GB2226253A

GB2226253A - Liquid distillation apparatus

Info

Publication number: GB2226253A
Application number: GB8829994A
Authority: GB
Inventors: Leung Sui Ki
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-12-22
Filing date: 1988-12-22
Publication date: 1990-06-27
Also published as: GB8829994D0

Abstract

There is disclosed an apparatus for distilling a liquid, particularly water, which apparatus comprises an evaporation chamber 1 and a condensation chamber 2 linked by two passages 3, 4 so as to form a circuit. Parallel with this circuit is a refrigerant circuit 20 containing liquid refrigerant, which refrigerant circuit 20 runs through both the evaporation chamber 1 and the condensation chamber 2. Liquid refrigerant is compressed by a compressor 21 within the refrigerant circuit 20 and passes into the part of the refrigerant circuit 20 contained within the evaporation chamber 1 so as to heat unpurified water contained therein. Air is circulated around the circuit thus carrying water vapour produced in the evaporation chamber 1 to the condensation chamber 2. The liquid refrigerant, cooled by passing heat into the liquid within the evaporation chamber 1 passes around the refrigerant circuit 20 to that part of the refrigerant circuit 20 contained within the condensation chamber 2 wherein heat is passed from the water vapour therein back to the liquid refrigerant, thus condensing the water vapour to give substantially pure water. <IMAGE>

Description

Title: Liquid Distillation Apparatus.

THE PRESENT INVENTION relates to the purification of a liquid by distillation and more particularly to the purification of water by distillation.

According to the present invention there is provided apparatus for distillation of a liquid, the apparatus comprising an evaporation chamber, a condensation chamber, passage means for allowing passage of vapour from the evaporation chamber to the condensation chamber, means for, in use, evaporating liquid contained in the evaporation chamber, and means for, in use, condensing vapour contained in the condensation chamber, wherein the evaporating means and the condensing means comprise a heat exchanger.

Preferably the evaporation chamber comprises a drain for, in use, draining liquid therefrom. The drain may be opened and closed by means of a valve which may be controlled by a timer so as to automatically drain the evaporation chamber at predetermined intervals.

Preferably the evaporation chamber comprises an inlet port for allowing passage of liquid to be distilled into the evaporation chamber, the inlet port preferably comprising a valve for regulating the influx of liquid to be distilled into the evaporation chamber.

Furthermore, it is preferable that the evaporation chamber comprises means for measuring the level of liquid in the evaporation chamber. In such circumstances, the valve in the inlet port may be controllable in response to the means for measuring the level of liquid. The valve in the inlet port may also be controlled in response to a timer used for timing the opening and closing of a valve in a drain for the evaporation chamber.

Preferably the apparatus further comprises a collection chamber for collecting distilled liquid and second passage means for allowing passage of liquid from the condensation chamber to the collection chamber. More preferably the collection chamber comprises means for measuring the level of liquid therein, the heat exchanger being controllable in response to the means for measuring the level of liquid in the collection chamber.

In one embodiment of the present invention, the first passage means, for allowing passage of vapour from the evaporation chamber to the condensation chamber, comprises a first passage connecting the evaporation chamber and the condensation chamber, a second passage connecting the evaporation chamber and the condensation chamber and means for circulating fluid around the circuit formed by the first passage, the evaporation chamber, the second passage and the condensation chamber.

Preferably the heat exchanger comprises a circuit containing a liquid refrigerant. In an embodiment of the present invention, a first part of the circuit is contained within the evaporation chamber and a second part of the circuit is contained within the condensation chamber.

Preferably the heat exchanger comprises a compressor for compressing refrigerant. In another embodiment of the present invention the flow rate of refrigerant through the circuit is controlled by a section of the circuit comprising a capillary tube.

The pressure within the distillation apparatus may be balanced with the atmosphere by means of an opening having an air filter therein so as to prevent ingress of particles from the atmosphere outside the distillation apparatus.

The present invention also relates to a method of distilling liquid, preferably water, using the apparatus according to the present invention.

For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawing in which: Figure 1 is a schemetic view of an apparatus according to one embodiment of the present invention.

