Hollow fiber membrane module for use in a tubular pressure vessel
View Patent ↗A hollow fiber membrane element may be used in a pressure vessel similar to those used with spiral wound elements, optionally as a replacement for a spiral wound element. A connecting sleeve is used to connect the insides of adjacent elements to each other or to one or more fittings in communication with the outside of the pressure vessel. The element has hollow fiber membranes suspended between two potting heads spaced apart by a cross flow tube that is open at the outside faces of both potting heads. The potting heads are each adapted to slide into an end of a connecting sleeve. A module has one or more hollow fiber elements located inside of a pressure vessel. At least one port is provided in communication between the outsides of the one or more elements and the outside of the vessel. An aerator may be provided on the bottom of the vessel. In an outside-in flow process, feed water enters through the port and flows to the outside of one or more elements while permeate is removed through a fitting at one or both ends of the module. In an inside-out process, feed water enters through a fitting and permeate is removed through a port.
1. A hollow fiber membrane module comprising,
a) a generally tubular pressure vessel;
b) at least two hollow fiber elements located inside of the vessel, each of the hollow fiber elements having a pair of opposed potting heads with a plurality of hollow fiber membranes extending between the potting heads, the ends of the hollow fiber membranes being open to an outer face of at least one of the potting heads, the element having at least one cross flow tube for fluid flow from the outer face of one of the potting heads to the outer face of the other potting head; and
c) a connector located inside of the vessel between the at least two hollow fiber elements, the connector having a tubular body spaced from the inside of the pressure vessel by a gap;
d) a port into the vessel adapted to provided fluid communication between the outside of the vessel and the outer surfaces of the membranes;
e) an opening into the vessel adapted to permit communication between the outside of the vessel and the lumens of the membranes; and,
f) an aerator at the bottom of the tubular pressure vessel, wherein an inlet of the aerator is located in the gap below the body of the connector, and the module comprises an air inlet adapted to permit compressed air to be discharged into the gap near the inlet of the aerator,
wherein
g) each of the at least two hollow fiber elements has one of its potting heads sealed to the inside of the tubular body of the connector such that the ends of the hollow fiber membranes of one of the hollow fiber elements are in fluid communication with the cross flow tube of the other hollow fiber element through the connector.
2. The module of claim 1 wherein the connector has spacers extending from the outside of the tubular body of the connector to the inner surface of the pressure vessel, the spacers passing through the gap but not preventing fluid flow through the gap.
3. The module of claim 2 wherein the connector has a separator extending inwards from the connector between the potting heads of the at least two hollow fiber elements.
4. The module of claim 1 wherein each of the hollow fiber elements comprises a cross flow tube open to the outer face of each of the potting heads.
5. The module of claim 4 wherein the membranes have an outside diameter of 2 mm or less or 1 mm or less.
6. The module of claim 5 wherein the length of each of the two or more elements is 1016 mm or less between the outer faces of the potting heads.
7. The module of claim 6 wherein the wherein the length of each of the two or more elements is 508 mm or less between the outer faces of the potting heads.
8. The module of claim 1 further comprising a second connector, wherein one of the at least two hollow fiber elements has one of its potting heads sealed to the inside of the second connector.
9. The module of claim 8 further comprising a fitting, the fitting being sealed to the inside of the second connector and extending through the opening, wherein communication between the outside of the vessel and the lumens of the membranes is provided through the fitting.
10. The module of claim 1 wherein the aerator receives air from an inlet at one end of the aerator and discharges bubbles from openings distributed along the length of the aerator.
11. The module of claim 1 wherein the connector comprises longitudinal ribs extending across the gap on both sides of the inlet of the aerator.
12. The module of claim 1 wherein the potting heads each have at least one grooves and an O-ring installed in the groove such that the O-ring provides a seal between the outer diameter of a potting head and the inside diameter of the connector.