JP2006113030A - Air bubble type liquid level gage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manifold so as to decrease an installation man day in an air bubble type liquid level gage using a plurality of electromagnetic valves. <P>SOLUTION: The liquid level gage comprises a compressed air supply source 34 providing an compressed air to a feed tube 12 submerged in a liquid 14, a pressure sensor 54 measuring an air pressure inside the feed tube 12, a first electromagnetic valve 65 which opens and closes at a compressed air supply path to the feed tube 12, and a second electromagnetic valve 66 which opens and closes an air pressure detection path to the pressure sensor 54. The manifold mounting the electromagnetic valves 65, 66 consists of a main manifold 63 having an air supply flow path 68 connected to the compressed air supply source and a sub-manifold 64. An air inlet flow side of the first electromagnetic valve is connected to the air supply flow path 68 of the main manifold 63 via the sub-manifold 64. The sub-manifold 64 consists of the air path connected in series the inlet flow side and the outlet flow side of each electromagnetic valve, the air path connected mutually to the compressed air supply path, and the air path connected mutually to the air pressure detection path. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bubble type liquid level gauge for measuring the level of a liquid level stored in a tank of a ship or the like.

  Level gauges for detecting the level of stored liquid are installed in ballast tanks, oil tanks, water tanks and the like in ships such as container ships and tankers. As a measurement method of such a liquid level gauge, a float type, a bubble type and the like are conventionally known. Many of the conventional bubble level gauges are provided with a supply pipe for each of a plurality of tanks, and the above supply pipe submerged in the liquid stored in the tank is made by a compressor in a machine room or other section. The compressed air is delivered through piping.

  In the bubble-type liquid level gauge, an air supply pipe consisting of a pipe whose lower end is a free opening is arranged vertically in a tank that contains liquid, and when the liquid is in the tank, the lower end of the air supply pipe Compressed air is supplied to the air supply pipe through the pipe so as to be discharged as bubbles. The internal pressure P of the air supply pipe at that time is equal to the head ρH obtained by multiplying the liquid depth H by the liquid density ρ and the gas pressure above the liquid, that is, “total pressure”. The pressure minus the gas pressure above the liquid is displayed on the indicator as the liquid level. Compressed air is created by the compressor in the engine room or other compartments, and is supplied from the main pipe laid on the deck via branch pipes to the level gauge of each tank, or through an independent pipe to detect the level of each tank To be supplied to the department.

  The pressure in the air supply pipe composed of pipes varies depending on the liquid head (liquid depth), and the liquid head varies from one tank to another. However, since the conventional bubble level gauge is supplied with compressed air from a single compressor, the pressure of the compressed air must be kept at the maximum pressure that matches the maximum liquid head to be measured. In some cases, the atmospheric pressure was too high for the liquid head at that time, and the measured value slightly changed.

  Therefore, the applicant of the present invention is to provide an air supply pipe that is immersed in the liquid in the tank, a pump that can supply compressed gas into the air supply pipe, a check valve that is provided between the pump and the air supply pipe, A pneumatic level gauge comprising a pressure sensor for measuring atmospheric pressure and a control means for controlling the pump based on pressure data sent from the pressure sensor, wherein the air supply pipe, the pump, the check valve, and the pressure sensor However, the patent right was acquired regarding the atmospheric | air pressure type liquid level gauge characterized by being provided for every tank (refer patent document 1). The “atmospheric pressure level gauge” referred to in Patent Document 1 is a “bubble level gauge”.

According to the invention described in Patent Document 1,
1. Complicated piping is not required, and it can be easily handled as an electric device that operates independently.
2. Since it is sufficient to have compressed gas sufficient to fill the air supply pipe of the measurement unit, it is sufficient to install a small capacity pump.
3. Since compressed gas is supplied from a close distance of the measurement unit, there is almost no influence of external temperature.
4). Since compressed gas is supplied from a close distance of the measuring unit, simple control is sufficient, and the measuring unit is housed in the detection unit terminal box, so that maintenance and inspection are simple.
Such an effect can be obtained.

Japanese Patent No. 2995154

  Recently, in order to save money by simplifying the liquid level gauge, it is an explosion-proof section of a tanker, chemical ship, or LNG ship. However, it has come to be used in tanks that do not require so high measurement accuracy.

  Therefore, an example of a recent bubble type liquid level gauge will be described. 5 and 6, a liquid 14 such as oil or water is stored in the tank 10 of the ship. An air purge head 20 is attached to the upper surface of the ceiling of the tank 10 via a stand piece 16, and an air supply pipe 12 is attached from the air purge head 20 toward the bottom surface of the tank 10 in a suspended manner. A pipe 30 and a pipe 32 are connected to the air purge head 20. The pipe 30 is a pipe for supplying compressed air, and the pipe 32 is a pipe for taking out signal air.

