JPH0219720A - Method and device for measuring volume - Google Patents

Abstract

PURPOSE:To accurately measure the volume of the inside of a tank by providing a division unit for removing an error caused by external impact. CONSTITUTION:A tank 31 for compensation is connected to a main tank 30 through a connection pipe 32 and a vent 35 having a small diameter penetrates through the upper part of the tank 30. A volume changing means 33 is provided on the upper part of the tank 31 and the volume of the tank 31 can be changed with the action of said means 33. A gauge pressure sensor 34 for detecting the pressure of the tank 31 is also provided. The tanks are made to communicate through a valve 10 and the pressure in the tank, where the means 33 is provided, out of the tanks 30 and 31, one of which is changed in terms of volume by the means 33 is detected by the sensor 34 every time the valve 10 is closed and opened. The detected values are divided by each other and the volume of a substance to be measured which is housed in the tank 30 or the 31 is calculated based on the value obtained by division. Therefore, the error caused by the external impact which works to the tank can be removed.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to liquids, powders, granules,
The present invention relates to a volume measuring method and apparatus for measuring the volume of an irregularly shaped object, etc.

[Prior Art] Conventional volume measuring devices of this type are shown in FIGS. 8 to 12.
There is something like the one shown in the figure. This conventional example will be specifically described below.

FIG. 8 shows the initial state at the start of liquid level measurement, and FIG. 9 shows the state during the process of measuring the liquid level, in which the piston (volume change means) 7 is moved to the cylinder (volume change amount) 8.
This shows the state when the object is moved to the deepest part, that is, when it is moved by the maximum stroke.

In FIG. 8, the volume of the tank 3 is vT, the volume of its hollow portion, that is, the portion not filled with liquid 4, is v2, and the volume corresponding to the maximum volume change of the cylinder 8 is V. ((vl
, V2), the volume of the correction chamber 9 is Vl, and the pressure inside the tank 3 is P. Assuming that the door is closed and the valve 10 is released, P is determined based on Poisson's law.
o (V2 + V6 + V1) γ=nRT.

holds true. In addition, n is the number of moles of gas, R is the gas constant,
To represents the absolute temperature of the gas, and γ represents the ratio of specific heat at constant pressure to specific heat at constant volume.

Here, when the piston 7 is moved to the maximum stroke while maintaining heat insulation, as shown in FIG. = 0, and the pressure inside tank 3 increases by ΔPO, (po +Δp,) (V2 +Vl)
γ==nRT.

holds true. From this, PO(V2+ vO+ Vl) γ=(po+Δpo
) (V2÷vl)γ...(1) Equation (1) becomes approximately, and the volume V of the hollow part of the tank 3 becomes.

Next, when the valve 10 is closed in FIGS. 8 and 9, the ventilation between the correction chamber 9 and the tank 3 is completely cut off, and as described above, in FIG. 8, Po (vo +V+) γ= n RT
.

holds true, and in FIG. 9, V. ;0, and the pressure inside the tank 3 increases by ΔPo', so Cpo + ΔPo')■+ γ=nRT.

holds true. As a result, Pa (Vo+V+) γ=(P0+ΔPa')V+
γ - (3) Equation (3) approximately becomes. Here, the volume V corresponds to the maximum volume change amount of the cylinder 8. and the volume vl of the correction chamber 9 are known, and ΔPo
Since ' can be measured, the value of γP0 can be determined. By this, tank 3 in equation (2)
The volume v2 of the cavity can be calculated, and the volume vL of the liquid 4 can be found by Vo-V.

Note that 3a in FIGS. 8 and 9 is a pipe that supplies liquid 4 such as gasoline to the engine.

Next, the structure of a specific example of an apparatus based on the principle of the invention explained above will be explained with reference to FIGS. 1O and 11. In FIG. 10, parts having the same configuration as those in FIG. 8 are designated by the same reference numerals, and their explanations will be omitted.

