JP2526767B2 - Pressure, volume and temperature characteristic measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring pressure, volume and temperature characteristics of a plastic resin or the like.

[0002]

2. Description of the Related Art In molding of resin such as plastic, shrinkage and deformation due to cooling of the material have a great influence on processing accuracy and product quality. Therefore, the correlation of pressure, volume and temperature of the material is measured in advance. Is essential. As an apparatus for performing such measurement, the sample is housed in a cylinder having a closed container shape, and the heating temperature of the cylinder is gradually changed from the melting region to the solidifying region of the sample while maintaining the pressure of the sample constant, or There is a method in which the pressure is gradually changed while maintaining the temperature constant, the volume of the sample is measured at a plurality of measurement points, and the change in the volume of the sample with respect to the pressure and the temperature is obtained from the measurement result.

When performing the above measurement, in order to reduce the frictional resistance between the inner wall of the cylinder and the sample and prevent air from being mixed into the gap between the samples, a measurement auxiliary material having a melting point sufficiently lower than that of the sample, such as wood. Metal or silicone oil may be mixed with the sample. In this case, since it is impossible to directly measure only the volume of the sample by integrating the sample and the measurement auxiliary material, measure the volume including the measurement auxiliary material and subtract the volume of the measurement auxiliary material from the measurement result. There is a need.
Further, since the device is distorted by the pressure applied to the sample and an error corresponding thereto is added to the volume measurement value, such an error needs to be removed.

Therefore, in the conventional device, as shown in FIG. 6, the volume change with respect to the temperature of the measurement auxiliary material is measured in advance under a predetermined test pressure, and the result is stored as a diagram X,
A diagram Z showing the volume change of the sample is obtained by subtracting the diagram X from the diagram Y when the sample and the measurement auxiliary material are mixed and the change in volume is measured. If the pressure and temperature are the same in the same device, the error of the volume measurement value due to the strain of the device is also equal. Therefore, if the diagram X is subtracted from the diagram Y, the error due to the volume of the measurement auxiliary material and the device strain is removed at once. The true sample volume remains as diagram Z. Although only one line X is shown in FIG. 6, a large number of lines are actually present depending on the test pressure.

[0005]

In the above-mentioned conventional apparatus, the amount of the auxiliary material to be measured when the diagram X is obtained and the diagram Y are used.
If the amount of the measurement auxiliary material is different when the value is calculated, an error occurs depending on the difference. In this case, since the diagram X includes both the volume of the measurement auxiliary material and the error due to strain,
It is not possible to increase or decrease the correction amount obtained in the diagram X in proportion to the change in the mass of the measurement auxiliary material, and in order to ensure the accuracy of the measurement, use the correction diagram X according to the amount of the measurement auxiliary material mixed. It is necessary to ask for each one and store all of them in the device. Therefore, it takes a lot of time and effort to create data, and the amount of data to be stored in the device becomes enormous, which makes the input work troublesome. It is an object of the present invention to provide a pressure, volume and temperature characteristic measuring device that does not require the preparation of a correction diagram separately for each amount of measurement auxiliary material.

[0006]

1 and 5, which show one embodiment, the apparatus of the present invention, in the apparatus of the present invention, the amount of error that the strain of the apparatus gives to the measured value of the volume and the pressure of the sample R Mixing in the sample R and the first correction amount calculation means 15 for obtaining the error amount of the measured value at the pressure and temperature at the time of volume measurement based on the diagram (FIG. 5 (A)) showing the correlation with the temperature and the temperature. Based on the diagram (FIG. 5 (C)) showing the correlation between the pressure of the measurement auxiliary material F, the volume per specific mass, and the temperature, and the mass of the measurement auxiliary material F actually mixed, The second correction amount calculating means 15 for obtaining the true volume of the measurement auxiliary material at the pressure and the temperature, the error amount calculated by the first correction amount calculating means 15, and the second correction amount calculating means 15 are calculated. Volume measurement based on the true volume of the Correct, by providing a sample volume calculation means 15 for determining the true volume of the sample, is aimed to achieve the above object.

