JP2012068195A - Liquid level measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level measuring apparatus which can be attached/detached to/from a tank according to necessity and can be mounted to the tank under operation for loading.SOLUTION: The apparatus includes a sensor 1 for detecting a liquid level without touching the liquid, a radio transmitter/receiver 3 for transmitting a liquid level signal detected, a built-in power supply 5 for supplying power to drive the sensor 1 and the radio transmitter/receiver 3, and a housing 10 for housing the sensor 1, the radio transmitter/receiver 3 and the built-in power supply 5 inside of a shield space. The housing 10 is detachably attached on the upper part of one of multiple tanks provided. Each of the tanks has a tank information input part for inputting an identification signal of each tank to the radio transmitter/receiver 3 through attachment of the housing 10. The radio transmitter/receiver 3 transmits the liquid level signal with the tank identification signal.

Description

  The present invention mainly relates to a liquid level measuring device for measuring a level surface of a liquid stored in a tank of a ship, and even if a ship having a large number of tanks has a small number of measuring apparatuses, it is useful. It is devised so that it can be fulfilled.

  Ships such as tankers are equipped with various tanks, such as ballast tanks for adjusting the balance of the hull and fuel tanks for storing engine fuel, in addition to tanks for storing oil such as crude oil. Has about 30 tanks. Since it is necessary to keep track of the amount of liquid stored in each tank whenever necessary, a liquid level measuring device (also called “liquid level gauge”) is installed in each tank. Yes.

  The liquid level measuring device is useful in a ship when loading / unloading work at a port, in order to load / unload a predetermined amount of liquid in each tank, or to measure the amount of stored liquid in real time. In order to do so, a liquid level measuring device is used. Therefore, conventionally, a liquid level measuring device has been installed in all the tanks included in the ship as a dedicated tank facility.

  There are various measuring methods of the liquid level measuring device installed in the tank of the ship. A float type that has a float that rises and falls according to the liquid level along a vertically installed guide, detects the position of this float, at the bottom of the tank Pressure-receiving type that determines the liquid level from the detection signal of the installed pressure sensor. Open the tip of the air supply pipe at the bottom of the tank, send compressed air into this air supply pipe to leak air from the tip, and supply air at that time Bubble type that determines the liquid level from the air pressure in the pipe, radio wave type that transmits radio waves toward the liquid level, receives radio waves that are reflected back from the liquid level, and calculates the liquid level based on the time difference or frequency difference from the transmitted radio wave Etc. are known.

  Regardless of the liquid level measuring device of any measurement method, conventionally, the liquid level measuring device is installed in all the tanks provided in the ship as described above. However, a liquid level measuring device is required in a ship when cargo handling work is performed at a port of call. Moreover, not all of the tanks in a ship are handled at the same time, and there are three or four tanks that will be handled at the same time. Yes. Therefore, the liquid level measuring device is installed in the tank for use when carrying out cargo handling, and is in an unused state for most of the time including during other voyages. In addition, the liquid level measuring device requires power supply and transmission of measurement data, and the cables for that purpose are routed on the deck of the ship. Stored in a pipe. However, the cost of laying such a cable on the deck of a large area ship exceeds the cost of the liquid level measuring device itself. In addition, it is no exaggeration to say that the environmental conditions of the tank of the ship where the liquid level measuring device is installed are poor, and the liquid level measuring device installed under such conditions has a short life and guarantees normal operation. Therefore, it is necessary to perform periodic inspections at a relatively short cycle at all times.

  Now, if there is a liquid level measuring device that is relatively light and easy to carry, and can be attached to and detached from the tank as needed, the liquid level measuring device should be attached only to the tank during cargo handling operations. Cargo handling can be done by When the cargo handling of the tank is completed, the liquid level measuring device may be removed from the tank, and the liquid level measuring device may be attached to the tank that will perform the next cargo handling and the cargo handling may be performed while measuring the liquid level of the tank. Therefore, cargo handling can be performed while using, for example, 3 to 4 liquid level measuring devices. Moreover, it is not necessary to install a liquid level measuring device in every tank, and it is not necessary to lay cables for power lines and signal lines at high cost, and piping work for that is not necessary. As a result, the cost of the liquid level measuring device can be greatly reduced, and when not in use, the life of the liquid level measuring device can be extended by storing it in a good environment. it can. Furthermore, even if maintenance personnel do not go to the ship, many effects can be expected, such as being able to perform maintenance by sending the liquid level measuring device to the factory.

