JP2008126142A - Closed type kneader and shear mixing measure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable shortening of shear mixing time of a material to be kneaded such as rubber or sulfur. <P>SOLUTION: A closed type kneader comprises an oil hydraulic cylinder and a piston mechanism of vertically moving a ram among a lower limit position for closing a shear mixing chamber, a first upper limit position for charging the material to be kneaded, and a second upper limit position for cutting back a shear mixing material during shear mixing. A stroke between the lower limit position and the second upper limit position is set shorter than a stroke between the lower limit position and the first upper limit position to shorten a shear mixing loss time generated due to the cutback of the shear mixing material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a closed kneading machine and a kneading method for producing a compounded rubber or the like by kneading a material to be kneaded such as rubber or sulfur as a material for a tire or the like.

  In order to impart desired physical properties to the vulcanized rubber material constituting the tire, etc., when kneading the raw materials such as rubber, the rubber molecules are cut to plasticize and refine the raw material rubber. It is necessary to uniformly disperse additives and compounding chemicals such as sulfur. Conventionally, for this kneading, a closed kneading machine is used which is excellent in kneading characteristics of the material to be kneaded and can obtain a kneaded material having good dispersibility.

FIG. 4 is a schematic sectional view showing an example of this conventional closed kneader (Banbury mixer). 4A shows a state where the ram (floating weight) is raised to the upper limit position of the stroke, and FIG. 4B shows a state where the ram is lowered to the lower limit position of the stroke.
As shown in the figure, the hermetic kneader 10 is disposed in a casing 11, a kneading chamber 12 formed therein, and a kneading chamber (sealed portion) 12, and is opposite to each other by a motor (not shown). Two parallel rotors 13 that rotate in the direction, a charging-side hopper 14 that is provided at the top of the casing 11 and communicates with the kneading chamber 12 inside, and a ram (floating weight) 15 that serves as a weight that moves up and down inside thereof. And a piston / cylinder mechanism 16 that drives the ram 15 attached to the upper portion of the charging side hopper 14 and integrally connected to the piston rod 29. Further, a drop door 17 that closes the lower opening of the kneading chamber 12 is attached to the lower surface of the casing 11, and a charging port 18 for charging the material to be kneaded is closed on the side surface of the charging side hopper 14. A hopper door 19 is provided.

A material to be kneaded such as rubber or sulfur is charged into the kneading chamber 12 through the charging port 18 by opening the hopper door 19 with the ram 15 raised. Subsequently, the ram 15 descends to seal the kneading chamber 12, and the material to be kneaded is kneaded by the rotor 13 that rotates in it. After completion of the kneading, the drop door 17 is opened and the kneaded material (kneaded rubber) is taken out from the lower end of the casing 11.
In the conventional closed kneader 10, the kneaded material in the kneading chamber 12 is pressed by the ram 15 during kneading to suppress the kneaded material from being lifted up.

  By the way, in the closed kneader 10, if the rotor 13 continues to rotate in the kneading chamber 12, the kneaded material in the vicinity of the circumferential surface of the rotor 13 is rotated with the rotor 13, making it difficult for kneading to be performed uniformly. Therefore, the ram 15 is reciprocated normally about twice during one kneading step. That is, as shown in FIG. 4A, after the ram 15 is raised to release the kneaded material being kneaded and squeezed out of the kneading chamber 12, the ram 15 is lowered and the kneaded material is removed as shown in FIG. 4B. The kneaded product is switched (or repositioned) by pushing it back into the kneading chamber.

The vertical movement of the ram 15 during kneading is performed by the piston / cylinder mechanism 16. In the conventional closed kneader 10, the piston / cylinder mechanism 16 is driven by air pressure.
However, when air pressure is used to drive the piston / cylinder mechanism 16, the air that is the pressure medium is compressible. Therefore, even if the ram 15 is stopped in the middle of its stroke, the inertial force and gravity of the ram 15 Under the action, the air as a medium cannot be stopped at an accurate position by repeatedly compressing and expanding on both sides of the piston.

  Therefore, the upper stop position of the ram 15 in the case where the pneumatic piston / cylinder mechanism 16 is used as the driving mechanism of the ram 15 as in the prior art must be limited to the mechanical upper limit position. Is limited between the upper limit and the lower limit position in contact with the kneaded material. That is, conventionally, even when the ram 15 is simply reciprocated up and down to change the rubber during kneading, the ram is once moved to the mechanical upper limit position in FIG. Raised and then lowered again.