  As shown in FIG. 6, the air purge head 20 has a shape in which a cup is turned upside down, and the inside thereof is divided into two vertically by a partition wall 21, and a diaphragm 22 is attached to the partition wall 21. The upper room divided by the partition wall 21 communicates with the pipe 30 through a pipe. The pipe 30 also communicates with the air supply pipe 12 through the orifice 26 and through the flow control valve 28. The air supply pipe 12 communicates with the pipe 32 through a flow rate control valve 28 and a pipe. The air supply pipe 12 also communicates with the internal space of the diaphragm 22 through an appropriate pipe. Therefore, the air pressure inside the diaphragm 22 and the air pressure inside the air supply pipe 12 are the same. A coiled spring 24 is disposed inside the diaphragm 22, and biases the diaphragm 22 upward in FIG. 6, and therefore, in a direction to narrow the upper space defined by the partition wall 21. The flow control valve 28 is integrally connected to a rod hanging from the ceiling of the diaphragm 22.

  The air purge head 20 operates as follows. When compressed air is supplied from the pipe 30 with the lower end portion of the air supply pipe 12 submerged in the liquid 14 in the tank 10, the air pressure in the upper space, that is, the air pressure outside the diaphragm 22 is changed to the air pressure inside the diaphragm 22. That is, the pressure in the air supply pipe 12 becomes higher, and the diaphragm 22 is compressed against the elasticity of the spring 24. By the operation of the diaphragm 22, the flow rate control valve 28 is pushed down to open the valve, and compressed air is supplied into the supply pipe 12 through the orifice 26 at a constant flow rate. The liquid level in the air supply pipe 12 is pushed down by this compressed air, and then the compressed air is released from the lower end of the air supply pipe 12, rises as a bubble in the liquid 14, and is released into the atmosphere. Since the air pressure in the air supply pipe 12 increases as the level of the liquid 14 in the air supply pipe 12 decreases, the level of the liquid 14 can be measured by measuring the air pressure in the air supply pipe 12. At the beginning of supplying compressed air to the air supply pipe 12, the flow rate control valve 28 is largely pushed down to increase the flow rate of the compressed air, and the opening amount of the flow rate control valve 28 decreases as the liquid level in the air supply pipe 12 is pushed down. As a result, the flow rate decreases. When bubbles are released and the liquid level is measured, compressed air is released from the lower end of the supply pipe 12 by a certain amount. Thus, the air purge head 20 constitutes a constant flow rate mechanism.

In FIG. 5, compressed air is supplied from the compressor 34 to the pipe 30. An inboard regulator 36 and an air supply unit 40 are interposed between the compressor 34 and the pipe 30. The inboard regulator 36 adjusts the pressure of the compressed air sent out from the compressor 34 to, for example, about 7 kg / cm ² . The air supply unit 40 is disposed in the control room 38, and has a stop valve 42, a filter 44, a regulator 46, and a pressure gauge 48 in order from the compressor 34 side. In the control room 38, a switching valve 50, an aeroelectric converter 52, and an indicator 58 are arranged. The aeroelectric converter 52 detects air pressure and converts it into an electrical signal, and includes a pressure sensor 54 and a control board 56 that controls the pressure indication value by the indicator 58 according to the output of the pressure sensor 54. . As shown in the figure, the switching valve 50 guides the atmospheric pressure in the supply pipe 12 to the aeroelectric converter 52, and rotates the air pressure applied to the aeroelectric converter 52 by rotating 90 degrees clockwise from the illustrated state. It is possible to switch to a zero correction mode that opens to the atmosphere.

  When the switching valve 50 is in the switching mode shown in FIG. 5, the atmospheric pressure in the air supply pipe 12 is applied to the pressure sensor 54. This atmospheric pressure depends on the level of the liquid 14 stored in the tank 10 as described above. The pressure sensor 54 outputs an electrical signal corresponding to the atmospheric pressure applied thereto. The electrical signal is processed on the control board 56 to display the liquid level by the indicator 58, and the indicator 58 displays the liquid level.

  According to the conventional bubble-type liquid level gauge described above, it has an air purge head equipped with a diaphragm, a spring, and a flow rate control valve in order to supply a constant amount of compressed air to the air supply pipe. There are drawbacks that are easy to break down and costly. In addition, since it is necessary to constantly supply compressed air from the compressed air supply source to the air supply pipe, the amount of compressed air consumption increases, and in addition, there is pulsation due to the release of compressed air, which is transmitted to the pressure sensor and displayed. There is a difficulty that the value fluctuates and becomes unstable.

  Therefore, the present inventor has invented a bubble type liquid level gauge devised so that the air purge head used in the conventional bubble type liquid level gauge is unnecessary, the structure is simple, there are few failures, and the cost is reduced. The example shown in FIGS. 7 and 8 is a first electromagnetic valve that opens and closes the compressed air supply path from the compressed air supply source to the supply pipe, and a second electromagnetic valve that opens and closes the atmospheric pressure detection path from the supply pipe to the pressure sensor. In the supply mode in which the first electromagnetic valve opens the compressed air supply path, the second electromagnetic valve closes the atmospheric pressure detection path, and the second electromagnetic valve opens the atmospheric pressure detection path in the measurement mode. The opening / closing operation of each electromagnetic valve is controlled by software so that the electromagnetic valve closes the compressed air supply path. Hereinafter, examples shown in FIGS. 7 and 8 will be described.