  Accordingly, the present inventor has started the development of a liquid level measuring device that is relatively light and can be easily carried and can be attached to and detached from the tank as needed. In order to realize such a liquid level measuring device, it is assumed that a tank storing volatile liquid is provided, an explosion-proof function is provided, measurement data relating to each tank can be identified, It is necessary to solve technical problems such as being able to easily transmit measurement data to a control room.

The following documents describe technical elements that can possibly solve the technical problems described above.
In Patent Document 1, a liquid level meter having a wireless transmission unit is provided in each tank, and a plurality of transmission signals including a self-identification code and a liquid level signal are generated at timings generated by random number generation means having different random number sequences. Provide a transmitter to transmit, make the carrier wave frequency of the transmission radio waves from the transmitters of the level gauges of all tanks the same, and check whether the received signal is the correct signal to one receiver provided at the monitoring station There is described a wireless level gauge signal transmission apparatus provided with means for checking and means for recognizing a tank and a liquid level signal from the signal if the signal is correct.

  In Patent Document 2, an optical fiber cable for supplying light energy from the outside into a pipe, a solar cell for converting light energy into electric energy and supplying power, and power supplied from the solar cell operate. A power supply device is described that includes an electronic device, a gas flow path formed in the piping, the electronic device isolated from the gas flow channel, and a room for accommodating a solar cell.

  Patent Document 3 discloses a related equipment storage box for single unloading that contains equipment (for example, a liquid amount indicator) necessary for single unloading to a liquid storage tank, and the power source of the equipment is connected to the box main body or A solar cell installed in the vicinity or a wind power generator installed in the vicinity is described. And the liquid quantity indicator which receives the signal from a liquid level meter by radio | wireless can be incorporated in a box now.

JP-A-6-43000 JP-A-9-107643 JP 2001-206500 A

  In Patent Documents 1 to 3, as described above, a technique for wirelessly transmitting measurement data obtained by a liquid level gauge to, for example, a control room, optical energy is transmitted for explosion prevention, and this is converted into electrical energy to be used as a power source. And a technique for collectively monitoring the liquid level of a plurality of tanks by receiving a liquid level signal transmitted from a plurality of liquid level gauges with a single receiver.

  However, even if a solar cell is used to convert light energy into electric power or power is obtained by a wind power generator, according to the conventional technical idea, it is necessary to connect the liquid level measuring device main body and the power source with a cable. is there. Accordingly, as the present invention aims, even if several liquid level measuring devices are moved and the liquid level of all the tanks is measured, the power cable and the signal cable cannot be eliminated. In addition, Patent Documents 1 to 3 do not describe any liquid level measuring device that can be attached to and detached from the tank as necessary, and any of the inventions described in Patent Documents has a measuring device or sensor built in a tank or the like. It has been. Therefore, according to the technical ideas described in Patent Documents 1 to 3, it is necessary to install a liquid level measuring device in each tank as is conventionally done, and the liquid level measuring device itself. There are problems such as an increase in installation costs, an increase in costs such as cable wiring and piping, an increase in maintenance costs, and the like.

  The present invention eliminates such conventional problems, i.e., does not require piping work, can be carried relatively easily with a relatively light weight, and can be attached to and detached from a tank as needed. , Load the liquid level measuring device only to the tank that performs the cargo handling work, and when the cargo handling of the tank is finished, remove the liquid level measuring device from the tank, and then perform the cargo handling of this liquid level measuring device Provides a liquid level measuring device that can be mounted on a tank to perform cargo handling while measuring the liquid level of this tank, and that enables liquid level measurement information for each tank to be aggregated in a batch. The purpose is to do.

