Hydrocyclone and method to remove particles from liquid streams

This invention is directed to a hydrocyclone that will separate particles from a liquid stream, such as from an irrigation water stream for use in drip irrigation. The invented hydrocyclone has an inlet, a separation section, a clean liquid outlet, and a slurry outlet, wherein the separation section has a vortex and a cone, and wherein the vortex length is more than three times longer than the cone length, and the cone has an angle of about 45 degrees. The invented hydrocyclone also has a vortex diameter to vortex length ratio of between about 0.8 and about 1.2, and a cone length to vortex length ratio of between about 0.28 and about 0.35. The invented hydrocylone may be of unitary construction. When in use, the invented hydrocyclone may create a clean water stream having at least 78% fewer particles than the original liquid stream.

BACKGROUND

1. Field of the Invention

The invention is directed to hydrocyclones that separate particles from the liquid streams that carry them, such as from water streams used for drip irrigation.

2. Related Prior Art

Drip irrigation is a very efficient method of applying water and nutrients to crops. Lower-volume water sources can be used because drip irrigation may require less than half of the water needed for sprinkler or flood irrigation. Lower operating pressures mean reduced energy costs for pumping. High levels of water-use efficiency are achieved because plants can be supplied with more precise amounts of water. A drip irrigation system has three different pipelines: (1) mainline to convey water from main source, (2) sub-mainline (or header) to convey water from mainline, and (3) drip lines that connect to the sub-mainlines to deliver water through emitters to where the water is needed.

A. Methods and Devices to Keep Debris Out of Drip Irrigation Systems

Drip irrigation systems must deliver water through the pipelines to plants. Therefore, debris that may clog the lines must be kept out of the drip irrigation system or the plants will not receive the adequate amount of water. The particles that are found in irrigation streams can be heavier than water-particles having a specific gravity greater than 1.0. Particles found in an irrigation stream can also be lighter than water-particles having a specific gravity less than 1.0. Also, particles come in different sizes, with some being smaller than others.

There are different methods and devices to keep debris and particles out of the drip irrigation system, particularly out of the drip lines. Each different method and device is optimized to separate out particles of certain sizes or certain specific gravities from the liquid stream. Some techniques and devices to keep debris and particles out of the drip irrigation system include: media filters, sand separators, screen filters, and disk filters.

Media filters are the most common filters used in commercial vegetable production. Media filters filter out particles by size. Ranging from 14 inches to 48 inches in diameter, they are usually installed in pairs. Media filters are expensive, heavy, and large, but they can clean poor-quality water at high flow rates. As the media fills with particulate matter, the pressure drop across the media tank increases, forcing water through smaller and fewer channels. This will eventually disable a media filter, requiring that clean water from one tank be routed backwards through the dirty tank to clean the media.

Like media filters, screen filters are used widely in commercial vegetable production and filter particles by size. Screen filters are the most common irrigation filter used by small operations if the water source is relatively clean. Screen filters can remove debris efficiently like a media filter, but they are not capable of removing as much debris as a media filter before cleaning is required. Compared to media filters, screen filters are often oversized because they only have a relatively small, two-dimensional cleaning surface. Regular cleaning of screen filters is very important. If they are neglected, a portion of the screening element will become caked and clogged, forcing water through a smaller area, pushing debris through the screening element and at ever increasing energy losses—under extreme conditions—rupturing it.

Disk filters are devices that possess traits of both media and screen filters. Disk filters also filter particles by size. The screening element of a disk filter consists of stacks of thin, doughnut-shaped, grooved disks. The stack of disks forms a cylinder where water moves from the outside of the cylinder to its core. Like a media filter, the action of the disk filter is three dimensional. Debris is trapped on the cylinder's surface while also moving a short distance into the cylinder, increasing the capacity of the disk filter. Cleaning a disk filter requires removing the disk cylinder, expanding the cylinder stack to loosen the disks, and using pressurized water to spray the disks clean. Although disk filters have a cleaning capacity between media and screen filters, disk filters are not recommended where organic matter or sand load is high.

