Patent Abstract:
A fluid tester includes an inlet for a fluid path, an ionization chamber defining at least part of the fluid path located downstream from the inlet, a charge chamber configured to subject a fluid to an electric field defining at least part of the fluid path located downstream of the ionization chamber, a patch holder configured to hold a patch into the fluid path downstream of the electric chamber and an outlet for the fluid path. A method of testing a fluid includes ionizing a fluid, moving particles suspended in the fluid by passing the fluid through an electric field, passing the fluid through a patch and analyzing a patch.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates generally to testing lubricating or hydraulic fluids. More particularly, the present invention relates to a handheld unit for conducting patch tests for analyzing contaminants within lubricating or hydraulic fluids. 
     BACKGROUND OF THE INVENTION 
     Fluids such as hydraulic oil and lubrication fluid are used in a variety of machinery. Because these fluids are used in conjunction with moving parts to reduce the wear on those parts and also remove heat, it is important that these fluids be not contaminated. 
     There are a variety of types of contamination that can occur within lubricating or hydraulic fluid. For example, parts of metal can be worn away from the moving parts and become suspended in the fluid. This is a particularly undesirable situation in that these pieces of metal held in suspension in the fluid can cause additional wear upon parts contacted by the fluid. In addition to suspended particles of metal, lubricating and hydraulic fluid can also become contaminated with water, dirt, organic matter such as bacteria, and other substances that can be found in the system using the lubricating or hydraulic fluid. 
     To allow equipment to operate at optimal efficiency, the lubricating or hydraulic fluid is filtered and regularly changed to avoid allowing contaminated fluid to be used too long in a system. Changing fluid too often or not often enough will result in equipment down time and expense. Therefore, it is desirable to monitor contamination levels within lubricating and hydraulic fluids in order to change the fluid at optimum times. Today, testing lubrication and hydraulic fluids for contamination can, in some instances, require a fluid sample be sent to a laboratory for analysis. This does not allow technicians onsite to quickly identify issues on equipment that is being tested or serviced in the field. Nor does it allow technicians to determine on the spot whether the lubricating and hydraulic fluid needs replacing. 
     There are patch tests currently being used but the patch, itself, is analyzed by a laboratory in yielding the same drawbacks as when the fluid samples themselves are sent for analysis to laboratories. Some on the spot fluid testing may be accomplished by systems in the field using lasers and other expensive technology to analyze the fluid. While these systems may provide on the spot analysis they are prohibitably expensive for many applications. 
     As a result, for many of the above mentioned applications, if not most applications, these sorts of testing units are so expensive or time consuming so as to be not used as effective field testers. Accordingly, it is desirable to provide a method and apparatus that permits field testing of fluids to determine whether the fluid needs to be replaced in a compact, portable, relatively inexpensive, and easy to use way. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect, a method and apparatus is provided that permits field testing of lubricating or hydraulic fluid to determine whether the fluid needs to be replaced in a compact, portable, relatively inexpensive, and easy to use way. 
     In accordance with one embodiment of the present invention, a fluid tester is provided. In some embodiments of the present invention, the fluid tester includes an inlet for a fluid path, an ionization chamber defining at least part of the fluid path located downstream of the inlet, a charge chamber configured to subject a fluid to an electric field defining at least part of the fluid path located downstream of the ionization chamber, a patch holder configured to hold a patch into the fluid path downstream of the charge chamber, and an outlet for the fluid path. 
     In accordance with one embodiment of the present invention, a fluid tester is provided. In some embodiments, the fluid tester includes means for inletting a fluid into a fluid path, means for ionizing fluid located downstream of the inletting means, means for creating an electric field in the fluid path located downstream of the ionizing means, means for holding a patch configured to hold a patch into the fluid path downstream of the means for creating an electric field, and means for outletting fluid from the fluid path. 
     In accordance with another embodiment of the present invention, a method of testing a fluid is provided. In some embodiments, the method includes ionizing a fluid, moving particles suspended in the fluid by passing the fluid through an electric field, passing the fluid through a patch, and analyzing the patch. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view illustrating a handheld fluid testing apparatus according to an embodiment of the invention. 
         FIG. 2  is a top view of a patch that has fluid flown through it in the fluid testing apparatus of  FIG. 1 . 
