JPH0812099B2 - Volume measuring device and its measuring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application" The present invention relates to an apparatus and method for measuring the content seat of a container.

"Prior Art" Conventionally, as one method for accurately measuring the inner volume of a container, for example, there is a method in which a fluid, particularly water, is put in the container and the amount of water filled until the container is filled is used as the inner volume of the container. .

"Problems to be solved by the invention" In the production process, the volume of a large number of containers is measured one after another using water, and after the measurement, it is necessary to discard the water and dry the containers. Alternatively, recovery equipment is required, and also equipment for drying the container after measurement is required. Furthermore, drainage and recovery facilities need measures to prevent water leakage. As described above, the volume measurement using water requires a large amount of equipment, and there is a drawback that equipment and time for drying are additionally required. Also, dealing with water is complicated in many ways.

Considering volumetric measurement in a similar manner using gas instead of water, the gas is compressible, so volumetric measurement is affected by the pressure of the gas and also by temperature. Further, since gas has a lower viscosity than water, leakage of gas in the container itself and the connection between the container and the measuring device has a great influence. Therefore, it is difficult to measure with high accuracy.

On the other hand, according to JP-A-54-84763, as a volume measuring method using a gas, based on Boyle-Charles' law, a known pressure from a pressure change when a container of known volume is added to an object to be measured. It is described that the volume of an object to be measured is measured. However, this method measures absolute pressure with a pressure gauge, and does not perform relative measurement with the reference volume as the reference volume, so measurement errors are likely to occur, and therefore, for example, the same specifications It is not suitable when highly accurate measurement is required as in the case of measuring the variation in volume of a large number of containers.

The object of the present invention is to avoid the need for a large facility and a drying process, so that it is possible to measure the internal volume of a container using gas and with high accuracy, and especially to measure the variation in the volume of a large number of containers sequentially. A suitable volume measuring device and method are provided.

[Means for Solving Problems] According to the present invention, a volume attached to either one of the measured container side and the reference container side, which substantially balances the measured container side volume and the reference container side volume. Adjusting means, a pair of tanks of equal volume and filled with gases of equal pressure to supply the gas to the measurement container and the reference container, respectively, either the measurement container side or the reference container side Means for giving a known volume change, means for measuring the differential pressure between the pressure in the container to be measured and the pressure in the reference container, and the amount of change in the differential pressure with and without the volume change. A means for calculating the ratio of the differential pressure change to the volume change representing the detection sensitivity from the given volume change amount, and a means for calculating the volume difference of the measured container with respect to the reference container from the differential pressure and the detection sensitivity. To be

Further, the volume measuring method according to the present invention is such that the sensitivity measuring container and the reference container are connected to a pair of tanks having the same volume filled with gas of the same pressure, and the pressure is applied to the sensitivity measuring container after the conduction. The process of measuring the differential pressure from the reference container pressure with and without giving a known volume change to either one of the sensitivity measurement container and the reference container, and the given volume change amount. And a step of calculating the ratio of the differential pressure change to the volume change representing the detection sensitivity from the two measured differential pressures, and connecting the measured container and the reference container to the pair of tanks filled with gas of equal pressure. The step of conducting, the step of measuring the differential pressure between the pressure in the measured container and the reference internal pressure after the conduction, and the measurement of the differential pressure and the detection sensitivity to the reference container That includes a step of calculating the volume difference of the measured vessel.

[Embodiment] Structure of mechanical part Fig. 1 shows a mechanical part of a volume measuring apparatus according to an embodiment of the present invention. In the following description of the embodiments, the gas used for volume measurement is air. .

