WO2011073292A1

WO2011073292A1 - Shrouded fluid duct

Info

Publication number: WO2011073292A1
Application number: PCT/EP2010/069835
Authority: WO
Inventors: Herbert Heinzinger
Original assignee: Eaton Fluid Power Gmbh
Priority date: 2009-12-16
Filing date: 2010-12-15
Publication date: 2011-06-23
Also published as: GB2478513A; GB0921906D0; EP2513548A1

Abstract

The disclosed fluid duct for ducting a fluid between a fluid source and a fluid drain with high flow rates comprises a rigid inner part and a flexible outer part wherein the rigid inner part provides at least one degree of freedom and wherein the flexible outer part secures that the fluid can not penetrate to the outside but is flexible enough so that it does not hinder said at least one degree of freedom.

Description

Shrouded Fluid Duct

TECHNICAL FIELD

This invention relates to the field of mechanical conduits, connectors or ducts that are used to interconnect at least two hose or tube assemblies conducting a fluid with each other or to interconnect a hose or tube assembly with a filler opening or plug of a building, vehicle, like a fuel filler neck of an automobile or aircraft, and in particular to connectors or ducts that can be used to duct highly pressurized fluids with high flow rates.

BACKGROUND

Fluid connectors or ducts as mentioned above are known in the art and typically comprise a hose or tube which is terminated on both sides with flanges that allow the connector or duct to be connected on each side to a filler opening, plug, hose or tube assembly. Using these connectors or ducts, fuel ducting hoses or tubes of a fluid reservoir, like a fueling vehicle in the automotive or aerospace field, can be connected to a fluid consumer, e.g. an according automobile or aircraft. In particular in the aerospace field there are known connectors and ducts to fuel an aircraft which, in view of the large amount of fuel being filled with, have to bear up or withstand relatively high flow rates and according fluid pressures.

In such high fluid flow or pressure applications it is highly desirable to provide a connector or duct that can be connected easily to both the fueling target, or a respective fluid hose or tube thereof, and a filler neck of the aircraft and, at the same time, comprises the mechanical rigidity or stability required for the high flow rates. SUMMARY

The proposed fluid duct, according to a first aspect of the invention, is double- walled and comprises a rigid inner part or wall and a flexible outer part (wall or shroud). The rigid inner part provides the required mechanical stability in particular for high flow rates of a conducted fluid but, at the same time, provides at least one degree of freedom, either for a change of its length within a certain range and/or for a rotational movement of one end of the fluid duct in relation to the other end. The flexible outer part, on the one hand, secures that the fluid can not penetrate to the outside, i.e. the environment, which may happen in view of the necessary mechanical connections of the inner part that allow for the mentioned linear and/or rotational degrees of freedom. On the other hand, the outer part is flexible enough so that it does not affect, i.e. hinder, or even prevent, such movements. The inner part thus allows to conduct high pressurized fluid wherein the outer part mainly serves as a protective shield in order to prevent fluid that is leaked from the inner part to reach the

environment.

In a second aspect, the fluid duct comprises connectors at both ends which are used to connect the fluid duct with a preferably highly pressurized fluid reservoir on the one side and a consumer or tank or vessel on the other side. The mentioned degrees of freedom (variable length and/or orientation) reduce the necessary efforts for an operator because they provide some "tolerance" for connecting the fluid duct on both sides using these connectors. Possible connectors are flanges or screw taps or any other type of connectors that provide a stable connection even under high pressures.

In a third aspect, the inner part is made of a metal alloy or any other rigid material like ceramics or plastics that can bear up high fluid pressures but also provides a structure that allows for the mentioned degrees of freedom. In a fourth aspect, the outer part is preferably made of convoluted nitrile rubber but can be made of other flexible materials or classes of materials like plastic, metal or glass fiber, preferably bellows made of such materials. According to a further aspect, the fluid duct can be manufactured either as a one-part or multi-part device. In case of a multi-part device, the fluid duct comprises at least one fixing, fastening or mounting means by which the parts are fixedly mounted with each other. Preferably, clamps can be used for this purpose but the present invention is not limited to the particular technology being used because the general concept of the invention does not rely upon how to fix the parts.

According to still another aspect, at least one end of the inner part of the fluid duct having the mentioned rotational degree of freedom comprises a bent or curved shaped of inner part. Of course, it is well-understood that this curved structure can also be realized with the flexible outer part of the fluid duct, but not necessarily.

In a further aspect, the flexible outer part of the fluid duct can comprise at least one flex bellow or bellow-type seal. Such parts provide the required flexibility but, at the same time, the necessary leak tightness.