  The present invention is a liquid level measuring device for measuring a liquid level of a liquid stored in a tank for storing a liquid, the sensor detecting the liquid level without contacting the liquid, A wireless transmitter / receiver that transmits a liquid level signal detected by the sensor to the outside, a built-in power supply that supplies power to drive the sensor and the wireless transmitter / receiver, and the sensor in a sealed internal space, A housing that houses a wireless transceiver and a built-in power source, and the housing is detachably provided on an upper part of the plurality of tanks, and each of the tanks is individually mounted by mounting the housing. A tank information input unit configured to input a tank identification signal to the wireless transceiver, the wireless transceiver including the tank identification signal and the liquid level; The most important feature to send a signal.

The built-in power source may be a secondary battery, and may be charged from an external power source through the power relay unit.
The power relay unit is composed of a transformer, and is configured such that power is relayed from the AC external power source into the housing by magnetic coupling by the transformer core. In the housing, the relay AC power source is converted to DC. A charging circuit for charging the secondary battery may be provided.
A part of the core of the transformer is provided on the housing side, the other part of the core of the transformer is provided on the charging device side, and the housing removed from the tank is attached to the charging device, whereby a part of the core of the transformer is provided. The other part of the transformer core may be magnetically coupled.
A barrier circuit that suppresses excessive voltage and current may be provided in a power supply circuit from the built-in power supply to the sensor and the wireless transceiver.

The housing mounting part to the tank and the receiving part of the tank to which the mounting part is mounted are provided with flanges, and a flange ("taga") is provided to tighten both flanges and bring the two flanges into close contact with each other. Good.
A protective plate for sealing the internal space of the tank may be fixed to the receiving portion of the tank to which the housing is attached.
The protective plate may be made of a material that transmits radio waves, and the sensor may be a radio wave level gauge.

  According to the present invention, it is not necessary to install liquid level measuring devices in all the tanks, and cargo handling can be performed while using, for example, 3 to 4 liquid level measuring devices. As a result, the cost applied to the liquid level measuring device can be greatly reduced, and the life of the liquid level measuring device can be extended by storing the liquid level measuring device in a good environment when not in use. Even if maintenance personnel do not go to the ship, the liquid level measuring device can be sent to the factory for maintenance, and the calibration accuracy during maintenance can be improved.

It is a longitudinal cross-sectional view which shows one Example of the liquid level measuring apparatus which concerns on this invention. It is a circuit diagram which shows the example of the electric circuit integrated in the said Example. It is a longitudinal cross-sectional view which shows another Example of the liquid level measuring apparatus which concerns on this invention. It is a top view which shows the bag in the said Example. It is a longitudinal cross-sectional view which shows another Example of the liquid level measuring apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows another Example of the liquid level measuring apparatus which concerns on this invention. It is a circuit diagram which shows the example of the charging device applicable to this invention.

  Embodiments of the liquid level measuring device according to the present invention will be described below with reference to the drawings.

  In FIG. 1, the code | symbol 11 has shown the sensor mounting base provided in the upper part of the tank. The sensor mounting base 11 has a cylindrical shape, and a first flange 12 is provided integrally with the sensor mounting base 11 at an upper end of the sensor mounting base 11 by an appropriate fixing means, and a second flange 13 is provided on the first flange 12. They are stacked and integrated. A central hole is provided in the first flange 12 and the second flange 13, but the central hole is blocked by a protective plate 14 that is sandwiched and fixed between the first flange 12 and the second flange 13. The internal space of the tank is sealed.

  The protective plate 14 is made of a material that can transmit radio waves, for example, a dielectric such as fluororesin. Further, the protection plate 14 is formed in a conical shape with a gentle inclination, and is fixed with the top of the conical shape facing the lower surface of the planar antenna 15 of the liquid level measuring device described in detail later. The protection plate 14 and the planar antenna 15 are attached so that the mutual distance is as short as possible so that the protection plate 14 does not adversely affect the electromagnetic field of the planar antenna 15. The second flange 13 is a receiving portion on the tank side that can receive and mount the housing 10 of the liquid level measuring device.

