Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B37/00—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00
  • F04B37/02—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for evacuating by absorption or adsorption
  • F04B37/04—Selection of specific absorption or adsorption materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S10/00—Solar heat collectors using working fluids
  • F24S10/40—Solar heat collectors using working fluids in absorbing elements surrounded by transparent enclosures, e.g. evacuated solar collectors
  • F24S10/45—Solar heat collectors using working fluids in absorbing elements surrounded by transparent enclosures, e.g. evacuated solar collectors the enclosure being cylindrical
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
  • F24S40/40—Preventing corrosion; Protecting against dirt or contamination
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
  • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
  • F24S40/40—Preventing corrosion; Protecting against dirt or contamination
  • F24S40/46—Maintaining vacuum, e.g. by using getters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0258—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with means to remove contaminants, e.g. getters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/40—Solar thermal energy, e.g. solar towers
  • Y02E10/44—Heat exchange systems

Definitions

• the present invention relates to improved solutions for integrating hydrogen getter in powder form within hydrogen sensitive devices, and hydrogen sensitive devices employing such improved solutions.
• One of the most interesting hydrogen sensitive devices category where the present invention finds a useful application is that of receiving tubes for solar collectors.
• getter alloys and of shielding solutions are sufficient for meeting the current requirements in the field of the receiving tubes for solar collectors, but not for assuring the fulfilment of the demands from the new generation of receivers, both in terms of working temperature, which is foreseen that could be higher than 500°C, and in terms of hydrogen capacity of the getter alloy inside the receiving tube of the collector which, in the absence of effective shielding solutions, can be at a temperature very close to the working temperature of the tube.
• the embrittlement typically starts when the getter alloy has absorbed about 2500
• Another problem of using the getter material in consolidated form is that its absorption speed is reduced with respect to its use in powder form, since in the first case the total active getter surface area is significantly less readily available.
• Aim of the present invention is to provide a solution able to overcome the SIB BW560M-TE drawbacks present in the prior art and enabling the use of getter materials in powder forms within hydrogen sensitive devices.
• the invention consists in a hydrogen getter system comprising a metallic mesh with closed extremities containing getter material powders, characterized in that:
• the metallic mesh openings are comprised between 10 and 200 micron;
• the getter material powders have dimensions comprised between 50 and 3000 micron;
• the ratio between the smallest dimension of the getter material powders and the mesh size openings is 2 or higher.
• such ratio between the smallest dimension of the getter material powders and the mesh size is at least 3.
• Figure 1 represents a first embodiment of a getter system according to the present invention
• Figure 2A represents a getter system according to a second alternative embodiment of the invention and figure 2B shows its positioning within a sensitive device;
• Figure 3A represents a getter system according to a third alternative embodiment, with figure 3B showing its positioning within a sensitive device.
• mesh size it is intended the dimension of the openings of the net whose purpose is the getter powders retaining and that allows an easy access to H 2 for an efficient and fast removal from the internal environment of the sensitive device.
• Such metallic meshes are characterized by a typical number, that is the number of wires per unit of length (the inch being typically used as unit of length) whereby with a 140 mesh is intended a mesh having 140 wires in one inch.
• the particle size of the powders is typically selected by means of two sieving operations after grinding of the getter alloy.
• the particles that have larger dimension are discarded; those are the ones that do not pass through a first sieve with opening SI .
• This selects all the particles having a sieving diameter below SI . Choosing particles having dimensions below a certain limit SI guarantees that each getter particle has a sufficiently high surface to volume ratio, i.e. a free surface available for the quick 3 ⁇ 4 sorption.
• these powders are subjected to a second sieving operation using a sieve with opening S2 ( ⁇ S1), where in this case all the fraction passing through the sieve is discarded. So these operations provide powders having a sieving diameter comprised between SI and S2.
• the correct dimensioning, or, to be more precise, the correct coupling between the metallic mesh of the getter device and the size of the getter powders therein contained is essential for the successful employ of the getter material in powder form within the sensitive device, with particular reference to receiving tubes for solar collectors.
