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Title:
SINTERED POROUS OIL INDICATING MEDIA AND APPLICATIONS THEREOF
Document Type and Number:
WIPO Patent Application WO/2018/071375
Kind Code:
A1
Abstract:
This invention relates to compositions comprising sintered porous media comprising dye particles in combination with plastic particles or elastomeric particles. These compositions are useful in detecting oil or organic solvents in air or water by changing color when the oil or organic solvent contacts the sintered porous media and dissolves the dye particles.

Inventors:
MAO, Guoqiang (338 N. Peachtree Parkway, Peachtree City, Georgia, 30269, US)
GIORDANO, Edward Carl (1129 Portsmith Circle, Marion, Iowa, 52302, US)
NIBLOCK, William D. (211 High Park Boulevard, Buffalo, New York, 14226, US)
Application Number:
US2017/055865
Publication Date:
April 19, 2018
Filing Date:
October 10, 2017
Export Citation:
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Assignee:
POREX CORPORATION (500 Bohannon Road, Fairburn, Georgia, 30213, US)
International Classes:
B01J20/14; B01D39/16; B01D46/00; B01J20/16; B01J20/26; B01J20/28; B01J20/30; C09K3/32
Foreign References:
US20080199363A12008-08-21
US20120318139A12012-12-20
US20080149571A12008-06-26
US8187534B22012-05-29
US8141717B22012-03-27
Attorney, Agent or Firm:
MCDONALD, John K. et al. (Kilpatrick Townsend & Stockton LLP, Suite 28001100 Peachtree Stree, Atlanta Georgia, 30309, US)
Download PDF:
Claims:
CLAIMS

1. A sintered porous hydrophobic composition for detecting oil or an organic solvent in water or air comprising a sintered porous matrix comprising solvent dye particles and polymeric plastic particles or elastomeric particles.

2. The porous matrix of claim 1 having an average pore size from about 0.1 microns to about 200 microns.

3. The porous matrix of claim 1 having an average water intrusion pressure greater than 2 inches of water.

4. The composition of claim 1 further comprising an oil absorptive material.

5. The composition of claim 1, wherein the dye particles have a solubility in water of less than 1 gm/100 ml, less than 0.1 gm/100 ml, or less than 0.01 gm/100 ml at room temperature.

6. The composition of claim 1, wherein the plastic particles are polyethylene, polypropylene, polyvinylidene fluoride (PVDF) and/or polytetrafluoroethylene (PTFE) particles. .

7. The composition of claim 1, wherein the plastic particles are ultrahigh molecular weight polyethylene particles.

8. An oil and water separation device comprising the composition of claim 1.

9. An air compressor comprising the oil and water separation device of claim 8.

10. An air filter comprising the composition of claim 1.

11. A pump muffler comprising the composition of claim 1.

12. Use of the composition of claim 1 in an oil and water separation device, an air compressor or a pump muffler.

13. A method of detecting oil or an organic solvent in water or air comprising:

providing the composition of claim 1 ;

permitting the water or air containing oil or an organic solvent to contact the composition; and,

changing the color of the composition, wherein the color change indicates the presence of the oil or the organic solvent.

14. A method of detecting oil in an oil water separator for an air compressor comprising: providing the composition of claim 1 in an oil water separator for an air compressor; permitting the water containing oil to contact the composition; and,

changing the color of the composition, wherein the color change indicates the presence of the oil.

15. The method of claim 13 or claim 14, wherein the oil is a polypropylene glycol based oil.

Description:
SINTERED POROUS OIL INDICATING MEDIA AND APPLICATIONS THEREOF

PRIOR RELATED APPLICATIONS

[0001] The present application claims the benefit of priority to U.S. Provisional Application No. 62/406,470 filed October 11, 2016 which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Oils, such as hydrocarbon oils and specifically polypropylene glycol based lubricant oils, are environmentally hazardous to the world water ecosystem. The Environmental Protection Agency (EPA) requires removal of oil from all produced or processed water before water is circulated back to the ecosystem. What is needed are materials to provide a simple and visual indication of the presence of oil in water. Current fiber based color indicators are not suitable for many applications because they only available in sheet form and cannot be used in many situations that require molded products to fit different machine designs.