  In this way, when the ram 15 is separated from the kneaded product during the kneading and releases the pressing force acting on the kneaded product, the kneaded product is squeezed upward and the kneading does not proceed. Therefore, the time for the ram 15 to move away from the kneaded material, that is, the time for the ram to move up and down, is preferably as short as possible so long as the kneaded material can be turned over. However, when a piston / cylinder mechanism using pneumatic pressure is used for the vertical movement of the ram, as described above, the stroke of the vertical movement of the ram cannot be adjusted, and the time cannot be shortened.

Therefore, it is conceivable to set the stroke of the ram 15 to be short. However, a material to be kneaded such as rubber or sulfur is opened in the state where the ram 15 is raised and the hopper door 19 is opened to enter the kneading chamber 12 from the inlet 18. If the ram 15 has a short stroke for charging, the ram becomes an obstacle to charging when the material to be kneaded is charged from the charging port, and the charging cannot be performed well. Therefore, the stroke of the vertical movement needs to be a certain length or longer so that the ram at the upper limit position does not hinder the charging of the material to be kneaded, and the stroke cannot be shortened unnecessarily.
JP 2005-103897 A

  The present invention has been made in view of the above problems in the conventional kneading machine, and is capable of arbitrarily adjusting the vertical movement stroke of the ram in the kneading machine so as to reciprocate the ram up and down during the kneading. To reduce the kneading loss caused by raising the ram, and thus to shorten the kneading time.

The invention of claim 1 includes a kneading chamber, a rotor arranged in the kneading chamber and rotating in opposite directions, a ram for sealing the kneading chamber, and an inlet for charging the material to be kneaded into the kneading chamber. A closed kneading machine, wherein a first stroke between a lower limit position for sealing the kneading chamber of the ram and a first upper limit position for feeding the material to be kneaded, and for switching the kneaded material during kneading. A hydraulic drive mechanism that moves up and down by a second stroke between the lower limit position and the second upper limit position, wherein the second stroke is set shorter than the first stroke.
According to a second aspect of the present invention, in the hermetic kneader according to the first aspect, the hydraulic drive mechanism includes a piston and a cylinder that are hydraulically driven, and the length of the second stroke is adjustable. Features.
The invention of claim 3 is a kneading method for kneading with a rotor rotating in opposite directions in a closed kneading chamber, the step of placing a ram at a first upper limit position and charging the material to be kneaded; Lowering to the lower limit position and sealing the kneading chamber, and switching the kneaded material by reciprocating the ram with a second stroke shorter than the first stroke between the first upper limit position and the lower limit position during kneading And a step of performing the process.
According to a fourth aspect of the present invention, in the kneading method according to the third aspect, the length of the second stroke is adjustable.

According to the present invention, the ram for switching the kneaded material during kneading is more than the first stroke between the maximum upper limit position when the material to be kneaded is charged and the lower limit position where the ram seals the kneading chamber. The second stroke of the reciprocating motion is set short to reduce the time for the ram to leave the kneaded product during kneading.
In addition, the second stroke can be set arbitrarily, so that the second stroke is minimized.

  According to the present invention, since the stroke of the ram can be freely adjusted, the ram lifting stroke performed during kneading for switching the kneaded product can be set to the minimum length necessary for switching the kneaded product. The kneading loss that occurs as the ram is pulled up can be reduced, and the time for the kneading process can be greatly shortened compared to the conventional method.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a side sectional view of a closed kneader according to an embodiment of the present invention.
The closed kneader 10 'according to the present embodiment is basically the same as the conventional one already described, and the same portions are denoted by the same reference numerals.
That is, two rotors 13 that rotate in reverse to each other are arranged in the kneading chamber 12, and after a material to be kneaded such as rubber is put into the kneading chamber 12, the ram 15 is lowered to seal the kneading chamber 12, and inside it. Kneading.

  Here, unlike the conventional kneading machine 10, the closed kneading machine 10 ′ according to the present embodiment uses hydraulic pressure for the piston / cylinder mechanism 16 ′ that operates the ram. Since the working fluid that is the working medium of the piston / cylinder mechanism 16 'is incompressible, the piston does not move due to the inertial force or gravity of the ram, so the ram can be moved to any position. Can be stopped. As the piston / cylinder mechanism 16 'used here, for example, a conventionally known hydraulic piston / cylinder mechanism may be used.

