Background Art A typical non-conductive liquid to be cleaned may be an industrial oil such as used for machinery, as an energy transmitter in hydraulic systems, or as an insulator in electrical transformers and other electrical devices. When lubricating and hydraulic oils become contaminated, the particles of dirt cause abrasive wear and fatigue on the machine and ultimately machine failure. When electrical oil becomes contaminated, it no longer acts effectively as an insulator in a transformer. It is normal practice to change oil when it becomes contaminated.

Lubrication and other oils must be maintained as clean as possible to obtain maximum oil and component life. It is generally recognized that the number of particles larger than five microns in one millimeter of lubricating oil must be kept below 150 to maximize component and lubrication oil life.

Particles five microns and smaller have been conclusively shown to be the major cause of abrasive wear and fatigue that leads to component failure. Adequate regular or continuing liquid purification should extend oil life almost indefinitely, eliminate hazardous waste generation and reduce or eliminate equipment wear due to contaminants in the oil.

It has long been known to remove particulate with mechanical filters ; however, these mechanical filters are not effective with particles smaller than 5 microns either because their pore size is too great, or the filter must be large and bulky to avoid an excessive pressure drop within the fluid system.

Electrostatic separation technology has been established as a viable means to better perform cleaning of oils. Electrostatic separation technology is based on passing the oil through an electrostatic field created by a high voltage to electrically charge the particulate matter entrained in the oil. This produces an electrostatic reaction whereupon oppositely charged particles flocculate. The resultant flocculated particles are larger in size than the original constituent particles and are more easily captured. A filter media of a selected pore size and composition may be used to capture and retain these flocculated particles. Thus, particulate matter of submicron size may be extracted from oil, thereby producing oil with a cleanliness level that is unattainable by mechanical filters. The following United States Patents are representative of the prior art for electrostatic fluid filters: 4, 594, 138 611986 Thompson 5,332, 485 7/1994 Thompson 5,571, 399 11/1996 Allen 5, 788, 827 9/1998 Munson While these filters have been designed and are available, most of the devices and apparatus are expensive to construct, bulky or of complicated structure. In addition, the charging and mixing systems are typically rigid canister or housing designs with rigid electrodes used to charge particles as they are swept by. These patents describe fluids which are passed through perforated electrodes which are oppositely polarized by positive and negative charges. The charged particles are collected through mechanical filter media of various shapes and sizes.

Many of the systems using lubricating oil are compact and do not have available space for a bulky, rigid, external cleaning system or space to incorporate rigid canisters or rigid electrodes or mixing chambers. Vehicle lubrication systems where small size and physically conformable systems are required are a primary example.

In addition, many application environments are sensitive to size, weight, on-board mobility, time, temperature and cost.

Accordingly, it is a principal object of the present invention to provide a means of broadening the application areas for electrostatic particulate removal by providing a flexible physically conformable fluid path for both charging and mixing chambers and flexible electrodes and turbulence initiating connector to enhance flocculation of particles.

It is yet another object of the invention to provide a fluid path for charging and mixing which does not require an additional separate external housing or containment vessel.

It is another object of the invention to provide a physically conformable fluid path, flexible electrode and turbulence initiating connector that are economical to construct.

It is yet another object of the invention to provide a simple economical means of passing high voltage wires from the electrodes inside the charging chambers to the power supply outside, while maintaining the continence of the fluid circuit.

Other objects of the present invention, as well as features and advantages thereof, are apparent in, or elucidated in, the following description and appended drawing figures.

Disclosure of Invention The present invention achieves the above objects, among others, by providing, in a preferred embodiment, a controlled, flexible and physically conformable electrostatic cleaning system for removing particulate matter from non-conductive fluid, comprising: at least one pair of flexible and physically conformable charging chambers housing flexible and conformable charging electrodes, connected to a power supply that provides positive and negative electrostatic charging potentials, for the purpose of charging said particulate matter.

