JPH063245A - Method and device for measuring melt index - Google Patents

Abstract

PURPOSE:To improve the instability of operation by a residual material and negative pressure and the damage by an inorganic material, and facilitate the discharge of the residual material and the maintenance and inspection of a measuring device. CONSTITUTION:A cylinder 10 has an orifice 16 on the top end wall part of a piston head side chamber 14 and a communicating hole 36 on the side part. On the outer diameter part of a piston 12, a groove 15 communicating with the piston head side chamber 14 is formed. The groove 15 is opened by the communicating hole 36 in the first rotating position of the piston 12 to the cylinder and closed in the second rotating position by the cylinder wall surface. The outlet port 32 of a resin processing device 30 is connected to the communicating hole 36 through a communicating pipe 34. A piston rod 24 is held in such a manner as to be capable of being pressed by a fixed pressing force reciprocating driving device 22 and rotatable by a rotating device 26a The fixed pressing force reciprocating driving device 22 is controlled in the driving force and the operating timing with the rotating device 26 by a control device 38. The pressing speed of the piston rod 24 is measured by a pressing speed measuring device 28, and on the basis of this value, the control device 38 can calculate MI.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melt index measuring method and apparatus.

[0002]

2. Description of the Related Art Regarding a resin material, a melt index (hereinafter referred to as "MI" in this specification) in a molten state.
And The melt flow index: MIF or the melt flow rate: MFR is also called), that is, the weight flow rate per specified time under specified test conditions is used as the main physical property value. There is a method in which a resin is heated and melted, a molten resin at a specified temperature is extruded from an orifice at a specified pressure, and an extruded weight (flow rate) at a specified time is obtained (JIS K
6900 and K7210). However, in the case of measuring the MI of the molten resin in the operating apparatus or the storage container, according to the measurement method using a regular MI meter, the molten resin must be once solidified into fine particles and then remelted to a specified temperature. First, it takes a time of 10 minutes from the collection to the acquisition of MI. Therefore, the M of the resin whose physical properties have changed in the operating equipment or storage container
It is almost impossible to obtain I immediately and to control the operating conditions of the device by constantly monitoring the change in MI.

As a countermeasure against this, a small amount of molten resin is constantly extracted from an operating apparatus or storage container, and a pseudo M
I is measuring. That is, as shown in FIG.
A gear pump 102 for extracting molten resin from the resin processing apparatus 100 is connected to the resin processing apparatus 100.
An orifice 104 that pushes the molten resin that is to be sent into the atmosphere is connected to the. The measuring method is to control the rotation of the gear pump 102 so that the pressure gauge 1
The molten resin pressure in front of the orifice 104 measured at 06 is held at a specified value. The resin extruded from the orifice 104 is weighed and the outflow rate is measured.
In this case, the molten resin has tackiness and is continuously extruded in the form of a string, so the outflow rate of the molten resin cannot be directly and automatically measured. Therefore, in order to automatically measure the outflow rate, the outflow rate is obtained from the volume outflow rate obtained from the rotation speed of the gear pump 102 and the unit volume weight of the molten resin. The molten resin after the measurement is received in a waste container (not shown) or the like.

[0004]

However, the above-mentioned conventional MI measuring method and apparatus have the following problems. In recent years, resin materials have been diversified and the types thereof have become extremely large. This is because the number of types of organic resin materials is increasing and the number of cases in which resin materials in which various inorganic materials are mixed with organic resin materials are produced are increasing. Further, regarding the resin processing apparatus, there are many cases in which the type of resin material is frequently changed to be operated, that is, the resin processing apparatus is used for various kinds of small amount processing. In the case where the MI is constantly measured in such a resin processing apparatus, it is required that the measuring apparatus also has a strength measure against the mixed inorganic material and a prompt measure against the resin material change. Therefore, the measuring device using the gear pump 102, which is a precision assembled product as shown in FIG. 3, has the following problems. That is, in the case of a resin material mixed with an inorganic material, the tooth surface is damaged by the inorganic material caught between the tooth surfaces. Further, a lump of the inorganic material bites between the tooth surfaces, which may prevent stable normal rotation. In addition, it is not possible to easily remove the resin material before the change that has accumulated on the tooth bottom when changing the resin material. Due to these problems, the operating state of the gear pump 102 becomes unstable, and accurate measurement cannot be performed. This will result in unreliable measurement results. Further, since the gear pump 102 is a precision machine, maintenance such as overhaul and inspection is difficult. The present invention aims to solve the above problems.

