JP2003311816A - Measuring method for deflection of screw of screw type extruder, and screw type extruder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method for the deflection of the screw of a screw type extruder, capable of estimating the abrasion quantity of the leading end surface of a screw blade and the inner peripheral surface of a barrel hole without detaching the draw-out of the screw and the detachment of a barrel, and the screw type extruder. <P>SOLUTION: In the measuring method for the deflection of the screw, the distance up to the leading end surface of the screw blade of the screw 12 during the operation of the screw type extruder 10 is measured using the eddy current type displacement sensor 14 provided to the barrel 11 of the screw type extruder 10. Further, the screw type extruder equipped with the barrel 11 and screws 12 and 12' is equipped with the sensor holding body 13 provided to the barrel 11 so that the leading end surface constitutes a part of the inner peripheral surface of the barrel hole 11b, the eddy current type displacement sensor 14 held to the sensor holding body 13 to detect the distance up to the screw 12 during operation and a sensor output processing means 15 for processing the output from the sensor 14 to measure the distance up to the leading end surface of the screw blade. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to estimate the amount of wear between the tip surface of a screw blade and the inner peripheral surface of a barrel hole without pulling out an extruder screw and removing the barrel. TECHNICAL FIELD The present invention relates to a method for measuring a shake of a screw type extruder and a screw type extruder.

[0002]

2. Description of the Related Art A screw type extruder is equipped with a barrel and one or two screws rotatably inserted into a barrel hole (chamber chamber) of the barrel. The material such as resin is kneaded, mixed and extruded while being conveyed. In screw type extruders, the screw axial length L is longer than the shaft diameter D. Generally, the cold extruder for rubber has an L / D value of about 15 and the kneading extruder for resin has an L / D value. Is about 42. For this reason, in the screw type extruder, the deflection of the screw becomes a large value that cannot be mechanically ignored. On the other hand, in the screw type extruder, in order to improve the extrusion efficiency, the gap between the screw blade tip surface (the screw crest) and the inner peripheral surface of the barrel hole is narrow, and is generally set to about 0.1 to 1.0 mm. .

From these facts, in the screw type extruder, the tip surface of the screw blade comes into contact with the inner peripheral surface of the barrel hole at a position other than the screw root portion in the screw axial direction during the extrusion operation, and the tip surface of the screw blade is Or, it is inevitable that the inner peripheral surface of the barrel hole or both of them are worn. In the kneading extruder for resin, although the contact between the screw blade tip surface and the inner peripheral surface of the barrel hole can be reduced by using the molten resin as a lubricant, abrasion still occurs before the resin pellets and powder are melted. It will be. Further, the hard powder mixed in the extruded material, such as industrial carbon, silica, calcium carbonate, etc., also causes abrasion of the tip surface of the screw blade and the inner peripheral surface of the barrel hole. When the degree of wear increases, the amount of extrusion decreases, and the quality of the extruded product deteriorates due to, for example, poor mixing and dispersion, or unmelted material remains due to a decrease in material temperature. If the wear further progresses, water leakage may occur from the jacket hole of the barrel.

Conventionally, as a method of confirming the wear amount, the screw is pulled out from the barrel to the outside of the barrel, the outer diameter of the screw blade is measured, and the wear amount of the screw is confirmed from the difference from the manufacturing size. Also, for the barrel, remove the barrel, measure the inner diameter of the barrel hole,
The amount of wear on the inner peripheral surface of the barrel hole was confirmed from the difference with the manufacturing dimensions.

[0005]

Conventionally, as described above, it is necessary to pull out the screw and remove the barrel in order to confirm the amount of wear of the tip surface of the screw blade and the inner peripheral surface of the barrel hole. However, it took a lot of effort and time.

The present invention has been made in view of the above circumstances, and the amount of wear between the screw blade tip surface and the inner peripheral surface of the barrel hole without pulling out the extruder screw and removing the barrel. It is an object of the present invention to provide a screw runout measuring method for a screw type extruder and a screw type extruder capable of estimating the above.

[0007]

In order to achieve the above object, the present invention employs the following technical means.

According to a first aspect of the present invention, when measuring the runout of a screw rotatably inserted in a barrel hole of a barrel of a screw type extruder, an eddy current displacement sensor provided in the barrel is used to measure the runout of the screw. A screw runout measuring method for a screw type extruder, wherein the distance to the tip surface of the screw blade is measured during operation of the screw type extruder.

According to a second aspect of the present invention, in the method for measuring the screw runout state of the screw type extruder according to the first aspect, a plurality of eddy current displacement sensors are used for the screw to detect the phase of the screw. The feature is that the distances to different screw blade tip surfaces are measured respectively.

