JP2013036751A - Volume measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a volume measuring device capable of performing measurement efficiently in a short time and with high accuracy.SOLUTION: A volume measuring device 1 comprises: sealed space forming means 3 for forming a sealed space by housing an object 2 to be measured; capacity changing means 4 for changing a capacity of the sealed space; pressure measuring means 5 for measuring pressure of gas in the sealed space; and a control unit 12 for operating the capacity changing means 4 to determine a volume value of the object 2 to be measured on the basis of a pressure measurement value obtained by the pressure measuring means 5 before and after changes in capacity. The device is configured to have a container 31 where an opening is formed by the sealed space forming means 3 and a closing member 32 for closing the opening via a seal member 33 and to have the control unit 12 increase capacity of the sealed space in a plurality of separate steps by the capacity changing means 4 to determine a volume value of the object 2 to be measured on the basis of a pressure measurement value obtained before and after changes in capacity in second and succeeding steps that are performed after pressure drop in the sealed space caused by changes in capacity of a first step.

Description

  The present invention relates to a volume measuring apparatus for measuring the volume of a measurement object by changing the volume of a sealed container containing the measurement object and detecting a pressure change inside the container.

  Conventionally, density has been used as one of the indexes for quality evaluation of vegetables and fruits. As a method for measuring such a density, there is an Archimedes method in which an object to be measured is immersed in a liquid and the degree of buoyancy is evaluated.

  However, when this method is used, it takes time to measure the amount of liquid, and it takes time to wipe off the liquid adhering to the surface of the object to be measured after the measurement. Depending on the type, there is a problem that quality deterioration such as corruption tends to occur.

  Therefore, as a method for obtaining the density without using a liquid, it is conceivable to calculate the density by obtaining the volume and mass of the object to be measured. For example, Patent Document 1 below discloses a method for obtaining the volume of an object to be measured using a change in pressure of a gas without using a liquid.

  It measures the volume of solids or liquids present in a constant volume measuring vessel, so that the solid or liquid based on pressure changes caused by inserting or removing gas in the measuring vessel in a substantially sealed condition. A method for measuring the volume of a liquid and a measuring apparatus for realizing the method are described. According to this apparatus, the volume can be measured without immersing the object to be measured in the liquid while having a simple configuration, and the density can be obtained by separately measuring the weight.

  The volume measuring device disclosed in Patent Document 1 uses an urging force of a spring for a sealing mechanism portion provided with a sealing material on the surface to form the above-described sealed state. It is comprised so that it may contact | abut. In such a volume measuring device using the pressure change of the gas in the measurement container, it is necessary that the inside of the measurement container is securely sealed and the gas is shut off from the outside. This is very important for improving measurement accuracy.

JP-A-6-26906

  However, in the volume measuring apparatus, the sealing mechanism for closing the opening of the measuring container is as simple as described above, and it is uncertain whether or not a sealed state is actually realized. End up. For example, if dust is caught between the opening of the measurement container and the seal mechanism, a gap may be generated correspondingly, and gas may flow out or flow in from the outside.

  In addition, even if a sealed state can be formed before the start of measurement, the pressure inside the measurement container will increase when the gas is inserted into the measurement container during measurement. If it exists, there exists a possibility that a clearance gap may arise between the opening part of a measurement container, and a sealing mechanism part, and gas may flow out outside.

  As described above, the volume measuring device according to Patent Document 1 has a configuration that cannot reliably seal the measurement container that houses the object to be measured, and thus accurately measures the pressure change of the gas inside the measurement container. There is a problem that the measurement accuracy becomes low.

  In addition, when attempting to perform an accurate measurement while avoiding the above problems, the measurer must carefully work so that there is no gap between the opening of the measurement container and the seal mechanism when preparing the device. It is necessary to proceed, and during the measurement, it is necessary to constantly pay attention to the outflow of gas from the inside of the measuring container to the outside or the inflow of gas from the outside into the measuring container. Therefore, it takes time for preparation and measurement work, and there arises a problem that work efficiency is lowered.

  An object of the present invention is to effectively solve such problems. Specifically, the present invention can provide a volume measuring apparatus with high measurement accuracy in addition to being able to efficiently perform measurement work in a short time. With the goal.

  In order to achieve this object, the present invention takes the following measures.

