(19)
(11)EP 2 277 019 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.06.2019 Bulletin 2019/26

(21)Application number: 09739692.3

(22)Date of filing:  29.04.2009
(51)International Patent Classification (IPC): 
G01F 25/00(2006.01)
(86)International application number:
PCT/US2009/042116
(87)International publication number:
WO 2009/134890 (05.11.2009 Gazette  2009/45)

(54)

APPARATUS AND METHOD FOR PROVING AT LOW TEMPERATURES

VORRICHTUNG UND VERFAHREN ZUR PRÜFUNG BEI NIEDRIGEN TEMPERATUREN

APPAREIL ET PROCEDE DE VERIFICATION A BASSE TEMPERATURE


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

(30)Priority: 30.04.2008 US 49110

(43)Date of publication of application:
26.01.2011 Bulletin 2011/04

(73)Proprietor: Daniel Measurement and Control, Inc.
Houston, Texas 77041 (US)

(72)Inventor:
  • DAY, Donald
    Cypress TX 77429 (US)

(74)Representative: Roberts, Peter David et al
Marks & Clerk LLP 1 New York Street
Manchester M1 4HD
Manchester M1 4HD (GB)


(56)References cited: : 
WO-A1-01/11213
WO-A1-93/15381
GB-A- 1 325 647
US-A- 5 251 489
US-A1- 2006 156 828
US-A1- 2007 234 778
WO-A1-84/02185
WO-A2-2007/130087
US-A- 3 580 045
US-A- 5 781 116
US-A1- 2007 169 536
US-A1- 2007 234 778
  
  • JONES E R ET AL: "Low temperature magnetic properties of F.C.C. Fe@?Cr@?Ni alloys: Effects of manganese and interstitial carbon and nitrogen", MATERIALS SCIENCE ENGINEERING, ELSEVIER SEQUOIA, LAUSANNE, CH, vol. 91, 1 July 1987 (1987-07-01), pages 181-188, XP025861633, ISSN: 0025-5416, DOI: 10.1016/0025-5416(87)90296-5 [retrieved on 1987-07-01]
  • K. M. Olsen ET AL: "Effect of Carbon Content on the Magnetic Properties of Iron-30% Cobalt-15% Chromium Alloys", Journal of Applied Physics, vol. 42, no. 4, 15 March 1971 (1971-03-15) , pages 1792-1793, XP055457873, US ISSN: 0021-8979, DOI: 10.1063/1.1660436
  • J.J. Gniewek ET AL: "Cryogenic behavior of selected magnetic materials", Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation, vol. 69C, no. 3, 1 July 1965 (1965-07-01), page 225, XP055457877, ISSN: 0022-4316, DOI: 10.6028/jres.069C.027
  • Tn 0302 ET AL: "Using Permanent Magnets at Low Temperatures", , 16 June 2003 (2003-06-16), XP055457880, Retrieved from the Internet: URL:http://spontaneousmaterials.com/Papers /TN_0302.pdf [retrieved on 2018-03-08]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND



[0001] After hydrocarbons have been removed from the ground, the fluid stream (such as crude oil or natural gas) is transported from place to place via pipelines. It is desirable to know with accuracy the amount of fluid flowing in the stream, and particular accuracy is demanded when the fluid is changing hands, or "custody transfer." Custody transfer can occur at a fluid fiscal transfer measurement station or skid, which may include key transfer components such as a measurement device or flow meter, a proving device, associated pipes and valves, and electrical controls. Measurement of the fluid stream flowing through the overall delivery pipeline system starts with the flow meter, which may include a turbine meter, a positive displacement meter, an ultrasonic meter, a coriolis meter or a vortex meter.

[0002] Flow characteristics of the fluid stream can change during product delivery that can affect accurate measurement of the product being delivered. Typically, changes of pressure, temperature and flow rate are acknowledged by operator intervention. These changes are represented as changes in the flow characteristics, and are normally verified by the operator via the effects of the changes and their effect on the measurement device. Normally, this verification is conducted by proving the meter with a proving device, or prover. A calibrated prover, adjacent the measurement device on the skid and in fluid communication with the measurement device, is sampled and the sampled volumes are compared to the throughput volumes of the measurement device. If there are statistically important differences between the compared volumes, the throughput volume of the measurement device is adjusted to reflect the actual flowing volume as identified by the prover.

[0003] The prover has a precisely known volume which is calibrated to known and accepted standards of accuracy, such as those prescribed by the American Petroleum Institute (API) or the internationally accepted ISO standards. The precisely known volume of the prover can be defined as the volume of product between two detector switches that is displaced by the passage of a displacer, such as an elastomeric sphere or a piston. The known volume that is displaced by the prover is compared to the throughput volume of the meter. If the comparison yields a volumetric differential of zero or an acceptable variation therefrom, the flow meter is then said to be accurate within the limits of allowed tolerances. If the volumetric differential exceeds the limits allowed, then evidence is provided indicating that the flow meter may not be accurate. Then, the meter throughput volume can be adjusted to reflect the actual flowing volume as identified by the prover. The adjustment may be made with a meter correction factor.

