KR0169747B1 - Absolute pressure detecting sensor and apparatus for detecting the leakage from a vessel using it - Google Patents

Abstract

Provided is a leak condition inspection apparatus for a container that does not take time to measure and can perform a high-precision measurement.

When measuring the leakage state, the tank is filled with an inert gas to a predetermined pressure. The CPU detects the pressure in the tank according to the detection value of the semiconductor sensor and compensates this pressure according to the detection value of the upper or lower temperature sensor that detects the temperature of the upper or lower part in the tank. The CPU stores the internal pressure of the tank after this compensation in the RAM every predetermined time. This stored measurement data is interpreted by the CPU, and it is judged that no leakage occurs if the pressure change within a predetermined time is equal to or less than a certain amount.

Description

Absolute pressure sensor and leak tester of container using the sensor

1 is a schematic configuration diagram of an absolute pressure detection sensor of the present invention.

FIG. 2 is a diagram showing a partial configuration of a semiconductor sensor in the sensor shown in FIG.

3 is a schematic configuration diagram of a tank raleigh generally used.

4 is an explanatory view of a measuring operation of the leak state inspection apparatus of the container according to the present invention.

5 is an external view of the sensor portion of the leak state inspection apparatus of the container according to the present invention.

6 is an external view of the recording computing device in the leak state inspection apparatus of the container according to the present invention.

7 is a block diagram showing the configuration of the control system of the leak state inspection apparatus according to the present invention.

8 is an operation flowchart showing the measurement processing of the apparatus shown in FIG.

FIG. 9 is an operation flowchart showing data processing of the apparatus shown in FIG.

* Explanation of symbols for main parts of the drawings

10 pressure sensor 14 partition wall

16: 1st room 18: 2nd room

22 semiconductor sensor 30 silicon wafer

32A, 32B: Distortion Sensor 40: Tank Raleigh

52: measuring instrument 61: sensor unit

63: container 68,69: temperature sensor

80: recorder 85: pressure detection sensor

100: CPU 102: RAM

The present invention relates to an absolute pressure detecting sensor capable of detecting the absolute pressure of a container to be measured with high accuracy and a leak state detecting device for detecting a leak state of the container using the absolute pressure detecting sensor. In particular, the present invention relates to a leak condition inspection apparatus suitable for detecting a tank leak of a tank lorry.

Conventionally, petroleum products such as gasoline, diesel, kerosene and heavy oil, liquefied gas such as LPG and liquid oxygen, chemicals such as hydrochloric acid, sulfuric acid and alcohol, molasses and foods such as milk, olive oil, coconut oil, tallow and whale oil, etc. Tank Raleigh is widely used for the land transportation of animal and vegetable oil, water supply and water for spraying.

Many of these loads are subject to the Fire Act, the Poisonous Control Act, the High Pressure Gas Control Act, the Food Sanitation Act, etc., and therefore, the structure and airtightness of the tank are extremely strict to ensure safety during transportation.

For this airtightness, for example, a pressure test of 0.7 kg / cm < 2 > other than the pressure tank and a pressure test of 1.5 times the maximum normal pressure in the pressure tank are performed for 10 minutes, respectively, to prevent leakage or deformation.

One method of testing this airtightness is the hydrostatic test, in which water is filled in a tank and its leak is examined. According to this hydraulic test method, first, after discharging all the contents contained in the tank, filling the tank with water, and then pressurizing the inside of the tank with a pump to a pressure of 0.2kg / cm 2 to 0.7kg / cm 2 and leaving it alone for 60 minutes. The treatment is carried out before the measurement.

If the pressure in the tank measured after 10 minutes from the stand-by point and the pressure difference measured after 60 minutes remain at 10% or less of the pressurized pressure, it is determined that the airtight state is not abnormal. Thereafter, the water in the tank is completely removed to carry out the treatment.