  In FIG. 7, a pipe 30 is connected via a stand piece 16 and a flange 60 to a ceiling upper surface side of a tank 10 such as a tanker in which a liquid 14 such as oil or water is stored. Unlike the above-described conventional example, an air purge head is not provided, but a check valve may be provided here if necessary. The pipe 30 is, for example, a pipe on a ship deck, and the pipe 30 also functions as a compressed air supply pipe by opening and closing control of the first and second electromagnetic valves 65 and 66, It also functions as piping for taking out. An air supply pipe 12 is attached to the stand piece 16 so as to hang down toward the bottom surface of the tank 10, and the air supply pipe 12 is immersed in the liquid 14 in the tank 10 from its lower end.

  In addition to the first and second electromagnetic valves 65, 66, there is a third electromagnetic valve 67. These three electromagnetic valves 65, 66, 67 are arranged close to each other and connected in series by piping. ing. The operation of each electromagnetic valve is controlled by a control board 56 that the aeroelectric converter 52 has. Each solenoid valve moves in one direction when the drive coil is excited to connect the air inflow side and the outlet side, and when the drive coil is not excited, it moves with an urging force to move the air inflow side and the outlet side. It is configured to block the side. The air inflow side of the first electromagnetic valve 65 is connected to the piping from the air supply unit 40. The piping connecting the electromagnetic valves 65 and 66 is branched and connected to the piping 30, and the piping connecting the electromagnetic valves 66 and 67 is branched and connected to the piping reaching the pressure sensor 54. In addition, the air outlet side of the third electromagnetic valve 67 is connected to a pipe for opening to the atmosphere.

  As in the conventional example, the compressor 34 is a compressed air supply source, and an inboard regulator 36 and an air supply unit 40 are interposed between the compressor 34 and the first electromagnetic valve 65. The inboard regulator 36 adjusts the pressure of the compressed air sent out from the compressor 34 to an appropriate pressure. The air supply unit 40 includes a stop valve 42, a filter 44, a regulator 46, and a pressure gauge 48 in order from the compressor 34 side. A control board for controlling an atmospheric pressure indication value by an indicator (not shown) according to the output of the pressure sensor 54 is provided. This control board has a calculation function for calculating the detection output of the pressure sensor 54 and converting it to the liquid level in the tank 10 and displaying the liquid level on the indicator. Also installed on the control board is software for controlling the opening and closing operations of the electromagnetic valves 65, 66, and 67.

  Next, the operation of the bubble type liquid level gauge will be described. There are three operation modes, that is, an air supply mode, an air stop mode, and a measured pressure atmospheric discharge mode, depending on the opening / closing operation modes of the three electromagnetic valves 65, 66, and 67. The “air supply mode” is a mode in which compressed air is supplied from the compressed air supply source to the air supply pipe 12, that is, “air supply mode”, and the “air stop mode” is a liquid level level by stopping air supply. This is a mode for measuring, ie, “measurement mode”. The “measured pressure atmospheric release mode” is an operation mode for performing zero point adjustment in which the compressed air applied to the pressure sensor is opened to the atmosphere to be atmospheric pressure, and the indicated value of the indicator at this time is zero. In FIG. 7, SV 1 indicates the first electromagnetic valve 65, SV 2 indicates the second electromagnetic valve 66, and SV 3 indicates the third electromagnetic valve 67.

  In the “air supply mode”, the first electromagnetic valve 65 opens the compressed air supply path, the second electromagnetic valve 66 closes the atmospheric pressure detection path connected to the pressure sensor 54, and compressed air is supplied to the air supply pipe 12. In the “air stop mode”, the first electromagnetic valve 65 closes the compressed air supply path, only the second electromagnetic valve 66 opens to open the atmospheric pressure detection path, and the atmospheric pressure in the supply pipe 12 is the pressure sensor 54. To take on. In the “measured pressure atmospheric release mode”, only the third electromagnetic valve 67 opens and the pressure applied to the pressure sensor 54 is the same as the atmospheric pressure.

  The “supply mode” in which only the first electromagnetic valve is opened and the “measurement mode” in which only the second electromagnetic valve is opened are controlled to be switched alternately and intermittently. Until the start of the air supply mode, the liquid level in the air supply pipe 12 is at the same level as the liquid level of the liquid 14 stored in the tank 10, and the air pressure in the air supply pipe 12 by executing the air supply mode. Rises and the level of the liquid level in the supply pipe 12 falls. Since the air supply mode and the measurement mode are executed alternately, the air pressure in the air supply pipe 12 rises stepwise at the beginning of the air supply. When the air pressure in the air supply pipe 12 rises and the liquid level in the air supply pipe 12 reaches the lower end of the air supply pipe 12, the compressed air leaks from the lower end of the air supply pipe 12 and bubbles in the liquid 14 in the tank 10. It rises and is released to the atmosphere. Accordingly, the air pressure in the air supply pipe 12 becomes an air pressure corresponding to the level (depth) of the liquid 14 in the tank 10, and the air pressure in the air supply pipe 12 does not change unless the level of the liquid 14 changes. Therefore, when the measurement value no longer fluctuates in the measurement mode, the detection output of the pressure sensor 54 is converted into a liquid level, and this is read with an indicator (not shown) to measure the level of the liquid level 14 at that time. be able to.