[0007]

As shown in FIG. 5 (A), pressure Pt and temperature Tn
Assuming that the volume measurement value at that time is Va, the first correction amount calculation means 15 uses the line showing the correlation between the volume error due to the strain of the device and the pressure and temperature as shown in FIG. 5B. The volume error Vs at the pressure Pt and the temperature Tn is obtained from the figure. On the other hand, the second correction amount calculation means 15 is shown in FIG.
The volume vf per specific mass Ws of the measurement auxiliary material F at the pressure Pt and the temperature Tn is calculated from the diagram showing the correlation of the pressure, volume and temperature of the measurement auxiliary material F as shown in
The ratio Wf / of the actual mass Wf and mass Ws of the measurement auxiliary material
The true volume Vf of the measurement auxiliary material F is obtained by multiplying Ws.
The sample volume calculation means 15 has a volume error V calculated by the first and second correction amount calculation means 15 as shown in FIG.
s and the true volume Vf of the measuring auxiliary material F
The true volume Vr of the sample R is obtained by subtracting from a. The above process is repeated while changing the test pressure and temperature in the same manner, and the true volume Vr of the sample R at each pressure and temperature is repeated.
Ask for.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. It is not limited to.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 show a measuring apparatus according to the present embodiment, in which 1 is an apparatus main body, 2 is a support base supported by the apparatus main body 1, and the support base 2 is rotatable about an axis 2a thereof. To be done. A cylinder 4 is attached to the front part of the support base 2 via a heat insulating material 3, and a center thereof has a sample filling hole 4a filled with a resin sample R to be measured and a wood metal F as a measurement auxiliary material. Is formed.

Reference numeral 5 denotes a pressure head for pressing the sample R. The pressure head 5 is moved vertically by an actuator (not shown), and its tip is a rod inserted into the sample filling hole 4a of the cylinder 4. 6 can be contacted. An elastic body 7 such as urethane and a rigid piston 8 are sequentially arranged below the rod 6. When the pressure head 5 is moved downward, the sample R and the wood metal F filled below the piston 8 are compressed. A pressure corresponding to the displacement of the piston 8 acts on them. The pressure applied to the sample R is the sample filling hole 4a.
It is detected by the pressure sensor 9 provided so as to close the lower end of the. The pressure detected by the pressure sensor 9 is guided to a pressure control device (not shown), and this pressure control device controls the amount of elevation of the pressurizing head 5 based on the pressure command value and the pressure detected by the pressure sensor 9. For example, in the constant pressure test described below,
The lifting amount of the pressure head 5 is increased or decreased so that the pressure detected by the pressure sensor 9 becomes a constant value.

Reference numeral 10 is a temperature sensor for measuring the temperature of the sample R, and 11 is a heater for heating the sample R and the wood metal F. The temperature detected by the temperature sensor 10 is guided to a temperature control device (not shown), and this temperature control device controls the heat generation amount of the heater 11 based on the temperature command value and the actual temperature detected by the temperature sensor 10. For example, in the case of the constant temperature test, the heat generation amount of the heater 11 is controlled so that the temperature detected by the sensor 10 becomes constant. A cooling device (not shown) for cooling the sample R is also attached to the cylinder 4.

The vertical displacement of the piston 8 is transmitted to the displacement detection plate 12 via the rod 8a having a small diameter. The vertical displacement of the displacement detection plate 12 is detected by the laser displacement meter 13 attached to the apparatus body 1, and the detection result is output to the volume calculator 14. The volume calculator 14 calculates the total volume Va of the current sample R and the wood metal F from the diameter of the sample filling hole 4a and the displacement of the piston 8 which are input in advance, and outputs the result to the data processing device 15. To do.

The data processing device 15 is set by the volume setting value Va output from the volume calculator 14, the temperature T detected by the temperature sensor 10, the pressure P detected by the pressure sensor 9, and the condition setter 16. The true volume of the sample R is obtained based on the test conditions described above, and is output to a display device (for example, XY plotter) not shown. Hereinafter, the data processing device 1 will be described with reference to FIG.
The data processing procedure in No. 5 will be described. In addition, the apparatus of the present embodiment has a constant temperature test in which the pressure is changed while maintaining the temperature of the sample R constant and the volume is measured, and the temperature is changed from the melting region to the solidification region while maintaining the pressure of the sample R constant. Any of the constant pressure tests in which the volume is varied by measuring up to a constant value Pt can be performed, but the case where the pressure is maintained at a constant value Pt will be described below as an example. In this case, the test conditions set by the condition setter 16 include the test temperature range Tmin to Tmax, the number of measurements m, and the amount of wood metal F. Maximum value of test temperature range Tma
x is the melting region of the sample R, and the minimum value Tmin is the solidifying region of the sample R and the melting region of the wood metal F.