According to a third aspect of the present invention, in a screw type extruder having a barrel and a screw rotatably inserted in the barrel hole of the barrel, the tip end surface of the screw extruder is a part of the inner peripheral surface of the barrel hole. A sensor holder provided on the barrel so as to be configured, and held by the sensor holder,
An eddy current displacement sensor that detects the distance to the screw during operation, and a sensor output processing unit that processes the output from the eddy current displacement sensor and measures the distance to the tip surface of the screw blade. Is a screw type extruder.

According to a fourth aspect of the present invention, in the screw type extruder according to the third aspect, the material of the sensor holder is engineering plastic or ceramic.

According to a fourth aspect of the invention, in the screw type extruder according to the third or fourth aspect, there is provided a sensor temperature adjusting means for holding the eddy current displacement sensor at a substantially constant temperature. To do.

According to the screw runout measuring method of the screw type extruder and the screw type extruder according to the present invention, the tip surface of the screw blade during operation of the screw type extruder is used by using the eddy current displacement sensor provided in the barrel. It is possible to estimate the amount of wear between the tip surface of the screw blade and the inner peripheral surface of the barrel hole based on the change over time with the operation of the screw type extruder. As a result, it is not necessary to pull out the extruder screw and remove the barrel, and the labor and time required for maintenance of the screw type extruder can be greatly reduced, and the extruder operating rate can be improved. The eddy current displacement sensor is a sensor that detects a distance (position / displacement of the detection target) made of a conductor to the detection target. In the present invention, the eddy current displacement sensor is adopted because the detection target is a screw and the sensor head is small.

In the screw type extruder according to the present invention, the sensor holding body is provided in the barrel so that the front end surface of the sensor holding body forms a part of the inner peripheral surface of the barrel hole, and the sensor holding body is embedded in the sensor holding body to thereby cause the eddy current. Holds the displacement sensor. In this case, the material of the sensor holder is preferably non-metal so as not to adversely affect the distance detection performance of the eddy current displacement sensor, and it has excellent hardness and strength and is inexpensive and easy to handle. Examples include engineering plastics. From various engineering plastics, one having characteristics such as heat resistant temperature suitable for the extruded material may be selected. In addition, ceramics are mentioned because they are excellent in heat resistance temperature and chemical resistance and have extremely small temperature expansion. In the case of ceramics, the composition having a composition very similar to the inorganic compounding agent contained in the extruded material has an advantage that the influence of abrasion powder from the sensor holder on the product quality can be made extremely small.

In the screw type extruder according to the present invention, which is provided with the sensor temperature adjusting means for keeping the eddy current displacement sensor at a substantially constant temperature, the detection error due to the temperature drift of the eddy current displacement sensor is minimized. Therefore, more accurate measurement can be performed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the configuration of a screw type extruder for carrying out the method for measuring the shake of a screw according to the present invention.

The screw type extruder 10 of this embodiment is
As shown in FIG. 1, it has two barrels and two screws 12 and 12 '. The barrel 11 includes a barrel body 11a and a barrel lid 11c.
And two barrel holes 11b,
11b 'are arranged in parallel so as to communicate with each other in the radial direction and extend in the barrel axial direction, and these barrel holes 11b, 11b' are provided.
The screws 12 and 12 'are rotatably inserted into the respective screws. The barrel body 11a and the barrel lid 11c include
A large number of jacket holes 11d for temperature control medium circulation are provided along the inner peripheral surfaces of the barrel holes 11b and 11b 'to adjust the temperature of the barrel 11 by flowing hot water or oil. Each screw 12, 12 'has two wings.

The barrel lid 11c is provided with a hole which communicates from the outside of the barrel 11 to one barrel hole 11b in the vertical direction in FIG. 1, and the front end of this hole is part of the inner peripheral surface of the barrel hole 11b. The sensor holder 13 made of engineering plastic is fitted and fixed so as to form An eddy current type displacement sensor (eddy current type displacement sensor head) 14 for detecting the distance to the screw 12 is embedded and fixed to the sensor holder 13. In the eddy current displacement sensor 14, the sensor tip portion is brought close to the tip surface of the sensor holding body 13 (the inner peripheral surface of the barrel hole 11b), and the sensor base end portion to which the signal cable is connected is projected from the sensor holding body 13. It is embedded in the sensor holder 13 in this state.

