(19)
(11)EP 3 204 734 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
09.12.2020 Bulletin 2020/50

(21)Application number: 15781838.6

(22)Date of filing:  05.10.2015
(51)International Patent Classification (IPC): 
G01F 1/42(2006.01)
(86)International application number:
PCT/US2015/053932
(87)International publication number:
WO 2016/057366 (14.04.2016 Gazette  2016/15)

(54)

INTEGRATED ORIFICE PLATE ASSEMBLY

INTEGRIERTE LOCHPLATTENANORDNUNG

ENSEMBLE PLAQUE À ORIFICE INTÉGRÉ


(84)Designated Contracting States:
AL 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 RS SE SI SK SM TR

(30)Priority: 08.10.2014 US 201462061517 P
25.09.2015 US 201514865065

(43)Date of publication of application:
16.08.2017 Bulletin 2017/33

(73)Proprietor: Dieterich Standard, Inc.
Boulder, CO 80301 (US)

(72)Inventor:
  • HERING, Michael
    Louisville, CO 80027 (US)

(74)Representative: Isarpatent 
Patent- und Rechtsanwälte Behnisch Barth Charles Hassa Peckmann & Partner mbB Friedrichstrasse 31
80801 München
80801 München (DE)


(56)References cited: : 
WO-A1-01/20267
GB-A- 1 314 766
US-A- 1 480 661
US-A1- 2014 260 670
GB-A- 298 682
JP-U- H 075 022
US-A1- 2008 307 896
  
      
    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] The present invention relates to measurement of flow of process fluid. More specifically, the invention relates to measurement of a flow of process fluid by measuring a differential pressure generated across an orifice plate.

    [0002] Various techniques are known for measuring flow of process fluid. One technique involves the insertion of a restrictive element in a flow of process fluid. This element creates a differential pressure which can be measured and related to the flow rate.

    [0003] Orifice plates are one example of a restrictive element which can be placed in a flow of process fluid. An orifice plate assembly may include a number of components and fluidically couples to a process variable transmitter which is configured to measure a differential pressure. Some applications, such as nuclear safety and severe service related applications, are typically subject to the potential of severe vibration (seismic criteria), high temperature, high pressure, or all three. Such an environment may cause damage or failure to some prior art orifice plate assemblies and pressure measurement components. Documents JPH075022U, US2008/307896, WO 01/20267 A1 and GB 298 682 A disclose various orifice plate ; assemblies, wherein each orifice plate assembly comprises a single piece body, which includes a circumferential support ring having a first face configured to be sealingly coupled to a first flange of a first process pipe and a second face configured to be sealingly coupled to a second flange of a second process pipe, a flow plate region positioned between the first and second process pipes having first and second sides and concentric with the circumferential support ring, at least one flow orifice in the flow plate region configured to provide a restricted fluid path between the first and second process pipes. A first pressure tap is configured to fluidically couple the process variable transmitter to the process fluid proximate the first side of the flow plate region, and a second pressure tap is configured to fluidically couple the process variable transmitter to the process fluid proximate the second side of the flow plate region.

    SUMMARY



    [0004] A single piece orifice plate assembly includes an orifice plate configured to be positioned in a flow of process fluid. An integral circumferential support ring is provided. An upstream pressure tap extends through the circumferential support ring, and a downstream pressure tap which through the circumferential support ring.

    [0005] An orifice plate assembly for use with a process variable transmitter for measuring flow of a process fluid includes a single piece body having a circumferential support ring. A first face of the circumferential support ring is configured to be sealingly coupled to a first flange of a first process pipe. A second face of the circumferential support ring is configured to be sealingly coupled to a second flange of a second process pipe. The single piece body further has a flow plate region being positioned between the first and second pipes and having first and second sides. The flow plate region is concentric with the circumferential support ring. At least one flow orifice in the flow plate region provides a restricted fluid path between the first and second process pipes. The single piece body further has a first pressure tap extending through the circumferential support ring and being coupled to a first bore hole, which extends to the first side of the flow plate region, wherein the first pressure tap and the first bore hole are configured to fluidically couple to the process variable transmitter to the process fluid proximate the first side of the flow plate region. The single piece body further has a second pressure tap extending through the circumferential support ring and being coupled to a second bore hole, which extends to the second side of the flow plate region, wherein the second pressure tap and the second bore hole are configured to fluidically couple the process variable transmitter to the process fluid proximate the second side of the flow plate region. The first pressure tap and the second pressure tap are radially offset from one another.