[0004] One type of meter is a pulse output meter, which may include a turbine meter, a positive displacement meter, an ultrasonic meter, a coriolis meter or a vortex meter. By way of example, Figure 1 illustrates a system 10 for proving a meter 12, such as a turbine meter. A turbine meter, based on turning of a turbine-like structure within the fluid stream 11, generates electrical pulses 15 where each pulse is proportional to a volume, and the rate of pulses proportional to the volumetric flow rate. The meter 12 volume can be related to a prover 20 volume by flowing a displacer in the prover 20. Generally, the displacer is forced first past an upstream detector 16 then a downstream detector 18 in the prover 20. The volume between detectors 16, 18 is a calibrated prover volume The flowing displacer first actuates or trips the detector 16 such that a start time t16 is indicated to a processor or computer 26. The processor 26 then collects pulses 15 from the meter 12 via signal line 14. The flowing displacer finally trips the detector 18 to indicate a stop time t18 and thereby a series 17 of collected pulses 15 for a single pass of the displacer. The number 17 of pulses 15 generated by the turbine meter 12 during the single displacer pass through the calibrated prover volume is indicative of the volume measured by the meter during the time t16 to time t18. By comparing the prover volume to the volume measured by the meter, the meter may be corrected for volume throughput as defined by the prover.

[0005] Figure 2 illustrates another system 50 for proving an ultrasonic flow meter 52, using transit time technology. The system 50 also includes a prover 20 and a processor 26. By ultrasonic it is meant that ultrasonic signals are sent back and forth across the fluid stream 51, and based on various characteristics of the ultrasonic signals a fluid flow may be calculated. Ultrasonic meters generate flow rate data in batches where each batch comprises many sets of ultrasonic signals sent back and forth across the fluid, and thus where each batch spans a period of time (e.g., one second). The flow rate determined by the meter corresponds to an average flow rate over the batch time period rather than a flow rate at a particular point in time.

[0006] In a particular embodiment of the prover 20, and with reference to Figure 3, a piston or compact prover is shown. A piston 102 is reciprocally disposed in a flow tube 104. A pipe 120 communicates a flow 106 from a primary pipeline to an inlet 122 of the flow tube 104. The flow 108 of the fluid forces the piston 102 through the flow tube 104, and the flow eventually exits the flow tube 104 through an outlet 124. The flow tube 104 and the piston 102 may also be connected to other components, such as a spring plenum 116 that may have a biasing spring for a poppet valve in the piston 102. A chamber 118 may also be connected to the flow tube 104 and the piston 102 having optical switches for detecting the position of the piston 102 in the flow tube 104. A hydraulic pump and motor 110 is also shown coupled to the flow line 120 and the plenum 116. A hydraulic reservoir 112, a control valve 114 and a hydraulic pressure line 126 are also shown coupled to the plenum 116. As will be shown below, the piston 102 can be adapted according to the principles taught herein.

[0007] In some applications, the fluids flowing in the pipelines (primary pipelines and those of the measurement station) are maintained at low temperatures. As used herein, low temperatures, for example, are generally less than about -45.6 °C (-50° F), alternatively less than about -51.1 °C (-60° F), alternatively less than about -140 °C (-220° F), and alternatively less than about -156.7 °C (-250° F). These low temperatures may also be referred to as very low temperatures or cryogenic temperatures. Examples of fluids maintained at low temperatures include liquid natural gas (LNG), liquefied petroleum gas (LPG) and liquid nitrogen. Low temperatures of the metered fluids cause numerous problems, such as unsuitability of the prover's sensing devices, wear on components such as seals, and reduced lubrication on the flow tube's inner surface for the low temperature fluids, which tend to be non-lubricating. Carbon steel reacts negatively to low temperature product flowing in the pipeline.

[0008] To address these problems, meters operating in very low temperatures are proved by indirect proving methods. Generally, indirect proving is accomplished by proving a meter suitable for very low temperature service using a prover that is not rated for very low temperature service. First, a fluid, generally water, is flowed through a proving meter, and the proving meter is proved in the normal way to establish a meter factor for the proving meter. The proving meter is then used on actual flowing low temperature product to obtain the meter factor for the meter measuring the low temperature product. Consequently, the proving meter is calibrated using a fluid unlike the actual product delivered through the meter (at least with regard to density), leading to incorrect results in the actual product meter to be calibrated.

[0009] Thus, there is a need for a prover adapted for very low temperatures, at least to increase durability of the prover and to provide direct proving of very low temperature products.