The apparatus shown in Figure 1 comprises an evaporation chamber (1) and a condensation chamber (2) which chambers are independently linked by a vapour passage (3) and a circulation passage (4). A water pipe (5) carrying water to be distilled opens into the evaporation chamber (1) at the top thereof. Within the waterpipe (5) is positioned a valve (6).

At the bottom of the evaporation chamber (1) is a drain outlet (7) within which is positioned a valve (8). Within the evaporation chamber (1) is a thermostat (9), for measuring the temperature of water contained within the evaporation chamber (1), and a water level limit detection device (10). The valve (8) within the drain outlet (7) is controllable by means of a timer (not shown) and the valve (6) within the waterpipe (5) is controllable by the timer and by the water level limit detection device (10). The inlets, to the evaporation chamber (1), of the vapour passage (3) and the circulation passage (4) are positioned above the upper limit of water containable within the evaporation chamber (1) as defined by the water level limit detection device (10).

At the bottom of the condensation chamber (2) is a water passage (11) which water passage (11) connects the condensation chamber (2) with a collection chamber (12) positioned beneath the condensation chamber (2). At the top of the condensation chamber (2) is a first pressure outlet (13) which pressure outlet (13) is open to the atmostphere and has fitted therein an air filter (14) to prevent ingress of dust and other particles from the atmosphere to the distillation apparatus.

At the top of the collection chamber (12) is positioned a second pressure outlet (15) having therein a second air filter (16). At the bottom of the collection chamber (12) is positioned a water outlet (17), such as a tap, to allow removal of water from the collection chamber (12). Within the collection chamber (12) is positioned a second water level limit detection device (18) for detecting when the collection chamber (12) is full (in this embodiment containing about 20 to 25 litres of water).

Positioned within the circulation passage (4) is a fan (19), in this embodiment a 20 watt electric fan, for circulating air around the circuit formed by the circulation passage (4), the top of the evaporation chamber (1), the vapour passage (3) and the condensation chamber (2).

The apparatus further comprises a refrigerant circuit (20). This refrigerant circuit comprises a refrigerant compressor (21) for circulating the refrigerant around the refrigerant circuit, a capillary tube (22) for limiting the flow of refrigerant around the circuit and a water remover (23) to remove any water which may contaminate the refrigerant contained within the circuit.

The remainder of the circuit is made up of tubing of high grade stainless steel. Part of this tubing is formed into two separate coils, a first coil (25) contained within the part of the evaporation chamber (1) below the upper limit of liquid containable therein, as defined by the water level limit detection device (10) and second coil (26) contained within the condensation chamber (2).

In the refrigerant circuit shown in Figure 1, the compressor (21) is an 0.5 to 0.75 kilowatt closed type compressor and the refrigerant used is R-12.

To distill water using the apparatus of Figure 1, the evaporation chamber (1) is first filled by opening the valve (6) in the water pipe (5) which is connected to a water source such as tap water. The evaporation chamber (1) will then fill to the level detectable by the water level limit detection device (10). At this point the water level limit detection device (10) will control the valve (6) within the waterpipe (5) so as to close the valve (6) within the waterpipe (5) and thus cease the flow of water into the evaporation chamber (1). In this way any overfilling of the evaporation chamber (1) may be prevented.

The refrigerant circuit (20) is then operated by starting the refrigerant compressor (21). This compressor (21) will compress the refrigerant therein and so vapourise the refrigerant, thereby increasing its temperature. The refrigerant will then pass into the first coil (25) which is, at this point, submerged beneath the water in the evaporation chamber (1). Heat will then pass from the refrigerant within the first coil (25) through the tubes (24) of the first coil (25) into the water within the evaporation chamber (1), thereby heating the water within the evaporation chamber (1).The thermostat (9) is adapted to maintain the temperature of the water within the evaporation chamber (1) at a temperature at or below a predetermined temperature, preferably 65or. If the temperature of the water within the evaporation chamber (1) rises above the predetermined temperature this rise will be detected by the thermostate (9) which then controls the refrigerant compressor (21) so as to turn off the refrigerant compressor (21) until the temperature of the water within the evaporation chamber (1) has dropped below 650 C, at which point the refrigerant circuit (20) will operate again.