  In FIG. 1, the code | symbol 20 has shown the liquid level measuring apparatus which can be attached or detached to the receiving part of the said tank. The liquid level measuring device 20 has a housing 10 whose bottom surface is open. A planar antenna 15 is attached to the lower part of the housing 10, and the release surface of the housing 10 is closed with the planar antenna 15. A sealed space 16 is formed by being surrounded by the housing 10 and the planar antenna 15, and the sensor 1, the built-in battery 5, the charging circuit 6, and the wireless transceiver 3 are arranged in the sealed space 16. The sensor 1 is a sensor that detects the liquid level of the liquid stored in the tank without contacting the liquid. In this embodiment, the sensor 1 radiates radio waves toward the liquid surface and is reflected by the liquid surface. It consists of a radio wave level gauge that calculates the liquid level according to the phase shift of the returned radio wave. The planar antenna 15 radiates the radio wave generated by the sensor 1 toward the liquid level, receives the radio wave reflected and returned from the liquid level, and inputs the received signal to the sensor 1. The sensor 1 and the planar antenna 15 are connected by a transmission path 17 for these signals.

  There are various types of liquid stored in the tank. For example, when petroleum is stored, the petroleum may evaporate and paraffin is condensed on the protective plate 14. Since the flat antenna 15 has the strongest electric field strength at the center of the flat antenna 15, if paraffin is condensed near the center of the protective plate 14 facing the central portion of the flat antenna 15, the electric field strength of the flat antenna 15 becomes weak, and the measurement accuracy Decreases. Therefore, the protection plate 14 has a conical shape with its top facing upward, and paraffin condensed on the protection plate 14 flows down toward the peripheral portion along the conical surface, and is devised to suppress radio wave transmission disturbance due to paraffin. .

  The built-in battery 5 is a power source for supplying power for driving the sensor 1 and the wireless transceiver 3 to drive them. The built-in battery in this embodiment is composed of a rechargeable secondary battery and can be charged by the charging circuit 6.

  The wireless transmitter / receiver 3 transmits a liquid level signal detected by the sensor 1 to the outside. An antenna 31 is pulled out from the wireless transmitter / receiver 3, and the antenna 31 is further pulled out of the housing 10. A radio wave modulated by the liquid level signal is emitted from 31. This radio wave is received by a receiver (not shown), the liquid level signal is demodulated and input to a centralized control panel called a cargo handling console (not shown), and the liquid of each tank measured by the liquid level measuring device is displayed on the console display. The surface level is displayed.

  In addition to the above-mentioned petroleum, the liquid stored in the tank includes various liquids such as highly volatile liquids and highly ignitable liquids. Even if it occurs, it is necessary to have an explosion-proof structure so that sparks and heat do not leak. Therefore, in the illustrated embodiment, the internal space of the housing 10 is hermetically sealed, and a valve 18 for injecting an inert gas from the outside into the internal space of the housing 10 is provided.

  The embodiment of the liquid level measuring device shown in FIG. 1 is compactly packed so that it can be arbitrarily attached only to a tank that performs a cargo handling operation, and the liquid level is measured without contacting the liquid stored in the tank. It is a radio wave type liquid level measuring device. That is, one liquid level measuring device is attached to an unspecified tank. Therefore, unlike a conventional liquid level measuring device, a specific liquid level measuring device is not installed in a specific tank, so when transmitting information on the liquid level from the liquid level measuring device, It is also necessary to transmit an identification signal that identifies in which tank the information is information. Therefore, in the illustrated embodiment, a code setting switch 2 as a tank information input unit is attached to transmit a signal for identifying a tank in which the liquid level measuring device is mounted, for example, an ID code signal. The code setting switch 2 can use, for example, a type of switch called a digital switch that can manually set a code having an appropriate number of bits, and sets an identification code set for each tank. It is supposed to be.

