High-Point Vent System

FIELD OF THE INVENTION

[0001] The present invention relates generally to high-point vent systems for gas and liquid pipe networks and, in particular but not exclusively, to a high-point vent system that includes a redundant check valve subsystem.

BACKGROUND

[0002] Coal Seam Gas (CSG) gathering systems commonly use high density polyethylene (HDPE) pipe for gas and water flow lines. Gas and water is typically extracted from multiple wells where gas and water is separated either “down hole” or at the surface through a separator system. The gas and water is then distributed through a gathering network, which is generally a complex infrastructure of polyethylene (PE) pipelines, valves, fabricated risers and manifolds. Finally, the network delivers gas to a gas compression station and water to a water pond or treatment plant.

[0003] Gathering networks can often have problems with plugging, where gas and/or water cannot pass through the network’s pipes. Efforts to avoid such problems include the installation of low point drains (LPD's) and high- point vents (HPV’s), which are intended to remove, respectively, water plugs at low points on gas lines, and gas pockets at high points on water lines.

[0004] However, the CSG industry often sources “off the shelf” steel vents from the water industry for use as high-point vents, which steel vents suffer from several disadvantages. First, coal fines, clay deposits and construction debris (e.g., swarf) can cause blockages on smaller bore piping of conventional vents, leading to loss of containment and the flow of water out of the vent. Second, water associated with CSG applications is generally highly saline, leading to significant corrosion problems on steel components.

[0005] Further, the highly saline water associated with CSG applications is generally considered to be an environmental pollutant relative to neighbouring properties, such as farmland, and thus the leakage of such water onto neighbouring properties can be problematic. In particular, the failure of high point vents of the prior art, due for example to clogging or corrosion, can often lead to failed seals in the vents and the leakage of saline water into the surrounding environment.

[0006] There is therefore a need for an improved high-point vent system.

OBJECT OF THE INVENTION

[0007] It is an object of the present invention to overcome and/or alleviate one or more of the disadvantages of the prior art or provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION

[0008] In a first aspect, although it need not be the only or the broadest aspect, the invention resides in a high-point vent system, comprising: a housing defining a central cavity; a filter that extends across the central cavity; a float positioned in the central cavity; a float rod having a lower end and an upper end, the lower end of the float rod connected to the float and the upper end of the float rod connected to a seal; and a manifold connected to the housing and having an input end and an output end, wherein the input end defines a seal orifice that is positioned adjacent to the seal. [0009] Preferably, the system further comprises a check valve subsystem connected to the output end of the manifold.

[0010] Preferably the filter comprises a filter basket that receives the float.

[0011] Preferably, the check valve subsystem comprises two check valves, a gas valve for preventing gas from entering the system, and a liquid valve for preventing liquid from exiting the system.

[0012] Preferably, the gas valve comprises a first check ball that is moveable between an upper seat that enables gas to flow through an annular orifice and out of the system, and a lower seat against which a surface of the check ball seals.

[0013] Preferably, the liquid valve comprises a second check ball that is moveable between a lower seat that enables gas to flow through an exit orifice and out of the system, and an upper seat against which a surface of the check ball seals, sealing the exit orifice.

[0014] Preferably, the second check ball is buoyant in water.

[0015] Preferably, the first check ball and the second check ball are separated by an element having an upper curved surface for receiving the second check ball, and a lower curved surface for receiving the first check ball, whereby, in use, when gas is exiting the system through the manifold, the first check ball rests against the lower curved surface and the second check ball rests against the upper curved surface.

[0016] Preferably, the first check ball and the second check ball are separated by an element that provides an annular passage for flow around the second check ball to prevent flow from gas lifting the second check ball. [0017] Preferably, the system further comprises a reverse flush subsystem connected to the housing.

[0018] Preferably, the reverse flush subsystem comprises a first valve connected to a lower end of the housing, and a second valve connected to an upper end of the housing.

[0019] Preferably, the system further comprises a third valve connected to the housing above the second valve.

[0020] Preferably, the second valve is connected to a flushing pipe that extends through the housing below the filter, and the third valve is connected to a flushing pipe that extends through the housing above the filter.

