JP2001215145A - Flowmeter calibration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely calibrate a flowmeter which measures the flow rate of an oil liquid. SOLUTION: The flowmeter calibration system 10 is constituted of a storage tank 12. The calibration system is constituted of an oil-liquid supply line 14 which supplies the oil liquid in the storage tank 12. The calibration system is constituted of a bypass line 16 which is branched from the oil-liquid supply line 14. The calibration system is constituted of a density meter 18 which is attached to the bypass line 16. The calibration system is constituted of a communtation device 20 which distributes the oil liquid flowing into from the oil-liquid supply line 14. The calibration system is constituted of a metering tank 22 which meters the oil liquid supplied from the commutation device 20. The calibration system is constituted of a collection tank 24 for circulation, which stores the oil liquid supplied from the commutation device 20 at a time when a measurement is not performed. The calibration system is constituted of a weight mechanism 26 which is suspended from the metering tank 22. The calibration system is constituted of a reference balance 28 which measures the mass of the oil liquid stored in the metering tank 22. One end of the bypass line 16 is branched so as to be connected to the oil-liquid supply line 14 formed between a first pump 30 and the flowmeter 34, and the other end is opened to the air inside the collection tank 24 for circulation. Weight plates 581 to 58n are remobed one by one so as to correspond to the flow rate of the oil liquid supplied to the metering tank 22 so that a change in a load acting on the reference balance 28 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter calibration system, and more particularly to a flow meter calibration system configured to accurately calibrate a flow meter for measuring a flow rate of an oil liquid.

[0002]

2. Description of the Related Art In order to calibrate a flow meter that has been assembled, a flow meter is installed in the piping of a flow meter calibration system,
The amount of water sent from the pump is actually measured to check the measurement accuracy inherent to the flow meter. In this type of flow meter calibration system, the properties of the fluid, such as light oil and kerosene, are different between water and the oil liquid that is often used as the actual fluid to be measured. When performing calibration,
The flowmeter can be more accurately calibrated by measuring the flow rate of the oil liquid and performing calibration.

In order to calibrate a flow meter for measuring an oil liquid such as light oil or kerosene, the flow meter calibration system measures the flow rate using an oil liquid as a fluid to be measured, and measures the measured flow rate and the measuring tank. It is considered that a measurement error is obtained from a difference in the volume of the oil liquid supplied to the apparatus.

However, since the flow rate and the mass cannot be directly compared, the flow rate (m ³ ) × the density (kg / m ³ ) = the mass (k
It is necessary to perform the operation based on the relational expression of g). Therefore, when calibrating with a measuring tank, the error due to bubbles in the liquid and temperature changes is large, so when calibrating the flow meter using the oil liquid, measure the density of the oil liquid measured with the flow meter,
It is necessary to calibrate the mass and density of the oil liquid supplied to the measuring tank.

However, in the above-described flow meter calibration system, the density of the fuel is measured in the bypass line that bypasses the upstream and downstream of the flow meter as a test meter disposed in the oil liquid supply line. When a configuration is provided so that the density of the oil liquid supplied to the flow meter can be measured by providing a meter,
Because the pressure difference between the inflow side and the outflow side of the bypass line is small,
Insufficient oil liquid is supplied to the density meter. Therefore, it is necessary to secure an oil liquid supply amount to the density meter by providing an orifice in the oil liquid supply pipe downstream of the point where the bypass pipe branches, and increasing the pressure on the inflow side of the bypass pipe.

However, in such a configuration, the temperature of the oil liquid passing through the orifice rises due to fluid resistance, and the density of the oil liquid passing through the flow meter changes, causing a measurement error. There is.

Further, since there are a plurality of flow meters having different diameters as test meters disposed in the oil supply line, the flow rate of the oil differs depending on the type of the flow meter, and the oil flow through the bypass line is different. The flow velocity also varies depending on the size of the flow meter, and there is a problem that a measurement error of the density occurs.

In the flowmeter calibration system as described above, a balance as a mass measuring means for measuring the mass of the measuring tank measures the mass from a state in which the oil liquid is zero to a state in which the oil liquid is full. For example, even after adjusting the zero point of the scale, after a load of 10 tons is applied in the full state, the zero point shifts because the load difference between non-measurement and measurement is large,
There is a problem that the measurement error due to the hysteresis causes the calibration accuracy of the flow meter to be reduced.

[0008] Here, in order to add a comment on hysteresis, for example, when the structure corresponding to a large load measurement is a combination of a lever and a fulcrum, when the fluctuating load is large, the contact portion of each lever fulcrum tends to shift. This is because the load measurement lacks reproducibility. Therefore, an object of the present invention is to provide a flowmeter calibration system that has solved the above-mentioned problems.

[0009]

The present invention has the following features to solve the above-mentioned problems.

