JP2006284523A - Device for measuring pressure of pressurized container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring pressure of a pressurized container, which properly measures fluid pressure. <P>SOLUTION: The device 4 for measuring the pressure of the pressurized container 1, which properly measures the pressure of fluid stored in the container 1, is provided with a deriving means for deriving acoustic impedance of the fluid by propagating acoustic waves in the container 1. The deriving means has a wave-transmitting unit 21, a wave-receiving unit 22, and an acoustic impedance calculating section 32. A pressure calculating section 33 calculates the fluid pressure, from the acoustic impedance of the fluid calculated by the acoustic impedance calculating section 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure measuring device for a pressure vessel that measures the pressure of a fluid stored in the pressure vessel.

  A high pressure gas is stored in a pressure vessel mounted on a fuel cell vehicle or the like. For example, natural gas of 20 MPa and hydrogen gas of 35 MPa or 70 MPa are stored in the pressure vessel. When the filling amount of the gas in the pressure vessel decreases due to traveling of the fuel cell vehicle or the like, the pressure of the gas in the pressure vessel decreases.

In general, a pressure sensor is attached to the pressure vessel, and the filling amount of the gas in the pressure vessel is measured based on the detection result of the pressure sensor, or the full filling determination at the time of filling is performed. As this type of pressure measuring apparatus, there is known one in which a plurality of strain gauge type pressure sensors are prepared corresponding to the measurement area (for example, see Patent Document 1).
Japanese Patent Laying-Open No. 2003-270073 (FIG. 2)

  Such a conventional pressure measuring device is useful in that the gas pressure can be measured in a wide range. However, since a plurality of pressure sensors are required, the cost is likely to increase.

  An object of the present invention is to provide a pressure measuring device for a pressure vessel that can appropriately measure the pressure of a fluid.

  The pressure vessel pressure measuring device of the present invention is a pressure vessel pressure measuring device for measuring the pressure of a fluid stored in the pressure vessel, and the acoustic impedance of the fluid is derived by propagating sound waves in the pressure vessel. And derivation means for calculating the pressure of the fluid from the acoustic impedance derived by the derivation means.

  According to this configuration, first, the acoustic impedance of the fluid is derived, and then the pressure of the fluid is calculated from the acoustic impedance using the fact that the acoustic impedance is proportional to the density of the fluid. Thereby, the pressure of the fluid can be measured appropriately without providing a plurality of pressure sensors in the pressure vessel. In addition, it is preferable to improve the directivity of a sound wave by propagating an ultrasonic wave.

  In this case, the derivation means includes a transmitter that transmits a sound wave into the pressure vessel, a receiver that receives the sound wave transmitted from the transmitter, and an acoustic impedance of the fluid based on a reception result of the receiver. It is preferable that at least one of the transmitter and the receiver is provided in the pressure vessel at the longitudinal end of the pressure vessel.

  According to this configuration, for example, when an opening that communicates the inside and the outside of the pressure vessel is provided at an end portion in the longitudinal direction of the pressure vessel, the transmitter and / or the receiving wave are utilized using the opening. A vessel can be provided inside the pressure vessel. Thereby, a transmitter and / or a receiver can be simply provided inside the pressure vessel.

  In this case, it is preferable that the transmitter and the receiver are provided in one end of the pressure vessel in the longitudinal direction in the pressure vessel.

  According to this configuration, for example, a sound wave transmitted from one end side in the longitudinal direction of the pressure vessel can be reflected on the other end side in the longitudinal direction of the pressure vessel. As a result, a sound wave path can be secured at least twice as long as the pressure vessel, and the accuracy of acoustic impedance derivation can be improved.

  In these cases, it is further provided with a guide reflection unit that is provided inside the pressure vessel and reflects a sound wave transmitted from the transmitter to guide it to the receiver, and the guide reflection unit includes the transmitter and the receiver. It is preferable to have a parabolic shape with at least one focus.