[0003] Other than oil, many organic solvents also pose environmental hazards when present in water and air. Organic solvents need to be removed from the water and air before they are discharged into the environment.

[0004] Sintered porous color indicating materials are commercially available and are disclosed in US Patent 8,187,534. However, the dyes used in US 8,187,534 are basically food dyes and are water soluble. The purpose of color indicating materials in US 8,187,534 is to detect whether the materials have contacted water or an aqueous based solution. What is needed are materials to provide a simple visual indication of the presence of oil or organic solvents in water and air.

SUMMARY

[0005] The present invention solves these problems by providing compositions comprising sintered porous media comprising dyes particles in combination with plastic particles or elastomeric particles. These compositions are useful in detecting oil or organic solvents in air or water by changing color when the oil or organic solvent contacts the sintered porous media and dissolves the dye particles. Accordingly, these compositions provide a visual indication for oil or other organic solvents in the water or air. Pure water and pure air will not provide a visual detectable signal.

[0006] The present invention provides a sintered porous media that provides visual color indication when it encounters water or air contaminated with oil or an organic solvent.

[0007] The sintered porous media of the present invention provides a visual color indication when it contacts organic solvent vapor or aerosol.

[0008] The sintered porous media of the present invention can be used to provide a visual color indication when a device leaks an oil based liquid.

[0009] The sintered porous media of the present invention can change color or hue when it contacts oils or organic solvents. In some embodiments, the sintered porous media of the present invention are hydrophobic.

[0010] In different embodiments, the sintered porous media of the present invention can be used in an oil and water separation device, an air compressor or a pump muffler.

BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1. Comparison of sintered porous media and commercial 907-60 oil test paper (MACHEREY-NAGEL Inc. 2850 Emerick Blvd. Bethlehem, PA 18020) for 0.1% polypropylene glycol (PPG) based lubricant oil (Dow, Ultra-coolant) in deionized water. Left, commercial 907-60 oil test paper, middle, sintered porous ultrahigh molecular weight polyethylene (UHMWPE) with average pore size of 30 microns and 0.02% of oil blue N dye (Sigma) and right, sintered porous plastic with average pore size of 30 microns and 0.02% Sudan black B (Kodak). Sintered porous media show better sensitivity. PPG based lubricant in the water causes the sintered porous media to change color, which is evidenced by the darker areas and lines that appears on the test papers, shown in the middle and right images.

[0012] Figure 2. Sintered porous media for detecting oil vapor and aerosol in an air stream. The bottom part of sintered porous media was in an air stream containing oil vapor and aerosol. Oil vapor and aerosol generate distinguishable color change on the sintered porous media. These color changes are evidenced by the darker areas and lines that appear on each sintered porous media in the images. The oil used was Chevron 5-30W engine oil and oil aerosol was generated by a John Bunn nebulizer. The parts shown here are sintered porous ultrahigh molecular weight polyethylene (UHMWPE) with average pore size of 30 microns and with 0.02% weight percent dyes. They are (from left to right) with 0.02% Sudan III; with 0.02% Sudan black; with 0.02% oil blue N; with 0.02% oil blue N and 5% oil absorbent (Grainger).

[0013] Figure 3. Examples of different types of sintered porous media and examples of molded 3D devices.

[0014] Figure 4. A compressed air line filter shown in the figure could contain the sintered porous media of the present invention.

[0015] Figure 5. Sintered porous media for use in an oil pump muffler.

[0016] Figure 6. Sintered porous media can be used in an oil water separator for an air compresser shown in the figure.

[0017] Figure 7. Example of sintered porous media for use in an oil water separator for an air compressor. Two views are presented of a disposable cartridge where the porous oil- indicating element is positioned at the downstream end of the oil water separator's post-filter. This provides the function of alerting the user that the oil-absorptive media has been fully consumed and requires replacement.

