Membrane apparatus having alternate opposite flow transverse to means flow

DETAILED DESCRIPTION We claim: 1.
Apparatus for effecting transfer of heat or mass between two fluids through a transfer membrane, comprising a first conduit having generally opposite edges for the flow of a first one of the fluids and defined between two predomiantly planar surfaces of which at least one is provided by the membrane, said membrane having alternate furrows and ridges extending side-by-side in a direction with a component along the first conduit, said first conduit having a longitudinal direction extending generall in the direction of said flow; first pumping means for passing the first fluid with a mean flow along the first conduit, and second pumping means for applying fluid pressure alternately to generally opposite edges of said first conduit to superimpose on the mean flow a reciprocatory flow component transverse to the direction of mean flow and transverse to the length of the furrows and ridges to cause a resulting pulsation of fluid to translate the fluid first in one direction and then in an opposed direction past the furrows to produce in the furrows a rotary flow having components of motion parallel and perpendicular to the reciprocatory flow component and to the membrane.
2.
Apparatus according to claim 1, in which the conduit has opposite side edges and the second pumping means comprises a flexible bladder (16) along each side edge of the conduit, and means (27, 30) for activating the two bladders in turn to apply pressure alternately to said opposite side edges of the conduit.
3.
Apparatus according to claim 2, in which each bladder is subdivided (33) in the longitudinal direction of the conduit so that each part of the bladder (16) pumps fluid back into only an adjacent part of the conduit.
4.
Apparatus according to claim 1, in which the first pumping means comprises a roller pump (21).
5.
Apparatus according to claim 1, in which the furrows (39) extend substantially parallel to the longitudinal direction of the conduit.
6.
Apparatus according to claim 1, in which the furrows (38) extned obliquely to the longitudinal direction of the conduit