Apparatus and process for membrane filtration

Claim 3

The apparatus as claimed in claim 1, wherein the support members are circular-cylindrical discs.

Claim 4

The apparatus as claimed in claim 2, wherein the disc-shaped support members are arranged with their axes co-linear to form a substantially circular-cylindrical assembly.

Claim 5

The apparatus as claimed in claim 2, wherein the inlet means is tangential to the first support member and the outlet means for concentrate is tangential to the last support member.

Claim 6

The apparatus as claimed in claim 1, wherein said permeate withdrawal means of each support member is at or near the periphery of the support member.

Claim 7

The apparatus as claimed in claim 1, further comprising a housing of liquid-impermeable material surrounding the series of support members.

Claim 8

The apparatus as claimed in claim 6, wherein the housing includes means for withdrawing permeate.

Claim 9

The apparatus as claimed in claim 1, further comprising at least one collecting vessel for receiving permeate.

Claim 10

The apparatus as claimed in claim 1, further comprising frames of rigid liquid-impermeable material covering the circumferential portion of the support members and reinforcing the support members in their peripheral regions.

Claim 11

The apparatus as claimed in claim 9, wherein each frame includes an outlet for permeate.

Claim 12

The apparatus as claimed in claim 9, wherein the frames are of metal.

Claim 13

The apparatus as claimed in claim 9, wherein the radial cross-section of each frame is L-shaped or U-shaped.

Claim 14

The apparatus as claimed in claim 9, wherein said flow provision means comprises liquid-impermeable peripheral sealing means between each two adjacent support members to prevent passage of liquid from one side of a support member to the other around its periphery.

Claim 15

The apparatus as claimed in claim 13, wherein said sealing means comprises an annular projection on a non-circumferential part of the frame mating with a complementary annular recess on the frame of an adjacent support member.

Claim 16

The apparatus as claimed in claim 13, wherein said sealing means comprises an annular recess on a non-circumferential part of the frame on each side of the support member adapted to accommodate a sealing ring.

Claim 17

The apparatus as claimed in claim 15, wherein the recesses are shaped so as to accommodate a sealing ring of circular cross-section.

Claim 18

The apparatus as claimed in claim 13, wherein said sealing means comprises on each support member on each side near its circumferential edge an annular recess adapted to accommodate a sealing ring.

Claim 19

The apparatus as claimed in claim 17, wherein the recesses are shaped so as to accommodate a sealing ring of circular cross-section.

Claim 20

The apparatus as claimed in claim 1, wherein the passageways are of circular cross-section.

Claim 21

The apparatus as claimed in claim 1, wherein the passageways are of triangular cross-section.

Claim 22

The apparatus as claimed in claim 1, wherein the passageways are of quadrilateral cross-section.

Claim 23

The apparatus as claimed in claim 1, wherein the passageways are of hexagonal cross-section.

Claim 24

The apparatus as claimed in claim 1, wherein the hydraulic diameter of each passageway is within the range of from about 0.1 to 10 mm.

Claim 25

The apparatus as claimed in claim 23, wherein the hydraulic diameter is within the range of from about 0.5 to 5 mm.

Claim 26

The apparatus as claimed in claim 24, wherein the hydraulic diameter is within the range of from about 2 to 3 mm.

Claim 27

The apparatus as claimed in claim 1, wherein the distance between adjacent support members is within the range of from about 0.1 to 10 mm.

Claim 28

The apparatus as claimed in claim 26, wherein the distance between adjacent support members is within the range of from about 0.5 to 5 mm.

Claim 29

The apparatus as claimed in claim 27, wherein the distance between adjacent support members is within the range of from about 2 to 3 mm.

Claim 30

The apparatus as claimed in claim 1, wherein the distance between adjacent support is substantially equal to the hydraulic diameter of the passageways.

Claim 31

The apparatus as claimed in claim 1, wherein the length of the flow path of the passages is from about 1 to 10 times the hydraulic diameter.

Claim 32

The apparatus as claimed in claim 30, wherein the length of the flow path of the passages is from about 4 to 6 times the hydraulic diameter.

Claim 33

The apparatus as claimed in claim 1, further comprising a first means for regulating liquid flow positioned between the inlet means and the first support member and a second means for regulating liquid flow positioned between the last support member and the outlet means for concentrate.

Claim 34

The apparatus as claimed in claim 32, wherein the means for regulating flow comprises a perforated metal sheet or a wire mesh.

Claim 35

The apparatus as claimed in claim 1, further comprising two pressure plates connected by tie rods holding the assembly of support members therebetween.

Claim 36

The apparatus as claimed in claim 34, wherein the inlet means comprises part of one pressure plate and the outlet means for concentrate comprises part of the other.

Claim 37

The apparatus as claimed in claim 1, which includes at least one means positioned between the inlet and the first support member for effecting spiral flow of the incoming liquid.

Claim 38

The apparatus as claimed in claim 1, wherein the porous material of the support members comprises aluminum oxide, silicon nitride, graphite or silicon carbide.

Claim 39

The apparatus as claimed in claim 1, wherein the porous material of the support means comprises a powder sintered metal.

Claim 40

The apparatus as claimed in claim 38, wherein the metal is bronze or chromium steel.

Claim 41

The apparatus as claimed in claim 1, wherein the porous material of the support members comprises a felt of synthetic fibers filled with synthetic resin.

Claim 42

The apparatus as claimed in claim 40, wherein the felt further comprises a metal sheet reinforcing member.

Claim 43

The apparatus as defined in claim 1, comprising a large number of said support members arranged in series.

Claim 44

A process for the membrane filtration of a liquid, comprising the steps of causing a liquid to flow through an assembly comprising at least two disc-shaped support members of porous material arranged in series and including an open space axially therebetween, each support member having a diameter which is large in relation to its thickness and including a plurality of liquid flow passageways therethrough wherein the liquid flow passageways of each support member are displaced with respect to those in each adjacent support member, the liquid entering through an inlet to the first support member and flowing along a path constituted by the plurality of passageways through each support member, whereby the direction of liquid flow is caused to change in each of said spaces to achieve more effective contact with support members, every part of the surface of each support member coming into contact with the liquid being covered with a semipermeable membrane, whereby permeate gains access to the porous material of the support members, collecting the permeate from within the porous material of each support member and collecting the concentrate at an outlet from the last support member.

Claim 45

A process for the membrane filtration of a liquid, comprising the steps of causing a liquid to flow through an assembly comprising at least two disc-shaped support members of porous material arranged in series and including an open space axially therebetween, each support member having a diameter which is large in relation to its thickness and including a plurality of liquid flow passageways therethrough wherein the liquid flow passageways of each support member are displaced with respect to those in each adjacent support member, the liquid entering through an inlet to the first support member and flowing along a path constituted by the plurality of passageways through each support member, whereby the direction of liquid flow is caused to change in each of said spaces to achieve more effective contact with support members, every part of the surface of each support member coming into contact with the liquid being covered with a semipermeable membrane, whereby permeate gains access to the porous material of the support members, collecting the permeate from within the porous material of each support member and collecting the concentrate at an outlet from the last support member.

Claim 46

The process as claimed in claim 43, said process being carried out using apparatus as claimed in claim 1.