  According to this configuration, the directivity of the sound wave can be improved when the guide reflection unit has a parabolic shape with the transmitter as a focal point. On the other hand, in the case of a parabolic shape with the receiver as a focal point, the sound wave can be focused. As described above, by providing the guide reflection portion, it is possible to suppress irregular reflection of sound waves, and thus it is possible to measure the pressure of the fluid with higher accuracy.

  In this case, it is preferable that the parabolic shape of the induction reflecting portion is constituted by the inner wall of the pressure vessel.

  According to this configuration, it is not necessary to provide a parabolic guide reflection portion as a separate body on the inner wall of the pressure vessel.

  In these cases, it is preferable to further include a substantially cylindrical member that is provided inside the pressure vessel and covers a path through which sound waves propagate from the transmitter to the receiver.

  According to this configuration, since the divergence of the sound wave can be suppressed by the substantially cylindrical member, the pressure of the fluid can be measured with higher accuracy.

  In this case, it is preferable that a sound absorbing material is provided on the inner wall of the substantially cylindrical member.

  According to this configuration, since the irregular reflection of the sound wave in the substantially cylindrical member can be suppressed, the pressure of the fluid can be measured with higher accuracy. The sound absorbing material may be a porous sound absorbing material such as glass wool, or a film type sound absorbing material such as plywood or a film.

  In this case, a temperature sensor for detecting the temperature of the fluid is further provided, and the calculation means calculates the density of the fluid based on the sound velocity calculated from the temperature detected by the temperature sensor and the acoustic impedance derived by the derivation means. It is preferable to calculate and to calculate the pressure of the fluid from the calculated density.

  According to this configuration, the temperature sensor that detects the temperature of the fluid in the pressure vessel is provided in consideration that the speed of sound is defined as a function of the temperature of the fluid. For this reason, when calculating the density of the fluid from the acoustic impedance and the sound velocity, the temperature of the fluid is taken into account as the value of the sound velocity, and the temperature is compensated. Thereby, the pressure of the fluid can be calculated more appropriately.

  According to the pressure measuring device for a pressure vessel of the present invention, since the method for deriving the acoustic impedance of the fluid in the pressure vessel is used, the pressure of the fluid can be appropriately measured.

  A pressure vessel pressure measuring device according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings. This pressure measuring device measures the pressure of a fluid stored in a pressure vessel using sound. In the following first embodiment, the structure of the pressure vessel will be described first, and then the pressure measuring device will be described. In the second and subsequent embodiments, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

<First Embodiment>
As shown in FIG. 1, the pressure vessel 1 measures a sealed cylindrical container body 2 as a whole, a base 3 attached to both ends in the longitudinal direction of the container body 2, and the pressure of the fluid in the container body 2. And a pressure measuring device 4. The inside of the container body 2 is a storage space 5 that stores fluids such as various gases and liquids. The pressure vessel 1 can be filled with a normal pressure fluid, or can be filled with a fluid whose pressure is higher than that of the normal pressure. That is, the pressure vessel 1 of the present invention can function as a high pressure tank.

  For example, in a fuel cell system, the fuel gas prepared in a high pressure state is decompressed and used for power generation of the fuel cell. The pressure vessel 1 of the present invention can be applied to store high-pressure fuel gas, and can store hydrogen gas as fuel gas, compressed natural gas (CNG gas), and the like. The pressure of the hydrogen gas filled in the pressure vessel 1 is, for example, 35 MPa or 70 MPa, and the pressure of the CNG gas is, for example, 20 MPa. Hereinafter, the pressure vessel 1 in which hydrogen gas is stored at a high pressure will be described as an example.

  The container body 2 has a two-layer structure of an inner liner 11 (inner shell) having gas barrier properties and a reinforcing layer 12 (outer shell) disposed on the outer periphery of the liner 11. The liner 11 is formed of a hard resin such as polyethylene, but may of course be formed of a metal such as aluminum. The reinforcing layer 12 is made of, for example, FRP containing carbon fiber and an epoxy resin, and is wound around so as to cover the outer surface of the liner 11.

