DE102014209599A1 - Media hose and use of a media hose to monitor a machine - Google Patents

Abstract

The media hose (2) is for use at high temperatures and high pressures, especially in internal combustion engines, especially for measuring and monitoring a fluid within the internal combustion engine. For this purpose, the media tube (2) comprises an inner cavity (6), which is surrounded by a flat wire coil (4), which in turn is surrounded by a mesh (8), which is enveloped by an outer jacket (10). The structure consisting of flat wire coil (4), braid (8) and outer sheath (10) is flexurally flexible and kink-resistant, temperature-resistant to over 150 ° and resistant to media over oil, lubricants and fuels. In addition, the structure is designed for a bursting pressure greater than 10 bar.

Description

The invention relates to a media hose and its use for monitoring a machine, in particular an internal combustion engine.

The condition of machines is also partially checked by the condition of operating or working fluids of the machine. For this purpose, so-called media hoses are used, via which a connection to the fluid to be tested is produced. The media hose is therefore a type of sensor tube. This is used, for example, to check an operating pressure, etc.

There is often the problem that such media hoses are used in high-stress environments. Thus, for example, these are also used in the field of internal combustion engines, in particular of stationary or quasi-stationary large engines, for example, for marine applications (marine engines) or for power generation applications. Due to the proximity to the combustion region, the media hoses are often exposed to elevated temperatures, both from the outside by the emission of the combustion chamber as well as by the measured or derived fluids (gases) themselves. These temperatures are for example at 200 ° or above.

In addition, such media hoses must also be resistant to media especially against oils, lubricants and fuels. Due to the high pressures to be measured, for example, the exhaust pressure, they must also be designed for high operating and bursting pressures beyond. Typically, standards or classifications require a certain ratio of operating and bursting pressures.

Proceeding from this, the object of the invention is to provide a suitable for such a field of application media hose.

The object is achieved according to the invention by a media hose having the features of claim 1. The media hose is hereby designed for use at high temperatures and high pressures and in particular for use in internal combustion engines and especially for measuring and monitoring media within the internal combustion engine. The media tube has as a support member a flat wire coil which defines an internal cavity which is filled in use with the fluid. In this case, a flat wire helix is understood to mean a helix made of a steel strip, which is preferably wound at least almost to the point of impact, so that an at least largely closed sheath is created by the flat wire helix. The flat wire coil is finally surrounded by a particular closed mesh, which in turn is enveloped by an outer sheath. The entire structure of flat wire coil, braid and outer jacket is flexible in bending and at the same time kink-resistant and furthermore temperature-resistant to above 150 ° C, preferably above 200 ° C and in particular up to 260 ° C. In addition, the structure is designed for a bursting pressure greater than 10 bar. Finally, the structure is also media-resistant to oils, lubricants and / or fuels.

The property of bending flexibility with simultaneous buckling strength is achieved in particular by the flat wire helix. Due to the at least largely closed flat wire helix, individual helical sections abut each other at a bend, so that further bending is prevented and, as it were, an inherent anti-buckling protection is formed by the mutual support.

The temperature resistance is achieved by a suitable choice of material, in particular for the outer sheath, which is preferably formed as a plastic sheath consisting of high temperature resistant plastic.

The internal flat wire coil is also responsible for the resistance to high operating pressures, which also ensures the high bursting pressure. Parallel to this, however, the outer sheath is designed in such a way with regard to the selected sheath wall thickness and in dependence of the sheath material that it can withstand high pressures.

Due to the mesh as a direct intermediate layer between the flat wire coil and the outer jacket, a decoupling between these two elements is achieved, which has an advantageous effect on the desired bending flexibility. Due to the braid, the inner flat wire helix and the outer sheath are displaceable relative to each other. The closed configuration of the braid further serves for the advantageous sealing of gaps which possibly occur between individual helical pitches during a bend. As a result, the outer sheath is reliably relieved of the pressure prevailing in the inner cavity at least somewhat. Under a closed mesh is understood to mean a mesh without gaps, so the mesh has an overlap of at least almost 100%.

The media resistance is finally ensured by suitable choice of material, in particular the outer jacket. The material of the Outer shell is so designed that it is not attacked by oils, lubricants and fuels.

Flexibility is understood to mean that the media hose has a flexural modulus of <1.700 MPa. The determination of this flexural modulus of elasticity is based on the definition according to ISO 178: 2002 by means of a 3-point bending test, in which a test mandrel is moved at a defined speed against the media hose, so that a deflection takes place. From the force required for this purpose, the modulus of elasticity is determined. The modulus of elasticity of <1700 MPa applies in particular to media hoses with an outer diameter of 8 mm.