Unlike filters, sand separators separate particulate matter by specific gravity by swirling the incoming liquid stream through a vortex and separating out the particles from the water. Sand separators must be sized according to the flow rate to operate properly.

Like a sand separator, a hydrocyclone device separates out debris and particles from a liquid stream on the basis of specific gravity. A hydrocyclone is a device that classifies and separates particles suspended in liquid based on the ratio of their centrifugal force to fluid resistance. This ratio is high for high specific gravity and coarse particles, and low for low specific gravity and fine particles. A hydrocyclone will normally have a cylindrical section at the top where liquid is being fed tangentially, and a conical base. Current hydrocyclones collect particles in the conical base, requiring regular cleaning to keep the hydrocyclone functioning effectively.

What is needed is an effective method and device to keep drip irrigation systems clear of debris requiring little maintenance and little energy.

SUMMARY

This invention is directed to a hydrocyclone for separating particles from a liquid stream, comprising an inlet, a vortex having a length, a cone having a length and an angle, a clean liquid outlet, and a slurry outlet, wherein the vortex length is more than three times longer than the cone length, and the cone angle is about 45 degrees. The hydrocyclone may be of unitary construction.

In another aspect, the invention is directed to a method of separating particles from a liquid stream comprising: creating a hydrocyclone having an inlet, a separation section, a clean liquid outlet, and a slurry outlet, wherein the separation section has a vortex having a length and a cone having a length, and wherein the vortex length is longer than the cone length; creating a pressure within the separation section; directing a stream of liquid into the inlet; ensuring the liquid stream is circulated through the separation section, wherein the liquid stream is separated into a clean stream and a slurry stream by the pressure; guiding the clean stream towards and out of the clean liquid outlet; and disposing the slurry stream out of the slurry outlet.

The separation section in the method described above may further comprise a clean liquid separation zone, and a slurry separation zone. The vortex may have a diameter and a length, and the ratio of the vortex diameter to the vortex length may be between about 0.8 and about 1.2. The vortex may have a vortex arm having a length and a vortex base having a length, and the ratio of the arm length to the base length may be between about 2 and about 4. The cone in the method described above may be angled between about 45 degrees and about 50 degrees. The ratio of the cone length to the vortex length may be between about 0.28 and about 0.35. The cone may have a wide diameter, and the ratio of the wide diameter to the cone length may be between about 3.1 and about 3.2.

In another aspect of the invented method, the stream of liquid has a first particle amount, and the clean stream has a second particle amount, and the second particle amount is at least 78% less than the first particle amount.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Irrigation streams in the Central California agriculture areas often have dust particles and other particles in water streams. These dust particles and other particles are very difficult to separate out from water streams. This can cause the water used for irrigation, industry, and swimming pools to contain unwanted particles. One purpose of the invented micro cyclone, or hydrocyclone, is to remove these dust particles—as well as any larger particles—out of water streams so the water used for irrigation, industry and swimming pools can be cleaner. In one embodiment, the invented hydrocyclone separates particles from water streams so that irrigation drip lines do not get clogged during usage.

A. Design of Invented Hydrocyclone

As shown inFIG. 1, the invented hydrocyclone10has outer cylindrical body12, inlet50, clean liquid outlet60, and slurry outlet70. Hydrocyclone10has front surface13and back surface14. Hydrocyclone10is divided into different sections: vortex20, cone30, and slurry separation zone40. Together, vortex20and cone30form separation zone36. Inlet50has inlet opening51to receive an incoming liquid stream, inlet body portion52, and inlet connection53to connect to separation zone36. In one embodiment, inlet connection53connects to vortex20. Clean liquid outlet60has outlet opening61to release the processed water, outlet body portion62, and outlet connection63to connect to front surface13. Slurry outlet70is located on back surface14, and releases the particles, sediment, and dust that are separated away from the clean liquid.