In general, an eddy current displacement sensor has a short detectable distance, and a small eddy current displacement sensor has a detection distance of 10 mm.
Since it is about mm, it is preferable to bring it as close as possible to the detection target. However, forming a part of the inner peripheral surface of the barrel hole 11b by the tip portion of the eddy current displacement sensor 14 means that the screw blade tip surface 12 of the screw 12 is formed at the tip portion.
Since a may contact with a, it is inappropriate in terms of strength. Therefore, the tip portion of the eddy current displacement sensor 14 is positioned close to the tip surface of the sensor holder 13 (the inner peripheral surface of the barrel hole 11b). In the present embodiment, the distance La between the tip of the eddy current displacement sensor 14 and the tip of the sensor holder 13 (the inner peripheral surface of the barrel hole 11b) is
It is set to 1.7 mm.

Further, the sensor holder 13 is provided with a temperature adjusting medium flow passage 13a for flowing a temperature adjusting medium for keeping the eddy current displacement sensor 14 at a substantially constant temperature. In the present embodiment, hot water whose temperature is adjusted to about 50 ° C. is caused to flow from the temperature adjusting water circulating device (not shown) to the temperature adjusting medium flow passage 13a, and then returned to the temperature adjusting water circulating device. The temperature adjusting medium flow passage 13a of the sensor holder 13 and the temperature adjusting water circulating device (not shown) constitute a sensor temperature adjusting means for holding the eddy current displacement sensor 14 at a substantially constant temperature.

The output of the eddy current displacement sensor 14 is the A / D
It is designed to be loaded into the programmed personal computer 15 via a converter or the like. The personal computer 15 processes the output from the eddy current type displacement sensor 14 and processes the output from the eddy current type displacement sensor 14 and the screw 1.
The sensor output processing means is configured to measure the distance from the screw blade tip surface 12a of No. 2 and display the change with time of the operation of the screw type extruder.

Thus, the screw type extruder 10 of this embodiment is constructed. FIG. 2 is a diagram showing an example of the output of the eddy current displacement sensor during operation of the screw type extruder.

The graph of FIG. 2 shows the output of the eddy current displacement sensor 14 at 500 Hz during operation of the screw type extruder.
It is obtained by sampling at a sampling pitch of (2 ms). As is well known, the output of the eddy current displacement sensor 14 increases as the distance to the detection target increases. As shown in FIG. 2, it was observed that the output voltage minimum point was detected 20 times during the time of 1.96 seconds, that is, the distance between the screw 12 and the tip surface 12a of the screw blade 12 was detected by the eddy current displacement sensor 14. To be done. Since the screw 12 has the two blades as described above, the screw blade tip surface 12a passes twice with respect to the eddy current displacement sensor 14, so that the screw 1
It means that 2 has rotated once. The presence of the output voltage minimum point 20 times within 1.96 seconds corresponds to a rotation speed of the screw 12 of 312 times / min, which corresponds to the set screw rotation speed. As a result, the eddy current displacement sensor 14
It was confirmed that the detection by the method was performed reliably.

As can be seen from FIG. 2, except for the distance to the tip surface 12a of the screw blade, for example, the distance to the screw body does not change at all even if the distance changes a little. Since it is within the detection range, the detection accuracy is poor and accurate distance detection cannot be performed. Further, with respect to the screw blade surface, although the detection accuracy is improved as compared with the screw body portion, it is difficult to accurately associate the phase of the screw blade with the output of the eddy current displacement sensor 14. On the other hand, the screw blade tip surface 1 of the screw 12
The distance up to 2a can be detected most accurately, and since the tip of the screw blade has a spherical shape, it is not necessary to consider the phase, which is an excellent detection target position.

FIG. 3 is a graph showing the relationship between the distance between the eddy current displacement sensor and the tip surface of the screw blade at a predetermined time during the operation of the screw extruder, and the number of times the distance is measured. The distance between the eddy current displacement sensor and the tip surface of the screw blade is shown in increments of 0.05 mm.

The graph of FIG. 3 is obtained as follows. The output of the eddy current displacement sensor 14 during a predetermined time (90 seconds in this example) during operation of the screw type extruder is sampled by the A / D converter at a sampling pitch of 500 Hz (2 ms) and is taken into the personal computer 15. . Next, personal computer 1
Reference numeral 5 represents one of the obtained distance detection data corresponding to each output voltage minimum point shown in FIG.
A distance Li between the eddy current displacement sensor 14 and the screw blade tip surface 12a in 90 seconds is obtained. In this case, in this embodiment, the measurement resolution of the distance Li is 0.05 mm. Then, the relationship between the obtained distance Li and the number of times the distance Li is measured is stored in the storage unit, and
It can be displayed on the CRT display of the personal computer 15. Regarding the method of obtaining the distance Li, for example, the range in which the distance Li exists in the distance detection data can be specified from the rotation speed of the screw 12, and thus the distance Li can be easily obtained by obtaining the minimum value in this range. You can ask.