  The base 3 is made of a metal such as stainless steel, for example, and is provided at the center of the hemispherical end wall portion 52 of the container body 2. The opening of the base 3 is configured to be able to be screwed in and connected to a functional part such as a valve assembly in which piping elements such as valves and joints are integrated. A valve assembly 14 is screwed into one base 3 of the present embodiment. A plug 15 is screwed to the other base 3. In FIG. 1, the valve assembly 14 and the plug 15 are indicated by a two-dot chain line.

  For example, the pressure vessel 1 on the fuel cell system is connected between the storage space 5 and an external gas flow path (not shown) via the valve assembly 14. In the pressure vessel 1, for example, hydrogen gas is filled in the storage space 5 and, for example, hydrogen gas is released from the storage space 5 through the valve assembly 14 and the gas flow path. In addition, although the nozzle | cap | die 3,3 was provided in the both ends of the pressure vessel 1, of course, the nozzle | cap | die 3 may be provided only in one edge part, and the stopper 15 may be abbreviate | omitted.

  The pressure measuring device 4 measures the pressure of the hydrogen gas (that is, the internal pressure of the container) serving as a medium in the storage space 5 using sound. The pressure measuring device 4 includes a transmitter 21 incorporated in the valve assembly 14, a receiver 22 incorporated in the stopper 15, and a control device 23 that performs overall control of the transmitter 21 and the receiver 22. (ECU). The wave transmitter 21 and the wave receiver 22 are spaced apart from each other in the longitudinal direction of the pressure vessel 1.

  The transmitter 21 functions as a sound source and transmits ultrasonic waves into the storage space 5. The transmitter 21 emits ultrasonic waves toward the receiver 22 in parallel to the axial direction that is the longitudinal direction of the pressure vessel 1. The wave receiver 22 receives the ultrasonic wave transmitted from the wave transmitter 21.

  The transmitter 21 and the receiver 22 may be installed in the pressure vessel 1 without being incorporated in the valve assembly 14 and the plug 15. Further, the transmitter 21 or the receiver 22 may be configured to transmit or receive sound waves in a frequency range that is out of the ultrasonic frequency range. However, by using ultrasonic waves, the directivity of the sound waves can be improved and the influence of surrounding interference and the like can be reduced. Furthermore, as a method for generating ultrasonic waves, a known method can be applied. For example, a vibrator such as a crystal or a piezoelectric element may be used.

  Although not shown, the control device 23 includes a CPU, a ROM storing a control program and control data processed by the CPU, a RAM mainly used as various work areas for control processing, and an input / output interface. These are connected to each other via a bus. The control device 23 includes a pulse generation unit 31, an acoustic impedance calculation unit 32, and a pressure calculation unit 33 as processing units that execute the function of the pressure measurement device 4 of the present embodiment.

The pulse generator 31 generates a pulse signal for the transmitter 21 to transmit an ultrasonic wave. The generated pulse signal is input to the transmitter 21.
The reception result of the receiver 22 is input to the acoustic impedance calculator 32. The acoustic impedance calculator 32 calculates the acoustic impedance of the hydrogen gas in the storage space 5 according to a predetermined algorithm based on the reception result of the receiver 22. The acoustic impedance Z ₀ of the hydrogen gas is expressed by the following equation (1), where ρ is the density of the hydrogen gas in the storage space 5 and C is the sound velocity thereof;
Z ₀ = ρC (1)

The acoustic impedance calculator 32, the transmitter 21 and the receiver 22 constitute a derivation means for deriving the acoustic impedance Z ₀ of hydrogen gas by propagating ultrasonic waves into the storage space 5. The calculation result by the acoustic impedance calculation unit 32 of this derivation means is output to the pressure calculation unit 33.