As shown inFIG. 2, hydrocyclone10has many sections, all with precise dimensions to effectively filter out particles, sediment, and dust from the liquid stream. Separation zone36is made up of two distinct sections: vortex20and cone30. Vortex20has vortex length21and vortex diameter22. In one embodiment, vortex length21may be between about 1.2 inches and about 1.5 inches, and may be specifically about 1.364 inches. Vortex diameter22may be between about 1.32 inches and about 1.42 inches, and may be specifically about 1.375 inches. Ratio of vortex diameter22to vortex length21may be between about 0.8 and about 1.2, more specifically may be between about 0.9 and 1.1, and may be most specifically about 1.

Also shown inFIG. 2, vortex20has vortex arm23and vortex base25. Vortex arm23may have arm length27, and vortex base may have base length28. Arm length27may be between about 0.9 inches and about 1.2 inches, and may be specifically about 0.989 inches. Base length28may be between about 0.3 inches and about 0.4 inches, and may be specifically about 0.375 inches. The ratio of arm length27to base length28may be between about 1 and about 5, more specifically may be between about 2 and 4, and most specifically may be about 2.6. The sum of arm length27and base length28should equal vortex length21.

Clean separation zone17is situated in the middle of vortex20, but physically separated from vortex arm23by separation barrier26. Clean separation zone17has clean separation length18and clean separation diameter19. In one embodiment, clean separation length18may be between about 0.8 inches and about 1.2 inches, and may be specifically about 0.989 inches. Clean separation diameter19may be between about 0.3 inches and about 0.4 inches, and may be specifically about 0.375 inches. Clean separation zone17leads into clean liquid outlet60, up outlet body62, along outlet length64, out outlet opening61.

Continuing withFIG. 2, cone30has cone length31, cone wide diameter32, and cone narrow diameter35. Cone30forms angle45with respect to outer cylindrical body12. Angle45may be between about 40 degrees and about 50 degrees, and may be specifically about 45 degrees. In one embodiment, cone length31may be between about 0.4 inches and about 0.5 inches, and may be specifically about 0.438 inches. Cone wide diameter32may be between about 1.32 inches and about 1.42 inches, and may be specifically 1.375 inches. Cone narrow diameter35may be between about 0.4 inches and about 0.6 inches, and may be specifically about 0.5 inches. The diameter of cone wide diameter32to cone length31may be between 3.1 and 3.2, and may be specifically about 3.14.

Still continuing withFIG. 2, hydrocyclone10can be made of unitary construction by being printed from a three-dimensional printer, such as a PolyJet 3D printer, or may be cast as a unitary piece from a mold. PolyJet 3D printing is similar to inkjet printing, but instead of jetting drops of ink onto paper, PolyJet 3D Printers jet layers of curable liquid photopolymer onto a build tray. The process can be described in these three steps:

(1) Pre-processing—Build-preparation software automatically calculates the placement of photopolymers and support material from a 3D CAD file.

(2) Production—The 3D printer jets and instantly UV-cures tiny droplets of liquid photopolymer. Fine layers accumulate on the build tray to create a precise 3D model or part. Where overhangs or complex shapes require support, the 3D printer jets a removable gel-like support material.
(3) Support removal: The user easily removes the support materials by hand or with water. Models and parts are ready to handle and use right out of the 3D printer, with no post-curing needed.

As shown inFIG. 1andFIG. 2, hydrocyclone10has outer cylindrical surface12, outer wall16, front wall15, inlet50, and clean liquid outlet60. Flanges48define cone30, slurry separation zone40, and slurry outlet70. In one embodiment, front wall15may measure between about 0.05 inches and 0.2 inches in thickness, and may measure specifically 0.136 inches in thickness. Outer wall16may measure between about 0.05 inches and 0.2 inches in thickness, and may measure specifically 0.136 inches in thickness. Separation barrier26may measure between about 0.05 inches and 0.2 inches in thickness, and may measure specifically 0.136 inches in thickness. In one embodiment, clean liquid outlet60may have a wall that measures the same thickness as separation barrier26. Clean liquid outlet60connects to clean separation zone17by outlet connection63, located on front surface13.