In this way, as shown in FIG. 3, the distance Li between the eddy current displacement sensor 14 and the screw blade tip surface 12a during a predetermined time during the operation of the screw extruder can be measured and measured. From these distances Li,
The closest distance Lmin and the farthest reaction distance Lmax can be obtained. In FIG. 3, the closest distance Lmin between the eddy current displacement sensor 14 and the screw blade tip surface 12a is Lmin.
Is 1.95 mm and the maximum separation distance Lmax is 2.6 m.
m.

Therefore, the distance between the eddy current displacement sensor 14 and the screw blade tip surface 12a of the screw 12 is measured at a predetermined time interval, and the CRT display of the personal computer 15 displays the distance as shown in FIG. By displaying the various measurement results in time series, the closest distance Lmin and the farthest separation distance Lmax between the eddy current displacement sensor 14 and the screw blade tip surface 12a of the screw 12 are shown.
For, it is possible to know the change over time. Then, the closest distance Lmin and the farthest reaction distance Lmax.
The wear amount of the screw blade tip surface 12a of the screw 12 and the inner peripheral surface of the barrel hole 11b can be estimated from the change with time.

That is, the closest distance Lmin between the eddy current displacement sensor 14 and the screw blade tip surface 12a of the screw 12 does not change over time, while the eddy current displacement sensor 14 and the screw blade tip surface 12a are not changed. Maximum separation distance Lmax
Is large, for example, when the closest distance Lmin that was initially Amm does not change as it is, but when the closest separation distance Lmax that was initially A + 2 mm changes in the direction of increasing, the wear of the screw blade tip surface 12a is increased. Is progressing, and it is possible to estimate the amount of change in the maximum separation distance Lmax with time as the amount of wear of the screw blade tip surface 12a. It is estimated that the amount of play of the screw 12 increased as the clearance between the screw blade tip surface 12a and the inner peripheral surface of the barrel hole 11b increased due to the progress of wear of the screw blade tip surface 12a.

In addition, over time, the eddy current displacement sensor 14
When the minimum distance Lmin between the screw blade tip surface 12a and the screw blade tip surface 12a becomes smaller, while the maximum separation distance Lmax between the eddy current displacement sensor 14 and the screw blade tip surface 12a becomes as large as that, for example, first, Amm. When the closest distance Lmin changes in the direction of decreasing, while the distance Amax of A + 2 mm in the first direction changes to increase in the same direction, the inner peripheral surface of the barrel hole 11b is abraded. The amount of change in the closest distance Lmin with time can be estimated as the amount of wear of the inner peripheral surface of the barrel hole 11b. As the wear of the inner peripheral surface of the barrel hole 11b progresses, the tip surface 12a of the screw blade and the barrel hole 11b
It is estimated that the gap between the inner peripheral surface of the screw 12 and the inner peripheral surface of the screw became large and the moving amount of the screw 12 increased.

In addition, over time, the eddy current displacement sensor 14
When the closest distance Lmin between the screw blade tip surface 12a and the screw blade tip surface 12a increases, while the maximum separation distance Lmax between the eddy current displacement sensor 14 and the screw blade tip surface 12a increases, the screw blade tip surface 12a and the barrel hole 11b. It is estimated that the wear of the inner peripheral surface of the is progressing. in this case,
The amount of change over time of the closest distance Lmin can be estimated as the amount of wear of the inner peripheral surface of the barrel hole 11b. In addition, the amount of change in the closest distance Lmin with time and the maximum distance Lmax
Can be estimated as the amount of wear of the screw blade tip surface 12a. In addition, this screw 1
2 and the wear amount of the inner peripheral surface of the barrel hole 11b, the degree of wear of the other screw 12 'and the inner peripheral surface of the barrel hole 11b' can be estimated.

FIG. 4 is a sectional view showing the structure of another screw type extruder for carrying out the screw runout measuring method according to the present invention. Here, the difference from the screw type extruder shown in FIG.
The eddy current type displacement sensors 14 and 24 are provided, and the screw 1
2 is that the distance to the tip surface of the screw blade having a phase difference of 90 ° is measured. Except for this point, it has the same configuration as the screw type extruder shown in FIG. Therefore, the same or substantially the same parts as those shown in FIG. 1 are designated by the same reference numerals.