However, in such a conventional hydraulic test method, it is necessary to fill the tank with water at the time of the test, which takes a long time. That is, in the case of tank Raleigh dedicated to transporting gasoline, it is necessary to remove the gasoline before the test and fill it with water, and to completely remove the water after the measurement, and to transport the gasoline immediately after the test. This does not apply to feed water tank rolls, but it can be said that it takes about 1 day for this test because tank rolls used for normal transportation are mostly other than feed water.

In addition, since the Bourdon tube pressure gauge etc. are normally used for this measurement, a high precision measurement is impossible, and since it is a meter of the reading method using a dial normally, a reading error always exists and there is no problem also in the reliability of the measurement data. Could not.

Since the detection of the leaked state by a very small hole is practically impossible, there is a current demand for a high-precision measuring device capable of detecting the leaked state even when the leak is very small.

SUMMARY OF THE INVENTION The present invention has been made in accordance with such conventional problems and demands, and its first object is to provide an absolute pressure detection sensor capable of detecting absolute pressure with high accuracy, and a second object is to provide high accuracy without taking time for measurement. It is to provide a leak state inspection apparatus of a container using this absolute pressure sensor that can measure the.

The absolute pressure detection sensor of the present invention for achieving the first object is a first chamber which is blocked from the outside in an open casing and maintained at a constant pressure and the first chamber communicates with the outside to exhibit the same pressure as the external pressure. The partition wall is formed so that two chambers are formed, and the partition wall is configured to be freely deformed according to the pressure difference between the pressure of the first chamber and the pressure of the second chamber, and outputs an electrical signal according to the deformation amount to the partition wall. It is characterized in that the pressure detecting means is installed.

In addition, the pressure detecting means is characterized in that the semiconductor distortion sensor whose resistance value changes in accordance with the deformation amount of the partition wall, and a resistor that always shows a constant resistance value in spite of the deformation amount are alternately electrically bridged.

In addition, the leak state inspection apparatus of the container of the present invention for achieving the second object is a sealing means for making the container to be inspected in which the contents are contained in a completely airtight state, the inert gas in the container sealed by the sealing means Gas pressure means for pressurizing and charging the gas to a predetermined pressure, an absolute pressure sensor for detecting gas pressure in the inspected container pressurized and charged by the gas filling means, and a gas pressure for each predetermined time detected by the absolute pressure detection sensor. And memory means for storing.

In addition, a sealing means for making the container to be inspected completely sealed while the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and the gas filling means. Absolute pressure detecting sensor for detecting the gas pressure in the test container which is pressurized and charged by the gas, storage means for storing the gas pressure for each predetermined time detected by the absolute pressure detecting sensor, and the gas pressure stored in the storage means over time. And determining means for determining a leak state of the inspected container according to the change.

And sealing means for completely sealing the inspected container in a state where the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and the gas filling means. The absolute pressure detecting sensor for detecting the gas pressure in the inspected container which is pressurized and charged by the temperature, the temperature detecting means for detecting the temperature in the inspected container, and the gas pressure detected by the absolute pressure detecting sensor by the temperature detecting means. And a temperature compensating means for performing temperature compensation in accordance with the set temperature, and a storage means for storing the gas pressure after temperature compensation by said temperature compensating means.

In addition, a sealing means for completely sealing the inspection object in a state where the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and the gas filling means. The absolute pressure detecting sensor for detecting the gas pressure in the inspected container which is pressurized and charged by the temperature, the temperature detecting means for detecting the temperature in the inspected container, and the gas pressure detected by the absolute pressure detecting sensor by the temperature detecting means. A temperature compensating means for temperature compensation according to the set temperature, a storage means for storing the gas pressure after temperature compensation by said temperature compensating means, and a leakage state of said inspected container in accordance with the change of the gas pressure stored in said storage means over time. It is characterized by having a judging means for judging.

The absolute pressure detection sensor according to the present invention operates as follows.