    [0006] This Summary and the Abstract are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. The Summary and the Abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0007] 

    FIG. 1 is a front plan partial cutaway view of an integrated orifice plate assembly in accordance with one example embodiment.

    FIG. 2 is a side cross-sectional view of the integrated orifice plate assembly of FIG. 1.

    FIG. 3 is a perspective view of the integrated orifice plate assembly of FIG. 1.

    FIG. 4 is an exploded view of a pressure transmitter coupled to the orifice plate assembly illustrated in FIGS. 1-3.


    DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS



    [0008] An integrated/single piece orifice plate (wafer) assembly is provided which is formed as a single-piece wafer without any welds or appendages, and provides for easy centering in the pipe. The assembly does not contain any integrated instrument valves, allowing a user to provide their own, plant-specific instrument valves. The design allows a compact orifice plate configuration to be used with flanges of various ratings and can be offered in alternative materials.

    [0009] In one example aspect, a machined severe service compact orifice meter is designed to be inserted between pipes having two industry standard flanges. The wafer with integrated orifice plate is machined from a single piece or bar and matches the outer diameter (OD) of the mating flanges and contains bolt holes to allow bolting to be captured (and protected) by the wafer. Integrated threaded or socketweld taps employ a corner tap design and are spaced 90-degrees apart to reduce the thickness of the wafer and allow proper orientation of the taps depending on fluid service. The entire assembly does not require any moving parts, gaskets, bolts, studs, or nuts other than the gaskets, bolts and nuts used to mount the assembly to pipe flange. The compact wafer design with integral remote connections allow the device to be used at high pressures/temperatures, and/or in high vibration environments.

    [0010] As the device is made from a single piece of material, it can be made from any suitable available material that can be machined, 3D printed in plastic or metal or otherwise manufactured.

    [0011] FIGS. 1, 2 and 3 show a front plan, a side cross-sectional and a perspective view of an integrated compact conditioning orifice plate assembly 100 in accordance with one example configuration.

    [0012] Orifice plate assembly 100 is a single piece body which includes circumferential support ring 102 having opposed first and second faces which supports an orifice plate region 104. Flow plate 104 also has opposed first and second sides and is arranged concentric with circumferential support ring 102. Elements 102 and 104 are formed integrally and, are not welded or otherwise bonded together as separate components. Orifice plate 104 is illustrated as a conditioning orifice plate which includes four radially spaced openings (flow orifices) 104A which are configured to reduce disturbances in the flow of process fluid as the process fluid passes through the openings 104A. Circumferential support ring 102 includes a plurality of openings 106 formed therein which are configured to receive mounting bolts (120 in FIG. 4) therethrough. Opposed pipe flanges (122 in FIG. 4) are sealably mounted to either side of the circumferential support ring 102. Pressure taps 108 and 110 extend through the circumferential support ring 102 and into the flow of process fluid.

    [0013] Pressure taps 108 and 110 are radially offset to reduce the thickness of the circumferential support ring 102. Taps 108, 110 couple to bore holes 109, 111 which extend to opposed sides of the flow plate 104. In one specific configuration, taps 108 and 110 are arranged at 90° relative to one another. A corner tap or flange tap configuration can be used. Conduits (shown in FIG. 4) are coupled to pressure taps 108 and 110 and are used to fluidically couple a pressure transmitter (not shown) to the upstream and downstream pressures. This allows the pressure transmitter to measure a differential pressure which is related to the flow of process fluid.

    [0014] FIG. 4 is an exploded perspective view of a flow measuring system 118 according to one embodiment including a pressure transmitter 124. Orifice plate assembly 100 is mounted between flanges 122 of process piping 126. The flanges 122 include bolt holes 128 which align with holes 106 of orifice plate assembly 100 and are configured to receive bolts 120 therethrough. Bolts 120 are secured with nuts 130.