  That is, the volume measuring device according to the present invention includes a sealed space forming unit capable of forming a sealed space with an object to be measured inside, a volume changing unit for changing the volume of the sealed space, and the sealed Pressure measuring means for measuring the pressure of the gas in the space and the volume changing means are operated, and the object to be measured is based on pressure measurement values obtained from the pressure measuring means before and after the volume change by the volume changing means. A controller for determining a volume value of the container, wherein the sealed space forming means includes a container in which an opening is formed, and a closing member that closes the opening through a seal member. And the control unit increases the volume of the sealed space in a plurality of stages by the volume changing means, and the second stage is performed after the pressure in the sealed space is reduced by the volume change of the first stage. Characterized in that it is configured to based on the pressure measurements obtained before and after the subsequent volume change determining the volume values of the object to be measured.

  If comprised in this way, even if the adhesiveness between the opening part of a container, and a sealing member and a closing member is in a state inadequate, it will be opened by the fall of the pressure in the sealed space accompanying the volume change of a 1st step. Adhesiveness between the portion, the seal member, and the closing member is enhanced, and the gas inside the sealed space can be almost certainly blocked from the outside gas. Since the volume value is determined based on the pressure measurement values measured before and after the second and subsequent volume changes performed thereafter, the accuracy of volume measurement can be improved. Further, in the preparation stage of the measurement work, it is necessary to perform the measurement because the measurement can be performed even if the work is performed without paying attention to the close contact state between the opening and the sealing member and the closing member. Time can be shortened.

  In addition, in order to further improve the above-mentioned effect of improving the efficiency and measurement accuracy of the measurement work, it is determined whether the gas is properly blocked between the gas inside the sealed space and the outside gas, It is preferable to prompt the operator to perform re-measurement when blocking is not possible and proper measurement is not possible, until the second stage volume change is started after the first stage volume change. The measured pressure value of the gas in the sealed space obtained by the pressure measuring means during the interval exceeds a predetermined value, or the sealed value obtained by the pressure measuring means until a predetermined time elapses from the volume change at each stage. It is preferable that the control unit includes a measurement error determination unit that outputs a measurement error signal when the amount of change in the pressure measurement value of the gas in the space exceeds a predetermined value.

  In addition, the volume measurement value is affected by equipment characteristic factors such as deformation of containers and pipes accompanying internal pressure changes, and external factors such as atmospheric pressure, temperature, and humidity. Since it is desirable to obtain calibration data under known conditions in advance, the relationship between the pressure measurement value by the pressure measuring means and the volume value of the object to be measured is a predetermined relationship according to the device characteristics and environment. A calibration mode for obtaining calibration data for performing correction, and a state in which the control unit does not contain the object to be measured in the sealed space, or a calibration member having a known volume value A calibration data creation unit for creating calibration data based on the pressure measurement value obtained by the pressure measurement means in the state, and a calibration data for storing the calibration data created by the calibration data creation unit. And a volume of the object to be measured based on the calibration data stored in the calibration data storage unit in addition to the pressure measurement value obtained from the pressure measurement means by the volume determination unit. Suitably, the value is determined.

  Furthermore, in order to further increase the measurement accuracy, it is preferable that the pressure measurement at the time of obtaining calibration data is performed in the same operation as in the actual measurement. However, when the volume of the sealed space is increased in a plurality of stages through the volume changing means, based on the pressure measurement values obtained before and after the volume change performed after the volume change of the first stage, It is still more preferable that the calibration data is created in the volume determination unit.

  Further, in order to be able to change the volume in the sealed space easily and accurately, the volume changing means is connected to a pipe that is attached to the container or the closing member and communicates with the inside of the sealed space. It is preferable that the cylinder is provided with a cylinder and a motor for reciprocating the piston constituting the cylinder.

  According to the present invention described above, it is possible to efficiently perform measurement work and to provide a volume measuring device with high measurement accuracy.

The system block diagram of the volume measuring apparatus which concerns on one Embodiment of this invention. The schematic diagram at the time of accommodating a to-be-measured object in the inside of the container which comprises the volume measuring apparatus. The schematic diagram which shows the operation | movement at the time of measuring using the same volume measuring apparatus. The flowchart which shows the process sequence at the time of measuring using the volume measuring apparatus. The graph which showed the example of the pressure change of the gas in the container at the time of measuring using the same volume measuring apparatus. The schematic diagram which shows the example which deform | transformed the apparatus part of the volume measuring apparatus of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the volume measuring apparatus 1 of this embodiment largely controls the operation of the device unit 11 and the device unit 11 and calculates the volume value based on the measurement data obtained by the device unit 11. It is comprised from the control part 12 which performs. The control unit 12 is connected to an input unit 70, a display unit 75, and a notification unit 77 for exchanging information with the measurer.

