Patent Application
20210262580
The present invention related broadly to a flow control valve and relates particularly although not exclusively to a tank overfill protection system including a flow control valve operated by a pilot “signal” from an associated tank level sensor.
In order to save time in industrial refueling applications, flowrates over 100 litres per minute are often specified. One approach to refuel tanks is to use a pressurized tank shut off system. This system allows a tank to be refueled at atmospheric pressure until the level of fuel inside the tank trips a level sensor, and seals off the tank venting function. The tank continues filling and pressurizes until the pressure within the tank reaches a “set point” which causes the system to shut off. Repeated refueling cycles using this shut off system have the potential to cause tanks to fatigue. Additionally, manual override of pressurized tank shut off systems can introduce problems such as fuel spills and exacerbate the tank pressure. Further, the trend towards lower mass and lower cost fuel tanks onboard plant equipment such as mining vehicles has reduced the design pressure of such tanks, virtually mandating a “zero tank pressure” refueling system.
In order to address these shortcomings of pressurized tank shut off systems, an alternative “zero tank pressure” system has been developed by the applicant. This “zero tank pressure” system uses a combination of a level sensor, pilot line, and flow control valve to automatically shut off flow to the tank at a safe fill level. Operation of the flow control valve is based on a flow/no-flow condition of a pilot line connected into the flow control valve itself. This pilot line is connected to one or more level sensors which are designed to allow free flow through the pilot line until the fuel level within the tank reaches a set point. Once the set point is reached the level sensors are designed to restrict flow through the pilot line, and thereby shut the flow control valve.
International patent publication No. WO2015/103341 by Cooley discloses a flow control valve for use with a float valve and associated pilot circuit. The flow control valve is designed to be automatically shut off via the float valve/pilot circuit when the fuel level reaches an adequate fill level. The flow control valve is of a normally-closed configuration relying upon a spring to bias a valve plug closed. The valve plug reciprocates outside a guide support and together they define a pressure chamber within which the spring is contained. The control valve also includes a tubular valve plug guide along which the valve plug travels in opening and closing. The valve plug guide is in fluid communication with the pilot circuit and includes fluid apertures at the pressure chamber. The pilot circuit includes an aperture which acts as a “flow limiter” at an entrance to the control valve which provides a limited flow of fluid to the pilot circuit. On reaching an adequate fill level, the flow of bleed fluid through the pilot circuit is prevented whereby the fluid pressure in the pressure chamber increases to assist the spring in closing the valve plug.
According to a first aspect of the present invention there is provided a flow control valve comprising:
a valve body defining a fluid passageway between a fluid inlet and a fluid outlet;
a piston slidably mounted within the fluid passageway and arranged for opening and closure of the fluid outlet;
a bleed fluid cavity at least in part located within the valve body and arranged to cooperate with the piston to, under the influence of bleed fluid pressure within the bleed fluid cavity, create a force imbalance across the piston to promote closure of the fluid outlet by displacement of the piston;
a bleed fluid conduit operatively coupled to the bleed fluid cavity for bleed fluid communication between said cavity and the bleed fluid conduit;
a venturi arrangement operatively coupled to the bleed fluid conduit to reduce pressure within the bleed fluid cavity to promote evacuation of the bleed fluid from said cavity thereby opening the fluid outlet by displacement of the piston.
Preferably the valve body includes a rear valve body within which the piston is slidably mounted, said rear body including one or more radial openings which at least in part define the fluid outlet. More preferably the piston includes a peripheral wall arranged to cooperate with the radial openings of the rear body for opening and closure of the fluid outlet. Still more preferably the peripheral wall of the piston internally defines a piston chamber which at least in part forms the bleed fluid cavity.
Preferably the piston includes an axial opening through which the bleed fluid conduit passes defining an annular bleed passage between the piston and the bleed fluid conduit, said bleed passage arranged to transfer bleed fluid to or from the fluid passageway and the bleed fluid cavity. More preferably the bleed fluid conduit includes one or more apertures located within the bleed fluid cavity and arranged to provide the bleed fluid communication between the bleed fluid cavity and the bleed fluid conduit.
Preferably the valve body also includes a front valve body defining at least part of the fluid passageway including the fluid inlet, said front valve body operatively coupled to a pilot line associated with the flow control valve. More preferably the valve body also includes a connector arranged to retain the rear valve body and adapted to connect to a tank with which the pilot line is associated.
