The invention refers to a sealing sleeve with leakage detection comprising an absorbing layer and a sensor arrangement, wherein the absorbing layer is configured to be attached to a surface of an article containing a fluid, and to a hose assembly with a connector comprising a nipple and a socket, wherein an end of a hose is slipped on the nipple and the socket is adapted to establish a fluid tight connection of the hose and the nipple, wherein a sealing sleeve is attached at an intersection of the socket and the hose.

For hydraulic hose assemblies and, more generally, for any fluid containing or conveying article, there is a potential risk of leakage of the contained or conveyed fluid. The most critical locations for the appearance of a leakage are connections of two fluid conveying parts, like, for example, at a hose-fitting interface. A leakage can be detect visually when the fluid appears on a surface of the fluid containing or conveying article, for example, on the hydraulic hose or on the fitting.

According to WO 2010/004418 Al, a hose fault detection system includes a hose assembly with a fault detector. The hose assembly includes a first conductive layer, a second conductive layer, and an intermediate layer that is disposed between the first and second conductive layers. The fault detector is configured for detecting a change of an electrical characteristic of at least one of the first and second conductive layers of the hose, which is assumed to be caused by a fault of the hose assembly, for example, when the two conductive layers are short-circuited by leaking fluid.

However, at the moment the leakage can be detected, the fluid either is already in contact with the environment or the contact is at least imminent, such that a potential environmental contamination cannot be obviated. Further, the hose assembly with fault detection is expensive in production with the conductive layers arranged surroundingly and radially spaced to each other. Furthermore, in case of a malfunction of the detection circuit, the complete hose has to be exchanged, in order to restore the fault detection functionality. An objective of the present invention is to provide a leakage detection at a fluid containing or conveying article, wherein the fluid leakage is detected well in advance before a contaminating contact with environment occurs. The objective is achieved by a sealing sleeve and by a hose assembly with such a sealing sleeve, according to the respective independent claims. Preferred and advantageous embodiments are subject to the dependent claims.

The sealing sleeve with leakage detection according to the invention comprises an absorbing layer and a sensor arrangement, wherein the absorbing layer is configured to be attached to a surface of an article containing a fluid and to absorb the fluid in case of a leakage, and wherein the sensor arrangement is configured to detect a level of saturation of the absorbing layer with the fluid. An advantage of the sealing sleeve according to the invention is the absorption of the leaking fluid by the absorption layer, which is further detected by the sensor arrangement as the absorbing layer gets gradually saturated with the fluid. Notice of the detection can be given in advance of a contaminating contact of the fluid with environment. Thus, the article, like a hose assembly, for example, may be replaced or repaired before the leakage leads to environmental contamination. A further advantage of the sealing sleeve according to the invention is its basic structure, which makes it easy to attach and allows a production of the sealing sleeve at low costs.

According to a preferred embodiment a thickness of the absorbing layer increases with an amount of absorbed fluid. In particular, the absorbing layer consists of an EPDM rubber, i.e. an ethylene propylene diene monomer (M-class) rubber.

According to a further preferred embodiment the sensor arrangement comprises a capacitive humidity sensor. The sensor arrangement preferably comprises two electrodes with at least a portion of the absorption layer acting as a dielectric between the two electrodes.

According to a further preferred embodiment the two electrodes are attached to an outer side of the absorption layer, opposite to a side facing the surface of the article. That means the electrodes are arranged next to each other, aligned along the surface of the article. In terms of a hose assembly, typically comprising a circular cross-section, which means the two electrodes are arranged surrounding the hose assembly, distanced in a direction along a longitudinal axis of the hose assembly, which refers also to the direction of flow of the fluid inside the hose assembly. That means further that the two electrodes both are arranged at an identical distance to the surface of the hose assembly.

According to a further preferred embodiment the sensor arrangement is configured to transmit a signal if the level of saturation changes. The signal transmission may be carried out by sending the signal through a wire, or via a wireless connection. The sensor arrangement is preferably configured to transmit the signal prior to an emersion of the fluid from the absorption layer, i.e. well in advance before a full saturation of the absorption layer is reached. According to a further preferred embodiment the sealing sleeve is confected in terms of a strip. The sealing sleeve strip is advantageously very easy to attach to any kind of fluid containing article, for example, around a hose assembly. It is even possible to adjust the length of the sealing sleeve strip to different hose diameters, or to level out different hose diameters with a flexible strip. More preferably, the sensor arrangement comprises two electrodes, wherein the electrodes are arranged in parallel along the strip.

According to an alternatively preferred embodiment the sealing sleeve is preassembled on a hose connector. Pre-assembly advantageously facilitates the attachment of the sealing sleeve and further prevents neglect to attach the sealing sleeve. More preferably, the sensor arrangement of the preassembled sealing sleeve comprises two electrodes provided as annular rings arranged in parallel around the absorption layer.

According to a further preferred embodiment the sealing sleeve further comprises at least one protective layer covering the absorption layer and the sensor arrangement. The protective layer is, for example, a layer made of a compound that is a blend of NBR and PVC, i.e. nitrile butadiene rubber and polyvinyl chloride. As alternative to the NBR and PVC blend, also an NBR and CR (chloroprene) compound is preferably used for the protective layer. The protective layer protects the absorption layer and the sensor arrangement from environmental influences. It is furthermore preferable to provide an additional metal layer as a kinking protection, if the application requires such an additional protection.

Another object of the invention is a hose assembly with a connector comprising a nipple and a socket, wherein an end of a hose is slipped on the nipple and the socket is adapted to establish a fluid tight connection of the hose and the nipple, wherein a sealing sleeve according to the present invention is attached, preferably at an intersection of the socket and the hose.