Brief Description of the Drawings Understanding of the present invention and the various aspects thereof will be facilitates by reference to the accompanying drawing figures, provided for purposes of illustration only and not intended to define the scope of the invention, in which: Figure 1 shows a schematic of the flexible and conforming non-conductive fluid purification system, with a controlled power supply.

Figure 2A shows a physically conformable version where the flexible tubing, comprising the charging chambers and the mixing chamber, and the flexible electrodes, and the connecting turbulence initiating connector, are configured in a spiral.

Figure 2B shows a cut-away view of a small portion of the flexible tubing that comprises one charging chamber, allowing the flexible electrode and its connection to the high voltage wire to be viewed.

Figure 3A shows a detailed view of the flexible electrode comprised of four wires wound in alternately reverse lay and progressively larger internal and external diameters so as to permit inserting each coiled wire inside the others.

Figure 3B shows a cross-sectioned view of Figure 3A.

Figure 4 is a Table which describes the wire size and physical make-up of the individual coiled wires.

Figure 5A shows a side view of the turbulence-initiating connector.

Figure 5B shows a cross-section of the turbulence-initiating connector configured with the two channels funneling into one and with the high voltage wires exiting from inside the charging chambers to the outside.

Figure 5C shows an end-view of the exit side of the turbulence-initiating connector, with vanes.

Figure 6 is a table presents results of a laboratory test of the present invention.

Best Mode for Carrying Out the Invention Reference should now be made to the drawing figures on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers, when used, direct the reader to the view (s) on which the element (s) being described is (are) best seen, although the element (s) may be seen on other figures also.

Figure 1 illustrates a system diagram of the electrostatic filter of the present invention. An oil inlet 100 is connected to a fluid splitter 101 which splits the fluid into two distinct paths 102 and 103. Charging electrodes 104 and 105 are contained within charging chambers 106 and 107 wherein oil flows past the electrodes.

Particulate in the oil passes the electrodes where a net positive charge is impinged on particulate passing electrode 105 and a net negative charge is impinged on particulate passing electrode 104 through power supplied by power supply 108. Power supply 108 is a source of DC electrical potential. The voltages and currents are controlled, with a voltage in the range of 5000 to 50,000 volts both positive and negative (referenced to earth ground). The two oil paths containing the charged particulate are joined in a turbulence initiator 109. The particulate agglomerates in turbulence initiator 109 and in the mixing chamber 110 to be collected by filter media in the collection filter 111.

Figure 2A illustrates a preferred embodiment of the present invention in a spiral configuration. The entering fluid enters through tube 200 and is split into two paths through the use of a splitter 201. One can also split into multiple pairs of paths.

Splitter 201 incorporates two ports to form a double spiral lead whereby two tubes 203 and 204 create two, high dielectric charging chambers for positive and negative charging of the particulate. The splitter in this embodiment is made from a high dielectric strength material, in this case Teflon, made to withstand temperatures up to 260° C. Electrodes 210 and 211 (Fig. 2B) housed in charging chamber tubes 203 and 204 charge the particulate. Turbulence-inducing connector 205 funnels the two charged streams of particulate into the mixing chamber comprising a tube 208 and provides an egress for high voltage wires 206 and 207, which are connected to the electrodes 210 and 211, from inside the charging chambers to the outside electrical power source (not shown). Mixing chamber (or chambers) 208 is (are) of sufficient length and design to give the charged particles a chance to agglomerate. Figure 2B shows a preferred embodiment of the connection and housing of the electrodes within charging chambers 203 and 204. High voltage wire 206 is coupled to a multitude of wires coiled in the form of interlaced springs, which form the electrodes 210, using a crimped coupler 301. This same embodiment would be duplicated for chamber 204 and the connection of high-voltage wire 207 to electrode 211. It is important to note that this tubing configuration need not be put in a housing such as a canister or box.