         FIG. 3  is a top view of a book illustrating what patches will look like when fluids having various characteristics have flow through them in a fluid testing apparatus as shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a fluid tester  10  as shown in  FIG. 1 . The fluid tester  10  is portable and is contained within a case or housing  12 . The housing is equipped with feet  13  which are able to support the weight of the tester  10  when set down on the ground, floor or other object. 
     In some embodiments of the invention, there are four feet  13 . The case  12  in some embodiments of the invention is equipped with a handle  14 . The handle  14  can be fixed or may be pivoted so that it can swing out of the way when not in use. At the top end of the case  12  is an inlet  16 . The inlet  16  is covered with an inlet cap  18 . The inlet cap  18  is removably fixed to the inlet  16 . The inlet cap  18  may be fixed to the inlet  16  by threads, by a snap fit connection or any other suitable way for fixing the inlet cap  18  to the inlet  16 . The inlet  16  exposes a fluid path  20 . The fluid path  20  permits the lubricating or hydraulic fluid to be tested to flow through the tester  10  and provides a path for the fluid to flow in the desired manner. 
     Along the fluid path  20  after the inlet is an ionization chamber  22 . The ionization chamber  22  is configured to ionize the fluid. The fluid may be ionized in the ionization chamber  22  in any suitable manner. In some embodiments of the invention, the ionization of the fluid in the ionization chamber  22  may be accomplished by exposing the fluid to high voltage. In other embodiments, the fluid is exposed to static electric charge or ultraviolet radiation to ionize the fluid in the ionization chamber  22 . 
     After the fluid has flown through the ionization chamber  22  and has been ionized, it continues down the fluid path  20 . In some embodiments of the invention, to facilitate fluid flowing through the fluid path  20 , in the desired direction and at the desired pressure and speed, a pump  24  is used. 
     In some embodiments of the invention, the pump  24  can be an electric pump or can be a hand-operated pump. The pump is sized sufficiently and selected by one skilled in the art to generate enough pressure to flow lubricating or hydraulic fluid, and in instances where a diluting fluid is added to the lubricating or hydraulic fluid, to facilitate the lubricating or hydraulic fluid and solvent fluid combination through the patch  30 . 
     The pump  24  can be placed between the ionization chamber  22  and the charge chamber  28  as illustrated in  FIG. 1 . In other embodiments of the invention, the pump  24  can be placed any where along the fluid path  20  that will provide suitable pressure for allowing the fluid to flow through the fluid path  20 . Still other embodiments may include a tester  10  where the fluid is gravity fed. 
     The charge chamber  28  is equipped with charged walls  26 . The charged walls  26  are in some embodiments negatively charged. In some embodiments of the invention, the walls, themselves, are not charged but the charge chamber  28  is subjected to an electric field. In embodiments where the walls  26  themselves are not charged, the walls  26  form an outer physical boundary to an electric field. 
     In some embodiments of the invention, a charge plate  29  is located on the other side of the path  30  from the main portion  31  of the charge chamber  28 . The charge plate  29  has an opposite charge as the charged walls  26 . As the charge plate  29  is located near the center of the charging chamber  28 , the charge plate  29  will assist in causing charged particles in the fluid to move to either the center of the walls of the charging chamber  28  according to the charge of the particles. 
     The electric field may be provided by a current supplied by a battery located in the tester  10  to the charged walls  26  and the charge plate  29 . In embodiments having negatively charged walls  26  and a positively charged plate  26 , atoms in the fluid that have been positively charged in the ionization chamber  22  will be drawn toward the negatively charged, walls  26  of the electric chamber  28  and vice versa for embodiments having positively charged walls and a negatively charged plate  29 . As mentioned above, the charged walls may not actually be charged but defined an outer edge of an electric field that particles in the fluid can go. 
     Material that is not charged positively or negatively will be located randomly in the fluid in the charge chamber  38 . In embodiments where the walls  26  are negatively charged, any material that is negatively charged will be repelled from the charged walls  26  and attracted to the positively charged charge plate  29  and will have a tendency to move towards the middle of the charge chamber  28 . As the fluid moves through the charge chamber  28  and the particles within the fluid that are positively or negatively charged will be moved to the respective areas as biased by the electrical field within the charge chamber  28 . 
