JP3154346B2 - Tank remaining amount 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 an apparatus for measuring the remaining amount in a storage tank for storing a liquid such as gasoline, which is buried underground in a gas station, for example. The present invention relates to a tank remaining amount measuring device capable of accurately measuring a remaining amount in a liquid storage tank deformed by pressure or the like.

[0002]

2. Description of the Related Art In general, at a gas station, a storage tank for storing oil such as gasoline is buried under the site of the gas station, and the remaining amount of oil in the storage tank is monitored. For this purpose, a tank remaining amount measuring device including a liquid level sensor for detecting the liquid level of the oil liquid and a control device such as a liquid level gauge is provided.

FIG. 5 to FIG. 8 show an example of a conventional tank remaining amount measuring device for monitoring the remaining amount of oil in a liquid storage tank provided underground on a gas station site as a conventional tank remaining amount measuring device. Are shown below.

In the drawing, reference numeral 1 denotes a gas station site, and a building 2 such as an office, a pump,
A meter (not shown) including a flow meter, a refueling nozzle and the like is provided, and a plurality of liquid storage tanks 4 described below are buried under the refueling station premises 1.

[0005] Reference numeral 3 denotes a plurality of tank chambers (only one is shown) under the gas station site 1, and at the bottom of each tank chamber 3, pillows 3 A, 3 A on which a liquid storage tank 4 is placed. Are integrally formed. Reference numeral 4 denotes a liquid storage tank provided in each of the tank chambers 3, and each of the liquid storage tanks 4
Are fixed via fixed bands (not shown) on each of the pillows 3A, and store an oil liquid such as gasoline therein. In addition, a manhole 5 is provided on the upper side of each of the liquid storage tanks 4 to open to the gas station site 1 via the tank room 3, and a dry sand is provided between each of the liquid storage tanks 4 and the tank room 3. 6 are filled. Further, a ventilation pipe (not shown) is connected to each of the liquid storage tanks 4, and the liquid storage tank 4 is connected with the ventilation pipes.
The oil vapor (vapor) inside is released to the outside.

Reference numeral 7 denotes an oil-absorbing pipe which is located in the basement of the gas station site 1 and is connected to each of the measuring machines and each of the liquid storage tanks 4. Each of the check valves provided in the middle of the
Is for permitting the oil liquid to flow from the liquid storage tank 4 to the measuring machine and for preventing the reverse flow.

9 is another manhole provided at one corner of the gas station site 1, and 10 is a tank truck from each tank 4
An injection pipe for injecting an oil solution is shown, and one end of each injection pipe 10 is provided in the manhole 9 and becomes an injection port 10A.
The other end is connected to the liquid storage tank 4. When the remaining amount of the oil liquid in the liquid storage tank 4 becomes low, each of the injection pipes 10 is connected to an oil supply hose (not shown) of the tank lorry to the inlet 10A, and Is supplied into the liquid storage tank 4.

Reference numerals 11, 11,... Denote liquid level sensors inserted into the respective liquid storage tanks 4.
As shown in, for example, Japanese Patent Application Laid-Open No. 54-14266, a so-called coaxial cylindrical type comprises a metal inner cylinder and a metal outer cylinder (both not shown) provided coaxially with the inner cylinder. As shown in FIG. 6, it is connected to a liquid level gauge 13 described later via an intrinsically safe explosion-proof box 12 (an intrinsically safe box). Each of the liquid level sensors 11 detects a capacitance generated between the inner cylinder and the outer cylinder, and determines the detected capacitance as a liquid depth L (liquid level) of the oil liquid in each of the storage tanks 4. (Height) to the liquid level gauge 13.

Reference numeral 13 denotes a liquid level gauge provided in the building 2 and constituted by a microcomputer or the like as a remaining amount calculating means.
As shown in FIG. 1, an arithmetic circuit 14 including a CPU, an I / O circuit, and the like, and a storage circuit 1 including a ROM, a RAM, and the like.
5 is provided on the front side of the casing 13A of the liquid level gauge 13. The display unit 16 displays the remaining amount of the oil liquid, and a numeric keypad for designating the liquid storage tank 4 and the like. A setting switch 17, a printer 18, and an alarm buzzer 19 for issuing an alarm when the remaining amount in the liquid storage tank 4 becomes low are provided. Further, in the storage circuit 15, various tank types of the liquid storage tank 4 which are different depending on the vertical tank, the horizontal tank, the presence / absence of mirroring, etc., and the liquid depth L and the oil liquid corresponding to each tank type, respectively. An arithmetic expression indicating a relationship with the remaining amount Q, a tank table 20 described later, and the like are stored.