[0005]

The present invention solves the above problems by measuring the MI of the liquid to be measured by a cylinder. That is, in the MI measuring method of the present invention, the piston fitted in the cylinder is moved in one direction at the first rotation position of the piston, so that the first communication port of the cylinder and the first communication port of the cylinder are provided in a predetermined chamber defined by the cylinder and the piston. By sucking the liquid to be measured through the groove on the outer circumference of the piston, then rotating the piston from the first rotation position to the second rotation position with respect to the cylinder and moving the piston in the other direction with a constant force, The liquid to be measured is discharged to the outside from the orifice portion provided in the, and MI is calculated based on the moving speed of the piston rod at this time. Further, by moving the piston fitted in the cylinder in one direction at the first rotation position thereof, the first chamber of the cylinder is placed in a predetermined chamber defined by the cylinder and the piston.
To suck the liquid to be measured through the communication port and the groove on the outer circumference of the piston, then rotate the piston from the first rotation position to the second rotation position with respect to the cylinder, and move the piston in the other direction at a constant speed. Thus, the liquid to be measured can be discharged to the outside from the orifice portion provided in the cylinder, and MI can be calculated based on the moving speed of the piston rod at this time.

Further, the MI measuring device of the present invention comprises a reciprocating driving device (2) connected to a cylinder (10) and a piston rod (24) of a piston (12) fitted to the cylinder (10).
2), a speed measuring device (28) for measuring the moving speed of the piston rod (24), and a rotating device (26) capable of rotating the piston (12) between a first rotation position and a second rotation position.
And a control device (38), and a groove (15) communicating with a chamber (14) defined by the piston is axially formed in the piston (12) in the axial direction. The cylinder (10) is provided with a communication port (36) capable of opening the groove (15) at the first rotation position of the piston and penetrates the wall portion of the chamber (14). And an orifice (16) is formed,
The communication port (36) is capable of communicating with the suction source of the liquid to be measured, and the reciprocating drive device (22) is capable of axially driving the piston rod (24) with a constant force. 38) can set the driving force of the reciprocating drive device (22) and can control the rotating device (26) and the reciprocating drive device (22) to operate in a predetermined operation sequence. The MI of the liquid to be measured is calculated based on the moving speed value of the piston rod (24) measured by the speed measuring device (28).
The cylinder (10), the constant speed reciprocating drive device (40) connected to the piston rod (24) of the piston (12) fitted to the cylinder (10), and the piston (12)
A rotation device (2 that is rotatable between a rotation position and a second rotation position).
6) and the pressure measuring device (4) provided in the chamber (14) of the cylinder (10) partitioned by the piston (12).
2) and a control device (44), and the piston (12) has an axially formed groove (15) communicating with the chamber (14) in the outer diameter portion thereof. The cylinder (10) has a communication port (36) capable of opening the groove (15) at the first rotation position of the piston (12).
Is provided and an orifice (16) is formed through the wall of the chamber (14), and the communication port (36) can communicate with the suction source of the liquid to be measured. The reciprocating drive device (40) can drive the piston rod (24) in the axial direction at a constant speed, and the control device (44) can set the drive speed of the constant speed reciprocating drive device (40). And the rotating device (2
6) and the constant speed reciprocating drive device (40) can be controlled so as to operate in a predetermined operation sequence, and based on the pressure value of the chamber (14) measured by the pressure measuring device (42). The MI of the measurement liquid may be calculated. Further, the cylinder (10) may be provided with a temperature controllable heating device. The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0007]

