GB2303438A

GB2303438A - Vehicle heat exchanger vent arrangement

Info

Publication number: GB2303438A
Application number: GB9514719A
Authority: GB
Inventors: Graham Gerald Lardner
Original assignee: Llanelli Radiators Ltd
Current assignee: Marelli Automotive Systems UK Ltd
Priority date: 1995-07-19
Filing date: 1995-07-19
Publication date: 1997-02-19
Also published as: GB9514719D0

Description

Vehicle Heat Exchanger The present invention relates to a vehicle heat exchanger.

Known vehicle heat exchangers (such as radiators) often utilise a flexible vent pipe connected at the top of the inlet header tank to vent trapped air and overflow fluid coolant to a partial flow tank. The partial flow tank separates the air (which is vented to atmosphere) and overflow coolant (which is directed to rejoin the vehicle cooling circuit downstream of the radiator).

Problems exist with known vent pipes because they tend to occupy excess space in the engine bay of the vehicle (such space being at a premium), because the hot overflow coolant tends to degrade the vent pipe, and because leaks may occur particularly at vent pipe connections.

An improved heat exchanger has now been devised.

According to the present invention, there is provided a vehicle heat exchanger comprising: (a) spaced header tanks; (b) an array of substantially parallel conduits at least some of which communicate between the spaced header tanks thereby providing a heat exchange core permitting heat exchange fluid to communicate between the header tanks through the core; and (c) vent conduit means connected to one of the header tanks and arranged to vent air and overflow heat exchange fluid away from the header tank; wherein, the vent conduit means comprises one of the conduits in the array.

The invention thereby effectively replaces the separate vent pipe of prior art constructions with a conduit of the array.

Therefore, it is preferred that the vent conduit means and one or more (preferably all) other conduits comprising the array comprise metallic tubes, preferably comprising aluminium or aluminium alloy.

It follows that it is preferred that the vent conduit means and one or more other conduits comprising the array are of substantially uniform shape and dimensions.

Furthermore, the spacing between adjacent conduits in the array is preferably substantially uniform, the spacing between the vent conduit means and an adjacent conduit conforming to the substantially uniform spacing of conduits comprising the remainder of the array.

Desirably, the vent conduit means comprises a vent flowpath extending from said one header tank, the vent flowpath further comprising a portion (preferably a chamber or duct portion) at least partially defined by a wall of the other header tank.

The vent conduit means preferably comprises the uppermost conduit of the array, the vent conduit means preferably being communicatively connected to the inlet header tank of the heat exchanger.

Advantageously, the vent conduit means comprises a vent flowpath extending to separator means, the separator means preferably comprising a tank mounted to, or formed to be integral with a header tank.

The invention will now be further described in specific embodiments, by way of example only, and with reference to the accompanying drawings, in which; Figure 1 is a schematic representation of a prior art vehicle heat exchanger; Figure 2 is a schematic representation of a first embodiment of vehicle heat exchanger according to the present invention; and Figure 3 is a schematic representation of an alternative embodiment of heat exchanger in accordance with the invention.

Referring to the drawings, and initially to Figure 1, there is shown a prior art vehicle radiator 1, comprising an inlet header tank 2, and outlet header tank 3 and an intermediate radiator core assembly 31.

Radiator core assembly 31 is of substantially conventional construction comprising a series of spaced substantially parallel metallic tubes 4 (typically of aluminium or aluminium alloy) extending between header tanks 2,3. The core 31 typically extends for substantially the entire depth of the radiator 1, however only the uppermost four tubes 4 are shown in the drawings for the purpose of clarity of explanation.

Intermediate adjacent tubes 4 are positioned in conventional manner, metallic concertina strips 33 to provide an airflow matrix through the radiator in the direction of the plane of the paper in the drawings. The radiator operates in a conventional manner whereby relatively higher temperature fluid coolant (typically water) is supplied via inlet header tank 2, the fluid passing along tubes 4 where heat is exchanged between the metallic concertina strips 33 (which are in thermally conductive contact with tubes 4) and forced air so as to cool the fluid coolant in tubes 4. The fluid coolant then passes on into the hose portion 35 of the vehicle coolant circuit downstream of the radiator via outlet header tank 3.