  The instrument unit 11 includes a sealed space forming unit 3 that forms a sealed space in a state in which the DUT 2 is accommodated, a volume changing unit 4 that changes a volume inside the sealed space, and a gas in the sealed space. It comprises pressure measuring means 5 for measuring the pressure of a certain air 13.

  Further, the sealed space forming means 3 includes a base 32 as a closing member configured in a plate shape, a seal member 33 provided on the base 32, and a rectangular parallelepiped shape so as to cover the object 2 to be measured. And a container 31 provided.

  As shown in FIG. 2, when the device under test 2 is placed inside the instrument unit 11 for measuring the volume, the device under test 2 is placed on the upper surface 32 a of the base 32, and A container 31 having an opening 31 a on the side is covered from above, and is brought into contact with the upper surface 32 a of the base 32 via a seal member 33. Since the container 31 is provided with the volume changing means 4 and the pressure measuring means 5 connected to each other, they are configured to move in an integrated state.

  In addition, the seal member 33 is formed of an elastic body such as silicon rubber, and has a shape that can be closely attached over the entire circumference of the opening 31 a of the container 31, so that the opening of the container 31 is combined with the base 32. It is comprised so that the whole 31a can be closed. Therefore, the base 32 closes the opening 31 a of the container 31 through the seal member 33 by bringing the container 31 into contact with the upper surface 32 a of the base 32 through the seal member 33 as described above. Therefore, a sealed space in which air 13 as a gas is confined is formed.

  Returning to FIG. 1, the volume changing means 4 as a component of the device unit 11 includes a cylinder 41, a motor 42 for reciprocating a piston constituting the cylinder 41, the inside of the cylinder 41, and the inside of the container 31. And a cylinder pipe 43 communicating with each other. A stepping motor is used as the motor 42 and operates according to a command from the control unit 12 so that the internal volume of the cylinder 41 can be finely changed by moving the piston of the cylinder 41. Since the cylinder 41 is in communication with the inside of the container 31 through the cylinder pipe 43, by moving the cylinder 41, the air 13 is sent into the container 31 or the air 13 is sucked from the inside of the container 31. It is possible to do.

  Further, the pressure measuring means 5 as a constituent element of the device unit 11 includes a pressure gauge 51 and a pressure gauge pipe 52 that communicates the pressure gauge 51 and the inside of the container 31. The pressure gauge 51 is configured so as to be able to measure the pressure of the air 13 inside the container 31, and is supplied with power from a power supply unit (not shown), and the pressure measurement value is obtained by an analog or digital electric signal. It can be output to the control unit 12.

  As described above, when the opening 31a (see FIG. 2) of the container 31 is closed by the base 32 as a closing member, a sealed space is formed. The space is a space formed between the container 31 and the base 32 plus the internal volumes of the cylinder 41, the cylinder pipe 43, the pressure gauge 51, and the pressure gauge pipe 52. Among these, the internal volumes of the cylinder pipe 43, the pressure gauge 51, and the pressure gauge pipe 52 can be regarded as substantially constant values, but the internal volume of the cylinder 41 is changed by the operation of the piston as described above. Therefore, the internal volume of the sealed space is changed accordingly.

  In addition, the sealed space described in the present invention refers to the space itself formed as described above, and it is a problem whether or not a true seal can be realized by being completely blocked from the outside. It is not a thing.

  The volume measuring device 1 changes the volume of the sealed space formed by the container 31 and the like as described above by the operation of the cylinder 41 constituting the volume changing means, and the air 13 inside the container 31 before and after the volume change. The volume of the object 2 to be measured is to be measured by measuring the pressure.

  Therefore, based on the instruction from the measurer given from the input unit 70, the control unit 12 is configured as follows in order to operate the device unit 11 and to output a result of appropriate calculation from the measured value. Has been.

  First, through the input unit 70 connected to the control unit 12, a command for changing the operation mode, information necessary for measurement and calculation, and a specific operation command are given to the basic command unit 71. In the basic command unit 71, based on the command given from the input unit 70, in either the calibration mode or the measurement mode, an operation command, a command to perform calculation and display based on the measured value is given to each unit. Is configured to give. The calibration mode and the measurement mode are selected by the measurer and can be designated through the input unit 70. The basic command unit 71 gives an operation command corresponding to the mode to each unit.

  The calibration mode is for eliminating the measurement error by grasping the influence due to factors such as room temperature, atmospheric pressure, humidity, aging of the equipment unit 11, etc. prior to the actual volume measurement. It can be said that this is an operation mode for obtaining calibration data for correcting the relationship between the value and the volume value of the object to be measured to be a predetermined relationship according to the device characteristics and environment.