DETAILED DESCRIPTION

[0018] The present invention provides compositions comprising sintered porous media comprising dye particles in combination with plastic particles or elastomeric particles. These compositions are useful in detecting oil or organic solvents in air or water by changing color when the oil or organic solvent contacts the sintered porous media and dissolves the dye particles. Accordingly, these compositions provide a visual indication for oil or other organic solvents in the water or air. The terms sintered porous media and sintered porous matrix are used interchangeably in this application.

[0019] In different embodiments, the sintered porous media of the present invention comprise a solvent dye in combination with a polymeric plastic or an elastomer. Solvent dye particles and polymeric plastic or elastomer particles are combined and sintered to form the sintered porous media.

[0020] The solvent dyes are organic colorants that have higher solubility in oils and organic solvents than in water. The solvent dyes used in the present invention have solubilities in water of less than 1 gram (gm)/100 ml water, less than 0.1 gm/100 ml water, or less than 0.01 gm/100 ml water at room temperature.

[0021] In another embodiment, the sintered porous media comprise more than one solvent dye. The different solvent dyes may have different oil solubilities. [0022] In different embodiments, the sintered porous media have an average pore size from about about 0.1 microns to about 200 microns, from about 0.2 microns to about 200 microns, from about 0.5 microns to about 100 microns, from about 1 micron to about 80 microns, or from about 5 microns to about 50 microns.

[0023] In various embodiments, the sintered porous media have an average porosity of about 20% to about 70%, from about 25% to about 60 %, or from about 30% to about 50 %.

[0024] In different embodiments, the sintered hydrophobic porous media of the present invention have an average water intrusion pressure greater than about 2 inches of water, greater than about 5 inches of water, greater than about 10 inches of water, greater than about 15 inches of water or greater than about 27 inches of water.

[0025] Polymeric plastics and elastomers for use in the present invention can be any polymer that can be sintered into porous media as disclosed in US Patent 8, 141 ,717. The sintered porous media will have the same pore size, pore volume and mechanical properties as the sintered porous plastic or elastomeric media disclosed in US 8,141 ,717. In some embodiments polyethylene, polypropylene, polyvinylidene fluoride (PVDF) or polytetrafiuoroethylene (PTFE) are employed. In one embodiment, ultrahigh molecular weight polyethylene (UHMWPE) is used.

[0026] Solvent dyes in the present invention are at concentrations of less than 1 %, less than 0.1 %, less than 0.05%, less than 0.02% or less than 0.01 %, but more than 0.0001 % (all in wt.% of the sintered hydrophobic porous media).

[0027] Solvent dyes in the present invention include, but are not limited to, solvent red 1 , solvent red 3, solvent red 18, solvent red 24, solvent red 26, solvent red 164, solvent yellow 14, solvent yellow 16, solvent yellow 29, solvent yellow 56, solvent yellow 124, solvent blue 35, solvent blue 70, solvent black 3, and solvent black 7 or a mixture thereof.

[0028] The dyes may be also fluorescent dyes, including but not limited to, acridine dyes, cyanine dyes, fluorine dyes, oxazine dyes, phenanthridine dyes and rhodamine dyes.

[0029] Oils that may be detected with the sintered porous media of the present invention include, but are not be limited to, hydrocarbon oils; polyalphaolefin oils (PAO); polyinternal olefin oil (PIO); mineral oils; silicone oils, naphthenic oils, polyalkylene glycols (PAG) oils, such as polypropylene glycol (PPG) oils; phosphate ester oils; multiple alkylated cyclopentanes (MAC) oils, and a mixture thereof. Oils that may be detected with the sintered porous media also include fuels, such as gasoline, diesel, and kerosene. [0030] Organic solvents that may be detected with the sintered porous media are liquid organic solvents that may or may not be miscible with water. The water miscible organic solvents include, but are not limited to, alcohols, such as, methanol, ethanol, propanol, isopropanol, butanol; aldehydes; ketones; tetrahydrofuran (THF), dimethylsulfoxide (DMSO), dimethylformamide (DMF), N-Methyl-2-pyrrolidone (NMP), cyclohexanone, etc. The water immiscible organic solvents include, but are not limited to, alkanes; alkenes, aromatic hydrocarbons, such as benzene, toluene, xylene; halide solvents, such as methylene chloride, chloroform, tetrachlorocarbon, dichloroethylene; ethers; and liquid esters, such as ethyl acetate.

