The present invention relates to a device for the optimisation of heat exchangers.

Although the following description refers to heat exchangers and in particular heat exchange systems with multi-circuit finned coil units, the person skilled in the art will appreciate that the present invention can be used with any type of heat exchanger and/or heating or cooling system, as well as single or multicircuit evaporator components. This includes single or multicircuit condensers, evaporators, heat pumps and/or the like. The person skilled in the art will also appreciate that the term fluid includes compounds in the liquid phase or state as well as the gaseous phase or state.

Presently, finned coil (also called finned tube) evaporator components in many heat exchange systems, for example fluid and liquid-vapour refrigeration systems comprise a plurality of tube circuits fitted within a finned block. Air flows through the finned block and over the tubes and is cooled by the evaporation of the fluid in the tubes . In multi-circuit vapour compression refrigeration systems the heat exchange fluid enters the evaporator component via a distributor unit. The function of the distributor unit is to supply an equal amount or quantity of fluid to each of the tubes or circuits.

However, it is an increasingly recognised problem that despite distributor units or distributor methods being used, unequal and/or maldistribution of fluid occurs . This is evidenced by unequal temperatures of airflows leaving the finned block, uneven frosting, and uneven condensate formation and flow across the face of the finned block.

Inefficient flow and/or maldistribution of fluid reduces the efficiency of the heat exchange systems and as a result the energy requirement of such systems increases, or the cooling performance achieved is sub-optimal. This problem is compounded as many heat exchange systems are on-duty continuously and therefore even small los ses in efficiency can be costly over time. It is intended that the tube circuits within the finned coil block provide the same amount of cooling.

It is an aim of the present invention to provide an apparatus that addres ses the abovementioned problems .

It is a further aim of the present invention to provide a method of using an apparatus that addres ses the abovementioned problems.

It is a yet further aim of the present invention to provide a heat exchange system that addresses the abovementioned problems .

In a first aspect of the invention there is provided an apparatus suitable for optimising fluid flow in a heat exchange system, said apparatus including at least two vane means for directing the flow of fluid through and/or over the apparatus, said vane means extending along at least part of the length of the apparatus, wherein said vane means are arranged such that at least part, or a surface, of a first vane means is substantially parallel to at least part, or a surface, of a second and/or further vane means.

Typically the vane means are any one or any combination of fins, blades, projections and/or other such surfaces. Further typically the plane formed by, and/or longitudinal axis of the surface of the first vane means is substantially parallel to the plane formed by, and/or longitudinal axis of the second and/or further vane means.

In one embodiment the apparatus includes a plurality of vane means. Typically the vane means are substantially planar.

Preferably the longitudinal axis of the vane means forms, and/or is at, an angle to the longitudinal axis of the apparatus . Typically the vane means extend helically and/or spirally around the central longitudinal axis of the apparatus. Further typically the arrangement of the vane means is such that the fluid flowing through the apparatus is directed or forced to flow in a direction at an angle to the longitudinal axis of the apparatus .

In one embodiment the fluid is directed or forced to flow in a rotational manner in respect of a longitudinal axis of the apparatus. Typically the fluid is directed or forced to flow in a vortical manner and/or in a vortex. Further typically the vane means imparts directionality to the fluid, said directionality typically at an angle to the direction of flow of the fluid before the same enters the apparatus .

In one embodiment at least one vane means is in the form of a tube or sleeve. Typically the tube or sleeve is spirally and/or helically shaped. Further typically the apparatus includes a plurality of sleeves and/or tubes, wherein at least two of the tubes or sleeves are arranged parallel to each other.

In an alternative embodiment a bundle of vane means in the form of tubes are wrapped around a body portion. Typically the tubes are twisted or coiled around the body portion. Preferably the apparatus includes a housing. Typically the housing is substantially cylindrical and/or a cylindrical tube. Further typically the vane means are located inside the housing.

In one embodiment the vane means form one or more channels and/or conduits within the housing, heat exchanger tubing and/or pipework in which the apparatus is located in use. Typically at least one wall or surface of the channels and/or conduits formed is common or shared with a wall or surface of the housing, heat exchanger tubing and/or pipework in which the vane means are located. Further typically the wall or surface of the housing, heat exchanger tubing and/or pipework which makes up at least part of the channels and/or conduits is the inner wall or surface.