The heat absorbed by the water within the evaporation chamber (1) from the first coil (25) will cause the water to vapourise, the vapour rising above the surface of the water to the upper part of the evaporation chamber (1). The electric fan (19) is then operated to cause circulation of gas through the circulation passage (4) into the evaporation chamber (1), along the vapour passage (3) and into the condensation chamber (2), thereby carrying water vapour from the evaporation chamber (1) to the condensation chamber (2).

It will be appreciated that although the water within the evaporation chamber (1) will be evaporated by the heat generated from the first coil (25), particulate material within the water contained within the evaporation chamber (1) such as mineral ions, micro-organisms, and other contaminants will not be vapourised and, therefore, the vapour carried from the evaporation chamber (1) to the condensation chamber (2) via the vapour passage (3) will be substantially pure water vapour.

The refrigerant contained within first coil (25), by transfering heat to the water within the evaporation chamber (1), will condense to a liquid. This liquid will be driven, by the pressure of refrigerant vapour generated by the refrigerant compressor (21), along the refrigerant tubes (24) to the capillary tube (22) positioned just before the refrigerant tube (24) enters the condensation chamber (2).

This capillary tube (22) serves to regulate the flow rate of the refrigerant within the refrigerant circuit (20). The refrigerant then passes into the second coil (26) within the condensation chamber (2), at low pressure and, thus, low temperature. Within the condensation chamber (2) the refrigerant within the second coil (26) is considerably cooler than the water vapour surrounding the second coil (26).

Accordingly, heat will pass from the water vapour contained within the condensation chamber (2) through the stainless steel of the refrigerant tube (24) into the refrigerant contained therein. This will cause the water vapour to condense within the condensation chamber (2) and collect in the bottom thereof. The water condensed within the condensation chamber (2) has condensed from substantially pure water vapour and, accordingly, is substantially free from the particulate matter which is found in the water which was originally in the evaporation chamber (1).

The refrigerant within the second coil (26) will be heated by the heat of the water vapour within the condensation chamber (2) passing thereto and will vapourise. The refrigerant then passes round the refrigeration circuit (20) through the water remover (23) towards the compressor (21) condensing as it does so. The refrigerant is driven towards the compressor (21) by the suction effect caused by the compressor (21) vapourising refrigerant and passing it towards the first coil (24). In this way refrigerant will circulate around the refrigerant circuit (20) during operation of the refrigerant condenser (21).

The substantially pure water collecting in the bottom of the condensation chamber (2) will flow through the water passage (11) into the collection chamber (12). Accordingly, the collection chamber (12) will fill with substantially pure water. When the collection chamber (12) is full to its capacity, of about 20 to 25 litres, the level of the substantially pure water therein will be detected by the second water level limit detection device (18). This second water level limit detection device (18) controls the refrigerant compressor (21) and turns off the refrigerant compressor (21), thereby ceasing circulation of refrigerant round the refrigerant circuit (20), so stopping the distillation process to prevent any more water in the evaporation chamber (1) being distilled and thereby overfilling the collection chamber (12).When substantially pure water is drawn off from the collection chamber (12) by means of the water outlet (17) the level of the water within the collection chamber (12) will decrease and, will no longer be detected by the second water level limit detection device (18) which will then automatically re-start the refrigerant compressor (21) so as to recommence the distillation process to re-fill the collection chamber (12) with substantially pure water.

Similarly, as water is evaporated from the evaporation chamber (1) the water level within the evaporation chamber (1) will drop. In these circumstances the first water level limit detection device (10) will no longer detect the level of the water in the evaporation chamber (1) and so will automatically open the valve (6) within the waterpipe (5) to allow ingress of more water to the evaporation chamber (1) so as to maintain the evaporation chamber (1) filled at all times.