Often, air bubbles evolve in the fluid coolant in the radiator, and air tends to collect towards the top of the inlet header tank 2. Conventionally, as shown in Figure 1, a flexible vent pipe 5 is connected at the top of inlet header tank 2 and extends to a partial flow tank 6 positioned adjacent outlet header tank 3 on the other side of the radiator. Trapped air collected at the top of inlet header tank 2 is forced, together with overflow fluid coolant, along vent pipe 5 to partial flow tank 6 where the air is permitted to vent to atmosphere through vent 7, the overflow fluid coolant being returned to the mainvehicle coolant circuit via connecting conduit 8.

Referring to Figure 2, a radiator 10 according to the invention generally conforms to the construction described in relation to Figure 1 having inlet header tank 12, outlet header tank 13 and an array of transversely extending tubes 14. Tubes 14 are prefabricated as an array prior to being joined to header tanks 12,13. Typically, the tubes are of aluminium or aluminium alloy (as are the concertina strips 33), the array being brazed together in a conventional manner. In this embodiment however, vent pipe 5 is effectively replaced by the uppermost transversely extending tube 14a of the array, which communicates at one end with the interior of inlet header tank 12 and at its other end with a small cylindrical chamber 11 formed by a wall 19 which effectively closes the top of outlet header tank 13.A short extension pipe 15 connects chamber 11 with partial flow tank 16 to complete the vent flowpath between inlet header tank 12 and partial flow tank 16.

Because the separate, flexible vent pipe 5 has effectively been dispensed with, the space available in the vehicle engine bay is increased. Furthermore, because tube 14a is effectively the uppermost tube of a standard aluminium brazed radiator core problems associated with thermal degradation of the flexible vent pipe 5 and leakage at connection points are effectively ameliorated.

Referring to Figure 3, an alternative embodiment of radiator 20 is generally of a similar construction to that described in relation to Figure 2. In this embodiment however chamber 11 is replaced with a duct 21 extending downwardly on the outside of outlet header tank 23. Mating ports provided for the outlet header tank 23 and partial flow tank 26 enable the partial flow tank to be mounted on, and supported by header 23.

Alternatively, partial flow tank 26 may be formed to be integral with outlet header tank 23 for example by brazing. Duct 21 is formed to be integral with outlet header tank 23 by providing an internal separating wall 29 in a tubular casing 30 which is closed at opposed ends.

Claims

Claims:

1. A vehicle heat exchanger comprising: a) spaced header tanks; b) an array of substantially parallel conduits at least some of which communicate between the spaced header tanks thereby providing a heat exchange core permitting heat exchange fluid to communicate between the header tanks through the core; and c)vent conduit means connected to one of the header tanks and arranged to vent air and overflow heat exchange fluid away from the header tank; wherein, the vent conduit means comprises one of the conduits in the array.

2. A vehicle heat exchanger according to claim 1, wherein the vent conduit and one or more other conduits comprising the array comprise metallic tubes.

3. A vehicle heat exchanger according to claim 2, wherein the vent conduit and substantially all other conduits comprising the array comprise metallic tubes.

4. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means comprises an aluminium or aluminium alloy tube.

5. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means and one or more other conduits comprising the array are of subtantially uniform shape and dimensions.

6. A vehicle heat exchanger according to claim 5, wherein the vent conduit means and substantially all other conduits comprising the array are of subtantially uniform shape and dimensions.

7. A vehicle heat exchanger according to any preceding claim, wherein the spacing between adjacent conduits in the array is substantially uniform, the spacing between the vent conduit means and an adjacent conduit conforming to the substantially uniform spacing of conduits comprising the remainder of the array.

8. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means comprises a vent flowpath extending from said one header tank, the vent flowpath further comprising a portion at least partially defined by a wall of the other header tank.

9. A vehicle heat exchanger according to claim 8, wherein the portion of the flowpath at least partially defined by the wall of the header tank comprises a chamber or duct formed to be integral with the wall of the header tank.

10. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means comprises the uppermost conduit of the array.

11. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means is comunicatively connected to the inlet header tank of the heat exchanger.

12. A vehicle heat exchanger according to any preceding claim, wherein the vent conduit means comprises a vent flowpath extending to separator means.

13. A vehicle heat exchanger according to claim 12, wherein the separator means comprises a tank mounted to, or formed to be integral with a header tank.

14. A vehicle heat exchanger substantially as herein described with reference to figures 2 and 3 of the accompanying drawings.