# US 4,392,526 A · Concentric tube heat exchanger with spacer

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- Number: US 4,392,526 A
- Document ID: US4392526A
- Status: Granted
- Kind: A
- Application number: 06/257,085
- Filed: 1981-04-24
- Granted: 1983-07-12
- Earliest claimed: 1980-05-08
- Assignees: Wieland-Werke AG
- Inventors: Manfred Hage; Hans Demuth; Otto Junker
- Web page: https://patentgrep.com/patent/US4392526A

## CPC

- F28F 9/013: for tubes or tube-assemblies
- F16L 7/00: Supporting pipes or cables inside other pipes or sleeves, e.g. for enabling pipes or cables to be inserted or withdrawn from under roads or railways without interruption of traffic (sleeves for supporting pipes, cables or protective tubing, between relatively movable points F16L3/01)
- F28D 7/106: {consisting of two coaxial conduits or modules of two coaxial conduits}
- F28F 2240/00: Spacing means
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)

## Abstract

A heat exchanger for transferring heat from liquids or gases has an outer tube spaced from an concentric finned inner tube by a plurality of spacers. The spacers each have a tubular sleeve which engages the fins of the inner tube and a portion of the sleeve engages in the groove between adjacent fin turns of the inner tube. The outer surface of the spacer engages the internal surface of the outer tube. The spacer is preferably made of plastics material and the inner finned tube has fins formed in a threaded fashion. A preferred embodiment of the heat exchanger has a longitudinally slotted sleeve and the adjacent edges of the slot are formed to provide a snap-in engagement.

## Claims

### Claim 1

A heat exchanger comprising an outer tube, at least one substantially concentric inner tube having an outer surface, a fin radially extending from the outer surface of the inner tube and having a height less than the distance between the inner and outer tubes, said fin being formed around the inner tube and extending therealong in turns, spacers being provided between each of the tubes, each spacer having a tubular sleeve which bears against the outer surface fin of the inner tube and at least three circumferentially, substantially equi-spaced, radial supporting elements supporting the outer tube inner wall, said tubular sleeve having at least one retaining member engaging in the groove between adjacent fin turns.

### Claim 2 (depends on 1)

A heat exchanger according to claim 1, wherein said retaining member is in the form of at least one resilient retaining lug.

### Claim 3 (depends on 1)

A heat exchanger according to claim 1, wherein the fin turns are in the form of an external thread on the inner tube and the tubular sleeve has an internal thread conforming to said fin turns.

### Claim 4 (depends on 3)

A heat exchanger according to claim 3, wherein the internal thread consists of one thread turn.

### Claim 5 (depends on 4)

A heat exchanger according to claim 4, wherein the internal thread consists of a broken thread turn.

### Claim 6 (depends on 3)

A heat exchanger according to claim 3, wherein the spacer is in the form of extruded section.

### Claim 7 (depends on 1)

A heat exchanger according to claim 1, wherein the spacer is made of plastics material.

### Claim 8 (depends on 7)

A heat exchanger according to claim 7, wherein the tubular sleeve is provided with a longitudinal slot.

### Claim 9 (depends on 8)

A heat exchanger according to claim 8, wherein adjacent longitudinal edges of the slot are arranged for snap-in engagement.

### Claim 10 (depends on 7)

A heat exchanger according to claim 7, wherein the spacer is in two parts and is connected via supporting elements which are curved toward the outer tube.