Patent Grant
9737900
This disclosure relates generally to in-situ pipe coating, and more particularly, to centrifugal resin application with a coating cone.
Infrastructure pipelines that carry fluids such as potable water, gas, and wastewater deteriorate over time due to their extensive use. This deterioration can lead to leaks and bursts resulting in costly damage if the pipelines are not maintained. Since these pipelines are typically located underground and provide essential utilities, maintenance and rehabilitation is preferably performed with as minimal disruption to service as possible. Several methods for performing in-situ maintenance and rehabilitation on these pipes, known as trenchless methods, have been developed. One such method involves feeding an applicator device through the pipe to spray a material along the interior surface of the pipe. The material then hardens to form a new, interior liner surface to seal cracks and strengthen the existing pipeline.
An embodiment of the present disclosure is directed to an in-situ applicator for applying a composition in a pipe. The applicator comprises a flow diverter and a hollow conical body. The flow diverter is configured to receive the composition and eject the composition from at least one outlet. The hollow conical body has a narrow end, a broad end, and an interior surface configured to receive the composition ejected from the flow diverter. The conical body also has a plurality of holes forming a band that wraps circumferentially around the conical body and defines a flow region on the interior surface between the band and the narrow end. The band includes first holes adjacent to the flow region where each of the first holes has a first average diameter and second holes disposed between the first holes and the broad end, each of the second holes having an average diameter greater than the first diameter. The flow region is devoid of holes and has a first, second, third, and fourth inclined side where proximate ends of the first and second sides converge toward the narrow end and proximate ends of the third and fourth sides converge toward the narrow end in a mirror image of the proximate ends of the first and second sides.
Another embodiment is directed to a method. The method involves providing an applicator having a flow diverter and a hollow conical body as set forth above. A composition is fed to the flow diverter, and the composition is ejected from the at least one outlet to collect on the interior surface of the hollow conical body. The hollow conical body is rotated so that the collected composition flows over the flow region toward the plurality of holes and sprays outwardly from the hollow conical body through at least two of the plurality of holes.
A further embodiment is directed to an apparatus. The apparatus includes an input tube and an outlet portion. The input tube has a first axis, a first diameter, and an opening at a proximate end. The outlet portion has a second diameter and is arranged at the distal end of the input tube with a domed end transverse to the first axis. The outlet portion comprises at least two outlets arranged perpendicular to the first axis.
These and other aspects of the present disclosure will be apparent from the detailed description below. In no event, however, should the above summaries be construed as limitations on the claimed subject matter, which subject matter is defined solely by the attached claims, as may be amended during prosecution.
The following figure descriptions are presented in connection with various embodiments of the disclosure.
In the figures, like reference numerals designate like elements.
One technique for spray coating the interior surface of a pipe involves centrifugally spraying a liquid liner, or resin composition, with a hole-patterned cone. This technique provides increased uniformity in the resulting liner. However, the technique can also result in coating defects such as sagging, lumping, or ringing. These defects occur, for example, when the ejected resin flows down the surface of the pipe before hardening, flows out the end of an open cone, or the rate at which the cone is fed through the pipe is irregular while steady-state resin delivery is maintained. Further complications arise when the resin clogs the holes of the cone and/or builds up inside the cone clogging the holes and/or the resin spray device thereby further preventing the cone from spinning. Clogs can range from a blockage of a few of the holes on the cone pattern or spray outlet(s) to filling the entire cone with hardened resin resulting in the inability to complete the lining application. Clogs that inhibit the uniform coating ability of the cone require extraction of the cone from the pipe for manual resin removal and typically also result in defects in the liner at that location in the pipe. Further, damage can occur to the cone during extraction of the hardened resin resulting in a need for a replacement cone.
Many factors influence the final pipe coating caliper and integrity, one of which is the resin chemistry. For example, fast setting, high viscosity, statically mixed, polyurea coating chemistries harden to at least a tack-free state in a matter of seconds once applied to the interior surface of a pipe (or to portions of the coating applicator). These resin chemistries are typically two-part chemistries including a first part comprising one or more aliphatic polyisocyanates, optionally blended with one or more amine reactive resins and/or non-reactive resins and a second part comprising one or more polyamines optionally blended with one or more oligomeric polyamines. The two parts, when mixed together and applied to the internal surfaces of pipelines, form a rapid setting impervious coating suitable for contact with drinking water.