  When this calibration mode is used, a calibration member formed of an aluminum block having a known volume value is placed in place of the object to be measured 2 in place of the object 31 or in place of the object to be measured 2. In this state, calibration data is created by performing the same operation and measurement as in the volume measurement. The measurer inputs the volume value from the input unit 70 when there is no object to be accommodated therein, and when the calibration member is accommodated. When the calibration members to be used are limited, the volume values may be stored in the internal memory, and selected from among them and called up.

  In the volume measurement in the measurement mode, the basic command unit 71 outputs a command to the motor control unit 72 in order to change the volume in the sealed space. The motor control unit 72 controls the operation of the motor 42 by setting a specific command value so as to match the command.

  Further, the basic command unit 71 outputs a command to the pressure measurement unit 73 at a timing when pressure measurement is required, and the pressure measurement unit 73 displays the pressure measurement value obtained by the pressure gauge 51 at that time. It can output to the volume determination unit 74.

  In addition to the pressure measurement value input from the pressure measurement unit 73, the volume determination unit 74 is given the volume change data provided from the basic command unit 71 and the calibration data stored in the calibration data storage unit 79. Thus, the volume value of the device under test 2 is calculated and determined and output. Note that the volume value of the DUT 2 can be determined by selecting from the data table according to the pressure measurement value without performing the calculation.

  Further, it is determined from the time data of the volume change obtained from the basic command unit 71 and the pressure measurement value obtained from the pressure measurement unit 73 whether or not the sealed state is properly formed. When the determination is made, a measurement error determination unit 76 that outputs a measurement error signal is provided. When the measurement error signal is output, the display unit 75 connected to the control unit 12 displays a measurement error. At the same time, the notification unit 77 connected to the control unit 12 is notified by means of error sound, lighting of an error lamp, or the like. By these means, it is possible to notify the measurer of the occurrence of an error.

  The display unit 75 is configured not only to display an error but also to display a volume value obtained from the volume determination unit 74 and various operation situations obtained from the basic command unit 71.

  When acquiring calibration data, a command for executing a calibration mode is given from the input unit 70, and a command corresponding to the command is output from the basic command unit 71 to each unit, and necessary for the calibration data creation unit 78. You are instructed to capture the correct data and create calibration data. At this time, similarly to the normal volume measurement, the cylinder 41 is operated through the motor 42 by the motor control unit 72, and the pressure measurement result at that time is input to the calibration data creation unit 78 through the pressure measurement unit 73. .

  The calibration data creation unit 78 creates calibration data based on the volume data of the calibration member obtained from the basic command unit 71 and the pressure measurement value obtained through the pressure measurement unit 73. More accurate calibration data may be created by repeating the same measurement using calibration members having different masses.

  The calibration data created as described above is output to the calibration data storage unit 79 and stored therein. As described above, the calibration data is called and used by the volume determination unit 74 in actual volume measurement, so that the volume value can be obtained with higher accuracy.

  Here, the principle of measuring the volume of the DUT 2 using the change in gas pressure as described above will be described.

  First, as shown in FIG. 1, the device under test 2 having a volume Vx is accommodated in a sealed space whose internal volume is V0. At this time, the volume of the air 13 confined in the sealed space is represented by (V0−Vx). Further, the pressure of the air 13 in the sealed space at this time is represented by P 0 and is measured by the pressure gauge 51.

  Thereafter, as shown in FIG. 3A, the cylinder 41 is operated to increase the internal volume in the sealed space to V1. At this time, the volume of the air 13 confined in the sealed space is represented by (V1-Vx). Further, the pressure of the air 13 in the sealed space at this time is represented by P1.

In this way, when the volume in the sealed space changes, the condition that the sealed state inside the container 31 is completely maintained and there is no exchange of air with the outside, and there is no temperature change. Then, the following relation is derived from the well-known Boyle's law.
P0 (V0−Vx) = P1 (V1−Vx) ………………………… Formula (1)

Furthermore, since the increase amount of the volume in the sealed space can be accurately given by driving the motor 42 as the increase amount ΔVa of the inner volume of the cylinder 41,
V1 = V0 + ΔVa ………………………………………………………… Formula (2)
There is a relationship.