Preferably the venturi arrangement is operatively coupled to the pilot line at the front valve body and located within the fluid passageway at the front valve body. More preferably the bleed fluid conduit connects the venturi arrangement within the front valve body to the bleed fluid cavity. Even more preferably the venturi arrangement is associated with a fluid sampling orifice which samples fluid at the fluid inlet for provision at the venturi arrangement which with fluid flow through the pilot line promotes evacuation of bleed fluid from the bleed fluid cavity via the bleed fluid conduit thus reducing pressure within the bleed fluid cavity to promote displacement of the piston and opening of the fluid outlet. Still more preferably the fluid sampling orifice on restricted fluid flow through the pilot line provides sampled fluid from the fluid inlet to the bleed fluid cavity via the venturi arrangement and the bleed fluid conduit to substantially equalise fluid pressure between the fluid sampling orifice and the bleed cavity whereby the force imbalance across the piston promotes displacement of the piston and closure of the fluid outlet. In this arrangement the pilot line with which the flow control valve is associated is located outside the tank.
Alternatively the venturi arrangement is located within the bleed fluid cavity and is operatively coupled to a pilot line at the rear valve body. In this alternative embodiment the venturi arrangement is associated with a fluid sampling orifice which samples fluid at the fluid passageway for provision at the venturi arrangement which with fluid flow through the pilot line promotes evacuation of bleed fluid from the bleed fluid cavity via the bleed conduit thus reducing pressure within said bleed cavity to promote displacement of the piston and opening of the fluid outlet. In this alternative embodiment the bleed fluid conduit is adapted to operatively couple to the pilot line located inside a tank with which the flow control valve is associated.
Preferably the piston includes a cylindrical portion defined by the peripheral wall, a seating portion connected to the cylindrical portion, and a substantially conical portion connected to the seating portion. More preferably the seating portion includes a radially extending seating face configured to seat with the rear valve body on closure of the fluid outlet via the piston. Even more preferably the fluid passageway is in a downstream flow direction tapered inwardly forming an annular shoulder including a radially extending seating face within the rear valve body configured for seating closure with the seating face of the seating portion of the piston. Still more preferably the seating face of the piston is formed by an annular rebate within the seating portion of the piston. Even still more preferably the piston is designed for staged closure of the fluid outlet where initially the annular shoulder of the rear valve body axially overlaps the annular rebate of the piston and subsequently, on complete closure of the fluid opening, the seating face of the rear body contacts the seating face in the piston. Still further more preferably the seating portion of the piston has a circumferential chamfer extending radially outward from the seating face of the piston reducing its contact area with the seating face of the rear valve body assisting with operation of the piston.
Preferably the front valve body is pivotally coupled to the connector for rotational movement relative to said connector for reorientation of the front valve body for substantial alignment with the pilot line. More preferably the valve includes a clasp assembly arranged to clasp the front valve body to the rear valve body for axial securement to one another whilst permitting pivotal movement of the front valve body relative to the connector. Even more preferably the clasp assembly includes a plurality of flange segments arranged to engage the front valve body, and a plurality of clasp fasteners arranged to engage both the connector and the plurality of flange segments for axial securement of the front and rear valve bodies to one another. Still more preferably the valve body further includes one or more locking elements arranged to engage both the front valve body and the clasp assembly to pivotally secure the front valve body relative to the connector.
According to a second aspect of the invention there is provided a flow control valve comprising:
a valve body defining a fluid passageway between opposing first and second fluid openings;
a piston slidably mounted within the fluid passageway and arranged for opening and closure of the second fluid opening;
a bleed fluid cavity at least in part located within the valve body and arranged to cooperate with the piston to, under the influence of bleed fluid pressure within the bleed fluid cavity, create a force imbalance across the piston to promote closure of the second fluid opening by displacement of the piston;
a bleed fluid conduit operatively coupled to the bleed fluid cavity for bleed fluid communication between said cavity and the bleed fluid conduit;
a venturi arrangement operatively coupled to the bleed fluid conduit to reduce pressure within the bleed fluid cavity to promote evacuation of the bleed fluid from said cavity thereby opening the second fluid opening by displacement of the piston.
Preferably the valve body is operatively coupled to a pilot line associated with the flow control valve. More preferably the venturi arrangement is associated with a fluid sampling orifice which samples fluid from either the first opening or the fluid passageway for provision at the venturi arrangement wherein: i) fluid flow from the venturi arrangement and through the pilot line in one direction promotes evacuation of bleed fluid from the bleed fluid cavity via the bleed fluid conduit thus reducing pressure within the bleed fluid cavity to promote displacement of the piston and opening of the second fluid opening, and ii) fluid flow from the pilot line and through the venturi arrangement in an opposite direction also promotes evacuation of bleed fluid from the bleed fluid cavity to promote opening of the second fluid opening. Even more preferably the flow control valve is arranged for bi-directional flow when fluid flows through the pilot line occurs in either said one or the opposite direction.