However, it will be appreciated that, by distilling substantially pure water from the water contained within evaporation chamber (1), the concentration of contaminants and other particulate matter within the water in the evaporation chamber (1) will gradually increase as the distillation process continues. Accordingly, a timer mechanism is provided to control the valve (8) within the drain outlet (7). This timer further controls the valve (6) within the waterpipe (5), over-riding the control of the first water level limit detection device (10). At given intervals, for example every 24 hours, the timer circuit will operate, thereby opening the valve (8) within the drain outlet (7) and closing the valve (6) within the waterpipe (5). In this way the water within the evaporation chamber (1), having a high concentration of contaminants, will drain from the drain outlet (7).At the same time, no water will be wasted, being poured into the evaporation chamber (1) only to drain therefrom immediately, by the automatic closing of the valve (6) within the waterpipe (5). After a predetermined amount of time, sufficient to drain the evaporation chamber (1) completely, the timer will then close the valve (8) in the drain outlet (7) and open the valve (6) within the waterpipe (5) to allow the evaporation chamber (1) to fill up with fresh water. At this point the over-riding control of the timer over the valve (6) is released and, therefore, when the evaporation chamber (1) is once again full to the predetermined level, this level is detected by the first water level limit detection device (10) and the valve (6) in waterpipe (5) is automatically closed.

In this way,a heat exchanger is used to produce water which is substantially pure and is particularly good for drinking.

Claims

1. Apparatus for distillation of a liquid, the apparatus comprising an evaporation chamber, a condensation chamber, passage means for allowing passage of vapour from the evaporation chamber to the condensation chamber, and means for, in use, evaporating liquid contained in the evaporation chamber, means for, in use, condensing vapour contained in the condensation chamber, wherein the evaporating means and the condensing means comprise a heat exchanger.

2. Apparatus according to Claim 1, wherein the evaporation chamber comprises a drain outlet for, in use, draining liquid from the evaporation chamber.

3. Apparatus according to Claim 2, wherein the drain outlet comprises a valve, the opening and closing of which is controllable by a timer.

4. Apparatus according to claim 1, 2 or 3, wherein the evaporation chamber comprises an inlet port for liquid to be distilled.

5. Apparatus according to Claim 4, wherein the inlet port comprises a valve for regulating influx of liquid to be distilled.

6. Apparatus according to Claim 5, wherein the evaporation chamber comprises means for, in use, measuring the level of liquid contained in the evaporation chamber, wherein the inlet port valve is controllable in response to the liquid level measuring means.

7. Apparatus according to Claims 5 or 6 when dependent upon Claim 3, wherein the inlet port valve is controllable by the timer.

8. Apparatus according to any one of the preceding claims, further comprising a collection chamber for, in use, collecting distilled liquid and second passage means for allowing passage of liquid from the condensation chamber to the collection chamber.

9. Apparatus according to Claim 8, wherein the collection chamber comprises second means, for, in use, measuring the level of liquid contained in the collection chamber wherein the heat exchanger is controllable in response to the second liquid level measuring means.

10. Apparatus according to any one of the preceding claims, wherein the first passage means comprises a first passage connecting the evaporation chamber and the condensation chamber, a second passage connecting the evaporation chamber and the condensation chamber and means for circulating fluid around the circuit formed by the first passage, the evaporation chamber, the second passage and the condensation chamber.

11. Apparatus according to any one of the preceding claims, wherein the heat exchanger comprises a refrigerant circuit containing a liquid refrigerant.

12. Apparatus according to Claim 11, wherein the refrigerant circuit comprises a compressor for, in use, vapourising the liquid refrigerent.

13. Apparatus according to Claim 11 or 12, wherein the refrigerant circuit passes through the evaporation chamber and/or the condensation chamber.

14. Apparatus according to Claim 11, 12 or 13, wherein the refrigerant circuit comprises a capillary tube for, in use, controlling the rate of flow of refrigerant liquid through the refrigerant circuit.

15. Apparatus according to any one of the preceding claims, further comprising a pressure equalisation aperture for, in use, balancing the pressure within the apparatus with atmospheric pressure, wherein the pressure equalisation aperture contains an air filter therein.

16. A method of distilling a liquid using the apparatus of Claims 1 to 15.

17. A method according to Claim 16, wherein the liquid distilled is water.

18. Apparatus for distillation of a liquid substantially as hereinbefore described with reference, to and as shown in, the accompanying drawing.

19. A method of distilling a liquid substantially as hereinbefore described.

20. Any novel feature or combination of features described herein.