With the communication port of the cylinder communicating with the suction source of the liquid to be measured, when the piston is first withdrawn from the cylinder at the first rotation position of the piston, the volume of the cylinder chamber increases and the internal pressure becomes negative. Falls to pressure. Since the device or storage container in operation which is the suction source of the liquid to be measured is usually in a high pressure state, the liquid to be measured is sucked into the chamber from the suction source of the liquid to be measured. At this time, the communication pipe that connects the suction source of the liquid to be measured and the chamber has a small flow resistance and the flow resistance of the orifice is large. The suction phenomenon at the orifice hardly occurs since it is sucked in quickly and quickly. After the piston is completely pulled out, the suction source of the liquid to be measured and the chamber are kept in communication for a while, so that the liquid to be measured is pushed from the suction source of the liquid to be measured into the chamber, Can be completely filled with the liquid to be measured. Next, when the piston is pushed into the cylinder at the second rotation position where the piston is rotated relative to the cylinder by a predetermined angle, the volume of the chamber is reduced and the internal pressure is increased. Therefore, the liquid to be measured is discharged from the chamber to the outside via the orifice. As described above, by repeating the reciprocating movement of the piston rod, the liquid to be measured sequentially flows from the suction source of the liquid to be measured to the chamber, the orifice, and the outside. For the liquid to be measured that passes through the orifice, MI is determined based on JIS K7210. Further, by setting the measurement condition arbitrarily, the pseudo MI, that is, the outflow rate under the measurement condition different from the JIS specified condition is obtained. Further, by continuously measuring the outflow velocity or the volume flow rate under the condition that the measurement condition is an arbitrary constant value, the measurement result, that is, the pseudo M
A change in MI can be inferred from a change in I. When the piston is driven, the MI or pseudo MI of the liquid to be measured can be obtained by driving the piston with a constant force and simultaneously measuring the moving speed. That is, the pseudo MI is obtained by obtaining the ejection pressure of the liquid to be measured from the driving force and the acting area of the piston, and the volume flow rate of the liquid to be measured from the moving speed and the acting area of the piston. At this time, if the discharge pressure is a JIS standard pressure, the MI is obtained by the unit volume weight of the measured liquid that is obtained in advance, or by measuring the unit volume weight of the discharged measured liquid. . In this case, since only the moving speed is a variable, MI or pseudo MI can be uniquely obtained by measuring the moving speed of the piston. Further, when the piston is driven, the MI or pseudo MI of the liquid to be measured is obtained by driving the piston at a constant moving speed and simultaneously measuring the pressure of the liquid to be measured in the chamber. That is, the discharge pressure of the measured liquid is calculated from the measured liquid pressure of the chamber, and the volumetric flow rate of the measured liquid is calculated from the moving speed and the working area of the piston.
Alternatively, pseudo MI is required. In this case, since only the measured liquid pressure in the chamber is a variable, MI or pseudo MI
Can be uniquely obtained by measuring the measured liquid pressure in the chamber.

In the structure of the apparatus, the cylinder sucks the liquid to be measured into the chamber when the piston is pulled out, and expels the liquid to be measured from the chamber when the piston is pushed. The orifice causes flow resistance in the liquid to be measured flowing from the chamber to the discharge destination. The communication pipe serves as a flow path for allowing the liquid to be measured to flow by communicating between the suction source of the liquid to be measured and the chamber.
The reciprocating drive device drives the piston rod in the axial direction of the cylinder with a preset constant force. The speed measuring device measures the relative speed of the piston rod with respect to the cylinder when the piston rod is driven. The rotating device rotates the piston rod to relatively rotate the piston with respect to the cylinder between the first rotation position and the second rotation position, and communicates between the piston head side chamber and the suction source of the liquid to be measured. And the state of shutting off. The control device controls the driving force of the piston rod to be constant by presetting the driving force of the reciprocating driving device. Also,
The control device switches between the first rotation position and the second rotation position of the piston by the rotation device so as to pull out the piston rod in the state of the first rotation position of the piston and push the piston rod in the state of the second rotation position. , And the operation of pushing and pulling the piston rod by the reciprocating drive device in association with each other to control them. Further, the control device can calculate MI or pseudo MI from a moving speed value or a set value of the piston rod measured by the speed measuring device according to a preset calculation formula. The constant speed reciprocating drive device drives the piston rod in the axial direction at a preset constant speed. The pressure measuring device measures the pressure of the measured liquid in the piston head side chamber when the measured liquid passes through the orifice. The control device having the constant speed reciprocating drive device and the pressure measuring device as constituent elements controls the moving speed of the piston rod by presetting the moving speed of the constant speed reciprocating drive device.
In addition, the control device pulls out the piston rod in the state of the first rotation position of the piston and pushes the piston rod in the state of the second rotation position so that the rotation device moves between the first rotation position and the second rotation position of the piston. The switching and the operations of pushing and pulling out the piston rod by the constant speed reciprocating drive device are associated with each other to control them. Further, the control device calculates MI or pseudo MI from a measured liquid pressure value or set value measured by the pressure measuring device, according to a preset calculation formula. The heating device is
The measuring device is heated to an arbitrary set temperature including the specified temperature, and the liquid to be measured is kept in a constant measured temperature state. As a result, a predetermined temperature state can be secured for the liquid to be measured having a high temperature exceeding 100 ° C. without being affected by changes in the surroundings.
Since stable measurement is performed, highly reliable measurement results can be obtained.