A piston 7 is made of a disk-shaped permanent magnet having magnetic poles on its circumferential surface, and a magnetic fluid 7a is attracted to its circumferential surface.
It closes the gap with the cylinder 8, which will be described later, to prevent ventilation and reduce the friction when the piston 7 slides inside the cylinder 8. Incidentally, ventilation may be prevented by attaching an O-ring to the circumferential surface of the piston 7. 8 is a cylinder whose one end opening 8a communicates with the correction chamber 9 and the other end is open. 9 is the correction chamber, its volume v1
is set sufficiently small with respect to the total volume of the tank 3 (7 cylinders), and the maximum volume change amount of the cylinder 8, that is, the maximum volume V that changes due to the sliding movement of the piston 7. , the internal pressure changes sinusoidally with one reciprocation of the piston 7, for example.
The correction chamber 9 is connected near the opening edge of the liquid inlet 5 of the tank 3 via the electromagnetic valve 10 and the first vibrator 11 in series, and the correction chamber 9 is connected near the opening edge of the liquid inlet 5 of the tank 3 to is set so that it can flow between the tank 3 and the correction chamber 9. Note that a part of the first vibrator 11 between the liquid injection port 5 and the electromagnetic valve 10 is positioned higher than the opening edge of the liquid injection port, so that the liquid 4 is injected up to the opening edge of the liquid injection port 5. Also, the liquid 4 is set so as not to flow into the correction chamber 9. 12 is a pressure sensor;
A strain plate 12c that partitions the reference pressure chamber 12a, a detection pressure chamber 12b1, and both pressure chambers 12a and 12b, and that distorts in proportion to the difference in pressure between the two pressure chambers, and a strain gauge attached to the strain plate. The reference pressure chamber 12a is connected to the first vibe 11 in series with the cavity chamber 13 and the second vibe 14 of the fine tube, and the cavity chamber 13 and the second vibe 14 are connected to the pressure sensor body 12d. tank 3
It absorbs internal pressure fluctuations and forms a pneumatic filter.

Further, the detection pressure chamber 12b is communicated with the correction chamber 9, and the pressure sensor main body 12d is connected to both pressure chambers 12a, which are received by the strain plate 12c.
, 12b is detected and converted into an electrical signal. 15
is a circular plate, provided with a through hole 15a, and connected to one end of a crank 15b for causing the piston 7 to reciprocate and linearly move. Further, the disc 15 is connected to a rotating shaft of a motor 16, which will be described later, via a reduction gear (not shown).

Reference numeral 17 denotes an optical sensor, which is provided so as to face the through hole 15a at the maximum retracted position of the piston 7.
The through hole 15a is detected. Reference numeral 18 denotes a motor drive control circuit which receives a signal for rotating the motor 16 from an arithmetic processing circuit 21 (described later) immediately after power is turned on, and which controls the optical sensor 1.
A signal for aligning the through hole 15a of the disc 15 with the position 7 is supplied to the motor 16. Also, the motor drive control circuit 18
receives a signal different from the above signal from an arithmetic processing circuit 21, which will be described later, and drives the motor 16 at a constant angular velocity ω. A drive signal for rotationally driving the motor 16 is supplied to the motor 16. 19 is a band-pass filter, and the angular velocity ω of the motor 16; It is set to extract and output only the frequency components corresponding to . , 20 is an amplitude detection circuit which receives the output of the bandpass filter 19 and detects its peak value. 21 is an arithmetic processing circuit, CPU (CENTRAL
PROCESSORtlNIT), ROM (READ
ONl, Y MEMORY), etc., and calculates the liquid level in the tank 3 by manually inputting the output of the amplitude detection circuit 20 and performing the following arithmetic processing, and supplies the calculation result to the display section 22. and display it.

Next, the operation of the arithmetic processing circuit 21 will be explained based on the flowchart shown in FIG.

