Makeup
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3M uses two core make-up technologies for the three-dimensional arrangement of the capillary membranes in the final device.
- P.E.T. - Performance Enhancing Technology
- Double-layer cross-wound mat
The configuration is decisive to the performance that is achievable with membranes incorporated in our customers' modules.
P.E.T.™
P.E.T.™ ensures optimum distribution of the flow around capillaries to guarantee ideal transport and removal.
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Standard capillary bundles often suffer uneven flow distribution around the capillaries: Some groups of capillaries form strains and as a consequence there are areas of stagnant flow within and shunt-flows around the strains. This results in loss of active outer capillary surface and thus loss of performance. For a dialyser, poor bundle architecture will result in poor dialysate distribution and thus loss of clearance of toxins.
Therefore 3M developed Performance Enhancing Technology – P.E.T. After the undulation of capillary membranes Poly-Ethylene-Terephthalate-spacer yarns consisting of multifilament threads are integrated into the fibre bundle.
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The type of multifilament spacer yarn, the ratio of spacer yarns and capillaries as well as the kind of entangling the yarns into the bundle are optimised to achieve the best possible performance.
P.E.T is used for both medical and industrial capillary bundles.
Characteristics of P.E.T.™
- Improves dialysate distribution throughout the dialyzer
- Increases clearance values
- Maintains consistent performance
- throughout the entire treatment
- from dialyser to dialyser
Double-Layer Cross-Wound Mat
The unique double layer cross-wound mat guarantees optimum arrangement of the capillaries. Thus ideal flow conditions around the capillaries are achieved, which is a prerequisite for top performance.
This mat can quickly, economically and easily be turned into a module by rolling it on a core and fitting it into the housing. The technically demanding processing step of winding individual capillaries to a bundle can thus be avoided.
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For the production of the cross-wound mat, capillaries are knitted to a mat of membranes with polyester warp threads. The width of the mat depends on the individual demands of the customer. Two mats are then angled and wound on a bobbin, such that the capillaries of two adjacent layers lie X-shaped on top of each other.
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Characteristics of the cross-wound mat
- Uniform distribution of capillaries
- Capillaries fixed by warp threads (no movement)
- Adaptable for various oxygenator designs (axial-, tangential-, cross-flow etc.)
- Blood-film thickness (pressure drop) can be adjusted easily
- Closed capillary ends for safe and easy potting