[0010] US3580046 discloses a bidirectional meter prover adapted to be connected to a conduit having a meter arranged therein. The bidirectional meter is provided with a valve means connected to the calibration barrel of the meter prover and to the meter such that the valve means is rapidly shifted for movement of the piston in the meter prover in either direction in the calibration barrel for proving the meter. The meter prover is adapted for proving meters used for metering cryogenic liquids with the cryogenic liquid being introduced into the meter proving system and with the cryogenic liquid being vented as the system is cooled to equilibrium temperature; venting is stopped while introduction of cryogenic liquid is continued until thermal equilibrium is reached. Thereafter, the system is operated to prove the meter at equilibrium temperature.

BRIEF DESCRIPTION OF THE DRAWINGS



[0011] For a detailed description of exemplary embodiments, reference will now be made to the accompanying drawings in which:

Figure 1 is a schematic representation of a system for proving a meter, such as a turbine

Figure 2 is a schematic representation of another system for proving a meter, such as an ultrasonic meter;

Figure 3 is a schematic representation of a bi-directional piston-type prover;

Figure 4 is a piston according to the invention in accordance with the teachings herein;

Figure 5 is a side view of the piston of Figure 4;

Figure 6 is a cross-section view of the piston of Figures 4 and 5;

Figure 7 is a schematic of a piston in a prover flow tube according to the invention in accordance with the teachings herein; and

Figure 8 is a schematic of an alternative embodiment of the piston and prover of Figure 7 according to the invention.


DETAILED DESCRIPTION



[0012] In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure as defined according to the appended claims.

[0013] Unless otherwise specified, in the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to ...". Any use of any form of the terms "connect", "engage", "couple", "attach", or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The term "fluid" may refer to a liquid or gas and is not solely related to any particular type of fluid such as hydrocarbons. The terms "pipe", "conduit", "line" or the like refers to any fluid transmission means. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.

[0014] The embodiments described herein include a prover, such as a piston-type pipe prover, that is adapted for use with low temperature fluids at low temperatures less than -45.6 °C (-50° F). More particularly, the prover is used with fluids at low temperatures less than -140 °C (-200° F). There is presented herein various combinations of components and principles which provide the cryogenic prover, or methods of direct proving of liquids at extremely low temperatures. For example, a sensing device in the prover is improved for low temperatures, such as by adjusting material components or replacing sensors. The surface finish of the inner surface of the flow tube is improved for lubricating non-lubrous LNG and LPG products. In further embodiments, a piston rotator is provided to prevent deterioration of piston seals.

[0015] Referring initially to Figure 3, the prover 100 may alternatively include a detection member or target ring 130, disposable at various locations along the axial length of the piston 102. The flow tube 104 includes a sensor 128, also disposable at various locations along the axial length of the flow tube 104, for detecting passage of the target ring 130. The target ring 130 is the trip instigator for entry into and exit from the calibrated measuring section of the flow tube 104 of the prover 100. At very low temperatures, proper communication between the sensor 128 and the target ring 130 is negatively affected due to, for example, the unsuitability of the detector 128 or the materials of the target ring 130 at very low temperatures.

[0016] Referring now to Figure 4, an embodiment of a prover piston 202 is shown. The piston 202 may be used in a variety of provers, such as prover 100. The piston 202 is especially suited for a bi-directional prover. The piston 202 includes a body 230 with ends 206, 208. A middle portion of the body 230 includes a ring 210 coupled thereto. An inner portion of the piston body 230 includes an inner surface 212 with a plate 214 extending therebetween, generally perpendicular to the longitudinal axis of the piston 202. A first set of vanes 216 extends from the plate 214. The vanes 216 generally extend perpendicular to the plate 214, but also at an angle to the plate 214 such that the vanes may receive a fluid acting on the plate 214 and redirect a force applied to the plate 214. The vanes 216 may also be referred to as volume-reducing vanes. The angle of the vanes relative to the plate 214 is variable. In some embodiments, a second set of vanes is similarly disposed on an opposite side of the plate 214 to effect the same functions in a bi-directional manner.

[0017] Referring briefly to Figure 5, a side view of the piston 202 is shown illustrating the body 230 having the ends 206, 208 and the ring 210.

[0018] In some embodiments, the ring 210 is the target ring associated with the piston 202 and comprises carbon-free materials. In exemplary embodiments, the ring 210 comprises high mu (µ) metal. In exemplary embodiments, the ring 210 comprises HYMU or HYMU 80 metal components. In exemplary embodiments, the ring 210 comprises various combinations of nickel, iron, copper and/or molybdenum. The attachment of the target ring 210 to the piston 202 is designed to allow expansion and contraction of the target ring 210 such that it can expand and contract yet maintain a constant physical relationship not exceeding one in ten thousand repeatability.

