JPH063244A - Method and device for measuring melt index - Google Patents

Abstract

PURPOSE:To improve the instability of operation by a residual material and a 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 a piston head side chamber 18 formed in the front of a piston 12. The piston head side chamber 18 has an orifice 20 formed extending through the top end wall part, and is allowed to communicate with a resin processing device 32 through communicating pipes 28, 26. Each communicating pipe 28, 36 is connected to a selector 30 capable of opening the pipe in a first position 38 and closing it in a second position 40, respectively. A piston rod 14 is held by 8 fixed pressing force reciprocating driving device 24 in such a manner as to be capable of being pressed. The fixed pressing force reciprocating driving device 24 is controlled in the driving force and the operating timing with the selector 30 by control device 42. The driving speed of the piston rod 14 is measured by a pressing speed measuring device 26, and on the basis of this value, MI can be calculated by the control device 42.

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 supplying and discharging the liquid to be measured to and from the orifice by means of a cylinder and a piston. That is, in the melt index measuring method of the present invention, the piston fitted in the cylinder is moved in one direction so that the liquid to be measured is sucked into a predetermined chamber defined by the cylinder and the piston, and then the piston is moved in the other direction. The liquid to be measured is discharged from the orifice portion provided in the cylinder to the outside by moving the piston rod at a constant force, 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, the liquid to be measured is sucked into a predetermined chamber defined by the cylinder and the piston, and then the piston is moved in the other direction at a constant speed. , The liquid to be measured is discharged to the outside from the orifice portion provided in the cylinder, and M is determined based on the moving speed of the piston rod at this time.
It is also possible to calculate I.

Further, the MI measuring device of the present invention comprises a reciprocating drive device (2) connected to a cylinder (10) and a piston rod (14) of a piston (12) fitted to the cylinder (10).
4), a speed measuring device (26) for measuring the moving speed of the piston rod (14), and two ports (31, 37)
A communication valve (28) and a control device (42), and the cylinder (10) has a chamber (1) partitioned by the piston (12).
An orifice (20) is formed through the wall of 8), and the switching valve (30) has a first port (31) connected to the chamber (18) through a communication pipe (28). And the second port (37) is the source of the liquid to be measured (32)
Is in communication with the first position (38).
The port (31) and the second port (37) are communicated with each other, and the first position (31) and the second port (37) can be switched off at the second position (40).
The reciprocating drive device (24) includes the piston rod (1
4) can be driven in the axial direction with a constant force, and the control device (42) can set the driving force of the reciprocating drive device (24), and the switching valve (30) and the reciprocating drive device (42). 24) can be controlled to operate in a predetermined operation sequence, and MI of the liquid to be measured is calculated based on the moving speed value of the piston rod (14) measured by the speed measuring device (26). Is. Also, the cylinder (10) and the piston (12) fitted to the cylinder (10).
Constant speed reciprocating drive device (44) connected to the piston rod (14), a switching valve (30) having two ports (31, 37), a communication pipe (28), and a cylinder (1).
0) has a pressure measuring device (46) provided in the piston head side chamber (18) and a control device (48), and the cylinder (10) has the piston (12).
An orifice (20) is formed through the wall of the chamber (18) partitioned by the switching valve (30).
Has a first port (31) connected to the chamber (18) through a communication pipe (28), and a second port (37) can communicate with a suction source (32) of the liquid to be measured. The first port (31) and the second port (37) communicate with each other at the first position (38), and the first port (31) and the second port (37) cut off at the second position (40). The constant speed reciprocating drive device (4
4) is capable of axially driving the piston rod (14) at a constant speed, and the control device (48) is capable of setting the drive speed of the constant speed reciprocating drive device (44) and switching The valve (30) and the constant speed reciprocating drive device (44) are controllable to operate in a predetermined operation sequence, and based on the pressure value of the chamber (18) measured by the pressure measuring device (46). It is also possible to calculate the MI of the liquid to be measured. Further, the cylinder (10), the switching valve (30) and each communication pipe (28) may be provided with a temperature controllable heating device. In addition,
Reference numerals in parentheses indicate corresponding members of the embodiment.

