EPK- EasyTest Patch Test Kit Manual The new Patch Test Kit from Schroeder provides the necessary tools to determine levels of both water and solid particulate contamination present in a particular fluid sample. Using the vacuum pump contained in the kit, the fluid sample is drawn through a membrane patch. The residual dirt left on the patch is viewed under a microscope and compared to photos of known contamination levels in the Schroeder Contamination Handbook (included) for a visual assessment. L-285
Table of Contents Introduction... 3 Getting Started... 3 Kit Components... 3-4 Replacement Parts... 4 Obtaining Fluid Samples... 4 Patch Test Instructions... 5-6 Crackle Test Instructions... 7-8 Using a Pocket Viscosity Comparator 8- After the sample has been taken... 2 Troubleshooting Guide... 2 Sampling Procedures Appendix A: How to Take an Oil Sample Through a SchroederCheck Test Point Kit Components... 3 Appendix B: Recommended Practices For Taking Oil Samples From A Hydraulic Reservoir... 4 Page 2 of 4
The EasyTest Patch Test Kit (EPK) from Schroeder is designed to enable you to:. Perform visual evaluation of the solid particulate contamination level of a fluid sample in the field 2. Identify specific contaminants present in the fluid 3. Determine the amount of water present in the fluid sample Instructions for items & 2 are covered in this manual with references to the Schroeder Contamination Handbook, L-27, a full color booklet containing photos of various samples, also enclosed. Instructions for item 3 above are included as a separate manual entitled EWC: Operating and Maintenance Instructions, L-2694, also enclosed in this kit. All three documents should always remain with the kit. Getting Started The components enclosed in the kit are described in Figure. A list of their part numbers appears in Table, and a list of replacement part numbers is listed in Table 2. Figure EPK-0 Vacuum Pump and stand LF-7728 Sample Bottles EPK-6 0.8 µm filter patches EPK-20 Fluid patch holder EPK-08 Microscope, 00X EPK-4 Funnel High Intensity Lamp EPK-04 Solvent Filter Bottle Pocket Viscosity Comparator Tools for Crackle Test Page 3 of 4
Table : Kit as supplied includes: Quantity Description Quantity Description High Intensity Krypton Lamp w/ 9" Neck 4 20cc Plastic Sample Bottles 50 Viscosity Meter (200-400 cst) Battery Powered Soldering Iron 4.5" Stainless Steel Forceps 8-Micron Membrane Patches 50.5 Dia., 2 Mil., Adhesive Coverslips Case with foam insert Contamination handbook Instruction manual 50 3"x5" Sample Prep Cards 480 ml Waste Bottle - Threads Onto Vacuum Pump 00X Microscope Plastic Funnel Vacuum Pump w/ Folding Stand Solvent Dispenser Bottle Table 2: Replacement Parts: Part No. LF-7728 EPK-32 Plastic sample bottle Description 50, 8-Micron Membrane Patches EPK-39 50,.5" Dia., 2 Mil., Adhesive Coverslips Obtaining Fluid Samples To ensure that your samples are representative of the hydraulic system s current state of contamination, make sure that: samples are taken at system operating temperature turbulent conditions exist at sampling point sample is taken while the system is operating or immediately after it is shut down Refer to Appendix A for instructions on how to take an oil sample through a test point. Refer to Appendix B for instructions on how to take an oil sample from a reservoir. Page 4 of 4
Patch Test Instructions Reference the photo in Figure (page 3) for all part number designations: ) Remove EPK-0, vacuum pump, and install stand. 2) Remove EPK-4 funnel 3) Grip the top and bottom part of the funnel and pull the stem. This will cause the funnel to separate into two pieces. 4) Install the stem of the funnel into the vacuum pump and tighten the nut on the vacuum pump. 5) Using the tweezers provided, place a fluid patch (EPK-32) into the base of the funnel stem. Place the top part of the funnel back onto the stem that is now in the vacuum pump. 6) After aggressively agitating the sample, open the sample bottle and pour the sample into the funnel until it covers the first line; this represents approximately 28 ml. This is the line that is closest to the bottom of the funnel. This oil volume matches the Contamination Handbook patch photo examples, and allows enough remaining oil to send the bottle sample into either Schroeder s Lab or a lab of your choice. 7) Once this is done, pump the vacuum handle until all the fluid is pulled through the patch. 8) After the fluid has been pulled through the patch, take the solvent bottle and squirt solvent around the edges of the funnel. This will wash any contaminates that were stuck on the funnel onto the patch. Page 5 of 4
9) Remove the top part of the funnel. 0) Using the tweezers, remove the dirty patch and place it in one of the EPK-20 containers, leave the lid off of the container. ) Turn on the flashlight and insert it into the bracket attached to the microscope. Remove the glass plate on the bottom of the microscope. Place the microscope onto the plastic container and adjust the microscope until the contaminates become clear. Once you have focused in on the patch surface, scan the surface for debris left from pulling the oil through, move the patch around on the slide using the tweezers and find an overall average representation of the debris or patch cleanliness. (each view with the microscope is about /64 of the patches surface area) Now use the Contamination Handbook to determine the Estimated ISO Cleanliness Code. 2) Install the top part of the funnel back onto the stem and rinse the funnel with solvent so it will be clean for the next use. Page 6 of 4
