APPARATUS AND METHOD FOR PROVIDING PURIFIED WATER

Abstract

A water purification apparatus including a first water purification station for a first internal purified water stream. A valve selects either a first dispense purified water stream or a first continuing water stream or both. An internal reservoir receives the first continuing water stream to hold a volume of second purified water, and provides a second internal purified water stream. A second valve able dispenses the second dispense purified water stream. A second water purification station receives the second internal purified water and provides a third internal purified water stream. A third valve selects from the third internal purified water stream either a third dispense purified water stream, or a third continuing water stream, or both. A recirculation loop returns the third continuing water stream into the internal reservoir. A pump pumps the second internal purified water stream from the internal reservoir around the recirculation loop.

Claims

1. A water purification apparatus able to provide at least three dispense purified water streams of different water purities from the water purification apparatus, comprising at least: (i) a water inlet stream; (ii) a first water purification station comprising one or more first water purification process units connected to the water inlet and able to provide a first internal purified water stream; (iii) a first valve able to select from the first internal purified water stream either a first dispense purified water stream or a first continuing water stream or both; (iv) an internal reservoir within the water purification apparatus adapted to receive the first continuing water stream through a water inlet, to hold a volume of second purified water, and to provide a second internal purified water stream, (v) a second valve able to dispense a second dispense purified water stream from the water purification apparatus; (vi) a second water purification station comprising one or more second water purification process units able to receive the second internal purified water as a second continuing water stream and able to provide a third internal purified water stream; (vii) a third valve able to select from the third internal purified water stream either a third dispense purified water stream, or a third continuing water stream, or both; (vii) a recirculation loop able to return the third continuing water stream into the internal reservoir; and (ix) a pump able to pump the second internal purified water stream from the internal reservoir around the recirculation loop.

2. A water purification apparatus as claimed in claim 1 wherein the first and second water purification stations include at least a deioniser.

3. A water purification apparatus as claimed in claim 2 wherein the deioniser in the first water purification station is selected from a group comprising: a reverse osmosis unit, a capacitive deionisation unit.

4. A water purification apparatus as claimed in claim 2 wherein the deioniser in the second water purification station is selected from a group comprising of: ion exchange resin, electrodeionisation.

5. A water purification apparatus as claimed in claim 1 wherein the second water purification station includes an oxidiser.

6. A water purification apparatus as claimed in claim 5 wherein the oxidiser provides oxidation selected from a group comprising: UV oxidation, ozonation, electrochemical oxidation, ultrasonic oxidation.

7. A water purification apparatus as claimed in claim 1 wherein at least one of or each of the first, second and third dispense purified water outlet streams is pressurised or pumped.

8. A water purification apparatus as claimed in claim 1 wherein the third dispense purified water stream is of greater purity than the second dispense purified water stream.

9. A water purification apparatus as claimed in claim 1 wherein the third dispense purified water stream is ultra-pure water of resistivity >15 MΩ.Math.cm.

10. A water purification apparatus as claimed in claim 1 wherein the second dispense purified water stream is of greater purity than the first dispense purified water stream.

11. A water purification apparatus as claimed in claim 1 wherein the second dispense purified water stream has a resistivity of >1 MΩ.cm.

12. A water purification apparatus as claimed in claim 1 wherein the first dispense purified water stream is of greater purity than the inlet water stream (12).

13. A water purification apparatus as claimed in claim 1 wherein the first dispense purified water stream has a resistivity of >0.05 MΩ.Math.cm.

14. A water purification apparatus as claimed in claim 1 wherein the second dispense purified water stream is provided from the recirculation loop.

15. A water purification apparatus as claimed in claim 14 wherein the second valve is able to select from the second internal purified water stream either the second dispense purified water stream, or the second continuing water stream, or both said streams.

16. A water purification apparatus as claimed in claim 1 wherein the second dispense purified water stream is provided from the internal reservoir.

17. A water purification apparatus as claimed in claim 1 provided within a single housing containing the first and second water purification stations, the internal reservoir, a control system, and the pump.

18. A water purification apparatus as claimed in claim 17 further including one or more water connections able to extend the third dispense purified water stream or the recirculation loop beyond or outside the housing.

19. A water purification apparatus as claimed in claim 1 being a portable water purification apparatus.

20. A water purification apparatus as claimed in claim 1 having a mass of <22 kg when the reservoir is full of water, or a mass of <15 kg when the reservoir is empty of water.