[0019] With reference to Figure 7, a flow tube 204 containing the piston 202 includes a magnetic pickup coil 232 mounted thereon. The piston 202 is moveably and reciprocally disposed in a flow passage 224 of the flow tube 204 such the piston 202 can pass the magnetic pickup coil 232 in a bi-directional manner. As the target ring 210 passes the pickup coil 232, the ring and coil communicate via the magnetic reluctance principle. The target ring 210 provides the magnetic force flux which is received by the pickup coil 232. The target ring 210 passes in a pre-determined proximity, referred to as the air gap, and causes a deflection in the existing magnetic field of the pickup coil 232. The change in reluctance of the resulting magnetic circuit generates a voltage pulse, which is then transmitted to a preamplifier. The preamplifier strengthens the signal, which is used to trigger a prover computer, such as those disclosed herein, to collect meter pulses from the meter which is being proven.

[0020] In another embodiment, and with reference to Figure 8, a sensing assembly comprising a pair of ultrasonic transceivers 328, 330 is mounted on a flow tube 304 of a piston or compact prover. The transceivers 328, 330 may also be referred to as ultrasonic speed of sound transceivers. A piston assembly 302 is bi-directionally moveable in a flow passage 324 of the flow tube 304. The transceivers 328, 330 communicate via a straight line sonic signal 332. When the leading edge of the piston 302, whether it be the end 306 or the end 308, aligns with the transceivers 328, 330, the signal 332 is interrupted. Interruption of the signal 332 triggers a prover computer, causing operation of the remainder of the prover and prover computer in the normal way and consistent with the teachings herein.

[0021] Still referring to Figures 7 and 8, the flow passages 224 and 324 include inner surfaces 226, 326, respectively. Typically, the prover flow tube or barrel comprises piping material well defined by applicable material specifications. The internal finish of the prover barrel, such as those on surfaces 226, 326, is normally graphite impregnated epoxy applied by conventional spray paint methodology. Due to the non-lubricity of certain hydrocarbon products to be proved, such as butanes, propanes and LPG's, the coating on the finished inner surfaces assists the displacer piston in moving smoothly through the prover barrel. This is a requirement for consistent and accurate proving. However, these coatings are not suitable for the lower temperatures defined herein. Thus, the surfaces 226, 326 of the embodiments of Figures 7 and 8 include a microfinish. The microfinish of the surfaces 226, 326 allows a microscopic film of product to be maintained at the surfaces 226, 326, thereby maximizing the already low degree of lubrication the product is able to inherently afford. In exemplary embodiments, the microfinishes applied to the surfaces 226, 326 include approximately 812.8 nm (32 microinch) to 406.4 nm (16 microinch) obtained by honing, milling or grinding.

[0022] Referring now to Figure 6, a cross-section taken along an axial length of the prover piston 202 is shown. The piston body 230 includes at its end 206 a first ring 240, a second ring 242 and a socket 244, primarily for assembly purposes. The rings 240, 242 provide alternative locations for the target ring as described herein to be disposed, in addition to the location described with respect to target ring 210. The first set of vanes 216 extends in a first direction from the plate 214, and a second set of vanes 246 extends in a second direction generally opposite the first direction to effect bi-directional movement of the piston 202. Further, the vanes 216, 246 are variably angled to provide the functions as described more fully below.

[0023] Generally, the displacer seals on the piston 202 provide a leak-proof barrier to prevent product from transitioning from one side of the piston 202 to the other. The seals can deteriorate based on two main causes. First, the friction of passage of the piston through the prover during normal operation can, over time, deteriorate the seal surface. The length of time to deterioration and seal failure is determined by frequency of use of the prover. The second factor that contributes to wear of the piston assembly is the gravitational forces on the seals caused by the weight of the piston. Focusing on this second factor can provide benefits.

[0024] Rotational movement of the piston about its axis, causing the piston 202 to spiral in the flow tube 204 as it is displaced, will reduce the wear factor and prolong the life of the piston seals. The rotational vanes 216, 246 provide the rotational or spiral movement of the piston 202. Introduction of flow perpendicular to the piston end will rotate the piston according to a variable angle A of the vanes. Stops may be put in the prover ends corresponding to the piston, and which are not encumbered by the vanes. The stops prevent the vanes from being distorted by the piston coming to rest at the end of the flow tube or prover barrel.

[0025] The teachings of the embodiments described herein may be employed in any suitable combination, as defined by the claims. The disclosure is not limited to the specific embodiments and combinations described herein; the invention being defined by the claims. The teachings herein include a direct meter proving method, such that fluid flowing to the meter is diverted directly to the prover despite the fluids being at very low temperatures that cannot be managed by current piston and compact provers. The fluid may be directed through the prover and then downstream to piping that re-introduces the product into the carrying pipeline. While not common, the prover sometimes is located upstream of the meter such that the flow is directed to the prover and then flows through the meter. The purpose of the prover is to provide a known volume to compare to an indicated metered volume. The two volumes are then standardized using correction factors for temperature, pressure and density parameters for the product to establish a meter factor. The meter factor is derived by dividing the volume of the fluid passing through the meter (determined by the prover volume while proving) by the corresponding meter-indicated volume. The prover volume is the volume displaced between the detector switches. The prover volume is established by precisely determining the volume between detector switches (also called the base volume of the prover) by a method called the waterdraw method, as described by the American Petroleum Institute.