From the above formulas (1) and (2), the following relational expressions are obtained.
P0 (V0−Vx) = P1 (V0 + ΔVa−Vx) …………………… Formula (3)

By transforming this, Vx is obtained as follows.
Vx = V0−ΔVa · P1 / (P0−P1) ………………………… Formula (4)

Further, the above relationship is based on the case where the internal volume of the cylinder 41 is further increased by ΔVb and the internal volume of the sealed space is increased to V2 as shown in FIG. 3B with reference to the state of FIG. Also applies. Therefore, when the pressure of the internal air 13 at this time is measured as P2, the relationship of the following equation is obtained.
Vx = V1−ΔVb · P2 / (P1−P2)... (5)

  If the air 13 confined in the sealed space is almost certainly shut off from the outside, the volume Vx of the DUT 2 is obtained in the same manner according to Equation (4) and Equation (5). It is possible. Further, the volume change relationship similar to the equations (4) and (5) can be obtained in any number of steps as long as the stroke of the cylinder 41 permits, and if the change amount of the volume and the internal pressure are known. The volume Vx of the DUT 2 can be obtained using any volume change relationship. Utilizing these properties, the same DUT 2 is set in the container 31, and the measurement is repeated for the same DUT 2 in a plurality of stages. It is also possible to reduce the error by averaging the obtained volume Vx.

  In addition, in obtaining the volume Vx of the object 2 to be measured, the method of using the pressure change at that time while increasing the volume in the sealed space has been described, but in principle, the sealed space and the outside are blocked. Since the relationship according to Boyle's law is established as long as it is sufficient, the volume Vx of the DUT 2 can be obtained in the same manner while reducing the volume in the sealed space.

  However, when measurement is performed while reducing the volume in the sealed space, the pressure in the sealed space increases, and thus the seal with the outside tends to be insufficient. In the volume measuring apparatus 1 according to the present embodiment, as shown in FIG. 1, a sealed space is formed by contacting the base 32 via the seal member 33 using the container 31. It becomes the structure sealed by the dead weight by the member connected with this.

  Therefore, it is possible to easily prepare the device, but because it is not configured to perform strong sealing by applying external pressure by bolting etc., sealing may be insufficient depending on measurement conditions Is assumed. For example, if the measurement is to be performed in the direction of reducing the volume in the sealed space as described above, an upward force acts on the container 31 to create a gap between the seal member 33 and the internal space. Air 13 may leak out.

  For this reason, the pressure measuring device 1 of this embodiment reduces the internal volume of the cylinder 41 before the start of measurement, and is operated in the direction of increasing the internal volume of the cylinder 41 by ΔVa with the start of measurement. . By doing so, since the pressure inside the container 31 is reduced and a downward force acts on the container 31, the adhesion between the container 31 and the seal member 33 is further increased so that a strong seal can be achieved. Become.

  By operating in this way, even when the seal between the container 31 and the base 32 is insufficient at the stage of measurement preparation, the sealing force automatically increases and the outside is almost certainly shut off. The sealed state made can be formed. For example, even if there is a gap that cannot be determined by the measurer due to the biting of dust or misalignment between members at the initial stage, there is a slight inflow of air, but the internal pressure decreases. A sealed state can be formed almost certainly.

  Therefore, in the volume measuring apparatus 1 of the present embodiment, in the measurement, the internal volume of the cylinder 41 is increased so that the pressure in the sealed space is reduced, and the internal volume of the cylinder 41 is reduced. The increase can be performed in a plurality of stages, an appropriate sealed state is formed by increasing the internal volume in the first stage, and the volume is measured by a change in pressure accompanying an increase in the internal volume after the second stage. is there. This makes it possible for the measurer to proceed with the work without paying attention to whether or not the sealed state has been properly formed at the stage of preparing the apparatus, so that the work efficiency is increased.

  Specifically, the measurement is advanced according to the flowchart shown in FIG. The change in the pressure of the gas in the sealed space at this time is shown in FIG.

  Hereinafter, a specific measurement operation will be described with reference to FIGS. 4 and 5.

  First, the measurer gives an operation command after setting the device under test 2 (see FIG. 1) in the apparatus.

  Then, first, the pressure (P0) in the sealed space in the initial state is measured (ST001). This pressure (P0) is approximately equal to the atmospheric pressure.

  After the measurement is completed, the cylinder 41 (see FIG. 1) is operated as a first-stage volume change to increase the volume in the sealed space by ΔVa (ST002). At this time, the pressure in the sealed space decreases from point A to point B in FIG. At point B, the operation command given to the cylinder 41 (see FIG. 1) is stopped, but the pressure slightly increases due to deformation and stabilization of each member.

