Compressed air dryer

Claim 1

In a compressed air dryer of the type wherein hot moist air flows from a compressor through an air- to-air heat exchanger to an air-to-refrigerant heat exchanger and then back through the air-to-air heat exchanger to dehumidify the air, the improvement wherein each of said heat exchangers comprises a sealed shell formed of substantially identical half-sections joined along their longitudinal edges having therein respective tube bundles, said tube bundles comprising a plurality of closely spaced parallel extending sheet metal fins having holes therein through which the tubes extend longitudinally within said shells, said air-to-air heat exchanger having sealed end chambers at opposite ends thereof into which the tubes of the corresponding tube bundle open, an intermediate chamber provided with an entrance port at one end by which moist compressed air is supplied thereto and an exit port adjacent the opposite end via which the air leaves said intermediate chamber, and baffles on the interior of said shell half- sections for directing the flow of air therethrough in a plurality of oppositely directed passes, said air-to-refrigerant heat exchanger having an entrance port adjacent one end that is connected to the exit port of the air-to-air heat exchanger and an exit port adjacent the opposite end that is connected to one of the sealed end chambers of the air-to-air heat exchanger, and baffles on the interior of said shell half-sections for directing the flow of air in a plurality of oppositely directed passes over the tube bundle of said air- to-refrigerant exchanger, the air from the air-to-refrigerant heat exchanger flowing via the said one sealed end chamber through the tubes of the tube bundle of said air-to-air heat exchanger and exiting via the opposite one of said sealed end chambers, condensed moisture which collects on the fins of said tube bundles falling by gravity to the bottom of said shells, and drainpipe means for draining the moisture from said shells.

Claim 4

The method of operating a compressed air dryer of the type wherein hot moist gas from a compressor flows through an air-to-air heat exchanger to an air-to-refrigerant exchanger and then back through the air-to-air heat exchanger to dehumidfy the air, wherein the improvement comprises flowing the hot moist gas progressively in a series of oppositely directed passes between groups of closely spaced corrugated sheet metal fin elements forming part of the tube bundles in the air-to-air exchanger and then in a series of oppositely directed pases between groups of closely spaced corrugated sheet metal fin elements forming part of the refrigerating tube bundles of said air-to-refrigerant exchanger to capture oil and solid particles and so that the water condensing thereon washes the fin elements, the water collecting on said sheet metal fin elements obviating separators or absorbent material for removing water from the outflow of air from said first heat exchanger.

Claim 5

The method of operating a compressed air dryer of the type wherein hot moist gas from a compressor flows through an air-to-air heat exchanger to an air-to-refrigerant exchanger and then back through the air-to-air heat exchanger to dehumidfy the air, wherein the improvement comprises flowing the hot moist gas progressively in a series of oppositely directed passes between groups of closely spaced corrugated sheet metal fin elements forming part of the tube bundles in the air-to-air exchanger and then in a series of oppositely directed pases between groups of closely spaced corrugated sheet metal fin elements forming part of the refrigerating tube bundles of said air-to-refrigerant exchanger to capture oil and solid particles and so that the water condensing thereon washes the fin elements, the water collecting on said sheet metal fin elements obviating separators or absorbent material for removing water from the outflow of air from said first heat exchanger.