According to the first aspect of the present invention, there is provided an oil liquid supply path for supplying an oil liquid in a storage tank, a pump for supplying the oil liquid through the oil liquid supply path, and an oil liquid supply path attached to the oil liquid supply path. A flow meter as a test meter for measuring the oil liquid sent by the pump, a measuring tank to which the oil liquid measured by the flow meter is supplied, and the oil liquid supply upstream of the flow meter. A density meter attached to a bypass pipe branched from a path, and mass measuring means for measuring the mass of the measuring tank, the measured value of the flow meter, the measured value of the mass measuring means, and the density meter The flowmeter calibration system is configured to calibrate the flowmeter by calculating and comparing the measured value with the measurement value of the above, wherein the other end of the bypass pipe is open to the atmosphere.

Therefore, according to the first aspect of the present invention, since the other end of the bypass pipe is open to the atmosphere, it is possible to provide a sufficient pressure in the bypass pipe provided with the density meter without providing an orifice in the oil liquid supply path. The oil liquid can be supplied, and the flowmeter can be calibrated accurately. Also, even when calibrating flowmeters with different sizes, there is no effect of flow rate change due to the orifice of the oil liquid supply path,
Calibrate the flow meter accurately.

Further, according to the present invention, an oil liquid supply path for supplying the oil liquid in the storage tank, a pump for supplying the oil liquid via the oil liquid supply path, and an oil liquid supply path are provided. A flow meter as a test meter that is attached and measures the oil liquid sent by the pump, a measuring tank to which the oil liquid measured by the flow meter is supplied, and the oil liquid upstream of the flow meter A density meter attached to a bypass pipe branched from a supply path, and mass measuring means for measuring the mass of the measuring tank, wherein the measured value of the flow meter, the measured value of the mass measuring means, and the density A flow meter calibration system configured to calibrate the flow meter by calculating and comparing the measured value of the meter with a mass equal to the mass of the maximum amount of oil liquid to be measured, and divided into a plurality. Weight and the divided weights Driving means, which is appropriately mounted on the mass measuring means, or which is appropriately removed, and drives the driving means in accordance with the measurement value or mass measurement value of the flow meter, to increase the amount of oil liquid supplied to the measuring tank. Correspondingly, the control unit controls to remove the divided weights step by step.

Therefore, according to the second aspect of the present invention, the driving means is driven in accordance with the measurement value or the mass measurement value of the flow meter, and the driving means is driven in response to an increase in the amount of oil supply to the measuring tank. Accurately calibrate the flowmeter by reducing the change in load applied to the mass measuring means and reducing the measurement error due to hysteresis when measuring the mass of the weighing tank by removing the weights divided step by step. Can be.

According to a third aspect of the present invention, there is provided an oil liquid supply path for supplying the oil liquid in the storage tank, a pump for supplying the oil liquid via the oil liquid supply path, and an oil liquid supply path. Attached, a flow meter as a test meter for measuring the oil liquid sent by the pump, a measuring tank as a reference meter to which the oil liquid measured by the flow meter is supplied, and an upstream from the flow meter A density meter attached to a bypass pipe branched from the oil liquid supply path, and mass measuring means for measuring the mass of the measuring tank, and a measurement value of the flow meter and a measurement of the mass measuring means. A flow meter calibration system configured to calibrate the flow meter by calculating and comparing a value and a measurement value of the density meter, the system being mounted on the mass measuring means and containing a maximum amount of oil liquid to be measured. Quality of the measuring tank A weight tank for storing a liquid having the same mass as the above, a pump for discharging the liquid stored in the weight tank, and driving the pump in accordance with a measurement value of the flow meter to supply an oil liquid to the measuring tank. And a control unit for controlling the discharge of the liquid stored in the weight tank in response to the increase in the amount.

Therefore, according to the third aspect of the present invention, the pump is driven according to the value measured by the flow meter, and the liquid stored in the weight tank is increased in response to the increase in the amount of oil supplied to the measuring tank. , It is possible to make the discharge flow rate from the weight tank the same as the supply flow rate to the weighing tank, and to minimize the change in load applied to the mass measuring means. Calibration of the flow meter can be accurately performed by reducing measurement errors due to hysteresis.

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

FIG. 1 is a block diagram showing one embodiment of a flow meter calibration system according to the present invention.

As shown in FIG. 1, a flow meter calibration system 10 measures a flow rate using an oil liquid such as kerosene or light oil as a fluid to be measured, and generally includes a storage tank 12 for storing the oil liquid and a storage tank 12 for storing the oil liquid. , An oil liquid supply line 14 for supplying the oil liquid in the storage tank 12, a bypass line 16 branched from the oil liquid supply line 14, and a density meter 1 attached to the bypass line 16.
8, a commutator 20 for distributing the oil liquid flowing from the oil liquid supply pipe 14, a measuring tank 22 for storing the oil liquid supplied from the commutator 20, and a supply from the commutator 20 when measurement is not performed. A circulation recovery tank 24 for storing the collected oil liquid, a weight mechanism 26 suspended from the measuring tank 22, and a reference as a reference device for measuring the mass of the oil liquid stored in the weight mechanism 26 and the measuring tank 22. And a scale 28.