The absolute pressure detection sensor is provided with a partition wall so that a first chamber which is blocked from the outside and maintained at a constant pressure in a casing in which one side is opened and a second chamber which communicates with the outside and exhibits the same pressure as the external pressure are formed. Since the structure is configured to be freely deformed according to the pressure difference between the pressure of the first chamber and the pressure of the second chamber, the partition wall is deformed according to the pressure difference between the external pressure and the pressure in the first chamber. The pressure detecting means outputs an electric signal in accordance with the degree of this deformation. Therefore, it is possible to detect the external absolute pressure in accordance with the level of the electrical signal.

Specifically, the pressure detecting means is composed of a semiconductor distortion sensor whose resistance value changes depending on the deformation amount of the partition wall, and a resistor which always shows a constant resistance value regardless of the deformation amount, is electrically bridged alternately. Is the unbalanced voltage of the bridge circuit unbalanced according to the deformation state of the partition wall.

In addition, the leak state inspection apparatus of the container according to the present invention operates as follows approximately.

The sealing means keeps the container under test completely in a state where the contents are accommodated. The gas filling means pressurizes and fills the container sealed by this sealing means to a predetermined pressure. The absolute pressure detection sensor detects the gas pressure in the inspection container pressurized and filled by this gas filling means, and the storage means stores the gas pressure for each predetermined time detected by the absolute pressure detection sensor.

Then, the judging means judges the leakage state of the inspected container in accordance with the change of the gas pressure stored in the storage means over time.

In addition, taking into account that the pressure in the tank changes with the temperature change during the measurement, in order to compensate for the influence of the temperature change, a temperature detecting means for detecting the temperature in the container to be inspected is provided. In this case, the temperature compensating means performs temperature compensation on the gas pressure detected by the absolute pressure detecting sensor in accordance with the temperature detected by this temperature detecting means, and the gas pressure after temperature compensation by this temperature compensating means is stored in the storage means. Then, the judging means judges the leakage state of the inspected container according to the change of the gas pressure stored in the storage means over time.

Hereinafter, an embodiment of a leak state inspection apparatus of a container according to the present invention will be described in detail with reference to the drawings.

1 shows a configuration of an absolute pressure detection sensor according to the present invention. This absolute pressure detection sensor 10 can detect the external absolute pressure with high accuracy.

The cross section of this absolute pressure detection sensor 10 is shown in FIG. 1A.

The pressure detection sensor 10 is formed by two partition walls 14 in the case 12. Among these two rooms, the first chamber 16 which is completely isolated from the outside by the partition 14 is formed using a coating material for the closing member 18 constituting one end surface of the case 12 in the air. It is formed by sealing as shown in the figure. In this way, the pressure of the first chamber 16 is always maintained at the atmospheric pressure after sealing. Another room formed by the partition wall 14 and the case 12, that is, the second chamber 18 is a room for introducing atmospheric pressure through an open hole. The pressure in the tank of the tank Raleigh is introduced via 20).

The partition 14 is attached with a semiconductor sensor 22 that enables high-precision pressure measurement. This semiconductor sensor 22 is composed of a distortion sensor and a fixed resistor manufactured by double diffusion on a silicon wafer. This semiconductor sensor 22 is comprised so that the extremely small distortion can be taken out as an electrical signal. In addition, although the distance of the partition 14 and the case 12 of the pressure introduction pipe side is exaggerated and enlarged in the same figure, it is actually a fine distance of about 0.15 mm. The semiconductor sensor 22 is connected to a stem electrode 24 fixed in an insulated state from the case 12 via a platinum lead wire, and the electrode 24 is connected to an external computer or the like.

1B is a view of the absolute pressure detecting sensor 10 viewed from the attachment direction of the stem electrode 24. In this figure, six stem electrodes are attached. However, in general, six stem electrodes are used to extract signals from four stem electrodes, and in case of special use, six stem electrodes are used.

2 is a diagram illustrating a detailed configuration of the semiconductor sensor 22.