The first part aliphatic polyisocyanate(s) may be any organic isocyanate compound containing at least two isocyanate functional groups, said isocyanate groups being aliphatic in nature. Suitable polyisocyanates include hexamethylene-1,6-diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; isophorone diisocyanate; and 4,4′-dicyclohexylmethane diisocyanate. Alternatively, reaction products or prepolymers derived from the above may be utilized, such as, polyisocyanate derivatives of hexamethylene-1,6-diisocyanate. The polyisocyanate compounds typically have an isocyanate content of between 5 weight percent (wt %) and 50 wt %, and more specifically, 20-25 wt %. The amine reactive resin(s) of the first part can be any compound containing functional groups which are capable of reacting with primary or secondary amines. Useful materials include epoxy functional compounds and any compounds containing ethylenically unsaturated bonds capable of undergoing “Michael Addition” with polyamines, e.g. monomeric or oligomeric polyacrylates. Non-reactive resins may also be used if they have no adverse effects on water or gas quality during pipe operation.
The second part of the two part coating comprises one or more polyamines. As used herein, polyamine refers to compounds having at least two amine groups, each containing at least one active hydrogen (N—H group) selected from primary amine or secondary amine. In some embodiments, the second component comprises one or more secondary amines. In certain embodiments, the amine component comprises at least one aliphatic cyclic secondary diamine.
In one embodiment, the second part comprises one or more aliphatic cyclic secondary diamines that comprise two, optionally substituted, hexyl groups bonded by a bridging group. Each of the hexyl rings comprises a secondary amine substituent.
The aliphatic cyclic secondary diamine typically has the general structure:
wherein R1 and R2 are independently linear or branched alkyl groups, having 1 to 10 carbon atoms. R1 and R2 are typically the same alkyl group. Representative alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, and the various isomeric pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. The symbol “S” in the center of the hexyl rings indicates that these cyclic groups are saturated. The preferred R1 and R2 contain at least three carbons, and a butyl group is particularly favored, such as a sec-butyl group.
R3, R4, R5, and R6 are independently hydrogen or a linear or branched alkyl group containing 1 to 5 carbon atoms. R3 and R4 are typically the same alkyl group. In some embodiments, R5 and R6 are hydrogen. In some embodiments, R3 and R4 are methyl or hydrogen.
The substituents are represented such that the alkylamino group may be placed anywhere on the ring relative to the CR5R6 group. Further, the R3 and R4 substituents may occupy any position relative to the alkylamino groups. In some embodiments, the alkylamino groups are at the 4,4′-positions relative to the CR5R6 bridge. Further, the R3 and R4 substituents typically occupy the 3- and 3′-positions.
In another embodiment, the second part comprises one or more aliphatic cyclic secondary diamines that comprise a single hexyl ring. The aliphatic cyclic secondary diamine typically has the general structure:
wherein R7 and R8 are independently linear or branched alkyl groups, having 1 to 10 carbon atoms or an alkylene group terminating with a —CN group. R7 and R8 are typically the same group. Representative alkyl groups include the same as those described above for R1 and R2. In one embodiment, R7 and R8 are alkyl groups having at least three carbons, such as isopropyl. In another embodiment, R7 and R8 are short chain (e.g. C1-C4) alkylene groups, such as ethylene, terminating with a —CN group.
R9, R10, and R11 are independently hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms. R9, R10, and R11 are typically the same alkyl group. In some embodiments, R9, R10, and R11 are methyl or hydrogen. In one embodiment R9, R10, and R11 are methyl groups.
The substituents are represented such that the alkylamino group may be placed anywhere on the ring relative to the —NR8 group. In some embodiments, the alkylamino group is two or three positions away from the —NR8. The preferred alkylamine group is two positions away from the —NR8 group on the cyclohexyl ring.
Alternatively the polyamine(s) of the second part may render the resin suitable for coating pipes that transport fluids such as wastewater or gas. Exemplary fast setting resin chemistries that may be employed with the disclosed apparatus and methods are further described in U.S. Pat. Nos. 6,730,353 and 7,189,429 (both to Robinson) and in PCT Application No. WO20120161774 (to Prince et al.). An exemplary commercially available resin is 3M SCOTCHKOTE Pipe Renewal Liner 2400. While the disclosed apparatus and methods may be employed with a variety of resin chemistries, substantially uniform coating has been attained for resin chemistries with tack-free times in the range of 10-90 seconds, and more preferably, less than 30 seconds. More preferably, substantially uniform coating may be attained for resin chemistries having a tack-free time of 24.5±1.7 seconds. These relatively fast tack-free times provide for a return-to-service of the pipe approximately two hours after coating is completed.