In the oil supply line 14, a first pump 30 for sending the oil in the storage tank 12 from the upstream side, a high-precision flow meter 32 as one of the reference devices, and a test meter as the test meter. A flow meter 34, a flow control valve 36 for adjusting the supply amount of the oil liquid to a predetermined flow rate, and an on-off valve 38 formed of an electromagnetic valve are provided. Here, the high-accuracy flow meter 32 is used as one of the reference devices for calibrating the flow meter 34 as a test meter. And the high precision flow meter 32
Is used a predetermined number of times, an error occurs.

The bypass line 16 has one end connected to the first pump 3.
0 and the oil supply line 1 formed between the flow meter 34
4 and the other end is inserted into the circulation recovery tank 24 and is open to the atmosphere in the circulation recovery tank 24. The bypass pipe 16 is provided with a flow control valve 40 for adjusting the flow rate of the oil liquid supplied to the density meter 18 to a constant flow value.

Since the other end of the bypass pipe 16 is open to the atmosphere in the circulation recovery tank 24, the bypass pipe 1
6 has a sufficient pressure difference between one end and the other end. Therefore, the first
The oil liquid sent from the pump 30 is also sufficiently supplied to the bypass line 16, so that the density measurement of the oil liquid by the density meter 18 can be performed accurately. As a result, it is not necessary to provide an orifice in the oil supply pipe 14, and it is possible to avoid an increase in the temperature of the oil due to fluid resistance.

Further, even when the flowmeters 34 having different diameters are mounted, the flow rate of the oil liquid does not change, so that the flow rate of the oil liquid flowing through the bypass line 16 does not change, and the measurement error of the density accompanying the flow rate change is reduced. Can be prevented. In the flow meter calibration system 10, when the high-precision flow meter 32 is provided, the oil liquid divided at the branch point between the oil liquid supply pipe 14 and the bypass pipe 16 is subjected to the high-precision flow rate. It is desirable that the time Ta until reaching the meter and the time Tb until the oil liquid diverted at the branch point reaches the density meter 18 match.

Therefore, if the distance from the branch point between the oil supply line 14 and the bypass line 16 to the high-precision flow meter and the distance from the branch point to the density meter 18 are significantly different, the bypass line The flow rate is adjusted so that the oil liquid diverted at the branch point reaches the high-precision flow meter and the density meter 18 at almost the same timing by adjusting the valve opening of the flow control valve 40 disposed at 16. Thereby, the high-precision flow meter and the density meter 18
Can measure the flow rate and the density without being affected by a change in the temperature of the oil flowing through the oil supply pipe 14 and the bypass pipe 16.

When the high-precision flow meter 32 is not provided, the flow velocity is adjusted so that the oil liquid diverted at the branch point reaches the flow meter 34 and the density meter 18 at almost the same timing.

The commutator 20 has a drop line 42 connected to the measuring tank 22 and a drop line 44 connected to the collection tank 24, before, during, and after the flow rate measurement. The communication path with the measuring tank 22 or the collection tank 24 is switched according to each mode. That is, the commutator 20 is provided in a branch path between the measuring tank 22 and the recovery tank 24, and oscillates a commutation plate (not shown) provided therein to remove the oil liquid before the flow rate measurement. It operates to guide the oil liquid to the collection tank 24 and to guide the oil liquid to the measuring tank 22 during the flow rate measurement.

A discharge pipe 46 is provided between the measuring tank 22 and the recovery tank 24, and a discharge valve 48 is provided in the discharge pipe 46. After the flow rate measurement is completed and the mass of the measurement tank 22 is measured, the discharge valve 48 is opened to discharge the oil liquid stored in the measurement tank 22 to the collection tank 24. The recovery tank 24 is connected to a reflux line 50 for returning the oil liquid to the storage tank 12. The reflux pipe 50 is provided with a second pump 52 that sends the oil liquid in the recovery tank 24 to the storage tank 12.

The density meter 18, the commutator 20, the weight mechanism 2
6. Reference scale 28, first pump 30, high-precision flow meter, flow meter 34, flow control valve 36, on-off valve 38, flow control valve 4
0, the discharge valve 48, and the second pump 52 are connected to the control unit 54, and are driven and controlled by a command from the control unit 54 as described later.

The measuring tank 22 is provided with a weight mechanism 26 so as to always have a load close to a state where the oil liquid is full.
Is suspended, and as will be described later, a plurality of weights of the weight mechanism 26 are lifted in a stepwise manner so that the reference scale 28 is moved.
Is reduced to eliminate the measurement error due to the hysteresis of the reference scale 28.

Here, the configuration of the weight mechanism 26 will be described.

FIG. 2 is an enlarged perspective view showing the structure of the weight mechanism 26. FIG. 3 is an enlarged front view showing the configuration of the weight mechanism 26. FIG. 4 is an exploded perspective view showing a main part of the weight mechanism.

As shown in FIGS. 2 and 3, the weight mechanism 26 includes a support 56, a plurality of weight plates 58 _{1 to} 58 _n suspended below the support 56, and a plurality of weight plates 58.
_{1 to} 58 _n in a stepwise manner. The support 56 is provided with a mounting plate 56 a on which the measuring tank 22 is mounted and a mounting plate 56 a
And a book leg 65b. Therefore, the reference scale 28 has a weighing tank 22, a support base 56, minute copper plate ₅₈ 1 to 58 _n
Are provided so as to apply the respective loads.

