Patent Grant
9976366
This application is a National Stage Application of International Application No. PCT/IB2014/064169, filed 1 Sep. 2014, which claims benefit of Serial No. TO2013A000722, filed 6 Sep. 2013 in Italy and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.
The present invention relates to a valve assembly for drilling mud circulation and to drilling elements, such as, for example, a drill pipe, a tool joint, a sub, with which said valve assembly can be associated.
Said valve assembly is adapted to be associated with a radial aperture in hydraulic communication with an axial duct comprised in the drilling elements with which said valve assembly is associated. The valve assembly according to the present invention comprises at least two radial valves for creating a double barrier for closing a radial aperture during all wellbore drilling steps.
It is known to those skilled in the art that drilling mud has to be circulated through a drill bit located at the end of a series of drilling elements, at the bottom of the well of in proximity thereto, also during the steps of inserting or removing the drill pipes, for the purpose of preventing the uncovered hole from being damaged. In fact, pressure variations that occur at the bottom, which are due to the fact that the pump is in operation while drilling and is then turned off for inserting or removing the pipes, may cause landslides and/or entry of fluids into the wellbore. Circulation of the mud through the bit during the steps of inserting or removing the pipes takes place thanks to a drilling element that, in addition to comprising a through hole extending along the longitudinal axis, also comprises a radial aperture that allows drilling mud to flow in when it cannot be directly pumped through the longitudinal hole. This problem is particularly felt for critical wells, such as, for example, deep, deviated, horizontal and extended-reach wells.
For better performance and operational safety, it is in fact necessary to keep the well bottom pressure constant at desired levels.
Prior-art drilling elements comprise safety valves or valve assemblies that both ensure the necessary safety during the various operating steps and appropriately direct the mud flows to avoid undesired backflows.
Drilling elements are known which comprise valve assemblies wherein a single-barrier valve is arranged at the radial aperture, and a further axial valve is arranged in correspondence to the through hole of the drilling element itself. In addition, in order to ensure that the radial aperture is closed properly, in particular during the drilling steps, a removable plug is inserted in correspondence to the radial aperture. Said removable plug is fixed into a suitable threaded seat comprised in the inner wall of the radial aperture, upstream of said safety valve with respect to the direction of the mud flow entering through said radial aperture. One example of such a drilling element is illustrated in patent document U.S. Pat. No. 3,298,385.
It is known that, during the steps of removing or inserting one or more drill pipes, the radial valve follows the following operating sequence:
The radial aperture is located at such a height as to be easily accessible to an operator. This means that an undesired leak of high-pressure drilling mud through said radial aperture will be directed towards the operators, thus being dangerous.
The above-mentioned patent document does not provide a double barrier in correspondence to the radial aperture during the pipe insertion and removal step, which step requires the presence of operators near the working area. This partial lack of protection arises right after the removable safety plug has been removed, and this may cause important safety problems for the people working in proximity to the valve during the steps of opening and closing the radial aperture. As a matter of fact, following the removal of the safety plug the radial aperture is only kept closed by one shutter. Should said radial valve fail, undesired leakage of mud might occur, causing considerable problems. The lack of safety of such devices is due to the very necessity of removing the protection plug and relying for an indefinite period of time on the radial valve alone for keeping said aperture closed, with circulation pressures that may be in excess of 34474 kpa or even close to 51711 kpa. In such a situation, there will only be one radial valve to prevent an undesired leakage of drilling mud in a direction that might be dangerous for the operators working on the drill floor, near the drill pipes.
Normally said radial valve is a flap valve, which, in case of failure, will not be able to hermetically seal the radial aperture, through which mud could exit due to the pressures involved.
From patent application US2011203670 valve elements are also known which comprise a spherical valve that includes more than one through holes formed inside the spherical shutter, so that it is possible to selectively close and open the radial aperture and the axial longitudinal hole of the drilling element with which said valve element is associated.
From a purely theoretical viewpoint, such a solution appears to be safer than the above-discussed case, but in practice, due to the use of a spherical valve, it does not ensure proper closing and opening of both the radial aperture and the axial longitudinal hole of the drilling element, especially when high pressures are involved.
The present invention aims at solving the above-described technical problems by providing a valve assembly for selectively opening and closing a radial aperture on a drilling element at operating pressures up to 51711 kpa, which provides a double barrier in any operating condition of the drilling rig, thus improving safety during the various operating steps, especially during the steps of inserting and removing drill pipes.