According to a third aspect of the invention there is provided a tank overfill protection system comprising:
a flow control valve adapted to operatively couple to a tank to be filled with fluid, said flow control valve comprising:
a tank level sensor adapted to operatively couple to the tank, said level sensor connected to a pilot line associated with bleed fluid cavity of the flow control valve whereby the tank level sensor is arranged to detect a safe fill level within the tank and restrict bleed fluid flow through the pilot line promoting the force imbalance across the piston which is effective in displacement of the piston for closure of the fluid outlet of the flow control valve.
Preferably the tank level sensor comprises:
a valve body including a pilot inlet adapted to couple to the pilot line;
at least one pilot valve mounted to the valve body and in liquid communication with the pilot inlet;
a pilot valve actuator operatively coupled to said at least one pilot valve for its opening and closure, the pilot valve actuator including a balance member arranged to cooperate with actuator biasing means, the balance member having a specific gravity relative to liquid within the tank whereby at least part submersion of the balance member provides movement of the balance member relative to the valve body, said movement of the balance member:
i) only occurring together with the influence of the actuator biasing means;
and
ii) being effective in closure of said at least one pilot valve.
More preferably said at least one pilot valve includes at least one poppet valve having a poppet valve head connected to a valve stem arranged to be contacted by the balance member for opening of said at least one pilot valve. Even more preferably the actuator biasing means includes a pilot valve compression spring designed to provide sufficient biasing force to provide movement of the balance member relative to the valve body for:
According to a fourth aspect of the invention there is provided a flow control valve comprising:
a valve body assembly including a rear valve body defining part of a fluid passageway including a fluid outlet, said valve body assembly including a connector arranged to retain the rear valve body;
a piston slidably mounted within the fluid passageway of the rear valve body and arranged for opening and closure of the fluid outlet;
a front valve body defining at least part of the fluid passageway including a fluid inlet, said front valve body pivotally coupled to the connector for rotational movement relative to said connector for reorientation of the front valve body.
Preferably the connector is adapted to connect to a tank, and the front valve body is operatively coupled to a pilot line associated with the flow control valve. More preferably the front valve body rotationally couples to the connector for reorientation relative to the connector for substantial alignment with the pilot line.
Preferably the flow control valve includes a clasp assembly arranged to clasp the front valve body to the rear valve body for axial securement to one another whilst permitting rotational movement of the front valve body relative to the connector. More preferably the clasp assembly includes a plurality of flange segments arranged to engage the front valve body, and a plurality of clasp fasteners arranged to engage both the connector and the flange segments for axial securement of the front and rear valve bodies to one another. Still more preferably the valve body further includes one or more locking elements arranged to engage both the front valve body and the clasp assembly to rotationally secure the front valve body relative to the connector.
In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a flow control valve and a tank overfill protection system will now be described, by way of example only, with reference to the accompanying drawings in which:
In this embodiment the flow control valve 12 is connected within a tank shell 18 fitted to a tank 20. The tank 20 is unpressurised and in this example contains a liquid such as diesel. The tank 20 is filled via a nozzle 22 which connects to a receiver 24 associated with the flow control valve 12. In operation the tank level sensor 14 is designed at a safe fill level within the tank 20 to restrict flow through the pilot line 16 and automatically close the flow control valve 12 to stop filling of the tank 20 via the nozzle 22, see
In this embodiment the valve body 26 includes a rear valve body 42 within which the piston 34 is slidably mounted, the rear valve body 42 including one or more radially openings such as 44a which at least in part define the fluid outlet 32. In this example the piston 34 includes a peripheral wall 46 being shaped substantially cylindrical and arranged to i) cooperate with the radial openings such as 44a of the rear body 42 for opening and closure of the fluid outlet 32, and ii) internally define a piston chamber 48 which at least in part forms the bleed fluid cavity 36.
In this embodiment the piston 34 includes an axial opening 50 through which the bleed fluid conduit 38 passes defining an annular bleed passage 52 between the piston 34 and the bleed fluid conduit 38. The annular bleed passage 52 is designed to provide bleed fluid from the fluid passageway 28 to the bleed fluid cavity 36. The bleed fluid conduit 38 includes one or more apertures such as 54a located within the bleed fluid cavity 36 and arranged to provide bleed fluid communication between the bleed fluid cavity 36 and the bleed fluid conduit 38.