The housing for this embodiment is of no consequence and offers tremendous flexibility as to where to place or route the charging and mixing chambers In this embodiment, charging and mixing chambers 203,204, and 208 are constructed from flexible tubing, 1/2 inch outside diameter and 3/8 inch inside diameter Teflon tubing capable of withstanding 600Volts per mil of wall thickness, at a maximum operating temperature of 500 degrees F (260 ° C). The chamber cross- sectional shape could vary from tubular, and its area be greater or smaller depending upon pressure, throughput, geometric conformance or other requirements of the specific application. This tubing has a durometer hardness 55D. This fluorocarbon material will withstand almost all known chemical environments, including vegetable oils, lubricating oils, cutting oils, hydraulic oils, diesel fuels, and others. The described embodiment is not limited to a spiral design and could be easily incorporated into a design requiring the charging and mixing chambers to be straight or"S"shaped or other configurations as long as the minimum bending radius is not violated. The length of charging and mixing chambers 203,204, and 208 are generally related to the rate of flow of fluids through the particular fluid system.

Figure 3A shows the layout of the flexible electrode. The flexible high voltage electrode is comprises wires 401,402, 403 and 404 coiled in the form of helixes, with wire size, spring diameter, pitch, and direction of lay that permits inserting one spring inside another as shown in Figure 3B. The numbers of inter-laced helixes, their materials, and their lengths are determined by the application. In this embodiment, the material is stainless steel. Other appropriate materials are those that are electrical conductors with an affinity for wetting and the ability to retain their helical shape and flexibility. In certain cases, it may be desirable to electroplate or otherwise coat the electrodes with materials that improve their ability to impart a charge.

The interlaced helixes are designed to provide a labyrinth through which the dirty non-conducting fluid flows while destroying laminar flow. As the fluid traverses the labyrinth, it encounters springs 401,402, 403 and 404 and is forced around the wires at an accelerated rate. The particulate that cannot negotiate the direction change are propelled into the high voltage electrode thereby picking up a charge. Those particles that manage to go around the first barrier are also accelerated and directed towards and collide with the next wire, and so on, causing more and more dirt particles to be effectively and efficiently charged along the length of the electrode.

As the manufacturing technology of spring winding is highly advanced, the resulting interlaced, flexible, highly efficient high voltage electrode is significantly low in cost, easy to design, and readily available. The interlaced springs are easily assembled, and allow easy bending to conform to the geometric design. In this embodiment, the electrodes are laid in tubing configuring the electrode in a spiral pattern. The electrode may be laid straight or in an"S"configuration or other configurations as well.

In this embodiment, the electrode comprises four interlaced springs, 401,402, 403 and 404. The spring material is stainless steel, with equal wire diameters of. 025 inches. Wire 401 is wound in a right hand lay with a pitch of 30.3 coils per inch..

This results in an inside diameter of 0.075 inches and an outside diameter of 0. 125 inches. Wire 402 is wound in a left hand lay with a pitch of 19.2 coils per inch, providing an inside diameter of 0. 138 inches and outside diameter of 0.188 inches.

Coiled wire 401 can be readily inserted into coiled wire 402 leaving a space of 0.0065 inches per side between the two, and more varied labyrinth because of the oppositely wound lays and different pitches as shown in Figure 3B. This continues in like fashion for wires 403 and 404, where the outside diameter of wound coil 404 of 0.313 inches fits into the Teflon tubing with an inside diameter of 0.375 inches. In its coiled spring configuration, the electrode is able to flex and conform to any shape the flexible charging chamber assumes.

Figure 4 indicates the lay, wire size, coil OD and coils-per-inch for this embodiment. The number of coils, length, wire size and coil OD can vary depending on the cleaning application. A larger capacity system may require more coils and longer length.