The pressure calculation unit 33 calculates the pressure of the hydrogen gas in the storage space 5 from the acoustic impedance Z ₀ of the hydrogen gas according to a predetermined algorithm. The pressure calculation unit 33 calculates the pressure of the hydrogen gas (internal pressure) using the fact that the acoustic impedance Z ₀ is proportional to the density of the hydrogen gas (see formula (1)). Normally, as the acoustic impedance value increases, the hydrogen gas pressure in the storage space 5 increases, and as the acoustic impedance value decreases, the hydrogen gas pressure in the storage space 5 decreases.

As described above, according to the pressure measuring device 4 of the present embodiment, the acoustic impedance Z ₀ of the hydrogen gas in the storage space 5 is derived, and the hydrogen gas pressure is calculated from the derived acoustic impedance Z ₀ . . Therefore, according to the pressure measuring device 4, it is possible to appropriately measure the pressure of the high-pressure hydrogen gas without providing a plurality of pressure sensors. This measurement result may be displayed on a display unit such as a panel indicating the state of the fuel cell system, or may be notified to a user or an operator by a notification unit such as a buzzer. In this case, although not shown, such a display unit and a notification unit may be connected to the pressure calculation unit 33.

Second Embodiment
Next, with reference to FIG. 2, the pressure measuring device 4 according to the second embodiment will be described focusing on the differences. The difference from the first embodiment is that a sound absorbing material 41 is provided on the inner wall of the liner 11 of the pressure vessel 1.

  The sound absorbing material 41 absorbs acoustic energy of ultrasonic waves radiated from the transmitter 21. A known material can be applied to the sound absorbing material 41. For example, the sound absorbing material 41 can be composed of a porous sound absorbing material such as glass wool or rock wool, or a film type sound absorbing material that attenuates sound by vibration of the film. The sound absorbing material 41 shown in FIG. 2 is provided on the inner wall of the body portion 51 of the container body 2, but may also be provided on the inner walls of the end wall portions 52 that are both ends of the container body 2.

  The point in which this embodiment becomes useful compared with 1st Embodiment is that the irregular reflection of the ultrasonic wave radiated | emitted from the transmitter 21 can be suppressed with the sound-absorbing material 41. FIG. Thereby, the noise of the ultrasonic wave received by the receiver 22 is reduced. For this reason, the pressure measuring device 4 can finally measure the pressure of the hydrogen gas in the storage space 5 with higher accuracy.

<Third Embodiment>
Next, with reference to FIG. 3, the pressure measuring device 4 according to the third embodiment will be described focusing on the differences. The difference from the first embodiment is that a pair of cylindrical members 61 and 62 are provided inside the pressure vessel 1.

  One cylindrical member 61 is, for example, a cylindrical member having both ends opened, and is attached to the end of the valve assembly 14. The other cylindrical member 62 is, for example, a cylindrical member having both ends opened, and is attached to the end of the plug 15. The pair of cylindrical members 61 and 62 are formed with an outer diameter smaller than the inner diameter of the opening of the base 3. A pair of cylindrical members 61 and 62 are formed, for example with metals, such as aluminum.

  The pair of cylindrical members 61 and 62 are positioned in the storage space 5 while being separated from each other by a predetermined distance in a state in which the respective axial directions coincide with each other and the respective opening end faces face each other. In addition, the pair of cylindrical members 61 and 62 are positioned so as to cover a path through which ultrasonic waves propagate from the transmitter 21 to the receiver 22. That is, a linear path through which the ultrasonic wave propagates is defined inside each of the cylindrical members 61 and 62.

  The point in which this embodiment becomes useful compared with 1st Embodiment is that the divergence of an ultrasonic wave can be suppressed with a pair of cylindrical members 61 and 62. FIG. Thereby, the noise of the ultrasonic wave received by the receiver 22 is reduced. For this reason, the pressure measuring device 4 can finally measure the pressure of the hydrogen gas in the storage space 5 with higher accuracy.