[0009]

FIG. 1 shows the first embodiment of the present invention. A cylinder 10 capable of flowing a molten resin (liquid to be measured) has a piston head side chamber 14 (chamber) formed in front of a piston 12 fitted therein. A groove 15, which will be described later, is formed in the outer diameter portion of the piston 12 so as to communicate with the piston head side chamber 14 in the axial direction. An orifice 16 is formed penetrating the tip wall of the piston head side chamber 14. In FIG. 1, a discharge container 18 for receiving the discharged molten resin is provided below the orifice 16. A constant pushing force reciprocating drive device 22 (reciprocating drive device) is attached to the cylinder 10 by a connecting member 20. The constant pushing force reciprocating drive device 22 holds a piston rod 24 projecting from the cylinder 10 so as to be axially drivable,
Piston rod 2 to generate the flow force of molten resin
4 can be pushed in with a constant force. In the vicinity of the piston rod 24 holding portion of the constant pushing force reciprocating drive device 22, the rotating device 2
6 is attached. The rotation device 26 can rotate the piston rod 24 relative to the cylinder between the first rotation position and the second rotation position. Constant pushing force reciprocating drive device 22
A pushing speed measuring device 28 (speed measuring device) is also attached near the holding portion of the piston rod 24. The pushing speed measuring device 28 is a device that measures a linear velocity, and can measure the pushing speed of the piston rod 24. The resin processing device 30 (source of suction of the liquid to be measured) is connected at its outlet 32 via a communication pipe 34 to a communication port 36 described later, which can communicate with the piston head side chamber 14. The constant pushing force reciprocating drive device 22, the rotating device 26, and the pushing speed measuring device 28 are
It is connected to a control device 38 capable of controlling the operation of all of these. The control device 38 has a setting unit, a detection unit, a calculation unit, a drive unit, and an output unit, which are not shown, and is capable of exchanging a control signal and a data signal with each of the above-mentioned devices, and also MI Alternatively, the pseudo MI calculation can be performed.

FIG. 2 is a sectional view taken along line 2-2 of FIG. In the first rotation position of the piston 12, the groove 15 of the piston 12 is opened by the communication port 36. At the second rotational position where the piston 12 rotates relative to the cylinder in the counterclockwise direction by the rotational angle θ from the first rotational position, the groove 15 of the piston 12 is closed by the wall surface of the cylinder.