21. A water purification apparatus as claimed in claim 1 further comprising a first water quality measurement device to measure the water quality of the second purified water in the internal reservoir, and a reservoir level sensor able to measure the volume of the second purified water in the internal reservoir.

22. A water purification apparatus as claimed in claim 21 further comprising means to calculate the water quality of the first internal purified stream from the measurements of the first water quality measurement device and the reservoir level sensor.

23. A water purification apparatus as claimed in claim 1 further comprising a grey water outlet stream from the first water purification station.

24. A method of providing at least three dispense purified water streams from a portable water purification apparatus comprising at least the steps of: (a) passing a water inlet stream through a first water purification station comprising one or more first water purification process units to provide a first internal purified water stream that is of higher purity than the water inlet stream, (b) providing by selecting from the first internal purified water stream, either a first dispense purified water stream, or a first continuing water stream, or both; (c) passing the first continuing water stream to an internal reservoir within the water purification apparatus through a water inlet, the internal reservoir holding a volume of second purified water, and providing a second internal purified water stream from the reservoir, (d) providing by selecting, either from the reservoir or from the second internal purified water stream, a second dispense purified water stream, or a second continuing water stream, or both; (e) passing the second continuing water stream to a second water purification station comprising one or more second water purification process units, and providing a third internal purified water stream that is of higher purity than the second continuing water stream; (f) providing by selecting from the third internal purified water stream, either a third dispense purified water stream, or a third continuing water stream, or both; (g) recirculating any third continuing water stream into the internal reservoir around a recirculation loop; (h) pumping the second internal purified water stream from the internal reservoir around the recirculation loop.

25. A method as in claim 24 further comprising calculating the purity of the purified first internal purified water stream by measuring the conductivity of the second internal purified water stream.

26. A method as in claim 24 further comprising varying the speed of the recirculation loop.

Description

[0071] Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:

[0072] FIG. 1 is a simplified schematic view of a water purification apparatus and method that provides three dispense purified water streams of three different purities according to embodiments of the present invention;

[0073] FIG. 2 is a schematic view of a first water purification apparatus and method according to a first embodiment of the present invention; and

[0074] FIG. 3 is a schematic view of a second water purification system and method according to a second embodiment of the present invention; and

[0075] FIG. 4 is a schematic view of a third water purification system and method and means for monitoring the purity of each of the three different water purities according to a further embodiment of the present invention; and

[0076] FIG. 5 is chart detailing conductivity as measured by a first conductivity cell used to indirectly determine the conductivity of a first internal purified water stream involved in the present invention.

[0077] Referring to the drawings, FIG. 1 shows a water purification apparatus that provides three outlet purified water streams of three different purities.

[0078] FIG. 1 is a simplified schematic diagram of one embodiment of the present invention, based on a water purification apparatus 10 having an inlet for connection to a supply of potable or similar water from within a laboratory, for a suitable water inlet stream 12, and three or four dispense outlets, one for each of a first dispense purified water stream 22, a second dispense purified water stream 46, a third dispense purified water stream 56, and an optional grey water outlet stream 16.

[0079] FIG. 2 shows a schematic diagram of a first embodiment of the water purification apparatus 10, the outside of which is shown by the dashed lines. Connections to a laboratory water supply, and for the passage of water within the water purification apparatus 10, are made by pipe or tube as known in the art.

[0080] The pipe for the water inlet stream 12 is connected to an inlet electrically activated valve 13, such as a solenoid valve, to control the flow of water into the apparatus 10. The outlet from the inlet solenoid valve 13 is connected to the first water purification station 14, able to purify the water inlet stream 12 to create a first purified water, which exits the first water purification station 14 as a first internal purified water stream 18.

[0081] The first water purification station 14 contains one or more deionising technologies, such as reverse osmosis or capacitive deionisation, to achieve the purification, and a grey water outlet stream 16 to discharge the ions removed by the deionising technologies and to provide a water stream that may be used for general purposes in the laboratory where water purity is not of concern.

[0082] The first water purification station 14 may also contain other technologies able to filter the inlet water stream 12, to remove particles prior to the deionising technology.

[0083] The first water purification station 14 may further contain technologies such as activated carbon, to remove chlorine or chloramines from the inlet water stream 12 prior to the deionising technology.