In one embodiment the vane means breaks down and/or divides bubbles in the fluid flow into smaller bubbles. Further typically the distance and/or space between the vane means limits the size of any bubbles, or vapour or gas pockets in the fluid pas sing through the apparatus .

In one embodiment the fluid passing through the apparatus is a partially saturated liquid. Typically the partially saturated liquid passes through and/or around the apparatus into an evaporator unit to turn into a partially or fully saturated gas.

In one embodiment the fluid passing through the apparatus is a partially saturated gas. Typically the partially saturated gas passes through and/or around the apparatus into a condenser unit to turn into a partially or fully saturated liquid.

In one embodiment the apparatus includes a body portion. Typically the body portion is a member from which the vane means extend. Further typically the body portion is an elongate linear member.

In one embodiment the body portion lies on and/or is positioned on the central longitudinal axis of the apparatus.

In one embodiment the body portion is substantially cylindrical in shape and/or circular is cros s-section when viewed along the longitudinal axis of the same. Typically, at least one end of the body portion tapers to a reduced diameter. Further typically both ends of the body portion taper such that the body portion is substantially lozenge shaped.

In one embodiment the apparatus includes one or more connecting portions. Typically the connecting portions include any one or any combination of protrusions, proj ections, recesses, apertures and/or the like. Further typically the connecting portions are located substantially at, or towards, the rear or bottom of the apparatus .

Preferably the connecting portions are complimentarily shaped such that the connecting portions on one apparatus can connect with, engage with, interlink and/or interconnect with the connecting portions on a second and/or further apparatus .

In one embodiment when the two or more apparatuses are connected the vane means substantially align and/or are coplanar. Typically two or more connected apparatuses form a single device or apparatus.

In a second aspect of the invention there is provided a method of optimising fluid flow in a heat exchange system and/or heat exchange system pipework, said method including inserting or positioning at least one apparatus into the fluid flow, said apparatus including at least two vane means extending along at least part of the length of the apparatus, wherein said vane means are arranged such that at least part, or a surface, of a first vane means is substantially parallel to at least part, or a surface, of a second and/or further vane means.

Typically the apparatus includes a housing. Further typically the apparatus including the housing is inserted into the pipework such that the housing is continuous with the pipe and/or pipework wall.

Preferably the cros s sectional area of fluid flow through the apparatus is substantially equal to and/or the same as the cros s sectional area of the pipe and/or pipework adj acent to the apparatus. As such, the diameter of the housing is larger than the diameter of the adj acent pipe and/or pipework the apparatus is connected to. This arrangement ensures that there is no significant pressure and/or temperature differential across the apparatus and/or adjacent pipework.

In one embodiment the system includes two or more apparatuses. Typically the two or more apparatuses are contained in a single housing.

In a third aspect of the invention there is provided a heat exchange system, said system including at least one evaporator and an apparatus suitable for optimising fluid flow in said system, said apparatus including at least two vane means for directing the flow of fluid through the apparatus, said vane means extending along at least part of the length of the apparatus, wherein said vane means are arranged such that at least part, or a surface, of a first vane means is substantially parallel to at least part, or a surface, of a second and/or further vane means. In one alternative embodiment the head exchange system includes at least one distributor. Typically the apparatus is located upstream of the at least one distributor.

Typically the apparatus is fitted into and/or incorporated on new heat exchange systems.

In one embodiment the apparatus is fitted to an existing heat exchange system. Typically the apparatus is retrofitted and/or inserted into any one or any combination of the tubing, tubework, pipes, pipework and/or the like of an existing system.

Specific embodiments of the invention are now described with reference to the following figures.

Figures l a and l b show front and rear isometric views of one embodiment of the present invention;

Figure 2 shows a side on cros s sectional view of one embodiment of the apparatus; and

Figure 3a shows a perspective view of the apparatus housing and figure 3b shows an exploded view of the housing and contents in accordance one embodiment of the invention.