FIG. 2 is a diagram schematically showing the principle of a hydraulic system used in the ram drive piston / cylinder mechanism of the hermetic kneader of this embodiment.
As shown in the figure, this hydraulic system is provided with ports 21 and 22 for entering and exiting a working fluid, for example, working oil at both ends, a cylinder 20 containing a piston 16 therein, and a motor 23 driving a hydraulic source. The hydraulic pump 27, the hydraulic oil storage tank 28, the switching valve 24, the pipes L1 to L4 that connect the elements or parts of the hydraulic system to each other via the switching valve 24, and the control device that controls the switching valve 24. It consists of 25.

  In the above hydraulic system, when the switching valve 24 is switched and the port 22 and the pipeline L1 are connected to the pipeline L3 and the pump 27 side, and the port 21 and the pipeline L2 are connected to the pipeline L4 and the storage tank 28 side, The piston 16 moves to the right (actually upward), and the ram 15 integrally attached to the piston rod 29 of the piston 16 also moves upward. When the ram 15 reaches the upper limit position (upper position in the figure), the switching valve 24 is switched to shut off the ports 21 and 22 to hold the ram 15 in that position, and the material to be kneaded is charged from the charging port 18.

Subsequently, when the switching valve 24 is switched and the port 21 and the pipe line L2 are connected to the pump 27 via the pipe line L3, and the port 22 and the pipe line L1 are connected to the storage tank 28 via the pipe line L4, the piston is left The ram 15 is also lowered to the lower limit position (lower position in the figure).
When the ram 15 is lowered to the lower position, the switching valve 24 is switched to shut off the ports 21 and 22 and hold the ram 15 at the stop position.

  When the ram 15 reaches the lower position, the kneading chamber 12 is sealed, and the material to be kneaded is kneaded by the two rotors 13 rotating in opposite directions in the sealed kneading chamber. Thereafter, after a predetermined time has elapsed, the ram 15 is pulled up to switch the rubber that is the kneaded product.

Here, the control device 25 is attached to, for example, a stroke of the vertical movement of the piston 26 inserted into the cylinder 20 based on an operation timing of the switching valve 24 arbitrarily set in advance, and therefore, a piston rod 29 integral therewith, and a lower end thereof. The stroke of the vertical movement of the ram 15 is adjusted.
In the present embodiment, the stroke control of the ram 15 is performed by switching control of the switching valve 24 with a mechanical timer or a software timer function built in the control device 25, or the first (upper stage), A position detection means (not shown) configured to detect the second (middle stage) position and the lower limit position, for example, constituted by a limit switch, a proximity switch, etc., is provided so as to be adjustable, and the position detection means and the control device 25 are electrically connected. It may be performed by connecting to and switching the switching valve 24.

In the present embodiment, the stroke of the ram 15 when the ram 15 is once moved up and down for switching the kneaded material during kneading is more than the stroke when the ram 15 is raised to the upper limit position for charging the material to be kneaded. The reduction in the kneading efficiency by releasing the pressing force of the ram 15 from the kneaded product during the kneading is minimized.
That is, in the kneading machine 10 'of the present embodiment, the reciprocating stroke of the ram 15 at the time of pulling is set shorter than that of the conventional one, and the time for lifting the ram 15 is shortened. Has also greatly improved the kneading efficiency.
Next, this point will be described in comparison with the conventional kneader 10.

FIG. 3 is a diagram showing the position of the ram 15 of the kneader as time passes, with the vertical axis representing height: h and the horizontal axis representing time: t. FIG. 3A is a view showing the position of the ram of the conventional kneader, and FIG. 3B is a view showing the position of the ram of the kneader of this embodiment.
The ram 15 is pulled up to the upper limit position (upper position in the figure), the material to be kneaded is put in that state, and then the ram 15 is lowered to the kneading chamber 12 to start kneading. In the example of FIG. 3, 11 seconds have passed so far. Then, after kneading for 9 seconds, the ram 15 is pulled up to switch the kneaded material.

As apparent from FIGS. 3A and 3B, the movement of the ram 15 so far is the same in the conventional kneading machine 10 and the kneading machine 10 ′ of the present embodiment.
Here, regarding the lifting stroke of the ram 15, in the conventional kneader 10, as shown in FIG. 3A, the ram 15 is once again raised to the upper limit (upper stage in the figure) when the material to be kneaded is placed. On the other hand, in the kneader 10 ′ of the present embodiment, as shown in FIG. 3B, as a result of adjusting the stroke of the ram 15, the half height of the upper position, that is, the stroke is set to the middle stage in the figure. The stroke of the ram 15 is half that of the conventional one.

