EP0902872A1

EP0902872A1 - Heat exchanger

Info

Publication number: EP0902872A1
Application number: EP97924121A
Authority: EP
Inventors: David Mcivor Mowat; Ian David Cameron; Andrew Gunn
Original assignee: Iatros Ltd
Current assignee: Iatros Ltd
Priority date: 1996-06-05
Filing date: 1997-05-29
Publication date: 1999-03-24
Also published as: KR20000034779A; JP2000511628A; GB9611704D0; AU2969297A; WO1997046846A1

Abstract

The present invention relates to a heat exchanger (1) and in particular to a heat exchanger comprising a static mixer device (6) element (8) having a heat exchange surface in thermal connection with a temperature control means (7). Very efficient temperature control of fluids (17) can be achieved with the heat exchanger which produces a very thorough mixing of the fluid flow so that the fluid (17) in contact with the heat exchange surface (8) is repeatedly exchanged with other parts of the fluid flow so as to bring different parts of the fluid into contact with the heat exchange surface until substantially the whole of the fluid flow has been contacted by the heat exchanger (1) thereby facilitating a particularly accurate and uniform control of the temperature of the fluid flow. Fluids that may have their temperature controlled with the heat exchanger invention may be organic and/or inorganic and include for example water, biological fluids such as blood or plasma, food products such as mayonnaise, ice cream and industrial products such as paints, chemicals.

Description

HERT EXCHANGER

The present invention relates to heat exchangers.

5 Various heat exchangers are known in the art. These generally utilize a large multiplicity of planar fins to provide a large heat exchange surface in contact with a fluid flow past the heat exchanger. With such devices though only a small layer of fluid directly adjacent the heat exchange 0 surface can have its temperature effectively controlled within close limits. Accordingly if it is desired to achieve accurate and efficient temperature control it is necessary to provide a very large multiplicity of closely spaced fins throughout the whole cross-sectional area of fluid flow.

15 This can one the one hand provide significant resistance to the flow, and indeed obstruct the flow of suspended particulates, and on the other hand provide an obstruction to the passage of radiation through the flow path e.g. for treatment or inspection purposes. Such multi-finned elements 0 can moreover be relatively fragile and complex to manufacture.

It is an object of the present invention to avoid or minimise one or more of the above disadvantages. 5

We have now found that efficient temperature control of fluids can be achieved with a novel form of heat exchanger which produces a very thorough mixing of the fluid flow so that the fluid in contact with the heat exchange surface is d repeatedly exchanged with other parts of the fluid flow thereby bringing different parts of the fluid into contact with the heat exchange surface until substantially the whole of the fluid flow has been contacted by the heat exchanger thereby facilitating a particularly accurate and uniform

"5 control of the temperature of the fluid flow.

More particularly, the present invention provides a heat exchanger comprising a static mixer device element having a heat exchange surface in thermal connection with a temperature control means.

Various forms of temperature control means may be used. In one form of the invention this may comprise a conduit means for the passage of a heat exchange fluid through the interior of the static mixer device. In another form of the invention a solid state heat energy supply and/or drain device could be embedded in the static mixer device.

Various static mixer devices are known in the art. In general these comprise a static mixer device element longitudinally extending inside a sheath and having a series of wall means which, together with the sheath, repeatedly divide and remix the fluid flow through the static mixer device, as disclosed in, for example our earlier patent GB 2200020.

With a heat exchanger of the present invention it is possible to control the temperature of a wide variety of fluids across many different industries. Fluids may comprise: liquids, gases, and mixtures thereof, any of which may also contain suspended particulates. Such fluids may be organic and/or inorganic e.g. water, biological fluids such as blood or plasma, food products such as mayonnaise, ice-cream etc. and industrial products such as paints, chemicals etc.

In a further aspect the present invention provides a heat exchanger unit comprising a heat exchanger of the invention longitudinally extending inside a sheath between an inlet and an outlet thereof.

In yet another aspect the present invention provides a heat exchanger unit of the invention provided with a temperature detector for monitoring the temperature of fluid passing therethrough in use of the invention, a thermal energy supply and/or drain device, and a control means formed and arranged for adjusting the thermal energy supply/drain of said device in response to fluid temperature deviations from a desired value detected by said detector.

Where a heat exchanger using a heat exchange fluid passing therethrough is utilized then the thermal energy supply/drain device would normally include pump means for circulating the heat exchange fluid, and a remote thermal energy supply/drain device for adjusting the temperature of the heat exchange fluid passing through the heat exchanger.

A preferred form of heat exchanger has a series of helical wall segments extending along the outside of a central tubular core through which the heat exchange fluid circulates. Successive wall segments are angularly offset so that one flow exiting from between one set is divided into separate flows, with successive segments preferably winding in an opposed sense (clockwise - anticlockwise - clockwise etc.) to increase mixing.

The heat exchanger may be made of various materials but preferably is of a substantially inert metal with high thermal conductivity e.g. stainless steel.

