BACKGROUND

Water is typically desalinated using thermal or membrane-based processes. Thermal methods, such as distillation, require a large input of energy to heat the water in order to vaporize it. Membrane-based processes, such as reverse osmosis and electrodialysis, typically use less energy than thermal processes, but substantial energy inputs are still required. Other issues with membrane dialysis technologies include the scale of production and the cost of chemical pretreatments. There remains a need, therefore, for improved methods of desalinating water which address the problems with current desalination processes.

SUMMARY

The present process comprises a method for separating impurities such as salt from impure water or other liquids. When water is purified by the present process, impure water is first directed to a longitudinally extending central conduit, preferably an upwardly extending conduit. The central conduit is in liquid communication with a proximal end of one or more rotating conduits which extend outwardly from the central conduit. The impure water is directed from the central conduit into the rotating conduits, with at least one of the rotating conduits comprising a nozzle. The rotating conduits are then rotated such that the nozzle travels at a speed which is within 5-10% of the speed of sound, more preferably within 1% of the speed of sound. The impure water is then discharged from the nozzle, thereby forming water vapor, after which the water vapor is collected.

Preferably, the nozzle is at the distal end of the rotating conduit. The central conduit is also preferably within a chamber, and the water vapor is collected in an upper portion of the chamber, where it condenses. A source of pressure is preferably used to drive the vapor upward, such as a vacuum source in the upper portion of the chamber. In one embodiment, the rotating conduit is in the form of a propeller, and in this case the propeller can drive water vapor toward the upper end of the chamber. Preferably, the central conduit is attached to the rotating conduits.

A device for use in the present methods can comprise, for example: a central conduit for receiving impure water, the central conduit being disposed within a device chamber, the device chamber comprising an upper portion and a lower portion;

one or more rotating conduits comprising a proximal end and a distal end, the proximal end of each of the rotating conduits being attached to the central conduit and being in liquid communication with the central conduit;

a nozzle on at least one of the rotating conduits for discharging liquid, the nozzle being in liquid communication with the rotating conduit; and

a condensation surface in an upper portion of the device chamber for collecting condensed water vapor discharged from the nozzle.

The present device preferably further comprises a collection chamber in the upper portion of the device chamber for collecting the condensed water vapor and a drain in the lower portion of the device for removing impurities and water from the device. It also preferably includes a source of vacuum pressure in an upper portion of the device chamber. The source of vacuum pressure can, for example, communicate with the device chamber through one or more openings, and the openings can include a mesh material on which liquid water can condense.

DRAWINGS

Figure 1 is a sectional view of an embodiment of the present system.

Figure 2 is a sectional view of an alternative embodiment of the present system.

Figure 3 is a sectional view of the embodiment of Figure 2 along line 3-3, showing a rotating conduit.

Figure 4 is a top plan view of the distal end of the rotating conduit of Figure 3 showing the discharge of water.

Figure 5 is a plan view of a screen used in the present system.

DESCRIPTION

The present system and method for purifying water discharges water at or near the speed of sound in order to purify it. Sound is a vibration that travels through an elastic medium as a compression wave, and the speed of sound describes how far this wave travels in a given amount of time. In dry air at 2O ⁰ C (68 ⁰ F), the speed of sound is 343 meters per second (1,125 ft/s) or 1,236 kilometers per hour (768 mph). This figure increases with gas temperature, and humidity can also cause the speed of sound to increase (generally by about 0.1%-0.6%).

Planes accelerating past the speed of sound have been observed to create a white halo formed by condensed water droplets. Such droplets are thought to result from a drop in air pressure around the aircraft as it accelerates past the sound barrier. Without being bound to a particular theory, it is believed that a pressure drop and/or transient vacuum occurring adjacent the nozzles of the present system as they are rotated at or near the speed of sound results in the evaporation or vaporization of water and other liquids discharged from such nozzles. In this way, water can be dissociated from contaminants such as salt or other impurities, and purified water or a purified aqueous mixture or fraction thereof can be collected.

Purification Process

In the present method, water in need of purification, such as salt water to be desalinized, is first conducted into a central conduit or pipe 1 extending along a longitudinal axis. Although desalinization is one application of the present system and method, ions, compounds, and other molecules carried in water can generally be removed from water in the present system and method, in particular if they are heavier than water molecules. In addition, other liquid admixtures can also be treated according to the present methods in order to remove impurities from such admixtures.

One or more peripheral conduits 3, preferably in the form of a propeller 12, extend outwardly from and are in fluid communication with the central conduit 1, and these peripheral conduits 3 are rotated about the longitudinal axis of the central conduit 1. The peripheral conduits 3 are preferably disposed outwardly from the central conduit 1 at an angle of approximately 90° with respect to the longitudinal axis of the central conduit 1, and are disposed so as to balance their mass around the central conduit 1 in order to provide for a balanced rotation about the longitudinal axis.

