PATENTS

15Sealing Technology September 2005

Externally activated seal system for wellheadApplicant/Inventor: B.H. VanBilderbeek (USA)A method and apparatus for a sealassembly for a unitized wellheadsystem for land or platform appli-cations is described in this patent.The invention is particularlyapplicable to seal between concen-tric strings in the wellhead wherethe seal is activated via an external,non-invasive seal energizing systemand uses metal-to-metal seals withfinely-controlled contact stressesfor lock-down casing and tubinghangers. The compression systemhas a compression flange (14) and acompression wedge (15). The com-pression flanges are rings withtapered inner surfaces that mate

with the tapered outer surfaces ofthe compression wedges. Axialmovement of the compressionflanges over the compressionwedges compresses the compres-sion wedges inwards, in turn com-pressing a portion of the wellheadhousing (1) inwards, within theelastic range. The compression sys-tem may be configured with a splitspacer ring (16) between the com-pression wedge and the wellheadhousing. The split spacer rings haveminimal hoop stiffness, and simplypass the radial contact loads fromthe compression wedge into thewellhead housing.Patent number: WO 2005/065292Publication date: 21 July 2005

Applicant: MTU Aero EnginesGmbH, Germany.

The invention relates to a layersystem for an abradable rotor/sta-tor seal of a turbine, especially gasturbines. The abradable seal layersare designed to be fitted to boththe stator housing and the rotor ofthe turbine which are preferablymanufactured from a titaniumbase alloy or a titanium-aluminumalloy. The layer system has anabradable coating comprising atleast two layers, a first, inner layerof the coating being harder than asecond, outer layer. The layers of

the abradable coating are madefrom a ceramic material.According to the invention, thelayers (16, 17, 18) of the coating(13) are graded in such a mannerthat the porosity varies across thethickness of the layers. The first,inner layer (16) has a lower poros-ity or may be denser than the sec-ond, outer layer (17). The innerlayer also provides a titanium fire-proof coating.Patent number: WO 2005/071228Inventors: M.Däubler andK.SchweitzerPublication date: 4 August 2005

Disposable transducer sealApplicant: Liposonix Inc, USAThis invention pertains to a sealingdevice for retaining a coupling fluidsuch as degassed water within anultrasound transducer housing.Ultrasound transducers require acoupling medium to connect thetransducer to a patient in order tominimize the reflection and refrac-tion of ultrasound waves whenthose waves cross a border betweentwo materials of similar acousticproperties. One of the biggestissues in coupling transducers to apatient either for a diagnostic ultra-sound device, or a therapeuticultrasound device, is the presenceof air. It is an objective of the pre-sent invention to provide for a sealthat is both inexpensive to manu-facture, and that can be quicklyand easily installed into a transduc-er housing. The seal is also dispos-able so reuse and re-sterilizationconcerns can be avoided. Theretainer (592) of the disposable

transducer seal (590) has an annu-lar configuration. The membrane(594) is drawn tightly around theretainer. The membrane is drawntightly about the retainer and heldin place.Patent number: WO 2005/065422Inventors: C.S. Desilets et al.Publication date: 21 July 2005

Cross-section of the metal wellhead casing seal assembly that is actuat-ed by compression wedges to contract the casing diameter, from WO2005/065292.

Section of the disposable ultra-sound transducer seal arrange-ment, from WO 2005/065422.

Seal with non-contact adjacent deflector ringsApplicant: FAG Kugelfischer AG,GermanyThis patent relates to a bearingshaft seal with a non-contactdeflector ring arrangement. Theseal is mounted on a stationarydeflector ring (3). A rotating hub(10) has a number of deflectorrings on the outside diameter (11,12) which are designed so that

they do not come into contactwith the outer deflector ring.Between the deflector ring lips arehollow cavities (19, 23).Patent number: WO2005/059412Inventors: E. Hartmann and W.WalterPublication date: 30 June 2005

The bearing sealwith non-contact-ing deflector ringsdescribed in WO2005/059412.

Layer system for a rotor/stator seal of gas turbines