One aspect of the present invention relates to a valve assembly comprising two barriers.
A further aspect of the present invention relates to a drilling element comprising a valve assembly according to the present invention.
The features and advantages of the valve assembly and of the drilling element with which it is associated will become apparent from the following exemplificative and non-limiting description of several equivalent embodiments thereof and from the annexed drawings, wherein:
With reference to the above-listed Figures, valve assembly 2 according to the present invention is adapted to selectively open and close a radial aperture 84 provided on a drilling element 8 for drilling mud circulation.
For the purposes of the present invention, the term drilling element 8 refers to any substantially cylindrical device used for drilling an extraction well, which can be inserted into the well itself and which comprises an axial longitudinal hole 82 and a radial aperture 84, e.g. as shown in
Valve assembly 2 according to the present invention comprises a valve body 3, which in turn comprises an inlet aperture 3A and an outlet aperture 3C. Said valve body 3 further comprises a duct 3B for putting said apertures 3A, 3C in communication with each other, thereby defining a mud path “p”.
The term mud path “p” refers to the path followed by the drilling mud as it is fed in through radial aperture 84 of drilling element 8, when the same valve assembly 2 is associated with drilling element 8, as is known to a man skilled in the art.
Valve assembly 2 according to the present invention comprises at least two movable shutters 4, 6 arranged in cascade along the direction of the mud path “p”, thus forming at least a double barrier.
The exemplary and non-limiting embodiments of valve assembly 2 described below and illustrated in the drawings preferably comprise two shutters 4, 6. In equivalent non-limiting embodiments, said shutters may be more than two, while nevertheless providing the same technical effect.
Preferably, said at least two shutters 4, 6 can move with respect to said valve assembly 2, in particular with respect to valve body 3, but they cannot be removed from valve body 3. Said at least two shutters 4, 6 are movable and stay operationally connected to the valve body, preferably always and constantly over time.
Preferably, in at least one operating configuration said at least two shutters 4, 6 are arranged along one same first axis “X”, preferably substantially parallel to the direction of mud path “p”, or at least along the same direction.
Preferably, said first axis “X” corresponds to the longitudinal axis of radial aperture 84 comprised in drilling element 8.
Preferably, the shutters comprised in valve assembly 2 according to the present invention form normally-closed valves.
The term normally-closed valve refers to a valve intended for staying closed, thus preventing the passage of a fluid through the duct 3B of the valve body 3; the same valve will only open, thereby allowing the passage of a fluid, if appropriately operated.
In the embodiments shown in the annexed drawings, valve assembly 2 according to the present invention comprises two shutters 4, 6. In particular, it comprises a first shutter 4 and a second shutter 6. Said first shutter 4 is arranged downstream, along mud path “p”, with respect to a second shutter 6.
More in detail, said first shutter 4 is arranged in proximity to outlet aperture 3C of valve body 3, preferably in correspondence thereto, and said second shutter 6 is arranged in proximity to said inlet aperture 3A of valve body 3. In the embodiments of
Said second shutter 6 can move with respect to valve assembly 2, in particular with respect to valve body 3, while still remaining operationally connected to valve assembly 2, in particular to valve body 3. In particular, said second shutter 6 is movable, but it remains operationally connected to said valve body 3. In all four exemplary and non-limiting embodiments, the second shutter 6 can be moved while still remaining in the proximity of inlet aperture 3A and operationally connected thereto, i.e. second shutter 6 cannot be removed from valve assembly 2. In particular, there is at least one retaining element 62 that prevents the second shutter 6 from being completely removed or separated from valve body 3.
The second shutter 6 can be operated automatically, e.g. via an automatic or semi-automatic opening element (not shown).
For the purposes of the present invention, the term shutter operation means the action of switching between the different operating configurations of the shutter.
In general, said second shutter 6 comprises at least one hooking element 7 through which said opening element can appropriately activate or deactivate said second shutter 6.
The actuation of said second shutter 6 occurs through a rotational and/or translational movement, e.g. a purely rotational movement, a rotational-translational movement, or a purely translational movement. Upon every movement of said second shutter, the latter always remains operationally connected to valve body 3.
In equivalent, non-limiting embodiments, the actuation of said second shutter 6 is achieved through a complex kinematic movement, which can however provide the same technical effects.