The sealing sleeve according to the invention is advantageously adapted to both detect and prevent a leakage on the hose assembly. At the hose-fitting intersection of the hose assembly, the sealing sleeve works most efficiently, as a leakage occurs in the most cases at the intersection. To avoid leakage the sealing sleeve is assembled around the hose-fitting intersection of the hose assembly. It is preferably connected via a stripe system, or alternatively, directly on the socket, for example as a preassembled part. When attached to the hose assembly the sealing sleeve will absorb fluid, like hydraulic oil, leaking from the hose assembly at the hose-fitting interface. The fluid is absorbed by the absorption layer, which is for example realized as an inner EPDM-layer of the sealing sleeve. The EPDM is swelling when getting in contact with hydraulic oil and will absorb the oil in doing this. In this way, advantageously no hydraulic oil is passed into the environment. When the EPDM layer is swelled with hydraulic oil the sensor arrangement, for example, a capacitive humidity sensor, will sense the change in humidity in the absorption layer and will give a signal to give notice that a leakage from the hose assembly will appear in the near future. The hose assembly according to the invention thus advantageously allows to avoid environmental hazards due to hose assembly leakage, and further also to optimize a run time of a hose assembly, as it does not have to be exchanged preventively. Furthermore, the sealing sleeve according to the invention may advantageously be used in combination with a hydraulic hose condition monitoring system that detects failure-related events within a hose to detect also leakage failures. The invention is now further explicated with respect to the attached drawings. The information refers to the sealing sleeve according to the invention, as well as to the hose assembly. The described embodiments are exemplary and do not limit the scope of the invention. In the Figures,

Figure 1 illustrates schematically a hose assembly with an embodiment of a sealing sleeve according to the invention;

Figure 2 illustrates schematically a composition of the sealing sleeve according to Figure 1 in a cross section; Figures 3A through 3C illustrate schematically a procedure of attaching an alternative embodiment of a sealing sleeve to a hose assembly.

Figure 1 illustrates schematically a representation of a hose assembly 1 with an embodiment of a sealing sleeve 10 with leakage detection according to the invention. The hose assembly 1 comprises a connector 3 with a nipple 4 and a socket 5, and an end of a hose 6. The end of the hose 6 is slipped on the nipple 4 and the socket 5 is adapted to establish a fluid tight connection of the hose 6 and the nipple 5. The sealing sleeve 10 is attached at an intersection 7 (Fig. 3A) of the socket 5 and the hose 6, where a leakage of the hose assembly 1 is expected.

The sealing sleeve 10 with leakage detection is further explicated with respect to Figure 2 illustrating a cross sections through the sealing sleeve 10, which comprises an absorbing layer 11 and a sensor arrangement 12, wherein the absorbing layer 11 is configured to be attached to a surface 2 of an article 1 containing a fluid, in this embodiment the hose assembly 1. The absorbing layer 11 will absorb the fluid in case of a leakage, and the sensor arrangement 12 is configured to detect a level of saturation of the absorbing layer 11 with the fluid. A thickness of the absorbing layer 11 increases with an amount of absorbed fluid to facilitate the sealing function of the sealing sleeve. For example, if the hose assembly is used to convey hydraulic oil, the absorbing layer 11 may consist of an EPDM rubber. The detection of the level of saturation of the absorbing layer 11 with the fluid is preferably performed with a capacitive humidity sensor, which is advantageously realized by the sensor arrangement 12, which, in the particular embodiment comprises two electrodes 14 with at least a portion of the absorption layer 11 acting as a dielectric between the two electrodes 14. This is achieved by attaching the two electrodes 14 to an outer side 15 of the absorption layer 11, opposite to a side 16 facing the surface 2 of the socket 5 connected to the hose 6. Preferably, the sealing sleeve 10 further comprises at least one protective layer 17 covering the absorption layer 11 and the sensor arrangement 12. The sealing sleeve 10 according to Figure 1 may advantageously be preassembled on the socket 5 of the hose connector 3. The two electrodes 14 of the sensor arrangement 12 would then be provided as annular rings arranged in parallel around the absorption layer 11.

An alternate embodiment of the sealing sleeve 10 is illustrated schematically in Figure 3 A through 3C, which depict three phases of a procedure of attaching the sealing sleeve 10, which is confected in terms of a strip, to the hose assembly 1. The two electrodes 14 of the sensor arrangement 12 are arranged in parallel along the strip. In Figure 3 A, the sealing sleeve strip 10 is arranged around the intersection 7 of the socket 5 and the hose 6, which is denoted by the curved arrow P. The cross section of the sealing sleeve strip 10 according to Figure 2, is depicted by a hatched area in Figure 3A. In Figure 3B, the sealing sleeve strip 10 almost surrounds the circumference of the hose assembly 1. Fasteners 18 attached to one end of the strip 10 carry catches 19, which are configured to be connected to respective holding fixtures 20 on the other end of the strip 10. Figure 3C shows the fastened sealing sleeve strip 10 in its final arrangement on the hose assembly 1.

Reference Numerals

1 Article containing a fluid, hose assembly

Surface

3 Connector

4 Nipple

5 Socket

6 End of hose

7 Intersection

10 Sealing sleeve

11 Absorbing layer

12 Sensor arrangement

14 Electrodes

15 Outer side

16 Inner Side

17 Protective Layer

18 Fastener

19 Catch

20 Holding Fixture

P Arrow