  Next, an example shown in FIG. 8 will be described. In this example, piping is added to the example shown in FIG. That is, the compressed air outlet side port A1 of the first electromagnetic valve 65 is connected to the air supply pipe 12 via the compressed air supply path 30, and the air inlet side port P2 of the second electromagnetic valve 66 is connected via the atmospheric pressure detection path 32. It is connected to the supply pipe 12. In the example shown in FIG. 7, the first and second electromagnetic valves 65 and 66 are directly connected, and the middle of them is branched and connected to the air supply pipe 12 by one pipe, whereas in the example shown in FIG. As described above, the first and second electromagnetic valves 65 and 66 are separated from each other and connected to the supply pipe 12 via the compressed air supply path 30 and the atmospheric pressure detection path 32, respectively. Other than that, the configuration is the same as that of the example shown in FIG.

  In the example shown in FIG. 7, the pipe 30 has a function as a compressed air supply path to the air supply pipe 12 and a function as a pipe for taking out signal air, and these functions are alternately and repeatedly switched. At each switching, an air flow is generated in the pipe 30 to generate a pressure loss ΔP. After switching to a function as a pipe for taking out signal air, the supply pipe is not supplied until the time corresponding to the pressure loss ΔP has elapsed. The atmospheric pressure in 12 can be accurately measured, and measurement takes time. This problem increases as the piping 30 becomes longer. In that respect, according to the example shown in FIG. 8, the atmospheric pressure in the air supply pipe 12 is constantly applied to the atmospheric pressure detection path 32, and the compressed air does not flow. Therefore, even if the atmospheric pressure detection path 32 is long, no pressure loss ΔP in the atmospheric pressure detection path 32 occurs, and when the supply mode is switched to the measurement mode, the pressure in the atmospheric pressure detection path 32 corresponds to the pressure loss ΔP. When there is no pulsating rise that switches to the air stop mode, that is, the “measurement mode”, the pressure in the air supply pipe 12 and the pressure in the atmospheric pressure detection path 32 are immediately stabilized.

  According to the bubble type liquid level gauge shown in FIG. 8, there is a problem that the number of pipes between the manifold 68 and the supply pipe 12 is increased by one, but immediately after switching from the “supply mode” to the “measurement mode”, the supply pipe 12. The internal pressure can be detected by the pressure sensor 54 and the level of the liquid can be displayed, so that a quick measurement is possible without waiting time. Further, since the pressure in the air supply pipe 12 is stabilized immediately after switching to the “measurement mode”, the liquid level can be measured with high accuracy.

  The examples shown in FIGS. 7 and 8 described above are novel bubble-type liquid level gauges which are the premise of the present invention. In the present invention, the bubble level gauge is further devised to eliminate construction problems. That is, in the example shown in FIG. 7, the outlet side port A1 of the first electromagnetic valve 65 and the inlet side port P2 of the second electromagnetic valve 66 are used. In the examples shown in FIGS. 7 and 8, the outlet side of the second electromagnetic valve 66 is used. The port A2 and the inlet side port P3 of the third electromagnetic valve 67 must be connected by pipes, and there is a problem in that the piping takes time.

  Therefore, the present inventor has come up with the idea of using a manifold 642 as shown in FIG. 4B and mounting a plurality of electromagnetic valves as shown in FIG. A manifold 642 shown in FIG. 4 is a manifold having a general configuration, and has an air inlet side port P, an air outlet side port R, and air passages respectively connected to these ports. The manifold 642 has a portion on which the first, second, and third electromagnetic valves 65, 66, and 67 are mounted. When these electromagnetic valves are mounted at predetermined positions, the inlet side ports P1, P2, and the like of the respective electromagnetic valves are provided. The p3 communicates with the inlet port P of the manifold 642, and the outlet ports A1, A2, A3 of each electromagnetic valve communicate with the outlet port R of the manifold 642. In other words, the manifold 642 connects a plurality of solenoid valves in parallel.

  Therefore, according to a general manifold as shown in FIG. 4, a plurality of electromagnetic valves are not connected in series, and an air passage connecting the electromagnetic valves is not branched. It was impossible to switch to “air supply mode”, “measurement mode”, and “measurement pressure atmospheric release” mode.

  The present invention has been made in view of the above points, and in a bubble-type liquid level gauge using a plurality of electromagnetic valves, a bubble-type liquid level gauge capable of using a manifold to reduce the installation man-hours. The purpose is to provide.