In FIG. 12, when the power is turned on, the process proceeds from a start step 100 to an initial setting step 101, where the CPt1 and the like constituting the arithmetic processing circuit 21 are initialized, and after a predetermined period of time has elapsed, the valve is closed. In the signal output start step 102, a signal for closing the valve 10 is supplied from the arithmetic processing circuit 21 to the valve 10 via a drive circuit (not shown). Next, coefficient estimation step 10
3, the coefficient TPO value in equation (4) is estimated by reciprocating the piston 7 multiple times. That is, the volume V of the correction chamber 9 stored in the ROM, the volume v0 corresponding to the maximum volume change of the cylinder 8, and the pressure change width ΔP0 in the correction chamber 9 measured by the pressure sensor 12 (of the piston 7). γP0=
Calculate based on ΔP0°V I/V o. After the calculation, the process proceeds to step 104 for stopping the output of the valve closing signal, in which the supply of the valve closing signal to the valve 10 is stopped in order to open the valve 10, and the process proceeds to step 105 for calculating the next tank internal cavity volume. By reciprocating the piston 7 a greater number of times than the number of reciprocating movements of the piston 7 in the coefficient estimation step 103, in step 105, the coefficient γP0. Volume V corresponding to the maximum volume change amount of cylinder 8 stored in ROM. ,
The volume ■. Similarly, the volume ■1 of the correction chamber 9 stored in the ROM and the pressure ΔP0 detected by the pressure sensor 12
(The average value of the pressure change width of the plurality of reciprocating movements of the piston 7) is calculated, and the volume v2 of the hollow part in the tank 3 is calculated, and the process proceeds to the next liquid level calculation step 106, which is calculated in the previous step +05. The volume v2 of the hollow part inside the tank 3 is RO
The volume vL of the liquid 4 is calculated by subtracting it from the total volume (1) of the tank 3 stored in M. The process further proceeds to the next liquid level signal generation step 107, in which a signal for displaying the liquid level on the display section 22 is supplied from the arithmetic processing circuit 21, and then a step to start outputting the valve closing signal is performed. Return to 102. After that, the above operation is repeated periodically or non-periodically. Note that the tank internal cavity volume calculation step 105 and the liquid level calculation step 10
A cancel step (not shown) is provided between the tank 3 and the tank 3 when the volume of the hollow portion in the tank 3 changes significantly.

[Operation] Next, the operation of the above configuration will be explained. When the power is turned on, the through hole 15a is connected from the optical sensor 17 to the motor drive control circuit 18.
A signal for aligning the position of the optical sensor 17 with the position of the optical sensor 17 is supplied, and the motor 16 is rotated to align the through hole 15a of the disc 15 with the position of the optical sensor 17. Note that this operation is completed within a predetermined time immediately after power is turned on. Thereafter, the valve closing signal is supplied from the arithmetic processing circuit 21 to the valve 10 to close the valve 10, and furthermore, the arithmetic processing circuit 21 sends the motor drive control circuit 18 to the motor 1.
A signal instructing the start of multiple rotations of 6 is supplied. When this signal is supplied, the motor drive control circuit 18 drives the motor 16 at a constant angular velocity ω. The disc 15 is connected to the rotating shaft of the motor 16 and is rotated in one direction by a specified number of rotations.
As the piston 7 is rotated, the piston 7 reciprocates within the cylinder 8 via the crank 15b, and air in a volume 1 corresponding to the maximum volume change of the cylinder 8 is sent into the correction chamber 9. When the pressure inside the correction chamber 9 changes in a sinusoidal manner, the pressure in the pressure chamber 12b detected by the pressure sensor 12 changes in a sinusoidal manner as the pressure in the correction chamber 9 is transmitted. The difference between the internal pressure and the equal pressure in the reference pressure chamber 12a is detected by the pressure sensor body 12c and converted into a sinusoidal electrical signal. The signal is supplied to an amplitude detection circuit 20 via a bandpass filter 19, and its peak value is detected. The detected peak values are supplied to the arithmetic processing circuit 21 and averaged to calculate the coefficient γPO.
It is stored in a register or the like within the CPU. Thereafter, the supply of the valve close signal from the arithmetic processing circuit 21 to the valve 10 is stopped, the valve 10 is opened, and the motor 16 is rotated more times than when calculating the coefficient γPG, so that the equation (2) ) is performed, the volume of the liquid 4 in the tank 3 is calculated, and the calculation result is displayed on the display unit 22. Thereafter, the above operation is repeated, and the valve 10
Each time the coefficient γP0 is closed, the coefficient γP0 is updated and stored, and a new liquid level is calculated again.