  However, manual code setting is likely to cause incorrect settings, so if a liquid level measuring device is installed in each tank, for example, the unevenness set in each tank will enter tank information on the liquid level measuring device side. An identification code may be automatically set by turning on and off each digit of a code setting switch as a unit. Alternatively, any setting means may be employed, such as identifying the tank by reading a magnetically or optically set code on the tank side with a magnetic or optical reader on the liquid level measuring device side. That's fine.

  An object of the liquid level measuring apparatus according to the present invention is to enable easy attachment to and detachment from an unspecified tank. Therefore, in the embodiment shown in FIG. 1, a flange 101 is provided on the outer periphery of the bottom of the housing 10 of the liquid level measuring device 20, and this flange 101 is placed on the second flange 13 on the tank side. Is configured to be fastened with a bolt 19. When the handling of one tank is completed, the liquid level measuring device 20 attached to the tank can be removed by loosening the bolt 19 and then attached to the tank that performs the handling. Since the liquid level measuring device 20 is of a radio wave type, there is no member that is not in contact with the liquid in the tank and extends toward the tank. In addition to this, the liquid level measurement data in the tank and the identification signal of each tank are transmitted wirelessly and are driven by a built-in battery. It is possible to attach and detach easily.

  FIG. 2 shows an example of an electric circuit applied to the above embodiment. This electric circuit is characterized by the charging circuit of the built-in power supply 5. In FIG. 2, reference numeral 1 denotes a sensor, 2 denotes a tank information input unit, 3 denotes a wireless transceiver, 5 denotes a built-in power supply, and 6 denotes a charging circuit. It corresponds to a member or circuit.

  In FIG. 2, the code | symbol 7 has shown the electric power relay part. The power relay unit 7 is provided to charge the built-in power source 5 of the liquid level measuring device with an external power source, and is constituted by a transformer in the example shown in FIG. For example, a commercial AC power supply is connected to the primary winding 71 of the transformer. The charging circuit 6 is connected to the secondary winding 72 of the transformer. The primary winding 71 and the secondary winding 72 of the transformer are magnetically coupled by a core, but the core around which the primary winding 71 is wound and the core around which the secondary winding 72 is wound are separated. For example, by attaching the liquid level measuring device removed from the tank to the charging device, the core on the charging device side around which the primary winding 71 is wound and the core on the liquid level measuring device side around which the secondary winding 72 is wound. The AC windings are configured to be coupled to each other so as to be magnetically coupled, and an AC voltage corresponding to the turn ratio of the primary winding 71 and the secondary winding 72 is generated in the secondary winding 72.

  The AC voltage generated in the secondary winding 72 is converted into a DC voltage by a charging circuit 6 having a rectifying diode D1, a smoothing capacitor C1, and a resistor R1, and is input to the built-in power supply 5. It has become. The built-in power supply 5 has a rechargeable secondary battery 51, and the secondary battery 51 is charged by a DC voltage supplied from the charging circuit 6. The diode D2 is for preventing a backflow to the secondary battery 51.

  The built-in power supply 5 supplies power to the sensor 1 and the wireless transceiver 3 via the barrier circuit 4, and the sensor 1 and wireless transceiver 3 are driven by the DC power supplied from the built-in power supply 5. ing. The barrier circuit 4 includes a fuse 41 that interrupts an overcurrent when it flows, a constant voltage diode 42 that applies only a constant voltage to the sensor 1 and the wireless transceiver 3 even when an overvoltage is applied, It has a protective resistance R2.

  According to the first embodiment described above, one liquid level measuring device can be used while being attached to and detached from a plurality of tanks. Therefore, for example, even if a tanker has about 30 tanks, there are 3 to 4 tanks that carry out cargo handling at the same time, so prepare 4 to 5 liquid level measuring devices including spare liquid level measuring devices. It is sufficient that the liquid level measuring device is not installed in all the tanks, so that the cost for the liquid level measuring device can be greatly reduced. The spare liquid level measuring device is sent to the factory for maintenance, and when the maintenance is completed, it is taken to the site of cargo handling and used, and an alternative liquid level measuring device is sent to the factory for maintenance. Rotation is also possible. In addition, the liquid level measuring device can be stored in a good environment except when it is used for cargo handling, etc., so that the life of the liquid level measuring device can be extended in combination with the periodic rotation. There are also advantages.