[0026] Accuracy of a bidirectional piston-type pipe prover and the overall measurement station, when operating at temperatures of less than -45.6 °C (-50° F), and specifically at temperatures approximating -140 °C (-220° F), is significantly affected by limitations in component materials. A valve, such as a 4-way valve, is unavailable for very low temperatures and therefore renders other prover types inoperable for very low temperatures. The detector sensing ring and the detector devices in provers are unsuitable for low temperature service. Self-lubricating coatings for use with non-lubrous products such as LPG are unavailable for low temperature service. The embodiments described herein address these problems and others.

[0027] Exemplary embodiments of a flow meter prover for low temperature fluids include an inlet configured to be directly coupled to a pipeline carrying the low temperature fluids, an outlet configured to be directly coupled to the pipeline carrying the low temperature fluids, a flow tube coupled between the inlet and the outlet, and a displacer moveable in a flow passage of the flow tube and comprising a carbon-free magnetic member, wherein the flow tube and the displacer are configured to receive the low temperature fluids. The flow meter prover further includes a magnetic pickup coil and/or transceivers coupled to the flow tube and communicating with the displacer, wherein the flow passage includes an inner surface having a microfinish and wherein the prover is adapted for use with low temperature fluids having a temperature of less than about -45.6 °C (-50° F). In an embodiment, the carbon-free magnetic member is coupled to the displacer communicating with the magnetic pickup coil via magnetic reluctance. The displacer may be a piston and the carbon-free magnetic member may be a target ring wrapped around the piston. In another embodiment, the carbon-free target member is coupled to the displacer communicating with the magnetic pickup coil. The carbon-free target member may include at least one of high mu (µ) metal, HYMU metal, and HYMU 80 metal. The carbon-free target member may include a combination of nickel, iron, copper and/or molybdenum. In a further embodiment, the prover includes a pair of ultrasonic transceivers coupled to the flow tube and communicating a signal across the flow passage in the flow tube and wherein the displacer is moveable in the flow passage to interrupt the signal.

[0028] According to the invention, the flow passage of the prover includes an inner surface having a microfinish. The microfinish maintains a microscopic film of the low temperature fluids between the flow passage inner surface and the displacer for lubrication. The microfinish may be in the range of 812.8 nm (32 microinch) to 406.4 nm (16 microinch). The microfinish may be obtained by at least one of honing, milling, and grinding the inner surface. In other embodiments, the displacer includes a vane disposed at an angle relative to the flow direction of the low temperature fluids. The displacer may be a piston including a set of inner vanes extending along a longitudinal axis of the piston and set an angle relative to the axis. The vane rotates the displacer in response to the flow of the low temperature fluids.

[0029] Exemplary embodiments of a flow meter prover for low temperature fluids include a flow tube having a flow passage therein and a magnetic pickup coil mounted thereon and a piston disposed in the flow passage and including a carbon-free magnetic member, wherein the piston is moveable to move the magnetic member past the magnetic pickup coil and communicate with the magnetic pickup coil via magnetic reluctance. An inner surface of the flow passage includes a microfinish to maintain a microfilm of lubricating fluid. The piston includes a set of piston rotating vanes. In further embodiments, the prover includes a pair of ultrasonic transceivers disposed on the flow tube and communicating across the flow passage, and wherein the piston movement interrupts the ultrasonic transceiver communication.

[0030] Exemplary embodiments of a system for proving low temperature fluids include a pipeline carrying the low temperature fluids, a prover coupled into the pipeline and receiving the low temperature fluids, wherein the prover includes a flow tube including a piston moveably disposed therein and at least one of a magnetic pickup coil and a pair of ultrasonic transceivers coupled to the flow tube and communicating with the piston. The low temperature fluids include a temperature of less than about -45.6 °C (-50° F), and alternatively a temperature of less than about -140 °C (-220° F). The piston includes a carbon-free magnetic target member. An inner surface of the flow tube includes a microfinish to maintain a microfilm of lubricating fluid. The piston may be rotatable while being moved axially.

[0031] The above discussion is meant to be illustrative of the principles and various embodiments of the present disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims.


Claims

1. A flow meter prover comprising:

an inlet (122) configured to be directly coupled to a pipeline carrying low temperature fluids;

an outlet (124) configured to be directly coupled to the pipeline carrying the low temperature fluids;

a flow tube (104, 204, 304) coupled between the inlet (122) and the outlet (124);

a displacer (202, 302) moveable in a flow passage (224, 324) of the flow tube (104, 204, 304) and comprising a carbon-free magnetic member;

wherein the flow tube (104, 204, 304) and the displacer are configured to receive the low temperature fluids; and

a magnetic pickup coil (232) and/or a pair of transceivers (328, 330) coupled to the flow tube (104, 204, 304) and communicating with the displacer,

wherein the flow passage (224, 324) includes an inner surface (226, 326) having a microfinish and wherein the prover is adapted for use with low temperature fluids having a temperature of less than about -45.6 °C (-50° F).