[0021] Preferably, the seal comprises a rubber-like element that is received in a recess on the upper end of the float rod.

[0022] Preferably, the rubber-like element seals the seal orifice of the manifold, and a diameter of the seal orifice is at least an order of magnitude smaller than a diameter of the central cavity.

[0023] Preferably, each of the housing, float and filter is cylindrical.

[0024] Preferably, the housing comprises a plurality of longitudinal sections that are connectable to each other, using threaded joints or other connectors.

[0025] Preferably, a first threaded joint enables the manifold to be threadably removed, exposing the seal.

[0026] Preferably, a second threaded joint, when disconnected, enables removal of the filter and the float. [0027] Preferably, the filter, float, float rod and manifold are all removably connected to a stub flange positioned at a top end of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention are described below by way of example only with reference to the accompanying drawings, in which:

[0029] FIG. 1 is a cross sectional view of a typical high-point vent according to the prior art.

[0030] FIG. 2 is a side view of a high-point vent system, according to some embodiments of the present invention, including external valves of a reverse flush subsystem.

[0031] FIG. 3 is a cross sectional view of the cylindrical housing of the high-point vent system of FIG. 2.

[0032] FIG. 4 is a cross sectional close up view of a top end of the high- point vent system of FIG. 2, including the check valve subsystem.

[0033] FIG. 5 is a side perspective view of a high-point vent system according to an alternative embodiment of the present invention.

[0034] FIG. 6 is a side of the system of FIG. 5.

[0035] FIG. 7 is a sectional side view of section AA from FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0036] The present invention relates to an improved high-point vent system. Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.

[0037] In this patent specification, adjectives such as first and second, inside and outside, above and below, longitudinally and transverse, top and bottom, upper and lower, rear, front and side, etc., are used solely to define one element or method step from another element or method step without necessarily requiring a specific relative position or sequence that is described by the adjectives. Words such as “comprises” or “includes” are not used to define an exclusive set of elements or method steps. Rather, such words merely define a minimum set of elements or method steps included in a particular embodiment of the present invention.

[0038] FIG. 1 is a cross sectional view of a typical high-point vent 100 according to the prior art. The vent 100 includes a housing 105, a float 110, a vent valve 115, a vent 120, and a “Y” strainer 125. The materials used in the construction of the vent 100 are primarily metallic, and the design is subject to numerous operational disadvantages. The disadvantages include corrosion of metallic parts, fouling or blocking of the vent valve 115, a loss of function at angles significantly away from the vertical, difficulty and expense required for maintenance, and a low service life and difficult to clean strainer mechanism.

[0039] According to one aspect, the present invention is defined as a high- point vent system that overcomes many of the disadvantages associated with the typical high-point vent 100 of the prior art. A high-point vent system of the present invention comprises: a housing defining a central cavity; a filter that extends across the central cavity; a float positioned in the central cavity; a float rod having a lower end and an upper end, the lower end of the float rod connected to the float and the upper end of the float rod connected to a seal; a manifold connected to the housing and having an input end and an output end, wherein the input end defines a seal orifice that is positioned adjacent to the seal.

[0040] Advantages of embodiments of the present invention include a more robust high-point vent system that is more resistant to corrosion and that can operate reliably in harsh conditions.

[0041] Also, while allowing gas to be freely vented from the high-point vent, redundant sealing features of some embodiments of the present invention ensure that saline water or other liquid pollutants cannot escape from the high-point vent.

[0042] Further advantages of some embodiments of the present invention include a high-point vent system that can operate reliably at angles significantly away from the vertical.

[0043] Still other advantages of some embodiments include a system that can be efficiently cleaned and flushed to enable an extended working life.

[0044] Yet other advantages of some embodiments of the present invention include a system in which all vital components are easily accessible for cleaning, maintenance or replacement.

[0045] Those skilled in the art will appreciate that all of the above advantages are not necessarily present in all embodiments of the present invention.

[0046] FIG. 2 is a side view of a high-point vent system 200, according to some embodiments of the present invention. The system 200 includes a cylindrical housing 205 that is bolted to a stub flange 210 of a typical industrystandard T-junction pipe 212 extending up from a main pipeline 215, which pipe 212 includes a valve 222. The main pipeline 215 is shown buried below a ground level 220 and, for example, is part of a CSG gathering network.