[Problems to be Solved by the Invention] However, in such a conventional volume measuring device, the above-mentioned signal processing circuit does not control the volume change mechanism 7 in the calculation step 105 of the tank internal cavity volume in the arithmetic processing circuit 21. When pressure is applied by the pressure, if errors due to external shocks such as heat, external force, and vibration are superimposed, the volume will be calculated including the errors. As a result, there was a problem in that the reliability of the measured values was lowered.

[Means for Solving the Problems] The present invention has been made by focusing on the above-mentioned conventional problems, and improves the reliability of measured values by providing a divider to remove errors caused by external shocks. It is an object of the present invention to provide a volume measurement method and device that can improve performance.

[Example] Examples of the present invention will be described in detail below with reference to FIGS. 1 to 7.

First, the principle will be explained with reference to Figures 1 to 6.
30 is an irregularly shaped main tank that stores, for example, liquid, powder □, fluid, and irregularly shaped objects, and this main tank 3
0 is connected to a correction tank 31 via a connecting vibrator 32. Further, a small diameter ventilation hole 35 is bored in the upper part of the irregularly shaped main tank 30. A volume changing means (mechanism) 33 such as a piston, a bellows, a diaphragm, etc. is provided in the upper part of the correction tank 31,
Due to the operation of this volume change mechanism 33, the correction tank 31
It is now possible to change the volume inside.

In addition, in FIG. 5, a gauge pressure sensor 34 for detecting the internal pressure within the correction tank 31 is provided.

Further, the ventilation holes 35 may not be provided by being drilled, but may be holes formed over time.

The configuration of this embodiment has been described above, and the measurement principle based on the configuration will be explained next.

Measurement principle (1) Consider a connected tank system as shown in Figure 1. It is composed of two types of tanks with volumes V, V2. Tank 31. ．． 30 is connected by a vibrator 32 with a flow resistance r1, and a vent hole 35 of the tank 30 has a flow resistance r2. Let γ be the specific heat ratio of the gases in both tanks 30 and 31, R be the gas constant, and τ be the thermal time constant of the tank 31. A volume change mechanism 33 using a piston, diaphragm, bellows, etc. is attached to the tank 31, and the amount of volume change actually generated by this volume change mechanism 33 is expressed as v(t,
).

If the tank 30.31 is a rigid body, the tank 30.31 will not be distorted when the tank is pressurized and depressurized, so the amount of volume change V of the piston, diaphragm, bellows, etc. (1) and the volume change amount v(t,) that actually occurs are equal. If the tank 30 is flexible, the tank 30 will be distorted when the tank is pressurized and depressurized. (1) becomes smaller than v (t).

When v(t)=O, the absolute pressure, temperature, and number of moles of the gas in tank 31 are po, T1, nl, and tank 3, respectively.
Let PO, T2, and n2 be the gases in 0, respectively. If the measurement environment does not change significantly, gas circulates inside and outside the tank 3130 through the vent hole 35, so the absolute pressure p
0 is equal to the outside air pressure, and its change is very slow and changes equal to the outside air pressure.

When v (t)≠0, the pressure, temperature, and number of moles also change depending on the situation of the volume change mechanism 33, and in the tank 31, the pressure is p0+Δp+(t) and the temperature is T1+ΔTl(t).