In addition to chemistries with relatively fast tack-free times as discussed above, compositions with a variety of chemistries and varying tack-free times may be used with disclosed embodiments. For example, polyurethanes including aromatic isocyanates and a polyol may be used.
Other factors influencing the final pipe coating caliper and integrity include volumetric flow rates, coating head speed, linear coating speed, resin viscosity during the coating process, and design of the cone. For example, the size of a coating cone selected for application of a resin depends upon the diameter of the pipe to be coated. Typically the broad end of the coating cone has at least a one inch clearance from the interior pipe surface. Also, the longer the pipeline to be coated, the more resin that needs to be pumped through the applicator. This factor increases in importance as increased coating calipers, for example up to 8.5 millimeters for a single pass coating, are desired. As volumetric flow rates increase, and coating head rotational speed remains constant, coating cones with greater surface area are required. The coating cone should be designed to apply the widest spray band possible for a given flow rate and pipe diameter. The spray band is defined as the maximum longitudinal distance that resin flows down the cone in the direction primarily parallel to the pipe while exiting the cone in a direction primarily orthogonal to the pipe wall. More efficient use of coating cone length and the larger resulting spray bands, increase the uniformity of the resin application and final lining caliper. These factors alone, and in combination, are considered when selecting a resin applicator for in-situ pipe maintenance and rehabilitation.
Turning now to
Similar to the above description of components,
A coating cone may be either a closed cone design or an open cone design, as illustrated in
Flow region 340 may be considered in two zones: resin distribution zone 348 and resin flow zone 352. Resin distribution zone 348 is located from narrow end 310 to the circumference of cone 300 at the closest holes to narrow end 310 (e.g., hole 354). Resin flow zone 352 is the triangular regions of interior surface of cone 300 defined by the circumference of cone 300 at the closest holes to narrow end 310 (e.g., hole 354) and the four inclined sides. The two triangular regions of resin flow zone 352 form mirror images of each other.
An exemplary coating cone hole pattern is shown in
All holes not adjacent to flow region 540 are second holes 534. Second holes 534 of the hole pattern of cone 500 also include elongated holes 536. Elongated holes 536 are holes not adjacent to flow region 540 and have an average diameter at least twice as large as the average diameter of first holes 532. The measurement of a diameter of a non-circular shape is taken along the longest axis between two opposing points of the shape. The term “diameter” is not limited to items or shapes that are circular. Elongated holes 536 serve as a safety measure to eject any resin remaining in the cone after flowing past first holes 532 and any other second holes 534. This enhances utilization of the length of the cone resulting in a wider spray band and more uniform caliper lining. As a further preventative measure, a row of holes is disposed around the circumference of cone 500 at broad end 520. This last row is configured to eject all remaining resin and prevent excess resin from leaving the cone through the open end, which would generate defects in the pipe lining such as clumping or ringing. An inner cone diameter 530 distinguishes between resin distribution zone 538 and resin flow zone 542.
While first and second holes 532, 534, with the exception of elongated holes 536, are typically circular in shape, there may be irregularities due to milling or manufacture of cone 500. In certain embodiments, such as smaller sized cones, first and second holes 532, 534, with the exception of elongated holes 536, have about the same average diameter. In other embodiments, second holes 534 have an average diameter larger than the average diameter of first holes 532. In embodiments utilizing fast setting resins, such as those discussed above, the smallest hole diameter can be one sixteenth of an inch (1.5 mm) to avoid clogging the holes of the cone. The average hole diameters for first and second holes 532, 534 are selected based on the resin chemistry being employed (e.g., viscosity and/or tack-free time), the size of the pipe being coated, and/or the flow rate of resin application.
