GB2582355A

GB2582355A - Overfill restriction device and pressure reset apparatus

Info

Publication number: GB2582355A
Application number: GB1903864.5A
Authority: GB
Inventors: Lloyd Robinson Keith; John Godfrey Christopher
Original assignee: Risbridger Ltd
Current assignee: Risbridger Ltd
Priority date: 2019-03-21
Filing date: 2019-03-21
Publication date: 2020-09-23
Also published as: GB201903864D0

Abstract

An overfill restriction device 50 for a container comprising: a valve body; a valve member 63; a valve actuator 68; a fluid-level detector 64 and a retaining means located on the actuator and/or the valve member to retain the valve in the closed position. Preferably the valve is a poppet valve that is biased closed, the actuator is a cam 68, the retaining means is an ident in the cam and the fluid level detector is a float pivotally coupled to the valve body. Also claimed is a pressure reset apparatus (60, figure 6) having two body portions defining two internal chambers having fluidly connected throughbores. The body portions are biased to be sealed against one another such that the throughbores are isolated from ambient pressure. One of the body portions is movable relative to the other on application of an external force against the sealing bias, preferably manually or with a tool, to open a passage between the body portions and expose the throughbore to ambient pressure. A flow control assembly 10 has a flow control valve 20 and an overfill restriction device and preferably a pressure reset apparatus.

Description

OVERFILL RESTRICTION DEVICE AND PRESSURE RESET APPARATUS

The present invention relates to an overfill restriction device and pressure reset apparatus, particularly, but not exclusively, for substantially restricting overfill of fluid in a container. 5 The critical power industry often uses fuel powered backup generators. One conventional arrangement involves a fuel feed from a bulk storage tank to a day tank, which then feeds fuel directly into a backup generator. Flow control valves are used to control the flow of fuel from the bulk tank into the day tank. Such flow control valves are typically provided with an overflow prevention arrangement which stops fuel from continuing to flow into the day tank once the day tank is full. However, existing valves typically allow a small leak rate. This is undesirable since any leakage or overflow from the day tank is potentially hazardous and damaging to the environment.

According to one aspect of the present invention there is provided a flow control valve, the flow control valve comprising: a valve body defining an internal chamber, the chamber having an inlet, a first outlet, and a second outlet; a piston separating the first and second outlets wherein the piston comprises a piston first piston head provided toward a first end of the piston and comprising at least an orifice therethrough and a second piston head provided toward a second end of the piston; and a closure member accommodated within the valve body for selective closure of the first outlet; wherein the closure member is coupled to the second piston head, and movable with the piston in use, between an open configuration, in which fluid flow through the inlet acts as a dominant force on the first piston head to separate the closure member and the first outlet and allow fluid flow therethrough, and a closed configuration in which fluid flow through the inlet acts as a dominant force on the second piston head and closure member to urge the closure member against the first outlet to substantially prevent fluid flow therethrough; and wherein the transition of the closure member from the open to the closed configuration occurs when flow of fluid through the second outlet is substantially prevented.

Optionally, the closure member and the second piston head are shaped and arranged such that fluid flow from the inlet acting on the first piston head is a dominant force when fluid is flowable through the second outlet. Thus, the flow control valve may be movable into the open configuration by a fluid feed from the inlet Optionally, the transition of the closure member from the open to the closed configurations occurs when there is substantial equalisation of forces across the first piston head. Optionally, substantial prevention of fluid flow through the second outlet causes equalisation of pressure across the first piston head.

Optionally, the inlet, closure member and the piston heads are located, shaped and arranged such that fluid flow from the inlet acting on the closure member is the dominant force when fluid flow is substantially prevented through the second outlet. Thus, fluid pressure acting on the second piston head and closure member becomes the dominant force to close the first outlet, when flow through the second outlet is substantially prevented.

Optionally, the second piston head and the closure member are shaped to present a surface area on which fluid pressure acts. The fluid flow through the inlet can act to retain the closure member in the closed configuration. Thus, there is a positive closure and further fluid pressure from the inlet feed acts on the second piston head to maintain the closure member in the closed configuration.

