JP2014054996A - Oil mixture prevention device for liquid level measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil mixture in a storage tank by positively utilizing a function of a liquid level meter with a density measurement function.SOLUTION: An oil mixture prevention device for a liquid level measurement device includes: a float 6 for density detection which is guided by a stem 3 and which sinks and floats according to the density of fuel oil; a float 5 for water detection which is guided by the stem 3 and which sinks and floats according to the level of water; an elastic body 7 which connects the float 6 for density detection and the float 5 for water detection; means 11 for detecting a distance between the float 6 for density detection and the float 5 for water detection; reference temperature density calculation means 13 which calculates the density of the fuel oil on the basis of the distance, and which calculates reference temperature density at a reference temperature; and density determination update means 14 which notifies the mixture of oil when the density from the reference temperature density calculation means 13 is out of a threshold value with respect to the reference temperature density which is registered for each oil type from the reference temperature density.

Description

  The present invention relates to a technique for preventing mixed oil at the time of unloading to a storage tank by a tank truck.

A tank truck that delivers fuel oil to a gas station is divided into a plurality of hatches (oil tank chambers) by a partition plate, and is configured so that different types of fuel oil can be mounted on each hatch.
On the other hand, a storage tank that stores a plurality of oil types such as gasoline, kerosene, and light oil is provided for each oil type. The unloading from the tank truck to each storage tank is performed by the operator opening a bottom valve provided on the tank truck side.

  By the way, when unloading fuel oil from a tank truck to a storage tank, an operator mistakenly connects an oil supply hose of the tank truck to a storage tank of a different oil type, and unloads fuel oil of a different oil type to the storage tank. There is a risk.

  In order to avoid such an accident, a method using an identification piece as proposed in Patent Document 1 has also been proposed, but there is a risk that additional equipment is required for preventing mixed oil and equipment investment is increased. In addition, there is a problem that there is no guarantee that the collation with the cargo fuel oil can be obtained even if the collation on the data is obtained.

JP 2000-327099 A JP 2012-2618 A JP 2010-217082 A JP 2011-148526 A

On the other hand, as shown in Patent Document 2, a liquid level gauge with a density measuring function is about to be put into practical use.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a device capable of preventing oil mixture in a storage tank by actively utilizing the function of a liquid level gauge with a density measuring function. Is to provide.

In order to achieve such a problem, the present invention provides a density detection float that is guided by a stem and floats and sinks corresponding to the density of fuel oil, and a water detection that is guided by the stem and floats and sinks according to the water level. A float, an elastic body connecting the density detection float and the water detection float, a means for detecting a distance between the density detection float and the water detection float, and a density of the fuel oil based on the distance A reference temperature density calculating means for calculating a reference temperature density at the reference temperature, and the density from the reference temperature density calculating means is a threshold value with respect to the reference temperature density registered for each oil type from the reference temperature density. And a density determination updating means for informing the mixed oil when outside.

Since the density of the fuel oil in the storage tank can be monitored online, the mixed oil can be reliably detected.

It is the schematic which shows one Example of this invention. It is a block diagram which shows one Example of this invention. It is a flowchart which shows operation | movement of an apparatus same as the above. It is a diagram which shows the relationship between the distance between floats and the density of fuel oil. It is a diagram which shows the operation | movement in one year of an apparatus same as the above. It is a diagram which shows the operation | movement at the time of oiling of an apparatus same as the above.

Therefore, the details of the present invention will be described below based on the illustrated embodiment.
FIG. 1 shows an embodiment of a mixed oil prevention device of the present invention. A liquid level gauge 1 with a function installed in a fuel storage tank T is a stem 3 installed vertically in a riser pipe 2. A magnetostrictive wire is stretched at the center of the inside, and a detection coil is wound around it as seen in Patent Document 2 as a receiving means, or a piezoelectric vibrator at one end as seen in Patent Document 3 Is arranged.