Under temperature resistant is generally the resistance of the media tube at a continuous operating temperature of z. B. 150 ° C and that over an assumed operating time of typically, for example, 20,000 hours. Over this assumed operating time, the physical properties, such as tensile strength and elongation, as well as the electrical properties must not change beyond a predetermined limit and only a few, in particular 5 percent.

By media resistance is meant that - following a storage in standard oils, such as in accordance with ISO 14752: 2007. B. IRM 902 and IRM 903 over a predetermined period of time and at a defined temperature, for example, over 72 hours at 23 ° C, the outer diameter of the media tube does not change beyond a maximum allowable limit and does not accept the medium inadmissible. The change in the outer diameter is in particular <5%.

Under bursting pressure is finally understood the pressure at which the media tube loses its functionality and is no longer tight. The bursting pressure is typically at a multiple of the operating pressure.

Conveniently, the structure consisting of flat wire helix braid and outer sheath thereby has a hose diameter which is in the range of only 5mm to 50mm and in particular in the range of less than 20mm. Such a media hose is therefore designed in the manner of a measuring tube over which only relatively small amounts of fluid flow. The kink protection, however, at the same time ensures that a volume transfer performance for which the media hose is designed, is not reduced by bending in an inadmissible manner.

In a preferred embodiment, the entire structure allows comparatively small bending radii, so that the media hose can be installed without kinking on tight installation spaces as a whole. The structure allows bending radii, which are only in the range of 5 to 10 times the diameter of the hose.

Conveniently, the flat wire coil has a thickness in the range of about 1mm. Furthermore, the flat wire coil has a width which, for example, is 1.5 to 3 times its thickness. The width of the flat wire helix is understood in each case to be the width of the steel strip used for the flat wire helix.

In addition, the flat wire coil preferably has a lay length which is only in the range of 1 to 3 times and in particular approximately 1.5 times its width. In this case, lay length is understood to mean the axial length required by the flat wire coil for a 360 ° revolution about the inner cavity. The flat wire coil is therefore arranged very steeply with respect to a longitudinal orientation. This is favorable for the desired tight bend radius.

The flat wire coil is made of steel, in particular stainless steel. This ensures high media resistance to the fluids inside the media tube.

The flat wire coil is preferably designed as an at least nearly closed coil. i.e. their individual winding sections are each adjacent to each other at least almost immediately on impact. At most, small distances in the longitudinal direction of the tube are formed between adjacent winding sections, which are for example less than 10% of the width of the flat wire helix.

The braid in a preferred embodiment is a glass fiber braid. Such is on the one hand media resistant and on the other temperature resistant. As an alternative to a glass fiber braid, it is also possible to use a braid or a wrap of a polyester yarn, a ceramic, another inorganic material or a PTFE or glass silk tape.

Such a glass fiber braid is particularly tight to produce. In addition, a good decoupling between the flat wire coil and the outer sheath is given over the glass silk braid.

The outer sheath is preferably an outer sheath of a high-temperature-resistant and media-resistant plastic. The jacket material points in particular a fluoroplastic and consists in particular of such. Such fluoroplastics are characterized by the required here good media resistance and high heat resistance.

Conveniently, the jacket material hereby is selected from FEP (fluorinated ethylene propylene), PFA (perfluoroalkoxy) or MFA (tetrafluoroethylene perfluoromethylvinyl ether). These plastic materials have been found to be particularly suitable for the intended field of application. They each have a temperature resistance of greater than 200 ° C and show good media resistance.

In particular, the jacket material consists of PTFE (polytetrafluoroethylene). This shows a particularly high temperature resistance and a very good media resistance.

The outer jacket is optionally formed by extrusion or by wrapping. He is either single-layered or multi-layered. Depending on the material used, the outer sheath is still sintered after application of the plastic material in order to form the desired properties. This is done especially with the PTFE.

An outer sheath of sintered PTFE has a total temperature resistance up to 260 ° C. In addition, sintered PTFE is also characterized by a high mechanical strength. Another advantage is the fact that PTFE does not melt. As a result, the outer jacket does not soften even at high temperatures or short-term excess temperatures and retains its good properties.

In an expedient embodiment of the outer jacket is designed for the total bursting pressure, for the entire media tube is also designed. This is preferably greater than 10 bar. In general, the media hose is typically designed for an operating pressure of several bar, for example of at least 3 bar.

In order to withstand these high pressures, the outer jacket preferably has a jacket wall thickness in the range of greater than 0.5 mm, in particular in the range of greater than 0.7 mm. The maximum jacket wall thickness is typically in the range up to 3mm. The shell wall thickness depends on the particular requirements, in particular on the operating and bursting pressure and on the material used.