Further preferred features and advantages of the invention will appear from the following detailed description given by way of examples and illustrated with reference to the accompanying drawings in which:

Fig. 1 is a partly schematic partly sectioned view of a heat exchanger device of the present invention.

Fig. 1 shows an apparatus 1 comprising a vessel 2 in the form of a cylindrical tube 3 with an inlet 4 and outlet 5, with an axially extending static mixer device 6 provided with temperature control means 7. In more detail the static mixer device 6 comprises an axially extending series of angularly offset helical "screw" elements 8 defining pairs of flow paths which are divided equally and mixed at the junctions 9 between successive elements 8 thereby providing a degree of mixing which increases exponentially with the number of elements used.

The "screw" elements 8 are mounted on a hollow core 10 which defines a heat exchange fluid passage 11 forming part of the temperature control means 7. In more detail the temperature control means 7 comprises a heat exchange fluid circuit 12 provided with pump means 13 for circulating the heat exchange fluid 12a therethrough and a remote Peltier-effect heat exchange device 14 provided with a control means 15 which has a temperature sensor 16 mounted inside the vessel 3 for monitoring the temperature of the fluid 17 undergoing irradiation. The control means 15 is formed and arranged for controlling the rate of cooling supplied so as to maintain a desired fluid temperature. This may be a fixed value, or more conveniently the control means 15 may be provided with user operable input means for varying the desired temperature setting.

The core 10 (and desirably also the screw elements 8) are of an inert physiologically acceptable thermally conductive material such as stainless steel in order to facilitate efficient thermal transfer between the fluid being treated 17 and the heat exchange circuit 7 thereby to control the fluid temperature closely within relatively narrow limits so as to on the one hand maximise the efficiency of the sterilisation/inactivation treatment and on the other hand to minimise any undesired denaturation or degradation of useful fluid components.

Claims

CIAIMS

1. A heat exchanger (1) comprising a static mixer device (6) element (8) having a heat exchange surface in thermal connection with a temperature control means (7) .

2. A heat exchanger (1) as claimed in claim 1 wherein said temperature control means comprises a conduit means (10) for the passage of a heat exchange fluid (12a) through the interior of said static mixer device (6) element (8) .

3. A heat exchanger (1) as claimed in claim 1 or claim 2 wherein a heat energy supply and/or drain device is provided in the static mixer device (6) element (8) .

4. A heat exchanger as claimed in any one of claims 1 to 3 wherein said static mixer device (6) element (8) is disposed longitudinally extending inside a sheath (3) and has a series of wall means which wall means together with said sheath (3) constitute a static mixer device (6) which repeatedly divides and remixes a fluid flow through said static mixer device (6) in use of the heat exchanger.

5. A heat exchanger (1) as claimed in claim 4 wherein said sheath (3) has an inlet (4) and an outlet (5) portion.

6. A heat exchanger (1) as claimed in any one of claims 1 to 5 wherein there is provided a temperature detector (16) for monitoring the temperature of a fluid (17) passing through said heat exchanger (1) in use thereof.

7. A heat exchanger as claimed in claim 6 when dependent on any one of claims 3 to 5 wherein there is provided a control means (15) formed and arranged for adjusting said thermal energy supply/drain device in response to fluid temperature deviations from a desired value detected by said detector (16) in use of said heat exchanger.

8. A heat exchanger (1) as claimed in any one of claims 2 to 7 when claim 3 is dependent on claim 2 which includes pump means (13) for circulating said heat exchange fluid (12a) .

59. A heat exchanger (1) according to any one of claims 2 to 8 when claim 3 is dependent on claim 2 wherein there is provided a remote thermal energy supply/drain device for adjusting the temperature of the heat exchange fluid (12a) passing through the heat exchanger (1) . 0

10. A heat exchanger (1) as claimed in any one of claims 2 to 9 when claim 3 is dependent on claim 2 which has a series of helical wall segments (8) extending axially along the outside of said conduit means (10) through which said heat exchange 5 fluid (12a) circulates, which segments (8) define pairs of fluid flow paths.

11. A heat exchanger (1) as claimed in claim 10 wherein said wall segments (8) are angularly offset so that one flow 0 exiting from between one set of segments (8) is divided into separate flows in which it is mixed with parts of another flow.

12. A heat exchanger (1) as claimed in claims 10 or 11 5 wherein said segments (8) wind successively in an opposed sense to increase mixing.

13. A heat exchanger (1) as claimed in any one of claims 1 to 12 wherein said heat exchange surface is made of a 0 substantially inert metal with high thermal conductivity properties.

14. A heat exchanger unit comprising a heat exchanger (1) according to claim 1 longitudinally extending inside a sheath 5 (3) between an inlet (4) and an outlet (5) thereof.

15. A heat exchanger unit according to claim 14 provided with: a temperature detector (16) for monitoring the temperature of a fluid (17) passing through said heat exchanger (1) , a thermal energy supply and/or drain device, and a control means (15) formed and arranged for adjusting the thermal energy supply/drain of said device in response to fluid temperature deviations from the desired value detected by said detector (16) .