  At this time, if the seal is insufficient, the internal pressure becomes unstable and changes so as to increase toward the initial pressure P0 substantially equal to the atmospheric pressure. Therefore, it is determined whether the amount of change in the pressure is within a predetermined threshold value (ST003), and if it exceeds the threshold value, an error determination is made and an error is notified. (ST012). Specifically, a pressure difference between the pressure value that changes every moment is obtained as a change amount based on the pressure value at a point B in FIG. 5, and the change amount becomes a predetermined value or less. If this is exceeded, an error is determined.

  The determination of whether or not the amount of change in pressure is within a predetermined value is repeated until the predetermined time t1 elapses after the operation of the cylinder 41 (see FIG. 1) is completed (ST004), and the pressure at the time when the predetermined time t1 elapses is P1. Is measured and recorded (ST005).

  At this time, it is determined whether or not the pressure difference (P0−P1) from the initial time point is equal to or greater than a threshold value set in advance as a predetermined value (ST006). The fact that the pressure difference (P0-P1) is small means that the seal is hardly formed. Therefore, even when the pressure difference (P0-P1) is smaller than the threshold value, error determination is made and an error is notified. (ST012). Since P0 is substantially equal to the atmospheric pressure, the determination whether the pressure difference (P0-P1) is equal to or greater than a predetermined value is substantially equal to the determination whether P1 is actually equal to or less than the predetermined value. I can say that. Therefore, these are synonymous, and are generally treated as error determinations when the pressure P1 measured at a predetermined time t1 has exceeded a predetermined value.

  If no error determination is made, the cylinder 41 (see FIG. 1) is operated as a second-stage volume change to continue the measurement, and the volume in the sealed space is increased by ΔVb (ST007). Even in this case, as in the case after the volume change in the first stage, it is determined whether the pressure change amount is within a predetermined threshold value (ST008), and the threshold value is exceeded. In this case, an error is notified (ST012). This error determination is also repeated until a predetermined time t2 has elapsed from the completion of the operation of the cylinder 41 (see FIG. 1) (ST009), and the pressure at the time when the predetermined time t2 has elapsed is measured as P2 and recorded (ST010). ).

  In this way, the device automatically determines whether the sealed state is properly formed, and if it is in an inappropriate state, a measurement error signal is issued. Therefore, pay special attention to device preparation. Even if the work is proceeded without any problem, no problem occurs in the measurement, and the work efficiency becomes higher.

  Based on the data of P1 and P2 obtained in this way and the data of V1 and ΔVb input in advance, the volume Vx is obtained by Equation (5) (ST011).

  Since the calculation of the volume Vx is performed using the pressure measurement value when it is determined that the sealed state can be appropriately formed as described above, the measurement accuracy can be improved.

  In addition, when the calculation formula for calibration is obtained in advance by the calibration mode described above, the volume Vx can be obtained with higher accuracy without inputting the data of V1 and ΔVb.

That is, based on Equation (5), which is an ideal state equation, an actual equation that takes into consideration the actual temperature, atmospheric pressure, humidity, error in the internal volume of the sealed space, error in the cylinder volume, and deformation of each part. Can be approximated as follows.
Vx = a + b · P2 / (P1-P2) ……………………………… Formula (6)
Here, a and b are coefficients that need to be obtained in the calibration mode.

  As described above, in the calibration mode, the measurement operation is performed a plurality of times in a state in which the object to be measured is not inserted or a state in which a calibration member formed of an aluminum block having a known volume value is used instead of the object to be measured. Thus, the coefficients a and b in Equation (6) are obtained. In this way, if the coefficients a and b are obtained in advance, the volume Vx can be obtained by Equation (6) only by reproducing P1 and P2 while reproducing the same operation.

Further, when higher accuracy is required than Expression (6), it is conceivable to use an approximate expression in which terms proportional to P1 and P2 are increased as follows.
Vx = a + b * P2 / (P1-P2) + c * P1 + d * P2 Expression (7)

  Here, a to d are coefficients that need to be obtained in the calibration mode.

  In this case, since there are more unknown coefficients than in the case of Equation (6), there is a disadvantage that the time required in the calibration mode becomes longer. However, after the coefficients a to d are determined, the accuracy is higher. There is an advantage that a high measurement can be performed.

  Note that the measurement in the calibration mode described above is required to obtain the same accuracy as the actual measurement in order to obtain high accuracy. Therefore, it is important to make the control command to the cylinder 41 the same in order to perform the same volume change as in the actual measurement, to perform the operation divided into the same number of steps, and to make the pressure value measurement timing the same. It is.