The compressed air from the compressed air source 11 is branched and supplied to the inlet sides of the two-way solenoid valves SV ₁ and SV ₂ via a pressure reducing valve 12 by piping.
Two-way solenoid valves SV ₁ and SV ₂ have the same internal volume on the outlet side.
Tank 13, 14 VM _T are connected by piping. Tank 13,1
4 is connected to the measurement side pipe 15 and the reference side pipe 16 via the two-way solenoid valves SV ₃ and SV ₄ , respectively. The measuring side pipe 15 and the reference side pipe 16 are respectively connected to the container to be measured 17 through an appropriate jig.
And a reference container 18 is removably attached. Further, a differential pressure detector 19 for measuring the differential pressure between the measurement side pipe 15 and the reference side pipe 16 is connected by a pipe. Further, two-way solenoid valves SV ₅ and SV ₆ for exhaust are connected to the measurement side pipe 15 and the reference side pipe 16, respectively. Pressure reducing valve 1
A pressure gauge 21 for visually checking the adjustment of the air pressure supplied to the tanks 13 and 14 is connected to the outlet side of 2. Further, a pressure detector 22 for detecting the pressure in the tank 13 or 14 which is data required for volume calculation is connected to the tank 13 in this example.

A closed system, which includes the tank 13, the container 17 to be measured, and a pipe portion connected to the tank 13 and through which gas is conducted, is called a measurement side air system. Similarly, a closed system including the tank 14, the reference container 18, and a pipe portion connected to the tank 14 and in which gas is conducted is called a reference side air system. The measurement side pipe 15 is connected with a volume adder 23 for giving a known volume change to the measurement side air system, and the reference side pipe 16 is the total volume of the measurement side air system and the reference side air system. A volume adjuster 24 for adjusting the balance with Volume adder 23
Is composed of, for example, a cylinder and a piston movable therein, and the movable length of the piston can be preset. In this example, the piston is driven by compressed air via a three-way solenoid valve SV ₇ . The volume adjuster 24 is also composed of a cylinder and a piston, and the piston can be moved by rotating the knob 24-1.

In the above configuration, the solenoid valves SV ₃ , SV ₄ , SV ₅ and SV ₆ are closed while the measurement side air system and the reference side air system are left at atmospheric pressure. Next, the solenoid valves SV ₁ and SV ₂ are opened and the tanks 13 and 14 are filled with air at the pressure P _T , and then the solenoid valves SV ₁ and SV ₂ are closed and the solenoid valves SV ₃ and SV ₂ are closed.
It is detected how the differential pressure ΔP detected by the differential pressure detector 19 when V ₄ is opened is represented.

The volumes including the piping of tanks 13 and 14 are equal to each other.
V _T , the volume containing the container 17 to be measured and the measurement side pipe 15 connected to it V _W , the reference container 18 and the reference side pipe connected to it
The volume including 16 is V _M , the pressures of the measurement side and reference side air systems after opening the solenoid valves SV ₃ and SV ₄ are P _W and P _M , respectively, and the differential pressure detected by the differential pressure detector is ΔP. To do.

V _W −V _M = ΔV (1) P _W −P _M = ΔP (2) From Boyle's law, the following formula is established.

V _T · P _T = (V _T + V _M ) · P _M …… (3) V _T · P _T = (V _T ＋ V _W ) · P _W …… (4) Formulas (1) and (2) Substituting into (4) and substituting P _M in equation (3) into the result, Therefore, ΔP is expressed by the following equation.

Assuming that ΔV << (V _T + V _M ) holds, the equation (5) can be approximated as follows.

The following can be understood from the equation (6). That is, since it can be considered that V _T and V _M do not change in the configuration shown in FIG. 1, when there is a volume difference ΔV between the measurement side air system and the reference side air system,
The differential pressure ΔP detected after opening the solenoid valves SV ₃ and SV ₄ is proportional to the product of the initial pressure P _T applied to the tanks 13 and 14 and the volume difference ΔV. The proportional constant K is K = V _T / (V _T + V _M ) ² , and ΔP
If / ΔV = S, then equation (6) can be transformed as follows.

S represents the differential pressure detection sensitivity with respect to the volume difference of the differential pressure detector 19 in the configuration of FIG.

If the initial pressure P _T given to the tanks 13 and 14 is constant, it can be said that the equation (7) is always satisfied in the range where ΔV is sufficiently small. Therefore, for different volume differences ΔV ₁ and ΔV ₂ , S = ΔP ₁ /
If ΔV ₁ and S = ΔP ₂ / ΔV ₂ , the following equation holds.