In another aspect, the inner part can comprise a perforation which allows for a controlled leakage or exchange of fluid between the inner part and the circular or ring- shaped space between the inner part and the outer part. The proposed fluid connector or duct concept advantageously provides for a light weight, e.g. about 10 - 15 kg, and double wall fuel duct solution which can be easily handled and manufactured. Such a connector of a size typically ranging from about 0.2 m to 1-2 m can be used preferably as a fuel duct that provides high flow rates of the fuel in order to fuel or refuel a vehicle like an aircraft in a relatively short time.

The proposed fluid connector allows to be manufactured using materials which result in an electrical resistance from flange to flange not exceeding a certain maximum value, preferably 0,1 Ohm and more preferably below 0,05 Ohm so that electrical discharges due to static electricity are prevented.

The used materials enable operating temperatures in the range of about -50°C and +50°C so that the fluid connector can be used in a broad temperature range depending on the location of the vehicle to be fueled.

Beyond that, the materials that can be used in accordance with the proposed design allow for working pressures for the inner tube (pipe) of about or even beyond 100 psi and for the outer tube (shroud) of about or even beyond 50 psi which enable to duct the mentioned high flow rates of the fluid.

It is emphasized that the inventive concept can also be used in all kinds of fluid connectors or ducts and the term fluid connector or duct being used throughout this document insofar is understood not to be limited to a certain application field, like the mentioned fueling of vehicles, and can be applied in other areas like high-pressure water conduits or chemical or process engineering where highly pressurized fluids or liquids are conducted or transmitted using pipes, tubes or hoses. In addition, the term "fluid", as understood herein, embraces liquids or other fluids or classes/types of fluids where the present invention can be used. Preferable application scenarios are fueling or refueling of vehicles, fuel conveyance or fluid-based trimming in aircrafts, or fueling/refueling of chemical fluids with chemical reactors or tanks, e.g. those used in chemical/process engineering.

Further respective aspects and features of the invention are defined in the appended claims, including but not limited to the following description. BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the invention will be apparent from the following detailed description of illustrative embodiments which is to be read in connection with the accompanying drawings, in which:

FIG. 1 is a schematic lateral sectional view of a fluid connector according to the invention; FIG. 2 is a more detailed perspective view of an embodiment of the fluid connector illustrated in FIG. 1;

FIG. 3 is a lateral sectional view of the fluid connector shown in FIG. 2; and FIG. 4 is an enlarged sectional view of a chamber being part of the annular space between the inner part and outer part of a fluid connector shown in FIG. 3.

DETAILED DESCRIPTION Exemplary embodiments of the invention now will be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein;

rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular exemplary

embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

Referring to FIG. 1, the general concept of a fluid connector or duct according to the present invention is illustrated by way of a schematic sectional side view. The connector comprises a rigid inner part 100, in the present embodiment a metal tube made e.g. of stainless steel, metal alloy, ceramics or rigid plastics, and a flexible outer part 105, in the present embodiment a flexible hose made of convoluted nitrile rubber.

The inner part 100, in the present embodiment, consists of four sections 110 -125, namely two straight tube sections 110, 115 arranged in the middle of the fluid connector and two bent or curve-shaped tube sections 120, 125 arranged at each end of the straight tube sections 110, 115.

The straight tube sections 110, 115 can be pushed together or pulled apart from each other by a telescope connection thus providing a linear or longitudinal degree of freedom along the length of the fluid connector (i.e. variable length). This degree of freedom within a predetermined range of length illustrated by arrow 130, in the present embodiment, is provided by an overlapping area of the two straight tube sections 110, 115 designated by circle 135 which shows part of the area where the two tubes 110, 115 mesh or interlock like a telescope.

The curve-shaped tube sections 120, 125 are connected with their corresponding straight tube sections 110, 115 by means of two rotatable connectors which are designated by circles 140, 145. These connectors 140, 150 allow for a rotational movement of the two bent tube sections 120, 125 in relation to the two straight tube sections 110, 115, as illustrated by the two arrows 150, 155. A preferred embodiment of such a connector is described by way of the embodiment shown in FIGS 2 and 3 and comprises clamps to fasten a straight tube section with a bent tube section. This mechanical structure of the fluid connector secures that fluid can not penetrate to the outside but is flexible enough so that it does not affect said degrees of freedom.

The rotational degree of freedom of the bent tube sections 120, 125, in combination with their bent shape, eases the use of the fluid connector in situations where the orientation of the fluid source and the fluid drain is tilt relative to each other and the underlying tilt angle can be compensated by rotating one bent tube section relative to the other bent tube section. In the present embodiment, all four inner tube sections 110 - 125 comprise holes or perforations 160 which, as already mentioned, allow for a controlled exchange of fluid between the inner part 100 and the annular space 165 arranged between the inner 100 and outer part 105 of the fluid connector. In the present embodiment, these perforations 160 are arranged in the longitudinal direction of the fluid connector but can also be arranged circumferentially at one or more of the tubes of the inner part, like in the embodiment shown in FIG. 3. However, it is well understood that these holes are provided only preferably and not necessarily provided at each inner tube section 110 - 125.