    [0015] As illustrated in FIG. 4, impulse piping 134 and 136 are received in taps 108 and 110, respectively. These connections can use, for example, threading or other attachment techniques such as welds. Impulse piping 134 and 136 couple to a manifold 140. Manifold 140 is illustrated as including a number of valves and is used to fluidically couple a differential pressure from taps 108, 110 to pressure inputs (not shown) of pressure transmitter 124. A differential pressure sensor 150 is carried within the pressure transmitter 124 and is responsive to the applied differential pressure. The differential pressure sensor 150 may be an individual differential pressure sensor or may be configured as two separate static pressure transmitters designed to sense the upstream and downstream pressures on either side of the orifice plate assembly 100. Transmitter circuitry 152 of transmitter 124 is electrically connected to the pressure sensor 150 and is configured to provide an output related to the differential pressure. This differential pressure is indicative of the flow of process fluid through the orifice plate assembly 100.

    [0016] As illustrated in FIG. 4, orifice plate 104 is generally aligned with the openings 116 of process piping 126. The opposed sides of the circumferential support ring 102 seal against faces of flanges 122 through a force applied by bolts 120. In this configuration, the flow of process fluid from the process piping 126 is forced through the openings 104A of orifice plate 104. The transmitter circuitry can provide an output on a two-wire process control loop such as is known in the art. For example, a two-wire process control loop can be used to carry information as well as provide power to the device. The communication can be in an analog format, such as a 4-20 mA current level, or may alternatively or additionally include a digital signal. Wireless communication techniques may also be employed for example, in accordance with the WirelessHART® communication protocol in accordance with IEC 62591 or using other techniques. Transmitter 124 is illustrated as including an optional antenna 160 for such wireless communication.

    [0017] The configuration discussed herein provides a single piece design which is well suited for application in severe environments such as those that experience vibration, high temperature and/or high pressure. One specific application is for nuclear safety related implementations. The single piece design mitigates expansion and contraction issues which may be problematic in high temperature applications. Different size integral orifice plates can be provided for use with differing line sizes. Although a conditioning orifice plate including four openings is illustrated, any orifice plate configuration may be implemented. The orifice plate assembly may be fabricated using molding techniques or machined from a single piece of material such as metal or plastic. One example material is stainless steel. In another configuration, the orifice plate assembly is fabricated using an additive technique such as, for example, using 3D printing techniques.

    [0018] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the invention as defined by the appended claims. The single piece of orifice plate assembly can be fabricated of any appropriate material including plastics or metals. One typical metal which may be used is stainless steel. The pressure taps can be in accordance with standardized connections such as NPT (National Pipe Thread) connections. The diameter of the circumferential support ring can be selected to match the diameter of the pipe flanges to allow easy alignment of the flow plate region with the orifices of the pipes. The arrangement facilitates remote mounting of the pressure transmitter with respect to the orifice plate assembly and connected to the pressure taps using impulse piping. Although only two pressure taps are illustrated, any number of pressure taps may be employed. The thickness of the orifice plate region may be the same as, thicker than, or thinner than, the thickness of the circumferential support ring. As used herein, the terms integrated and single piece refer to a configuration in which the orifice plate is formed from a single piece of material rather than by attaching individual piece together.


    Claims

    1. An orifice plate assembly (100) for use with a process variable transmitter (124) for measuring flow of a process fluid, the orifice plate assembly (100) comprising:
    a single piece body including:

    a circumferential support ring (102) having a first face configured to be sealingly coupled to a first flange (122) of a first process pipe (126) and a second face configured to be sealingly coupled to a second flange (122) of a second process pipe (126);

    a flow plate region (104) positioned between the first and second process pipes (126) having first and second sides and concentric with the circumferential support ring (102);

    at least one flow orifice (104A) in the flow plate region (104) configured to provide a restricted fluid path between the first and second process pipes (126);

    a first pressure tap (108) extending through the circumferential support ring (102) and being coupled to a first bore hole (109), which extends to the first side of the flow plate region (104), wherein the first pressure tap (108) and the first bore hole (109) are configured to fluidically couple the process variable transmitter (124) to the process fluid proximate the first side of the flow plate region (104); and

    a second pressure tap (110) extending through the circumferential support ring (102) and being coupled to a second bore hole (111), which extends to the second side of the flow plate region (104), wherein the second pressure tap (110) and the second bore hole (111) are configured to fluidically couple the process variable transmitter (124) to the process fluid proximate the second side of the flow plate region (104), wherein the first pressure tap (108) and the second pressure tap (110) are radially offset from one another.