When the sample R and the wood metal F are filled in the sample filling hole 4a of the cylinder 4 and the test conditions are input to the condition setter 16, heating by the heater 11 is started.
Then, when the sample temperature reaches the first set value of the test temperature, the heating is stopped, the cooling (heating) of the sample R is started, and the processing by the data processing device 15 is started. The data processing device 15 firstly detects the pressure sensor 9 in step S1.
The test pressure Pt of the sample R is read from, and the test temperature range Tmin to Tmax set by the condition setter 16, the number of measurements m, and the amount of wood metal F are read. In the next step S2, the test temperatures T1 to Tm for volume measurement are set for the number of times m of measurement.

After setting the test temperatures T1 to Tm, the variable n indicating the number of times of measurement is reset to zero in step S3, the process proceeds to step S4, and 1 is added to the current variable n. In the next step S5, the temperature T detected by the temperature sensor 10 is changed to the variable n.
It is determined whether or not the test temperature Tn corresponding to is reached, and if the test temperature Tn is not reached, the determination is repeated. Sample temperature T
If the temperature reaches the test temperature Tn, the process proceeds to step S6, and the measured volume value Va is read from the volume calculator 14. In the next step S7, the volume error Vs corresponding to the pressure Pt and the temperature Tn is obtained from the diagram showing the correlation between the volume error due to the strain of the apparatus and the sample pressure P and the temperature T. In the next step S8, the volume of wood metal F per unit mass (hereinafter,
The specific volume vf corresponding to the pressure Pt and the temperature Tn is obtained based on the diagram showing the correlation between the specific volume) v and the pressure P and the temperature T, and the process proceeds to step S9.

In step S9, the previously determined specific volume vf
And the mass Wf of the wood metal F are multiplied to obtain the volume Vf of the wood metal F. In the next step S10, the volume error Vs and the volume Vf of the wood metal F are divided from the volume measurement value Va to obtain the volume Vr of the sample R, and the result is output. After the volume Vr of the sample R is obtained as described above, it is determined in step S11 whether or not the current variable n is equal to the designated measurement number m. When the result in step S11 is negative, the process returns to step S4, and the volume measurement is repeated in the same procedure until the variable n reaches the measurement count m. If step S11 is affirmed, the process ends. With such a procedure, as shown in FIG. 5, the horizontal axis represents temperature T and the vertical axis represents volume V.
(Or specific volume) is created. If the test pressure Pt is changed and the above procedure is repeated, a plurality of TV diagrams corresponding to the pressure can be obtained.

According to the above procedure, the strain error Vs corresponding to the pressure Pt and the temperature Tn when the volume measurement value Va is measured in step S6 is calculated in step S7, and
Volume V of wood metal F corresponding to pressure Pt and temperature Tn
Since f is calculated in steps S8 and S9 and these are subtracted from the volume measurement value Va in step S10, the volume Vr output from the data processing device 15 is the true value of the sample R that does not include the distortion error or the volume of the wood metal F. It becomes the volume of. Moreover, in this embodiment, the error Vs due to the distortion and the wood metal F
Therefore, even if the actual mass Wf of the wood metal F is different from the mass (unit mass in the embodiment) used when the diagram used in step S8 is calculated, step S9 is calculated. It suffices to multiply by the mass ratio at, and there is no need to create and input a diagram corresponding to the mass of the Woodmetal F. Therefore, the amount of data stored in the device is significantly reduced as compared with the conventional device, and the input work is greatly saved.

Various methods may be used to obtain the diagrams used in steps S7 and S8. However, as an example, a method of performing the test by changing the mass of the measurement auxiliary material in the same device as described below is used. is there.

Wood metal having a mass of W ₁ and W ₂ has a specific pressure P
When the volume occupied at the specific temperature T is measured by the same device and the volume measurement values V ₁ and V ₂ are obtained, if the strain errors contained in these are set to δ ₁ and δ ₂ , the measurement auxiliary material The true volumes Vr ₁ and Vr ₂ are Vr ₁ = V ₁ −δ ₁ (1) Vr ₂ = V ₂ −δ ₂ (2) Here, since the strain errors δ ₁ and δ ₂ under the same pressure and the same temperature in the same device are the same, according to the equations (1) and (2), Vr ₁ −Vr ₂ = V ₁ −V ₂ (3) From this, the specific volume v of the measurement auxiliary material is v = (V ₁ −V ₂ ) / (W ₁ −W ₂ ) = (Vr ₁ −Vr ₂ ) / (W ₁ −W ₂ ) ... (4) Becomes

Next, from equations (1) and (4), the distortion error δ (=
δ ₁ , δ ₂ ) is δ = V ₁ −Vr ₁ = V ₁ −v · W ₁ = (V ₂ · W ₁ −V ₁ · W ₂ ) / (W ₁ −W ₂ ) ... (5) Becomes In this way, if the mass of the measurement-assisting material is changed and the test is conducted under the same pressure and temperature with the same device, the strain error with respect to the pressure and temperature at that time and the specific volume of the measurement-assisting material can be obtained respectively. Repeating similar measurements for pressure and temperature will give the required diagram.