[0007]

When the piston is pulled out of the cylinder at the first position of the switching valve with the second port of the switching valve communicating with the suction source of the liquid to be measured, the volume of the cylinder chamber increases and the internal pressure increases. Decreases to negative pressure. Since the device or storage container in operation which is the suction source of the liquid to be measured is normally in a high pressure state, the liquid to be measured is sucked and flows from the suction source of the liquid to be measured into the chamber. At this time, each communication pipe has a small flow resistance, and the orifice has a large flow resistance. Also, since the liquid to be measured flows in easily and quickly due to the high pressure of the suction source of the liquid to be measured, the suction phenomenon at the orifice is almost eliminated. It won't happen. Further, after the piston is completely pulled out, the chamber can be completely filled with the liquid to be measured by keeping the suction source of the liquid to be measured and the chamber in communication with each other for a while. Next, when the piston is pushed in at the second position of the switching valve, the volume of the chamber decreases and the internal pressure rises. Therefore, the liquid to be measured is discharged from the chamber via the orifice and flows out to the outside. As described above, by repeating the reciprocating motion of the piston, the liquid to be measured sequentially flows from the suction source of the liquid to be measured to the piston head side 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 volumetric flow rate with the measurement condition set to an arbitrary constant value, the change in MI can be estimated from the measurement result, that is, the change in pseudo MI. When the piston is driven, the MI of the liquid to be measured is measured by driving the piston with a constant force and simultaneously measuring the moving speed.
Alternatively, the pseudo MI can be obtained. That is, the discharge pressure of the liquid to be measured is obtained from the driving force and the acting area of the piston, and the volumetric flow rate of the liquid to be measured is obtained from the moving speed and the acting area of the piston.
Is required. 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. Further, when the piston is driven, the MI or pseudo MI of the liquid to be measured is obtained by measuring the liquid pressure to be measured in the piston head side chamber while driving the piston at a constant moving speed. That is, the discharge pressure of the measured liquid from the measured liquid pressure of the chamber, the volume flow rate of the measured liquid from the moving speed and the working area of the piston,
Each is obtained, and MI or pseudo MI is obtained. 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 configuration of the apparatus, the cylinder sucks the liquid to be measured into the chamber when the piston is pulled out, and discharges 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 switching valve switches between the first position and the second position to switch between the communication state and the cutoff state between the suction source of the liquid to be measured and the chamber. Each 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, and a switching valve is interposed in the middle thereof. 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 control device controls the pushing force of the piston rod by presetting the driving force of the reciprocating drive device, pulls out the piston rod in the state of the first position of the switching valve, and pushes it in the state of the second position. The reciprocating drive device and the switching valve are controlled by associating the switching of the valve with the driving of the piston rod, and the MI value is calculated from a moving speed value or set value of the piston rod measured by the speed measuring device according to a preset formula. Alternatively, the pseudo MI is calculated. Further, 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 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 drive speed of the constant speed reciprocating drive device, and the first position of the switching valve. In order to pull out the piston rod in the state of 2 and push in the piston rod in the state of 2nd position, the constant speed reciprocating drive device and the switching valve are controlled by associating the switching of the switching valve with the driving of the piston rod, and the pressure measuring device is used. From the measured measured liquid pressure value or set value, MI or pseudo MI is calculated by a preset calculation formula. The heating device heats the measuring device to an arbitrary set temperature including a specified temperature, and holds the liquid to be measured in a constant measured temperature state. As a result, for a liquid to be measured at a high temperature exceeding 100 ° C
Since a predetermined temperature state is secured and stable measurement is performed without being affected by changes in the surroundings, highly reliable measurement results can be obtained.

[0009]