[0084] The first water purification station 14 may further contain technologies such as ion exchange resin to soften the inlet water stream 12 by exchanging divalent ions for sodium ions after the deionising technology.

[0085] The skilled man can see that the first water purification station 14 may include one or more water purification process units able to provide one or more of the above technologies, and generally known in the art.

[0086] The first internal purified water stream 18 is passed to a first valve 20, preferably an electrically actuated valve such as a solenoid valve, for selectively passing the first internal purified water stream, 18 to either a first purified water outlet as a first dispense purified water stream 22 from the water purification apparatus 10, or to an internal reservoir 26 as a first continuing water stream 21.

[0087] The internal reservoir 26 can be any suitable shape and design and volume. Optionally, the internal reservoir has a volume in the range of 3 to 10 litres, and has a first inlet 24 for the first continuing water stream 21. The internal reservoir 26 may also have an outlet 29 for water to exit into a recirculation loop 36, and a second inlet 32 for the returning recirculated water as described hereinafter.

[0088] The internal reservoir 26 contains a second purified water 28, being a mixture of first continuing water stream 21 that has entered by first purified water inlet 24, and water that has entered by the second water inlet 32 which is more purified than the first continuing water stream 21 as described hereinafter.

[0089] The internal reservoir 26 also contains a composite vent filter 34 to allow air passage into and out of the reservoir 26, thus equilibrating the air pressure inside and outside the reservoir 26, while also preventing particles, bacteria or carbon dioxide from entering the reservoir 26.

[0090] The second purified water 28 is drawn from the internal reservoir 26 as a second internal purified water stream 30, and passed around the recirculation loop 36 by an in-line pump 38. A tee or tee-junction 40 in the recirculation loop 36, preferably located after the pump 38 (so that the second internal purified water stream 30 is under pressure or ‘pressurised’ relative to atmospheric pressure), allows the second internal purified water stream 30 to progress towards a second water purification station 48. Some of the second internal purified water stream 30 may also be passed via a flow limiter 42 and second valve 44, preferably an electrically operated valve, as a second dispense purified water stream, 46, from the water purification apparatus 10.

[0091] The flow limiter 42 ensures that only part of the second internal purified water stream 30 exiting the pump 38 can be output as the second dispense purified water stream, 46, and that a flow is maintained to the second water purification station 48 as a second continuing water stream 41.

[0092] The second water purification station 48 contains one or more deionising technologies, such as ion exchange resin or electrodeionisation, able to remove ions and dissolved carbon dioxide from the water therein, to create a third purified water, which exits the second water purification station 48 as a third internal purified water stream 50. The second water purification station 48 may have a waste stream (not shown), that can be return water containing ions removed from the second water purification station 48 to a point prior to the first water purification station 14, or passed from the unit through the grey water outlet stream 16.

[0093] The second water purification station 48 may further contain oxidative technologies such as UV oxidation or ozone or peroxide production to remove viable bacterial contamination from the water.

[0094] The second water purification station 48 may further contain oxidative technologies such as UV, ozone, peroxide, sonolysis or electrochemical oxidation to break down organic molecules from the water.

[0095] The second water purification station 48 may further contain molecular filtration by size exclusion, such as microfiltration or ultrafiltration or by charged filters, to remove bacteria, molecules and particulate contamination from the water.

[0096] The third internal purified water stream 50 exiting the second water purification station 48 is passed to a third valve 54, optionally an electrically activated valve such as a solenoid valve, from which it is either returned to the internal reservoir 26 through the second water inlet 32 as a recirculated water return stream 53, or some or all of the third internal purified water stream 50 may be passed from the water purification apparatus 10 as a third dispense purified water outlet stream 56.

[0097] FIG. 3 shows a second embodiment of a water purification apparatus of the present invention having a number of similar features to the embodiment shown in FIG. 2 (not discussed in detail), and therefore having some common notation with FIG. 2.

[0098] In FIG. 3, the second purified water 28 in the internal reservoir 26 may be taken directly from the reservoir 26 by the action of the second valve 44, which may be an electrically actuated valve or a hand operated valve. This may, depending on the valve aperture, allow a faster flow for the second dispense purified water stream 46, but the second dispense purified water stream 46 is not pressurised above that afforded by gravity.