That is, the differential pressures ΔP ₁ and ΔP ₂ are respectively measured in the case where two containers to be measured which give different volume differences ΔV ₁ and ΔV ₂ are connected, and the sensitivity S can be calculated by the equation (8). Actually, first, the differential pressure ΔP ₁ is measured for _one container to be measured, and then both air systems are opened to the atmosphere, and then the volume adder 23
A known volume ΔV _s is added by and the differential pressure ΔP ₂ is similarly measured. The added volume ΔV _s is the variation (ΔV ₂ −ΔV ₁ ) of the volume difference in the equation (8), and therefore the sensitivity S is calculated from the equation (8).
Can be calculated.

If it is designed so that the inner volumes of the piping of the measurement side air system and the reference side air system are the same, ΔV in equation (1) is
Equal to the volume difference between 17 and the reference container 18. Therefore, when the sensitivity S is calculated as described above with respect to a predetermined initial pressure P _T , the sensitivity S is used to calculate the volume difference ΔV between another measured container 17 having an unknown volume and the reference container 18 as follows. It can be obtained by a formula.

ΔV = ΔP / S (9) If the volumes of the measuring container 17 and the reference container 18 are expressed as VX _w and V _m , the volume V _w of the measuring container 17 is V _w = v _m + ΔV (10) Can be calculated by However, to increase the measurement accuracy, ΔV <<
It is necessary to sufficiently satisfy the condition of (V _T + V _M ), and for that purpose, it is preferable that the volume difference ΔV itself is small. That is,
As the reference container 18, it is desirable to select a container as close as possible to the volume of the container 17 to be measured. If you want to measure the variation of a large number of volumes of the same type produced, select an appropriate one of these containers and use it as the reference container 18, and use the formula (9) It is possible to successively measure the volume difference between the containers.

Generally, the designed container of various designed measured containers is known in advance, so that instead of changing the reference container 19 when changing the type of the measured container to be connected, a desired reference volume is obtained by the volume adjuster 24. You may adjust and set so that it may become substantially the same. By this adjustment, the volume of Δv can be adjusted to the standard container 18
And is equivalent to mounting a reference container having substantially the same volume as the volume of the measured container 17. After the adjustment by the volume adjuster 24, the differential pressures ΔP ₁ and ΔP ₂ are measured as described above, and the sensitivity is calculated from the equation (8). In this case, in the subsequent volume measurement, the internal volume of the reference container 18 is considered to be (V _m + Δv), and the calculation of the equation (10) is performed. That is, the volume of the container 17 to be measured is calculated by V _w = V _m + Δv + ΔV (11).

Differential Pressure Correction In the above description, it has been considered that the container 17 to be measured has no leak, but next, a case where a slight leak occurs will be examined. If there is no leakage, the differential pressure between the measurement side and reference side air systems after opening solenoid valves SV ₃ and SV ₄ at time t ₀ is δ for a short time as shown by the one-dot chain line (a) in FIG. It reaches a certain value in a while and does not change thereafter. When this is observed by the differential pressure detector 19, for example, when a diaphragm type differential pressure detector is used as the differential pressure detector, the response of the displacement of the diaphragm is slow and the transient phenomenon shows the solid line (b). As shown, the rising speed is slow and after the overshoot, it returns to the constant value. However, when there is a slight leak in the container 17 to be measured compared to its internal volume, the pressure in the measurement side air system decreases with time, and the output of the differential pressure detector 19 also changes. Since this change can be regarded as a linear change within a short time, the differential pressure detected changes as shown by the solid line (c) when the response characteristic of the differential pressure detector 19 is also taken into consideration. Immediately after opening the solenoid valves SV ₃ and SV ₄ (for example, after δ), the amount of air leaking to the solid line is so small that it can be ignored, so the differential pressure at that time may be used as the correct differential pressure. The differential pressure is substantially equal to the differential pressure value ΔP _{0 at the} point where the straight line portion of the solid line (C) is extended and the vertical axis (differential pressure) intersects at time t ₀ . Let ΔP ₁ and ΔP ₂ be the pressure differences detected at time points t ₁ and t ₂ in the straight line area of the solid line (c)
₀ is given by the following equation.

