GB1588120A

GB1588120A - Condenseres

Info

Publication number: GB1588120A
Application number: GB378980A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-12-06
Filing date: 1977-12-06
Publication date: 1981-04-15

Description

(54) IMPROVEMENTS IN AND RELATING TO CONDENSERS (71) I, PHILIP NEVILLE JUDSON, a British Subject of 27 Fincham's Close, Linton, Cambridge, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: Field of the invention This invention concerns condensers of the type used to condense vapours and the like.

Background to the invention Any cooled vessel can be used as a condenser and thus a piece of tube which is cooled by contact between its external surface and the surrounding air and into which hot vapour is passed will under appropriate circumstances act as a condenser. Greater efficiency is achieved by artificially cooling the tube and in the conventional Liebig condenser, the tube is surrounded by a second tube and the space between the two tubes is filled with water which is supplied to the space under pressure so as to be forced to flow therethrough and to constitute a cooling water jacket surrounding the inner tube.

Such condensers have a limited thermal capacity and it is possible for the condensing operation to cease partially or completely if there is a drop in the pressure of the water supplied to the water jacket.

Typical connections to the water jacket are simple push fit connections and a rise in water pressure can lead to a flooded laboratory.

Since such a condenser is usually attached to the cold water supply main, considerable variation in pressure can be expected during a 24-hour period and prob- lems such as those outlined can become of paramount importance if an experiment has to be carried out under controlled conditions for a long period of time or if the experimental apparatus has to be left unattended.

An alternative approach is to enclose the condenser in a heat sink.of metal or other material of good thermal conductivity. However, if it is required that the condenser be made of glass or other chemically resistant transparent material to enable the condensing space to be seen, the alternative approach has been considered inapplicable, as the opaque heat sink will cover the condensing space from view.

Disadvantages of known apparatus Conventional Liebig condensers require a large volume of water since they operate on a continuous flow basis, require to be located near to a tap on the cold water supply main and also require a suitable drain capable of handling the quantity of water which is to be discharged from the apparatus. It is not always convenient to provide such services and in any case the waste of water is undesirable. On the other hand, heat sinks of thermally conductive material prevent the condensing space from being seen.

Object of rhe invention With these defects in mind, it is an object of the present invention to provide an al ternative form of condenser for condensing hot vapours etc. which does not need to be connected to a water supply nor be located near to a drain, the operation of which does not involve the waste of considerable quantities of water, and which has a condensing space into which it is possible to see.

The invention According to the present invention apparatus for condensing hot vapours and the like comprises a transparent condenser tube the inside surface of which constitutes a condensing surface on which hot vapours and the like will condense, a heat sink of thermally conductive material, and means securing the heat sink to the tube so that at least part of the heat sink is in close contact with at least part of the external surface of the tube to cool the latter and assist in the condensing of host vapours on the inside thereof, wherein the heat sink does not completely surround the condenser tube so that a slit is left to enable the interior of the tube to be 'viewed.

As employed herein the term "heat sink" is intended to mean any body of thermally conductive material which is adapted to receive and readily dissipate heat by radiation and convection.

The heat sink may be joined to and supported by apparatus incorporating the condenser tube, but alternatively the apparatus containing the condenser tube may be supported by the heat sink.

According to another preferred feature the means securing the heat sink to the tube is adapted to accommodate small relative movement of one part of the apparatus relative to another to allow for the effects of unequal thermal expansion.

The heat sink may comprise a single member or may be formed from a plurality of members secured around the said tube.

The tube may be cylindrical in which event the heat sink or members forming the heat sink are formed with a complementary inner curved surface which fits snugly against the outer surface of the said cylindrical tube and with an outer surface which is formed into vanes to present a large radiating surface area.

A shield may be fitted below a heat sink to protect it from heat rising from apparatus located therebelow.

Conveniently the means securing the heat sink or members thereof in contact with the tube comprises springes or clips or connecting pieces of elastic material which are attached to or stretched around the heat sink.

Where a heat sink is employed which is formed from more than one member, the means securing the heat sink comprises springs or clips or connecting pieces of an elastic material which join the heat sink members one to another so as to encircle or partly encircle the tube.

A thermally conducting material may be inserted between the external surface of the tube and the inner surface of the heat sink or heat sink members, to improve thermal transfer. The thermally conducting material may be a flexible or compressible solid such as a plastics film, a soft metal or a compound metal and plastics film, or it may be a liquid or a semi-solid such as glycerol oil or grease.