[0047] The system 200 includes a reverse flush subsystem, as described in detail below, having a first valve 225 connected to a lower end of the housing 205, a second valve 230 connected to an upper end of the housing 205, and a third valve 235 connected to the housing 205 above the second valve 230.

[0048] FIG. 3 is a cross sectional view of the cylindrical housing 205 of the system 200. As shown, the housing 205 defines an interior central cavity 300 that extends longitudinally through the length of the housing 205, allowing gas to be freely vented from the system 200.

[0049] A cylindrical filter 305 in the form of a longitudinal basket is fixed in the cavity 300, and enables filtering and removal of debris, sludge, swarf or other waste from any fluid flowing through the cavity 300. For example, the filter 305 can comprise a thin layer of a polymer or non-corrosive metallic mesh material.

[0050] A float 310 is received inside the basket of the filter 305, and an upper end of the float 310 is connected to a float rod 315 that extends upward and out of a top of the housing 205.

[0051] Lugs 320 include through-holes that receive bolts 325, enabling longitudinal sections, including an upper section 327 and lower section 328, of the housing 205 to be bolted together. Separating the sections 327, 328 of the housing 205 enables easy access to the filter 305 and float 310 for purposes of cleaning and/or maintenance. The upper section 327 defines a settling chamber 329 that enables additional filtering of particulates that may have passed through the filter 305.

[0052] A manifold 330 and check valve subsystem 335 are connected to a top end of the housing 205, and enable effective prevention of both the entrance of gas into the high-point vent system 200 through the manifold 330, and the exit of water or other liquid out of the high-point vent system 200 into the surrounding environment.

[0053] In operation, undesirable gas is able to flow freely from a main pipeline 215 and escape from the high-point vent system 200. However, if liquid such as saline water rises from the pipeline 215 and into the central cavity 300, the float 310 will be buoyed upward by the water and force closure of the manifold 330. Further, if for some reason the float 310 fails to function properly and liquid escapes through a top of the manifold 330, then the check valve subsystem 335 functions as a redundant “back up” sealing mechanism and prevents the liquid from escaping out the top of the vent system 200. Further details concerning operation of both the float 310 and the redundant check valve subsystem 335 are provided below.

[0054] FIG. 4 is a cross sectional close up view of the top end of the high- point vent system 200, including the check valve subsystem 335. As shown by the arrow 340, escaping gas is enabled to flow out of the interior central cavity 300 through an annular gap 400 defined by a top of the housing 205 and the float rod 315. The escaping gas then flows upward to a chamber 405 below the manifold 330.

[0055] A lower end of an extension 410 of the float rod 315 is threaded into the top of the float rod 315, and an upper end of the extension 410 defines a recess that receives a rubber-like seal 415. The rubber-like seal 415 can be secured in the recess using, for example, a press fit, small barbs on the sides of the recess, and/or adhesive.

[0056] For venting gas, the manifold 330 includes a small central orifice 420 extending through the manifold 330, and a top surface of the rubber-like seal 415 is able to seal against a lower end of the central orifice 420. By limiting a diameter of the central orifice 420, such as to below 3 mm, any force from a vacuum inside the central orifice 420 that could cause the rubber-like seal 415 to stick against the bottom surface of the manifold 330, and thus prevent opening/unsealing of the orifice 420, is reduced. In operation, that enables a weight of the float 310 and float rod 315 to reliably move the rubber seal 415 downward to open or unseal the central orifice 420 in the manifold 330, and allow gas to escape upward through the orifice 420. Such reliable operation of the rubber-like seal 415 occurs even when the high-point vent system 200 is installed at angles significantly away from the vertical.

[0057] As shown in FIG. 4, various longitudinal sections of the system 200 are removably connected together using threaded joints 400, which enables easy access to the interior of the system 200 for cleaning and maintenance purposes.