  3 and 4 show a second embodiment. Constituent parts or constituent members substantially the same as the constituent parts or constituent members of the first embodiment are denoted by the same reference numerals. 3 and 4, a protective plate 14 is placed on the first flange 12 fixed to the upper end of the sensor mounting base 11 of the tank, and a cylindrical interposed member 131 is placed on the peripheral edge of the protective plate 14. An inward flange 132 formed at the lower end is placed. The inward flange 132 and the first flange 12 are fastened with bolts, and the first flange 12, the protection plate 12, and the interposition member 131 are integrally coupled.

  An outward flange 133 is formed on the upper end portion of the interposition member 131, and the liquid level measuring device 30 is detachably mounted on the flange 133. The liquid level measuring device 30 includes a housing 10 in which a bottomed cylindrical member is turned down, and a support plate 111 fixed to a lower surface of a flange 102 formed at an open lower end edge of the housing 10. Yes. A housing of the liquid level measuring device 30 is configured by the integrated support plate 111 and the housing 10, and the inner housing 110 is fixed to the upper surface of the support plate 111 in the housing, and the sensor 1, wireless communication is performed by the inner housing 110. The transceiver 3 is surrounded. In the inner housing 110, as in the first embodiment, a built-in power source, a tank information input unit, and the like are arranged. A planar antenna 15 is fixed to the lower surface of the support plate 11. The measuring method of the liquid level measuring device 30 is the same radio wave type as in the first embodiment.

  The second embodiment is different from the first embodiment in the mounting structure of the liquid level measuring device 30 as described below. The flange 102 of the housing 10 is placed on the flange 133 of the interposed member 131 together with the support plate 111, and the flange 102 and the flange 133 are brought into close contact with each other by a flange 25. FIG. 4 shows the collar 25. The flange 25 has a semicircular main body portion, and both end portions of the main body portion are bent portions 27 directed outward. The main body portion of the flange 25 has a semicircular cross-sectional shape, and the dimension is set so that the total thickness of the flange 133, the support plate 111, and the flange 102 is included in the semicircle. Yes.

  The two flanges 25 are used as a pair, and are formed in a circular shape by making both bent portions 27 face each other, and the flange 133 and the flange 102 are surrounded by a pair of circular flanges 25 forming the circular shape. Then, bolts 28 are inserted into the bent portions 27 of the set of flanges 25 facing each other, and nuts are screwed into the bolts 28 to tighten the set of flanges 25 together. The set of flanges 25 tightens the periphery of the flange 133 and the flange 102 from the radially outer side toward the inner side. Since the cross-section of the main body portion of the flange 25 is semicircular as described above, the flange 133 faces upward in FIG. 3 on the inner circumferential surface of the flange 25 by the tightening force of the flange 25. Receives a downward force, and both the flange 133 and the flange 102 are brought into close contact with each other in a manner in which the support plate 111 is interposed. In order to remove the liquid level measuring device 30 attached to the tank, the pair of fastened scissors 25 may be loosened.

  As described above, according to the second embodiment, the liquid level measuring device 30 can be easily attached to and detached from the tanks by fastening and loosening the pair of flanges 25, and a small number of liquids can be added to a large number of tanks. An attachment / detachment structure suitable for the liquid level measuring device according to the present invention in which the surface measuring device is used repeatedly can be obtained. In addition, the same effect as described in the first embodiment can be obtained.