  The present invention includes an air supply pipe having at least a lower end portion immersed in a liquid in a tank, a compressed air supply source that supplies compressed air into the air supply pipe, a pressure sensor that measures the atmospheric pressure in the air supply pipe, and a pressure sensor A display unit that displays the liquid level in the tank based on the detection signal, a first electromagnetic valve that opens and closes a compressed air supply path from the compressed air supply source to the supply pipe, and an atmospheric pressure detection from the supply pipe to the pressure sensor A bubble type liquid level gauge having a second electromagnetic valve for opening and closing a path, and having a manifold on which the first electromagnetic valve and the second electromagnetic valve can be mounted. The manifold serves as a compressed air supply source. A main manifold having a connected air supply flow path and a sub manifold integrally coupled with the main manifold, and the air inlet side of the first electromagnetic valve is connected to the main manifold via the sub manifold. An air passage connecting the air inflow side and the air outlet side of a plurality of electromagnetic valves in series; an air passage communicating with the compressed air supply path; The most important feature is to have an air passage communicating with the atmospheric pressure detection path.

  By opening the first electromagnetic valve, compressed air is supplied from the compressed air supply source to the supply pipe, and the air pressure in the supply pipe rises. When the liquid level in the air supply pipe falls to the lower end of the air supply pipe, the compressed air in the intake pipe leaks into the liquid in a bubble shape, and the air pressure in the intake pipe becomes a pressure corresponding to the liquid level. By closing the first electromagnetic valve and opening the second electromagnetic valve, the air pressure in the air supply pipe is detected by the pressure sensor, and the liquid level in the tank is displayed on the display unit based on the detection signal. Even when a bubble level gauge is installed in each of a large number of tanks, piping from the compressed air supply source to individual bubble level gauges is not required, and the main manifold is used as a common manifold. Since it is sufficient to install a sub-manifold at the position and mount an electromagnetic valve on the sub-manifold to connect to the air supply pipe, the piping can be simplified. In addition, a main manifold having an air supply flow path connected to a compressed air supply source, and a sub manifold connected integrally with the main manifold, and a plurality of solenoid valves are mounted on the sub manifold. It is possible to switch to “mode” or the like.

  Hereinafter, embodiments of the bubble type liquid level gauge according to the present invention will be described with reference to the drawings. In addition, the same code | symbol was attached | subjected to the same component as the structure of the prior art example demonstrated so far and the structure of the prior invention example by this inventor.

  In FIG. 1, a liquid 14 such as oil or water is stored in a tank 10 of a ship. A pipe 30 is connected to the top surface of the tank 10 via a stand piece 16 and a flange 60. The pipe 30 is, for example, a pipe on a ship deck, and is connected to a manifold disposed in the control room 38. The pipe 30 functions as a compressed air supply pipe by opening / closing control of the first and second electromagnetic valves 65 and 66, and also functions as a pipe for taking out signal air. An air supply pipe 12 is attached to the stand piece 16 so as to hang down toward the bottom surface of the tank 10, and the air supply pipe 12 is immersed in the liquid 14 in the tank 10 from its lower end.

  The manifold includes a main manifold 63 and a sub-manifold 64, and an air passage for attaching a plurality of electromagnetic valves in advance and an air passage connected between the attached electromagnetic valves and to external piping are formed. The main manifold 63 and the sub manifold 64 are integrally coupled. The main manifold 63 is used as a common manifold, a sub manifold 64 is installed at an appropriate position of the main manifold 63, and a set of electromagnetic valves is mounted on the main manifold 63 up to the supply pipe 12, and an aeroelectric converter 52 described later. The pressure sensor 54 is piped. In other words, even when a bubble level gauge is installed for each of a plurality of tanks in a ship, the main manifold 63 is installed as a common one, and the sub manifold 64 is installed at an appropriate position of the main manifold 63. Install a set of solenoid valves on the pipes and make the necessary piping. By doing so, it is possible to simplify the conventional complicated piping of stretching the compressed air supply piping for each of the plurality of bubble-type liquid level gauges.

  In this embodiment, three electromagnetic valves 65, 66, 67 are attached to the sub manifold 64. The operation of each electromagnetic valve is controlled by a control board 56 that the aeroelectric converter 52 has. Each solenoid valve moves in one direction when the drive coil is excited to connect the air inflow side and the outlet side, and when the drive coil is not excited, it moves with an urging force to move the air inflow side and the outlet side. It is of a relatively simple construction configured to block the sides. The sub manifold 64 includes an air passage that connects the electromagnetic valves 65, 66, and 67 in series, an air passage that branches the air passage between the electromagnetic valves 65 and 66, and is connected to the pipe 30, and between the electromagnetic valves 66 and 67. The air passage is branched and connected to a pipe reaching the pressure sensor 54 in the aeroelectric converter 52. Further, the main manifold 63 has an air supply flow path 68 that has one end connected to the compressed air supply path from the air supply unit 40 and an air release flow path 69 that has one end opened to the atmosphere. The other ends of the air passages 68 and 69 are closed.

