Non-braided, textile-reinforced hollow fiber membrane
Various methods of making a reinforced membrane, devices for making the membranes, and the resulting membranes are described. The methods typically provide a reinforcing structure that includes filaments extending around the circumference of the membrane but without the filaments being part of a braided or woven structure. Some of the reinforcing structures also include longitudinal filaments. The methods and devices can be used to make a supporting structure in line with membrane formation steps, and also allow for a reinforced membrane to be produced that has a ratio of inside-to-outside diameters of 0.5 or more.
1. An apparatus for making a hollow fiber membrane comprising,
a mandrel;
a creel at one end of the mandrel positioned to distribute a plurality of yarns around the outer surface of the mandrel;
a membrane dope coating head at another end of the mandrel; and,
one or more of a staple fiber wrapping device, a bonding device and a smoothing device located around the mandrel between the creel and the membrane dope coating head.
2. The apparatus of claim 1 , wherein the apparatus includes a stable fiber wrapping device.
3. The apparatus of claim 1 , wherein the apparatus includes a smoothing device.
4. An apparatus for making a hollow fiber membrane comprising,
a mandrel;
a source of filaments adapted to form an arrangement of filaments around the mandrel; and,
a coating head adapted to receive the plurality of filaments and apply a membrane dope to the filaments;
wherein the mandrel extends into a coating head button of the coating head such that, when the membrane dope is applied by the coating head, the membrane dope fills a gap between the mandrel and the coating head button to impregnate the plurality of filaments received in the coating head.
5. The apparatus of claim 4 wherein the mandrel has a central bore through which either a fluid or a hollow fiber may be passed.
6. The apparatus of claim 4 wherein the mandrel has at least two outer diameters at different positions along the length of the mandrel.