US4391675A — Sieve plates and distillation columns

Claim 1

Independent Claim 118 words

A sieve plate of polymeric material for use in a distillation column, characterised in that said plate comprises: (a) a circular base portion provided with (i) a central axial aperture adapted to receive a shaft, (ii) an additional aperture capable of receiving a tubular member, and (iii) a plurality of perforations such that the perforations represent in total a free area of between 3 and 20%, the perforations having a uniform average diameter between 0.6 and 4.0 mm, (b) a flexible, flared-lip portion around the circumference of the base portion providing sealing contact with the inner walls of a column and providing a reservoir for downcoming liquid, and (c) means for retaining the sieve plate on a shaft.

Claim 2

Dependent Claim 118 words

A sieve plate of polymeric material for use in a distillation column, characterised in that said plate comprises: (a) a circular base portion provided with (i) a central axial aperture adapted to receive a shaft, (ii) an additional aperture capable of receiving a tubular member, and (iii) a plurality of perforations such that the perforations represent in total a free area of between 3 and 20%, the perforations having a uniform average diameter between 0.6 and 4.0 mm, (b) a flexible, flared-lip portion around the circumference of the base portion providing sealing contact with the inner walls of a column and providing a reservoir for downcoming liquid, and (c) means for retaining the sieve plate on a shaft.

Claim 3

Dependent Claim 27 words

A sieve plate according to claim 1 wherein the perforations are distributed in such a manner that a small segment of the base portion is left unperforated.

Claim 4

Dependent Claim 149 words

A distillation column which is provided with a plurality of spaced sieve plates, characterised in that the sieve plates are of polymeric material and are mounted on a central shaft coaxial with the column, said sieve plate comprising: (a) a circular base portion provided with (i) a central axial aperture adapted to receive the shaft, (ii) an additional aperture spaced from the central aperture and capable of receiving a tubular member acting as a weir and a downcomer, and (iii) a plurality of perforations such that the perforations represent in total a free area of between 3 and 20%, the perforations having a uniform average diameter between 0.6 and 4.0 mm, (b) a flexible, flared-lip portion around the circumference of the base providing sealing contact with the inner walls of the column and providing a reservoir for downcoming liquid, and (c) means for retaining the plate on the shaft.

Claim 5

Dependent Claim 149 words

A distillation column which is provided with a plurality of spaced sieve plates, characterised in that the sieve plates are of polymeric material and are mounted on a central shaft coaxial with the column, said sieve plate comprising: (a) a circular base portion provided with (i) a central axial aperture adapted to receive the shaft, (ii) an additional aperture spaced from the central aperture and capable of receiving a tubular member acting as a weir and a downcomer, and (iii) a plurality of perforations such that the perforations represent in total a free area of between 3 and 20%, the perforations having a uniform average diameter between 0.6 and 4.0 mm, (b) a flexible, flared-lip portion around the circumference of the base providing sealing contact with the inner walls of the column and providing a reservoir for downcoming liquid, and (c) means for retaining the plate on the shaft.

Claim 6

Dependent Claim 26 words

A distillation column according to claim 3 wherein the tubular member is constructed of a different material to that of which the sieve plate is made.

Claim 7

Dependent Claim 65 words

A distillation column according to claim 3 or 4 wherein the means for retaining the sieve-plate on the shaft is a combination of a coaxial boss with a pair of opposing holes on the plates and correspondingly aligned holes on the shaft enabling a cross-pin or lock-pin to be inserted through the holes in the boss and the shaft to retain the plate in position.

Claim 8

Dependent Claim 23 words

A distillation column according to claim 5 wherein the boss is on the side of the plate opposite that bearing the lip portion.

Claim 9

Dependent Claim 38 words

A distillation column according to claim 3 or 4 wherein the shaft and the axial aperture in the plate have between them a combination of an annular slot and a flange which mate to form the retaining means.

Claim 10

Dependent Claim 25 words

A distillation column according to claim 7 wherein the flange is either an O-ring or an integral projection on the appropriate shaft or plate aperture.

Claim 11

Dependent Claim 51 words

A distillation column according to claims 3 or 4 wherein the shaft is provided along its length with a series of means for the purpose of mounting several sieve plates on the shaft said means being adapted to adjust the spacing between the plates and/or the weir height and downcomer length.

Claim 12

Dependent Claim 34 words

A distillation column as claimed in claim 3, wherein adjacent sieve plates are arranged so that the liquid descending from the plate immediately above is directed to an unperforated area of the plate below.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-07-04	1987-01-03	1987-07-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-07-04	1991-01-03	1991-07-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-07-04	1995-01-03	1995-07-05	$7700.00	Window Closed / Lapsed

Sieve plates and distillation columns

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