In a preferred embodiment, a functional element is further laid in the inner cavity. This is, for example, an electrical functional element, in particular a wire or an optical functional element, in particular an optical waveguide. In principle, the functional element can also be designed as a cable consisting of a plurality of individual components (optical / electrical). In particular, the functional element is a sensor or data line.

The object is further achieved by the use of such a media hose with the features of claim 15. The media hose is used in particular in highly stressed areas for monitoring a machine, in particular an internal combustion engine, namely for monitoring fluids of the engine, especially for Monitoring an exhaust gas or for monitoring a combustion chamber of the engine. Under internal combustion engine is in particular a (quasi) stationary large engine, in particular diesel engine, understood, as it is used for example for power generation or as a marine engine. Such (quasi) stationary internal combustion engines typically have a power of several hundred kilowatts (for example greater than 500 kW) and in particular several megawatts.

An embodiment of the invention will be explained in more detail with reference to FIGS. In each case, in a simplified representation:

1 a cross section through a media hose as well

2 a partial side view of the media tube.

The illustrated in the figures media hose 2 comprises a flat wire coil formed as an inner support structure 4 which has an internal cavity 6 surrounds. The flat wire coil 4 turn is from a network 8th , in particular glass fiber mesh, surrounded. This braid 8th is finally from a plastic outer jacket 10 surround. The flat wire coil 4 , the braid 8th as well as the outer jacket 10 form a (shell) construction of the media tube 2 , Other elements, the structure preferably does not have.

The flat wire coil 4 consists in the embodiment of a steel strip made of stainless steel, which is wound helically. The steel strip has an approximately rectangular cross-sectional area with a width b which lies in the range between 3 and 8 mm and in particular approximately 5 mm (cf. 2 ). Furthermore, the steel strip has a thickness d1 which is in the range between 0.6 and 1.3 mm and in the exemplary embodiment at 1 mm. The lay length of the entire flat wire coil 4 is in the range of 1 to 3 times the width b of the steel strip and in particular in the range of 1 to 2 mm. The helical pitch is therefore very steep. The lay length defines the axial length in the longitudinal direction of the media tube, which requires the steel strip for a 360 ° rotation. As in particular from the 2 can be seen, have the individual turns of the flat wire coil 4 in the longitudinal direction only a small distance from each other, so that a nearly closed shell by the flat wire coil 4 is formed. The distance is maximum about in the range of thickness d1 and in the embodiment at about 1 mm.

The flat wire coil 4 defines an inner diameter D1, which is for example between 3 to 8 mm and 5mm in the embodiment. The flat wire coil 4 Therefore, has an outer diameter of about 6mm in the embodiment, which at the same time the inner diameter of the braid 8th Are defined. The braid 8th in turn, has a thickness in the range of, for example, 0.3 to 0.5 mm. Thus results for the directly on the braid 8th adjacent outer jacket 10 in the exemplary embodiment, a sheath inner diameter D3 of about 7mm. In general, this sheath inner diameter D3 is, for example, in the range between 5 and 10 mm.

The outer jacket 10 Finally, the overall wall thickness d 2 in the region is, for example, from 0.5 to 3 mm. In the exemplary embodiment, the jacket wall thickness d2 is about 1 mm, so that a total of a total hose diameter D4 of the media tube 2 in the range of about 8mm.

In the outer jacket 10 In the exemplary embodiment, this is a preferably extruded outer jacket 10 , In this case, a fluorinated ethylene propylene (FEP) is used in particular as the jacket material. Alternatively, the outer jacket 10 formed by a banded and sintered PTFE. Instead of an extrusion, the outer jacket is formed by a winding of a belt and later sintering.

• – eine sehr hohe Biegeflexibilität bis hinunter auch zu kleinen Biegeradien im Bereich beispielsweise des 5- bis 10-Fachen des Schlauchdurchmessers D4,
• – eine Knicksicherheit durch die Flachdrahtwendel 4 bis hinunter zu den kleinen Biegeradien,
• – Begrenzung des Biegeradius durch die spezielle Ausgestaltung der Flachdrahtwendel 4,
• – hohe Druckbeständigkeit gegenüber Innendrücken im Innenhohlraum 6,
• – gute Medienbeständigkeit sowohl von innen als auch von außen gegenüber Ölen, Schmier- und Treibstoffen,
• – belastbar mit Betriebsdrücken von mehreren bar, insbesondere von 1 bis 5 bar,
• – ausgelegt für Berstdrücke im Bereich von größer 10 bar Überdruck,
• – hohe Temperaturbeständigkeit von größer 150°, vorzugsweise von größer 200°. Bevorzugt weist der Medienschlauch dabei eine Temperaturbeständigkeit bis hin zu 260° auf.