The present invention provides a device that has two effects on the flow of fluid inside a heat exchanger system. Firstly the device divides, limits and/or otherwise restricts the size of any bubbles in the fluid flow. Secondly the fluid flows past a plurality of directional vane means or fins which cause the fluid to rotate. Turning firstly to figures l a and l b where there is shown a device 2 which includes a central body portion 4 from which a number of blades or fins 8 extend. The central body portion 4 is cylindrically shaped and tapers to a narrower point at one end thereof. The fins 8 are planar blades are offset and/or placed angularly in relation to the longitudinal axis along which the body portion 4 lies. As such, the fluid which flows past the device in use is directionally influenced to flow helically or spirally by the angled fins 8. The rotating flow field or vortex created in the fluid causes any vapour bubbles to concentrate near to the centre of the tube in which the device is situated in use, and liquid accumulates or collects at the tube wall accordingly. Thus, on entering a distributor (not shown) any phase separation occurring will remain and each phase is less likely to interfere with the other by way of preventing agglomeration of gas pockets and/or bubbles . Typically, the rotation ensures the fluid is presented to the entry apertures on the distributor in substantially the same condition.

In addition to creating a helical flow in the fluid, the fins 8 also have a second function to divide or substantially limit the size of any bubbles passing through the device 2. This is achieved by creating channels of a predetermined size by selecting the distance between adj acent fins and/or the diameter or size o f the fins and thus the distance to the tube or housing wall in which the device is situated. Figure 2 shows a cross section A-A along the length of the device. In this example the device is enclosed inside a housing 6 which is continuous with the pipework 10 in which the device is situated. These channels are formed having walls defined by at least part o f the body portion 4, adj acent fins 8 and the inner housing wall or surface.

In conventional vapour compression refrigeration systems liquid refrigerant fluid leaves the condenser and enters the expansion valve as a sub-cooled liquid usually within a few temperature degrees of saturation. As the refrigerant fluid flows through the expansion valve it undergoes isenthalpic expansion and leaves as a wet-vapour with a drynes s fraction or quality value of not usually more than 10%, depending upon the pres sure drop. In such a wet-vapour condition the structure of the fluid flow can be described as either bubble, slug or annular, depending on the drynes s fraction. The most likely condition at the dryness fraction values encountered however are either bubble-flow or slug-flow. In the latter case the refrigerant fluid moves along the distributor supply pipe in alternating 'slugs' of liquid followed by large bubbles of saturated vapour. It is slug-flow that causes the distributor problems in metering in equal proportions to every tube circuit if each circuit is to provide the same amount of cooling. In an evaporator it is the liquid refrigerant boiling to vapour that the produces the cooling effect and therefore it is neces sary that the distributor feeds each tube circuit with the same quantity or amount of liquid refrigerant. This is achieved in the present invention by splitting, dividing or otherwise limiting the size of the bubbles making up the slug-flow passing through the device.

The example in figure 2 also shows that two devices are interlinked by formations 12 to form a single apparatus or device. The formations are a number of correspondingly shaped proj ections and recesses that engage and or interlink. In this example the formations 12 are arranged such that the fins 8 on each device sit in a co-planar fashion and/or on the same plane. Thus the channel formed by the coplanar fins is continuous .

Figure 2 also shows that the front or rear edges of the fins 8 are angled to conform and/or fit closely to the angled walls of the housing 6. In addition, in this example the housing 6 includes an additional inner wall 14 that sits within the grooves or recesses in the peripheral edge of the fins 8.

Turning now to figure 3a which shows an external view of the device housing 6, 14. It can be seen that the diameter of the housing is larger than the diameter of the tubing 10 into which it is spliced or inserted. The diameter of the tubing and/or the dimensions of the device 2 are carefully selected or predetermined such that although the diameter increases, the volume of the passage and/or the cross-sectional area of the pas sage through which the fluid flows remain constant. This minimises any pres sure los s caused by the insertion of the device.

Figure 3b is an exploded view of one embodiment of the apparatus wherein two devices are attached tail-to-tail to form a single device. The advantage of this arrangement is that is the device can be provided in a housing which can be fitted either way into a heat exchanger's tubing without the engineer having to determine the direction of fluid flow. Essentially the hydrodynamically shaped body 4 and fins 8 ensure that the device cannot be fitted back to front. The person skilled in the art will appreciate that although in this example such a device is formed of two parts, the device could be manufactured in such a way so as to comprise a single unit or a kit of parts that could be assembled to form a single device.