  In addition, although a pair of cylindrical member 61,62 was spaced apart and the inside of each cylindrical member 61,62 was connected to the storage space 5, the structure of a cylindrical member is not restricted to this. For example, the cylindrical members (61, 62) are formed of a single member, and the length of the cylindrical member (61, 62) in the axial direction is set to the ultrasonic wave from the transmitter 21 to the receiver 22. You may make it respond | correspond to the path | route to propagate. In this case, a communicating portion such as a hole, a groove or a slit for communicating with the storage space 5 may be provided on, for example, the peripheral surface of the cylindrical member (61, 62).

  Further, the sound absorbing material 41 described in the second embodiment may be provided on the inner wall surface of each of the cylindrical members 61 and 62. By doing so, irregular reflection of ultrasonic waves propagating through the respective cylindrical members 61 and 62 can be suppressed by the sound absorbing material 41, and the measurement accuracy of the pressure of hydrogen gas can be further enhanced.

<Fourth embodiment>
Next, with reference to FIG. 4, the pressure measuring device 4 according to the fourth embodiment will be described focusing on the differences. The difference from the first embodiment is that the wave receiver 22 is provided on the same side as the wave transmitter 21 and that the reflecting material 71 is provided at a position facing the wave transmitter 21 and the wave receiver 22. is there.

For example, the transmitter 21 and the receiver 22 are incorporated in the valve assembly 14. On the other hand, the reflecting material 71 is attached to, for example, an end portion facing the storage space 5 of the stopper 15. The reflective material 71 can be formed in a plate shape or a film shape. The reflective material 71 may be made of a material having an acoustic impedance different from the acoustic impedance Z _{0 of} hydrogen gas. The reflector 71 reflects the ultrasonic wave transmitted from the transmitter 21 toward the receiver 22.

The point that this embodiment becomes useful compared with the first embodiment is that the transmitter 21 and the receiver 22 can be centrally arranged, so that these can be simplified as a transmitter / receiver. . Further, since the ultrasonic wave is reflected by the reflecting material 71, it is useful in that the path through which the ultrasonic wave propagates is twice that of the first embodiment. As a result, a long ultrasonic path can be secured, and the accuracy of deriving the acoustic impedance Z ₀ of hydrogen gas can be improved.

  Further, when the stopper 15 is not provided, that is, when one end wall portion 52 of the container body 2 is configured as a closed end, and when the base 3 is not provided there, the reflective material 71 is provided on the inner surface of the end wall portion 52. Can be attached. In such a case, the manufacturing process of the container body 2 can be simplified and the number of parts can be reduced. Also in this embodiment, the sound absorbing material 41 shown in FIG. 2 may be provided on the inner wall of the container body 2. A pair of cylindrical members 61 and 62 shown in FIG. 3 may be provided in the storage space 5.

<Fifth Embodiment>
Next, with reference to FIG. 5, the pressure measuring device 4 according to the fifth embodiment will be described focusing on the differences. The difference from the second embodiment is that a guide reflection unit 81 and a guide reflection unit 82 that reflect ultrasonic waves are provided in the vicinity of the transmitter 21 and the receiver 22.

The guided reflection portion 81 on the side of the transmitter 21 is located between the transmitter 21 and the end wall portion 52 of the container body 2 and has a parabolic shape with the transmitter 21 as a focal point. The guide reflection portion 81 can be formed in a plate shape or a film shape. Material guide reflection portion 81 may be a material having a different acoustic impedance acoustic impedance Z ₀ of the hydrogen gas may be a metal such as aluminum. The guide reflection unit 81 reflects the sound wave transmitted from the transmitter 21 toward the guide reflection unit 82 on the receiver side.

The guided reflection part 82 on the receiver 22 side is located between the receiver 22 and the end wall 52 of the container body 2 and has a parabolic shape with the receiver 22 as a focal point. The guide reflection portion 82 can be formed in a plate shape or a film shape. The material of the guide reflection part 82 may be a material having an acoustic impedance different from the acoustic impedance Z _{0 of} hydrogen gas. For example, the guide reflection part 82 may be made of the same material as the guide reflection part 81 on the transmitter 21 side. The guide reflection unit 82 reflects the sound wave transmitted from the transmitter 21 and guides it to the receiver 22.