The number of moles changes as nl-Δn+z(t).

In the tank 30, The pressure is p0+Δpz(t).

The temperature is T2 + ΔT 2 (t).

The number of moles changes as n2+Δr++2(t)−Δn2(t).

Δn+2(t) is the number of moles of air flowing from the tank 31 to the tank 30, and Δn2(t) is the number of moles of air flowing from the tank 30 to the vent hole 35.
is the number of moles of air that leaks to the outside through the

We now make the following assumptions about this system.

1) The gas in the tank is an ideal gas.

2) v(t) < (V+, V2) 3) The heat capacity of the tank 30 is large, and the pressure change Δpz(t
) The temperature change inside the tank due to the change in volume ff1V(t)
It is very slow compared to the speed of change and can be ignored.

4) The rate of change of the volume change amount v (t) is such that the pressure that changes accordingly is the same throughout the tank 30.31.

5) Even if an object to be measured is placed in the tank 30, the object does not create two or more closed gas spaces, that is, a hollow portion, in the tank 30.

The above assumptions do not pose any significant constraints.

Δpt(t), ΔP2(
t), ΔT+(t), 6-cho2(t), Δn+2(t)Δ
The change in nz(t) is originally expressed by a nonlinear equation, but
According to assumption 2), its size is p. , T1, T3 s n
It is very small with respect to l and n2, so it can be approximated by a linear equation. In a static state, the relationship between pressure, temperature, and number of moles is expressed by the following algebraic equation%. Also, from assumptions 1), 3), 4), and 5), in a dynamic state, the pressure of the gas in the tank 30.31, The relationship between temperature and the number of moles is expressed by the following linear ordinary differential equation.

(lb) (ld) This equation was experimentally determined using an aluminum pipe with a length of 50 to 650 [ml11] and a diameter d of 2.0 to 9.0 [mm].

Further, the volume change v(t) is expressed as follows.

v (t) = VO (t) - ΔV (t)
(lh) ΔV is a tank-specific constant determined from the material, shape, volume, etc. of the tank, and Δv(t) is the volume due to expansion and contraction of the tank due to changes in the volume change amount vo(t) of the volume change mechanism 33. It is the amount of change.

Applying Laplace transform to equations (1a) to (li), human power v
The transfer function from (t) to the output Δp+(t) is determined as follows.

ΔT+ (0) = 0
(If) Flow resistance r, in the above equation "h"2
is determined from the length l and diameter d of the vibrator 32 as shown in the following equation.

becomes. Coefficient r2V2/R'h + rlV2/RT2
1 r, t/, /RT.

is the time constant of pressure change. For example r2V2/R12
is the time constant of pressure decay when the gas at the absolute temperature T2 in the hollow portion of the tank 30 flows out of the tank 30 through the vent hole 35 with the flow resistance r2. Correction coefficient ak2(s,
r+, r2. v+, va) varies depending on the volume V of the main tank 30, but the relative ka (S,
In the frequency characteristics of r+, rz, Vt, Vt),
Appropriate frequency, e.g. 4 x 10-' to 10 in section A
-'') By selecting the frequency of Iz, it can be approximately regarded as a constant.

j 1 <<< j 2 (x is the flow resistance of the air vent 35), and the thermal time constant τ and r, (V, +Mi
If nV, )/RT, have similar values, the following angular frequencies exist.

Under this condition, the correction coefficient is 2 (s, r+ +'2+
VI +V2) is approximated as follows.

l'2 (1(Ll +rl+r2+V++V2)
l ~1fk2 (iω+rl+r2+Vl+V2)
= O(2d) Therefore, when the condition of equation (2c) is satisfied, the transfer function from the human power v (t) to the output Δp+(t) is γpo/(Vl″V2+ΔV).

Note that the volume change mechanism 33 has an angular frequency ω. When driven in a sinusoidal manner, it is considered to be equivalent to a state in which is occluded.

That is, That's fine.