 
2. The prover of claim 1 wherein the carbon-free magnetic member is coupled to the displacer and in communication with the magnetic pickup coil (232) via magnetic reluctance.
 
3. The prover of claim 2 wherein the displacer is a piston (202, 302) and the carbon-free magnetic member is a target ring (210) wrapped around the piston (202, 302).
 
4. The prover of claim 1, wherein the carbon-free magnetic member is coupled to the displacer and in communication with the magnetic pickup coil (232).
 
5. The prover of claim 4 wherein the carbon-free magnetic member comprises at least one of high mu (µ) metal, HYMU metal, and HYMU 80 metal.
 
6. The prover of claim 4, wherein the carbon-free magnetic member comprises a combination of nickel, iron, copper and/or molybdenum.
 
7. The prover of claim 1 wherein:

the pair of transceivers (328, 330) communicate a signal across the flow passage (324) in the flow tube (304); and

the displacer is moveable in the flow passage (324) to interrupt the signal.


 
8. The prover of claim 1, wherein the microfinish maintains a microscopic film of the low temperature fluids between the flow passage inner surface (226, 326) and the displacer for lubrication; or
wherein the microfinish is in the range of 812.8 nm (32 microinch) to 406.4 nm (16 microinch); or
wherein the microfinish is obtained by at least one of honing, milling, and grinding the inner surface.
 
9. The prover of claim 1 wherein the displacer includes a vane disposed at an angle relative to the flow direction of the low temperature fluids.
 
10. The prover of claim 9 wherein the displacer is a piston (202, 302) including a set of inner vanes (216, 246) extending along a longitudinal axis of the piston (202, 302) and set an angle relative to the axis; or
wherein the vane rotates the displacer in response to the flow of the low temperature fluids.
 
11. The prover of claim 1,
wherein the pair of transceivers (328, 330) comprises a pair of ultrasonic transceivers (328, 330); or
wherein the prover is adapted for use with low temperature fluids having a temperature of less than about -140°C (-220° F); or
wherein the prover is adapted for use with low temperature fluids having at least one of liquid natural gas (LNG), liquid nitrogen, liquid butane, liquid propane, and liquefied petroleum gas (LPG).
 
12. The prover of claim 1, wherein the displacer is a piston (202, 302) moveable to move the carbon-free magnetic member past the magnetic pickup coil (232) and communicate with the magnetic pickup coil (232) via magnetic reluctance.
 
13. The prover of claim 12 wherein the microfinish maintains a microfilm of lubricating fluid.
 
14. The prover of claim 12 wherein the piston (202, 302) includes a set of piston (202, 302) rotating vanes.
 
15. The prover of claim 12 further comprising:

a pair of ultrasonic transceivers (328, 330) disposed on the flow tube (104, 204, 304) and communicating across the flow passage (224, 324); and

wherein the piston (202, 302) movement interrupts the ultrasonic transceiver communication.


 


Ansprüche

1. Durchflussmesser-Prüfgerät, umfassend:

einen Einlass (122), der dafür konfiguriert ist, direkt mit einer Rohrleitung gekoppelt zu werden, die Tieftemperaturfluide befördert;

einen Auslass (124), der dafür konfiguriert ist, direkt mit der Rohrleitung gekoppelt zu werden, welche die Tieftemperaturfluide befördert;

ein Strömungsrohr (104, 204, 304), das zwischen den Einlass (122) und den Auslass (124) gekoppelt ist;

einen Verdränger (202, 302), der in einem Strömungskanal (224, 324) des Strömungsrohrs (104, 204, 304) beweglich ist und ein kohlenstofffreies magnetisches Bauteil umfasst;

worin das Strömungsrohr (104, 204, 304) und der Verdränger dafür konfiguriert sind, die Tieftemperaturfluide aufzunehmen; und

eine magnetische Sondenspule (232) und/oder ein Paar von Sendeempfängern (328, 330), die mit dem Strömungsrohr (104, 204, 304) gekoppelt sind und mit dem Verdränger kommunizieren,

worin der Strömungskanal (224, 324) eine Innenfläche (226, 326) mit einer Mikropolierung einschließt und worin das Prüfgerät zur Verwendung mit Tieftemperaturfluiden mit einer Temperatur von weniger als etwa -45,6 °C (-50 °F) eingerichtet ist.


 
2. Prüfgerät nach Anspruch 1, worin das kohlenstofffreie magnetische Bauteil mit dem Verdränger gekoppelt ist und mit der magnetischen Aufnahmespule (232) über den magnetischen Widerstand in Kommunikation steht.
 
3. Prüfgerät nach Anspruch 2, worin der Verdränger ein Kolben (202, 302) ist und das kohlenstofffreie magnetische Bauteil ein um den Kolben (202, 302) gewickelter Zielring (210) ist.
 
