LIQUID DENSITY MEASURING DEVICE, SYSTEM, AND METHOD

Abstract

A probe assembly for determining the saturation pressure of a liquid includes a manifold having an internal passageway and an elongated sphere having a distal end portion and a proximal end portion and defining a chamber. The sphere is secured to the manifold at the proximal end portion, with the chamber in fluid communication with the internal passageway. A charging port is selectively in fluid communication with the internal passageway of the manifold. A pressure transmitter is configured to detect pressure within the chamber of the elongated sphere.

Description

[Technical field]

[0001]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 987,477, filed March 10, 2020, the contents of which are incorporated herein by reference.

[0002] The present invention relates generally to liquid supply and dispensing processes and systems, and more particularly to liquid density measurement devices, systems, and methods. [Background technology]

[0003]

[0003] Liquids that evaporate at or below ambient temperatures, such as cryogenic liquids, are used in many applications. Such liquids are typically stored in insulated containers and dispensed or dispensed for use by a use device or in an industrial process. Accurately metering and / or monitoring the flow rate of the liquid as it is dispensed or dispensed is important in many applications. In order to accurately meter and monitor the flow rate of the liquid, it is necessary to determine the density of the flowing liquid.

[0004]

[0004] Cryogenic liquids present challenges in measuring the density of flowing liquids because the temperature of the liquid is very low (cryogenic liquids boil at -90°C (-130°F)). For example, current technologies for measuring the density of flowing liquids include Resistance Temperature Devices (RTDs), which can experience operational problems at liquid hydrogen temperatures. Another technology currently used for measuring the density of flowing liquids, the Cryogenic Platinum probe, is not linear with hydrogen temperature and requires calibration, which is difficult and expensive.

[0005]

[0005] When the cryogenic liquid is flammable (such as in the case of hydrogen), additional challenges exist, especially when electrical components are used to measure the density of the flowing liquid due to electrical code requirements.

[0006]

[0006] Diode technology, an alternative technology, is very accurate but has packaging challenges.

[0007] Furthermore, many of the prior art technologies used for density measurement of flowing liquids are not robust. Summary of the Invention [Means for solving the problem]

[0007]

[0008] There are multiple aspects of the present subject matter that may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the joint description of these aspects is not intended to exclude the separate use of these aspects or to exclude claiming these aspects separately or in various combinations as set forth in the appended claims.

[0008]

[0009] In one aspect, a probe assembly for determining the saturation pressure of a liquid includes a manifold having an internal passage. The probe also includes an elongated sphere defining a chamber having a distal end portion and a proximal portion. The sphere is secured to the manifold at the proximal portion, with the chamber in fluid communication with the internal passage. A charging port is in selective fluid communication with the manifold. A pressure transmitter is configured to detect pressure within the chamber of the elongated sphere.

[0009]

[0010] In another aspect, a system for determining the saturation pressure of a liquid features a probe assembly having a manifold having an internal passageway and an elongated sphere defining a chamber having a distal end portion and a proximal portion. The sphere is secured to the manifold by the proximal portion, with the chamber containing pressurized steam. The chamber is also in fluid communication with the internal passageway. A charging port is in selective fluid communication with the manifold. A pressure transmitter is configured to detect pressure within the chamber of the elongated sphere. The system also features a jacketed pipe assembly having a pipe defining a flow passageway and a jacket surrounding the pipe to form a first annular space, the annular space being at least partially evacuated. The jacketed pipe assembly also has a probe port, and the probe assembly is attached to the probe port with a distal end portion of the sphere positioned within the flow passageway of the pipe.

[0010]

[0011] In another aspect, a method for determining a saturation pressure of a liquid in a passage includes placing an elongated bulb containing pressurized steam in the passage, where the steam and liquid are equal fluids, and sensing the pressure of the pressurized steam after the bulb is placed in the passage. [Brief description of the drawings]

[0011] [Figure 1]

[0012] FIG. 1A illustrates a side view of an embodiment of a probe assembly of the present disclosure and a cross-sectional view of a portion of a vacuum jacketed pipe assembly before liquid flows through the vacuum jacketed pipe assembly.

[0013] FIG. 1B is an enlarged cross-sectional view showing the interface of the probe assembly of FIG. 1A with the vacuum jacketed pipe assembly of FIG. 1A. [Diagram 2]

[0014] FIG. 2A is a side view of the probe assembly and vacuum jacketed pipe assembly of FIG. 1A, with the vacuum jacketed pipe assembly containing a liquid stream.