• the sorption speed of the getter material is one of the factor influencing the overall sorption speed of the getter system, keeping into SIB BW560M-TE account the impact on such fundamental parameter given by the retaining mesh/net of the getter system itself.
• the getter devices according to the present invention are typically manufactured starting from a rectangular metallic mesh that is overlapped on its shortest side and soldered or locally welded.
• the extremities of the net need to be closed separately, and such operation may be done through soldering or a localized welding of the end portion of the mesh or through suitable plug crimping of said portion.
• the filling with the getter material powders is typically made after the cylinder is formed, before the final closing of the end portion of the mesh.
• a rolled mesh typically spans from 100 to 500 mm in length and has a diameter comprised between 5 and 25 mm.
• the two ends of the metallic mesh once closed, are coupled together via coupling means to give the getter system an annular configuration.
• a resilient means such as a spring is provided and joined to the other end.
• the coupling of the ends may also be made by coupling means running alongside or inside the metallic mesh of the getter system.
• FIG. 1 shows a getter system 10 according to the present inventions, formed by a metallic mesh 11 containing a getter material in form of powders (not shown). Both ends of the mesh are closed by plugs 12, 12', that are coupled together by a spring 13.
• the annular configuration of the getter system allows to easily mount it within sensitive devices of cylindrical geometry, such in the case of receiving tubes.
• the getter device is placed on the outer surface of the inner tube.
• FIG. 2A a getter system 21 is shown, with an elastic, superelastic or shape memory wire or strip 22 running alongside the mesh and having the coupling function between the extremities of the getter system.
• the wire is in the internal part of the mesh.
• Figure 2B shows the getter system installed within a receiving tube for solar collector 20, simply depicted showing two of its main constituents, the internal tube 23 where the oil (not shown) flows, and the external tube 24 that constitutes the case of the receiving tube.
• the getter device is compressed to reduce the radius, and released after having placed it on the sensitive device component.
• FIG. 3 A a getter system 31 is shown, with an elastic, superelastic or shape memory wire or strip 32 running alongside the mesh. Also in this case the wire is in the internal part of the mesh and has the coupling function between the extremities of the getter system, meaning that the wire and its displacement influences the reciprocal position of the extremities.
• Figure 3B shows the getter system installed within a receiving tube for solar collector 30, also in this case schematically represented depicting only two of its main constituents, the internal tube 33 where the oil (not shown) flows, and the external tube 34 that constitutes the case of the receiver.
• the elastic means comprises thermal responsive element or elements, such as shape memory alloy or superelastic elements, and the force exerted solely by the shape transition of the alloy consequent to its heating. It can also be provided a combined system, where for example standard elastic means, such as mechanical springs, are used for a mild anchoring of the getter device on the component, while the shape memory element provides for an extra force firmly holding the getter system in place, when the sensitive device is in use, as a consequence of the rise in temperature during operation.
• standard elastic means such as mechanical springs
• Getter material powders useful for the present inventions are for example the ones described in US patent 3,203,901 (Zr-Al alloys), US patent 4,306,887 (Zr-Fe alloys), US patent 5,961,750 (Zr-Co-Rare earths alloy).
• For hydrogen sorption, particularly at high temperatures it is also known the use of yttrium alloys, as described in the international patent applications WO 2007/148362 and WO 2007/099575, and in the above mentioned Italian patent application MI2009/A00410.
• the above mentioned getter alloys are the ones preferably used with the present invention, but any hydrogen getter alloy used in powder form may be employed with the inventive concept disclosed.
• the metallic mesh openings are comprised between 10 and 200 micron; - the getter material powders have dimensions comprised between 50 and
• the ratio between the smallest dimension of the getter material powders and the mesh size is 2 or higher.
• the hydrogen sensitive device is a receiver tube for solar collectors
• the getter system comprises elastic means, such as springs, to enable its fixing by elastic force onto a wall of the receiver.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Gas Separation By Absorption (AREA)
• Powder Metallurgy (AREA)

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• 2010
  • 2010-04-22 EP EP10425130A patent/EP2325575A1/en not_active Ceased
• 2011
  • 2011-03-28 JP JP2013505382A patent/JP2013531772A/ja active Pending
  • 2011-03-28 CN CN201180020081.6A patent/CN102859291B/zh active Active
  • 2011-03-28 US US13/637,965 patent/US20130025585A1/en not_active Abandoned
  • 2011-03-28 EP EP11710212A patent/EP2494280A1/en not_active Ceased
  • 2011-03-28 WO PCT/EP2011/054688 patent/WO2011131456A1/en not_active Ceased
• 2012
  • 2012-10-17 IL IL222502A patent/IL222502A/en active IP Right Grant

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