[0031] In one embodiment, the sintered porous media of the present invention may change from a light hue to a darker hue with the same color, such as from light blue to dark blue, from light red to dark red, from light purple to dark purple, from light yellow to dark yellow, etc. upon contact with oils or organic solvents.

[0032] In another embodiment, the sintered porous media of the present invention change from one color to another color.

[0033] In some embodiments, the sintered porous media comprise at least two different solvent dyes with different solubilities in oil or organic solvents. The different solubilities of the solvent dyes cause the change of the color appearance of sintered porous media.

[0034] In another embodiment, the sintered porous media may further comprise one or more oil absorptive materials. These materials include, but are not limited to, anthracite, laumontite, organoclays, or modified zeolites from TIGG LLC, (1 Willow Avenue, Oakdale, PA 15071), synthetic copolymer of 1-octene and isodecyl acrylate copolymer, acrylate polymers, styrene-ethylene-butylene based copolymers, Envio-bond® 403, TOTALSORB®, TOTALSORB® Plus, and OrganoLock N-65 from M2 Polymer Technologies, Inc. (West Dundee, Illinois, USA).

[0035] The sintered porous media can have different physical shapes, such as tube, sheet, rod, disk and molded three-dimensional structures.

[0036] In some embodiments, different regions of a sintered porous media may have different solvent dyes that produce different colors upon contact with an oil or organic solvent.

[0037] In another embodiment, one region of a sintered porous media may have solvent dyes and another region may not have a solvent dye. For example, a sintered porous media may have a layered structure, wherein one layer comprises one or more solvent dyes and another layer does not comprise a solvent dye. In one embodiment, the region without a solvent dye is white and region with a solvent dye is colored.

[0038] In yet another embodiment, a sintered porous media may have a region with one or more solvent dyes for oil detection and another region with different solvent dyes for organic solvent detection.

[0039] Hydrophobic sintered porous plastic media permit only the low surface energy oil to wick into the porous media but do not permit high surface energy water to enter the pore structure of the sintered porous plastic media. The hydrophobic sintered porous media changes its light refractivity when its pores contain oil, organic solvents or other low surface tension liquids.

[0040] The dyes in the sintered porous media have very low water solubility and dissolve in the oils or organic solvents that enter the pores. The dissolved dyes provide a colored visual signal on the sintered porous media.

[0041] When sintered porous media detect oil vapor or aerosol in an air stream, the oil vapor or aerosol in the air stream dissolves the solvent dyes inside sintered porous matrix and the dissolved dyes are carried by the air stream to another location of the sintered porous media. The uneven distribution of solvent dyes in the sintered oil generates a colored visual signal on the sintered media.

Method of making the sintered porous media for detecting oil or organic solvents

[0042] Sintered porous media of the present invention are made by co-sintering polymeric particles with solvent dye particles. The sintering conditions are disclosed in US 8, 187,534 and US 8, 141 ,717 for making sintered porous media. The total amount of solvent dyes is less than 1 %, less than 0.1%, less than 0.05%, less than 0.02% or less than 0.01%, but more than 0.0001% (all in wt.% of the sintered porous media).

[0043] In one embodiment, sintered porous media of the present invention are made by solution coating of a sintered porous polymeric media with a solution containing solvent dyes. The solvent dye solution should be less than 1%, less than 0.1%, less than 0.05%, less than 0.02% or less than 0.01 %, but more than 0.0001 %. The solvents are chosen based on dye solubility in the solvent as known to one of ordinary skill in the art. The common solvents are acetone, isopropanol and ethyl acetate. In one embodiment, sintered porous media are dipped in the solution containing 0.1 % of solvent dye solution and then dried at room temperature. [0044] In another embodiment, sintered porous media are made by printing a sintered porous polymeric media with a solution containing solvent dyes. In one embodiment, printing is accomplished through ink jet printing. A solution containing solvent dyes is printed on the sintered porous media and the solvent dyes are absorbed into the sintered porous media. The solvent dye solution should be less than 1%, less than 0.1%, less than 0.05%, less than 0.02% or less than 0.01%, but more than 0.0001% (all in wt.% of the sintered porous media). The solvents are chosen based on dye solubility in the solvent as known to one of ordinary skill in the art. The common solvents are acetone, isopropanol and ethyl acetate. In one embodiment, an ink jet is used to spray dye solution onto a specific location of the sintered porous media and then the sintered porous media is dried at room temperature.