Distortion sensors 32A and 32B and fixed resistors 34A and 34B are formed as shown on the silicon wafer 30 by double diffusion, and the adjacent distortion sensors 32A and fixed resistors are respectively formed. 34A, the distortion sensor 32B, and the fixed resistor 34B are bridged by connecting lines 35A, 35B, 35C, and 35D. Although not shown, each of these connecting lines 35A, 35B, 35C, and 35D is connected to each of the stem electrodes 24 shown in FIG.

The silicon wafer 30 constitutes the partition 14 and deforms according to the pressure difference between the first chamber 16 and the second chamber 18. The deformation value of the distortion sensor 32A and the distortion sensor 32B varies depending on the deformation of the silicon wafer 30, and the distortion sensor 32A, the fixed resistor 34A, the distortion sensor 32B, and the fixed resistor 34B The equilibrium state of the bridge composed of) is broken, and the voltage according to the deformation amount appears on the stem electrode 24. The computer or the like connected to the stem electrode 24 detects the pressure with high accuracy according to this voltage.

In addition, this pressure detection sensor 10 is for measuring absolute pressure. When the first chamber 16 is formed as described above, when the level of the electric signal output from the semiconductor sensor 22 is stored as an initial pressure in the microcomputer, the absolute value is detected by detecting the difference between the reference values. The pressure can be detected. In this way, it becomes extremely easy to design and manufacture a sensor, and it becomes possible to realize the sensor which can measure a high precision at low cost.

3 is a schematic configuration diagram of a tank rolley in which a leak condition is inspected by the above-described absolute pressure detection sensor. 4 is explanatory drawing at the time of attaching the leak state inspection apparatus of a container using this absolute pressure sensor to this tank roller.

The tank of the tank rolly 40 is partitioned into a plurality of rooms (hereinafter, each room is referred to as a tank independently) by a plurality of partition plates 42 provided therein, and accommodated in each tank. The breakwater plate 44 is provided so that the fluctuation | variation of a liquid etc. may be reduced. A manhole 46 is attached to the upper portion of each tank formed by the partition plate 42, and when the load is accommodated in the tank, the injection hole 48 formed in the manhole is opened. The manhole 46 is provided with a safety valve 50 which prevents pressure breakdown of the tank when the pressure of the tank becomes higher than specified. In addition, the measuring hole 52 is also provided in the manhole 46, and the measuring hole 52 is used when the measuring rod 54 is fitted to measure the flow rate of each tank. In the apparatus of the present invention, the measuring tool 52 is used for measurement.

The apparatus of the present invention is attached to the metering opening 52 provided in the manhole 46 of the tank rolly 40 as shown in FIG. The plug 60 is first inserted into the metering port 52. And the screw formed in the plug 60 and the screw formed in the measurement port 52 are matched. Next, the screw provided in the sensor part 61 which becomes a main part of this invention is attached by engaging with the screw formed in the plug 60, and the metering opening 52 is made to be fully sealed. Since the plug 60 is provided with an open valve 62 with a one-touch socket, it cannot be completely sealed as it is. However, the open valve 62 has a container 63 filled with nitrogen gas; A bomb is attached via the hose 64. In this state, the tank as the container to be inspected having the manhole 46 is completely shut off from the outside.

In addition, although nitrogen gas is illustrated as an inert gas in a present Example, of course, it is not limited to this. The pressure reducing valve 65 and the safety valve 66 are installed in the hose 64 communicating the container 63 and the opening valve 62, which raises the tank to a predetermined pressure and prevents an accident in case of abnormality. will be. After the measurement is completed, the opening plug 67 is attached to the opening valve 62 instead of the hog 64, so that the nitrogen gas charged in the tank is released to the atmosphere with low noise.

In the above structure, the sealing means is comprised by the metering opening 52, the plug 60, the sensor part 61, and the opening valve 62, and the container 63, the hose 64, and the pressure reduction valve ( 65), the gas filling means is constituted by the safety valve 66.