  According to the present embodiment, the directivity of ultrasonic waves is enhanced by the guide reflection unit 81 provided on the transmitter 21 side. For this reason, the irregular reflection of an ultrasonic wave can be suppressed and the noise in the receiver 22 can be reduced. Further, the ultrasonic wave is focused on the receiver 22 by the guide reflection portion 82 provided on the receiver 22 side. For this reason, the sound pressure level at the receiver 22 can be increased, and the signal can be increased. Therefore, according to the configuration of the present embodiment, it is possible to suppress noise due to irregular reflection of ultrasonic waves and measure the pressure of hydrogen gas more accurately than in the second embodiment.

  In addition, although the two induction | reflection reflection parts 81 and 82 were provided, the structure of only one of the induction reflection parts may be sufficient. Moreover, you may make it provide a guide reflection part (81, 82) by making the inner wall of the end wall part 52 of the container main body 2 into a parabola shape. By doing so, it is not necessary to separately provide plate-like or film-like guided reflection portions (81, 82) in the container body 2. The position of the sound absorbing material 41 provided on the inner wall of the container body 2 may be the inner wall of the body 51 of the container body 2 between the two guide reflection parts 81 and 82, but is not limited to this position. Absent.

  Next, referring to FIG. 6, a simplified diagram illustrating a process of installing the transmitter 21 and the guide reflection unit 81 in the pressure vessel 1. The transmitter 21 and the guide reflector 81 are assembled in advance in the valve assembly 14. The transmitter 21 is located on the distal end side of the valve assembly 14. The guide reflection portion 81 is attached to the valve assembly 14 so as to be foldable and unfoldable with respect to the side portion.

  When the transmitter 21 and the guide reflector 81 are installed in the pressure vessel 1, the guide reflector 81 is folded (closed) with respect to the side of the valve assembly 14, as shown in FIG. In this state, the valve assembly 14 is screwed into the base 3 and connected. After the completion of the screw connection, as shown in FIG. 6B, the guide reflection portion 81 is in a developed state (open state). This unfolding operation can be performed by an operator applying a force to a unfolding unillustrated mechanism, whereby the main part of the guide reflection portion 81 is separated from the side of the valve assembly 14.

  In addition, also when installing the wave receiver 22 and the guide reflection part 82 in the pressure vessel 1, it can carry out similarly to the above by assembling the wave receiver 22 and the guide reflection part 82 to the stopper 15 beforehand. it can.

  Further, instead of the installation method shown in FIGS. 5 and 6, the liner 11 and the guide reflection portion 81 of the container body 2 may be integrally formed. For example, when the liner 11 itself of the container body 2 is configured by joining together a pair of liner segments that have been divided and molded in advance, the guide reflector 81 is integrally formed when the liner segment is injection molded. Make it.

  Specifically, after providing the guide reflection portion 81 on the outside of the core, the core is put into the outer mold, and the molten resin for the liner split is injected into the outer mold. And the guide reflection part 81 is integrally molded. In this case, when the sound absorbing material 41 is provided on the inner wall of the liner split body, the sound absorbing material 41 is also preferably provided outside the core. The base 3 may also be insert-molded into the liner split. And this injection molding is performed about the two liner divisions and the guidance reflection part 81, and the edge parts of a liner division are joined after that. Finally, the pressure vessel 1 is manufactured by providing the reinforcing layer 12 on the outer surface of the liner 11 by the FW method.

<Sixth Embodiment>
Next, with reference to FIG. 7, the pressure measuring device 4 according to the sixth embodiment will be described focusing on the differences. The difference from the first embodiment is that the temperature sensor 91 is provided and that the detection result obtained by the temperature sensor 91 is used when calculating the pressure of the hydrogen gas to compensate for the temperature.

  The temperature sensor 91 detects the temperature of the hydrogen gas in the storage space 5 and is incorporated in the valve assembly 14, for example. The detection result of the temperature sensor 91 is input to the pressure calculation unit 33 of the control device 23.