Crackle Test Instructions Container in which oil sample can be vigorously agitated to ensure sample suspension Material Needed Caution Inspection Procedure Look for Hotplate capable of maintaining 60C Glass tube (to act as a pipette) or eyedropper Or Industrial soldering iron Glass test tube or small vial BE AWARE of the flash point of the lubricant you are testing, and the temperature of the hotplate or soldering iron used to conduct the test (check with the handheld infrared temperature gun). Ensure the temperature of the heat source is kept between 55 and 60C. Higher temperature could cause violent bubbling and splattering, and excessive heat could cause ignition. Vigorously shake the oil sample to ensure suspension of all material within the sample. o If you are unable to manually agitate the sample adequately, a shaker device (i.e., canister paint shaker) or blender can be used, however, you must ensure the testing procedure does not introduce water into the sample! If using hotplate, use the pipette/tube and allow two small drops to fall on the middle surface of the hotplate (only a few seconds are required). If using soldering iron method, tilt the sample tube/bottle about 45 degree angle, and insert the tip of the iron into the oil sample (only a few seconds required). o In the hotplate method o IF water is present: Using sharp ears, you will hear a small crackling noise (thus, the name, crackle test ), and may see small bubbles appear and explode as the water vaporizes and escapes. Very small (barely distinguishable) bubbles occur across the whole sample, water content up to approximately 0.% is suspected. Note that heating the oil samples will cause the bubbles to form and eventually no more bubbling will occur, as the water will have completely vaporized and remove itself from the oil sample rather quickly. If bubbles tend to form toward the center of the bubble, enlarge and then disappear, water content between 0. and 0.2 percent is suspected. If bubbles form and expand, then collapse, and continuing one or two (or more) cycles, greater than 0.2 percent water contamination is indicated. At this point, the crackling sound is often audible. Page 7 of 4
Look for o o o IF water (free or emulsified) is not present, then the sample bubble will remain intact and slowly start to spread across the plate. If no bubbles appear within a few seconds, clean the hot plate. No detectable water is present. If soldering iron method is used: Insertion of the hot tip of the soldering iron into the sample bottle or tube will yield similar results to the hotplate method, however, bubbling may occur in the tube oil volume and hug the soldering iron surface and boil to the top. The vaporization of the water will most likely happen quickly, and may be more audible if a sample tube is used rather than a small sample bottle. NOTE Consider & Recommend Remember the crackle test is not a quantitative test it is a DETECTION process. o Inform the Customer. o Send a full sample to a professional laboratory to determine water content and potential metals oxides content. o Attempt to determine water contamination source. These may include o Vent cover detached o Seal leakage o Cooling water jacket leakage o Submersion/flooding (constant or intermittent) of machinery or unsecured piping o Condensation o Overspray o Filter leakage o Expansion/contraction which changes seal tolerance Other sources of water ingress Using a Pocket Viscosity Comparator Viscosity is a measure of the resistance of a fluid to deformation under shear stress. It is commonly perceived as "thickness", or resistance to pouring. In bearings, viscosity of the lubricant determines the ability of the lubricant to support the rolling elements and remove heat at speed. Viscosity is one of the most important factors of lubrication. A change in viscosity can be caused by a change in oxidation characteristics, excessive mechanical stress, and/or contamination. If oil viscosity increases or decreases by 20%, a problem is indicated and should be investigated! The principle of operation is simple. It is based on comparing the viscosity of a sample of oil with oil of known viscosity. The viscosity reading is made directly in Centistokes. No calculations are necessary. An accuracy of 95percent or better is easily achieved when making tests. Careful operators can obtain excellent results. The VISGAGE is more widely used throughout the world than any other type of viscometer, for two very good reasons, better accuracy and easier operation. Operators in the field can consistently test as accurately and faster than most commercial laboratories. For the purpose of this instruction, the terms viscosity comparator and visgage will be used interchangeably. Page 8 of 4