The liquid level gauge 13 is provided with a liquid level sensor 1.
The remaining amount Q of the liquid storage tank 4 is obtained from the tank table 20 on the basis of the detection signal (liquid depth L) from 1 and is displayed on the display unit 16 when the remaining amount Q reaches a predetermined lower limit. The warning buzzer 19 and the like are operated to warn the worker of the need for refueling.

Reference numeral 20 denotes a tank table stored in the storage circuit 15. As shown in FIG. 7, the tank table 20 is prepared in advance for each liquid storage tank 4 by a tank table preparation processing program described later. The relationship between the liquid depth L in the liquid storage tank 4 and the remaining amount Q is shown.

Next, a tank table creation process for creating the tank table 20 will be described with reference to FIG.

First, in step 1, the operator sets and inputs the tank type of the storage tank 4 and the type of the liquid level sensor 11 via the setting switch 17, and in step 2, the liquid depth corresponding to the tank type is set. The arithmetic expression of L and the remaining amount Q is read out from the storage circuit 15 and set, and in the next step 3, the tank dimensions such as the body length, radius, mirroring function of the liquid storage tank 4 are described in the product specification and the like. Input based on the design value described in.

Then, in step 4, the remaining amount Q when the liquid depth L is changed, for example, every 1 mm is calculated based on the above-mentioned arithmetic expression. The relationship between the liquid depth L and the remaining amount Q is determined until the tank state is reached and “YES” is determined, and thereby the theoretical tank table 20 is created. Finally step 6
Then, the tank table 20 is registered and stored in the storage circuit 15, and the processing is terminated.

The conventional apparatus for measuring the remaining amount of water in a tank has the above-described configuration. The liquid level gauge 13 is based on the liquid depth L of the liquid storage tank 4 output from the liquid level sensor 11.
The remaining amount Q calculated in advance corresponding to the liquid depth L is read from the tank table 20, and the remaining amount Q is monitored while being displayed on the display unit 16. Then, when the remaining amount Q in the liquid storage tank 4 reaches a predetermined lower limit value, a warning is issued to the operator via the display unit 16, the alarm buzzer 19, and the like in order to prompt the refueling by the tank truck.

[0016]

In the above-described conventional apparatus for measuring the remaining amount of liquid in a tank, a tank table showing a relationship between the liquid depth L and the remaining amount Q in the liquid storage tank 4 in advance by a tank table creation process. Since the table 20 is prepared and stored, and the remaining amount Q of the liquid storage tank 4 is monitored based on the tank table 20, the remaining amount Q is obtained in a short time based on the liquid depth L from the liquid level sensor 11. be able to. However, since the tank table 20 is created based on the design dimensions of each part of the liquid storage tank 4 described in advance in a product specification or the like, the theoretical relationship between the liquid depth L and the remaining amount Q is determined. It only shows.

For this reason, according to the above-described prior art, if there is a manufacturing error in the liquid storage tank 4 or if distortion occurs due to an impact during transportation and installation work, the liquid depth L in the tank table 20 is reduced. And the remaining amount Q differs from the actual relationship, and the remaining amount Q cannot be measured with high accuracy.
There is a problem that reliability is greatly reduced. For example, when the actual relationship between the liquid depth L and the remaining amount Q changes as shown by the two-dot chain line in FIG. 7 due to the deformation of the liquid storage tank 4, when the liquid depth L is L1, the tank table Although the remaining amount Q displayed by the display unit 16 based on 20 is Q1, the actual remaining amount is Q1 ', and there is a difference between the displayed value and the actual value.

In general, a device for measuring the remaining amount in a tank includes:
Based on the remaining amount Q, the oil liquid is monitored for theft, oil leakage, and the like.
There is a problem that the detection accuracy of oil leakage and the like also decreases, and reliability and safety decrease.

In particular, the liquid storage tank 4 buried under the gas station site 1 is deformed by the pressure such as earth pressure and vehicle weight as shown in FIG. Therefore, the relationship between the actual liquid depth L and the remaining amount Q greatly deviates from the theoretical tank table 20, and the measurement error increases.
There is a problem that reliability is reduced.