As in the above formula (1), the acoustic impedance Z ₀ of hydrogen gas is represented by ρC. Here, the sound velocity C of hydrogen gas is defined as a function of the temperature of hydrogen gas, as is well known. Therefore, when calculating the density ρ from the above equation (1), it is preferable to use the value of the sound velocity C based on the temperature of the hydrogen gas in the storage space 5.

Therefore, when calculating the density ρ from the acoustic impedance Z ₀ that is the calculation result of the acoustic impedance calculation unit 32, the pressure calculation unit 33 of the present embodiment is a value derived from the detection result of the temperature sensor 91 as the value of the sound velocity C. Is used. As a result, the density ρ is temperature compensated. Therefore, according to this embodiment, the pressure of hydrogen gas can be calculated more appropriately from the density ρ.

  The above-described pressure vessel 1 provided with the pressure measuring device 4 of the present invention is suitable for use in a vehicle equipped with a fuel cell system. Moreover, the pressure vessel 1 of the present invention can be suitably applied to a transportation system that uses a fluid stored in the pressure vessel 1 as a power source, such as an aircraft or a ship other than a vehicle.

It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 1st Embodiment. It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 2nd Embodiment. It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 3rd Embodiment. It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 4th Embodiment. It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 5th Embodiment. It is a figure which simplifies and demonstrates the process of installing the transducer of the pressure measuring device which concerns on 5th Embodiment. It is a figure which shows the structure of the pressure measuring device of the pressure vessel which concerns on 6th Embodiment.

Explanation of symbols

1 pressure vessel, 4 pressure measuring device, 21 transmitter, 22 receiver, 23 control device,
32 acoustic impedance calculation unit, 33 pressure calculation unit, 41 sound absorbing material, 61 cylindrical member, 62 cylindrical member, 81 induction reflection unit, 82 induction reflection unit, 91 temperature sensor

Claims (8)

A pressure vessel pressure measuring device for measuring the pressure of a fluid stored in a pressure vessel,
Derivation means for deriving the acoustic impedance of the fluid by propagating sound waves in the pressure vessel;
Calculation means for calculating the pressure of the fluid from the acoustic impedance derived by the derivation means;
A pressure vessel pressure measuring device comprising: The derivation means includes
A transmitter for transmitting sound waves into the pressure vessel;
A receiver for receiving a sound wave transmitted from the transmitter;
Calculating means for calculating an acoustic impedance of the fluid based on a reception result of the receiver; and
The pressure measurement device for a pressure vessel according to claim 1, wherein at least one of the transmitter and the wave receiver is provided in an end portion of the pressure vessel in a longitudinal direction within the pressure vessel.   The pressure measuring device for a pressure vessel according to claim 2, wherein the wave transmitter and the wave receiving device are provided in one end portion in the longitudinal direction of the pressure vessel in the pressure vessel. A guide reflection unit provided inside the pressure vessel and configured to reflect a sound wave transmitted from the transmitter to guide the receiver;
4. The pressure measurement device for a pressure vessel according to claim 2, wherein the guide reflection section has a parabolic shape with at least one of the transmitter and the receiver as a focal point. 5.   The pressure vessel pressure measuring device according to claim 4, wherein the parabolic shape of the induction reflecting portion is configured by an inner wall of the pressure vessel.   6. The device according to claim 2, further comprising a substantially cylindrical member that is provided inside the pressure vessel and covers a path of propagation of sound waves from the transmitter to the receiver. Pressure vessel pressure measuring device.   The pressure measuring device for a pressure vessel according to claim 6, wherein a sound absorbing material is provided on an inner wall of the substantially cylindrical member. A temperature sensor for detecting the temperature of the fluid;
The calculation means calculates the density of the fluid based on the sound velocity calculated from the temperature detected by the temperature sensor and the acoustic impedance derived by the derivation means, and the fluid is calculated from the calculated density. The pressure measuring device for a pressure vessel according to any one of claims 1 to 7, wherein the pressure is calculated.

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