  When the first electromagnetic valve 65 is mounted on the sub manifold 64, the port P 1 on the air inflow side of the electromagnetic valve 65 is connected to the air supply flow path 68 of the main manifold 63 through the air passage of the sub manifold 64. The port A1 on the air outlet side is connected to the port P2 on the air inflow side of the second electromagnetic valve 66 through the air passage of the sub manifold 64. When the second electromagnetic valve 65 is mounted on the sub-manifold 64, the air outlet side port A2 is connected to the air inflow side port P3 of the third electromagnetic valve 67 through the air passage of the sub-manifold 64. Yes. When the third electromagnetic valve 67 is mounted on the sub-manifold 64, the air outlet side port A3 is configured to be connected to the air release channel 69 of the main manifold 63 via the air passage of the sub-manifold 64.

Similar to the above-described example, the compressor 34 serving as a compressed air supply source is provided, and an inboard regulator 36 and an air supply unit 40 are interposed between the compressor 34 and the manifold 64. The inboard regulator 36 adjusts the pressure of the compressed air sent out from the compressor 34 to, for example, about 7 kg / cm ² . The air supply unit 40 is disposed in the control room 38, and has a stop valve 42, a filter 44, a regulator 46, and a pressure gauge 48 in order from the compressor 34 side. An aeroelectric converter 52 and an indicator 58 are disposed in the control room 38. The aeroelectric converter 52 detects air pressure and converts it into an electrical signal, and includes a pressure sensor 54 and a control board 56 that controls the pressure indication value by the indicator 58 according to the output of the pressure sensor 54. . As described above, the air passage of the sub-manifold 64 interposed between the electromagnetic valves 66 and 67 branches and is connected to the pressure sensor 54 via the pipe 61. The control board 56 has a calculation function for calculating the detection output of the pressure sensor 54 and converting it to the liquid level in the tank 10 and displaying the liquid level on the indicator 58. The control board 56 is also installed with software for controlling the opening / closing operations of the electromagnetic valves 65, 66 and 67.

  Next, the operation of the first embodiment will be described. Depending on the opening / closing operation mode of the three electromagnetic valves 65, 66, 67, there are three operation modes, that is, an air supply mode, an air stop mode, and a measured pressure atmospheric discharge mode, as shown in FIG. The “air supply mode” is a mode in which compressed air is supplied from the compressed air supply source to the air supply pipe 12, that is, “air supply mode”. It is a mode for measuring, that is, a “measurement mode”. The “measured pressure atmospheric release mode” is an operation mode for performing zero point adjustment in which the compressed air applied to the pressure sensor is opened to the atmosphere to atmospheric pressure, and the indicated value of the indicator 58 at this time is zero. . In FIG. 3, SV1 indicates the first electromagnetic valve 65, SV2 indicates the second electromagnetic valve 66, and SV3 indicates the third electromagnetic valve 67.

  In the “air supply mode”, the first electromagnetic valve 65 opens the compressed air supply path, the second electromagnetic valve 66 closes the atmospheric pressure detection path connected to the pressure sensor 54, and the compressed air is supplied to the main manifold 63, the sub manifold 64, The air is supplied to the air supply pipe 12 through the pipe 30. In the “air stop mode”, the first electromagnetic valve 65 closes the compressed air supply path, only the second electromagnetic valve 66 opens to open the atmospheric pressure detection path, and the atmospheric pressure in the supply pipe 12 is changed to the sub manifold 64. The pressure sensor 54 of the aeroelectric converter 52 is applied via the pipe 61. In the “measured pressure atmospheric release mode”, only the third electromagnetic valve 67 opens, and the atmospheric pressure applied to the pressure sensor 54 is made the same as the atmospheric pressure via the sub manifold 64 and the main manifold 63.

  The “supply mode” in which only the first electromagnetic valve is opened and the “measurement mode” in which only the second electromagnetic valve is opened are controlled to be switched alternately and intermittently. Until the start of the air supply mode, the liquid level in the air supply pipe 12 is at the same level as the liquid level of the liquid 14 stored in the tank 10, and the air pressure in the air supply pipe 12 by executing the air supply mode. Rises and the level of the liquid level in the supply pipe 12 falls. Since the air supply mode and the measurement mode are executed alternately, the air pressure in the air supply pipe 12 rises stepwise at the beginning of the air supply. When the air pressure in the air supply pipe 12 rises and the liquid level in the air supply pipe 12 reaches the lower end of the air supply pipe 12, the compressed air leaks from the lower end of the air supply pipe 12 and bubbles in the liquid 14 in the tank 10. It rises and is released to the atmosphere. Accordingly, the air pressure in the air supply pipe 12 becomes an air pressure corresponding to the level (depth) of the liquid 14 in the tank 10, and the air pressure in the air supply pipe 12 does not change unless the level of the liquid 14 changes. Therefore, the level of the liquid level 14 at that time can be measured by reading the measured value when the measured value no longer fluctuates in the measurement mode. It should be noted that the intake air may be sucked into the air supply pipe 12 from the start of the air supply until the compressed air leaks from the lower end of the air supply pipe 12, and it is not always necessary to supply air in stages.