The sensor 61 which functions as an absolute pressure detection sensor is provided with a sensor or a microcomputer necessary for the measurement. The sensor unit 61 is provided with two temperature sensors 68 and 69 which are connected to the outside via a lead wire. Here, the temperature sensor positioned at the top of the tank when the sensor unit 61 is mounted among these temperature sensors is referred to as the upper temperature sensor 68, and the temperature sensor positioned below the lower temperature sensor 69. These temperature sensors 68 and 69 function as temperature detection means. On the upper surface of the sensor unit 61, as shown in FIGS. 4 and 5, a power switch 70, a connector 71 for outputting the accumulated measurement data to an external device, a measurement temperature display unit 72 and Measuring pressure display sections 73 are provided, respectively.

In the present embodiment, since the two temperature sensors are provided, the measurement temperature display unit 72 displays each measurement temperature. In addition, a high-precision pressure sensor for detecting the pressure in the tank is inserted inside the sensor unit 61 via a plug 60. The pressure in the tank after temperature compensation is measured according to the detected value from the pressure sensor or the temperature sensor. The microcomputer which calculates and stores the value after association with every predetermined time is also built in.

As an example of the external device connected to the connector 71 of the sensor part 61 as needed, the recorder shown in FIG. 6 is mentioned. The recorder 80 reads out measurement data stored in the microcomputer of the sensor unit 61, and displays or prints out the display unit 81 as necessary. This readout, printout, or the like is commanded by the keys arranged on the operation unit 82. In addition, the recorder 80 does not need to be connected during the measurement of the internal pressure of the tank by the sensor unit 61. After the measurement is finished, the recorder 80 transfers the measurement data stored in the microcomputer and then measures the measurement data only by the recorder. It is to be interpreted.

7 is a block diagram of a control system for detecting a leakage state according to the present invention.

In the figure, the semiconductor sensor 22 measures the pressure change in the tank, and the upper temperature sensor 68 and the lower temperature sensor 69 measure the upper and lower temperatures in the tank, respectively. The CPU 100 processes the detected data detected from each of the sensors according to a program stored in advance or stores it in the RAM 102 as it is. The recorder 80 connects to the connector 71 provided in the sensor part 61 as needed, reads out measurement data stored in the RAM 102, and prints out or displays the data. In addition, by operating the keys provided therein, necessary statistical processing and printout of the data can also be performed.

The leak state inspection apparatus of the container in this invention comprised as mentioned above operates as follows according to the flowchart of FIG. 8 and FIG.

The flowchart shown in FIG. 8 is a flowchart processed when pressure measurement is performed. As a premise in which this measurement is performed, the sensor part 61 is attached to the metering opening 52 of the tank rolly, and it is assumed that nitrogen gas is enclosed in the tank at the predetermined pressure. When the measurement start command is output in this state, the CPU 100 and all elements and sensors connected thereto are initialized (S1), and the CPU 100 inputs the pressure in the tank detected by the semiconductor sensor 22. (S2) and at the same time input the temperature detected by the upper temperature sensor 68 and the lower temperature sensor 69 (S2, S3), and these input values are stored in the RAM 102 once.

Next, the CPU 100 calculates a pressure detection value detected by the semiconductor sensor according to the temperatures detected by the two temperature sensors (S5), and the value after this correction processing is stored in the RAM 102 (S6). ). The storage processing of the measurement data described above is performed every predetermined data collection time, and the collection of this data is performed until the measurement time ends (S7, S8). In the above embodiment, the measurement time in the step S7 is 60 minutes, and the data collection time of S8 is every 5 minutes from the start of measurement. Therefore, in the actual device, 12 points of measurement data are obtained.

Next, the flowchart shown in FIG. 9 relates to the operation of the recorder 80.