(2) Next, consider a single tank system as shown in Figure 3. This corresponds to a case in which the cross-sectional area of the vibrator 32 that connects the tanks 31 and 30 in FIG. From this, from v (t) in Fig. 3, Δp2
The transfer function up to (t) is shown in equation (2a) & r1→0,
T2 = T1. Δpz=Ap+, V, =V, +V
2, which is as follows.

(2f) here, (2g) becomes. Consider the following angular frequency ω.

For example, in the frequency characteristics of Fig. 4, 10-3H shown in A
By setting the frequency to z or higher, the correction coefficient becomes (i
ω, r2. V3') is approximated as follows.

k, (iω+'2+v3°)+41°l kl (iω+r2+V3°)~O(2i) At this time, the transfer function becomes γpo/(Vz°+ΔV).

Next, the above principle will be explained based on a specific example of a rigid tank shown in FIG.

In FIG. 5, the angular frequency ω is such that the volume changing means 33 can ignore the flow resistance r1 of the vibrator 32 having the valve 10. , for example, in a sinusoidal manner at 1O-3Hz, that is, ■. sinω. It is driven slowly and valve 1
0 is alternately closed and opened each time a clock pulse is supplied from the clock pulse generator 45.

As a result, at a certain point in time, only the volume of the correction tank 31 is changed, and at the next point in time, the main tank 30 and the correction tank 31 are regarded as one tank, and the volume thereof is changed.

The pressure fluctuation accompanying the volume change is detected by the gauge type pressure sensor 34.
angular frequency ω whose center frequency is the same as that of the volume changing means 33. and its angular frequency ω. is supplied to a bandpass filter 36 having the same bandwidth as the range of angular frequencies including fluctuations in , and is further valved out at a first amplitude detector 38 via a switching circuit 44.
Further, this pressure variation is sampled and held in a sample and hold circuit 42 connected after the first amplitude detector 38.

On the other hand, when the valve 10 is opened, the connection status of the contacts of the switching circuit 44 is switched by the clock pulse from the clock pulse generator 45, and the output of the bandpass filter 36 is transmitted to the second amplitude detection circuit 39. , the main tank 30 and the correction tank 31 are multiplied by V1 by one tank and the amplifier 43 of the next stage, and then supplied from the amplifier 43 to the output device 40 of the sample-and-hold circuit 42, and corrected by the divider 40. The sum of the volume V of the tank 31 and the volume v2 of the hollow part of the main tank 30 is calculated, and then supplied to the bow calculator 41, and the total volume v of the main tank 30 set by the subtracter 41 is calculated. It is subtracted from the sum (VT''VI) of the total volume of the correction tank 31, and the volume of the object to be measured, that is, the liquid, Vt, (・V
T-V2) is obtained.

Note that the clock pulses output from the clock pulse generator 45 are applied to the valve 10, the switching circuit 44, and the sample
It is supplied to the hold circuit 42 to synchronize them.

Next, a specific example of the flexible tank will be explained based on FIG. 6.

In FIG. 6, the angular frequency ω is such that the volume change mechanism 33 can ignore the existence of the flow resistance r1 of the vibrator 32 having the valve 10. , for example, 10-'l(z) in a sinusoidal manner, i.e. As a result, at one point in time, only the volume of the correction tank 31 is changed, and at the next point, the main tank 30 and the correction tank 31 are regarded as one tank, and the volume thereof is changed. .

The pressure fluctuation accompanying the volume change is detected by the gauge type pressure sensor 34.
, and the center frequency is the same angular frequency ω as that of the volume change mechanism 33. and its angular frequency ω. is supplied to a bandpass filter 36 having the same bandwidth as the range of angular frequencies including fluctuations in the switching circuit 4.
4 to the first amplitude detector 38, and this pressure variation is sampled and held in the sample and hold circuit 42.