FIG. 1 shows the first embodiment of the present invention. A piston head side chamber 18 (chamber) is formed in front of a piston 12 fitted to the cylinder 10 in which a molten resin (liquid to be measured) can flow. Piston head side chamber 1
An orifice 20 is formed so as to penetrate the tip wall portion of No. 8. In FIG. 1, a discharge container 21 for receiving the discharged molten resin is provided below the orifice 20.
A constant pushing force reciprocating drive device 24 (reciprocating drive device) is attached to the cylinder 10 by a connecting member 22.
The constant pushing force reciprocating drive device 24 holds the piston rod 14 projecting from the cylinder 10 so as to be axially drivable, and can push the piston rod 14 with a constant force in order to generate a flow force of the molten resin. . A pushing speed measuring device 26 (speed measuring device) is attached near the piston rod 14 holding portion of the constant pushing force reciprocating drive device 24. The pushing speed measuring device 26 is a device that measures a linear speed, and can measure the pushing speed of the piston rod 14. The piston head side chamber 18 of the cylinder 10 is connected to the first port 31 of the switching valve 30 via the first communication pipe 28 (communication pipe). The switching valve 30 is a two-position switching valve having two ports, and can switch between communication and cutoff of the flow path of the molten resin. In the resin treatment device 32 (source of suction of the liquid to be measured), the outlet 34 of the liquid treatment device 32 has a second communication pipe 36
Is connected to the second port 37 of the switching valve 30 via. Constant pushing force reciprocating drive device 24, pushing speed measuring device 26
The switching valve 30 and the switching valve 30 are connected to a control device 42 capable of controlling the overall operation thereof. The control device 42 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 control signals and data signals with the above-mentioned devices, as well as MI. Alternatively, the pseudo MI calculation can be performed.

Next, the operation of this embodiment will be described.
The drive force of the piston rod 14 is preset to a predetermined value in the control device 42. As a result, the driving force of the constant pushing force reciprocating drive device 24 can be controlled to a predetermined magnitude. In the case where the piston rod 14 of the cylinder 10 is at the most pushed position and there is no molten resin in the piston head side chamber 18, first, the switching valve 30 is switched to the first position 38. Thereby, the resin processing device 32
Outlet 34 communicates with the piston head side chamber 18 via the second communication pipe 36 and the first communication pipe 28. Next, the piston rod 14 is pulled out from the cylinder by the constant pushing force reciprocating drive device 24. As a result, the molten resin flows from the outlet 34 of the resin processing device 32 into the piston head side chamber 18. The constant pushing force reciprocating drive device 24 is a piston rod 14.
Stop when you pull out the most. As a result, new molten resin is sucked into the piston head side chamber 18 from the resin processing device 32 until it is filled. Next, the switching valve 30 is switched to the second position 40. As a result, the second communication pipe 36 and the first communication pipe 28 are cut off, and the communication state between the outlet 34 and the piston head side chamber 18 is cut off. Next, the piston rod 1 is driven by the constant pushing force reciprocating drive device 24.
4 is pushed into the cylinder with a predetermined pushing force, and the pushing speed measuring device 26 is operated. As a result, the molten resin in the piston head side chamber 18 is discharged to the outside via the orifice 20 and is stored in the discharge container 21. At this time, the molten resin undergoes a flow resistance proportional to the viscosity when passing through the orifice 20. Therefore, the piston rod 14 is pushed in at a speed inversely proportional to the viscosity. The pushing speed of the piston rod 14 is the pushing speed measuring device 26.
Is measured and transmitted to the control device 42. In the control device 42, MI or pseudo M is calculated based on this measurement data.
I is calculated. That is, the volumetric flow rate q of the molten resin is obtained from the pushing speed of the piston rod 14 and the surface area of the piston 12 on the piston head side chamber 18, and MI or pseudo MI is obtained from this q and the unit volume weight of the molten resin. When the piston rod 14 is pushed in the most, the constant pushing force reciprocating drive device 24 stops. At this time, all the molten resin in the piston head side chamber 18 is discharged. After this, the switching valve 30 is switched to the first position 38,
The subsequent operations described above are sequentially repeated.

FIG. 2 shows a second embodiment. This is a constant pushing speed reciprocating driving device 4 capable of pushing the piston rod 14 at a constant pushing speed, instead of the constant pushing force reciprocating driving device 24 and the pushing speed measuring device 26 of the first embodiment shown in FIG.
4 (constant speed reciprocating drive device), a pressure measuring device 46 for measuring the pressure of the molten resin in the piston head side chamber 18, and a constant pushing speed reciprocating driving device 44 and a pressure measuring device 46 instead of the control device 42. A control device 48 capable of communicating control signals and data signals between them is provided, and the other constituent elements are the same as in the first embodiment.