     
    2. The orifice plate assembly of claim 1 including first and second impulse piping coupled to respective first pressure tap (108) and second pressure tap (110).
     
    3. The orifice plate assembly of claim 2 wherein the first and second impulse piping couple to inlets of the process variable transmitter (124), in particular including a manifold to couple the impulse piping to the process variable transmitter (124).
     
    4. The orifice plate assembly of claim 1, wherein the radial offset of the first pressure tap (108) and the second pressure tap (110) in particular comprises 90°.
     
    5. The orifice plate assembly of claim 1 wherein the orifice plate comprises a conditioning orifice plate, wherein the conditioning orifice plate in particular comprises a flat circular section having a plurality of openings formed therethrough.
     
    6. The orifice plate assembly of claim 1 wherein the circumferential support ring (102) includes a plurality of mounting holes configured to receive bolts therethrough to secure the circumferential support ring (102) to the first and second flanges (122) of the respective first and second process pipes (126).
     
    7. The orifice plate assembly of claim 1 including a pressure transmitter fluidically coupled to the first pressure tap (108) and second pressure tap (110) and configured to measure a differential pressure therebetween.
     
    8. The orifice plate assembly of claim 1 wherein the circumferential support ring (102) and the flow plate region (104) are machined as a single piece.
     
    9. The orifice plate assembly of claim 1 wherein the circumferential support ring (102) and the flow plate region (104) are fabricated using 3D printing techniques.
     
    10. The orifice plate assembly of claim 1 wherein the circumferential support ring (102) and integral orifice plate are formed of a metal.
     
    11. The orifice plate assembly of claim 1 wherein the circumferential support ring (102) and integral orifice plate are formed of a plastic.
     
    12. The orifice plate assembly of claim 1 wherein the orifice plate region includes four flow orifices.
     
    13. The orifice plate assembly of claim 1 wherein the orifice plate region has a thickness which is less than a thickness of the circumferential support ring (102).
     
    14. The orifice plate assembly of claim 1 wherein the orifice plate region has a thickness which is the same as a thickness of the circumferential support ring (102).
     


    Ansprüche

    1. Öffnungsplattenanordnung (100) zur Verwendung mit einem Prozessvariablensender (124) zum Messen des Durchflusses eines Prozessfluids, wobei die Öffnungsplattenanordnung (100) umfasst:
    einen einstückigen Körper, umfassend:

    einen umfänglichen Stützring (102) mit einer ersten Fläche, die dafür eingerichtet ist, abdichtend mit einem ersten Flansch (122) eines ersten Prozessrohres (126) gekoppelt zu werden, und einer zweiten Fläche, die dafür eingerichtet ist, abdichtend mit einem zweiten Flansch (122) eines zweiten Prozessrohres (126) gekoppelt zu werden;

    eine Durchflussplattenregion (104), die zwischen dem ersten und dem zweiten Prozessrohr (126) angeordnet ist, eine erste und eine zweite Seite aufweist und mit dem umfänglichen Stützring (102) konzentrisch verläuft;

    mindestens eine Durchflussöffnung (104A) in der Durchflussplattenregion (104), die dafür eingerichtet ist, einen verengten Fluidpfad zwischen dem ersten und dem zweiten Prozessrohr (126) zu bilden;

    einen ersten Druckabgriff (108), der sich durch den umfänglichen Stützring (102) erstreckt und mit einem ersten Bohrloch (109) gekoppelt ist, das sich zu der ersten Seite der Durchflussplattenregion (104) erstreckt, wobei der erste Druckabgriff (108) und das erste Bohrloch (109) dafür eingerichtet sind, den Prozessvariablensender (124) mit dem Prozessfluid in der Nähe der ersten Seite der Durchflussplattenregion (104) in Strömungsverbindung zu setzen; und

    einen zweiten Druckabgriff (110), der sich durch den umfänglichen Stützring (102) erstreckt und mit einem zweiten Bohrloch (111) gekoppelt ist, das sich zu der zweiten Seite der Durchflussplattenregion (104) erstreckt, wobei der zweite Druckabgriff (110) und das zweite Bohrloch (111) dafür eingerichtet sind, den Prozessvariablensender (124) mit dem Prozessfluid in der Nähe der zweiten Seite der Durchflussplattenregion (104) in Strömungsverbindung zu setzen, wobei der erste Druckabgriff (108) und der zweite Druckabgriff (110) radial voneinander versetzt sind.