As the peripheral conduits 3 are rotated, saltwater or another aqueous solution or liquid to be purified is directed from the central conduit 1 into the rotating peripheral conduits 3 and sprayed out of a nozzle 8 which is placed on a distal portion of the peripheral conduit 3 that is traveling at approximately the speed of sound.

Preferably, the nozzle 8 is located at the furthest distal extent of the rotating conduit 3, but placement at a position proximal of this is also possible. In this case, the nozzle 8 is preferably placed at a location along the rotating conduit 3 which is or which can be rotated at approximately the speed of sound. Alternatively, the nozzle 8 can be placed adjacent a portion of the rotating conduit 3 which rotates at approximately the speed of sound.

The central conduit 1 and peripheral conduits 3 are rotated such that nozzles 8 are moving at a speed of between about 1,000 and 1,400 kilometers per hour, and preferably at a speed which is at or near the speed of sound. Such speeds are preferably within 10% of the speed of sound (i.e., between 10% below and 10% above the speed of sound), more preferably within 5% of the speed of sound, even more preferably within 2% of the speed of sound, and most preferably either at the speed of sound or within 1% of the speed of sound. In preferred embodiments the nozzles 8 of the present device are rotated at between 315 meters per second and 350 meters per second. As known to those of skill in the art, the speed of sound in air varies somewhat with ambient conditions, including humidity. The primary influence on the speed of sound however is temperature. Changes in the speed of sound over a range of temperatures is shown in Table 1 below.

Table 1:

Effect of Temperature on the Speed of Sound

Upon exiting the nozzle 8 at such speeds, an aqueous solution is vaporized, and at least some of the water is separated from the other constituents of the aqueous solution. Such water vapor is then conducted upward through the use of either positive or negative pressure. For example, a vacuum 5 or other source of negative pressure, and/or positive pressure from thrust generated by the peripheral conduits 3 (if they are, e.g., in the form of propellers), can be used in the embodiment of Figure 1 to draw the purified water upward to a collecting tank or chamber 11 of the present system, where it contacts a cap or other surface and condenses. The purified condensate is then collected.

Due to the heavier weight of salt and/or other constituents of the aqueous solution which have been separated from the water vapor as described above, such constituents will tend to fall and/or contact the inner surface of the tank 2 of the present system and then drain out through the lower end 19 of the tank 2. Salt or other impurities separated from the water may also associate with some of the vaporized water, and such associated molecules will likewise be heavier than the purified gas phase water. Such heavier molecules tend to fall and/or to hit the inner wall of the tank 2 and drain out from the salt drain 7. Depending on the amount of pressure used to drive water vapor to the upper portion 18 of the device (i.e., where collection chamber 11 is located), more or less of the total water vapor can be collected, and the extent of water purification can also be affected, since greater pressures may also drive more impurities into the collection chamber 11. If impurities which are lighter than water are present, water separated from such impurities would in this case be collected by collecting the heavier fraction of materials, i.e. those which fall to the lower portion of the present device. When liquids other than water are being purified, then the relative weight of the liquid and any entrained, dissolved, or otherwise admixed impurities should be evaluated in order to determine whether the purified liquid is to be collected in the upper portion of the present device or in the lower portion. Device

As shown in Figures 1 and 2, in one embodiment the present device comprises two propellers 12 positioned about a central conduit (or pole) 1 adjacent an upper end 18 and lower end 19 of a tank or other container capable of retaining vaporized liquid 2, though more rotating conduits 3 and/or rotating conduits having a different configuration can also be used. The tank 2, comprising a device chamber for receiving vaporized liquid, is preferably made from a rigid material capable of withstanding the pressure generated by the turning of the rotating conduits 3 (e.g., propellers 12) at or near the speed of sound and also capable of resisting chemical attack by the materials exiting the nozzles 8.

The propellers 12 each comprise a plurality of peripheral conduits 3 which are preferably shaped externally so as to direct vaporized water exiting the propellers 12 upward, i.e. converting some rotational motion into thrust. The central conduit 1 is in liquid communication with the peripheral conduits 3 and preferably is physically connected to the peripheral conduits 3, in which case rotation of the central conduit 1 also rotates the rotating conduits 3. A distal portion of the propellers 12 comprises a nozzle 8 which can be rotated at or near the speed of sound. In the embodiment shown in Figures 3 and 4, water exits nozzles 8 at the distal end of the peripheral conduits 3 of the propellers 12, but in other embodiments the nozzle 8 can be located more proximally, or additional nozzles proximal of the distal nozzle can be provided.