The invention will now be described by way of example with reference to the accompanying drawings.

In the drawings Figure 1 is a perspective view of an embodiment of the invention, and Figure 2 is a plan view in cross-section on the line A-A of the embodiment shown in Figure 1.

Descriprion of embodirzent shown in rhe drawings In the embodiment shown in the drawings, the condenser comprises a cylindrical tube 48. Two heat sink sections 50 and 52 having vanes 54 and 56 and curved surfaces 58 and 60, each extend approximately one quarter the way round the outer surface of the tube 48, leaving elongate axial windows on opposite sides of the tube, of which only one 62 can be seen in the drawing.

The heat sink sections are linked the one to the other on the one side by means of spring metal clips 64, 66 and on the other side by either similar spring metal clips or rigid links of which one can be seen at 68 in Figure 2. The links or clips joining the heat sink sections are inserted into holes (not shown) drilled into the heat sink sections. Alternatively (not shown) they may be fitted into a raised flange on each heat sink rather than inserted into holes.

In use, heat from hot vapours entering the condensing space is transmitted through the walls of the condenser tube 48 to the heat sink sections 50, 52. The heat is transferred by conduction into the vanes 54, 56 from which it is transmitted by radiation and convection to the surrounding air. The heat sink sections may be blackened to improve their radiating efficiency.

For average ambient conditions in the range 15 to 200C, a condenser tube 48 100--400 mm long is required and the heat sink sections should have a combined surface area of 0.1 to 0.4 m2. These dimensions are suitable for most applications but different dimensions may be appropriate for special purposes. The ultimate limits are that the device should not be so small that the condensing space becomes choked by condensed vapours nor so large that its size causes inconvenience in use.

The condensing tube 48 may be made of any suitable transparent material which is generally chemically inert. In practice it will normally be of glass. The heat sink sections may be made of any thermally conductive material which is reasonably resistant to corrosion such as aluminium and its alloys, copper and its alloys, stainless steel or protected steel. Such material will invariably be opaque. Preferred material for the heat sink sections is aluminium or an aluminium alloy.

In order to improve the thermal transmission through a glass walled tube such as 48, a strip or wire of metal such as copper may be embedded in the wall of the tube, typically in the form of a helix the axis of which coincides with the axis of the tube.

In this way heat in the region of the windows and other uncooled parts of the tube will be conveyed more readily han otherwise would be the case, to the cooled regions of the tube in contact with the heat sink.

Where the wire is in the form of a helix the pitch is as small as possible whilst being consistent with the need to be able to see through the wall of the tube.

A temperature sensor such as a thermocouple may be atached to the heat sink and used to determine the operating temperature of the heat sink and as a corollary the operating temperature of the condenser. An electrical signal derived from the temperature sensor may be used after amplification to control the operation of a fan for cooling the heat sink and if the temperature is still exceeded to control the shutting down of the p],ant (not shown) producing the vapour to be condensed.

WHAT I CLAIM IS:- f. Apparatus for condensing hot vapours and the like comprising a transparent condenser tube the inside surface of which constitutes a condensing surface on which hot vapours and the like will condense, a heat sink of thermally conductive material, and means securing the heat sink to the tube so that at least part of the heat sink is in close contact with at least part of the external surface of the tube to cool the latter and assist in the condensing of hot vapours on the inside thereof, wherein the heat sink does not completely surround the condenser tube so that a slit is left to enable the interior of the tube to be viewed.

2. Apparatus as claimed in claim 1, wherein slits for visibility of the condenser tube are formed by the heat sink or diametrically opposite sides of said tube.

3. Apparatus as claimed in claim 1 or claim 2 wherein the means securing the heat sink to the tube is adapted to accommodate a small relative movement of one part of the apparatus relative to another to allow for the effects of unequal thermal expansion.

4. Apparatus as claimed in claim 1 or claim 2 or claim 3 wherein the heat sink comprises a single member or a plurality of members secured around the said tube.

5. Apparatus as claimed in claim 4 in which the tube is cylindrical and the heat sink member or members are formed from a complementary inner surved surface which fits snugly against the outer surface of the cylindrical tube.

6. Apparatus as claimed in claim 5 in which the heat sink member or members is or are formed with radially directed vanes to present a large radiating surface area.