     In addition to charged walls  26 , and a charge plate  29 , to influence particles in the fluid, some embodiments of the invention will also have a magnet  33 . The magnet  33  will in some embodiments, and as shown in  FIG. 1 , be located in the middle of the charge chamber  28  near the charge plate  29  and on the opposite side of the patch  30  from the main portion  31  of the charge chamber  28 . In other embodiments of the invention, the magnet may be located in a position other than near the center as shown and described. The magnet will attract Ferris particles, thereby causing Ferris materials suspended in the fluid to move to where the magnet  33  is. In embodiments where the magnet  33  is located in the center of the charge chamber  28  as shown in  FIG. 1 , the Ferris materials will move toward the center of the charge chamber  28 . 
     After the fluid has flown through the main portion  31  of the charge chamber  28 , it will continue along the fluid path and encounter a patch  30 . The patch  30 , in some embodiments of the invention, is a standard patch used in patch tests for testing lubrication fluids. In some embodiments of the invention, the patch  30  will filter particles five microns in diameter and larger, and will permit particles having a diameter of less than five microns and also fluid to flow through the patch  30 . 
     A patch cover  32  provides access through the case or housing  12  to the patch  30 . The patch can be exchanged once used through the patch cover  32 . The patch  30  when installed in the tester  10  is held securely in place in the fluid path  20 . An old patch that has tested fluid can be removed via the patch cover  32  and a new, fresh patch  30  can be inserted into the fluid path  20  via the patch cover  32  in a suitable manner for conducting the patch test. 
     After the lubricating or hydraulic fluid has flown through the patch  30 , it will continue along the fluid path  20  to an outlet  34 . The outlet  34  is covered by an outlet cover or cap  36 . The outlet cover or cap  36  may be attached to the outlet  34  via threads, snap fit or any suitable method of securing the outlet cap  36  to the outlet  34 . In some embodiments of the invention, the fit between the outlet cap  36  and the outlet  34  seals sufficiently so that lubricating or hydraulic fluid does not leak through the outlet  34  when the outlet cap  36  is in place. 
     In some embodiments of the invention, once the fluid has flown through the fluid path  20  and exited out of the outlet  34 , the fluid path  22  may be cleaned by running a solvent fluid or cleaning fluid through the fluid path  22 . The solvent or cleaning fluid is used to clean out the fluid path  22  and prepare the fluid path  22  for conducting other tests on other fluid. Any suitable cleaning fluid may be used in accordance with the invention including those currently used in current patch tests. 
     In some embodiments of the invention, the lubricating fluid is diluted before flowing through the patch  30 . Diluting the lubricating or hydraulic fluid may be accomplished by adding a diluting agent or solvent to the lubricating or hydraulic fluid. The diluting agent in some embodiments of the invention is the same fluid as the cleaning fluid. Any suitable fluid may be used in accordance with the invention. 
     One reason why the lubricating or hydraulic fluid is diluted is to facilitate movement of particles that are attracted or repelled by the charged walls  26  when otherwise these particles would move extremely slowly due to the thick viscosity of the lubricating or hydraulic fluid. In other embodiments of the invention, adding addition of a dilution fluid to the lubricating or hydraulic fluid is not necessary. In some embodiments of the invention, the diluting agent is added to the lubricating or hydraulic fluid on a 1:1 ratio, or in other words, one ounce of diluting fluid is added for every ounce of lubricating or hydraulic fluid to be tested. 
     In some embodiments of the invention, the tester  10  is configured to permit flow and testing of approximately one half to five ounces of fluid. In other embodiments of the invention, other amounts of fluid can be tested. Dimensions for the tester  10  may be selected by one skilled in the art according to how much fluid is desired to be tested. 
     In some embodiments of the invention, the patch  30 , itself after it has been used to test lubricating fluid, can be cleaned and reused by flowing diluting fluid or solvent through the patch  30  or soaking the patch  30  in a diluting fluid or solvent. In some embodiments of the invention, agitating the patch  30  in the solvent will facilitate in cleaning it and permitting it to be used again. 
