JP2561759Y2 - Volume measurement device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume measuring device for measuring the volume of liquid, powder, granules, irregularly shaped objects, etc., stored in a tank.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional volume measuring apparatus, and FIG. 3 is a longitudinal sectional view showing a main tank.

[0003] The present applicant has proposed a volume measurement method capable of measuring the amount of stored material (filled) in, for example, a resin tank by detecting a pressure change in the tank. A number of applications for related equipment have been filed.

FIG. 2 shows a volume measuring apparatus of this type of the prior application, in which 3 is a main tank formed of a synthetic resin. The main tank 3 has a liquid inlet 5
Can supply a liquid 4 such as gasoline. Reference numeral 6 denotes a lid attached to the liquid inlet 5, and reference numeral 3a denotes a liquid guide tube for introducing the liquid 4 into, for example, an engine.

[0005] Reference numeral 7 denotes a piston, which is formed of a disk-shaped permanent magnet having magnetic poles on its peripheral surface and has a magnetic fluid 7a on its peripheral surface.
Is sucked to close a gap with the cylinder 8, which will be described later, to prevent ventilation, and to reduce friction when the piston 7 slides in the cylinder 8. The peripheral surface of the piston 7 has O
Ventilation may be prevented by attaching a ring. One end opening 8a of the cylinder 8 communicates with the correction tank 9 and has the other end opened. The volume V ₁ of the correction tank 9 is set to be sufficiently smaller than the total volume V _T of the main tank 3 and the maximum volume change amount of the cylinder 8, that is, the maximum volume V ₀ changed by sliding of the piston 7. In contrast, for example, the volume is set to be ten times as large, and the internal pressure change changes sinusoidally by one reciprocation of the piston 7 (this is due to the constant speed rotation of the motor 16 described later). The correction tank 9 includes an electromagnetic valve 10
And the main tank 3 via the first pipe 11 in series.
Is set near the opening edge of the liquid inlet 5 so that gas can flow between the inside of the tank 3 and the correction tank 9. Note that a portion of the first pipe 11 between the liquid inlet 5 and the electromagnetic valve 10 is positioned higher than the opening edge of the liquid inlet, and the liquid 4 is injected to the opening edge of the liquid inlet 5. Even so, the liquid 4 is set so as not to flow into the correction tank 9.

A pressure sensor 12 partitions a reference pressure chamber, a detection pressure chamber, and both pressure chambers (not shown), and distorts in proportion to the pressure difference between the two pressure chambers. The reference pressure chamber of the first pipe 1 is connected in series with the cavity 13 and the second pipe 14 of the fine tube.
1 and its cavity 13 and second pipe 14
Absorbs pressure fluctuations in the tank 3 and constitutes a pneumatic filter. Further, the detected pressure chamber is communicated with the correction tank 9, and the pressure sensor main body detects a pressure difference between the two pressure chambers received by the strain plate and converts it into an electric signal. Reference numeral 15 denotes a disc having a through hole 15a and one end of a crank 15b for linearly reciprocating the piston 7 connected thereto. The disk 15 is connected to a rotating shaft of a motor 16 to 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 a position where the piston 7 is retracted to the maximum, and detects the through hole 15a of the disk 15. Reference numeral 18 denotes a motor drive control circuit which receives a signal for rotating the motor 16 immediately after the power is turned on from an arithmetic processing circuit 21 to be described later, and aligns the through hole 15a of the disk 15 with the position of the optical sensor 17. The signal is supplied to the motor 16. Further, the motor drive control circuit 18 receives a signal different from the above-mentioned signal from an arithmetic processing circuit 21 to be described later, and sets the motor 16 at a constant angular velocity ω.
₀ supplies a drive signal for allowing driving rotation of the motor 16.

Reference numeral 19 denotes a band pass filter, which
Is set so as to extract and output only the frequency component corresponding to the angular velocity of the noise, a noise component generated by the pressure sensor 12, a drift component generated by the pressure sensor 12 in response to a temperature rise in the main tank 3, and the like. Is removed. Reference numeral 20 denotes an amplitude detection circuit which receives the output of the band pass filter 19 and detects the peak value. 21 is an arithmetic processing circuit, C
PU (CENTRALPROCESSOR UNI)
T), a ROM (READ ONLY MEMORY), etc., the output of the amplitude detection circuit 20 is input, and the following arithmetic processing is executed to calculate the liquid level in the tank 3 and display the calculation result on the display unit. 22 to be displayed.

Next, the operation will be described. When the power is turned on, a signal for aligning the through hole 15a with the position of the optical sensor 17 is supplied from the optical sensor 17 to the motor drive control circuit 18, and the motor 16 is rotated to move the disc to the position of the optical sensor 17. The fifteen through holes 15a are aligned. In addition,
This operation is completed within a predetermined time immediately after the power is turned on.

Thereafter, the arithmetic processing circuit 21 sends a signal to the valve 10
Is supplied to the valve 10 so that the valve 10
Is closed, and a signal for instructing the motor 16 to start rotating a plurality of times is supplied from the arithmetic processing circuit 21 to the motor drive control circuit 18.