Optionally, the surface area of the second piston head and closure member is less than the surface area of the first piston head.

Optionally, the second piston head and the closure member are part of a poppet valve.

Optionally, the second outlet is fluidly connected to an overfill restriction device. The overfill restriction device may selectively prevent fluid flow on detecting a predetermined fluid level.

Optionally, the valve further comprises a closure means to act upon the closure member.

Optionally the closure member is biased in the closed configuration. The closure member may be biased in the closed configuration by the closure means. The closure means may comprise a compression spring that acts to bias the closure member against the first outlet. Thus the first outlet of the flow control assembly may be normally biased into a closed position.

Optionally the second outlet extends through a sidewall of the valve body. Alternatively, the second outlet is provided in a stem extending from one side of the piston and through the closure member.

Optionally, the flow control valve is configured to feed fluid into a container. Optionally the flow control valve is adapted to provide a fluid feed for a container such as a tank in the open configuration. Optionally the flow control valve is adapted to substantially restrict fluid flow into the container through the first outlet by sealing the interface between the closure member and the first outlet in the closed configuration.

According to another aspect of the present invention, there is provided an overfill restriction device for a container, the device comprising: a valve body defining an internal chamber; 2 5 a valve member movable within the chamber between an open position and a closed position in which fluid flow through the valve is substantially prevented; a valve actuator cooperable with the valve member to move the valve member into the open and closed positions; a fluid level detector coupled to the valve actuator and movable in response to changing levels of fluid within a container; and a retaining means located on at least one of the valve actuator and/or the valve member to substantially retain the valve actuator and valve member in the closed position.

Optionally, the retaining means comprise cooperable portions located on at least one of the valve member and the valve actuator. Part of at least one of the valve actuator and the valve member may be shaped to retain the valve member and the valve actuator in the closed position.

Optionally, the retaining means is engagable on application of a force from at least one of the valve member and the valve actuator. For example, once fluid within a container reaches a predetermined level, movement of the fluid level detector can apply a force to the valve actuator to retain the valve actuator and the valve member in the closed position.

Alternatively or additionally, a force provided by a fluid pressure applied to the valve member can urge the valve member into the closed position.

Optionally, the valve member comprises a poppet valve. Optionally, the valve member comprises a head portion for sealing against the valve body and a rounded stem extending outwith the internal chamber of the valve body.

Optionally, the valve actuator is a cam. Optionally the cam is shaped to urge the valve member into the open position when the fluid level detector does not detect overfill of fluid in the container.

Optionally the retaining means comprises an indent in the valve actuator cooperable with a portion of the valve member to retain the valve actuator and the valve member is the closed position. Optionally, the retaining means comprises a locking indent in the cam.

Optionally, the locking indent is cooperable with the rounded stem of the valve member extending outwith the chamber.

Optionally, the fluid level detector comprises a float coupled to the valve actuator. Optionally, the fluid level detector is pivotally coupled to the overfill restriction device.

Optionally, the overfill restriction device comprises a biasing means for biasing the valve member into the closed position. The biasing means may comprise a spring Optionally, the container is a tank such as a fuel containing tank and may include a day tank for a generator.

Optionally, the overfill restriction device may be fluidly connected to any compatible fluid feed or valve arrangement.

Optionally, the overfill restriction device may form part of a flow control assembly. One end of the valve body of the overfill restriction device may be coupled to the flow control valve according to another aspect of the invention. The fluid feed for the overfill restriction device may be provided by fluid flow from the second outlet of the flow control valve.

According to another aspect of the present invention, there is provided a pressure reset apparatus for use in conjunction with a valve arrangement, wherein the apparatus comprises: a first body portion defining a first internal chamber and a second body portion defining a second internal chamber, each of the first and second internal chambers having fluidly connected throughbores; wherein the first and second body portions are sealed against one another and biased into a sealing configuration such that the throughbores are isolated from ambient pressure; and wherein at least one of the first and second body portions is movable relative to the other, on application of an external force against the sealing bias, to open a passage between the sealed first and second body portions and expose the throughbore to ambient pressure. 25 Optionally, the first and second body portions are locked in the sealing configuration. Optionally the pressure reset apparatus comprises a locking means to lock the first and second body portions in the sealing configuration. The locking means may be a mechanical locking means. Optionally the locking means comprise a nut, which is threaded on one of the first and second body portions to abut the other second or first body portion. Optionally, releasing the locking means enables relative movement of the first and second body portions.