In general, said second shutter 6 comprises a retaining element 62 that allows the second shutter 6 to move between an active or closed configuration, in which it obstructs duct 3B and prevents the passage of drilling mud, and an inactive or open configuration, in which it allows the passage of drilling mud.
Said valve assembly 2 comprises a fastening portion 22 to be fastened to or associated with a drilling element 8. In the embodiments shown in
Fastening portion 22 is adapted to engage with a complementary threaded portion on the internal edges of the radial aperture 84 of a drilling element 8.
In the embodiments shown in
In general, said first shutter 4 is preferably a flap valve.
In particular, said first shutter 4 rotates about an axis of rotation “Y”, perpendicular to said first axis “X”, along which said first and second shutters 4, 6 are substantially arranged.
Said first shutter 4 is connected to a first retaining element 42, which allows the first shutter 4 to move correctly between the two operating configurations. Preferably, said retaining element 42 retains said first shutter 4 in a closed configuration. In the preferred embodiment, said retaining element 42 is a hinge, more preferably a hinge comprising an elastic element, e.g. a coil spring.
Said axis of rotation “Y” may be parallel to the longitudinal axis of axial longitudinal hole 82 comprised in drilling element 8 with which said valve assembly 2 is associated. In the preferred embodiment, which is however non-limiting, said axis of rotation “Y” is perpendicular to the longitudinal axis of axial longitudinal hole 82 comprised in drilling element 8 with which said valve assembly 2 is associated, as shown in
The following will describe in detail the technical features and principles of operation of three exemplary and non-limiting embodiments of the radial valve.
Equivalent and/or hybrid embodiments should be considered to fall within the protection scope of the present invention.
Said first and second orifices are preferably shaped like a circumference sector, e.g. a shown in
The rotation of said second shutter 6 allows said first orifices 31A to be at least partially made to match said second orifices 60, thereby creating a mud path “p” through which drilling mud can flow.
In order to allow the drilling mud to flow in a radial direction relative to a drilling element 8 equipped with valve assembly 2 according to the present invention during the feeding steps, second shutter 6 is turned with respect to the portion of valve body 3 that houses the same second shutter 6. The rotation of said second shutter 6 is such that at least one intake passage or port will be opened. The mud passage section through inlet aperture 3A of valve body 3 is visible in
The rotation of said second shutter 6 is actuated by an automatic or semi-automatic opening device.
The first shutter 4, instead, is of the flap type and is normally closed through the effect of a preload of an elastic element, such as a coil spring, comprised in the first retaining element 42, in particular a hinge. Said shutter abuts against a jacket 31C corresponding to outlet aperture 3C of valve body 3.
During the radial feeding step, said first shutter 4 opens through the effect of the thrust exerted by the drilling mud as it flows through.
The axis of aperture of the first shutter 4 is vertical and parallel to the longitudinal axis of through hole 82 of drilling element 8.
At the end of the step of feeding mud through valve assembly 2 located at radial aperture 84 of drilling element 8, the absence of mud will cause the first shutter 4 to close again in abutment with jacket 31C, corresponding to outlet aperture 3C of valve body 3, through the effect of the elastic means, e.g. a coil spring. Subsequently, the automatic or semi-automatic opening device will rotate the second shutter 6 again to reclose the paths or ports previously created, thus returning into the initial closed configuration. The closing of said ports is due to the fact that said first orifices 31A will no longer match said second orifices 60, which are movable relative to said first orifices 31A.
The rotation of said second shutter 6 is due to an opening element that, by engaging with at least one clutching element 7 comprised in said second shutter 6, can rotate between the two operating configurations of said second shutter 6, while still keeping said shutter operationally connected to the valve body.
Preferably, said at least one clutching element 7 is arranged externally to valve body 3, so that it can interact with said opening device, as shown by way of example in
More preferably, there are four of said clutching elements 7 equally spaced along a circumference and alternated with said second orifices 60 along the same circumference, as clearly shown in
The rotational-translational movement of said second shutter 6 allows the generation of a mud path “p” through which drilling mud can flow.