As shown inFIGS. 2 and 3, inlet50connects to separation zone36, specifically inlet50connects to vortex20via inlet connection53. Inlet50has inlet length54—as measured from inlet opening51to center of the axis of vortex20—and inlet diameter59. As shown inFIG. 3, inlet50can be situated to connect to vortex20such that the incoming liquid stream200circles clockwise through vortex20, around and along vortex arm23, directed by vortex surface24. In one embodiment, inlet length54may be between about 1.55 inches and about 1.75 inches, and may be specifically about 1.625 inches. Inlet diameter59may be between about 0.4 inches and about 0.6 inches, and may be specifically about 0.5 inches.

B. Method of Separating Particles from Liquid Stream Using Invented Hydrocyclone

As shown inFIGS. 1-4, hydrocyclone10may be used to separate particles from a liquid stream by connecting a liquid supply line to inlet50, and by connecting an emitter to slurry outlet40. The liquid supply line delivers a supply of pressurized liquid to be processed through hydrocyclone10. The liquid supply line must be pressurized to force the liquid through hydrocyclone10. Together, emitter coupling tube5along with emitter4exert a pressure—referred to in the art as “back pressure”—on the liquid stream within hydrocyclone10, and regulates the flow rate of the disposed slurry stream. Together, the liquid supply line and the emitter create a back pressure within separation section36. As shown inFIG. 4, the flow rate through hydrocyclone10is determined by the hydraulic properties and number of emitters connected to drip streams201on drip line3. The flow rate described above determines the separation efficiency of hydrocyclone10.

An emitter is broadly described as any device that creates a controlled and predictable flow. In one embodiment, the emitter may be a slurry line emitter from OreMax, and may be a 1 gallon per hour emitter. The continuously purging flow created by the emitter is determined by the emitter design.

As shown inFIG. 1andFIG. 4, inlet50may be connected and secured to sub-main line2, such as a layflat supply manifold, such as a Cobco Poly-Piple lay-flat flexible tubing. In one embodiment, sub-main line2may fit over inlet50, and a clamp may hold sub-main line1securely in place on inlet50. Sub-main line2delivers pressurized liquid stream100, such as an irrigation water stream, into separation zone36. Drip line3may be connected to and secured to clean liquid outlet60. In one embodiment, drip line3may be from DripWorks, and may be a polyethylene tubing measuring either 0.25 inches in diameter, or 0.5 inches in diameter. In one embodiment, drip line3may fit over clean liquid outlet60, and a clamp may hold drip line3securely in place on clean liquid outlet60. Clean stream200may then be diverted into drip streams201to be dispensed to plants. In one embodiment, drip streams201may be dispensed through emitters, such as Jain Button Emitters.

Also as shown inFIGS. 2 and 4, slurry outlet70may be connected and secured to emitter4. In one embodiment, emitter coupling tube5may be inserted into slurry separation zone40, and the emitter coupling tube5may be screwed to emitter4. Slurry stream300exits slurry separation zone40out of slurry outlet70and enters into, passes through, and exits emitter4. Emitter4works with sub-main line2to create back pressure within hydroclone10.

As shown inFIGS. 1 and 4, a liquid stream100is delivered by sub-main line2into hydrocyclone10through inlet50, specifically through inlet opening51, and is directed along inlet body portion52into separation zone36, first through vortex20and then through cone30. When hydrocyclone10is in use, liquid stream100is directed through vortex20and cone30and separated into clean stream200and slurry stream300. Clean stream200exits clean liquid outlet60along outlet body portion62and out outlet opening61. Slurry stream300exits slurry outlet70. Clean stream200is delivered to drip line3and subsequently to drip streams201, which each may be controlled by a drip line emitter. The number of drip line emitters controlling drip streams201automatically fixes the flow rate critical to achieving maximum separation efficiency from hydrocyclone10.