On the other hand, when the valve 10 is opened, the connection status of the contacts of the switching circuit 44 is switched by the clock pulse from the clock pulse generator 45, so that the output of the bandpass filter 36 is transferred to the second amplitude detection circuit 39. Then, the main tank 30 and the correction tank 31 are detected as one, multiplied by v1 in the next stage amplifier 43, and supplied to the output device 40 of the sample-and-hold circuit 42. The sum of the volume vI of the main tank 30 and the volume v2 of the hollow part of the main tank 30 is calculated,
After the calculation, the output is supplied to the subtracter 41, and the total volume vT of the main tank 30 set by the subtracter 41, the total volume v1 of the correction tank 31, and the total volume v1 of the main tank 30 due to pressurization are calculated. Sum of expansion △V (V+V, +ΔV)
The volume of the object to be measured in the main tank 30 v
L is required.

Note that the clock pulses output from the clock pulse generator 45 are applied to the valve 10, the switching circuit 44, and the sample
It is supplied to the hold circuit 42 to synchronize them.

In each of the above embodiments of the present invention, the volume of the object to be measured in the tank when the liquid was injected into the tank was measured, and as shown in FIG. Highly accurate volume measurements were made.

[Effects of the Invention] As described above, the present invention provides two tanks, one of which is connected to the first and second tanks through a valve and whose volume is changed by the volume changing means. The fluctuation pressure sensor of the first or second tank internal pressure, whichever is provided with the volume change means, detects each opening and opening of the valve, divides each of the detected values mutually, and calculates the divided value. Since the volume of the object to be measured stored in the first or second tank can be calculated based on the above, errors caused by external shocks such as heat, external force, and vibrations applied to the tank are removed. As a result, the volume inside the tank can be accurately measured.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, and Fig. 2 shows how the coefficient of the transfer function changes when the driving frequency of the volume change mechanism and the volume of the contents in the tank are changed in Fig. 1. Characteristic diagram, Figure 3 is a principle explanatory diagram to explain Figure 1,
FIG. 4 is a characteristic diagram showing a state in which the coefficient of the transfer function changes by 1 when the drive frequency of the volume change mechanism and the volume of the contents in the tank are changed in FIG. 3, and FIG. 6 is a detailed explanatory diagram of another embodiment of the present invention,
FIG. 7 is a graph showing volume measurement values according to the above embodiment, and FIGS. 8 to 12 are explanatory diagrams of conventional examples. 30... Main tank 31... Correction tank 32
...Connection vibrator 33...Volume change mechanism 34...
・Gauge sensor 35...Vent hole 36.37...Band pass filter 38.39...Amplitude detector 40...Divider 41...Subtractor 42...
Sample/hold circuit 43...Amplifier 44...Switching circuit 45...
・Clock pulse generator Fig. Volume measurement value (Q) Cavity partial volume Vy (11) Fig. Vo (tl Fig.

Claims (1)

[Scope of Claims] 1. Among first and second tanks that are communicated via a valve and whose volume is changed by the volume changing means, the first tank is provided with the volume changing means. Alternatively, a pressure sensor detects fluctuations in the pressure inside the second tank each time the valve is closed and opened, divides each of the detected values by each of the detected values, and adjusts the pressure in the first or second tank based on the divided value. A volume measurement method that calculates the volume of an object to be measured stored inside. 2. A first tank, a second tank that stores an object to be measured, a valve that communicates the first and second tanks, and a volume changing means that changes the volume of the first or second tank. , a pressure sensor for detecting a change in the pressure inside the first or second tank provided with the volume change means, and a first pressure sensor for detecting an amplitude value of a detected value from the pressure sensor when the valve is closed. an amplitude detector, a storage means for storing the output of the first amplitude detector, a second amplitude detector for detecting the amplitude value of the detected value from the pressure sensor when the valve is opened; a divider for dividing the value stored in the storage means by the output of the second amplitude detector, and the volume of the object to be measured stored in the second tank based on the output of the divider. A volume measuring device characterized by calculating.