  The measuring method of the liquid level measuring device according to the present invention is arbitrary as long as the liquid level can be detected without contacting the liquid. For example, it may be a radio wave type liquid level measuring device provided with a horn antenna 36 as in the embodiment shown in FIG. In this embodiment, an antenna mounting plate 112 is fixed to the upper end of the sensor mounting base 11 provided at the upper part of the tank, and a horn antenna 36 extending downward from a repeater 34 attached to the mounting plate 112 is mounted on the mounting base. It penetrates 112 and faces the liquid surface. The tank is sealed by a mounting plate 112 and a repeater 34. A cylindrical second sensor mounting base 114 is fixed to the upper surface of the mounting plate 112 so as to surround the repeater 34, and a flange formed on the upper end portion of the second sensor mounting base 114 and a housing of the liquid level measuring device. The flange formed in 10 is overlapped. By tightening both flanges with the flange 25 and loosening the tightening, the liquid level measuring device can be attached to and detached from the sensor mounting base 11 as in the second embodiment.

  In the housing 10, there are arranged a sensor 1 for detecting the liquid level of the liquid in the tank without contacting the liquid, and a radio transceiver 3 for transmitting a liquid level signal detected by the sensor 1 to the outside. Yes. The housing 10 is provided with a built-in power source that supplies power for driving the sensor 1 and the wireless transceiver 3 to the sensor 1 although not shown. The sensor mounting base 114 of each tank has a tank information input unit for inputting an identification signal of each tank to the wireless transceiver 3 by mounting the housing 10, and the wireless transceiver 3 A liquid level signal detected by the sensor 1 is transmitted together with the identification signal.

In this third embodiment, a repeater 34 and a horn antenna 36 are installed in each tank, and a housing 10 and a liquid level measuring device incorporated in the housing 10 are detachable from each tank. . When the liquid level measuring device is mounted on the tank, the sensor 32 on the liquid level measuring device side and the relay 34 on the tank side are connected by connecting the cable 32 to an appropriate connector provided on the sensor mounting base 114 and the housing 10. Are to be connected.
This third embodiment also has the same effect as the previous embodiment.

  FIG. 6 shows a fourth embodiment. This embodiment also shows a liquid level measuring device called a radio wave type, and uses a parabolic antenna 40 instead of the planar antenna in the first and second embodiments. The parabolic antenna 40 is installed in the sensor mounting base 11 of each tank. An antenna support plate 116 is fixed to the upper end of the sensor mounting base 11. The tank 44 is kept airtight because the shaft 44 of the parabolic antenna 40 penetrates through the support plate 116 and the support plate 116 and the shaft 44 are fixed in an airtight manner. A sub-reflecting mirror 42 is integrally attached to the tip of the shaft 44 on the tank side. The upper portion of the shaft 44 protrudes to the upper surface side of the support plate 116, and a cylindrical second sensor mounting base 118 is fixed on the support plate 116 so as to surround the upper portion of the shaft 44.

  The liquid level measuring device has a housing 10 in which a sensor 1, a wireless transceiver 3, a built-in power source (not shown), and other components are incorporated. The flange provided at the lower end portion of the housing 10 and the flange provided at the upper end portion of the second sensor mounting base 118 are overlapped, and these flanges can be fastened by the flange 25. As described above, the heel 25 can be attached to and detached from the tank by tightening or relaxing the heel 25. The transducer 38 extends downward through the support plate 111 fixed to the lower end of the housing 10, and the shaft 44 of the parabolic antenna 40 is fitted to the transducer 38 with the liquid level measuring device attached to the tank. It is supposed to let you.

  In the fourth embodiment, the parabolic antenna 40 is installed in each tank, and the housing 10 and the liquid level measuring device incorporated in the housing 10 are detachable from each tank. The fourth embodiment also has the same effect as the above-described embodiment.

  FIG. 7 shows an example of a charging device applicable to the present invention. The liquid level measuring device according to the present invention is characterized in that it is configured to be detachable from an arbitrary tank, and it is desirable that the built-in power source be as simple as possible. Therefore, the built-in power source is a rechargeable secondary battery, and when the liquid level measuring device is not operated, the built-in power source may be charged by mounting the liquid level measuring device together with the charging device. In addition, it is desirable that the main power source of the charging device uses energy existing in the natural world such as sunlight, wind force, temperature difference, and vibration.