  On the other hand, a liquid level detection float 4 provided with a magnetic body 4a on the outer periphery of the stem 3, and a water detection float 5 that settles on fuel oil near the bottom, floats on water, and is provided with a magnetic body 5a. A density detecting float 6 that floats and sinks due to the specific gravity of the fuel oil and includes a magnetic body 6 a is disposed, and the water detecting float 5 and the density detecting float 6 expand and contract in accordance with the float and sink of the float 6. It is connected by an elastic body 7 of a degree.

    The signal processing device 10 outputs a pulse signal to the coil, transmits a shock wave to the magnetostrictive wire toward the other end, and receives the reflected wave from the magnetic bodies 4a, 5a, 6a of the floats 4, 5, 6 by the coil. In addition, a shock wave is transmitted toward the other end of the magnetostrictive line by the piezoelectric vibrator, and the reflected waves from the magnetic bodies 4a, 5a, and 6a of the floats 4, 5, and 6 are received by the piezoelectric vibrator. The liquid level and density are measured based on the time difference of the reflected waves from the magnetic bodies 4a, 5a, and 6a of the floats 4, 5, and 6, and an alarm is issued when a mixed oil is detected.

  FIG. 2 shows an embodiment of the above-described signal processing apparatus 10, which drives the liquid level gauge 1 with a density detection function, that is, oscillates an elastic wave from the upper end to the lower end of the magnetostrictive line in the stem, Distance detection means 11 for receiving the reflected waves from 4a, 5a and 6a of each of the floats 4, 5 and 6 by a coil or a piezoelectric vibrator and detecting the distance from the reference position of each of the floats 4, 5 and 6; The density calculation means 12 for detecting the current density of the fuel oil from the distance L1 between 5 and 6 and the density measured by the correction data prepared in the dictionary format or prepared by the empirical formula, for example, the liquid level gauge 1 The reference temperature density calculating means 13 that converts the reference temperature, for example, to a density of 15 ° C. based on the temperature of the fuel oil by an oil temperature sensor or the like incorporated in the sensor, and the difference between the reference density and the reference density measured last time is defined Whether it is within the range of If it is within the specified range, it is next determined whether or not it is within the density range specified for the oil type. If each condition is satisfied, the data is updated with the current reference temperature density, and If the above conditions are not satisfied, the density determination updating means 14 for outputting an alarm signal, the oil mixture determination notifying means 15 for receiving an alarm signal from the density determination updating means 14 and notifying by a display, sound and light emitting means, and Is provided.

Further, based on the latest density updated by the density determination updating means 14, data relating to the draft of the float 4 for measuring the liquid level, that is, a draft value calculation for calculating and updating the distance L2 between the draft and the magnetic body 4a. The liquid level from the liquid level calculation means 17 that calculates the liquid level based on the position from the update means 16 and the distance detection means 11 to the magnetic body 4a of the float 4 is corrected based on the updated draft data L2. A liquid level correcting means 18 for calculating a more accurate liquid level H and outputting it to the liquid amount display means 19, and a water detection notifying means 20 for detecting the entry of water from the position of the float 5 to the bottom of the storage tank and making a notification. With.

The operation of the apparatus configured as described above will be described based on the flowchart of FIG.
When unloading is started from the tank truck to the storage tank T (step S1), the liquid level gauge 1 is operated to measure the density of the fuel oil (step S2).

  That is, an elastic wave is oscillated from the upper end of the magnetostriction line, and reflected waves generated by the magnetic bodies 5a and 6a of the water detection float 5 and the density detection 6 are received by the coil or the piezoelectric vibrator, and the floats 5 and 6 are received. A distance L1 between them is detected.

  Needless to say, the distance L1 between the float 5 and the float 6 is proportional to the density of the fuel oil. Therefore, as shown in FIG. 4, a table or the like produced by determining the relationship between the distance L1 and the density by experiments or the like. Is converted into the density of the fuel oil (step S3). Thereby, the density of the fuel oil in the storage tank T can be measured in real time.

By the way, since the density of the fuel oil depends on the liquid temperature, the temperature of the fuel oil is detected by an oil temperature sensor (not shown) incorporated in the liquid level gauge 1 and converted to a reference temperature, for example, a density of 15 ° C. (Step S4).
Data for such temperature correction can be prepared in a dictionary format or as an empirical formula.