  As described above, the internal volume of the cylinder 41 in FIG. 1 is changed in two stages, the pressure in the sealed container before and after the volume change in the second stage is measured, and the calculation using this is performed. Thus, the volume Vx of the DUT 2 can be obtained with high accuracy.

  Further, as described above, by increasing the internal volume of the cylinder 41 (see FIG. 1) to three or more stages, not only the volume Vx is obtained from the pressure before and after the volume change of the second stage, but the volume of the third stage. By measuring the pressure before and after the volume change at each stage, such as before and after the change, and before and after the volume change at the fourth stage, the volume Vx can be obtained. Further, by averaging these, the volume Vx can be obtained with higher accuracy.

  As described above, the volume measuring apparatus 1 according to the present embodiment changes the volume of the sealed space and the sealed space forming means 3 that can form the sealed space in a state where the DUT 2 is housed inside. The volume changing means 4, the pressure measuring means 5 for measuring the pressure of the gas in the sealed space, and the volume changing means 4 are operated, and obtained from the pressure measuring means 5 before and after the volume change by the volume changing means 4. A control unit 12 that determines a volume value of the object 2 to be measured based on a measured pressure value, and a container 31 in which the sealed space forming means 3 is formed with an opening 31a; A closing member 32 for closing the opening 31a via a seal member 33, and the control unit 12 increases the volume of the sealed space in a plurality of stages by the volume changing means 4; Of stage The volume value of the device under test 2 is determined based on the pressure measurement values obtained before and after the volume change after the second stage performed after the pressure in the sealed space is reduced by the product change. It is characterized by that.

  Since it is configured in this manner, even if the adhesion between the opening 31a of the container 31 and the sealing member 33 and the base 32 which is a closing member is insufficient in the device preparation stage, the first Due to the decrease in pressure in the sealed space accompanying the change in volume at the stage, the adhesion between the opening 31a, the seal member 33 and the base 32 is enhanced, and the gas inside the sealed space is almost surely blocked from the external gas. State. And the accuracy of volume measurement can be improved by outputting a volume value based on the pressure measurement value measured before and after the volume change after the 2nd stage performed after that. In addition, since the measurement can be performed with high accuracy even if the work is performed without paying attention to the close contact state between the opening 31a and the seal member 33 and the base 32, the time required for the measurement can be shortened. Is possible.

  Further, the measured pressure value of the gas 13 in the sealed space obtained by the pressure measuring means 5 after the first-stage volume change until the second-stage volume change is started exceeds a predetermined value. A measurement error signal is output when the amount of change in the pressure measurement value of the gas 13 in the sealed space obtained by the pressure measurement means 5 exceeds a predetermined value until a predetermined time elapses after the volume change at each stage. Since the measurement error determination unit 76 is configured to be provided in the control unit 12, it is determined whether or not the gas 13 inside the sealed space and the external gas are almost surely shut off. If the measurement cannot be performed properly because the blocking is not performed, the operator can be prompted to perform the measurement again. As a result, the measurement accuracy can be improved.

  Further, a calibration mode for obtaining calibration data for performing correction so that the relationship between the pressure measurement value by the pressure measuring means 5 and the volume value of the object to be measured 2 becomes a predetermined relationship according to the device characteristics and environment. And a pressure measurement value by the pressure measuring means 5 in a state where the control unit 12 does not contain the device under test 2 in the sealed space or a calibration member having a known volume value. A calibration data creation unit 78 that creates calibration data based on the calibration data storage unit 79 that stores calibration data created by the calibration data creation unit 78; 74 is configured to determine the volume value of the DUT 2 based on the calibration data stored in the calibration data storage unit 79 in addition to the pressure measurement value obtained from the pressure measuring means 5. Therefore, calibration data for eliminating the influence of external factors such as atmospheric pressure, temperature, humidity, etc., as well as equipment characteristic factors such as deformation of the container 31 and the pipes 43 and 52 due to internal pressure changes By acquiring and using the data, the pressure measurement value can be corrected, and the accuracy of volume measurement can be further improved.

  Further, when the calibration data creation unit 78 increases the volume of the sealed space through the volume changing means 4 in a plurality of stages, it is obtained before and after the volume change performed after the first volume change. Since the calibration data is created in the volume determination unit 74 based on the measured pressure value, the pressure measurement when acquiring the calibration data is performed in the same manner as in actual measurement. The measurement accuracy can be further increased.

Further, the volume changing means 4 reciprocates a cylinder 41 attached to the container 31 or the closing member 32 and connected to a pipe 43 communicating with the inside of the sealed space, and a piston constituting the cylinder 41. Therefore, it is possible to easily and accurately change the volume in the sealed space, and to improve the accuracy of volume measurement.