  In the “measured pressure atmospheric release mode” in which the first and second electromagnetic valves 65 and 66 are closed and the third electromagnetic valve 67 is opened, the atmospheric pressure applied to the pressure sensor 54 is the same as the atmospheric pressure. The indicated value of the indicator 58 is set to zero. That is, the measured pressure atmospheric release mode is a mode for zero point adjustment.

  The bubble type liquid level gauge according to the above embodiment is provided for each tank, and the air supply unit 40, manifold, static electricity converter 52, and indicator 58 of each liquid level gauge are put together in the control room 38. Centralized control and centralized monitoring. The automatic control program for each electromagnetic valve 65, 66, 67 is set in advance assuming a tank load pattern or a lift pattern, and the execution of the automatic control program allows switching of the detection process and adjustment of the supply amount of compressed air. Done.

  According to the first embodiment described above, even when a bubble type liquid level gauge is installed for each of a large number of tanks, there is no need to pipe from the compressor 34, which is a compressed air supply source, to individual bubble type liquid level gauges. It is sufficient to use the manifold 63 as a common manifold, install a sub-manifold 64 at a position adjacent to the main manifold 63, and mount a set of electromagnetic valves on the manifold to connect to the supply pipe 12 and the pressure sensor 54. Piping can be simplified. In addition, a main manifold 63 having an air supply flow path 68 connected to a compressed air supply source, a sub manifold 64 coupled to the main manifold 63, and a plurality of electromagnetic valves are mounted on the sub manifold 64 are used. Nevertheless, it is possible to switch to “air supply mode”, “measurement mode” and the like. The main manifold 63 is fixed as a simple shape having an air supply flow path 68, and the sub manifold 64 is redesigned so as to have a configuration adapted to a combination of a set of electromagnetic valves and piping to the outside. It is possible to flexibly cope with the configuration corresponding to the configuration of the liquid level gauge.

  Next, Example 2 shown in FIG. 2 will be described. The second embodiment has a configuration in which piping is added to the first embodiment. That is, the compressed air outlet side port A1 of the first electromagnetic valve 65 is connected to the air supply pipe 12 via the air passage of the sub manifold 641 and the compressed air supply path 30, and the air inflow side port P2 of the second electromagnetic valve 66 is The sub-manifold 641 is connected to the air supply pipe 12 through the air passage and the atmospheric pressure detection path 32. In the first embodiment, the first and second electromagnetic valves 65 and 66 are connected via the air passage of the sub-manifold 64, and the middle of the branch is branched and connected to the supply pipe 12 by one pipe 30. In Example 2, as described above, the first and second electromagnetic valves 65 and 66 are separated from each other, and are connected to the supply pipe 12 via the compressed air supply path 30 and the atmospheric pressure detection path 32, respectively. Yes. In order to realize such a configuration, the sub-manifold 641 includes an air passage leading to the pipe 30 for connecting the air outlet side port A1 of the first electromagnetic valve 65 to the air supply pipe 12, and an air inflow of the second electromagnetic valve 66. It has an air passage leading to a pipe 32 for connecting the side port P2 to the air supply pipe 12. The sub manifold 641 does not have an air passage that directly connects the air outlet side port A1 of the first electromagnetic valve 65 and the air inflow side port P2 of the second electromagnetic valve 66. Other than that, the configuration is the same as that of the first embodiment.

  According to the second embodiment, the atmospheric pressure in the air supply pipe 12 is constantly applied to the atmospheric pressure detection path 32, and the compressed air does not flow. Therefore, even if the atmospheric pressure detection path 32 is long, the pressure loss ΔP in the atmospheric pressure detection path 32 does not occur. When the supply mode is switched to the measurement mode, the pressure in the atmospheric pressure detection path 32 is reduced to the pressure loss ΔP. There is no corresponding pulsating rise. Accordingly, there is a problem that the number of pipes between the sub manifold 641 and the supply pipe 12 is increased by one. However, as soon as the “supply mode” is switched to the “measurement mode”, the pressure in the supply pipe 12 is detected by the pressure sensor 54. In addition, since the liquid level can be displayed on the display meter 58, quick measurement can be performed without waiting time. Further, since the pressure in the air supply pipe 12 is stabilized immediately after switching to the “measurement mode”, the liquid level can be measured with high accuracy. In the case of the second embodiment, the same effect as that of the first embodiment can be obtained by including the main manifold 63 and the sub manifold 641.