The operating device 60 includes four hydraulic cylinders (driving means) 62 to 65 arranged on both sides of the support base 56 (the hydraulic cylinder 64 is hidden and cannot be seen in FIG. 2). An elevating base 66 supported by each of the piston rods 62a to 65a. The hydraulic cylinders 62 to 65 are supplied with hydraulic oil pressurized by a command from the control unit 54, and are supplied with four piston rods 62a to 65.
a is raised and lowered simultaneously. The elevating base 66 moves up and down step by step by the operation of the elevating base 66 while keeping the horizontal state.

As shown in FIG. 4, a plurality of weight plates 58
For example, _{1 to} 58 _n has a mass of 1 ton per sheet, and _assuming that the capacity that can be stored in the measuring tank 22 is 10 tons, 10 weight plates are stacked. In addition, the plurality of weight plates 58 _{1 to} 58 _n have hemispherical projections 68 on the lower surface side.
Are projected so that they are not in close contact with each other even when they are stacked.

Furthermore, on the lower surface of the mounting plate 56a of the supporting table 56, four posts 71 to 74 for supporting the suspended state the partial copper plate ₅₈ 1 to 58 _n is fixed. The weight plates 58 _{1 to} 58 _n are provided with insertion holes 76 _{1 to} 76 _n through which the columns 71 to 74 are inserted. Insertion holes 76 _1-
76 _n are formed in different sizes, each having a different diameter D _{1 to} D _n , and the inner diameter is reduced stepwise so that the smaller the diameter, the lower the diameter. Therefore, the insertion holes 76 ₁ to 76 ₁
The respective diameters of 76 _n are D ₁ > D ₂ > D ₃ to> D _n .

Each of the columns 71 to 74 has a corresponding one of the insertion holes 76.
₁~ 76_nThe diameter of the step formed to correspond to
Different steps 71₁~ 71_n, 72₁~ 72_n, 73₁~
73 _n, 74₁~ 74_nHaving. And pillars 71-
At the lower end of 74, an insertion hole 76 ₁Larger diameter flange 71a
To 74a. In addition, the flange portions 71a to 74a
Step 71 formed above₁~ 71_n, 72₁~ 72
_n, 73₁~ 73_n, 74₁~ 74_nThe outer diameter of the insertion hole
76₁~ 76_nDiameter D of₁~ D_nSmaller diameter than
And is formed to be larger in diameter than the insertion hole one step higher. Sa
In addition, step 71₁~ 71_n, 72₁~ 72_n, 73₁~
73_n, 74₁~ 74_nThe height dimension of the weight plate 58₁~
58_nIs slightly larger than the thickness dimension of.

The lifting base 66 supported by the piston rods 62a-65a of the hydraulic cylinders 62-65.
Is provided with a through hole 66a having a larger diameter than the flange portions 71a to 74a. Therefore, the elevating base 66 has the flange portions 71a-
When it is located below 74a, the weight plates 58 _1-
58 _n is the flange portion 71a~74a and stepped portions ₇₁ 1 _-71 n strut _{71~74, 72 1 ~72 n, 73} 1 ~73 n, 7
4 ₁ to 74 _n , each weight plate 5
8 _1-58 standard total load of _n via the support base 56 scale 28
Is acting on.

[0036] When the elevating base 66 by upward movement of the piston rod 62a~65a of the hydraulic cylinders 62 to 65 from this state is raised one step, the lifting base 66 is in contact with the weight plate 58 ₁ of the lowest stage, the partial copper plate 58 ₁ lift. Thus, minute copper plate 58 _1, a flange of the column 71 to 74 71
This is the same as the state in which the load is removed from the columns 71 to 74 while being separated upward from the columns a to 74a. Therefore, the reference scale 28
Is in a state _where the masses of the weight plates 58 _{2 to} 58 _n act.

Furthermore, the elevation base 66 is raised one step, the lifting base 66 is brought into contact with the weight plate 58 _2, minute copper 5
Lift the 8 _2. Thus, minute copper 58 ₂ is the same as the state of removing the load from the posts 71 to 74 from the stepped portion ₇₁ 72d ₁ of the strut 71 to 74 spaced upwardly.
Therefore, the reference scale 28 is in a state in which the mass of minute copper plate ₅₈ 3 to 58 _n is applied.

As described above, the weights of the weight plates 58 _{1 to} 58 _n can be changed to a state in which the weight bases 66 are stepped up and removed one by one from the reference scale 28.

Here, the control processing executed by the control unit 54 will be described.

FIG. 5 is a flowchart of a control process executed by the control unit 54. FIG. 6 is a flowchart for explaining a process executed after the process of FIG.