[0015] 2B is an enlarged cross-sectional view showing the interface of the probe assembly of FIG. 2A with the vacuum jacketed pipe assembly of FIG. 2A. [Diagram 3]

[0016] 1 is a graph showing density versus saturation pressure for liquid hydrogen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012]

[0017] An embodiment of a system for measuring the density of a flowing liquid is shown generally at 10 in Figures 1A and 2A. The system has a probe assembly, shown generally at 12 in Figures 1A and 2A. Although the embodiment is described below with reference to hydrogen as the flowing liquid, it should be understood that embodiments of the present disclosure may also be used to measure the density of other flowing liquids, including both cryogenic and non-cryogenic liquids.

[0013]

[0018] As shown in FIG. 1A, a probe 12 has an elongated bulb generally designated 14. The bulb has a distal end portion 16 and a proximal portion 18. The probe 12 also has a manifold 22 to which the proximal portion of the bulb is attached. A vent valve 24 is also attached to the manifold 22. The vent valve 24 may be, by way of example only, a burst disk valve. A charging valve 26 having a charging port 28 is also attached to the manifold, as is a pressure transmitter 32. The manifold 22 has internal passages that are in fluid communication with each other and with the bulb 14, the vent valve 24, the charging valve 26, and the charging port 28.

[0014]

[0019] A vacuum jacketed pipe assembly, portions of which are generally shown at 42 in Figures 1A and 2A, directs a stream of liquid from a source to a destination. By way of example only, the source may be a vacuum storage tank and the destination may be a use device or industrial process. The vacuum jacketed pipe assembly 42 features an inner pipe 44 surrounded by a jacket 46. An annular space 48 defined therebetween preferably contains a vacuum or near vacuum pressure level. The inner pipe has a flow path 50.

[0015]

[0020] A port is formed in the vacuum jacketed pipe assembly having an outer sleeve 52, an inner sleeve 53 (FIG. 1B), and an end cap fitting 54 with a central opening that leads to the port central bore (surrounded by the inner sleeve 53). The annular interior space 56 of the port between the inner sleeve 53 and the outer sleeve 52 is fluidly connected to the annular space 48 between the inner pipe 44 and the jacket 46. As a result, the port interior space 56 is also at vacuum or near vacuum level and is well insulated.

[0016]

[0021] As shown in FIGS. 1A and 1B, the probe assembly 12 is mounted within the vacuum jacketed pipe assembly 42 by inserting the ball into and through the central opening and central hole of the port of the end cap fitting 54 until the distal end portion 16 of the ball 14 of the probe assembly is positioned within the flow passage 50 of the vacuum jacketed pipe assembly 42.

[0017]

[0022] A mounting member 62 is provided on the manifold and engages the port end cap fitting 54 of the vacuum jacket pipe assembly such that the port assembly 12 is removably secured to the jacket pipe assembly 42. By way of example only, the mounting member 62 of the probe assembly and the end cap fitting 54 of the vacuum jacket pipe assembly may be threaded such that a threaded connection is formed.

[0018]

[0023] In an alternative embodiment, the probe may be permanently attached to the vacuum jacketed pipe assembly, with the bulb distal end portion 16 positioned within the flow passage 50 of the vacuum jacketed pipe assembly 42. Such an embodiment would eliminate the need for the outer sleeve (52) and inner sleeve (53) as well as the end cap fitting 54.

[0019]

[0024] 1B, bulb 14 has a pressurized bulb chamber 72. Bulb chamber 72 is fluidly connected to the passage of manifold 22 of FIG. 1A. In an embodiment where hydrogen is the liquid flowing through pipe passage 50, bulb chamber 72 contains hydrogen vapor. By way of example only, chamber 72 is pressurized to about 500 psi. In alternative embodiments, the bulb can have alternative vapors and pressures.

[0020]

[0025] The vapor in bulb chamber 72 is preferably matched to the liquid flowing through passage 50 (as in the embodiment shown in which chamber 72 has hydrogen vapor and liquid hydrogen flows through passage 50), although there may be embodiments in which different fluids may be used in chamber 72 and passage 50.

[0021]

[0026] Chamber 72 of bulb 14 may be charged with pressurized hydrogen vapor by connecting a source of pressurized hydrogen vapor to charging port 28 and opening charging valve 26. Once chamber 72 is filled with hydrogen vapor and reaches an appropriate pressure, valve 26 is closed and the source of pressurized hydrogen is disconnected from charging port 28.

[0022]

[0027] When the steam within the chamber 72 of the bulb 14 warms up and exceeds a predetermined pressure level, the safety valve 24 automatically opens to release the steam from the chamber to the atmosphere.

[0028] In FIG. 2A, a stream of pressurized liquid hydrogen 76 flows through the flow passage 50 of the vacuum jacketed pipe assembly 42. Thus, the distal end portion 16 of the bulb 14 of the probe assembly 10 is surrounded by cold hydrogen liquid 76. Referring to FIG. 2B, this causes some of the hydrogen vapor in the bulb chamber 72 to condense, resulting in condensed vapor 74 pooling or collecting at the bottom of the distal end portion 16. This reduces the pressure in the chamber 72 to a saturation pressure that corresponds to the temperature of the liquid hydrogen in the flow passage 50. As a result, the pressure in the chamber 72 matches the saturation pressure of the liquid hydrogen in the flow passage 50.