Further, the liquid storage tank 4 does not deform unless it is actually installed in the tank chamber 3, and it is difficult to confirm the deformation state of the liquid storage tank 4 from the outside. Since the degree of deformation differs depending on various conditions such as the method of burying the liquid storage tank 4, the tank table 20 cannot be created in anticipation of the deformation of the liquid storage tank 4 in advance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and accurately corrects the relationship between the liquid depth and the remaining amount in a tank table in accordance with the deformation of a liquid storage tank, and provides a practical tank table. It is an object of the present invention to provide a tank remaining amount measuring device capable of measuring a liquid remaining amount in a liquid storage tank with high accuracy by creating a liquid storage tank.

[0022]

A feature of the structure adopted by the present invention to solve the above-mentioned problem is that a predetermined amount of liquid is filled in the liquid storage tank in a state where the liquid storage tank is empty. A predetermined amount injecting means for injecting, and a tank for correcting the relationship between the liquid depth and the remaining amount in the tank table with the predetermined amount of liquid injected by the predetermined amount injecting means as a regular remaining amount of the liquid storage tank. That is, a table correction means is provided.

[0023]

With the above arrangement, when the predetermined amount of liquid is injected into the empty liquid storage tank by the predetermined amount by the predetermined amount injection means, the tank table correction means sets the amount of liquid injected by the predetermined amount as a regular remaining amount. The state is correlated with the liquid depth detected by the liquid level sensor in the state, and the relation between the liquid depth in the tank table and the remaining amount is corrected.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those in the prior art shown in FIGS. 5 to 8 are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 21 denotes a tank truck as a predetermined amount injection means. The tank truck 21 carries a tank 22, and the tank 22 has, for example, five oil chambers 22A and 22A.
A,... And a predetermined amount of liquid, specifically, 2 kiloliters of oil liquid, is stored in each of the oil chambers 22A. The tank truck 21 connects the oil supply hose 23 to the inlet 10A of the injection pipe 10 to sequentially supply the oil liquid in each oil chamber 22A into the liquid storage tank 4.

Here, the amount of oil contained in each oil chamber 22A of the tank 22 is measured by a flow meter on the tank lorry shipping device side with an accuracy within 0.2 to 0.5%, for example, an accuracy of 0%. .2%, and the time required to supply the oil liquid in each oil chamber 22A to the liquid storage tank 4 is usually
It is about 4 to 8 minutes per room.

Numeral 24 denotes a liquid level gauge as a remaining amount calculating means according to the present embodiment. The liquid level meter 24 has a casing 24A as shown in FIG. An arithmetic circuit 25 and a storage circuit 26 are accommodated therein, and a display unit 16, a setting switch 17, a printer 18, and an alarm buzzer 19 are provided on the front side of the casing 24A. However, the liquid level meter 24 according to the present embodiment includes the arithmetic circuit 2
5 is connected to a correction switch 27, and a storage circuit 26 stores a practical tank table 20 'described later shown in FIG. 3 and a program shown in FIG.

The apparatus for measuring the remaining amount in a tank according to the present embodiment has the above-described configuration, and there is no particular difference in managing the remaining amount based on the tank table from the prior art. Therefore, a tank table correction process which is a feature of the present embodiment will be described with reference to FIG.

Here, it is necessary to empty the liquid storage tank 4 as a precondition for performing the tank table correction processing.
There are cases such as cleaning foreign matter and water accumulated inside, inspection of oil leakage, etc.
May be emptied.

First, at step 11, the storage tank 4 is designated. At step 12, the theoretical tank table 20 corresponding to the storage tank 4 is read from the storage circuit 26. At step 13, the tank truck 21 is read. Is connected to the inlet 10A of the injection pipe 10 and the tank 2
The oil in the oil chamber 22A from two to one, that is, 2 kiloliters of the oil Q2 'as a predetermined amount of liquid is supplied into the storage tank 4. During the refueling in step 13, a complementing operation described later is performed.

Then, at step 14, the operator inputs that 2 kiloliters of oil has been supplied through the setting switch 17, and at step 15, the total refueling amount C as a refueling counter is calculated. Here, initially, only 2 kiloliters are supplied to the liquid storage tank 4, so that the total refueling amount C is 2 kiloliters (C = Q2 ').