  A DC (direct current) power supply 50 shown in FIG. 7 is a power supply that generates electric power using the energy existing in the natural world as described above. In ships such as tankers, explosion-proof measures are strictly required, so the built-in power supply of the charging device and the liquid level measuring device can relay power without contact so that no sparks are generated when electrical connection or disconnection occurs. It is desirable to make it. Therefore, in the example shown in FIG. 7, the DC power generated as described above is interrupted by the oscillation circuit 52, and this intermittent power is supplied to the built-in power of the liquid level measuring device via the transformer 7 as a power relay unit. To communicate.

  The transformer 7 has a first core 73 around which a primary winding 71 is wound and a second core 74 around which a secondary winding 72 is wound. The first core 73 is on the charging device side, the second core 74 is on the liquid level measuring device side, and the first core 73 and the second core 74 are mounted by attaching the liquid level measuring device to the charging device. Are in contact or close to each other, and the primary winding 71 and the secondary winding 72 are magnetically coupled via these cores to form a transformer. In this way, electric power is transmitted from the primary winding 71 to the secondary winding 72 and converted into direct current via the charging circuit 6 as described with reference to FIG. 2 to charge the secondary battery of the built-in power supply 5. If the DC voltage generated by the DC power supply 50 does not match the charging voltage of the secondary battery, the turns ratio of the primary winding 71 and the secondary winding 72 can be set so as to be an appropriate charging voltage. Good.

1 Sensor 2 Tank information input section (Code setting switch)
3 Wireless transceiver 4 Barrier circuit 5 Built-in power supply 6 Charging circuit 7 Power relay unit (transformer)
DESCRIPTION OF SYMBOLS 10 Housing 11 Sensor mounting base 14 Guard plate 15 Planar antenna

Claims (8)

A liquid level measuring device for measuring a liquid level of a liquid stored in a tank for storing the liquid,
A sensor for detecting the liquid level without contacting the liquid;
A wireless transceiver that transmits a liquid level signal detected by the sensor to the outside;
A built-in power supply for supplying power for driving the sensor and the wireless transceiver;
A housing that houses the sensor, the wireless transceiver, and the built-in power supply in a sealed space;
The housing is detachably provided on an upper part of the tank provided in plural,
Each of the tanks has a tank information input unit that inputs an identification signal of the individual tank to the wireless transceiver by mounting the housing.
The wireless transceiver transmits the liquid level signal together with the tank identification signal.   The liquid level measuring device according to claim 1, wherein the built-in power source is a secondary battery and is charged from an external power source through a power relay unit.   The power relay unit is composed of a transformer, and is configured so that power is relayed from the AC external power source into the housing by magnetic coupling by the core of the transformer. The liquid level measuring device according to claim 2, wherein a charging circuit for charging the battery is provided.   A part of the core of the transformer is provided on the housing side, and another part of the core of the transformer is provided on the charging device side. By attaching the housing removed from the tank to the charging device, the core of the transformer is provided. 4. The liquid level measuring device according to claim 3, wherein the liquid level measuring device is configured such that a part and the other part of the core of the transformer are magnetically coupled.   The liquid level measuring device according to claim 1, wherein a barrier circuit for suppressing excessive voltage and current is provided in a power supply circuit extending from the built-in power source to the sensor and the wireless transceiver.   The housing mounting portion to the tank and the tank receiving portion to which the mounting portion is mounted are provided with flanges, and have flanges that tighten the periphery of both flanges so that the flanges are in close contact with each other. The liquid level measuring device according to claim 1.   2. The liquid level measuring device according to claim 1, wherein a protection plate for sealing the inner space of the tank is fixed to a receiving portion of the tank to which the housing is attached.   The liquid level measuring device according to claim 7, wherein the protection plate is made of a material that transmits radio waves, and the sensor is a radio wave type level gauge.

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