[0058] The check valve subsystem 335 is connected to the upper end (gas output end) of the manifold 330. The subsystem 335 includes a gas valve 430 for preventing gas from entering the system 200, and a liquid valve 435 for preventing liquid from exiting the system 200. The gas valve 430 comprises a check ball 440 that is moveable between an upper seat that enables gas to flow through an orifice 443 and out of the system 200, and a lower seat 445 against which a surface of the check ball 440 seals and effectively closes the orifice 443.

[0059] The liquid valve 435 comprises a check ball 450 that is moveable between a lower seat that enables gas, but not liquid, to flow through an exit orifice 455 and out of the system 200, and an upper seat 460 against which a surface of the check ball 450 seals, effectively closing the exit orifice 455 to liquid such as saline water. The check ball 450 is buoyant in water, thus if water escapes through the manifold 330 such as through a failure of the rubber seal 415, then the check ball 450 floats into the upper seat 460 and prevents the water escaping from the high-point vent system 200.

[0060] The check balls 440, 450 are separated by an element 465 having an upper curved surface for receiving the check ball 450, and a lower curved surface for receiving the check ball 440. In normal use, when gas is exiting the system 200 through the manifold 330, the check ball 440 is pushed upward by the gas and rests against the lower curved surface of the element 465, while the check ball 450 is pulled downward by gravity and rests against the upper curved surface of the element 465. Element 465 integrates flow passages that direct flow annularly around the check ball 450 such that the check ball 450 is not lifted by the gas flow. The ball 450 is thus only lifted by floating in a liquid, should the chamber in which it resides fill with water.

[0061] Referring again to the reverse flush subsystem illustrated in FIG. 2, a self-contained pressurised water delivery and water recovery system can be connected by hoses to the valves 225, 230, 235. For example, such a water delivery and recovery system can be transported by truck throughout a CSG gathering network, enabling the periodic maintenance of numerous high-point vent systems 200 installed in the CSG gathering network. The reverse flush subsystem enables the high-point vent system 200 to be quickly flushed clean of debris such as swarf, and without resulting in the spillage of any saline wastewater onto the ground surrounding the vent system 200.

[0062] For example, the valve 230 can be used as a pressurised water entrance point to the cavity 300, while the lower valve 225 functions as a pressurised water and debris exit point. Water entering the valve 230 will generally wash down an outer surface of the filter 305. Alternatively or in addition, the valve 235 can be used as a pressurised water entrance point to the cavity 300, while either the valve 230 or the lower valve 225 functions as a pressurised water and debris exit point. Water entering the valve 235 will flow backwards through the filter 305 and reverse flush debris away from the filter 305.

[0063] FIG. 5 is a side perspective view of a high-point vent system 500, according to an alternative embodiment of the present invention. The system 500 is similar to the system 200; however, the upper section 327 of the housing 205 has been removed, and check valve subsystem 335 is not included. The system 500 includes a cylindrical housing 505 that is also bolted to a stub flange 210 of a typical industry-standard T-junction pipe 212 extending up from a main pipeline 215, which pipe 212 includes a valve 222. A manifold 530, which is similar to the manifold 330, is attached to a top end of the housing 505. [0064] FIG. 6 is a side of the system 500. A valve 533 can be used as a pressurised water entrance point to a cavity 700 inside the housing 505, while a lower valve 525 functions as a pressurised water and debris exit point.

[0065] FIG. 7 is a sectional side view of section AA from FIG. 6 of the system 500. The cavity 700 houses a cylindrical filter 705, a float 710, and a float rod 715. The float rod 715 connects to a valve in the manifold 530. Because there is no upper section 327, and thus no separate settling chamber 329 positioned above the filter 705, the filter 705 and float rod 715 can be further elongated to enable additional settling of particles inside of the filter 705.

[0066] As shown the hardware comprising the filter 705, float 710, float rod 715 and manifold 530 are all removably connected to a stub flange 720 positioned at the top of the housing 505 via bolts 725. That enables easy installation of such hardware and convenient access to such hardware for purposes of maintenance and/or cleaning. Further, such an arrangement enables convenient retrofitting of such hardware to an existing housing 505.

[0067] Those skilled in the art will appreciate that various components of embodiments of the present invention can be made of various materials and as various integrated or non-integrated designs.

[0068] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. Numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.