Next, at step 16, the liquid level sensor 11
The detection signal is read from the tank table 20 in step 17 based on the liquid depth L2 from the liquid level sensor 11.
The remaining amount Q2 is obtained from the above, and the liquid depth L2 and the remaining amount Q2 are displayed on the display unit 16. In step 18, the operator sets the display value Q
It is determined whether or not 2 and the actual refueling amount C substantially match.

Here, as shown by a two-dot chain line in FIG. 3, if the liquid storage tank 4 is deformed due to earth pressure or the like,
When the oil quantity Q2 'of kiloliters is supplied, the liquid depth L is L2
However, according to the theoretical tank table 20, the theoretical remaining amount Q at this liquid depth L2 is Q2, and the difference between the actually supplied oil amount Q2 'and the indicated value Q2. Occurs. Therefore, when the total refueling amount C is different from the display value Q2, it means that the liquid storage tank 4 is deformed, so that the operator determines "NO" in step 18 and the correction switch 27 in the next step 19. Turn on.

On the other hand, when the total refueling amount C substantially matches the indicated value Q2, the liquid storage tank 4 is not deformed at least up to the range of the liquid depth L2.
Then, the operator makes a determination of "YES" and inputs that confirmation has been made in a step not shown, and then proceeds to step 21 described later.

Then, in step 20, the actually refueled oil amount Q2 'is set as the regular remaining amount Q in the liquid storage tank 4.
The remaining amount Q corresponding to the liquid depth L2 is calculated from the theoretical value Q2 to the actual oil amount Q.
Change to 2 'and correct the tank table 20. Here, when the remaining amount Q is in the range of 0 to 2 kiloliters, the correction rate in the theoretical range of the tank table 20 is proportionally distributed according to the correction rate from the theoretical value Q2 to the actual oil amount Q2 '. Is corrected so as to be curved. It should be noted that the processing in step 20 is calculated and complemented during the next refueling time performed in step 13.

Next, at step 21, the liquid level sensor 11
It is determined whether or not the liquid storage tank 4 is full based on the liquid depth L from the above. If not, “NO” is determined and the process returns to step 13;
S ”, and proceeds to step 22 described below. here,
Since only 2 kiloliters of oil has been supplied to the storage tank 4, the process returns to step 13.

Then, the operator supplies a new 2 kiloliters of oil from the next oil chamber 22A of the tank 22 to the storage tank 4A.
By repeating the processing of steps 13 to 21 described above, the remaining amount Q corresponding to the liquid depth L4 is reduced in a state where the total refueling amount C is 4 kiloliters (C = Q4 '). Is changed from the theoretical value Q4 based on the tank table 20 to the actual oil amount Q4 'actually supplied, and the tank table 20 is corrected.

Similarly, when a total of 6 kiloliters of the oil Q6 'is supplied from the tank 22 (C = Q6'), 8
When kiloliters of oil liquid Q8 'is charged (C = Q
8 ') When 10 kiloliters of oil liquid Q10' is injected (C = Q10 '), the remaining amounts Q corresponding to the respective liquid depths L6, L8, L10 are fixedly corrected, and the intermediate range is adjusted. The theoretical tank table 20 is changed to a practical tank table 20 ′ according to the deformation of the liquid storage tank 4 by performing a complementary operation during the refueling time.

Here, when the remaining amount Q is 0 kiloliter and 10 kiloliter, the liquid storage tank 4
Does not cause an error in the theoretical tank table 20, the determination in step 18 is “YES”, and the tank table 20 is not corrected.

Finally, at step 22, the practical tank table 20 'thus corrected is stored in the storage circuit 26.
The correction processing is completed, and the remaining amount management is performed based on this practical tank table 20 '.

Thus, according to the present embodiment, two oil chambers 22A of the tank 22 of the tank truck 21 are supplied with the oil liquid, which has been managed with an accuracy of, for example, within 0.2%, in the empty storage tank 4 in advance. By refueling by kiloliters, the remaining amount Q corresponding to the liquid depth L from the liquid level sensor 11 at this time is changed from the theoretical display values Q2 to Q8 to the actual oil amounts Q2 'to Q8'. The theoretical tank table 20 is replaced with a practical tank table 20 ′ corresponding to the deformation of the liquid storage tank 4.
Can be effectively corrected, and the measurement accuracy of the remaining amount management can be greatly improved.