As shown inFIGS. 2 and 3, vortex surface24directs liquid stream100in a circular pattern along vortex arm23. Once in vortex20, irrigation stream100is directed by vortex surface24and separation barrier25in a clockwise direction around vortex arm23, down to vortex base25. The circular pattern of the liquid stream within vortex20creates centrifugal force on liquid stream100, thereby forcing the particles, sediment and dust outwardly toward vortex surface24. Unlike the particles, sediment and dust forced outwardly by the created centrifugal force, the liquid containing fewer particles, sediment and dust remains closer to the axis of vortex20. At vortex base25, the pressure created by sub-main line2and emitter4within hydrocyclone10forces the liquid containing fewer particles, sediment and dust from an area of higher pressure—vortex base25—into an area of lower pressure—clean separation zone17. The liquid forced into clean separation zone17is defined as clean stream200.

Continuing withFIGS. 2 and 3, once in vortex base25, the particles, sediment and dust forced by centrifugal force outwardly towards vortex surface24will continue to travel along vortex surface24towards cone30. Once within cone30, cone surface34guides the particles, sediment and dust toward slurry separation zone40. Once in slurry separation zone40, the particles, sediment and dust become slurry stream300. Slurry stream300progresses from slurry separation zone40and out slurry outlet70, guided by slurry zone surface44. Slurry stream300exits hydrocyclone10out of slurry outlet70and into emitter4. Slurry stream300eventually also exits emitter4.

Slurry separation zone40is situated between cone30and slurry outlet70. The role of slurry separation zone40is to sequester the separated particles, sediment and dust in a sheltered location so the transient turbulence does not lift them back into vortex base25and deliver them to clean separation zone17.

Also as shown inFIG. 4, slurry stream300may be dispensed by slurry outlet70into emitter4. Ultimately slurry stream300will be disposed out of emitter4and in the field.

Example 1: Hydrocyclone is Effective at Removing Small Particles from Irrigation Water

For the hydrocyclone10assembly in this example, the sub-main line2connection was Cobco Poly-Pipe lay-flat flexible polyethylene tubing measuring 0.5 inch in diameter. Also, emitter4was an OreMax 1.0 gallon per hour emitter. The emitter coupling tube5was Cobco Poly-Pipe lay-flat flexible polyethylene tubing measuring 0.5 inch in diameter. The sub-main line2was pressurized at a range of about 20 psi to about 25 psi. The emitter4was set to create a continuously purging flow at 1.0 gal/hour.

Drip line3was connected to and secured to clean liquid outlet60with a clamp. Drip line3was polyethylene tubing measuring 0.25 inches in diameter, manufactured by DripWorks. Clean stream200was delivered into drip line3and out of drip streams201to be dispensed to plants. Drip streams201was dispensed through button emitters, manufactured by Jain Irrigation. In this embodiment, there were 360 Jain button emitters (set at a flow rate of ½ gallon per hour) connected to drip line3.

Liquid stream100was injected by the sub-main line2into inlet50at a flow rate of 3.0 gal/min. Liquid stream100contained silica sand weighing about 4.000 grams, and measuring between 58 microns and 75 microns. The clean stream200that was collected from clean liquid outlet60was ejected at a flow rate of 3.0 gal/min. The slurry stream300that was collected from slurry outlet70was ejected out of slurry outlet70at a flow rate of 1.0 gal/hr. The slurry stream contained silica sand weighing about 3.132 grams, and measuring between 58 microns and 75 microns.

Hydrocyclone10as described in the figures and specification of this patent application is effective at separating out 78.3% of particles measuring between 58 microns and 75 microns from liquid streams.