Next, the operation of this embodiment will be described.
In the control device 38, the pushing force of the piston rod 24 is set to a predetermined value in advance. Thereby, the driving force of the constant pushing force reciprocating drive device 22 can be controlled to a predetermined magnitude. In the case where the piston 12 is in the second rotation position and the piston rod 24 is in the most pushed-in position and there is no molten resin in the piston head side chamber 14, first, the piston rod 24 is rotated by the rotation device 26. Then, the piston 12 is brought into the state of the first rotation position. As a result, the outlet 32 of the resin processing device 30 communicates with the piston head side chamber 14 via the communication pipe 34, the communication port 36 and the groove 15. Next, the piston rod 24 is pulled out from the cylinder by the constant pushing force reciprocating drive device 22. As a result, the molten resin is sucked into the piston head side chamber 14 from the outlet 32 of the resin processing device 30. The constant pushing force reciprocating drive device 22 stops when the piston rod 24 is pulled out most. As a result, new molten resin is sucked into the piston head side chamber 14 from the resin processing device 30 until it is filled. Next, the rotation device 26
Causes the piston rod 24 to rotate in the counterclockwise direction by the rotation angle θ to bring the piston 12 into the state of the second rotation position shown in FIG. As a result, the groove 15 and the communication port 36 are shut off from each other. Next, the constant pushing force reciprocating drive device 22 pushes the piston rod 24 into the cylinder with a predetermined pushing force and activates the pushing speed measuring device 28. As a result, the molten resin in the piston head side chamber 14 is discharged to the outside via the orifice 16 and stored in the discharge container 18. At this time, the molten resin undergoes a flow resistance proportional to the viscosity when passing through the orifice 16. Therefore, the piston rod 24 is pushed in at a speed inversely proportional to the viscosity. The pushing speed of the piston rod 24 is measured by the pushing speed measuring device 28 and transmitted to the control device 38. In the control device 38, the MI based on this measurement data
Alternatively, the pseudo MI is calculated. That is, the volumetric flow rate q of the molten resin is obtained from the pushing speed of the piston rod 24 and the surface area of the piston 12 on the piston head side chamber 14 side, and MI or pseudo MI is obtained from this q and the unit volume weight of the molten resin. When the piston rod 24 is pushed in the most, the constant pushing force reciprocating drive device 22 stops.
At this time, all the molten resin in the piston head side chamber 14 is discharged. After that, the rotation device 26 rotates the piston rod 24 in the clockwise direction by the rotation angle θ to bring the piston 12 into the state of the first rotation position, and the subsequent operations described above are sequentially repeated.

FIG. 3 shows a second embodiment. This is a constant pushing speed reciprocating driving device 4 capable of pushing the piston rod 24 at a constant driving speed instead of the constant pushing force reciprocating driving device 22 and the pushing speed measuring device 28 of the first embodiment shown in FIG.
0 (constant speed reciprocating drive device) is provided, a pressure measuring device 42 for measuring the pressure of the molten resin is provided in the piston head side chamber 14, and instead of the control device 38, a constant pushing speed reciprocating drive device 40, a rotating device 26 and a pressure. A control device 44 capable of communicating a control signal and a data signal with the measuring device 42 is provided, and the other constituent elements are the same as those in the first embodiment.

Next, the operation of the second embodiment will be described. Piston rod 24 of constant pushing speed reciprocating drive device 40
Of the molten resin in the piston head side chamber 14 when the molten resin is pushed out of the orifice 16 by the pressure measuring device 42, and the measured data is transmitted to the control device 44. What to do,
Except for the above, the basic operation is the same as that of the first embodiment.
The control device 44 calculates MI or pseudo MI.
That is, q is obtained from the preset driving speed of the piston rod and the surface area of the piston 12 on the piston head side chamber 14 side, and MI or pseudo MI is obtained from this q and the unit volume weight of the molten resin.

If a heating device capable of controlling the temperature is provided for each of the cylinder 10 and the communication pipe 34, the temperature of the molten resin can be stably maintained at a predetermined temperature. Also,
In the above embodiment, the orifice 16 is formed so as to penetrate the tip wall portion of the piston head side chamber 14, but the invention is not limited to this, and it may be formed so as to penetrate the side cylinder wall portion. Although the molten resin is described in the above embodiment,
The present invention is not limited to this, and can be applied to MI measurement of other liquids.

[0015]

According to the present invention, in order to measure MI or pseudo MI by sucking the liquid to be measured into the cylinder from the suction source of the liquid to be measured and discharging it from the orifice, the piston rod of the cylinder is axially moved. By driving the liquid to be measured, a fluid force is applied to the liquid to be measured. Since the cylinder has a simple structure, the influence of inorganic materials on the instability of the operation and the instability of the operation due to the residual material is greatly improved, and the residual material can be discharged easily and quickly even when the material is changed, and it can be disassembled and assembled. Since it is easy to perform, maintenance and inspection of the measuring device has become easier. Further, since the flow path is blocked and the measurement operation is completely separated from the suction operation and the measurement operation,
Compared to the conventional state in which the measuring part is made to flow while receiving the pressure of the supplied material, more accurate measurement is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 10 Cylinder 12 Piston 14 Piston Head Side Chamber (Room) 15 Groove 16 Orifice 22 Constant Pushing Force Reciprocating Drive Device (Reciprocating Drive Device) 24 Piston Rod 26 Rotating Device 28 Pushing Speed Measuring Device (Speed Measuring Device) 30 Resin Processing Device (Measured) Liquid suction source) 36 Communication ports 38, 44 Control device 40 Constant pushing speed reciprocating drive device (constant speed reciprocating drive device) 42 Pressure measuring device