As a result, even if the liquid storage tank 4 is deformed due to manufacturing errors, impact during transportation, earth pressure after installation, etc., it is possible to take advantage of opportunities such as opening a gas station or cleaning a tank.
The tank table 20 according to the degree of deformation of the liquid storage tank 4
Can be obtained to obtain a practical tank table 20 ′. Therefore, the remaining amount Q can be accurately measured from the tank table 20 ′ based on the liquid depth L from the liquid level sensor 11, and The accuracy of detection of leakage and the like can be increased, and safety, reliability, and the like can be significantly improved.

Further, since the tank table 20 is corrected by supplying two kiloliters of oil at a time from the tank 22 of the tank truck 21, the time required for the correction process is, for example, about 30 minutes to 1 hour. Can be shortened. As a result, the correction process can be performed promptly while the amount of vapor discharged from the liquid storage tank 4 to the outside via the ventilation pipe is small, that is, before the oil liquid in the liquid storage tank 4 decreases. The tank table 20 can be corrected more accurately.

The program shown in FIG. 4 is a specific example of the tank table correcting means which is a component of the present invention.

In the above embodiment, the tank truck 2
Although the case where two kiloliters of oil are supplied from one tank 22 has been described as an example, for example, the oil chamber 22A of the tank 22 is described.
If there are two types, i.e., 2 kiloliters and 4 kiloliters, it can be applied by inputting which oil amount has been supplied in step 14.

Further, in the above-described embodiment, the case where the in-tank remaining amount measuring device is used for the liquid storage tank 4 of the gas station has been described as an example. However, the present invention is not limited to this.
The present invention can be widely applied to a remaining amount measuring device for a tank for storing other liquids such as alcohol and chemicals.

[0047]

As described above in detail, according to the present invention, when a predetermined amount of liquid is injected into an empty liquid storage tank by a predetermined amount by the predetermined amount injection means, the tank table correction means is injected by this predetermined amount. The liquid volume is assumed to be the normal remaining amount, and in this state, the liquid level is related to the liquid depth detected by the liquid level sensor, and the relationship between the liquid depth in the tank table and the remaining amount is corrected. If the tank table is deformed due to the error of the tank, the shock during transportation, the earth pressure after installation, etc., take advantage of the opportunity of cleaning the tank, etc., and correct the tank table according to the degree of deformation of the liquid storage tank. You can get a tank table. As a result, the remaining amount can be accurately measured from the tank table based on the liquid depth from the liquid level sensor, and the detection accuracy of theft, leakage, and the like can be improved, and safety, reliability, and the like can be improved. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an apparatus for measuring a remaining amount in a tank according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a remaining amount measuring device in a tank.

FIG. 3 is an explanatory diagram showing a tank table corrected by a tank table correction process.

FIG. 4 is a flowchart showing a tank table correction process stored in a liquid level gauge.

FIG. 5 is an overall configuration diagram showing a conventional tank remaining amount measuring device.

FIG. 6 is a block diagram showing a circuit configuration of a conventional apparatus for measuring the remaining amount in a tank.

FIG. 7 is an explanatory view showing a tank table.

FIG. 8 is a flowchart showing a tank table creation process.

[Explanation of symbols]

 Reference Signs List 4 liquid storage tank 11 liquid level sensor 20, 20 'tank table 21 tank truck (predetermined amount injection means) 24 liquid level gauge (remaining amount calculating means) L liquid depth Q remaining amount

Claims (1)

(57) [Claims] 1. A liquid level sensor provided in a liquid storage tank for detecting a liquid depth of a liquid contained in the liquid storage tank, and a liquid depth of the liquid storage tank based on a shape of the liquid storage tank. And calculating a remaining amount in the storage tank from the tank table based on a tank table in which a relationship between the storage amount and the remaining amount is calculated and stored in advance, and a liquid depth of the storage tank detected by the liquid level sensor. A remaining amount calculating device for performing a predetermined amount injection of a predetermined amount of liquid into the storage tank in a state where the storage tank is empty; Tank table correction means for correcting the relationship between the liquid depth and the remaining amount in the tank table with the predetermined amount of liquid injected by the fixed amount injection means as the normal remaining amount of the liquid storage tank. Characteristic device for measuring remaining amount in tank.