Figure 5A is a side view of the turbulence inducing connector 205. This connector is designed to collect the fluids from the two charging chambers 203 and 204 (Fig. 1), initiate a swirling turbulent action and funnel the two swirling streams into the single mixing chamber 110 (Fig. 1). Figure 5B shows a cross-sectional view of the turbulence inducing connector 205. For this embodiment in Figure 5B, inlet ports 203 and 204 containing oppositely charged particles mate with the turbulence- inducing connector 205 at entrance ports 501 and 502. Entrances to the internal swirling chamber 505 is achieved through port openings 503 and 504. The resultant mixed fluid exits through port 506 and subsequently to a main mixing chamber, tube 208. Figure 5C shows an end view of the turbulence inducing-connector 205. The connector incorporates two small channels 513 and 514 passing through the wall of the connector through which high voltage wires 206 and 207 can intersect and pass through the swirling chamber 505 into ports 501 and 502 and be connected to the flexible electrodes 210 and 211 (Fig 2A). This action serves to reduce the length of the main mixing chamber and the time required for the opposite charges to encounter each other and agglomerate. In addition, the connector is designed to permit easy exiting of the two opposite voltage high voltage wires from inside the charging chambers to the outside.

In this embodiment, the turbulence inducing connector 205 is made of Teflon with an electrical dielectric strength of 600 volts per mil and operating temperature of 400 degrees F (260C). Entrance ports 501 and 502, are narrowed at entrances 503 and 504 to the small internal swirling chamber 505 of connector 205 in order to speed up the entrance velocity of the two streams of fluid and to create a stop for the tubing so as not to encroach on the internal swirling chamber. Exit port 506 is likewise reduced so as to create a stop 507 for the tubing, to create an even larger back pressure in the internal swirling chamber than already present, and to increase the turbulent velocity down the flexible main mixing chamber 208. The turbulence initiating connector 205 is curved in this embodiment to replicate the conformance of this particular spiral configuration, but could easily be rectangular, cylindrical, or of a complex shape that could be used to conform to a particular locating geometry, thus the turbulence-inducing connector is able to be machined or molded to take on a variety of exterior shapes to match the needs of the available space.. The entrance and exit ports have a 2: 1 area (from 0.221 to 0110 square inches) creating a large back-pressure which in turn initiates a violent turbulent swirling as the fluid and particulate merge, collide, and then exit down the main flexible mixing chamber 208 at a high velocity. This high velocity swirling turbulence down the main mixing chamber provides many more occasions for the oppositely charged particulate to meet and agglomerate in a minimum of distance.

The subsequent flocculated particles and fluid pass from the mixing chamber 208 to a collection filter (not shown). The collection filter can be widely varied as needed for a particular application. The collection filter is typically constructed of reticulated foam or other suitable material having communicating pores throughout. The collection filter can be, but need not be incorporated into the same tube as the mixing chamber 208 and can itself be physically conformable.

High voltage wires 206 and 207 are routed inside charging chamber tubes 511 and 512 and into charging tubes 203 and 204. The connector provides easy access to the outside by passing through ports 513 and 514 that are sized to constrain the high voltage wires and provide an easy means of bonding them in place with epoxy or other non-conductive adhesive.

Figure 6 shows data from a laboratory test using the charging and mixing system of the present invention. Figure 6 is a table of time versus particle count versus particle size (as used to clean transformer oil, a particularly difficult medium to clean). In a 72 hour test, large size particulate greater than 30 microns were eliminated and smaller particulate greater than 2 microns was dramatically reduced by 92%.

In the embodiments of the present invention described above, it will be recognized that individual elements and/or features thereof are not necessarily limited to a particular embodiment but, where applicable, are interchangeable and can be used in any selected embodiment even though such may not be specifically shown.

Terms such as"above","below","upper","lower","inner","outer","inwardly" , "outwardly","vertical","horizontal", and the like, when used herein, refer to the positions of the respective elements shown on the accompanying drawing figures and the present invention is not necessarily limited to such positions.

It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.