[0023]

[0029] The pressure in chamber 72 is sensed by pressure transmitter 32 (which also has pressure sensing capabilities) and communicated to a controller (not shown). The controller may include a microprocessor or other computing device. By way of example only, the pressure transmitter may receive power from an on-board battery or an external power source. Further, by way of example only, a suitable controller includes the FlowCom 3000 controller available from Flow Instruments & Engineering GmbH, Monheim, Germany. Pressure transmission may be by wireless or wired transmission.

[0024]

[0030] As known in the art and as shown in Figure 3, once the saturation pressure of a fluid such as liquid hydrogen is known, this liquid density versus saturation data can be utilized to determine the density of the liquid. Upon receiving pressure data from pressure transmitter 32, the controller is programmed to use a combination of polynomials and look-up tables to calculate the temperature and density of the liquid hydrogen stream in flow path 50. The controller can then display the fluid temperature and density to a user. Alternatively or additionally, the controller can use the received and calculated data to determine the flow rate of liquid hydrogen in flow path 50 using equations known in the art.

[0025]

[0031] In some embodiments, the saturation pressure may be used by the controller to first calculate the temperature (since the type of fluid is known), followed by a density calculation as a second step. The density calculation may optionally be combined with the line pressure in the flow passage 50 of the vacuum pipe assembly to account for the compressibility of the fluid. Such a system requires a second pressure transmitter, such as 32 in FIGS. 1A and 2A, to determine the pressure in the flow passage 50. There are multiple polynomials that allow the controller to calculate the fluid density based on the temperature at various pressures. Interpolation is then utilized to determine the density based on the accurate line pressure measurement. Alternatively, a look-up table may also be used as input data for the interpolation.

[0026]

[0032] It should be appreciated that the saturation pressure of the liquid hydrogen in the passage 50 of the vacuum pipe assembly 42 of Figures 2 and 2B may also be determined when the liquid hydrogen in the passage is in a static, non-flowing state.

[0033] By way of example only, and in view of the above, embodiments of the present disclosure may be useful in flowmeter designs for hydrogen environments. In addition, the above embodiments are rugged, field rechargeable, and utilize transmitter electrical classifications (Class 1 div 1 or div 2).

[0027]

[0034] While preferred embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications can be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims.

Claims

1. 1. A system for determining the saturation pressure of a liquid, comprising: a) a probe assembly, i. a manifold having an internal passage; ii. an elongated bulb having a distal end portion and a proximal portion and defining a chamber, said bulb being secured to said manifold by said proximal portion, wherein said chamber contains pressurized steam and is in fluid communication with said internal passage; iii. a charging port selectively in fluid communication with the interior passage of the manifold; and iv. a pressure transmitter configured to sense pressure within the chamber of the elongated sphere; a probe assembly having b) a clad pipe assembly, i. a pipe defining a flow path; ii. a jacket surrounding the pipe to form a first annular space, the annular space being at least partially evacuated; and iii. a probe port, the probe assembly being attached to the probe port, the probe port being configured to position the distal end portion of the bulb within the flow passage of the pipe. A coated pipe assembly having Equipped with The system wherein the liquid is liquid hydrogen and the pressurized vapor is pressurized hydrogen vapor.

2. 2. The system of claim 1, wherein the probe port comprises an inner sleeve defining a central hole configured to receive the elongated ball, an end cap fitting having a central opening configured to receive the elongated ball, and an outer sleeve surrounding the inner sleeve to define a second annular space between the inner sleeve and the outer sleeve and the end cap fitting, the second annular space being fluidly connected to the first annular space.

3. The system of claim 2 , wherein the probe assembly is removably attached to the end cap fitting.

4. 10. The system of claim 1, further comprising a controller, the pressure transmitter configured to communicate the detected pressure to the controller, and the controller configured to determine a temperature and density from the detected pressure.

5. 1. A method for determining a saturation pressure of a liquid in a passageway, comprising the steps of: a) placing an elongated bulb containing pressurized steam within said passageway, said steam and said liquid being equal fluids; b) detecting a pressure of the pressurized steam after the bulb is disposed within the passageway when the pressurized steam condenses and reaches the saturation pressure of the liquid; The method according to claim 1, wherein the fluid is hydrogen.

6. The method of claim 5 further comprising the step of communicating the detected pressure to a remote control device.

7. The method of claim 6 further comprising the step of calculating temperature and density using the sensed pressure and the controller.

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