     
    2. Öffnungsplattenanordnung nach Anspruch 1, die eine erste und eine zweite Impulsrohrleitung umfasst, die mit dem ersten Druckabgriff (108) bzw. dem zweiten Druckabgriff (110) gekoppelt ist.
     
    3. Öffnungsplattenanordnung nach Anspruch 2, wobei die erste und die zweite Impulsrohrleitung mit Einlässen des Prozessvariablensenders (124) gekoppelt sind und insbesondere einen Verteiler umfassen, um die Impulsrohrleitungen mit dem Prozessvariablensender (124) zu verbinden.
     
    4. Öffnungsplattenanordnung nach Anspruch 1, wobei insbesondere der radiale Versatz des ersten Druckabgriffs (108) und des zweiten Druckabgriffs (110) 90° beträgt.
     
    5. Öffnungsplattenanordnung nach Anspruch 1, wobei die Öffnungsplatte eine Konditionierungsöffnungsplatte umfasst, wobei die Konditionierungsöffnungsplatte insbesondere einen flachen kreisförmigen Querschnitt umfasst, durch den hindurch mehrere Öffnungen ausgebildet sind.
     
    6. Öffnungsplattenanordnung nach Anspruch 1, wobei der umfängliche Stützring (102) mehrere Montagelöcher umfasst, die dafür eingerichtet sind, durch sie hindurchgeführte Schrauben aufzunehmen, um den umfänglichen Stützring (102) an dem ersten und dem zweiten Flansch (122) des ersten bzw. des zweiten Prozessrohres (126) zu befestigen.
     
    7. Öffnungsplattenanordnung nach Anspruch 1, die einen Drucksender umfasst, der mit dem ersten Druckabgriff (108) und dem zweiten Druckabgriff (110) in Strömungsverbindung steht und dafür eingerichtet ist, eine Differenzdruck dazwischen zu messen.
     
    8. Öffnungsplattenanordnung nach Anspruch 1, wobei der umfängliche Stützring (102) und die Durchflussplattenregion (104) einstückig miteinander gefertigt sind.
     
    9. Öffnungsplattenanordnung nach Anspruch 1, wobei der umfängliche Stützring (102) und die Fließplattenregion (104) unter Verwendung von 3D-Drucktechniken gefertigt sind.
     
    10. Öffnungsplattenanordnung nach Anspruch 1, wobei der umfängliche Stützring (102) und die integrale Öffnungsplatte aus einem Metall gebildet sind.
     
    11. Öffnungsplattenanordnung nach Anspruch 1, wobei der umfängliche Stützring (102) und die integrale Öffnungsplatte aus einem Kunststoff gebildet sind.
     
    12. Öffnungsplattenanordnung nach Anspruch 1, wobei die Öffnungsplattenregion vier Durchflussöffnungen umfasst.
     
    13. Öffnungsplattenanordnung nach Anspruch 1, wobei die Öffnungsplattenregion eine Dicke aufweist, die geringer ist als eine Dicke des umfänglichen Stützrings (102).
     
    14. Öffnungsplattenanordnung nach Anspruch 1, wobei die Öffnungsplattenregion eine Dicke aufweist, welche die gleiche ist wie die Dicke des umfänglichen Stützrings (102).
     