Application of sintered porous oil color indicating media

[0045] Sintered porous media can be a disposable test strip for testing oil in the water. This is a sintered sheet for a product with similar thickness to the current oil testing strip 907- 60 made by MACHEREY-NAGEL Inc. (2850 Emerick Blvd. Bethlehem, PA 18020).

[0046] Sintered porous media in the present invention can be used as an oil indicator in a device that monitors oil content in water, such as an oil water separation device. According to EPA regulations, all water must be monitored for oil content before discharge. These include waste water treatment, secondary containment, an oil production facility, an oil recovery and/or recycling facility, air compressor condensation, surface water run-off, boiler condensation return, cooling water and produced water discharge, and marine bilge water. The present invention does not replace current methods, but provides a complementary visual indication of the presence of oil.

[0047] One specific use of the sintered porous media is as an oil indicator for a compressor condensation drainage tank and oil water separator.

[0048] The sintered porous media can also be used as an oil indicator for a vacuum line or a compressed air line. Oil vapor or aerosols are commonly produced in the compressor. Oil aerosols in the air line generally indicate there is leak in the pump system. Oil in the compressed air affects compressed air function as a cleaning tool and needs to be removed. Compressed air lines usually have a pre-filter (made from sintered porous plastic or fiber), a coalescing filter, a dryer (option) and an after filter. The sintered porous media of the present invention can be used as pre-filter and as an after filter to monitor the oil from the pump (pre- filter) and the effectiveness of the coalescing filter (after filter).

[0049] In another embodiment, the sintered porous media of the present invention can be used as a muffler for a vacuum pump to indicate the end of functional life of the muffler and that service is needed due to excess generation of oil aerosol.

[0050] The sintered porous media can be used as an absorbent and color indicator for a device containing an oil based ingredient, for example as a condensation and leakage indicator for the e-liquid in an e-cigarette.

[0051] The following examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof. On the contrary, it is to be clearly understood that resort may be had to various embodiments, modifications and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention.

EXAMPLE 1

[0052] Blue colored sintered porous oil color indicating media

[0053] 99.98 g of UHMWPE powder with an average particle size of about 120 microns and 0.02 g of oil blue N dye were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were blue colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with average pore size about 28 microns and 45% porosity.

EXAMPLE 2

[0054] Purple colored sintered porous oil color indicating media

[0055] 99.98 g of UHMWPE powder with an average particle size of about 120 microns and 0.02 g of Sudan Black dye were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were purple colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with an average pore size about 28 microns and 45% porosity. EXAMPLE 3

[0056] Orange colored sintered porous oil color indicating media

[0057] 99.98 g of UHMWPE powder with an average particle size of about 120 microns and 0.02 g of Sudan III dye were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were orange colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with average pore size about 28 microns and 45% porosity.

EXAMPLE 4

[0058] Sintered porous oil color indicating media comprising oil absorbent and solvent dyes

[0059] 94.98 g of UHMWPE powder with an average particle size of about 120 microns, 0.02 g of oil blue N dye and 5 g of oil absorbent (OptiSorb®, Grainger) were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were light purple colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with an average pore size about 28 microns and 45% porosity.