The valve body 26 of this example also includes a front valve body 56 defining at least part of the fluid passageway 28 and including the fluid inlet 30. The front valve body 56 is operatively coupled to a pilot line such as 16 (see
Importantly the venturi arrangement 40 is operatively coupled to the pilot line 16 and in this embodiment is located within the fluid passageway 28 at the front valve body 56. The bleed conduit 38 connects the bleed fluid cavity 36 within the rear valve body 42 to the venturi arrangement 40 within the front valve body 56. The venturi arrangement 40 is associated with a fluid sampling orifice 62 which samples fluid at or adjacent the fluid inlet 30 for provision to the venturi arrangement 40. With fluid flowing through the pilot line such as 16 in one direction, the venturi arrangement 40 promotes evacuation of bleed fluid from the bleed fluid cavity 36 via the bleed fluid conduit 38 thus reducing pressure within the bleed fluid cavity 36 for opening of the fluid outlet 32 by displacement of the piston 34. With restricted or no fluid flow through the pilot line 16, sampled fluid from the fluid sampling orifice 62 is provided to the bleed fluid cavity 36 at a rear of the piston 34, via the venturi arrangement 40 and the bleed fluid conduit 38, substantially equalising fluid pressure at the rear of the piston 34 relative to the stagnation pressure measured at the sampling orifice 62. During closure of the control valve 12, the fluid pressure is substantially equalised on either side of the piston 34. This equalisation of pressure on closure of the piston 34 together with the difference in the projected area of the piston 34 at the front and the rear creates a force imbalance across the piston 34 to promote closure of the fluid outlet 32 by displacement of the piston 34.
The flow control valve 12 can also be bi-directional and when open operates with fluid flow through the passageway 28 in either direction where fluid flows from the fluid inlet 30 to the fluid outlet 32 or vice versa. Fluid flow through the pilot line in the opposite direction for opening of the valve may be motivated by applying hydraulic fluid pressure to the pilot line via a pump or other device. Alternatively, fluid flow through the pilot line in said one direction for opening of the valve may be motivated by applying a vacuum to the pilot line. In either case, the pilot line is “artificially” energised by an external fluid source which promotes flow through the pilot line in either direction thereby opening the piston. This may have application in draining a tank associated with the flow control valve where flow through the pilot line opens the control valve for reverse fluid flow from the outlet to the inlet of the control valve for draining of the tank. The flow control valve can thus be activated externally via the pilot line without mechanically actuating the control valve itself.
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As described earlier, the chamfer 84 in the piston 34 reduces the area that the seating faces 78 and 82 contact each other thereby:
In another aspect of the invention as best seen in
In this embodiment of this aspect of the invention the flow control valve 12 includes a clasp assembly 90 arranged to clasp the front valve body 56 to the rear valve body 42 for axial securement to one another whilst permitting rotational movement of the front valve body 56 relative to the connector 60. The clasp assembly 90 includes a plurality of flange segments such as 92a arranged to engage the front valve body 56 and a plurality of clasp fasteners such as 94a arranged to engage both the connector 60 and the plurality of flange segments such as 92a for axial securement of the front and rear valve bodies 56 and 42 to one another. In this example the clasp fastener 94a is one of six clasp fasteners 94a to 94f located within respective fastener openings 96a to 96f of the connector 60 and designed to threadingly engage respective of threaded fastener openings 98a to 98f formed in the clasp assembly 90. The pair of flange segments 92a and 92b are substantially identical including an internal annular flange such as 99a configured to engage a corresponding recess 100 formed in the front valve body 56.
As best seen in
Returning to
i) the flow condition and pressure within the pilot line; and
ii) the position of the piston.
Now that several preferred embodiments of the flow control valve and tank overfill protection system have been described it will be apparent to those skilled in the art that they have at least the following advantages:
Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, the piston may depart from its preferred shape provided in cooperation with the venturi arrangement it provides effective closure and opening of the fluid outlet. Similarly, the piston and bleed fluid conduit may be reconfigured without the annular bleed passage of the preferred embodiment provided bleed fluid is effectively supplied to the piston to create the force imbalance required for its displacement and resulting closure of the fluid outlet. The preferred construction of the front valve body and rear valve body in conjunction with the connector may vary where for example locking of the front valve body to the connector provides potentially an infinite number of angular dispositions for the front body for alignment with the associated pilot line. The flow control valve may be directly connected to the tank or indirectly connected in a remote installation to the tank via an intermediate coupling line. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018903182 | Aug 2018 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2019/050911 | 8/28/2019 | WO | 00 |