When the signal is supplied, the motor drive control circuit 18 rotates the motor 16 in one direction at a constant angular velocity and rotates the disk 15 connected to the rotation shaft of the motor 16. Crank 15
b, the piston 7 reciprocates in the cylinder 8, and sends air of a volume V ₁ corresponding to the maximum volume change amount of the cylinder 8 to the correction chamber 9 or sucks air of the correction tank 9, When the pressure in the correction tank 9 is changed in a sine wave shape, the pressure of the detection pressure chamber of the pressure sensor 12 becomes
When the pressure in the correction tank 9 is transmitted, the pressure changes in a sinusoidal manner, and the difference between the internal pressure of the main tank 3 and the pressure in the reference pressure chamber is detected by the pressure sensor main body and converted into a sinusoidal electric signal.

The signal is supplied to an amplitude detection circuit 20 via a band pass filter 19, and the peak value is detected. The detected peak value is supplied to the arithmetic processing circuit 21 and averaged, whereby a coefficient is calculated and stored in a register or the like in the CPU. Thereafter, the arithmetic processing circuit 21
Supply of the valve closing signal to the valve 10 is stopped from
The valve 10 is opened, and the volume of the liquid 4 in the main tank 3 is calculated by rotating the motor 16 more times than when calculating the coefficient, and the calculation result is displayed on the display unit 22. .

Thereafter, the above operation is repeated, and the valve 10
Each time is closed, the coefficient is updated and stored, and the liquid level is newly calculated again.

[0014]

Since the conventional volume measuring device is constructed as described above, its main tank 3
When a large tank with a large capacity is made of resin and made of metal even if it is made of metal, the liquid 4 is shaken when external vibration is applied to the main tank 3 containing a large amount of liquid 4. And the upper wall or the bottom wall of the main tank 3 has a specific frequency, e.g.
It vibrates at a very low frequency of 30 Hz. Therefore, there is a problem that the signal component extracted by the band-pass filter 19, that is, the driving frequency of the piston 7 approaches, and it becomes difficult to extract the signal component.

The present invention has been made to solve the above-described problem, and can increase the resonance frequency (natural frequency) of the main tank 3 due to the swing of the liquid 4 in the main tank 3. Bandpass filter 19
It is an object of the present invention to obtain a volume measuring device capable of facilitating extraction of a signal component at a time.

[0016]

A volume measuring device according to the present invention comprises a main tank having a structure in which a main tank is provided between an upper wall and a lower wall other than a portion corresponding to a node of vibration on a vibration surface formed by the resonance frequency. In addition, an elastic connecting member for always pressing the upper and lower wall surfaces from the inside to the outside is provided.

[0017]

In the volume measuring apparatus according to the present invention, the resonance frequency of the main tank is increased, and it is easy to separate from the frequency of the signal component extracted by the band-pass filter, and the signal processing is easy.

[0018]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 2 is a longitudinal sectional view of a main tank of the volume measuring device according to one embodiment of the present invention. In the figure, 3 is a main tank,
Reference numeral 30 denotes a compression spring that presses the upper wall 31 and the lower wall 32 of the main tank 3 from inside, and 31a and 32a denote the upper wall 31 and the lower wall 3, respectively.
2 is a spring seat for a compression spring formed in FIG. Spring seat 31
The positions of a and 32a are set at positions other than a portion corresponding to a node of vibration in the vibration surface formed by the vibration surface formed by the resonance frequency of the main tank. In addition,
The same parts as those of the conventional device are denoted by the same reference numerals, and description thereof will be omitted.

Next, the operation will be described. The upper wall 31 and the lower wall 32 of the main tank 3 are always pressed from the inside to the outside by the compression spring 30, so that the compression spring 30
The resonance frequency generated in the main tank 3 is shifted to a frequency in a high frequency band by the action of the above, so that the resonance frequency does not approach the frequency of the signal component, the signal component is easily extracted, and the volume detection is performed. Not only can the accuracy be improved, but the intended compression spring 30 can be easily and accurately installed at a predetermined position in the tank 3.

[0020]

As described above, according to the present invention, the upper and lower walls of the vibrating surface formed by the resonance frequency of the main tank other than the portion corresponding to the node of the vibration always move up and down. Since the elastic connecting members that press both ends from the inside are provided, the resonance frequency of the main tank can be increased, and therefore, there is an effect that the signal component can be accurately and easily extracted by the bandpass filter.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main tank of a volume measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional volume measuring device.

FIG. 3 is a longitudinal sectional view showing a main tank of a conventional volume measuring device.

[Explanation of symbols]

 3 Main tank 9 Correction tank 30 Compression spring (elastic connecting member) 31 Upper wall 32 Lower wall

Claims (1)

(57) [Scope of request for utility model registration] 1. A synthetic resin main tank for storing an object to be measured, a correction tank provided in communication with the main tank, and a volume changing means for changing the internal pressure of each of these two tanks at a predetermined frequency. In a volume measuring device comprising: a detecting means for detecting a pressure change in both tanks by the volume changing means, the main tank,
An elastic connecting member that constantly presses the upper and lower walls from the inside between an upper wall and a lower wall other than a portion corresponding to a node of vibration in a vibration surface formed by the resonance frequency. Characteristic volume measurement device.