Domed end 740 also includes at least one outlet 750 arranged perpendicular to the first axis. In one embodiment outlets 750 eject the resin from flow diverter 700 at a ninety degree angle with respect to the first axis. Thus, the resin first contacts the inner surface of a coating cone directly opposite outlets 750. In other embodiments, outlets 750 are angled so that the resin is ejected at an angle greater than ninety degrees (e.g., 105 degrees) with respect to the first axis. Thus, the resin first contacts the inner surface of a coating cone further along the cone, or forward, than if outlets 750 were not angled. Angling outlets 750 enables the resin to utilize more of the length of interior cone surface in larger (e.g., longer) cones to increase the size of the spray band and resulting caliper uniformity. Outlets 750 may vary in diameter based upon the resin applied, amount of resin, and flow rates for application. For example, larger flow rates and/or lower viscosity resins would be paired with larger outlet diameters. An example outlet diameter for the fast-setting resin described above would be about a quarter inch (6.35 mm).
A top-down view of an assembled 800 flow diverter 830 and coating cone 850 is provided in
In-situ applicators were assembled according to the disclosure as a hollow conical body or a cone, a flow diverter, and a stabilizer. The components were characterized via the following test procedures to establish flow rate and resin coat caliper or thickness.
Flow Rate
Flow rate was determined using a calibrated set of flow meters connected to an Allen Bradley Panel View Plus 700 programmable logic controller (PLC), obtained from Rockwell Automation Inc, Milwaukee, Wis. Two VSE Precision Flow Meters Model VS 1 available from IC Flow Controls, Inc. Normal, Ill. measured flow rate on the first and second part resin lines. The volumetric flow rate from the first part line and the measurement from second part line were summed together and reported as a combined total flow rate. Volumetric flow rate was recorded at the PLC every 8 to 10 seconds during a lining trial. Air motor operation was held constant at 10,000 rpm throughout the test.
Caliper Test
The process for determining the thickness of the resin coated in the pipe by the in-situ applicator was performed as follows. A 6.1 meter (20 feet) section of polyvinyl chloride (PVC) pipe was coated with resin and allowed to cure for one hour. The coated PVC pipe was cross-sectioned cut at 0.9 m (3 feet), 3.0 m (10 feet), and 5.2 m (17 feet) from the end of the pipe. The coating was removed from the pipe. An Absolute Digimatic Caliper from Mitutoyo America Corp, Aurora, Ill. was used to measure the caliper, or thickness, of the resin coating around the circumference at twelve hour hand intervals.
Table 1 summarizes dimensional characteristics of exemplary cones used for applying a composition in a pipe. The flow zone surface area was computed as the surface that is exposed to the resin as it is ejected from the flow diverter. Flow zone surface area was approximated as two triangles in
Table 2 summarizes the exemplary hole pattern and dimensional characteristics on the hollow conical bodies used for applying a composition in a pipe.
Table 3 summarizes dimensional characteristics of the exemplary flow diverter used for applying a composition in a pipe.
Table 4 summarizes dimensional characteristics of the exemplary stabilizer used for applying a composition in a pipe.
In accordance with the disclosure, the hollow conical body or cone was designed to uniformly apply the composition in a pipe for varying flow rates. As was described in the test methods, a maximum flow rate was calculated for each cone. The flow rate was used to determine a ratio of the hole surface area to the flow surface area of the cone. It was determined that substantially uniform resin coating resulted when the resin exited from the first row of the hole pattern. Computed flow rates in liters per minute (LPM) and surface area ratios are summarized in Table 5.
The ratio of first row hole surface area and the cone flow surface area is between 3:50 and 1:50 to produce a uniform line coat at or below the maximum flow rate for each cone.
Caliper of an applied liner was determined by coating a length of pipe and cutting the pipe into three cross sections at 0.9 m (3 feet), 3.0 m (10 feet), and 5.2 m (17 feet). Twelve measurements were recorded around the circumference of the pipe at hour hand intervals for an in-situ applicator with a one-outlet diverter. Cone 2 was used in the computation. Results were normalized with respect to the average caliper and range across all cross sections and are represented in
The normalized average caliper and range of thickness of the three cross section cuts for one-outlet ejection of the composition were 1.0 mm and 0.6 mm.
Caliper of an applied liner was determined by coating a length of pipe and cutting the pipe into three cross sections at 3 0.9 m (3 feet), 3.0 m (10 feet), and 5.2 m (17 feet). Twelve measurements were recorded around the circumference of the pipe at hour hand intervals for an in-situ applicator with a three port diverter. Cone 2 was used in the computation. Results were normalized with respect to the average caliper and range across all cross sections and are represented in
The normalized average caliper and range of thickness of the three cross section cuts for the three-outlet ejection of the composition were 0.9 mm and 0.1 mm. The results indicate that a three-outlet flow diverter provides improved uniformity of the resin coating compared with the one-outlet flow diverter described in Examples 4-6.