If the differential pressure ΔP ₀ obtained by the equation (12) is used instead of ΔP in the equation (9), the volume difference ΔV with respect to the reference container 18 can be obtained with high accuracy even if the measured container 17 leaks. Equation (12) represents the correction of the differential pressure with respect to the leak, but the differential pressure also changes due to causes other than the leak, for example, the temperature decrease of the gas in the closed air system. However, if the change can be considered to be linear within a short period of time, correction is possible as well. After all, the correction by the equation (12) corrects the total differential pressure change due to leakage, temperature change, and all other causes.

Sensitivity correction When the volume differences ΔV of a large number of containers with respect to the reference container 18 are sequentially measured by the formula (9) using the detection sensitivity S of the same value, they are given to the tanks 13 and 14 as apparent from the formula (7) The initial pressure P _T should always be the same from measurement to measurement,
If the pressure of the compressed air source 11 changes, naturally P _T also changes. However, the volumes V _{T of the} tanks 13 and 14 and the volume V _T of the reference volume 18
_{Since M} does not change, the proportionality constant K = V _T / (V _T + V _M ) ² is constant. Therefore tanks 13,14
Initial pressure following equation holds Expressed as 'S detection sensitivity when the _T' P applied to the.

S ′ = − K · P ′ _T (13) The following equation is obtained from the equations (7) and (13).

S ′ = S · P ′ _T / P _T (14) Therefore, in the measurement of each device under test 17, the solenoid valves SV ₁ and SV ₂ are opened and the pressure P ′ _T of the air filled in the tanks 13,414 is detected by the pressure detector. Detected by 22 and corrected the sensitivity by equation (14),
The corrected sensitivity S'may be used instead of the sensitivity S in the equation (9), and it is not necessary to drive the volume adder 23 in advance for each volume measurement to perform the sensitivity measurement.

Structure of Control Unit FIG. 2 shows a control unit for controlling the operation of the volume measuring mechanism unit shown in FIG. 1 and for calculating the detection sensitivity S or the volume difference ΔV etc. by receiving various constants and measured values. It is composed of a computer 31 and other peripheral circuits.
The microcomputer 31 includes a CPU 41, a RAM 42, a ROM 43, an input port 44 and an output port 45, which are connected to each other via a common bus 46.

The outputs of the differential pressure detector 19 and the pressure detector 22 in FIG. 1 are respectively connected to the input side of the multiplexer 32, and one of the differential pressure signal ΔP and the pressure signal P _T is selected and connected to the output side. The output side of the multiplexer 32 is connected to the amplifier 33, and the differential pressure signal ΔP or the pressure signal P _T is amplified. The output of the amplifier 33 is connected to the input of the AD converter to be converted into a digital signal, and is also connected to the monitor meter 35 for analog display. Output of AD converter 34 is an input port
Captured into computer 31 via 44. Input port
44 are set times T ₁ , T ₂ , T ₃ of various timers and a volume adder 23
Keyboard for inputting additional volume ΔV to be set in
Is connected. The output port 45 is connected to a display 37 for displaying the calculation result and a drive circuit 38 for opening / closing the solenoid valves in FIG. ROM43
The operating procedure shown in FIGS. 4 and 5 for measuring the detection sensitivity and measuring the volume difference by the device of the present invention is stored as a program, and the CPU operates the solenoid valves SV ₁ to SV ₁ through the drive circuit 38 in accordance with the program. SV ₇ opening and closing control, selection of signals in the multiplexer 32, display of calculation results on the display 37, detection sensitivity in addition to indication display for the indicator 39,
And perform necessary calculations such as measuring volume.

Operation (sensitivity measurement) As described above, in the present invention, the differential pressure detector 19 is used to measure the measured differential pressure ΔP from the measured container 17 and the reference container.
The volume difference ΔV with respect to 18 is obtained. Before the volume measurement, the detection sensitivity S for the volume difference ΔV of the differential pressure detector 19 is measured. For that purpose, a leak-proof container 17 to be measured is connected to the measurement side pipe 15 as a sensitivity measuring container. Next, a predetermined additional volume Δ given by the volume adder 23
Set V _s , that is, the movable distance of the piston. Further, while monitoring the instruction of the pressure gauge 21, the pressure reducing valve 12 is adjusted and the tank 1
Set the pressure of the air given to 3,14. When the setting is completed, the operator inputs a start instruction using the keyboard 36. The mechanical section of FIG. 1 is controlled according to the flow chart of the operation shown in FIG. 4 and various calculations are performed by the control section of FIG. 2 based on the measurement data.