As shown in FIG. 5, when the start switch (not shown) is turned on after the power is turned on in step S11 (hereinafter, "step" is omitted) in step S11 (step S11), the control unit 54 proceeds to step S12. Then, the pump 30 is started, and the on-off valve 38 is opened to send the oil liquid stored in the storage tank 12. When the pump 30 is started, the oil liquid in the storage tank 12 is supplied at a predetermined flow rate to the oil liquid supply line 1.
4 as well as the oil liquid to the bypass line 16 branched from the oil liquid supply line 14 downstream of the pump 30. At this time, since the other end of the oil liquid supply pipe 14 is open to the atmosphere in the circulation recovery tank 24, there is a sufficient pressure difference between one end and the other end of the bypass pipe 16. Therefore, the oil liquid sent from the first pump 30 is supplied to the bypass line 16.
And the density of the oil liquid by the density meter 18 can be accurately measured.

In the next step S13, it is confirmed that the flow rate can be measured by the flow rate pulse from the flow meter 34 attached to the oil liquid supply line 14. In S13,
When the flow rate pulse is not output from the flow meter 34, there is some abnormality.
Return to 11. In this case, the worker checks whether there is any abnormality in the mounting method of the flow meter 34 or whether there is any abnormality in the flow meter 34 itself, and starts over from the beginning.

In S13, when a flow pulse from the flow meter 34 can be detected, it is determined that the flow meter 34 is normal, and the process proceeds to S14, where the density measurement value of the density meter 18 is output normally. Make sure that If there is an abnormality in the density measurement value of the density meter 18, the process proceeds to S14, issues an alarm, and returns to S11. In this case, the worker checks whether there is any abnormality in the density meter 18 and starts over from the beginning.

In S15, when the density measurement value of the density meter 18 is normally output, the flow proceeds to S16, where the oil liquid passing through the oil liquid supply pipe 14 is commutated so as to be supplied to the measuring tank 22. The commutation plate (not shown) of the vessel 20 is switched to start the flow measurement.

In the next step S17, at the same time as the switching operation of the commutation plate (not shown) of the commutator 20, the accumulation of the flow pulses output from the flow meter 34 is started. In S18,
It is checked whether the supply flow rate calculated from the integrated value of the flow pulse has reached 0.5 ton.

In S18, when the supply amount of the oil liquid supplied to the measuring tank 22 reaches 0.5 tons, the process proceeds to S19, in which the piston rods 62a of the hydraulic cylinders 62 to 65 are set.
６５65a is raised by one step. As a result, the lifting base 6
6 lifts the weight plate 58 ₁ of the bottom and one-step increase.
As a result, minute copper plate 58 _1, the flange portion 71 of the strut 71 to 74
a to 74a, the load is removed from the columns 71 to 74, and the weight 28 is placed on the reference scale 28.
The masses of the weight plates 58 _{2 to} 58 _n except for ₁ act. For example, the flow rate measurement before the start, the partial copper plate ₅₈ 1-58
_n mass 10 tons of consuming the reference scale 28, measuring tank 2
When 0.5 ton of the oil liquid is supplied to ₂ , the total value of 9.5 tons of the supplied oil liquid of 0.5 ton and the mass of the weight plates 58 _{2 to} 58 _n of 9 ton is supplied to the reference scale 28. Works.

In the next step S20, it is checked whether or not the supply flow rate calculated from the integrated value of the flow rate pulse is added by 1 ton.

In S20, when one ton of the oil liquid is additionally supplied to the measuring tank 22, the process proceeds to S21, and the piston rods 62a to 65a of the hydraulic cylinders 62 to 65 are further raised by one step. As a result, the lifting base 6
6 rises two steps from before the start of the flow rate and the weight plates 58 ₁ , 58
Lift ₂ As a result, the weight plates 58 ₁ and 58 ₂
The flanges 71a to 74a and the steps 71 ₁ to 71 of the columns 71 to 74
74 ₁ in a state in which removal of the load from the posts 71 to 74 spaced upwardly from the reference scale 28, the partial copper plate ₅₈ 1,
Mass of the weight plate ₅₈ 3 to 58 _n, except the 58 ₂ is in a state in which acts. For example, the oil solution 1.5 tons measuring tank 22 is supplied, the total value 10.5 tons of the mass 9 tons of minute copper plate ₅₈ 2 to 58 _n is applied to the reference scale 28. When the minute copper 58 _second mass by increasing the elevation base 66 is removed, the reference scale 28, the total value of 1.5 tons weight plate ₅₈ 3 to 58 _n mass 8 tons of hydraulic fluid 9. Five tons act on the reference scale 28.

In the next step S22, it is checked whether or not the supply flow rate calculated from the integrated value of the flow rate pulses output from the flow meter 34 has reached a target flow rate (for example, 10 tons). In S22, if the supply flow rate to the measuring tank 22 has not reached the target flow rate (for example, 10 tons), the processing of S20 to S22 is repeated. Then, in S22, when the supply flow rate to the measuring tank 22 reaches the target flow rate (for example, 10 tons), the process proceeds to S23, and the oil liquid that has passed through the oil liquid supply pipe 14 is supplied to the circulation recovery tank 24. Thus, the commutation plate (not shown) of the commutator 20 is returned to end the flow measurement. Thereafter, the process proceeds to S24, in which the pump 30 is stopped and the on-off valve 38 is closed to terminate the supply of the oil liquid.