In the present embodiment, the flexible outer part 105 is made of convoluted nitrile rubber and comprises a number of flex bellow structures 170, or bellow-type seal structures respectively. These structures 170 provide the required flexibility but, at the same time, the necessary leak tightness of the entire fluid connector. It is noteworthy that instead of nitrile rubber there can be used any other plastic material or metals like aluminum or metal alloys and that instead of the shown flex bellow structures there can be used any other structure that provides the necessary flexibility or variability along the length of the fluid connector.

In the present embodiment, the fluid connector at both ends comprises flanges 175 which are welded to both the corresponding bent inner tube sections 120, 125 of the inner part 100 and the outer part 105, as designated by circles 180, 185. By these flanges 175 the fluid connector can easily be connected to the fluid source and the fluid drain. However, it is well understood that instead of flanges, depending on the application field, there can be used screw taps or the like instead.

As can be seen in FIG. 3, both bent tube sections 120, 125 are fixed to the straight tube sections 110, 115 and by screws 345, 430. Using the shown "ball-joint" connection design it is possible to move or rotate the bent tube sections 120, 125 in each direction within a range of about +/- 12 degrees. The ball-joint connection can be sealed with conventional or customized O-rings thus revealing a connection which is 100% leakage- free, at least within the mentioned range of movement/rotation.

It is noted that the shown fluid connector comprises one curve-shaped tube section ("elbows" 120 or 125) at each end. But the described longitudinal and rotational degrees of freedom of the inner part can also be achieved with only one connector so that the entire inner part of such a fluid connector is made of (only) two tubes. Such a combined connector can be implemented using the above described connector concept with two overlapping tubes (telescope structure) 135.

FIG. 2 shows a preferred embodiment of the double- walled fluid connector according to the invention. For similar or functional identical features the corresponding reference numerals/signs of FIG. 1 are used. As already illustrated in FIG. 1, the flexible outer part or wall (in the following called "shroud") and the inner part or wall are fixed with each other at both ends, in proximity to the two flanges 175 at both ends of the fluid connector, like in the first embodiment depicted in FIG. 1. In the present embodiment, the (outer) shroud 105 consists of two parts wherein each of these parts is connected to a flange as described beforehand. In the present

embodiment, this connection (fixed or mounted) is not a permanent weld joint but a removable or detachable connection using a first and a second band clamp 205, 225 on each side of the fluid connector. A third band clamp 200 is used to tightly connect the two parts of a two-part (outer) shroud 105 with each other and the inner tube 110.

It is emphasized that this kind of fixation of the two parts of the shroud does not affect or hinder a longitudinal movement of the telescope but moreover stabilizes the whole double- walled structure of the fluid connector.

Reference numerals 210, 215 and 220 depict a so-called "bonding cable" which functions as electrical ground in order to prevent electrical discharge due to static electricity. This cable 210, which is hidden in the view shown in FIG. 2, extends from the left to the right of the connector.

FIG. 3 depicts a more detailed sectional view of the fluid connector shown in FIG. 2.

In the present embodiment, the inner tube consists of four parts namely two elbow assemblies 120, 125 arranged at both ends of the fluid connector and two straight tube parts, a first inner tube 320 and a second inner tube 325, designate a "telescope" tube joint (movement illustrated by the arrow 130, like in FIG. 1). As shown in FIG. 2, the flanges 175 and the shrouds 105 are connected using band clamps 205, 225. In the present embodiment, the connection additionally includes a sealing 315, preferably a sealing strip material, being arranged between the outside of the respective flange 175 and the inside of the respective shroud 105. The telescope length, in the present example, can be varied by +/- 30 mm, but this length can vary, e.g. depending from the underlying application field of the fluid connector. Similar to FIG. 1, the embodiment according to FIGs 2 and 3 provides perforations 160 but, in contrast to FIG. 1, these perforations are only located at the first inner tube 320 of the telescope 320, 325.

In the present embodiment, the two tubes of the inner part are made of a TiAlV alloy. But there exist other metal or even composite materials that can be used, like steel CRES 304, stainless steel or Aluminum. Based on the mentioned TiAlV alloy, the maximum working pressure of the inner part (internal pipe) is more than 100 psi and more than 50 psi for the outer part (shroud). However, these pressure values may vary depending on the underlying materials being used. With a diameter of the inner part (internal pipe) of about 5 cm, fluid flow rates of up to 5000 1/s are possible.

