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AssigneeInvensys Apv A/S
InventorsKnud Thorsen, Preben Koeningsfeldt, Ole Poulsen
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The invention relates to a scraped surface heat exchanger (100) comprising a heat exchanging wall (20) having an cylindrical inner surface (21) with a radius (R+δ), a shaft (10) being rotatable mounted inside of and concentrically to the inner surface (21) of the heat exchanging wall (20) and having at least one gap portion (10A) with an outer surface (11) and a radius (R), and at least one scraping member (40) supported by the shaft (10) and extending to the inner surface (21) of the heat exchanger wall (20), characterised in that the at least one or che gap portions (10A) with an outer surface (11) and a radius (R) extend over at least 60% of the circumference of the shaft (10).
1-36. (canceled)
A scraped surface heat exchanger comprising:
The scraped surface heat exchanger of claim 1, wherein in the ratio of the radius of the at least one gap portion to the gap between the inner surface of the heat exchanger wall and the outer surface of the at least one gap portion is at least 6.
The scraped surface heat exchanger according to claim 1, wherein the gap (δ) between the inner surface of the heat exchanger wall and the outer surface of the at least one gap portion is less than 15 mm.
The scraped surface heat exchanger according to claim 1, wherein the inner surface of the heat exchanger wall comprises a protective layer.
The scraped surface heat exchanger according to claim 1, wherein the at least one or the gap portions with an outer surface and a radius (R) extend over at least 60% of the circumference of the shaft.
The scraped surface heat exchanger according to claim 1, wherein the scraped surface heat exchanger is operated with a speed of the shaft of less than 900 RPM.
The scraped surface heat exchanger according to claim 1, wherein the ratio (R/((R+δ)−R)) of the radius (R) of the at least one gap portion to the gap (δ) between the inner surface of the heat exchanger wall and the outer surface of the at least one gap portion is at least 7, preferably at least 10, more preferably at least 13 and most preferably at least 16.
The scraped surface heat exchanger according to claim 1, wherein the gap (δ) between the inner surface of the heat exchanger wall and the outer surface of the at least one gap portion is less than 13 mm, preferably less than 10 mm, more preferably less than 7 mm, even more preferably less than 5 mm and most preferably less than 3 mm.
The scraped surface heat exchanger of claim 1, wherein the at least one of the gap portions with an outer surface and a radius (R) extend over at least 70%, preferably at least 75%, more preferably at least 80% and most preferably at least 85% of the circumference of the shaft.
The scraped surface heat exchanger according to claim 1, wherein the inner surface of the heat exchanger wall is hard chromed.
The scraped surface heat exchanger according to claim 1, wherein the shear rate (D=v(R)/δ= 1/30*π*n*R/δ) is less than 500/s, preferably less than 400/s, more preferably less than 350/s and most preferably less than 300/s.
The scraped surface heat exchanger according to claim 1, wherein the scraped surface heat exchanger is operated with a speed of the shaft of less than 800 RPM, preferably less than 700 RPM, more preferably less than 600 RPM and most preferably less than 500 RPM.
The scraped surface heat exchanger according to claim 1, wherein the shaft comprises at least two gap portions with an outer surface and a radius.
The scraped surface heat exchanger of claim 13, wherein the at least two gap portions are arranged symmetrical with respect to the axis of rotation.
The scraped surface heat exchanger of claim 13, wherein the shaft comprises cut-off portions each being arranged between two gap portions.
The scraped surface heat exchanger of claim 15, wherein one scraping member is arranged at one cut-off portion.
The scraped surface heat exchanger according to claim 1, wherein the at least one scraping member comprises a scraping blade, preferably made of plastic.
The scraped surface heat exchanger according to claim 1, wherein the heat exchanging wall is made of stainless steel, preferably hard chromed at its inner surface.
The scraped surface heat exchanger according to claim 1, wherein the at least one scraping member is pivotally mounted at the shaft.
The scraped surface heat exchanger according to claim 1, wherein the shaft comprises a recess preferably connected to passages for passing a cooling fluid through the recess.
The scraped surface heat exchanger according to claim 1, further comprising an outer wall defining a heat exchanger fluid room between its inner surface and the outer surface of the heat exchanging wall.
A method for producing whey protein concentrate (WPC) comprising at least the following steps:
The method according to claim 22, wherein the scraped surface heat exchanger is operated with a speed of the shaft of less than 900 RPM.
The method according to claim 22, wherein the shear rate exerted by the scraping member on the whey protein material is less than 500/s, preferably less than 400/s, more preferably less than 350/s and most preferably less than 300/s.
The method according to claim 22, wherein the scraped surface heat exchanger is operated with a speed of the shaft of less than 800 RPM, preferably less than 700 RPM, more preferably less than 600 RPM and most preferably less than 500 RPM.
The method according to claim 22, wherein the generated whey protein concentrate has an average particle size of less than 6 μm.
The method according to claim 22, wherein the generated whey protein concentrate has an average particle size of greater than 2 μm.
The method according to claim 22, wherein the generated whey protein concentrate has an average particle size of greater than 3 μm.
The method according to claim 22, wherein the generated whey protein concentrate has an protein content from 30 to 90% of the dry matter.
The method according to claim 22, wherein the generated whey protein concentrate has a protein content from 50 to 80% of the dry matter.
The method according to claim 22, wherein the generated whey protein concentrate has a dry matter content greater than 10%.
The method according to claim 22, wherein at least two and preferably all of the steps (a) and (b) and (c) are carried out in the same scraped surface heat exchanger.
The method according to claim 22, wherein at least two and preferably all of the steps (a) and (b) and (c) are carried out in a plurality of scraped surface heat exchangers.
The method according to claim 22, wherein the whey protein material is preheated in a tubular heat exchanger before step (a).
The method according to claim 22, wherein the whey protein material is cooled in a tubular heat exchanger after step (c).
Dependencies are inferred from the claim text.