HOW TO FILL THE TEST TUBE: CAUTION: Do not draw hot oils directly from a crankcase or reservoir into the VISGAGE.Place a small quantity of oil into a container (Fig. I), then insert nozzle of VISGAGE into this oil (fluid) when temperature is approximately 27C (80F). Best test results are achieved when tests are made at 27C (80 F). After inserting nozzle in oil to be tested, slowly withdraw plunger (Fig. I). If an air bubble appears in the test tube, invert the VISGAGE (Fig. 2) and discharge the air with a small amount of oil. Insert nozzle in oil, slowly withdraw the plunger and completely fill the test tube with oil, free of air bubbles. HOW TO PLACE VISGAGE IN DRAFT PROOF CASE: Adjust the plunger to set sphere in test tube to zero (Fig. 3). Position VISGAGE in draft-proof case with plunger rod extending through slot at right side of case (Fig. 4). Close and lock cover. Allow the oils to attain the same temperature. READING: Hold the case with VISGAGE in horizontal position at eye level, fifteen inches away, with scale in upright position. With both spheres on zero line, tilt instrument with nozzle end down (Fig. 5) to an angle between 30 and 45 degrees so spheres move through the oils toward the line at left side of scale. (To develop your proficiency, make VISGAGE tests using a standard fluid of specific viscosity for determining best angle of tilt.) Give spheres the run of the oils. As the leading sphere approaches the line (38.6 line/76.5 line) at left of scale, gradually move the instrument to horizontal position to stop leading sphere exactly on the line. Read point on scale opposite position of other sphere. The reading gives the viscosity of the tested oil directly in Centistokes at 40 o C. After a few trials, any operator can check the viscosity of oils to an accuracy of 95 percent or better; and if skillful, to even closer accuracy. Page 9 of 4
HOW TO BE CERTAIN THAT OILS ARE THE SAME TEMPERATURE: Slowly raise plunger end of VISGAGE to an angle between 30 to 45 degrees. Take two or three readings. If readings repeat, the oils are the same temperatures. If readings do not repeat, allow another few minutes to equalize temperature until a few readings repeat. The final repeat reading indicates the viscosity of the test oil directly in Centistokes at 40C. HOT OILS: WARNING: Do not immerse VISGAGE in hot oil/ or hot water to equal/is temperatures. Do not heat VISGAGE above 40C. CLEANING: The VISGAGE is self-cleaning. When the oil is discharged after a test, returning the plunger to its original position effectively cleans the wall of the test tube. A small a- mount of oil will remain in the bore of the nozzle. To discharge this, fill the test tube with the next oil to be tested, discharge and discard it. This will clean the nozzle of the previous oil before the new test is made. Non-use of the VISGAGE over a period of time with residue oil in the test tube may gum the sphere and the wall of the tube. To remove it, draw into the test tube a few charges of light oil or kerosene to dissolve the residue. Do not use straight gasoline or naphtha. DARK COLORED OILS: Dark colored oils in the test tube may make it difficult to see the sphere. To overcome this, follow standard test procedure under READING. Then, with your back to the light (Fig. 6) and full light on the scale, (Fig. 7 & 8) tilt reference tube toward you 90 degrees to bring the sphere in the test tube into sight. The point on the scale corresponding to the position of the sphere indicates the viscosity of the test oil direct at which it was rated in Centistokes at 40C. (Fig. 8) The VISGAGE is designed and constructed to test the viscosity of new and used oil/s but not sludge. Whenever the sphere in the test tube can no longer be seen, you will know the oil is so badly fouled with contaminants that it needs to be changed immediately or cleaned by any of the appropriate cleaning methods. VISCOSITY INDEX (VI): o The reference tube contains certified oil with a viscosity index of 95 VI. Best accuracy is achieved when the oil being tested has a VI near the VI of the reference oil, and several identical readings on the scale indicate temperatures of both tubes are equal. If the VI's of the oils are far apart (for example, 95 VI in reference tube, 40 VI in test oil), warm VISGAGE to 40C, and then take readings. Page 0 of 4
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After the sample has been taken Assuming that a 00 ml sample was drawn initially, a total of 72 ml will remain after 28 ml are used for the patch test kit. If desired and rather than discarding it, this remaining fluid could be submitted for an automated particle count under the new THF-PC testing performed at Schroeder s on-site lab. Not only would this provide verification for the patch test, but it would also generate a hard copy and/or electronic report of the sample s cleanliness level. Part number for this service is THF-PC. Request L-2533 for ordering information on this service. Be sure to identify the slides with either a permanent marker or a label: Date the sample was pulled, Customer, Equipment Id Note where the sample was pulled (i.e., return line before the filter, at the case drain return, off the reservoir sample valve, off the reservoir bottom, etc.) Note the oil s ISO Viscosity Grade (if known) Trouble Shooting Guide Problem Cause Solution Oil Can not be pulled through the patch Can not see anything through the microscope Can not create a vacuum ) Viscosity is too high 