[0099] In FIG. 3 the third internal purified water stream 50 exiting the second water purification station 48 is passed to a second tee or tee-junction 52, from which it is either returned to the reservoir 26 through the recirculated second water inlet 32 as recirculated water return stream 53, or some or all of the third internal purified water stream 50 may be passed from the water purification apparatus 10 as the third dispense purified water outlet stream 56 by the action of the third valve 54, optionally an electrically actuated valve. It is preferable for the third valve 54 to be highly adjustable, such as being a stepper motor valve. A suitable pressure sustaining device 58 on the return path recirculated water return stream 53 to the reservoir 26, can maintain an outlet pressure for the third dispense purified water stream 56.

[0100] FIG. 4 shows a third water purification apparatus that provides three outlet purified water streams of three different purities according to an embodiment of the present invention, and which also provides monitoring of the purity of each of the three different purities according to a further embodiment of the present invention.

[0101] The third water purification system 110 has the same or similar components and features of the first and second water purification apparatuses 10 in the previous figures, and so using some notation numbering of +100 to represent such components and features.

[0102] The third water purification apparatus 110 further includes (a) a first in line water quality measurement device 162 for measuring the conductivity of the second internal purified water stream 130 provided from the internal reservoir 126 and pump 138, and (b) a second in line water quality measurement device 164 for measuring the conductivity of the third internal purified water stream 150 provided from the second water purification station 148. The first and second water quality measurement devices 162, 164, may be conductivity cells as known in the art, preferably with cell constants of 0.02 or less.

[0103] The third water purification apparatus 110 further includes a level sensor 166 in the internal reservoir 126. The level sensor 166 provides a measurement of the amount of water in the reservoir 126.

[0104] The third water purification apparatus 110 further includes locations 168, 170 for connecting a remote dispenser, or for extending the recirculation loop 136 around a laboratory. If no remote dispenser or recirculation loop extension is required, then a link 172 is present.

[0105] The third water purification apparatus 110 further includes a control system, not shown, such as a printed circuit board including a microprocessor and input means. Readings from the first and second water quality measurement devices 162, 164 are processed by the microprocessor and water purity is output to a user by display means as known in the art.

[0106] When water is being recirculated around the recirculation loop 136, and the internal reservoir 126, is being filled with first continuing water stream 18, the microprocessor uses a known ‘lookup table’ and/or uses an algorithm to calculate the purity of the first continuing water stream 18.

[0107] FIG. 5 shows a curve of how the conductivity of water measured at the first water quality measurement conductivity device or cell 162 of the apparatus shown in FIG. 4, based on a volume in the recirculation loop 136 of 0.5 litres, and a recirculation flow rate of 1.0 l/min, will vary when 5 litres are taken from a 7 litre reservoir, and the reservoir is refilled back to 7 litres at a rate of 167 ml/min with a first purified water with a conductivity of 20 μS/cm.

[0108] At time=0 the internal reservoir 126 starts to fill and the conductivity of the second purified water in the internal reservoir 126 increases to a conductivity approaching a steady level. At time A at 30 minutes, the reservoir becomes full and a measurement of the conductivity “C(full)”, as measured at the first conductivity cell 162, is taken. The microprocessor can then compare conductivity C(full) to a lookup table or use an algorithm to determine the conductivity of the first continuing water stream 121 that has been fed into the reservoir 126.

[0109] For any particular equipment the volume of the reservoir and recirculation loop are fixed. The curve of conductivity approaches a steady level, presuming that the fill is for a long enough period. In the example described above, a fill of over 2.5 litres corresponding to 15 minutes is suitable.

[0110] Conductivity C(full) will be affected by changes in flow rate of the first purified water filling the reservoir or of the rate of flow of the recirculated water. Fill flow rate can be determined by monitoring the rate of change of level sensor 166. Variation in flow rate can then be added to the algorithm or adjustment made to the lookup table.

[0111] It is preferable to use a positive displacement pump 138 for the recirculation loop to provide a constant flow therein. Greater certainty of the flow can be achieved by the addition of a flow rate monitor in the recirculation loop and one may be desirable in the water purification system to provide a user with information regarding the amount of water he is dispensing.

[0112] An additional or alternative method for determining the conductivity of the first purified water is to measure the time taken to purify the second purified water to a known conductivity. An example in FIG. 5 is the time taken for the conductivity of the second purified water to reduce from C(full) to 0.5 μS/cm i.e. from t=A to t=B. Again, a lookup table or algorithm can be used to determine the conductivity of the first purified water.