Saltwater or another aqueous solution or liquid to be purified is conducted into the central conduit 1 from a port, such as the injection pipe 4. After passing from the central conduit 1 into the propellers 12, the water is sprayed out of the distal end of the propellers 12 through a nozzle 8, as shown in Figure 4. Upon exiting the nozzle 8 while rotating at or near the speed of sound, the water is vaporized and enters a gaseous state. Such gaseous water or at least a portion thereof is desalinated (in the case of the treatment of saltwater). A source of vacuum 5 can then be used to draw the purified gas phase water upward. The spinning of the propeller 12 in this embodiment can also contribute to the movement of vaporized water upward. When the water vapor rises and contacts surfaces in the upper portion 18 of the tank 2, it will condense. Such water will be purified relative to the impure water conducted into the central conduit 1. In the embodiment of Figure 1, the water vapor passes through one or more water pipes 9 and hits the cap 10, where it condenses and then drains into the collection chamber 11. Alternatively, water vapor which does not condense on the cap 10 passes into the collection chamber 11 and condenses on other surfaces of the interior of the collection chamber 11. The condensed, purified water then flows out of the device through water drain 6. In an alternative embodiment, shown in Figure 2, water condenses directly on the upper surface 13 of the chamber housing the central conduit 1 and propellers 12, and/or on screens 24, which are preferably placed within or below the conduit joining the vacuum source (e.g., a fan) 5 and the water collecting chamber 14, in order to catch and retain moisture entering the vacuum fan conduit. Preferably, the vacuum fan 5 is off- set with respect to the opening through which water vapor enters the water collecting chamber 14 of the device. When vaporized water contacts the upper surface 13 of the water collecting chamber 14 and/or the screens 24 , it condenses and then flows down to a lower surface 16 of the collecting chamber 14 and then drains out through the water drain 6. An example of a screen 24 formed from a mesh material is shown in Figure 5. The screens 24 can be made from any material resistant to water and able to withstand the conditions within the present system, and are preferably made from titanium.

As shown in this embodiment, the central conduit 1 is preferably supported by the walls of the tank through the use of support shafts 15 extending from the walls of the tank 2 to one or more support shaft bearings 17 surrounding the exterior of the central conduit 1. Such supports are preferred in view of the high speed of rotation of the central conduit 1. Figure 2 also shows a drive system 20 including an engine or motor and a motor transmission for rotating the central conduit 1. The drive system 20 can directly rotate the central conduit 1 or can rotate the conduit 1 using a belt system. The necessary rotation of the peripheral conduits 3 can also be effected in any other way known to the art.

Definitions

As used herein, the following terms and variations thereof have the meanings given below, unless a different meaning is clearly intended by the context in which such term is used. "Desalinate" and "desalination" refers to the removal of excess salt and other minerals from water.

"Impurities" include molecules dissolved, suspended, or otherwise admixed in a liquid, preferably in water as an aqueous mixture.

"Mineral" refers to a naturally occurring inorganic material with characteristic physical properties and normally having a definite chemical composition.

"Molecules" include elements, compounds, and aggregated materials.

"Nozzle" refers to a mechanical device for directing a fluid flow from a chamber or conduit to the atmosphere.

"Purify" means to remove impurities from and/or decrease the concentration of impurities in a mixture, in particular a liquid mixture such as an aqueous solution.

"Speed of sound" refers to the speed traveled by sound waves in air at ambient conditions. Determining the speed of sound under particular conditions can be accomplished by one of skill in the art.

"Upper" and "lower" are relative terms identifying the location of components of the present device, with "upper" typically denoting a location further from a support surface on which the present device is located, and further from a source of gravity.

"Vaporization" refers to a transition from a liquid state into a gaseous state.

As used herein, the term "comprise" and variations of the term, such as "comprising" and "comprises," are not intended to exclude other additives, components, integers or steps. The terms "a," "an," and "the" and similar referents used herein are to be construed to cover both the singular and the plural unless then- usage in context indicates otherwise.

Example

A device as shown in Figure 2 is constructed, and saltwater from a source of open water is conducted into the central conduit. The device is operated at a temperature of 20 ⁰ C. The central and peripheral conduits are rotated in order to place the nozzles of the device rotating at a speed of between 339 and 347 meters per second (within about 1% of the speed of sound). Water is flowed from the central conduit, into the peripheral conduits, and through the nozzles of the peripheral conduits while the nozzles are being rotated at this speed. *** Although the present invention has been described in considerable detail with reference to certain preferred embodiments, other embodiments are possible. The steps disclosed for the present methods, for example, are not intended to be limiting nor are they intended to indicate that each step is necessarily essential to the method, but instead are exemplary steps only. Therefore, the scope of the appended claims should not be limited to the description of preferred embodiments contained in this disclosure. All references cited herein are incorporated by reference in their entirety.