Close the solenoid valve SV _3, SV _4, SV ₇ in step S _1, is open to the atmosphere opens the SV _5, SV _6. At step S ₂ , the solenoid valves SV ₁ and SV ₂ are opened and the tanks 13 and 14 are filled with air having the set pressure. In step S ₃ , the T ₁ timer set at a predetermined address in the RAM 42 is started and it is determined whether the time T ₁ has elapsed. If T ₁ is passed the pressure in the tank 13, 14 solenoid valves _{SV 1, SV 2, SV 5} , SV 6 closed in step S ₄ is judged to have reached the equilibrium, Step S ₅
Open solenoid valves SV ₃ and SV ₄ with. In step S ₆ , the T ₂ timer set in the predetermined address of the RAM 42 is started and it is determined whether the time T ₂ has elapsed. When T ₂ has elapsed, it is determined that the pressures of the measurement side air system and the reference side air system have reached equilibrium, and in step S ₇ , the differential pressure ΔP is selected by the multiplexer 32 to select the differential pressure detector 19 from the differential pressure detector 19 at that time. Incorporate detection differential pressure ΔP ₁ RAM 42
Is stored at a predetermined address of. Solenoid valves SV ₃ , SV in step S _8
4 is closed and SV ₅ and SV ₆ are vented to open the measurement side and reference side air systems to atmospheric pressure. Start the T ₃ timer set to a predetermined address in RAM42 in step S _9, determines whether elapsed time T _3. Solenoid valve SV ₇ in step S ₁₀ if T ₃ has elapsed
To drive the piston of the volumetric adder 23 and move it by a preset movable distance to obtain a predetermined volume ΔV _s.
Is added to the measurement side air system. Solenoid valve S again in step S ₁₁
Open V ₁ and SV ₂ and pressurize the tanks 13 and 14 to the set pressure. In step S ₁₂ , the T ₁ timer is started and it is determined whether the time T ₁ has elapsed. When T ₁ has elapsed, the tank pressure P _T is selected by the multiplexer 32 in step S ₁₃ and the detected tank pressure P _T at that time is fetched from the pressure detector 22 and stored in a predetermined address of the RAM 42. Close the solenoid valve _{SV 1, SV 2, SV 5} , SV 6 at step S _14, opening the solenoid valve SV _3, SV ₄ in step S _15. Step S ₁₆
Then, restart the T ₂ timer and determine whether the time T ₂ has elapsed. If T ₂ has elapsed, then in step S ₁₇ the multiplexer 3
The differential pressure ΔP is selected by ₂ and the detected differential pressure ΔP ₂ from the differential pressure detector 19 is fetched and stored in a predetermined address of the RAM 42. In step S ₁₈ , the difference ΔP ′ between the differential pressures ΔP ₁ and ΔP ₂ is calculated, and in step S ₁₉ , the detection sensitivity S is calculated from the added volume ΔV _s and the differential pressure change amount ΔP ′. Then the solenoid valve SV ₃ in step S _20, SV ₄
Is closed, solenoid valves SV ₅ and SV ₆ are opened, the air system is opened (vented) to the atmosphere, and solenoid valve SV ₇ is vented. Then step S ₂₁
Then, the T ₃ timer is started again, and if the time T ₃ has elapsed, the indicator 39 is turned on in step S ₂₂ to end the sensitivity measurement. The sensitivity S calculated in step S ₁₉ is stored in the RAM 42 at a predetermined address.

Operation (volume measurement) Next, according to the flow chart shown in FIG.
Volume difference ΔV between reference container 17 and reference container 18 and internal volume of container 17 to be measured
The operation of measuring V _w will be described.