    Revendications

    1. Ensemble de plaque à orifices (100) pour une utilisation avec un transmetteur de condition opératoire (124) destiné à mesurer un débit d'un fluide de traitement, l'ensemble de plaque à orifices (100) comprenant :
    un corps d'une seule pièce comportant :

    un anneau de support circonférentiel (102) ayant une première face configurée pour être couplée de manière étanche à une première bride (122) d'un premier conduit de traitement (126) et une seconde face configurée pour être couplée de manière étanche à une seconde bride (122) d'un second conduit de traitement (126) ;

    une région de plaque de débit (104) positionnée entre les premier et second conduits de traitement (126) ayant des premier et second côtés et étant concentrique avec l'anneau de support circonférentiel (102) ;

    au moins un orifice de débit (104A) dans la région de plaque de débit (104) configuré pour former un trajet de fluide restreint entre les premier et second conduits de traitement (126) ;

    une première prise de pression (108) s'étendant à travers l'anneau de support circonférentiel (102) et étant couplée à un premier trou d'alésage (109), qui s'étend jusqu'au premier côté de la région de plaque de débit (104), dans lequel la première prise de pression (108) et le premier trou d'alésage (109) sont configurés pour coupler fluidiquement le transmetteur de condition opératoire (124) au fluide de traitement à proximité du premier côté de la région de plaque de débit (104), et

    une seconde prise de pression (110) s'étendant à travers l'anneau de support circonférentiel (102) et étant couplée à un second trou d'alésage (111), qui s'étend jusqu'au second côté de la région de plaque de débit (104), dans lequel la seconde prise de pression (110) et le second trou d'alésage (111) sont configurés pour coupler fluidiquement le transmetteur de condition opératoire (124) au fluide de traitement à proximité du second côté de la région de plaque de débit (104),

    dans lequel la première prise de pression (108) et la seconde prise de pression (110) sont décalées radialement l'une de l'autre.


     
    2. Ensemble de plaque à orifices selon la revendication 1, comportant des première et seconde conduites d'impulsion couplées aux première prise de pression (108) et seconde prise de pression (110) respectives.
     
    3. Ensemble de plaque à orifices selon la revendication 2, dans lequel les première et seconde conduites d'impulsion se couplent à des entrées du transmetteur de condition opératoire (124), comportant en particulier un collecteur pour coupler la conduite d'impulsion au transmetteur de condition opératoire (124).
     
    4. Ensemble de plaque à orifices selon la revendication 1, dans lequel le décalage radial de la première prise de pression (108) et de la seconde prise de pression (110) en particulier comprend 90°.
     
    5. Ensemble de plaque à orifices selon la revendication 1, dans lequel la plaque à orifices comprend une plaque à orifices de conditionnement, dans lequel la plaque à orifices de conditionnement en particulier comprend une section circulaire plate ayant une pluralité d'ouvertures formées à travers elle.
     
    6. Ensemble de plaque à orifices selon la revendication 1, dans lequel l'anneau de support circonférentiel (102) comporte une pluralité de trous de montage configurés pour recevoir des boulons à travers eux afin d'arrimer l'anneau de support circonférentiel (102) aux première et seconde brides (122) des premier et second conduits de traitement (126) respectifs.
     
    7. Ensemble de plaque à orifices selon la revendication 1, comportant un transmetteur de pression couplé fluidiquement à la première prise de pression (108) et à la seconde prise de pression (110) et configuré pour mesurer une pression différentielle entre elles.
     
    8. Ensemble de plaque à orifices selon la revendication 1, dans lequel l'anneau de support circonférentiel (102) et la région de plaque de débit (104) sont usinés d'une seule pièce.
     
    9. Ensemble de plaque à orifices selon la revendication 1, dans lequel l'anneau de support circonférentiel (102) et la région de plaque de débit (104) sont fabriqués à l'aide de techniques d'impression 3D.
     
    10. Ensemble de plaque à orifices selon la revendication 1, dans lequel l'anneau de support circonférentiel (102) et la plaque à orifices d'un seul tenant (104) sont formés d'un métal.
     
    11. Ensemble de plaque à orifices selon la revendication 1, dans lequel l'anneau de support circonférentiel (102) et la plaque à orifices d'un seul tenant (104) sont formés d'une matière plastique.
     
    12. Ensemble de plaque à orifices selon la revendication 1, dans lequel la région de plaque à orifices comporte quatre orifices de débit.
     
    13. Ensemble de plaque à orifices selon la revendication 1, dans lequel la région de plaque à orifices a une épaisseur qui est inférieure à une épaisseur de l'anneau de support circonférentiel (102).
     
    14. Ensemble de plaque à orifices selon la revendication 1, dans lequel la région de plaque à orifices a une épaisseur qui est la même qu'une épaisseur de l'anneau de support circonférentiel (102).
     




    Drawing

















    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description