4. Prüfgerät nach Anspruch 1, worin das kohlenstofffreie magnetische Bauteil mit dem Verdränger gekoppelt ist und mit der magnetischen Aufnahmespule (232) in Kommunikation steht.
 
5. Prüfgerät nach Anspruch 4, worin das kohlenstofffreie magnetische Bauteil mindestens eines von Mu-Metall (µ-Metall), HYMU-Metall und HYMU-80-Metall umfasst.
 
6. Prüfgerät nach Anspruch 4, worin das kohlenstofffreie magnetische Bauteil eine Kombination aus Nickel, Eisen, Kupfer und/oder Molybdän umfasst.
 
7. Prüfgerät nach Anspruch 1, worin:

das Paar von Sendeempfängern (328, 330) ein Signal über den Strömungskanal (324) im Strömungsrohr (304) übermittelt; und

der Verdränger im Strömungskanal (324) beweglich ist, um das Signal zu unterbrechen.


 
8. Prüfgerät nach Anspruch 1, worin die Mikropolierung zur Schmierung eine mikroskopisch dünne Schicht der Tieftemperaturfluide zwischen der Innenfläche des Strömungskanals (226, 326) und dem Verdränger aufrechterhält; oder
worin die Mikropolierung im Bereich von 812,8 nm (32 Mikrozoll) bis 406,4 nm (16 Mikrozoll) liegt; oder
worin die Mikropolierung durch mindestens eines von Honen, Fräsen und Schleifen der Innenfläche erlangt wird.
 
9. Prüfgerät nach Anspruch 1, worin der Verdränger eine Leitfläche einschließt, die in einem Winkel relativ zur Strömungsrichtung der Tieftemperaturfluide angeordnet ist.
 
10. Prüfgerät nach Anspruch 9, worin der Verdränger ein Kolben (202, 302) ist, der eine Menge von inneren Leitflächen (216, 246) einschließt, die sich entlang einer Längsachse des Kolbens (202, 302) erstrecken und einen Winkel relativ zur Achse bilden; oder
worin die Leitfläche den Verdränger als Reaktion auf die Strömung der Tieftemperaturfluide dreht.
 
11. Prüfgerät nach Anspruch 1,
worin das Paar von Sendeempfängern (328, 330) ein Paar von Ultraschall-Sendeempfängern (328, 330) umfasst; oder
worin das Prüfgerät zur Verwendung mit Tieftemperaturfluiden mit einer Temperatur von weniger als etwa -140 °C (-220 °F) geeignet ist; oder
worin das Prüfgerät zur Verwendung mit Tieftemperaturfluiden eingerichtet ist, die mindestens eines von flüssigem Erdgas (LNG), flüssigem Stickstoff, flüssigem Butan, flüssigem Propan und verflüssigtem Petrolgas (LPG) aufweisen.
 
12. Prüfgerät nach Anspruch 1, worin der Verdränger ein Kolben (202, 302) ist, der beweglich ist, um das kohlenstofffreie magnetische Bauteil an der magnetischen Aufnahmespule (232) vorbei zu bewegen und mit der magnetischen Aufnahmespule (232) über den magnetischen Widerstand zu kommunizieren.
 
13. Prüfgerät nach Anspruch 12, worin die Mikropolierung eine Mikrodünnschicht aus Schmierfluid aufrechterhält.
 
14. Prüfgerät nach Anspruch 12, worin der Kolben (202, 302) einen Satz von den Kolben (202, 302) drehenden Leitflächen einschließt.
 
15. Prüfgerät nach Anspruch 12, ferner umfassend:

ein Paar von Ultraschall-Sendeempfängern (328, 330), die auf dem Strömungsrohr (104, 204, 304) angeordnet sind und über den Strömungskanal (224, 324) hinweg kommunizieren; und

worin die Bewegung des Kolbens (202, 302) die Kommunikation der Ultraschall-Sendeempfänger unterbricht.


 


Revendications

1. Dispositif de contrôle de débitmètre comprenant :

une entrée (122) qui est configurée de manière à ce qu'elle soit couplée directement à un pipeline qui transporte des fluides basses températures ;

une sortie (124) qui est configurée de manière à ce qu'elle soit couplée directement au pipeline qui transporte les fluides basses températures ;

un tuyau d'écoulement (104, 204, 304) qui est couplé entre l'entrée (122) et la sortie (124) ;

un moyen de déplacement (202, 302) qui peut être déplacé à l'intérieur d'un passage d'écoulement (224, 324) du tuyau d'écoulement (104, 204, 304) et qui comprend un élément magnétique exempt de carbone ;

dans lequel le tuyau d'écoulement (104, 204, 304) et le moyen de déplacement sont configurés de manière à ce qu'ils reçoivent les fluides basses températures ; et

une bobine exploratrice magnétique (232) et/ou une paire d'émetteurs-récepteurs (328, 330) qui sont/est couplée(s) au tuyau d'écoulement (104, 204, 304) et qui communique(nt) avec le moyen de déplacement ;

dans lequel le passage d'écoulement (224, 324) inclut une surface interne (226, 326) qui présente une microfinition et dans lequel le dispositif de contrôle est adapté de sorte qu'il soit utilisé avec des fluides basses températures qui présentent une température qui est inférieure à environ -45,6 °C (-50° F).