After mounting the container to be measured 17 in the measurement pipe 15, when the operator performs an instruction to start the keyboard solenoid valve in step S ₁
Close SV ₃ and SV ₄ and open SV ₅ and SV ₆ . Solenoid valve SV in step S _2
1 , SV ₂ is opened, and the tanks 13 and 14 are filled with the air having the set pressure. In step S ₃ , the T ₁ timer set in the RAM 42 at a predetermined address is started to determine whether the time T ₁ has elapsed. If T ₁ has elapsed, in step S ₄ the tank pressure P ′
Measure _T. In Step S ₅ in sensitivity measuring step RAM4
The tank pressure P _T and the sensitivity S stored in 2 are read out, and the corrected sensitivity S ′ is calculated by the equation (14). Solenoid valve SV in step S _6
1 , SV ₂ , SV ₅ and SV ₆ are closed, and solenoid valves SV ₃ and SV ₄ are opened in step S ₇ . Then start the T ₂ timer set to a predetermined address in RAM42 in step S _8, determines whether the elapsed time T _2.
When T ₂ has elapsed, the pressure difference ΔP ₁ between the measurement side and the reference side air system is taken into the measurement RAM 42 in step S ₉ . RA in the step S ₁₀
Start of T ₄ timer set to a predetermined address of the M42 time T ₄
Is determined. Step if T ₄ has passed
At S ₁₁ , the differential pressure ΔP ₂ between the _two air systems is measured again and taken into RAM 42. In step ₁₂ , the measured differential pressures ΔP ₁ and ΔP ₂ and the timer times T ₂ and T ₄ are read from the RAM 42, that is, (t ₁ −t ₀ ) and (t
₂₋ t ₁ ) is read and the corrected differential pressure ΔP ₀ is calculated by the equation (12). In step S ₁₃ , the correction sensitivity S ′ is read from the RAM 42 and the corrected volume difference ΔV of the measured container 17 with respect to the reference container 18 is calculated by the equation (9). Next, the volume difference ΔV is displayed on the display 37 in step S ₁₄ , and the solenoid valve S is displayed in step S _15.
Close V ₃ and SV _4, and open solenoid valves SV ₅ and SV ₆ . T _{3 in} step S ₁₆
If you start the timer, has elapsed time T ₃ step S ₁₇
Then, the indicator 39 is turned over and the measurement is completed. If necessary steps S ₁₃ and wherein the volume V _w of the container to be measured 17 between the S ₁₄ (1
The step S ′ ₁₃ calculated by 0) may be provided as shown by the dotted line.

As described above, when the type of the container 17 to be measured, that is, its volume is changed, by adjusting the volume adjuster 24 without replacing the reference container, a reference container having a volume substantially equal to that of the new type of device 17 to be measured. It is the same as installing 18. Therefore, it is not always necessary to prepare as many reference containers as the number of types of containers to be measured, and by providing the volume adjuster 24, it is possible to reduce the number of reference containers that must be prepared. In this case, the volume change ΔV _(c) of the container adjuster 24, which has been moved and adjusted before the sensitivity measurement shown in FIG. 4, needs to be held as it is during the volume measurement shown in FIG. Therefore the volume difference determined in step S ₁₃ of FIG. 5, if the volume of the reference chamber 18 using the V _'m, the equivalent reference volume V _m =
It represents the volume difference with respect to (V ' _m + ΔV _(c) ), and the equation (10) is transformed as follows.

V _w − (V ′ _m + ΔV _(c) ) = ΔV (15) Therefore, when obtaining the volume of the container 17 to be measured, in step S ′ ₁₃ of FIG. 5, instead of V _m , (V ′ _m + ΔV _{( c)} ) must be used for calculation. Of course, when the volume adjuster 24 is attached to the measurement side air system, (V _w + ΔV _(c) ) may be used instead of V _{w in} the equation (10).

In order to perform the measurement for a large number of containers, first, the detection sensitivity S shown in the flowchart of FIG. 4 is obtained, and thereafter, the measurement shown in FIG. 5 may be executed for each container to be measured. Of course, if the initial tank pressure is properly set to P _T for each container to be measured, steps S ₄ and S ₅ in FIG. ₅ may be omitted, and the sensitivity S not corrected in step S ₁₃ may be used.