When the recorder 80 is connected to the connector 71 of the sensor unit 61 and a command for transferring data stored in the RAM 102 is outputted, the CPU built in the CPU 100 and the recorder 80 is output. By this, the measurement data stored in the RAM 102 is transferred to the recorder 80 (S11). Next, this transferred data is analyzed in accordance with the operation of the various keys provided in the recorder 80 (S12), and if there is a print command, the analysis result is printed out according to the command (S13, S14). Specifically, the analysis results are the detection pressure, the detection temperature and the pressure fluctuation (after temperature compensation) in each time series, and the measurement result.

As described above, according to the leak state inspection apparatus of the container of the present invention, since the operation of removing the contents of the tank once and filling the water is not necessary at all, the measurement operation is very simple, and the measurement may be almost completely automatic. Since the analysis and the like are automatically performed by a computer, measurement errors are not generated. In particular, temperature compensation is also performed so that the reliability of the measurement data is very high. In addition, since the measurement data obtained are digital data, it is easy to store and becomes extremely useful basic data for later data analysis and the like.

As described above, according to the apparatus of the present invention, the inert gas is filled into the inspected container, and the leak state of the container is detected according to the change of gas pressure in the container over time. You can do it quickly.

Moreover, since the absolute pressure detection sensor of the structure which can measure a high precision is used for the measurement, high accuracy can be measured and the reliability of a leak state determination improves.

Claims (6)

A partition wall is arranged to form a first chamber, which is blocked from the outside and maintained at a constant pressure in an open casing on one side, and a second chamber communicating with the outside and exhibiting the same pressure as the external pressure, wherein the partition wall is formed in the first chamber. And a pressure detecting means for outputting an electrical signal according to the deformation amount, the barrier rib being freely deformed according to the pressure difference between the pressure of the second chamber and the pressure of the second chamber. The said pressure detecting means is comprised by the semiconductor distortion sensor whose resistance value changes with the deformation amount of the said partition, and the resistor which always shows a constant resistance value irrespective of the said deformation amount, and is electrically bridge-connected alternately. Absolute pressure detection sensor, characterized in that. Sealing means for making the container to be inspected in a completely sealed state with the contents contained therein; gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means; And an absolute pressure detecting sensor for detecting the gas pressure in the test container filled with pressure, and a storage means for storing the gas pressure for each predetermined time detected by the absolute pressure detecting sensor. A sealing means for keeping the container under test completely sealed while the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and by the gas filling means. Absolute pressure detection sensor for detecting the gas pressure in the pressurized container to be charged, the storage means for storing the gas pressure for each predetermined time detected by the absolute pressure detection sensor, and the change over time of the gas pressure stored in the storage means And a judging means for judging the leakage state of the inspected container according to the present invention. A sealing means for keeping the container under test completely sealed while the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and by the gas filling means. An absolute pressure detecting sensor for detecting a gas pressure in the test container filled with pressure, a temperature detecting means for detecting a temperature in the test container, and a gas pressure detected by the absolute pressure detecting sensor for the temperature detected by the temperature detecting means. And a temperature compensating means for compensating the temperature according to the temperature, and a storage means for storing the gas pressure after the temperature compensation is performed by the temperature compensating means. Sealing means for making the container under test completely sealed while the contents are accommodated, gas filling means for pressurizing and filling an inert gas to a predetermined pressure in a container sealed by the sealing means, and by the gas filling means. An absolute pressure detecting sensor for detecting a gas pressure in the test container filled with pressure, a temperature detecting means for detecting a temperature in the inspected container, a gas pressure detected by the absolute pressure detecting sensor, and a temperature detected by the temperature detecting means. A temperature compensating means for temperature compensation in accordance with the present invention, a memory means for storing gas pressure after temperature compensation by the temperature compensating means, and a leak state of the container to be inspected according to the change of the gas pressure stored in the storage means over time. Leakage state inspection apparatus of the container, characterized in that it has a determining means.