Said housing 61 cooperates with said second retaining element 62 in such a way as to allow the rotation of the second shutter 6, by allowing the second end of retaining element 62 to slide along the perimeter of housing 61, preferably in a groove. The same housing 61 cooperates with said second retaining element 62 in such a way as to allow the translation of the second shutter, holding the second end of the retaining element and thus defining the maximum translational travel of the second shutter 6, as clearly shown in
In order to allow the drilling mud to flow in a radial direction relative to a drilling element 8 equipped with valve assembly 2 according to the present invention during the feeding steps, the second shutter 6 is turned with respect to the portion of valve body 3 that houses the same second shutter 6, and is then extracted, without however being removed, from said seat, e.g. by making a translational movement, preferably along said axis “X”, so as to open at least one intake passage or port. The mud passage section through inlet aperture 3A of valve body 3 is visible in
The rotational-translational movement of said second shutter 6 is actuated by an automatic or semi-automatic opening device.
In this embodiment as well, the first shutter 4 is of the flap type and is normally closed, e.g. through the effect of a preload of an elastic element, such as a coil spring, comprised in the first retaining element 42, in particular a hinge. Said first shutter is normally closed and abuts against a jacket 31C corresponding to outlet aperture 3C of valve body 3.
During the radial feeding step, said first shutter 4 opens through the effect of the thrust exerted by the drilling mud as it flows through.
The axis of aperture of the first shutter 4 is vertical and parallel to the longitudinal axis of through hole 82 of drilling element 8.
At the end of the step of feeding mud through valve assembly 2 located at radial aperture 84 of drilling element 8, the absence of mud will cause the first shutter 4 to close again in abutment with jacket 31C, corresponding to outlet aperture 3C of valve body 3, through the effect of the elastic means, e.g. a coil spring. Subsequently, the automatic or semi-automatic opening device will translate and rotate the second shutter 6 again to reclose the paths or ports previously created, thus returning into the initial closed configuration. The closing of said ports is caused by the obstruction of inlet aperture 3A of valve body 3 by the second shutter 6, after it has been translated and sealingly tightened by its rotation.
The rotational-translational movement of said second shutter 6 occurs thanks to an opening element that, by engaging with at least one clutching element 7 comprised in said second shutter 6, can move said second shutter 6 between the two operating configurations. In particular, said opening element can turn said second shutter 6 and also extract the second shutter 6, without however removing it, from its seat, e.g. by acting upon said at least one retaining element 62 or by exerting a translation force on the second shutter 6 itself.
Preferably, said at least one clutching element 7 is arranged externally to valve body 3, so that it can interact with said opening device, as shown by way of example in
More preferably, there are four of said clutching elements 7, equally spaced along a circumference, as shown in
Said at least one retaining element 62 preferably comprises an elastic means 622 adapted to hold said second shutter 6 in a desired configuration, e.g. closed.
In the illustrated embodiment, said elastic means 622 acts upon said retaining element 62 in a manner such that, in the absence of any external forces, in particular for extracting the second shutter 6, the same second shutter 6 will obstruct inlet aperture 3A of valve body 3 thanks to a preload of said elastic means 622. This feature significantly improves the efficiency of the closing step and the safety of valve assembly 2 according to the present invention. Said elastic means 622 is preferably a coil spring.
Said shutter 6 translates or rotates and translates in a housing 61, preferably an interspace. Said housing 61 is formed in valve body 3 or between the outer wall of valve body 3 and a wall of a drilling element 8. As shown in the annexed drawings, particularly in
Said second shutter 6 comprises at least one second orifice 60, preferably only one having a circular shape.
In the present embodiment, said at least one second retaining element 62 is a guide, e.g. made or formed on the second portion 35 of valve body 3, with which hooking element 7 engages, the latter being rigidly fixed to said second shutter 6, as shown in
Said second retaining element 62 is adapted to guide said hooking element 7 in a manner such that it will translate or rotate and translate about an axis, e.g. perpendicular to said first axis “X”, in order to allow the second shutter 6 to translate or rotate and translate along an axis substantially parallel to the axis of rotation “Y”. Said translation or rotation-translation allows the second shutter 6 to clear inlet aperture 3A, e.g. by exiting duct 3B, or by matching said second orifice 60 with inlet aperture 3A of valve body 3 and with duct 3B.
Said second retaining element 62 allows the second shutter 6 to make a translational or rotational-translational movement, essentially along an axis parallel to said axis of rotation “Y”. In the preferred embodiment, said second shutter 6 rotates by a predetermined angle of rotation ranging between 0 and 90°, and at the same time translates along an axis substantially parallel to said axis “Y”, thereby generating a mud path “p” that allows drilling mud to flow through.