In the embodiment, the vertical axis of the diagram used in step S8 is the specific volume of wood metal. However, if the reference mass of the vertical axis is clear, the mass of wood metal and the like actually mixed in is determined. Since the volume can be easily corrected by the ratio of, the convenient mass such as the mass per 100 g may be used as a reference.

The measurement auxiliary material is not limited to wood metal, but may be changed appropriately such as silicon oil. In addition, the present invention is 1
The present invention is not limited to the case where only two kinds of measurement auxiliary materials are mixed, but the case where two or more kinds of measurement auxiliary materials are mixed at the same time is applied, and the properties of the measurement auxiliary material are not limited to those having a melting point lower than that of the sample. For example,
A material such as wood metal having a larger specific gravity than the sample may sink to the lower part of the sample and may not function as a friction preventer between the cylinder inner wall and the sample. As shown, it is conceivable that the granular resin sample R is covered with a thin film M having a higher melting point and a lower friction coefficient than the sample R, and then stored in the sample filling hole 4a filled with the wood metal F. In this case, as shown by the chain double-dashed line L in FIG. 5C, a diagram showing the correlation of pressure, volume and temperature of the thin film M is prepared, and the thin film M is obtained in the same manner as when the volume of the wood metal F is obtained. The volume of the sample can be accurately determined by determining the volume of.

In the above embodiment, the data processing device 15 also serves as the first and second correction amount calculating means and the sample volume calculating means.

[0024]

As described above, according to the present invention,
Since the volume error due to the strain of the device and the volume of the measurement auxiliary material are obtained from different diagrams, the correlation of the pressure, volume and temperature of the measurement auxiliary material should be checked when the mixed amount of the measurement auxiliary material changes. The true volume of the measurement auxiliary material can be obtained only by correcting the volume obtained from the diagram shown in proportion to the amount of change in mass, and it is necessary to obtain and store the line diagram according to the mass of the measurement auxiliary material. There is no. Therefore, the amount of data input to the device is significantly reduced, and the data input work is also significantly labor-saving.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a cylinder of a measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an external appearance of a main part of a measuring apparatus according to an embodiment of the present invention.

3 is a flowchart showing a processing procedure in the data processing apparatus of FIG.

FIG. 4 is a view showing a state in which two types of measurement auxiliary materials are put into the cylinder.

FIG. 5 is an example of a diagram for explaining the operation of the present invention, in which (A) is a measured volume value of a sample and a true volume and pressure,
A diagram showing the correlation with temperature, (B) a diagram showing the correlation between the volume error due to the strain of the device and the pressure and temperature, (C)
FIG. 3 is a diagram showing a correlation between pressure, volume and temperature of a measurement auxiliary material.

FIG. 6 is a diagram for explaining a correction procedure of a conventional device.

[Explanation of symbols]

 1 Device main body 4 Cylinder 8 Piston 15 Data processing device F Woodmetal R Sample

Claims (1)

(57) [Claims] 1. A pressure for measuring the volume of the sample while changing at least one of the pressure and the temperature of the sample to obtain a correlation between the pressure, the volume and the temperature of the sample,
In a volume and temperature characteristic measuring device, based on a diagram showing the correlation between the error amount that the strain of the device gives to the measured value of the volume and the pressure and temperature of the sample, the pressure and temperature at the time of the volume measurement are measured. First correction amount calculating means for obtaining an error amount of the measurement value, a diagram showing the correlation between the pressure of the measurement auxiliary material mixed in the sample, the volume per specific mass and the temperature, and the actually mixed measurement Second correction amount calculation means for obtaining the true volume of the measurement auxiliary material at the pressure and temperature during the volume measurement based on the mass of the auxiliary material; and the first correction amount calculation means for calculating the true volume of the measurement auxiliary material. Error amount,
Correcting the measured value of the volume based on the true volume of the measurement auxiliary material calculated by the second correction amount calculation means,
A device for measuring pressure, volume and temperature characteristics, comprising: a sample volume calculating means for determining the true volume of the sample.