F section temperature is lower than the liner temperature, due to the unique performance of the heat pipe, the heat from the auxiliary heat source will immediately flow downward through the heat pipe and be exhausted as heat.
The heat applied to the heat pipe will not be able to heat the screw.

(2) Due to the above-mentioned properties, the applied embodiments described above have the effect of enabling excellent balancing control and precise and accurate temperature control.

That is, by keeping the heat supply level from the liner's auxiliary heat source constant and adjusting the F section temperature, or by keeping the F section temperature constant and adjusting the heat supply amount from the liner's auxiliary heat source. By either method of adjustment, it is possible to precisely control the screw temperature.

In either case, this is temperature control based on the positive and negative balance between heating by the auxiliary heat source and exhaust heat by the heat pipe,
The response speed is much faster than temperature control based solely on adjusting the amount of heating heat, and temperature control with much less variation is possible.

Note that the heat insulating layer 7 provided around the heat pipe does not necessarily mean a layer formed by covering with a heat insulating material.

As an applied example, the heat pipe insertion hole in the center of the screw body is made as large as possible to form a space between the inner wall and the outer wall of the heat pipe, and the air in this space is exhausted. This may be used as a heat insulating layer by creating a high vacuum state.

In this case, the heat loss from the C, D, and E sections of the heat pipe or the heat loss from inside the C, D, and E sections of the screw is only radiant heat dissipation between the two, and the heat insulation is greatly improved.

In this case, it is necessary to completely airtightly seal the space between the screw main body and the heat pipe at the end of section F.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention, in which Fig. 1 is a partially cutaway side view, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Fig.
The figure is a sectional view taken along the line B-B in Figure 1, and Figure 4 is a cross-sectional view taken along the line C-C in Figure 1.
5 is a sectional view taken along line F--F of FIG. 1, FIG. 6 is a partially enlarged sectional view, and FIG. 7 is a partially enlarged longitudinal sectional view. 1...Screw main body, 1'...Screw root, r...Screw 2...
...Container, 3...Group type wick,
4...Wick for dispersing working fluid, 5...
Liner for improving thermal conductivity, 6...Tube for preventing evaporation of working fluid, 7... Heat insulation layer.

Claims (1)

[Scope of Claims] 1. In a plastics extrusion screw used in an energy-saving plastics extruder or injection molding machine, which adjusts processing conditions from the inside by increasing or decreasing the thermal energy inside the screw using a heat pipe, A heat pipe insertion hole is cut in the center of rotation, concentrically with the outer circumference of the screw, from the end on the screw driving part side to near the end on the metering part side, and the heat pipe inserted into the insertion hole is The pipe is installed in the measuring section of the screw, or in the measuring section and the melting section, in such a way that it has good heat conduction to the screw body, and in other parts of the screw, it is thermally insulated by a heat insulating layer. A part of the heat hive is exposed to the outside of the screw, and this part is heated or cooled to form a temperature control section that adjusts the screw temperature. In the entire length of the group type wick, there is a circumference inscribed in the group at a position corresponding to the measuring part or the measuring part and melting part of the screw, and a position corresponding to the temperature adjusting part of the heat pipe. A thin-walled working fluid dispersion wick, such as a roughly formed braided tube made of thin metal wire, a wire mesh tube, or a coarse sintered compact tube, is closely formed on the top of the wick, and the other parts of the group type wick are A plastics extrusion characterized in that a thin-walled tube is closely lined on the inscribed circumference, and the thin-walled tube is made of a material that does not permit penetration or permeation by the working fluid and its vapor. Screw for. 2% In the screw for extruding plastics according to claim 1, the screw body and the outer periphery of the heat pipe are in close contact with each other at a position corresponding to the plastics measuring part or the measuring part and the melting part to conduct heat. The liner is a cylinder made of a metal with good thermal conductivity such as copper or aluminum, or a heat pipe or a hollow liner made of a metal with good thermal conductivity and a heat pipe. A plastics extrusion screw characterized by being cylindrical. 3. The screw for extruding plastics according to claim 1, wherein the end of the impermeable tube provided inscribed in the group type wick has a reduced diameter. Extrusion screw. 4. In the screws for extruding plastics according to any one of claims 1 to 3, when these extrusion screws are installed in the cylinder of the molding machine body and operated, thermal energy is introduced into the screws. When supplying heat, the terminal of the measuring section of the screw is placed at a higher position than the temperature adjusting section, and when discharging thermal energy from within the screw, the terminal of the measuring section of the screw is kept at a lower position than the temperature adjusting section by tilting the screw. A screw for extruding plastics, characterized in that when maintaining a constant temperature, the screw is maintained horizontally during extrusion molding work or injection molding work. 5. In the screw for extruding plastics according to any one of claims 1 to 4, the heat-insulating layer provided on a part of the outer periphery of the heat pipe is replaced with a heat-insulating material covering structure, and a high-vacuum hollow heat-insulating structure is used. Screw for extruding plastics 6, characterized in that in the screw for extruding plastics according to claim 2, the liner for improving thermal conductivity has a structure that itself has a heating function as a heat source. Features: Screw for extruding plastics.