That is, as shown in FIG. 4, the barrel 11
A hole is provided on one side wall of the barrel 11 from the outside of the barrel 11 to the one barrel hole 11b in the left-right direction in FIG. 4, and the tip surface forms a part of the inner peripheral surface of the barrel hole 11b. As described above, the sensor holder 23 made of engineering plastic is fitted and fixed. An eddy current displacement sensor 24 for detecting the distance from the screw 12 is embedded and fixed to the sensor holder 23.

As described above, the eddy current type displacement sensor 1 shown in FIG.
In addition to 4, the eddy current displacement sensor 2 provided in the left-right direction
4 is provided. Then, as shown in FIG. 5, with respect to each of the two threads of the screw 12, the tip surface of the screw blade reaches one of the eddy current displacement sensors 14 and at the same time as the other eddy current displacement sensor 24. The two eddy current displacement sensors 14 and 24 are arranged so that the tip end surface of the screw blade at a portion having a phase difference of 90 ° from the tip end surface of the screw blade reaches. Reference numeral 23a denotes a temperature adjustment medium flow passage of the sensor holder 23. Hot water whose temperature is adjusted from a temperature adjustment water circulation device (not shown) is caused to flow into the temperature adjustment medium flow passage 23a, and then returned to the temperature adjustment water circulation device. It is supposed to be.

According to the screw type extruder 20 of this embodiment having such a structure, one screw 12 is provided with two eddy current type displacement sensors 14 and 24, and the phase of the screw 12 is 90 °. Since the distances to the different tip surfaces of the screw blades are respectively measured, the tip surfaces of the screw blades of the screw 12 and the barrel holes 11b are compared with those using one eddy current displacement sensor 14.
It is possible to more accurately estimate the wear amount of the inner peripheral surface of the.

[0036]

As described above, according to the screw runout measuring method of the screw type extruder and the screw type extruder according to the present invention, the screw type extruder is used by using the eddy current type displacement sensor provided in the barrel. The distance to the tip surface of the screw blade during machine operation is measured, and the wear amount between the tip surface of the screw blade and the inner peripheral surface of the barrel hole is estimated based on the change over time with the operation of this screw type extruder. be able to. As a result, it is not necessary to pull out the extruder screw and remove the barrel, and the labor and time required for maintenance of the screw type extruder can be greatly reduced, and the extruder operating rate can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a screw type extruder for carrying out a screw runout measuring method according to the present invention.

FIG. 2 is a diagram showing an example of an output of an eddy current displacement sensor during operation of a screw type extruder.

FIG. 3 is a graph showing a relationship between a distance between an eddy current displacement sensor and a screw blade tip surface during a predetermined time during operation of the screw extruder and the number of times the distance is measured.

FIG. 4 is a cross-sectional view showing the configuration of another screw type extruder for carrying out the screw runout measuring method according to the present invention.

5 is a diagram for explaining the positional relationship between the two eddy current displacement sensors and the screw blade in FIG.

[Explanation of symbols]

10, 20 ... Screw type extruder 11 ... Barrel 11
a ... Barrel body 11b, 11b '... Barrel hole 11c
… Barrel lid 11d… Jacket holes for temperature control medium circulation 12, 12 ′… Screw 12a… Screw blade tip surface 13,23… Sensor support 13a, 23a… Temperature control medium flow passages 14,24… Eddy current displacement sensor 1
5 ... Personal computer

Claims (5)

[Claims] 1. An eddy current displacement sensor provided in a barrel of a screw type extruder is used to measure the deflection of a screw rotatably inserted in a barrel hole of the barrel of the screw type extruder. A method for measuring the runout of a screw type extruder in which the distance to the tip surface of the screw blade is measured. 2. The screw according to claim 1, wherein a plurality of eddy current displacement sensors are used for the screw to measure the distances to the tip surfaces of the screw blades having different phases of the screw. Method for measuring the runout of the screw of a rotary extruder. 3. A screw type extruder having a barrel and a screw rotatably inserted into a barrel hole of the barrel, wherein the tip end surface constitutes a part of an inner peripheral surface of the barrel hole. A sensor holder provided on the barrel,
An eddy current displacement sensor that is held by the sensor holder and detects the distance to the screw during operation, and a sensor output that processes the output from the eddy current displacement sensor to measure the distance to the screw blade tip surface. A screw type extruder equipped with a processing means. 4. The screw type extruder according to claim 3, wherein the sensor holder is made of engineering plastic or ceramic. 5. The screw type extruder according to claim 3, further comprising a sensor temperature adjusting means for holding the eddy current type displacement sensor at a substantially constant temperature.