Thanks to the translation or rotation-translation of said second shutter 6, a mud path “p” is generated through which drilling mud can flow, as shown by way of example in
The second retaining element 62 is so shaped as to allow moving hooking element 7 for the purpose of allowing the second shutter 6 to switch between the two operating configurations.
As shown in
Said two horizontal sections respectively allow the second shutter to be kept in an operating configuration, whether open or closed. The inclined section is such that it allows the second shutter 6, via hooking element 7, to translate or rotate and translate. Said retaining element defines the translational or rotational-translational travel of the second shutter 6, as clearly visible in
In order to allow the drilling mud to flow in a radial direction relative to a drilling element 8 equipped with valve assembly 2 according to the present invention during the feeding steps, the second shutter 6 is translated or rotated and translated with respect to portions 33, 35 of valve body 3 by moving substantially along said axis “Y”, so as to open at least one intake passage or port. In particular, said intake passage or port is obtained through the at least partial interface between a second orifice 60 comprised in the second shutter 6 and inlet aperture 3A and duct 3B of the valve body. The mud passage section through inlet aperture 3A of valve body 3 is visible in
The translational or rotational-translational movement of said second shutter 6 is actuated by an automatic or semi-automatic opening device.
In this embodiment as well, the first shutter 4 is of the flap type and preferably is normally closed, e.g. through the effect of a preload of an elastic element, such as a coil spring, comprised in the first retaining element 42.
All the features of said first shutter 4 described in the above embodiments will also apply to the following embodiment.
At the end of the step of feeding mud through valve assembly 2 located at radial aperture 84 of drilling element 8, the absence of mud will cause the first shutter 4 to close again in abutment with jacket 31C, through the effect of the elastic means. Subsequently, the automatic or semi-automatic opening device will translate or rotate and translate the second shutter 6 again to reclose the paths or ports previously created, thus returning into the initial closed configuration. The closing of such ports is due to the fact that, after the translational or rotational-translational movement, said second orifice 60 will no longer match inlet aperture 3A and duct 3B of valve body 3.
The translation or rotation-translation of said second shutter 6 occurs thanks to an opening element that, by engaging with at least on clutching element 7 comprised in said second shutter 6, can move said second shutter 6 between the two operating configurations. In particular, said opening element can translate or rotate and translate said second shutter 6.
Preferably, said at least one clutching element 7 is arranged externally to valve body 3, but internally with respect to the profile of drilling element 8, so that it can interact with said opening device, as clearly shown by way of example in
More preferably, said at least one clutching element 7 is only one.
The rotational-translational movement of said second shutter 6 allows the generation of a mud path “p” through which drilling mud can flow.
Said guide and said pin of the second retaining element cooperate together to allow the second shutter 6 to rotate and translate. Said guide thus defines the rotational and translational travel of the second shutter 6, as can be understood from
In order to allow the drilling mud to flow in a radial direction relative to a drilling element 8 equipped with valve assembly 2 according to the present invention during the feeding steps, the second shutter 6 is turned with respect to the portion of valve body 3 that houses the same second shutter 6, and is then extracted, without however being removed, from said seat, e.g. by making a translational movement, preferably along said axis “X”, so as to open at least one intake passage or port. The mud passage section through inlet aperture 3A of valve body 3 is visible in
The rotational-translational movement of said second shutter 6 is actuated by an automatic or semi-automatic opening device.
In this embodiment as well, the first shutter 4 is of the flap type and is normally closed, e.g. through the effect of a preload, in particular a hinge. Said first shutter 4 is normally closed and abuts against a jacket 31C corresponding to outlet aperture 3C of valve body 3.
During the radial feeding step, said first shutter 4 opens through the effect of the thrust exerted by the drilling mud as it flows through.
The axis of aperture of the first shutter 4 is perpendicular to the longitudinal axis of through hole 82 of drilling element 8 and perpendicular to said first axis “X”.
This type of first shutter 4 can be considered to be the preferred embodiment, without however being limiting in nature. This type of first shutter is preferably applicable to all other embodiments of the valve assembly previously described herein.
As shown in
Preferably, the first shutter 4 is interposed between two portions of valve body 3, in particular between a first portion 33, comprising outlet aperture 3C, and a second portion 35, comprising said inlet aperture 3A.