In FIG. 3, the reference numerals 300 - 310 designate areas where the fluid connector is cut open in order to show internal components which are used to connect all the tube and shroud parts with each other but providing the mentioned longitudinal and rotational degrees of freedom.

The fluid connector comprises a housing 420 and a so-called "slip tube" 110 which together constitute a telescope which allows for an axial movement of about +/- 30 mm. The housing 420 and the slip tube 110 are fixed to each other by means of so-called "retainers" 390, 400 and wires 375, 395. To prevent leakage, in particular during movement of the slip tube 110 in relation to the housing 420, O-rings 385, 410 are arranged as sealing. In order to further stabilize the connection of these tubes and to prevent tilt of these tubes during movement, wear rings 370, 420 are provided.

As already mentioned, the preferred embodiment of the fluid connector, preferably in the slip tube 110, comprises holes or perforations 160 by which a so-called "pressure balance principle" can be realized.

As illustrated by the enlarged sectional view in FIG. 4 of the flex bellow structure 170 of the preferred embodiment of the fluid connector, the annular space 165 comprises a fluid chamber 500 which is arranged between the retainers 390, 400 and along the annular row of perforations 160. Under high fluid flows or pressures (e.g. more than 4000 1/min), the above described slip tube design has the drawback that both telescope tubes, i.e. the first inner tube 320 and the second inner tube 325, tend to move apart from each other thus elongating the telescope connection 320, 325. The underlying force F can be calculated by the product of pressure force P (see reference numeral 510) and surface area A of the mentioned chamber/space by equation F = P x A.

In order to antagonize or countervail these forces, by means of the perforations 160, the fluid can enter the fluid chamber 500 with high pressure. The resulting fluid pressure in the fluid chamber 500 is the same as the fluid pressure in the first inner tube 320. This resulting fluid pressure acts on the retainers 390, 400 in the reverse direction thus working against the mentioned elongation of the telescope 320, 325. As both pressures are the same, the two counteracting forces are balanced, or at least essentially balanced. While in the preceding description illustrative/specific embodiments of the invention have been described in detail, it is to be understood that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure, without departing from the scope and spirit of the invention as defined by the appended claims. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.

Modifications and alternative embodiments of this invention will be apparent to those skilled in the art in view of this description of the invention. Accordingly, this description teaches those skilled in the art the manner of carrying out the invention and is intended to be construed as illustrative only. The forms of the invention shown and described constitute the present embodiments. Persons skilled in the art may make various changes in the shape, size and arrangement of parts. For example, persons skilled in the art may substitute equivalent elements for the elements illustrated and described here. Moreover, persons skilled in the art after having the benefit of this description of the invention may use certain features of the invention independently of the use of other features, without departing from the scope of the invention.

Claims

1. Fluid duct for conducting a fluid between a fluid source and a fluid drain with high flow rates, comprising a rigid inner part and a flexible outer part wherein the rigid inner part provides at least one degree of freedom and wherein the flexible outer part secures that the fluid can not penetrate to the outside but is flexible enough so that it does not affect said at least one degree of freedom.

2. Fluid duct according to claim 1 comprising a connector at each end being used to connect the fluid duct with fluid source and the fluid drain.

3. Fluid duct according to claim 2 comprising at least one flange or screw tap or the like as connector.

4. Fluid duct according to any of the preceding claims wherein the inner part is made of a metal alloy or ceramics or rigid plastics.

5. Fluid duct according to any of the preceding claims wherein the outer part is made of convoluted nitrile rubber.

6. Fluid duct according to any of the preceding claims wherein the fluid duct is a multi-part device which comprises at least one fastening means to fixedly mount the parts of the multi-part device with each other.

7. Fluid duct according to claim 6 comprising clamps as fastening means.

8. Fluid duct according to any of the preceding claims wherein at least one end of the inner part is curved shaped.

9. Fluid duct according to any of the preceding claims wherein the flexible outer part comprises at least one flex bellow or bellow-type seal.

10. Fluid duct according to any of the preceding claims wherein the rigid inner part comprises a first inner tube and a second inner tube which interact as telescope in order to provide a degree of freedom in the axial direction of the fluid duct.

11. Fluid duct according to claim 10 wherein the first inner tube comprises a perforation which allows for controlled exchange of fluid between the inside of the first/second inner tube and an annular space arranged between the first/second inner tube and the flexible outer part of the fluid duct.

12. Fluid duct according to claim 11 wherein the controlled exchange of fluid causes a pressure balance between the inside of the first/second inner tube and the annular space which counteracts against a pressure force which tends to move the first inner tube apart from the second inner tube thus elongating the telescope.