What is defined by the equation (1) is always the volume difference between the measurement side air system and the reference side air system. Therefore, the volume adder 23 may be attached to the reference side air system instead of the measurement side. Similarly, the volume adjuster 24 may be attached to the measurement side air system instead of the reference side. Further, the volume adder 23 and the volume adjuster 24 may be provided on the same side. It is preferable that the volume adjuster 24 can be adjusted to increase or decrease the volume from the neutral point.

The proportionality constant K = V _T (V _T + V _M ) ² in the equation (6) has a maximum K when V _T = V _M is selected for a given V _M. That is, if the if of each container to be measured is deposited about the same size, it is possible to obtain an optimum sensitivity by designing the device to select the volume of the pre-tanks 13 and 14 so that the V _T V _M.

As described above, the present invention uses gas, and by measuring the differential pressure between the pressure in the measured container and the pressure in the reference container by the differential pressure detector, It is designed to measure the volume difference of the measured container with respect to the reference container, does not require large-scale equipment such as when using water, and by always measuring the volume relative to the reference volume. , Which enables highly accurate measurement.

Therefore, it is possible to perform a measurement requiring extremely high accuracy, such as a variation measurement of the volumes of a large number of containers having the same specifications, and it is suitable for volume measurement in a production line, for example.

[Brief description of drawings]

FIG. 1 is a diagram showing a mechanical portion of the volume measuring device, FIG. 2 is a diagram showing a control portion of the volume measuring device, FIG. 3 is a diagram showing an output change of the differential pressure detector with respect to time, and FIG. 4 is a sensitivity. FIG. 5 is a flowchart showing the measuring operation, and FIG. 5 is a flowchart showing the volume measuring operation. 11: Compressed air source, 12: Pressure reducing valve, 13, 14: Tank, 15: Measurement side piping, 16: Reference side piping, 17: Measured container, 18: Reference container, 1
9: Differential pressure detector, 21: Pressure gauge, 22: Pressure detector, 23: Volume adder, 24: Volume adjuster, 35: Meter type voltmeter, SV _{1 to} SV ₆ :
Two-way solenoid valve, SV ₇ : Three-way solenoid valve.

Claims (4)

[Claims] 1. A volume adjusting means, which is attached to either one of the measured container side and the reference container side and which substantially balances the measured container side volume and the reference container side volume, and B has the same volume. , A pair of tanks that are filled with gases of equal pressure and supply the gases to the container to be measured and the reference container respectively, and C to a known volume change on either the container to be measured side or the reference container side. Means for giving, D means for measuring the differential pressure between the pressure in the measured container and the pressure in the reference container, E, the amount of change in the differential pressure with and without the volume change, A means for calculating a ratio of a change in differential pressure to a change in volume, which represents detection sensitivity, from the given volume change amount; and a means for calculating a volume difference of the measured container with respect to the reference container from the differential pressure and the detection sensitivity. And is equipped with Product measurement device. 2. Means for measuring the initial pressure of said tank,
2. The volume according to claim 1, further comprising means for correcting the detection sensitivity from the initial pressure of the tank given when the detection sensitivity is obtained and the initial pressure of the tank given when the volume difference is obtained. measuring device. 3. The volume according to claim 1, further comprising means for calibrating a differential pressure used for calculating the volume difference from two differential pressures measured at a predetermined time by the differential pressure measuring means. measuring device. 4. A sensitivity measuring container and a reference container are connected and connected to a pair of tanks having an equal volume filled with gas of an equal pressure, and the sensitivity measuring container internal pressure and the reference container internal pressure after the connection are established. Measuring the pressure difference between the sensitivity measurement container and the reference container with or without a known volume change, and with the given volume change amount, the measurement Calculating the ratio of the change in differential pressure to the change in volume, which represents the detection sensitivity, from the two differential pressures, and connecting the measured container and the reference container to the pair of tanks filled with gas of equal pressure, respectively, and connecting them. A step, a step of measuring a differential pressure between the internal pressure of the measured container and a reference internal pressure after the conduction, and the measured differential pressure and the detection sensitivity with respect to the reference container And a step of calculating the volume difference of the container to be measured.