 
2. Dispositif de contrôle selon la revendication 1, dans lequel l'élément magnétique exempt de carbone est couplé au moyen de déplacement et est en communication avec la bobine exploratrice magnétique (232) via la réluctance magnétique.
 
3. Dispositif de contrôle selon la revendication 2, dans lequel le moyen de déplacement est un piston (202, 302) et l'élément magnétique exempt de carbone est un anneau cible (210) qui est enroulé autour du piston (202, 302).
 
4. Dispositif de contrôle selon la revendication 1, dans lequel l'élément magnétique exempt de carbone est couplé au moyen de déplacement et est en communication avec la bobine exploratrice magnétique (232).
 
5. Dispositif de contrôle selon la revendication 4, dans lequel l'élément magnétique exempt de carbone comprend au moins un métal pris parmi un métal de mu (µ) élevé, un métal HYMU et un métal HYMU 80.
 
6. Dispositif de contrôle selon la revendication 4, dans lequel l'élément magnétique exempt de carbone comprend une combinaison de nickel, de fer, de cuivre et/ou de molybdène.
 
7. Dispositif de contrôle selon la revendication 1, dans lequel :

la paire d'émetteurs-récepteurs (328, 330) communique un signal au travers du passage d'écoulement (324) à l'intérieur du tuyau d'écoulement (304) ; et

le moyen de déplacement peut être déplacé à l'intérieur du passage d'écoulement (324) de manière à ce qu'il interrompe le signal.


 
8. Dispositif de contrôle selon la revendication 1, dans lequel la microfinition maintient un film microscopique des fluides basses températures entre la surface interne de passage d'écoulement (226, 326) et le moyen de déplacement dans un but de lubrification ; ou
dans lequel la micro finition s'inscrit dans la plage de 812,8 nm (32 micro-pouces) à 406,4 nm (16 micro-pouces) ; ou
dans lequel la microfinition est obtenue au moyen d'au moins un processus pris parmi le rodage, le meulage et le polissage de la surface interne.
 
9. Dispositif de contrôle selon la revendication 1, dans lequel le moyen de déplacement inclut une vanne qui est disposée selon un certain angle par rapport à la direction d'écoulement des fluides basses températures.
 
10. Dispositif de contrôle selon la revendication 9, dans lequel le moyen de déplacement est un piston (202, 302) qui inclut un jeu de vannes internes (216, 246) qui s'étendent suivant un axe longitudinal du piston (202, 302) et qui définissent un angle par rapport à l'axe ; ou
dans lequel la vanne entraîne en rotation le moyen de déplacement en réponse à l'écoulement des fluides basses températures.
 
11. Dispositif de contrôle selon la revendication 1,
dans lequel la paire d'émetteurs-récepteurs (328, 330) comprend une paire d'émetteurs-récepteurs à ultrasons (328, 330) ; ou
dans lequel le dispositif de contrôle est adapté pour une utilisation avec des fluides basses températures qui présentent une température qui est inférieure à environ -140 °C (-220 °F) ; ou
dans lequel le dispositif de contrôle est adapté pour une utilisation avec des fluides basses températures qui comportent au moins un fluide pris parmi le gaz naturel liquide (LNG), l'azote liquide, le butane liquide, le propane liquide et le gaz de pétrole liquéfié (LPG).
 
12. Dispositif de contrôle selon la revendication 1, dans lequel le moyen de déplacement est un piston (202, 302) qui peut être déplacé de manière à ce qu'il déplace l'élément magnétique exempt de carbone au-delà de la bobine exploratrice magnétique (232) et de manière à ce qu'il assure une communication avec la bobine exploratrice magnétique (232) via la réluctance magnétique.
 
13. Dispositif de contrôle selon la revendication 12, dans lequel la microfinition maintient un microfilm de fluide de lubrification.
 
14. Dispositif de contrôle selon la revendication 12, dans lequel le piston (202, 302) inclut un jeu de vannes d'entraînement en rotation du piston (202, 302).
 
15. Dispositif de contrôle selon la revendication 12, comprenant en outre :

une paire d'émetteurs-récepteurs à ultrasons (328, 330) qui sont disposés sur le tuyau d'écoulement (104, 204, 304) et qui communiquent au travers du passage d'écoulement (224, 324) ; et

dans lequel le déplacement du piston (202, 302) interrompt la communication des émetteur-récepteur à ultrasons.


 




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Cited references

REFERENCES CITED IN THE DESCRIPTION



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Patent documents cited in the description