Next, as shown in FIG. 5, it is compared with the upper threshold value d + and the lower threshold value d− that define the range of the reference density at the reference temperature set for each oil type (step S5), and enters the threshold value. If it is, it is checked whether the density is within the range between the upper limit value D + and the lower limit value D- defined for the oil type (step S6).
If the density is within the specified density range, the reference temperature density of the density measured this time is updated as the reference density value of the fuel oil in the storage tank T (step S7).

  In step S5, if the upper threshold value d + is higher than the lower threshold value d- or lower than the lower threshold value d−, or if the upper threshold value d + and the lower threshold value d− are within the range, the upper limit value D + and the lower limit value D− are determined in step S6. If it is determined that it is out of range (symbol A in FIG. 5), there is a possibility that different types of fuel oil may be mixed, so an oil mixture alarm is given by a display, sound, and light emitting means (step S8) and necessary. Accordingly, the pump of the fueling device is locked, and the shut valve (not shown) of the storage tank T is closed to forcibly stop the unloading from the tank truck.

  Furthermore, the mixed oil detection signal may be transferred to the centralized monitoring server by using a centralized monitoring system as found in Patent Document 4.

  In this way, when a reasonable density of fuel in the storage tank T is obtained, the distance L2 between the waterline of the liquid level detection float 4 and the magnetic body 4a is corrected to calculate a more accurate liquid level H (step 9) Update data on the water line (step S10).

Thus, during the period when unloading continues (step S11), the above-described operation is repeated, and after the unloading is completed, the above-described density measurement operation is repeated for a predetermined time t1 (step 12). .
Thereby, it can update to the data regarding the density and water line in the state where oil temperature settled to the fixed value.

As shown in FIG. 6, the reference temperature density during refueling to the storage tank T is, for example, when fuel oil having a higher liquid temperature than the fuel oil in the storage tank is supplied from the tank truck, the unloading start time (FIG. 6). The density fluctuates with time from the point A in FIG. When the unloading stops (at time point B in FIG. 6), the liquid temperature gradually changes to the original temperature of the storage tank, so that the density also gradually changes and settles to a constant value after a predetermined time T1.

  On the other hand, since the density of the fuel oil depends on the oil temperature, even if the oil type is the same, it varies with the season in a period of one year even if the oil type is the same. When deviating from the prescribed ranges D + and D−, the oil types are different, that is, another oil type may be mixed.

  In the above-described embodiment, the position of each float is detected by the displacement detection means using the magnetostrictive line in the stem and the magnetic material of the float. However, other position detection means, for example, laser or ultrasonic waves are used. Obviously, the same effect is obtained even if the position of each float is detected.

DESCRIPTION OF SYMBOLS 1 Liquid level gauge 2 Rising pipe 3 Stem 4 Float for liquid level detection 4a Magnetic body 5 Float for water detection 5a Magnetic body 6 Float for density detection 4a-6a
Magnetic body 7 Elastic body 10 Signal processing device

Claims (3)

  A density detection float that is guided by the stem and floats and sinks corresponding to the density of the fuel oil, a water detection float that is guided by the stem and floats and sinks according to the water level, the density detection float, and the water detection float A reference temperature density at a reference temperature by calculating a fuel oil density based on the distance, an elastic body that connects the elastic body, means for detecting the distance between the density detection float and the water detection float, and the distance Reference temperature density calculating means for performing, and density determination updating means for notifying the mixed oil when the density from the reference temperature density calculating means is outside the threshold with respect to the reference temperature density registered for each oil type from the reference temperature density. An oil mixture prevention device for a liquid level measuring device comprising: The density determination updating means converts the reference temperature density from the reference temperature density to the reference temperature density registered for each oil type when the density from the reference temperature density calculation means is within a threshold value. The oil mixture prevention device of the liquid level measuring device according to claim 1, which is updated by density from The liquid level measurement according to claim 2, wherein a liquid level detection float is attached to the stem so that the liquid level of the fuel oil can be detected, and the draft data of the liquid level detection float is updated based on the updated density. Equipment for preventing mixed oil.

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