     Turning now to  FIG. 2 , a patch  30  that has tested a lubricating or hydraulic fluid is illustrated. A patch  30  that has tested a lubricating or hydraulic fluid will show several regions having different colors. These regions are materials that have been filtered out by the patch  30  in the  FIG. 2 . In a patch  30  that has been used in a tester  10 , as described herein, it is anticipated that at least three regions of different colors will be seen on the patch  30 . In  FIG. 2 , as illustrated, there are three regions  38 ,  40  and  42  illustrated as exemplary. 
     For example, the region identified as  40  in  FIG. 2 , will be concentrated with negatively charged particles. Because the patch  30  is located in a negatively charged chamber  28 , the negatively-charged particles will tend to concentrate towards the center of the magnetization chamber  28 . It is anticipated that the materials concentrating in the center portion of the patch  30  would be negatively charged. These particles include steel, iron, nickel, copper, silicon, dust and dirt because these materials prefer to accept electrons and becoming negatively charged. In addition, in embodiments equipped with a magnet  33  steel, iron and other Ferris materials will tend to concentrate where magnet  33  is located. If there are a lot of copper colored particles this region may appear gold or copper colored. If there are a lot of iron particles, this region may appear dark colored. 
     In the region of the patch  30  identified by reference numeral  42 , it is anticipated that this region  42  will have a higher concentration of materials that tend to become positively charged when subjected to the ionization chamber  22  as described herein. As anticipated, the materials that may tend to concentrate in the regions identified in  42  would include aluminum, lead and other particles that tend to become positively charged when subjected to an ionization chamber  22  as described herein. This region may appear grey or silver colored. 
     These positively charged particles will tend to gravitate in the fluid closest to the proximity to the negatively-charged, walls  26  of the charge chamber  28  because they are positively charged and will be attracted to the negatively charged walls  26 . The materials concentrated in both regions  40  and  42  are wear materials or in other words materials that are suspended in the lubricating fluid because they have worn off in the machinery that is being lubricated by the lubricating fluid. 
     In the region identified in  FIG. 2  as  38 , it is anticipated that here the color of this region would contain materials such as carbon, water, microbes, etc. which do not tend to become positively or negatively charged when subjected to an ionization chamber  22  as described herein. These particles may appear brown or red. Of course, the region  38  would not be the only place where these materials would be found, but they would be found throughout the patch because they are not biased to move towards the outer edge, the center of the patch  30 , or the area in between. 
     Likewise, materials that tend to be concentrated towards the center of the patch in region  40  or the outer periphery of the patch in region  42 , will likewise be typically found in all areas of the patch  30 . However, it is anticipated that due to the charged chamber  28 , materials will tend to concentrate towards either the center of the patch  30 , in the case of negatively-charged materials, or to the outer periphery of the patch  42  in the case of positively-charged materials. 
     In some embodiments of the invention the patch may be analyzed by a microscope. In accordance with the invention the microscope may be a two power microscope. Of course other suitable powered microscope may be used in accordance with the invention. In some embodiments of the invention the microscope is portable and is taken into the field for analyzing the patch  30  when the patch tester  10  is used. 
       FIG. 3  is an illustration of an exemplary guidebook  44 . In some embodiments of the invention, as illustrated in  FIG. 3 , the guidebook  44  can be a spiral-bound book. In other embodiments of the invention, the guidebook  44  can be a fold-out booklet. Other suitable books or booklets may be used in accordance with the invention. 
     The guidebook  44  may have pages  46  with exemplary illustrations  48  of patches  30 . The guidebook  44  can have color or black or white illustrations  48  with different regions a, b and c, identified on the illustrated patches  48 . Other embodiments of the invention include an illustration having more or less regions illustrated on the patches  48 . The guidebook  44  can also contain written descriptions  50  correlating colors or strata regions on the patches  48  with various contaminants in the tested fluid. The guidebook  44  can also include instructions on how to maintain the equipment based on what the tested patch  30  looks like compared to the illustrated pages  48  thus, enabling a user of the tester  10 . In some embodiments of the invention, the guidebook provides illustrated patches  48  that are examples of magnified patches  30  as viewed by a microscope. 
     While the tester  10  has been described as testing a lubricating or hydraulic fluid, it is appreciated that it can be used to test and any number of different fluids. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Technology Classification (CPC): 5