Technical Field

[0001 ] The present invention generally relates to a cross-flow filter and cross-flow filter sheets.

Background Art

[0002] Traditional Cross-Flow Filters use hollow capillary or tubular membrane manufactured from various materials, raw unfiltered product is pumped in a semi closed loop through the lumen at a controlled velocity and pressure. Turbulent flow is preferred as this helps to keep particulates in suspension, reducing the effect of membrane fouling.

[0003] Titanium is recognised to be a superior strong, lightweight and corrosion resistant material that can be used as a membrane.

[0004] Traditional methods of producing a titanium tubular membrane are via isostatic pressing, whereby titanium powder is isostatically pressed at high pressure on a mandrill to form short lengths of green strength tubes and is then sintered in a high vacuum or flowing gas furnace.

[0005] Using these traditional methods of forming a titanium membrane limiting factors are the ability to handle green membrane in any reasonable length, diameters tend to be in the range of 12mm and larger, with wall thicknesses of about 1 .5mm minimum and lengths of 600mm maximum.

[0006] However titanium and titanium alloys are a difficult material to process due to their affiliation with oxygen and oxides, especially at elevated temperatures.

Summary of Invention

[0007] It is an object of this invention to provide to ameliorate, mitigate or overcome, at least one disadvantage of the prior art, or which will at least provide the public with a practical choice.

[0008] In a first aspect, the present invention provides a cross-flow filtration assembly including: a pump;

a first fluid for filtering; and

a plurality of filtering plates;

wherein the plurality of filtering plates comprise a titanium membrane formed by supersonic particle deposition.

[0009] Preferably, the plurality of plates are arranged so that a feed stream comprising fluid and particulate material is adapted to be fed tangentially across the plates so that the particulate material is collected as a retentate on one side of each of the plates and a filtrate is expressed from the opposite side of each of the plates.

[0010] Preferably, the titanium membrane is between 0.1 mm and 3mm thick.

[001 1 ] Preferably, the titanium membrane is between 0.1 mm and 0.5mm thick.

[0012] Preferably, the supersonic particle deposition is performed onto a resin layer on the plate.

[0013] Preferably, the resin layer comprises metal or glass.

[0014] Preferably the resin layer is formed on a template and dried prior to the supersonic particle deposition.

[0015] Preferably, the titanium membrane has an open area of between 20% and 60%. [0016] Preferably one side of the titanium membrane is fluted.

[0017] Preferably the fluting is formed as a result of varied thickness deposits via the supersonic particle deposition.

[0018] In accordance with a second embodiment, the present invention provides:

a method of forming a titanium membrane plate for use in a cross-flow filtration system;

wherein a resin layer is sprayed onto a template and dried;

a layer of titanium powder is coated onto the dried resin layer using supersonic particle deposition to form the titanium membrane plate; and

the titanium membrane plate and dried resin layer are dipped in a chemical bath that dissolves the resin layer leaving the titanium membrane plate. [0019] Preferably, the resin layer comprises metal or glass.

[0020] Preferably, a coating is applied to the titanium sheet after the sheet is removed from the chemical bath to create the desired pore range.

[0021 ] Preferably, fluting is created on the titanium sheet via controlled deposition of the titanium powder during supersonic particle deposition.

[0022] Preferably, the titanium sheet has an open area of between 20% and 60%.

[0023] Preferably the fluting is formed as a result of varied thickness deposits via the supersonic particle deposition.

[0024] Other aspects and advantages of the invention will become apparent to those skilled in the art from a review of the ensuing description.

Brief Description of the Drawings

[0025] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a cross-flow filtration assembly of a first embodiment of the present invention.

[0026] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

Description of Embodiments

[0027] Broadly, the present invention provides a cross-flow plate micro filter 10 including a plurality of titanium membrane plates 18 formed via supersonic particle deposition. [0028] Although the present invention will be described as a cross-flow plate microfilter, the skilled addressee will recognise that the present invention equally applies to a cross-flow tubular filter where the tubular element is comprises the titanium membrane plate 18 formed into a tubular structure.

[0029] Referring to Figure 1 , Feed stream 24 of a mixture of fluid and particulates is fed into the cross-flow plate micro filter 10 from pump 26. The feed stream is then directed tangentially across titanium membrane plates 18 on the fluted surface 20 through tangential flow 14. Retentate collects and flows on the fluted surface 20 to be collected distal to the feed stream 24 and pumped out as retentate outflow 22.

[0030] In one embodiment the tangential flow 14 causes scrubbing of plates to minimize the collection of retentate on the surface of the titanium membrane plates 18.

[0031 ] In one embodiment the retentate is fed back into the cross-flow plate micro filter 10 as part of the feed stream 24.

[0032] Filtrate 12 passes through the titanium membrane plates 18 and is removed from the system through filtrate stream 16.

[0033] The titanium membrane plates 18 are formed as follows.

[0034] A template is coated in a resin or comparable material and allowed to dry. After the resin has dried it is removed from the template. In a chamber, the dried resin is coated with fine particles of titanium powder by way of Supersonic Particle Deposition which bonds the titanium powder particles together to form the titanium membrane plate 18 by entraining particles in a supersonic gas velocity stream. The formed titanium membrane plate includes pores to allow fluid to flow through it.

[0035] Following Supersonic Particle Deposition, when the titanium powder has fused to form the titanium membrane plate 18, the plate is submerged in a chemical bath where the resin is dissolved leaving only the titanium membrane plate.

[0036] The titanium membrane plates 18 serve as filtration plates. This can be rectangular, square, circular or any other shape as understood by the skilled addressee.

[0037] The resin can be formed into any shape that the titanium membrane plate 18 is intended to take. In one embodiment shape of the template defines the shape of the resin. In an alternative embodiment the resin is 3D printed to define the shape of the resin.

[0038] In one embodiment the resin includes glass or metal elements blended into it to increase the hardness of the resin when it has set. In one embodiment the metal or glass.

[0039] In one embodiment, the resin is a UV set or quick set resin.

[0040] As one side of the resin is flat from its formation on a template, one side of the titanium membrane plates 18 is smooth and the surface of the other side depends on the Supersonic Particle Deposition.

[0041 ] The chamber within which the resin is placed for Supersonic Particle Deposition is sealed and treated under pressure and temperature within to provide an open area of the titanium membrane plate 18 of 20 to 60%. In one embodiment the pressure within the chamber is between 7 bar and 30 bar. In one embodiment the temperature within the chamber is between 300 and 900^3.

[0042] The Supersonic Particle Deposition of titanium powder provides a thickness of between 0.1 mm and 3mm to the titanium membrane plates 18. In one embodiment a thickness of 0.5mm is achieved for the titanium membrane plates 18.

[0043] In one embodiment, the Supersonic Particle Deposition is robotically controlled to form the fluting of the fluted surface 20. The fluting is formed by depositing thicker layers of titanium powder.

[0044] In one embodiment, after the titanium membrane plate 18 is removed from the chemical bath it is coated to ensure that the desired pore range on the titanium membrane plate 18 is achieved.

Variations and Modifications

[0045] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein.

[0046] Reference to positional descriptions, such as lower and upper, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[0047] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0048] Also, future patent applications maybe filed in Australia or overseas on the basis of, or claiming priority from, the present application. It is to be understood that the following provisional claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application. Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention or inventions.