At S25 shown in FIG. 6, the measured mass value measured by the reference balance 28 is read. At this time, about 10 tons of oil liquid is stored in the reference tank 16, and the weight plates 58 _{1 to} 58 _n are all placed on the elevating base 66 and lifted from the columns 71 to 74. Is displaced to the position Therefore, when the flow rate measurement is completed, the total mass of minute copper plate 58 ₁ to 58 _n is prevented from acting. Therefore, the mass of the oil liquid supplied to the reference tank 16 can be obtained by subtracting the masses of the reference tank 16 and the support 56 from the measurement value of the reference balance 28.

In the next step S26, the density of the oil liquid measured by the density meter 18 is read. In step S27, the flow rate measurement value measured by the flow meter 34 is calculated by the mass measurement value measured by the reference scale 28 and the density meter 18. A calibration process is performed based on the measured oil liquid density. When the high-precision flow meter 32 is calibrated, similarly to the case of the flow meter 34, the reference balance 28
The calibration process is performed based on the mass measurement value measured by the above and the density of the oil liquid measured by the density meter 18.

Subsequently, in S29, the pump 52 is started to return the oil liquid in the circulation recovery tank 24 to the storage tank 12, and the discharge valve 4 provided with the discharge pipe line 46 is provided.
8 is opened and the oil liquid in the measuring tank 22 is collected in the collecting tank 2
Discharge to 4.

In the next S30, it is checked whether or not 0.5 tons of the oil liquid in the measuring tank 22 has been discharged. This S
At 0.5, when 0.5 ton of the oil liquid in the measuring tank 22 is discharged, the process proceeds to S31, and the piston rods 62a to 65a of the hydraulic cylinders 62 to 65 are lowered by one step. As a result, the lifting base 66 is lowered by one step, and the uppermost weight plate 58 _n is placed on the step portions 71 _n to 74 _n of the columns 71 to 74.

As a result, a weight plate 58 _n
Is in the state of acting. For example, at the end of the flow rate measurement, the mass of 10 tons of the oil liquid stored in the measuring tank 22 is acting on the reference balance 28. .5 tons will weigh on the reference scale 28. When the minute copper plate 58 _n as described above is placed on the stepped portion ₇₁ n to 74 _n of the struts 71 to 74, hydraulic fluid 9.5 tons and the mass of the weight plate 58 _n left the weighing tank 22 A total value of 10.5 tons with 1 ton acts on the reference scale 28.

In the next step S32, it is checked whether or not one ton of the oil liquid in the measuring tank 22 has been discharged. If one ton of the oil liquid in the measuring tank 22 is discharged in S32, the process proceeds to S33, in which the piston rods 62a to 65a of the hydraulic cylinders 62 to 65 are further lowered one step. Thus, the elevating base 66 is lowered a weight plate ₅₈ n, _{58 n-1} descends bunk than the flow rate at the end, minute copper plate ₅₈ n, ₅₈ flange portion 71 of the _n-1 the strut 71 to 74 _{n -1} to 74 _n-1 . Therefore, the weight (2 tons) of the weight plates 58 _n and 58 _n−1 is provided on the reference scale 28.
Is in effect.

For example, when 0.5 ton of oil liquid is discharged from the measuring tank 22, the mass of 9.5 ton
Acts on 8. Then, when the lifting base 66 is lowered by one step, a total value of 10.5 tons of the mass 1 _n of the weight plate 58 _n and the mass 9.5 ton of the oil liquid acts on the reference scale 28.

Next, when 1.5 tons of the oil liquid is discharged from the measuring tank 22, the mass of the oil liquid is 8.5 tons and the weight plate 58 is discharged.
The total weight of 9.5 tons with 1 ton of _n
Acts on 8. Then, when the lifting base 66 is lowered by two steps, the mass of the oil liquid is 8.5 tons and the weight plates 58 _n , 58 _n−1.
The total value of 20.5 tons and 10.5 tons acts on the reference scale 28.

In the next step S34, it is checked whether or not all the oil has been discharged from the measuring tank 22. If the oil liquid remains in the measuring tank 22 in S34, the processes of S32 to S34 are repeated. When all the oil liquid in the measuring tank 22 has been discharged in S34, S3
Proceeding to 5, the pump 52 is stopped, and the discharge valve 48 is closed. Thus, the flow meter calibration processing ends.

As described above, when the oil liquid is supplied to the measuring tank 22, the weight of the weight plates 58 _{1 to} 58 _n is removed one by one by raising the lifting base 66 step by step. 28 always has a mass of 9.5 to 10.5 tons. Therefore, in the reference scale 28, the hysteresis due to the load fluctuation is reduced, and the measurement accuracy can be improved. Similarly, when the oil liquid in the measuring tank 22 is discharged after the flow rate measurement is completed, the oil liquid in the measuring tank 22 is discharged, and the lifting base 66 descends in a stepwise manner so that the masses of the weight plates 58 _{1 to} 58 _n are reduced. Since the reference balance 28 is increased one by one and acts on the reference balance 28, the reference balance 28 always has 9.5 to 9.5.
Since 10.5 tons of mass acts, hysteresis due to load fluctuation is reduced and measurement accuracy can be improved.

FIG. 7 is a block diagram showing a modification of the present invention.