The position of the flow diverter in relation to the angle of the ports incident to the cone surface were determined to enhance coating uniformity. Results are summarized in Table 8. Distances were measured from the center of the flow diverter to the center of the first hole on the first row.
Following are a list of embodiments of the present disclosure.
Item 1 is an in-situ applicator for applying a composition in a pipe, the applicator comprising:
a flow diverter configured to receive the composition and eject the composition from at least one outlet; and
a hollow conical body having a narrow end, a broad end, and an interior surface configured to receive the composition ejected from the flow diverter, the conical body also having a plurality of holes, the plurality of holes forming a band that wraps circumferentially around the conical body and defines a flow region on the interior surface between the band and the narrow end, the band includes first holes adjacent to the flow region where each of the first holes has a first average diameter and second holes disposed between the first holes and the broad end, each of the second holes having an average diameter greater than the first diameter, the flow region being devoid of holes and having a first, second, third, and fourth inclined side where proximate ends of the first and second sides converge toward the narrow end and proximate ends of the third and fourth sides converge toward the narrow end in a mirror image of the proximate ends of the first and second sides.
Item 2 is the applicator of item 1, wherein the second holes include elongated holes, each having an average diameter at least twice as large as the first diameter.
Item 3 is the applicator of item 1, wherein each of a plurality of second holes adjacent the first holes is disposed offset from the first holes and between at least two of the first holes.
Item 4 is the applicator of item 1, wherein the average first diameter is based on the viscosity of the composition.
Item 5 is the applicator of item 1, wherein the average first diameter is based on the tack-free time of the composition.
Item 6 is the applicator of item 1, wherein the average first diameter is at least 1.5 mm.
Item 7 is the applicator of item 1, wherein the interior surface of the conical body includes a composition distribution zone proximate the narrow end.
Item 8 is the applicator of item 1, further including a stabilizer for coupling the hollow conical body to a rotational apparatus.
Item 9 is the applicator of item 1, wherein the hollow conical body is an open cone.
Item 10 is the applicator of item 1, wherein the hollow conical body is a closed cone.
Item 11 is the applicator of item 1, wherein the plurality of holes form a pattern on the hollow conical body configured to separate flow of the composition into at least two regions of the interior surface of the hollow conical body.
Item 12 is the applicator of item 1, wherein an inner diameter of the narrow end of the hollow conical body is greater than an outer diameter of the flow diverter.
Item 13 is the applicator of item 1, wherein the composition has a tack-free time in a range of 10-90 seconds.
Item 14 is the applicator of item 1, wherein the band of holes defines a first chevron proximate the first and second inclined sides of the flow region and a second chevron proximate the third and fourth inclined sides of the flow region, the first and second chevrons being on opposing sides of the hollow conical body.
Item 15 is the applicator of item 14, wherein the first and second chevron each comprises at least two nested rows of holes.
Item 16 is the applicator of item 15, wherein for each of the first and second chevrons, the at least two nested rows of holes includes a first row of holes adjacent to the flow region and a second row of holes disposed between the first row of holes and the broad end, each of the holes in the first row of holes having an average hole diameter smaller than an average hole diameter of each of the holes in the second row of holes.
Item 17 is the applicator of item 1, wherein the hollow conical body has a balanced construction to withstand at least 14,000 rpm when the conical body is coupled to a rotational apparatus.
Item 18 is the applicator of item 1, wherein the at least one outlet includes a first outlet having an outlet direction that is angled to eject the composition toward the interior surface of the hollow conical body, the outlet direction forming an angle greater than ninety degrees relative to an input direction along which the composition enters the flow diverter.
Item 19 is the applicator of item 1, wherein the flow region includes a flow zone having two portions, each portion bounded by a circumference of the hollow conical body at the holes closest to the narrow end and the first, second, third, and fourth inclined sides, and a ratio of surface area of the first holes and surface area of the flow zone is between 3:50 and 1:50.
Item 20 is the applicator of item 1, wherein the at least one outlet has a diameter based on the flow rate of the composition.
