Liquid purification or separation – Casing divided by membrane into sections having inlet – Energy recovery from treated liquid
Patent
1980-06-12
1982-11-02
Spear, Jr., Frank A.
Liquid purification or separation
Casing divided by membrane into sections having inlet
Energy recovery from treated liquid
210356, 422 48, B01D 3100
Patent
active
043572391
DESCRIPTION:
BRIEF SUMMARY
The invention is concerned with apparatus for effecting transfer of heat or mass between two fluids of which at least one is usually a liquid, through a transfer membrane. Such apparatus is used in blood oxygenators, that is artificial lungs, and dialysers, such as artificial kidneys, in which case one fluid is blood, and the other is oxygen or dialysate. In practice the efficiency of the transfer across the membrane is limited by the extent to which the total volume of fluid can be brought into close proximity with the membrane. It is not sufficient to reduce the thickness of the fluid layers, by reducing the thickness of the conduits in which they flow, as this increases undesirably the pressure drop across the apparatus and leads to uneven perfusion and regions of stagnation, which, in the case of blood, provides a danger of thrombosis.
We believe that the proper solution lies in so shaping the fluid flow conduits that significant mixing of the fluid occurs within the conduits. It has previously been proposed in British Patent Specification No. 1,442,754 to provide an apparatus comprising a conduit for flow of one of the fluids at least partially defined by the membrane, a transverse dimension of the conduit varying, either inherently or in response to pressure of fluid therein, in a regularly repeating manner, to provide a multiplicity of hollows in the membrane, the apparatus also comprising means communicating with the conduit for passing fluid through the conduit in pulsatile flow, the arrangement being such that pulsation of fluid past the hollows gives rise in the hollows to rotational fluid flow having components of motion parallel and perpendicular to the general direction of flow in the conduit of the fluid.
The conduit may be defined between two predominantly planar surfaces, so that it has an elongate cross section transverse to the general direction of mean flow through the conduit, at least one of the surfaces then being provided by the membrane in which the requisite hollows are provided by parallel furrows. Alternatively, the conduit may be tubular, that is essentially axisymmetric with its wall provided by a membrane and having alternate annular or helical hollows and ridges. In either case, it has previously been proposed to cause the two fluids, between which transfer is to be effected through the membrane, to flow on opposite sides of the membrane in countercurrent or crosscurrent.
While experimenting with these earlier proposals, particularly as applied to dialysers, in which both fluids are liquids, we have found that there is a likelihood of undesirable reverse ultrafiltration. This occurs when, as a result of the pulsatile flow of one or both liquids, dialysate pressure exceeds blood pressure, even transiently, and is a potential hazard to the patient.
We now find that the problem can be substantially overcome by providing pulsatile flow components in the two fluids in phase and in the same direction.
In accordance with the present invention therefore, apparatus for effecting transfer of heat or mass between two fluids through a transfer membrane comprises two conduits separated by a common wall formed by the membrane, a pumping means for pumping the two fluids with a mean countercurrent flow each through a respective one of the two conduits, and for applying to both fluids in the conduits in phase and in the same direction a superimposed pulsatile flow, a transverse dimension of a first one of the conduits varying, either inherently or in response to pressure of fluid therein, in a regularly repeating manner in the direction of the pulsatile flow component, to provide a multiplicity of hollows in the membrane such that pulsation of fluid past the hollows gives rise in the hollows to rotary flow having components of motion parallel and perpendicular to the direction of the pulsatile flow component in that conduit and to the membrane wall.
The synchronism of the pulsatile flow component of the two fluids, in the same direction on opposite sides of the transfer membrane, can be arra
REFERENCES:
patent: 3238703 (1966-03-01), Straschil et al.
patent: 3256678 (1966-06-01), Bertin et al.
patent: 3616930 (1971-11-01), Muir
patent: 3864248 (1975-02-01), Granger et al.
patent: 4075091 (1978-02-01), Bellhouse
patent: 4111659 (1978-09-01), Bowley
patent: 4173537 (1979-11-01), Newhart
patent: 4182653 (1980-01-01), Bellhouse
patent: 4222869 (1980-09-01), Kato
Bellhouse, et al., "Development of a Vortex Mixing Haemodialyser", from European Society for Artificial Organs, 11-21-78, vol. 18, 22 pp.
Bellhouse Brian J.
Haworth William S.
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