2) Contamination level is too high ) There is not enough light present 2) Microscope is zoomed in all of the way ) Bottle is not properly screwed on the vacuum pump 2) Check that the valve on the vacuum pump is not open or damaged ) Use solvent to dilute the sample 2) Do not pour the entire 28 ml of sample fluid in at once. Instead pour a small amount and pull through the vacuum 3) Ensure the 0.4 um patch is not being used ) Ensure the penlight is pointed directly onto the portion of the patch that is under the microscope 2) Move the microscope to a location with improved lighting 3) Zoom out and then begin to zoom in on the patch. ) Unscrew the bottle and then screw it onto the vacuum pump 2) Ensure the o-ring and spring is still enacted. If it is not contact Schroeder Industries, LLC. Page 2 of 4
Sampling Procedures- Appendix A: How to Take an Oil Sample Through a SchroederCheck Test Point This procedure assumes that a Schroeder Check test point has been permanently installed at a location where turbulent flow exists. Sampling Procedure:. To initiate the sampling process, simply screw the Microflex hose end into the Schroeder Check test point until resistance is encountered. This indicates the probe has made contact with the poppet (or ball in the case of ball check test point). The flow rate of the fluid through the hose will be directly affected by the size of the opening created when the poppet or ball is displaced by the probe. Continue screwing down the hose end until the desired flow rate is achieved. 2. Pass a minimum of 200 ml of fluid through the Schroeder Check test point before collecting the fluid into a waste container. 3. Place the sampling bottle in position to collect the fluid. Use a sampling bottle having a contaminant level of at least two decades lower than the expected sample as qualified per the American National Standard Procedure for Qualifying and Controlling Cleaning Methods for Hydraulic Fluid Power Fluid Sample Containers, ANSI/B93.20-972. (NFPA/T2.9.2-972, ISO 3722-976). 4. After removing the cap and plastic film from sample bottle, direct the fluid stream through the microflex hose into the bottle mouth. 5. Take a sample of not more than 80% nor less than 50% of the sampling bottle volume. 6. To terminate the sampling process, simply back off the hose gland nut at the Schroeder Check test point, keeping in mind that this operation should be performed before the container is completely filled. 7. Recap the sample bottle immediately. 8. Prior to taking additional samples, flush the microflex hose with a suitable solvent or fluid. Equipment Available from Schroeder Industries: Schroeder Check Test Point/Sampling Valves: Part Number SP25NPT4P ¼ NPT Part Number SP25UN76P 7/6 UNF Part Number SP25UN96P 9/6 UNF Microflex Hose Assembly for Schroeder Check Test Points Shown Above: Part Number SM2-25-036 3 feet Page 3 of 4
Sampling Procedures -Appendix B: Recommended Practices For Taking Oil Samples From a Hydraulic Reservoir Equipment and Supplies: NOTE: Use only materials compatible with the fluid sample.. Use sample bottles having a contaminant level at least two decades lower than the expected sample as qualified per the American National Standard Procedure for Qualifying and Controlling Cleaning Methods for Hydraulic Fluid Power Fluid Sample Containers, ANSI/B93.20-972. See below for availability. (NFPA/T.2.9.2-972, ISO 3722-976) 2. Use lint-free cloths, free of visible dirt. 3. Use a device to permit withdrawal of a sample. (See figure below) 4. Provide lengths of tubing. Sampling Procedure:. Find a convenient opening above the fluid level in the reservoir through which the sampling tube can enter. 2. Determine the approximate distance D/2 as shown to establish the depth of the reservoir sampling tube. 3. Place a reference mark on the sampling tube at a point corresponding to the length of the tubing needed to reach D/2 from the opening through which the sampling tube will enter. 4. Use lint-free cloth to clean all surfaces which could contribute contaminant to the fluid sample. 5. Operate the hydraulic circuits to help diffuse particulate contaminant as evenly as possible throughout the reservoir. NOTE: When a procedure to diffuse particulate contaminant has been established for a particular system, maintain that procedure for all similar systems. If a sample representing normal operating conditions is desired, do not operate the hydraulic circuits for prolonged periods in an artificially clean environment. 6. Insert the sampling tube into the reservoir to the reference mark immediately after the contaminant in the reservoir has been diffused per point 5. NOTE: It may be necessary to weight the end of the tubing to help it to be positioned at the desired level. 7. Flush sampling tube with reservoir fluid equal to approximately five times the internal volume of the sampling line. Do not use flushing fluid or flushing bottle to obtain fluid sample per point 8. 8. Withdraw a fluid sample from the reservoir into a clean sample bottle. Fill sample bottle to not more than 75 percent nor less than 50 percent of the sample bottle volume. 9. Remove sample bottle and recap immediately. NOTE: Hours of operation immediately prior to sampling is vehicle or system running time per point. Page 4 of 4