GB2310488A

GB2310488A - Heat exchange conduit

Info

Publication number: GB2310488A
Application number: GB9603573A
Authority: GB
Inventors: Allan Grimsley; Andrew Grimsley; Adrian Nicholas Troop
Original assignee: NU HEAT UK Ltd
Current assignee: NU HEAT UK Ltd
Priority date: 1996-02-20
Filing date: 1996-02-20
Publication date: 1997-08-27
Anticipated expiration: 2016-02-20
Also published as: GB2310488B; GB9603573D0

Abstract

The conduit contains two (or more) passages for conveying a heat-carrying fluid in a countercurrent flow pattern e.g. in a sub-floor heating system. An integral extrusion comprises two parallel tubes 1 and 2 joined by a short web 3. The tubes have raised platforms 4 with co-planar longitudinally extending flats 5 to provide maximum heat transfer to the surface of the floor. One of the tubes is provided with a distinguishing rib 6 to allow the respective tubes to be identified visually and by touch alone.

Description

HEAT EXCHANGE CONDUIT TECHNICAL FIELD OF THE INVENTION This invention relates to heat exchange conduit for conveying a heatcontaining fluid in a countercurrent flow pattern. The conduit can be installed in a wood or concrete floor in order to heat the floor and the space above the floor.

BACKGROUND Countercurrent suSfloor heating systems are well known, e.g. from Canadian Patent No. 552 1 79.

The present invention seeks to provide a heat exchange conduit which is patentably different from existing conduits as used in countercurrent heating systems.

SUMMARY OF THE INVENTION The present invention proposes a heat exchange conduit comprising at least two fluid-conducting passages extending longitudinally of the conduit in a parallel relationship, the external surface of the conduit being formed with a longitudinally extending substantially planar area.

In order to maximise the area available for heat transfer, the said planar area is preferably formed on an upstanding platform.

The planar area may be smooth or textured.

In a preferred form of the conduit the two passages are each defined by partcircular walls. Each of the said part-circular walls may be associated with a common planar area. Alternatively, each part-circular wall may be associated with a respective planar area. In the latter case, the planar areas are preferably substantially co-planar.

When the conduit is installed adjacent to the surface of a floor the planar area or areas promote heat transfer to the floor surface and thence to the space above the floor, resulting in improved heating efficiency.

The walls of the conduit associated with each passage preferably differ in shape to facilitate identification of the passages at each end. In a preferred embodiment which allows the flow and return passages to be easily distinguished after being installed in a floor construction, the wall associated with one of the passages is provided with an external axiallyextending rib.

The said rib is preferably disposed adjacent to the associated planar area.

BRIEF DESCRIPTION OF THE DRAWINGS The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a transverse cross section through a heat exchange conduit of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS The heat exchange conduit is a single extrusion formed from neoprene or other suitable flexible and heat-resistant thermoplastic material. The conduit is of substantially uniform transverse cross-sectional shape and comprises a pair of substantially circular tubes 1 and 2 of the same diameter. The tubes extend parallel to each other and are joined by a single short and relatively thin web 3. Each tube is formed with an external raised platform 4 which provides a longitudinally extending flat 5. Although the flats need not be formed on raised platforms the use of platforms allows the area of the flats to be maximised without reducing the wall thickness of the tubes. Both of the flats lie on a common plane which is parallel to a plane passing through the centres of the two tubes.

One of the tubes 1 is provided with a longitudinally extending external rib 6 which allows the two tubes to be distinguished both visually and by touch alone. The rib is located adjacent to the respective platform 4 on the side remote from the other tube 2.

In use, the conduit is embedded in a floor with the flats 5 disposed adjacent to the upper surface of the floor. The ends of the two tubes are connected up in known manner such that a heat-carrying fluid (usually water) flows in opposite directions through the two tubes. The identification rib 6 ensures that the two tubes are easily identified at both ends during connecting up, and the positioning of the rib ensures that it is visible from above (i.e. from the side provided with the flats 5). The flats 5 ensure maximum heat conduction to the surface of the floor, thereby improving the efficiency with which the space above the floor is heated.

Although the flats 5 are shown as being smooth and flat they may also be textured, e.g. by provision of shallow longitudinally extending grooves. Such texturing further increases the surface area adjacent to the floor surface, thereby enhancing the efficiency of heat transfer to the floor surface.

The use of two tubes joined by a thin web allows the tubes to be easily separated at each end of the conduit to facilitate their connection to manifolds or supply pipework. Improved heat transfer may however be obtained by infilling the gap between the flats 5 so that the conduit has a single flat area of increased surface area.

It will be appreciated that the conduit could comprise more than two coplanar tubes all formed with respective co-planar flats or a single common flat. In such a case the tubes will be connected so that the heating fluid passes in opposite directions through adjacent tubes. The conduit can also be installed in other substrates, e.g. a wall.

Claims

1. A heat exchange conduit comprising at least two fluidconducting passages extending longitudinally of the conduit in a parallel relationship, the external surface of the conduit being formed with a longitudinally extending substantially planar area.

2. A heat exchange conduit according to Claim 1, in which the said planar area is formed on an upstanding platform.

3. A heat exchange conduit according to Claim 1 or 2, in which said planar area is smooth.

4. A heat exchange conduit according to Claims 1 or 2, in which said planar area is textured.

5. A heat exchange conduit according to any preceding claim, in which said at least two passages are defined by respective part-circular walls.

6. A heat exchange conduit according to Claim 5, in which said part-circular walls are associated with a common planar area.

7. A heat exchange conduit according to Claim 5, in which each part-circular wall is associated with a respective planar area.

8. A heat exchange conduit according to Claim 7, in which the planar areas are substantially co-planar.

9. A heat exchange conduit accordingto Claim 5, 7 or 8, in which the or each adjacent pair of part circular walls are joined by a single short web.

10. A heat exchange conduit according to any preceding claim, in which the walls of the conduit associated with the respective passages differ in shape to facilitate identification of the passages at each end.

11. A heat exchange conduit according to Claim 10, in which the wall associated with one of the passages is provided with an external axiallyextending rib.

12. A heat exchange conduit according to Claim 11, in which the said rib is disposed adjacent to the associated planar area.

13. A heat exchange conduit having a cross-sectional shape which is substantially as shown in the accompanying drawing.