7. Apparatus as claimed in claim 4 wherein the means securing the heat sink to the tube comprises clips or connecting pieces of elastic material which are attached to or stretch around the heat sink or the members thereof, to join the heat sink members one to another so as to encircle the tube.

8. Apparatus as claimed in any of claims 1 to 7 wherein a thermally conducting material is tinserted between the external surface of the tube and the inner surface of the heat sink or heat sink members to improve thermal transfer therebetween.

9. Apparatus as claimed in claim 8 in which the thermally conducting material is a flexible or compressible solid such as a plastics film, a soft metal or a compound metal and plastics film or a liquid or a semisolid such as glycerol or oil or grease.

10. Apparatus as claimed in any of the preceding claims further comprising fan means for inducing a draught of air over the heat sink to improve the cooling characteristics thereof.

11. Apparatus as claimed in any of the preceding claims further comprising temperature sensing means for producing an electrical signal which is proportional to the temperature of the heat sink.

12. Apparatus as claimed in claim 11 wherein the electrical signal is employed to control the operation of the fan to cause the latter to operate and induce a cooling draught in the event that the temperature of the heat sink exceeds a predetermined value.

13. Apparatus as claimed in any of the preceding claims wherein the heat sink is formed from aluminium or an aluminium alloy.

14. Apparatus for condensing hot vapours and the like constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

consistent with the need to be able to see through the wall of the tube.

A temperature sensor such as a thermocouple may be atached to the heat sink and used to determine the operating temperature of the heat sink and as a corollary the operating temperature of the condenser. An electrical signal derived from the temperature sensor may be used after amplification to control the operation of a fan for cooling the heat sink and if the temperature is still exceeded to control the shutting down of the p],ant (not shown) producing the vapour to be condensed.

WHAT I CLAIM IS:- f. Apparatus for condensing hot vapours and the like comprising a transparent condenser tube the inside surface of which constitutes a condensing surface on which hot vapours and the like will condense, a heat sink of thermally conductive material, and means securing the heat sink to the tube so that at least part of the heat sink is in close contact with at least part of the external surface of the tube to cool the latter and assist in the condensing of hot vapours on the inside thereof, wherein the heat sink does not completely surround the condenser tube so that a slit is left to enable the interior of the tube to be viewed.
2. Apparatus as claimed in claim 1, wherein slits for visibility of the condenser tube are formed by the heat sink or diametrically opposite sides of said tube.
3. Apparatus as claimed in claim 1 or claim 2 wherein the means securing the heat sink to the tube is adapted to accommodate a small relative movement of one part of the apparatus relative to another to allow for the effects of unequal thermal expansion.
4. Apparatus as claimed in claim 1 or claim 2 or claim 3 wherein the heat sink comprises a single member or a plurality of members secured around the said tube.
5. Apparatus as claimed in claim 4 in which the tube is cylindrical and the heat sink member or members are formed from a complementary inner surved surface which fits snugly against the outer surface of the cylindrical tube.
6. Apparatus as claimed in claim 5 in which the heat sink member or members is or are formed with radially directed vanes to present a large radiating surface area.
7. Apparatus as claimed in claim 4 wherein the means securing the heat sink to the tube comprises clips or connecting pieces of elastic material which are attached to or stretch around the heat sink or the members thereof, to join the heat sink members one to another so as to encircle the tube.
8. Apparatus as claimed in any of claims 1 to 7 wherein a thermally conducting material is tinserted between the external surface of the tube and the inner surface of the heat sink or heat sink members to improve thermal transfer therebetween.
9. Apparatus as claimed in claim 8 in which the thermally conducting material is a flexible or compressible solid such as a plastics film, a soft metal or a compound metal and plastics film or a liquid or a semisolid such as glycerol or oil or grease.
10. Apparatus as claimed in any of the preceding claims further comprising fan means for inducing a draught of air over the heat sink to improve the cooling characteristics thereof.
11. Apparatus as claimed in any of the preceding claims further comprising temperature sensing means for producing an electrical signal which is proportional to the temperature of the heat sink.
12. Apparatus as claimed in claim 11 wherein the electrical signal is employed to control the operation of the fan to cause the latter to operate and induce a cooling draught in the event that the temperature of the heat sink exceeds a predetermined value.
13. Apparatus as claimed in any of the preceding claims wherein the heat sink is formed from aluminium or an aluminium alloy.
14. Apparatus for condensing hot vapours and the like constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.