At the end of the step of feeding mud through valve assembly 2 located at radial aperture 84 of drilling element 8, the absence of mud will cause the first shutter 4 to close again in abutment with jacket 31C, corresponding to outlet aperture 3C of valve body 3, through the effect of said preload. Subsequently, the automatic or semi-automatic opening device will translate and rotate the second shutter 6 again to reclose the paths or ports previously created, thus returning into the initial closed configuration. The closing of said ports is caused by the obstruction of inlet aperture 3A of valve body 3 by the second shutter 6, after it has been translated and sealingly tightened by its rotation.
The rotational-translational movement of said second shutter 6 occurs thanks to an opening element that, by engaging with at least one clutching element 7 comprised in said second shutter 6, can move said second shutter 6 between the two operating configurations. In particular, said opening element can turn said second shutter 6 and also extract the second shutter, without however removing it, from its seat in valve body 3, e.g. by exerting a pulling force on the second shutter 6 itself.
Preferably, said at least one clutching element 7 is arranged externally to valve body 3, so that it can interact with said opening device, as shown by way of example in
More preferably, there are two of said clutching elements 7, equally spaced along a diametral direction, as shown in
In all embodiments, said mobile second shutter 6 always remains associated with said valve body 3, without being removed from said valve body.
Said drilling element 8 has a substantially cylindrical shape and, as aforementioned, comprises an axial longitudinal hole 82 and a radial aperture 84, with which a valve assembly 2 according to the present invention is associated.
Said drilling element may comprise an axial valve 9, located in correspondence to the axial longitudinal hole 82. Said axial valve 9 is preferably a flap valve adapted to obstruct the flow of drilling mud in an axial direction, in particular opposite to a mud circulation “f” when said valve assembly 2 is open for mud circulation through radial aperture 84, along mud path “p”. The mud circulation “f” is shown by way of example in
In the preferred embodiment, said drilling element does not include an axial valve at axial longitudinal hole 82, as shown in
Valve assembly 2 according to the present invention can operate at working pressures of 51711 kpa, with a drilling mud flow rate ranging between 3,500 and 4,000 liters per minute.
Valve assembly 2 according to the present invention and drilling element 8 with which said valve assembly 2 is associated can improve safety during the drilling process, aiming at safeguarding the people's life, the environment, and the devices used during the drilling operations.
Valve assembly 2 is applicable to any drilling element and can be used for all oil well drilling activities.
Valve assembly 2 is applicable, by way of non-limiting example, for drilling operations employing 11.4 cm, 12.7 cm, 14 cm and 14.9 cm diameter drill pipes and 16.8 cm, 17.8 cm, 18.4 cm and 19.1 cm diameter drilling elements 8.
Valve assembly 2 is also applicable, by way of non-limiting example, for drilling operations employing 6⅝″ diameter drill pipes and 20.3 cm, 21 cm and 21.6 cm drilling elements 8.
Valve assembly 2 according to the present invention allows keeping the mud flow directed as desired by the operator and prevents any backflow of drilling mud.
The possibility of ensuring continuous circulation during the drilling process and of keeping the pressure constant at the bottom of the well also during pipe changes offers the following advantages:
Valve assembly 2 according to the present invention allows the passage, within the battery of drill pipes, of one or more tools necessary for checks or interventions that might be required during the making of the wellbore, also allowing unscrewing or even cutting a drill pipe in the well.
| Number | Date | Country | Kind |
|---|---|---|---|
| TO2013A0722 | Sep 2013 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2014/064169 | 9/1/2014 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/033260 | 3/12/2015 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3298385 | Jackson et al. | Jan 1967 | A |
| 20060278434 | Calderoni et al. | Dec 2006 | A1 |
| 20100096190 | Younger et al. | Apr 2010 | A1 |
| 20110203670 | Braddick | Aug 2011 | A1 |
| 20120018229 | Leuchtenberg et al. | Jan 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 2540956 | Sep 2007 | CA |
| 2014027317 | Feb 2014 | WO |
| 2014135873 | Sep 2014 | WO |
| 2014203153 | Dec 2014 | WO |
| Entry |
|---|
| International Search Report and Written Opinion from International Application No. PCT/IB2014/064169, dated May 4, 2015. |
| International Preliminary Report on Patentability from International Application No. PCT/IB2014/064169, dated Oct. 6, 2015. |
| Number | Date | Country | |
|---|---|---|---|
| 20160222742 A1 | Aug 2016 | US |