Therefore, as is apparent from the time (second) scale on the horizontal axis in FIGS. 3A and 3B, the conventional kneader takes about 10 seconds to switch the rubber as the kneaded product. In the kneader of this embodiment, the time is shortened to about 5 seconds.
In the conventional kneader and the kneader of the present embodiment, when viewed in terms of the total time from the start to the end of kneading, the conventional kneader shown in FIG. 3A took 70 seconds. Since the kneading machine of the present embodiment shown in FIG. 5 is completed in 59 seconds, it is shortened by 11 seconds, and in this example, an improvement in productivity of about 15% is recognized.

  Although not shown, if the kneading process is carried out with a cycle time of 120 seconds as in normal rubber kneading, and the ram raising is switched twice during the same cycle time, 5 seconds each. The loss time of 10 seconds in total is reduced, and as a result, productivity can be improved by about 10%.

  As described above, in the embodiment of the present invention, since the stroke length of the piston can be freely set, the piston can be moved up and down with a short stroke for switching the kneaded material such as rubber during kneading. The kneading loss time can be reduced as compared with the conventional one in which the ram 15 can be moved up and down only between the upper limit position and the lower limit position of the piston when the material to be kneaded is charged. Can be shortened.

In the kneader, the one that moves the ram up and down hydraulically is already known (see Patent Document 1).
This kneading machine is equipped with a piston / cylinder mechanism that can operate a ram (floating weight) by using either hydraulic pressure, pneumatic pressure or hydraulic pressure and pneumatic pressure alone or in combination as appropriate. In addition, it is said that optimal kneading is performed by switching only hydraulic pressure or pneumatic pressure or switching between hydraulic pressure and pneumatic pressure at each kneading step.
However, Patent Document 1 does not describe changing the vertical stroke of the ram (floating weight), and also describes moving the ram up and down to change the kneaded material during kneading. It has not been.
Therefore, this closed kneader does not disclose the technical matters of the present invention.

It is a cutaway side view of a closed kneading machine concerning an embodiment of the present invention. It is the figure which showed typically the principle of the hydraulic system used with the ram drive piston and cylinder mechanism of the closed-type kneading machine of this embodiment. It is a block diagram which shows typically the drive system of the ram in a kneading machine. It is the figure which expressed the position of the ram of the kneader as time passed, with the height: h on the vertical axis and the time: t on the horizontal axis. FIG. 3A is a view showing the position of the ram of the conventional kneader, and FIG. 3B is a view showing the position of the ram of the kneader of this embodiment. FIG. 4A is a schematic sectional side view of a conventional hermetic kneader, FIG. 4A shows a state where the ram is at the upper limit position, and FIG. 4B shows a state where the ram is at the lower limit position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 '... Sealing kneader (Banbury mixer), 11 ... Casing, 12 ... Kneading chamber, 13 ... Rotor, 14 ... Input side hopper, 15 ... Ram (floating) (Weight), 16, 16 '... piston / cylinder device, 17 ... drop door, 18 ... inlet, 19 ... hopper door, 20 ... cylinder, 21, 22 ... port, DESCRIPTION OF SYMBOLS 23 ... Hydraulic motor, 24 ... Switching valve, 25 ... Control apparatus, 27 ... Hydraulic pump, 28 ... (Working oil) storage tank, 29 ... Piston rod.

Claims (4)

A closed kneading machine comprising a kneading chamber, a rotor arranged in the kneading chamber and rotating in opposite directions, a ram for sealing the kneading chamber, and an inlet for charging the material to be kneaded into the kneading chamber. ,
A first stroke between a lower limit position for sealing the ram in the kneading chamber, a first upper limit position for charging the material to be kneaded, and a lower limit position and a second upper limit for switching the kneaded material during kneading. A hydraulic drive mechanism that moves up and down with a second stroke between positions,
The hermetic kneader characterized in that the second stroke is set shorter than the first stroke. In the closed kneader according to claim 1,
The hermetic kneader characterized in that the hydraulic drive mechanism comprises a hydraulically driven piston and cylinder, and the length of the second stroke is adjustable. A kneading method for kneading with a rotor rotating in opposite directions in a closed kneading chamber,
Placing the ram at the first upper limit position and charging the material to be kneaded;
Lowering the ram to the lower limit position and sealing the kneading chamber,
A step of switching the kneaded product by reciprocating the ram with a second stroke shorter than the first stroke between the first upper limit position and the lower limit position during kneading,
A kneading method characterized by comprising: In the kneading method according to claim 3,
The kneading method, wherein the length of the second stroke is adjustable.

Images