As shown in FIG. 7, the weight plates 58 _{1 to} 5 5 are provided below the support 56 supporting the measuring tank 22.
Liquid weight tank 80 as a weight of (water or oil solution) was reservoir is provided in place of 8 _n. A liquid level sensor 82 for detecting a liquid level is inserted inside the weight tank 80.

The bottom of the weight tank 80 is connected to a recovery tank 84 provided outside via a discharge pipe 86. The discharge pipe 86 is provided with a discharge pump 88 for sending the liquid stored in the weight tank 80 to the recovery tank 84 and a flow control valve 89. Further, the bottom of the recovery tank 84 is connected to the weight tank 80 via a return line 90, and a return pump 92 and a flow control valve 93 are provided in the return line 90.

For example, before the flow rate measurement, 1
Zero tons of liquid is stored as a weight. Then, the oil liquid is supplied into the measuring tank 22 and the pump 88 is started to discharge the liquid in the weight tank 80 to the collection tank 84. When the flow rate measurement is completed, all the liquid in the weight tank 80 is discharged. At this time, the flow control valve 8
9, the flow rate of the liquid discharged from the weight tank 80 is adjusted to be substantially the same as the flow rate of the oil liquid supplied to the measuring tank 22, so that the load acting on the reference scale 28 is always maintained at about 10 tons. As a result, the load variation can be extremely small. Thereby, the hysteresis due to the load fluctuation of the reference scale 28 is reduced, and the measurement accuracy can be improved.

After the flow rate measurement, when the oil liquid supplied to the measuring tank 22 is discharged to the circulation recovery tank 24,
The pump 92 is activated so that the liquid in the collection tank 84 is returned to the weight tank 80. At this time, the flow rate of the liquid supplied to the weight tank 80 is adjusted by the flow rate adjusting valve 93 so as to be substantially the same as the flow rate of the oil liquid discharged from the measuring tank 22, so that the load acting on the reference scale 28 is reduced. It is always maintained at about 10 tons, and the load fluctuation can be suppressed to a very small level. Thereby, the hysteresis due to the load fluctuation of the reference scale 28 is reduced, and the measurement accuracy can be improved.

In the above-described embodiment, the measurement accuracy of the flow meter 34 was verified using kerosene or light oil. However, the present invention is not limited to this, and it is a matter of course that other oil liquids can be used.

In the above-described embodiment, the configuration in which the other end of the bypass pipe 16 is inserted into the circulation recovery tank 24 and is open to the atmosphere has been described as an example. However, the present invention is not limited to this. The other end of the path 16 is connected to the recovery tank 2 for circulation.
Of course, it may be configured to be inserted into another tank or the like other than 4 and open to the atmosphere.

In the above embodiment, the measuring tank 2
2 is 10 tons, each weight plate 58 _1- of the weight mechanism 26.
Although the mass of 58 _n was set to 1 ton, it goes without saying that the mass is not limited to these values.

In the above embodiment, the weight mechanism 26
Not only the number of the weight plates 58 ₁ to 58 _n to have been a ten, the may be 10 or more in 10 sheets or less is a matter of course.

In the above embodiment, the measuring tank 2
Weight plates 58 _{1 to} 58 according to the supply amount when supplying the oil liquid to
_n is gradually removed, and after the flow meter is calibrated, the measuring tank 2 is removed.
The weight plates 58 ₁ to 58 ₁ according to the discharge amount when discharging the oil liquid of _{No. 2}
While 58 _n and configured to add a stepwise load,
It is not always necessary to perform both supply and discharge, and at least when supplying the oil liquid to the measuring tank 22, the weight plates 58 _{1 to} 58 _n are removed stepwise according to the supply amount. The object of the present invention can be achieved. Desirably, if both the supply and the discharge are performed, the accuracy can be further improved.

In the above modification, the weight plate 58 ₁
To 58 _n in place of the discharge amount when the hydraulic fluid in accordance with the supply amount at the time of supply to discharge the hydraulic fluid from the weight tank 80, to discharge the hydraulic fluid in the metering tank 22 after calibration of the flow meter to the metering tank 22 Is configured to supply the oil liquid to the weight tank 80 in accordance with the above, but it is not always necessary to perform both the supply and the discharge, and at least when supplying the oil liquid to the measuring tank 22,
The object of the present invention can be achieved by a configuration in which the oil liquid in the weight tank 80 is discharged. Preferably,
If both supply and discharge are performed, the accuracy can be further improved.

As described above, according to the first aspect of the present invention, since the other end of the bypass pipe is open to the atmosphere, the bypass pipe provided with the density meter without providing an orifice in the oil liquid supply path. Sufficient oil liquid can be supplied to the passage, and the flow meter can be calibrated accurately. Also,
Even when calibrating the flowmeters having different sizes, the flowmeter is not affected by the flow velocity change due to the orifice of the oil liquid supply path, so that the flowmeter can be calibrated accurately.