The bubble type liquid level gauge according to the present invention can be applied to a cargo storage tank, a ballast tank, etc. in a ship such as a tanker, an LNG ship, a cargo ship, etc. It can be applied to tanks for various purposes.
In addition, although the gas supplied to an air supply pipe | tube was demonstrated as air in each Example, depending on the kind of cargo, it may be gases other than air.
The number of electromagnetic valves used in one bubble type liquid level gauge is not limited to three as in the embodiment shown in the figure, and may be used more than that. For example, another electromagnetic valve is provided in parallel with the first electromagnetic valve, and this separate electromagnetic valve is operated at the same time as the first electromagnetic valve as necessary. Only the first electromagnetic valve may be operated.

It is a systematic diagram which shows Example 1 of the bubble-type liquid level gauge concerning this invention. It is a systematic diagram which shows Example 2 of the bubble-type liquid level meter concerning this invention. It is a figure which shows the opening / closing operation | movement in each operation mode of each electromagnetic valve of Example 1. FIG. The principal part of the bubble-type liquid level gauge concerning the prior art by this inventor is shown, (a) is a conceptual diagram of an electromagnetic valve, (b) is a conceptual diagram of a manifold. It is a systematic diagram which shows the example of the conventional bubble type liquid level gauge. It is a longitudinal cross-sectional view which shows the internal structure of the air purge head in the said conventional bubble type liquid level gauge. It is a systematic diagram which shows an example of the bubble type liquid level gauge concerning the prior art by this inventor. It is a systematic diagram which shows another example of the bubble-type liquid level meter concerning the prior art by this inventor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tank 12 Supply pipe 14 Liquid 30 Piping 32 Piping 34 Compressor as compressed air supply source 54 Pressure sensor 63 Main manifold 64 Sub manifold 641 Sub manifold 65 First electromagnetic valve 66 Second electromagnetic valve 67 Third electromagnetic valve

Claims (7)

Based on an air supply pipe having at least a lower end immersed in the liquid in the tank, a compressed air supply source for supplying compressed air into the air supply pipe, a pressure sensor for measuring the atmospheric pressure in the air supply pipe, and a detection signal of the pressure sensor A display for displaying the liquid level in the tank, a first electromagnetic valve for opening and closing a compressed air supply path from the compressed air supply source to the supply pipe, and an atmospheric pressure detection path from the supply pipe to the pressure sensor. A bubble level gauge having a second electromagnetic valve,
A manifold capable of mounting the first electromagnetic valve and the second electromagnetic valve;
The manifold includes a main manifold having an air supply channel connected to a compressed air supply source, and a sub manifold integrally coupled to the main manifold.
The air inlet side of the first solenoid valve is connected to the air supply flow path of the main manifold via the sub manifold.
The sub manifold includes an air passage that serially connects an air inflow side and an air outlet side of a plurality of mounted electromagnetic valves, an air passage that communicates with the compressed air supply path, and an air passage that communicates with the pressure detection path A bubble type liquid level gauge characterized by comprising:   The sub manifold can be equipped with a third electromagnetic valve that can open a pressure detection path from the supply pipe to the pressure sensor, and the main manifold communicates with the air outlet side of the third electromagnetic valve through the sub manifold. The bubble type liquid level gauge according to claim 1, which has an open channel.   The bubble type liquid level gauge according to claim 1 or 2, wherein the opening / closing operation of each electromagnetic valve is controlled by software.   In the air supply mode in which the first electromagnetic valve opens the compressed air supply path, the second electromagnetic valve closes the atmospheric pressure detection path, and in the measurement mode in which the second electromagnetic valve opens the atmospheric pressure detection path, the first electromagnetic valve is compressed air. The bubble type liquid level gauge according to claim 1, wherein the supply path is closed.   The bubble type liquid level gauge according to claim 1, wherein the first electromagnetic valve and the second electromagnetic valve are controlled so that an air supply mode and a measurement mode are alternately performed.   The first electromagnetic valve and the second electromagnetic valve are connected in series through a sub-manifold, and the sub-manifold is connected to a supply pipe by branching between the first electromagnetic valve and the second electromagnetic valve. The bubble type liquid level gauge as described. Based on an air supply pipe having at least a lower end immersed in the liquid in the tank, a compressed air supply source for supplying compressed air into the air supply pipe, a pressure sensor for measuring the atmospheric pressure in the air supply pipe, and a detection signal of the pressure sensor A display for displaying the liquid level in the tank, a first electromagnetic valve for opening and closing a compressed air supply path from the compressed air supply source to the supply pipe, and an atmospheric pressure detection path from the supply pipe to the pressure sensor. A bubble level gauge having a second electromagnetic valve,
A manifold capable of mounting the first electromagnetic valve and the second electromagnetic valve;
The manifold includes a main manifold having an air supply channel connected to a compressed air supply source, and a sub manifold integrally coupled to the main manifold.
The air inlet side of the first solenoid valve is connected to the air supply flow path of the main manifold via the sub manifold.
The air outlet side of the first solenoid valve is connected to the air supply pipe via the sub manifold and the compressed air supply path,
A bubble type liquid level gauge in which the air inflow side of the second electromagnetic valve is connected to an air supply pipe through a sub manifold and an air pressure detection path.

Images