Item 21 is the applicator of item 1, wherein the at least one outlet has a diameter of at least 3.97 mm.
Item 22 is a method comprising:
providing the applicator of item 1;
feeding a composition to the flow diverter;
ejecting the composition from the at least one outlet to collect on the interior surface of the hollow conical body; and
rotating the hollow conical body so that the collected composition flows over the flow region toward the plurality of holes and sprays outwardly from the hollow conical body through at least two of the plurality of holes.
Item 23 is the method of item 22, further comprising:
moving the applicator longitudinally along the pipe during the feeding, ejecting, or rotating.
Item 24 is the method of item 22 wherein the at least one outlet is three outlets, and the composition is ejected from each of the three outlets.
Item 25 is the method of item 24, wherein the three outlets are arranged equidistant from each other.
Item 26 is the method of item 22, wherein rotating the hollow conical body comprises driving a motor that couples to the hollow conical body through a stabilizer.
Item 27 is the method of item 22, wherein the sprayed composition forms a coating on an interior surface of the pipe, the composition coating having a thickness of at least 1 mm.
Item 28 is the method of item 22, wherein the flow region includes a composition distribution zone proximate the narrow end of the hollow conical body, and wherein the ejected composition collects selectively at the composition distribution zone before flowing over a remainder of the flow region to enhance uniformity of the composition flow.
Item 29 is an apparatus comprising:
an input tube along a first axis having a first diameter and an opening at a proximate end; and
an outlet portion having a second diameter and arranged at the distal end of the input tube with a domed end transverse to the first axis, the outlet portion comprising at least two outlets arranged perpendicular to the first axis.
Item 30 is the apparatus of item 29, wherein the proximate end of the input tube is threaded.
Item 31 is the apparatus of item 30, wherein the apparatus is manually attached to a composition coating applicator.
Item 32 is the apparatus of item 29, wherein the at least two outlets each includes an outlet surface that is angled, the outlet surface angle forming an angle greater than ninety degrees relative to the first axis.
Unless otherwise indicated, all numbers expressing quantities, measurement of properties, and so forth used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that can vary depending on the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present application. Not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, to the extent any numerical values are set forth in specific examples described herein, they are reported as precisely as reasonably possible. Any numerical value, however, may well contain errors associated with testing or measurement limitations.
Various modifications and alterations of this disclosure will be apparent to those skilled in the art without departing from the spirit and scope of this disclosure, and it should be understood that this disclosure is not limited to the illustrative embodiments set forth herein. The reader should assume that features of one disclosed embodiment can also be applied to all other disclosed embodiments unless otherwise indicated. It should also be understood that all U.S. patents, patent application publications, and other patent and non-patent documents referred to herein are incorporated by reference, to the extent they do not contradict the foregoing disclosure.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/076542 | 12/19/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/105630 | 7/3/2014 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2428292 | Queen | Sep 1947 | A |
| 4216738 | Muta | Aug 1980 | A |
| 5419496 | Novak, Jr. | May 1995 | A |
| 6730353 | Robinson | May 2004 | B2 |
| 6969427 | Noles, Jr. | Nov 2005 | B1 |
| 6986813 | Davis | Jan 2006 | B2 |
| 7189429 | Robinson | Mar 2007 | B2 |
| 7338687 | Davis | Mar 2008 | B2 |
| 7591901 | Weisenberg | Sep 2009 | B1 |
| 20120058264 | Filou | Mar 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 0145266 | Jun 1985 | EP |
| 1335550 | Aug 1963 | FR |
| 61293571 | Dec 1986 | JP |
| 2010-274200 | Sep 2010 | JP |
| 2010-274200 | Dec 2010 | JP |
| 2009-0008797 | Jan 2009 | KR |
| 2305011 | Aug 2007 | RU |
| 1297932 | Mar 1987 | SU |
| WO 2012-161774 | Nov 2012 | WO |
| WO 2014-105630 | Jul 2014 | WO |
| Entry |
|---|
| International Search Report for PCT International Application No. PCT/US2013/076542 mailed on Apr. 16, 2014, 3 pages. |
| Russian Search Report for Application No. 2015126455, dated Aug. 25, 2016, 2pgs. |
| Number | Date | Country | |
|---|---|---|---|
| 20150367359 A1 | Dec 2015 | US |