The specific configuration of each unit is not limited to the above-described embodiment.

  For example, instead of the air 13 that is a gas contained in a sealed space, another gas such as an inert gas such as nitrogen can be used, which is appropriately selected according to the type of the object to be measured. can do.

  Further, in the above-described embodiment, the calculation is performed to obtain the volume value each time based on the pressure data obtained by the measurement, but the volume value corresponding to the pressure value can be understood. If the data table is stored, the volume value can be quickly grasped and displayed without reading by reading the data corresponding to the pressure measurement value.

  Further, in the above-described embodiment, the volume changing means 4 and the pressure measuring means 5 are configured to be connected to the container 31 side. However, these may be configured to be provided on the base 32 side. Is possible. It is also possible to configure the cylinder pipe 43 and the pressure gauge pipe 52 to be long and elastic so that the cylinder 41 and the pressure gauge 51 are not moved with the movement of the container 31 and the like.

  Furthermore, like the volume measuring device 201 shown in FIG. 6, it is also possible to configure as a container 231 having an opening 231a upward and a lid 232 as a closing member that closes via the opening 231a sealing member 233. It is. Also in this case, similarly to the above-described embodiment, the cylinder 241, the motor 242 that operates the cylinder 241, and the cylinder pipe 243 are provided as the volume changing unit 204, and the pressure gauge 251 and the pressure gauge are used as the pressure measuring unit 205. Piping 252 is provided. The cylinder pipe 243 and the pressure pipe 252 are configured to communicate with the inside of the container from the lower side of the container 231. Even in such a configuration, the same operation and effect can be obtained by performing the same operation as the above-described embodiment.

  Other configurations can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Volume measuring device 2 ... Object to be measured 3 ... Sealed space formation means 4 ... Volume change means 5 ... Pressure measuring means 11 ... Equipment part 12 ... Control part 31 ... Container 32 ... Base (closing member)
33 ... Sealing member 41 ... Cylinder 42 ... Motor 43 ... Cylinder piping 51 ... Pressure gauge 52 ... Pressure gauge piping

Claims (5)

A sealed space forming means capable of forming a sealed space with the object to be measured inside;
Volume changing means for changing the volume of the sealed space;
Pressure measuring means for measuring the pressure of the gas in the sealed space;
A volume measuring unit that operates the volume changing unit and determines a volume value of the object to be measured based on a pressure measurement value obtained from the pressure measuring unit before and after the volume change by the volume changing unit; A device,
A container in which the sealed space forming means is formed with an opening;
A closing member for closing the opening through a sealing member,
The controller changes the volume of the sealed space by the volume changing means in a plurality of stages and increases the volume after the second stage after the pressure in the sealed space is reduced by the volume change of the first stage. A volume measuring apparatus configured to determine a volume value of the object to be measured based on pressure measurement values obtained before and after the step. When the pressure measurement value of the gas in the sealed space obtained by the pressure measuring means exceeds a predetermined value after the volume change of the first stage until the volume change of the second stage is started, or each A measurement error determination unit that outputs a measurement error signal when the amount of change in the pressure measurement value of the gas in the sealed space obtained by the pressure measurement means exceeds a predetermined value until a predetermined time elapses from the volume change of the stage. The volume measuring apparatus according to claim 1, wherein the control unit is provided. A calibration mode for obtaining calibration data for performing correction so that the relationship between the pressure measurement value by the pressure measuring means and the volume value of the object to be measured is a predetermined relationship according to the device characteristics and environment; ,
Calibration data is created based on the pressure measurement value obtained by the pressure measuring means in a state where the control unit does not contain the object to be measured in the sealed space or a calibration member having a known volume value. A calibration data creation unit,
A calibration data storage unit for storing calibration data created by the calibration data creation unit,
The volume determination unit determines a volume value of the object to be measured based on calibration data stored in the calibration data storage unit in addition to a pressure measurement value obtained from the pressure measurement unit. The volume measuring apparatus according to claim 1 or 2. Pressure measurement values obtained before and after the volume change performed after the first stage volume change when the calibration data creation unit increases the volume of the sealed space through the volume change means in a plurality of stages. The volume measuring device according to claim 3, wherein the calibration data is created in the volume determination unit based on the data. The volume changing means includes a cylinder attached to the container or the closing member and connected to a pipe communicating with the inside of the sealed space, and a motor for reciprocating a piston constituting the cylinder. The volume measuring apparatus according to claim 1, wherein

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