The structure described here consisting of flat wire coil 4 , Braid 8th as well as outer jacket 10 has the following properties in an advantageous embodiment:

• A very high bending flexibility down to even small bending radii in the range of, for example, 5 to 10 times the diameter of the hose D4,
• - A buckling security by the flat wire coil 4 down to the small bending radii,
• - Limitation of the bending radius by the special design of the flat wire coil 4 .
• - high pressure resistance to internal pressures in the internal cavity 6 .
• - good media resistance both from the inside and the outside to oils, lubricants and fuels,
• - Loadable with operating pressures of several bar, in particular from 1 to 5 bar,
• - designed for burst pressures in the range of greater than 10 bar overpressure,
• - High temperature resistance of greater than 150 °, preferably greater than 200 °. Preferably, the media tube has a temperature resistance up to 260 °.

Due to this special structure is therefore the media hose 2 suitable for use in highly stressed areas, for example, an internal combustion engine for monitoring fluids, especially gases of the internal combustion engine itself. The media hose 2 is therefore preferably connected to an internal combustion engine during operation, for example in the region of an exhaust pipe or directly for establishing a connection with the combustion chamber of the engine directly. It serves to monitor or measure the fluids contained in the combustion chamber or the combustion process as such.

In the figure is still a in the inner cavity 6 arranged strand-shaped functional element 14 represented, which is designed for example as a sensor or data line. The functional element 14 is for example an electrical wire, a cable with multiple components or an optical fiber. The functional element 14 lies in the inner cavity 14 Preferably, a loose, preferably without being attached to the (shell) structure. It is understood that the functional element 14 itself must also have a high temperature resistance and high media resistance, since this functional element 14 in the inner cavity 6 suspended fluid is exposed during operation.

LIST OF REFERENCE NUMBERS

2

media tube

4

Strip coil

6

internal cavity

8th

weave

10

outer sheath

14

functional element

D1

Inner diameter

D3

Coat inside diameter

D4

Hose diameter

d1

Thick flat wire coil

d2

Coat thickness

b

Wide flat wire coil

Claims (16)

Media tube ( 2 ) for use at high temperatures and high pressures, especially in internal combustion engines, especially for measuring and monitoring a fluid within the internal combustion engine, comprising an internal cavity ( 6 ), which of a flat wire coil ( 4 ), wherein the flat wire coil ( 4 ) of a mesh ( 8th ) surrounded by an outer shell ( 10 ), wherein the structure of flat wire coil ( 4 ), Braid ( 8th ) and outer jacket ( 10 ) bend-flexible and kink-resistant, temperature-resistant up to more than 150 ° C, media resistant to oil, lubricants and fuels and designed for a bursting pressure greater than 10bar. Media tube ( 2 ) according to the preceding claim, in which the structure has a hose diameter (D4) which is in the range of 5 mm to 50 mm and in particular in the range of less than 20 mm. Media tube ( 2 ) according to the preceding claim, in which the flat wire coil ( 4 ) has a thickness (d1) in the range of about 1 mm. Media tube ( 2 ) according to one of the preceding claims, in which the flat wire coil ( 4 ) has a lay length in the range of 1 to 3 times a width (b) of the flat wire coil ( 4 ) and in particular at 1.5 times the width (b). Media tube ( 2 ) according to one of the preceding claims, in which the flat wire coil ( 4 ) is formed as an at least almost closed helix. Media tube ( 2 ) according to one of the preceding claims, in which the braid ( 8th ) is a glass fiber braid. Media tube ( 2 ) according to one of the preceding claims, in which the outer jacket ( 10 ) has a fluoroplastic as a shell material. Media tube ( 2 ) according to one of the preceding claims, in which the jacket material of the outer jacket ( 10 ) is selected from FEP, PFA and MFA. Media tube ( 2 ) according to one of the preceding claims, in which the jacket material of the outer jacket ( 10 ) consists of PTFE. Media tube ( 2 ) according to one of the preceding claims, in which the outer jacket ( 10 ) is sintered. Media tube ( 2 ) according to one of the preceding claims, in which the outer jacket ( 10 ) is designed for the bursting pressure. Media tube ( 2 ) according to one of the preceding claims, in which the outer jacket ( 10 ) has a shell wall thickness (d) in the range of greater than 0.5 mm to 3 mm. Media tube ( 2 ) according to one of the preceding claims, wherein in the inner cavity ( 6 ) a functional element ( 14 ). Media tube ( 2 ) according to the preceding claim, in which the functional element ( 14 ) is a wire, a cable or a fiber optic cable and in particular a sensor or data line. Using the media tube ( 2 ) according to one of the preceding claims for monitoring a machine, in particular an internal combustion engine, in which via the media hose ( 2 ) is connected to an interior of the machine for checking the state of a fluid inside.  Use according to the preceding claim for monitoring an exhaust gas or for monitoring a combustion chamber.

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