According to the second aspect of the present invention, the driving means is driven in accordance with the measurement value or the mass measurement value of the flow meter, and a plurality of driving means are provided in response to an increase in the amount of oil supply to the measuring tank. By removing the divided weights in stages, the change in the load applied to the mass measuring means can be reduced to reduce the measurement error due to hysteresis when measuring the mass of the measuring tank, and to calibrate the flow meter accurately. it can.

According to the third aspect of the present invention,
By driving the pump in accordance with the measurement value of the flow meter and discharging the liquid stored in the weight tank in response to the increase in the amount of oil liquid supplied to the measurement tank, the discharge flow rate from the weight tank to the measurement tank It is possible to minimize the change in load applied to the mass measuring means at the same level as the supply flow rate of the weighing tank, reduce the measurement error due to hysteresis when measuring the mass of the measuring tank, and accurately calibrate the flow meter Can be.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a flow meter calibration system according to the present invention.

FIG. 2 is an enlarged perspective view showing a configuration of a weight mechanism 26;

FIG. 3 is an enlarged front view showing a configuration of a weight mechanism 26;

FIG. 4 is an exploded perspective view showing a main part of the weight mechanism.

FIG. 5 is a flowchart of a control process executed by a control unit 54;

FIG. 6 is a flowchart illustrating a process performed after the process of FIG. 5;

FIG. 7 is a configuration diagram showing a modification of the present invention.

[Explanation of symbols]

Reference Signs List 10 flow meter calibration system 12 storage tank 14 oil supply line 16 bypass line 18 density meter 20 commutator 22 measuring tank 24 circulation recovery tank 26 weight mechanism 28 reference scale 30 first pump 32 high precision flow meter 34 flow rate Total 36 Flow control valve 38 Open / close valve 40 Flow control valve 46 Discharge line 48 Discharge valve 50 Reflux line 52 Second pump 56 Support base 58 _{1 to} 58 _n Weight plate 60 Operating device 62 to 65 Hydraulic cylinder 66 Lifting base 71 to 71 74 struts 76 ₁ to 76 _n insertion hole 71a~74a flange portion _{71 1 ~71 n, 72 1 ~72} n, 73 1 ~73 n, 7
4 _{1 to} 74n Step portion 80 Weight tank 82 Liquid level sensor 84 Recovery tank 86 Discharge line 88,92 Pump 89,93 Flow control valve 90 Reflux line

Claims (3)

[Claims] 1. An oil liquid supply path for supplying an oil liquid in a storage tank, a pump for supplying the oil liquid via the oil liquid supply path, and a pump attached to the oil liquid supply path and supplying the oil liquid by the pump. A flow meter as a test meter for measuring the measured oil liquid; a measuring tank to which the oil liquid measured by the flow meter is supplied; and a bypass pipe branched from the oil liquid supply path upstream of the flow meter. A density meter attached to a road, and mass measuring means for measuring the mass of the measuring tank, and arithmetically compares the measured value of the flow meter with the measured value of the mass measuring device and the measured value of the density meter A flowmeter calibration system configured to calibrate the flowmeter, wherein the other end of the bypass pipe is open to the atmosphere. 2. An oil liquid supply path for supplying an oil liquid in a storage tank, a pump for supplying the oil liquid through the oil liquid supply path, and a pump attached to the oil liquid supply path and supplying the oil liquid by the pump. A flow meter as a test meter for measuring the measured oil liquid; a measuring tank to which the oil liquid measured by the flow meter is supplied; and a bypass pipe branched from the oil liquid supply path upstream of the flow meter. A density meter attached to a road, and mass measuring means for measuring the mass of the measuring tank, and arithmetically compares the measured value of the flow meter with the measured value of the mass measuring device and the measured value of the density meter A flow meter calibration system configured to calibrate the flow meter, having a mass equal to the mass of the maximum amount of oil liquid to be measured, a weight divided into a plurality, and divided into a plurality of weights. The weight as appropriate for the mass measuring means Driving means for mounting, or removing as appropriate, driving the driving means in accordance with the measurement value or mass measurement value of the flow meter, in response to an increase in the amount of oil liquid supplied to the measuring tank, the plurality of And a control unit for controlling the weights divided in steps so as to remove the weights in a stepwise manner. 3. An oil liquid supply path for supplying an oil liquid from a storage tank, a pump for supplying the oil liquid via the oil liquid supply path, and a pump attached to the oil liquid supply path and supplying the oil liquid by the pump. A flow meter as a test meter for measuring the measured oil liquid; a measuring tank to which the oil liquid measured by the flow meter is supplied; and a bypass pipe branched from the oil liquid supply path upstream of the flow meter. A density meter attached to a road, and mass measuring means for measuring the mass of the measuring tank, and arithmetically compares the measured value of the flow meter with the measured value of the mass measuring device and the measured value of the density meter A flow meter calibration system configured to calibrate said flow meter, said liquid having a mass equal to the mass of said metering tank containing a maximum amount of oil liquid to be measured, said liquid being mounted on said mass measuring means. To store the weight A pump for discharging the liquid stored in the weight tank; driving the pump in accordance with a value measured by the flow meter; and adjusting the weight tank in response to an increase in the amount of oil liquid supplied to the measuring tank. And a control unit for controlling to discharge the liquid stored in the flowmeter.