Next, the operation of the second embodiment will be described. Piston rod 14 of constant pushing speed reciprocating drive device 44
Of the molten resin in the piston head side chamber 18 when the molten resin is discharged from the orifice 20 by the pressure measuring device 46, and the measured data is transmitted to the control device 48. What to do,
Except for the above, the basic operation is the same as that of the first embodiment.
The control device 48 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 18 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 in each of the cylinder 10, the switching valve 30, and the communication pipes 28 and 36, the temperature of the molten resin can be stably maintained at a predetermined temperature. Further, in the above embodiment, the orifice 20 is formed so as to penetrate the tip end wall portion of the piston head side chamber 18, but the invention is not limited to this, and it may be formed so as to penetrate the side cylinder wall portion. Further, although the molten resin is described in the above-mentioned embodiment, the present invention is not limited to this, and can be applied to MI measurement of other liquids.

[0014]

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, 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.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

 10 Cylinder 12 Piston 14 Piston Rod 18 Piston Head Side Chamber (Room) 20 Orifice 24 Constant Push Force Reciprocating Drive Device (Reciprocating Drive Device) 26 Pushing Speed Measuring Device (Speed Measuring Device) 28 First Communication Pipe (Communication Pipe) 30 Switching Valve 38 1st position 40 2nd position 42, 48 control device 44 constant pushing speed reciprocating drive device (constant speed reciprocating drive device) 46 pressure measuring device

Claims (5)

[Claims] 1. A piston fitted in a cylinder is moved in one direction to suck a liquid to be measured into a predetermined chamber defined by the cylinder and the piston, and then the piston is moved in the other direction with a constant force. By doing so, the liquid to be measured is discharged to the outside from the orifice portion provided in the cylinder, and the melt index is calculated based on the moving speed of the piston rod at this time. 2. A piston fitted in a cylinder is moved in one direction to suck a liquid to be measured into a predetermined chamber defined by the cylinder and the piston, and then the piston is moved in the other direction at a constant speed. By letting
A melt index measuring method in which a liquid to be measured is discharged to the outside from an orifice portion provided in a cylinder, and a melt index is calculated based on a moving speed of a piston rod at this time. 3. A cylinder (10), a reciprocating drive (24) connected to the piston rod (14) of a piston (12) fitted therein, and a piston rod (1).
4) a speed measuring device (26) for measuring the moving speed and 2
A switching valve (30) having two ports (31, 37);
The cylinder (10) has a communication pipe (28) and a control device (42), and an orifice (passes through the wall of the chamber (18) defined by the piston (12) in the cylinder (10). 20) is formed, and in the switching valve (30), the first port (31) is connected to the chamber (1) through the communication pipe (28).
8), the second port (37) can communicate with the suction source (32) of the measured liquid, and the first position (3)
8) Switching between connecting the first port (31) and the second port (37) at the second position (40) and disconnecting the first port (31) and the second port (37) at the second position (40) Yes, the reciprocating drive (24) is
The piston rod (14) can be driven in the axial direction with a constant force, the control device (42) can set the driving force of the reciprocating drive device (24), and the switching valve (30) and the The reciprocating drive device (24) can be controlled to operate in a predetermined operation sequence, and the melt index of the liquid to be measured is based on the moving speed value of the piston rod (14) measured by the speed measuring device (26). Melt index measuring device for calculating. 4. A cylinder (10), a constant speed reciprocating drive (44) connected to a piston rod (14) of a piston (12) fitted therein, and two ports (31, 37). The switching valve (30) and the communication pipe (2
8) and the piston head side chamber (1) of the cylinder (10)
8) has a pressure measuring device (46) and a control device (48), and the cylinder (10) has a wall of a chamber (18) defined by the piston (12). An orifice (20) is formed through the portion, and in the switching valve (30), the first port (31) is connected to the chamber (1) through a communication pipe (28).
8), the second port (37) can communicate with the suction source (32) of the measured liquid, and the first position (3)
8) Switching between connecting the first port (31) and the second port (37) at the second position (40) and disconnecting the first port (31) and the second port (37) at the second position (40) Is possible, and the constant speed reciprocating drive device (4
4) is capable of axially driving the piston rod (14) at a constant speed, and the control device (48) is capable of setting the drive speed of the constant speed reciprocating drive device (44) and switching The valve (30) and the constant speed reciprocating drive device (44) are controllable to operate in a predetermined operation sequence, and based on the pressure value of the chamber (18) measured by the pressure measuring device (46). A melt index measuring device that calculates the melt index of the liquid to be measured. 5. The MI measuring device according to claim 3, wherein the cylinder (10), the switching valve (30) and each communication pipe (28) are provided with a heating device capable of controlling the temperature.