Claims (5)

[Claims] 1. A piston fitted in a cylinder is moved in one direction at a first rotation position of the piston, so that a first communication port of the cylinder and a groove on the outer circumference of the piston are provided in a predetermined chamber defined by the cylinder and the piston. The liquid to be measured is sucked in through the piston, and then the piston is moved from the first rotation position to the second rotation position.
By rotating the piston to the rotating position and moving the piston in the other direction with a constant force, the liquid to be measured is discharged to the outside from the orifice provided in the cylinder, and the moving speed of the piston rod at this time is used as the basis. Melt index measuring method to calculate melt index. 2. A piston fitted in a cylinder is moved in one direction at a first rotation position of the piston, whereby a first communication port of the cylinder and a groove on the outer circumference of the piston are provided in a predetermined chamber defined by the cylinder and the piston. The liquid to be measured is sucked in through the piston, and then the piston is moved from the first rotation position to the second rotation position.
By rotating the cylinder to the rotation position and moving the piston in the other direction at a constant speed, the liquid to be measured is discharged to the outside from the orifice provided in the cylinder,
A melt index measuring method for calculating the melt index based on the moving speed of the piston rod at this time. 3. A cylinder (10), a reciprocating drive (22) connected to a piston rod (24) of a piston (12) fitted therein, and a piston rod (2).
4) a speed measuring device (28) for measuring the moving speed, a rotating device (26) capable of rotating the piston (12) between a first rotation position and a second rotation position, and a control device (38). The piston (12) has an axially formed groove (15) communicating with a chamber (14) defined by the piston on the outer diameter of the piston (12), and the groove (15) is formed in the cylinder (10). Is provided with a communication port (36) capable of opening the groove (15) at the first rotation position of the piston, and an orifice (16) is formed through the wall of the chamber (14). The communication port (36) can communicate with the suction source of the liquid to be measured, and the reciprocating drive device (22) can drive the piston rod (24) in the axial direction with a constant force to perform the control. The device (38) is the reciprocating drive device (2
The driving force of 2) can be set, and the rotating device (26) and the reciprocating driving device (22) can be controlled so as to operate in a predetermined operation sequence, and are measured by the speed measuring device (28). Above piston rod (2
A melt index measuring device for calculating the melt index of the liquid to be measured based on the moving speed value of 4). 4. A cylinder (10), a constant speed reciprocating drive (40) connected to a piston rod (24) of a piston (12) fitted thereto, and a piston (1).
2) a rotation device (26) capable of rotating between a first rotation position and a second rotation position, and a pressure measurement device (42) provided in a chamber (14) of a cylinder (10) partitioned by a piston (12). ) And a control device (44), and the piston (12) has an outer diameter portion thereof with the chamber (1).
The groove (15) communicating with 4) is formed in the axial direction,
The cylinder (10) is provided with a communication port (36) capable of opening the groove (15) at the first rotation position of the piston (12) and penetrates the wall portion of the chamber (14). An orifice (16) is formed, the communication port (36) can communicate with the suction source of the liquid to be measured, and the constant speed reciprocating drive device (40) moves the piston rod (24) at a constant speed. Can be driven axially with
The control device (44) includes the constant speed reciprocating drive device (4).
0) the drive speed can be set, and the rotating device (26) and the constant speed reciprocating drive device (40) can be controlled so as to operate in a predetermined operation sequence, and by the pressure measuring device (42). A melt index measuring device for calculating a melt index of a liquid to be measured based on the measured pressure value of the chamber (14). 5. The melt index measuring device according to claim 3, wherein the cylinder (10) is provided with a temperature controllable heating device.