EXAMPLE 5

[0060] Sintered porous oil color indicating media with multiple solvent dyes

[0061] 99.98 g of UHMWPE powder with an average particle size of about 120 microns, 0.01 g of oil blue N dye and 0.01 g of oil red O dye were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were light blue colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with an average pore size about 28 microns and 45% porosity. EXAMPLE 6

[0062] Sintered porous oil color indicating media comprise oil absorbent and solvent dyes

[0063] 94.98 g of UHMWPE powder with an average particle size of about 120 microns, 0.02 g of oil blue N dye and 5 g of oil absorbent (OptiSorb®, Grainger) were mixed together and formed a uniform mixture. The mixed powder was filled into the cavities of an aluminum mold and heated to 360° F for five minutes and then cooled to room temperature in five minutes. The parts were removed from the mold. The resulting parts were light purple colored porous materials with the shape of the cavity in the mold. The parts had an open pore structure with an average pore size around 28 microns and 45% porosity.

EXAMPLE 7

[0064] Use of sintered porous oil indicating media to detect polyethylene glycol-based compressor oil in water

[0065] An oil testing strip 907-60 made by MACHEREY-NAGEL Inc., blue colored sintered porous oil indicating media strip (see example 1) and purple colored sintered porous oil indicating media strip (see example 2) were used. The strips were dipped into a water solution containing 100 ppm polypropylene glycol-based lubricating oil for 2 seconds. The strips were removed from the solution and the oil mark was observed. Oil marks were visible on the sintered porous oil indicating media, but not on the oil testing strip 907-60 made by MACHEREY-NAGEL Inc. Sintered porous oil indicating media had better sensitivity for detecting oil in water than the currently available commercial product. (In figure 1, oil testing strip 907-60 (left), blue colored sintered porous oil indicating media (middle) and purple colored sintered porous oil indicating media (right) are shown). In the middle image, the sintered porous media is illustrated as having a darker line where indication is shown. Because the test strip was light blue, indication is evidenced to the user by a darker blue area and line gradation. (Although color cannot be shown in the images, the color change can be seen where the area and line become darker.) In the right image, the sintered porous media is illustrated as having a darker line where indication is shown. Because this test strip was light purple, indication is evidenced to the user by a darker purple area and line gradation. (Although color cannot be shown in the images, the color change can be seen where the area and line become darker.) EXAMPLE 8

[0066] Use of sintered porous oil indicating media to detect oil in an air stream

[0067] Four colored sintered porous oil indicating media strips made according to example 1 , example 2, example 3 and example 4 were used for the test. The strips were mounted on one end of 6 inches of Tygon tubing and the other end of Tygon tubing was connected to a B Braun Nebulizer. The nebulizer generates an air flow rate of about 8 liters/minute. 0.5 ml 3-30W Shell brand engine oil was added to nebulizer reservoir. After the nebulizer was activated, the color of colored sintered porous oil indicating media was observed after two hours. A control experiment was run without oil in the nebulizer.

[0068] The color of sintered oil indicating media changed in the location contacting the air stream containing oil aerosol, but not in the air stream without oil aerosol. Figure 2 shows four different sintered oil indicating media after they contacted the air stream containing oil aerosol. Shown from left to the right in Figure 2 are orange colored sintered oil indicating media (Example 3), purple colored sintered porous oil indicating media (Example 2), blue colored sintered porous oil indicating media (Example 1) and purple colored sintered oil indicating media (Example 4). Although color cannot be shown in the images, indication is evidenced to the user by a darker color and line gradation on the strip. The area where the color change takes place can be seen in the images where the area and line become darker. The sintered porous oil indicating media did not show noticeable color change in the air streams that did not contain oil aerosol.

EXAMPLE 9

[0069] Use of sintered porous oil indicating media to detect oil in an oil water separatoror an air compressor

[0070] Light blue colored sintered porous oil indicating media disk made according to example 1 is used in the test. The disk is mounted on the outlet port of an oil water separator by press fit (Figure 7). The darkness of the blue color of sintered porous oil indicating media is observed. Once the blue color attains a certain darkness, it indicates that the outflow water contains excess amount of oil and that the oil absorbent media in the oil water separation device needs to be changed. When the color change is evident, an action is required which could include, but is not limited to: changing the media, regenerating the media, switching flow between operational units, replacement of the indicator element, or another service action.

[0071] All patents, patent applications, publications, and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.