Optionally, the first and/or second body portions are manually movable. Alternatively, or additionally, the first and/or second body portion is moveable with a tool.

Optionally, the first body portion is slidable relative to the second body portion.

Optionally, the first body portion is at least partially housed within the second body portion.

Optionally, the pressure reset apparatus is connected to an overfill restriction device. The pressure reset apparatus may be connectable to the overfill restriction device described herein. Optionally, the throughbore of the pressure reset apparatus is fluidly coupled to the chamber of the overfill restriction device. The pressure reset apparatus may be operable to bleed pressure from the throughbore to thereby reduce pressure within the chamber of the overfill restriction device and allow the device to reset.

The pressure reset apparatus may form part of a flow control apparatus.

According to a fourth aspect of the invention, there is provided a flow control assembly comprising a flow control valve according to the first aspect of the invention and an overfill restriction device according to a second aspect of the invention.

Optionally, the flow control assembly further comprises a pressure release sensor according to a third aspect of the invention.

The flow control assembly may be a tank feed flow control assembly.

Any aspect, embodiment or feature described herein may be combined with any other aspect, embodiment or feature where appropriate.

Further features and advantages of the first and second aspects of the present invention will become apparent from the claims and the following description.

Embodiments of the present invention will now be described by way of example only, with reference to the following diagrams, in which:-Fig. 1 is an exploded side view of a flow control assembly; Fig. 2 is a side view of the flow control assembly of Figure 1 connected to an overfill restriction device; Fig. 3 is a side view with partial cutaway of the overfill restriction device of Figure 2; Fig. 4 is a sectional view of a float and locking cam in an unlocked position; Fig. 5 is a sectional view of the float and locking cam of Fig. 4 in a locked position; Fig. 6 is a side view of the flow control assembly in an installed configuration; Fig. 7 is a sectional view of the flow control assembly with the flow control valve in a closed position; Fig. 8a is a detailed sectional view of the flow control valve with a fluid feed; Fig. 8b is a detailed sectional view of the overfill restriction device with fluid flowing the rethrou gh; Fig. 9 is a detailed sectional view of the flow control valve in an open position; Fig. 10 is a detailed sectional view of the float and locking cam in a locked position; Fig. 11 is a sectional view of the flow control assembly in the locked position and diagrammatically illustrating pressure causing the flow control valve to close; Fig. 12 is a sectional view of the flow control assembly with a nut of the pressure reset apparatus in an unscrewed position; Fig. 13 is a sectional view of the flow control assembly with the nut of the pressure reset apparatus and a first body portion depressed to release the pressure within the assembly; Fig. 14 is a side view of the flow control assembly in a reset configuration; and Fig. 15 is a sectional schematic view of an alternative embodiment of a flow control assembly.

A flow control assembly is shown generally at 10 in Figure 2. The flow control assembly 10 comprises a flow control valve 20 and an overfill restriction device 50 connected via a connecting hose 11.

An exploded view of the flow control valve 20 is shown in Figure 1. A linkage body 13 is provided at an upper end of the flow control valve 20. An upper outlet and a hose adaptor 12 extends from the linkage body 13 perpendicular to a main axis of the flow control valve 20. The linkage body 12 is sealed against an end cap 15 by an o-ring seal 14. An interior of the end cap 15 accommodates a spiral retaining ring 17 for retaining a compression spring 19 and a seal 18. A first hollow body portion 23 seals against the end cap 15 via an o-ring seal 16 and creates a first chamber 38 which houses the compression spring 19. A lower end of the compression spring 19 acts against a first piston head 22 containing an orifice 35 shown in Figures 8a and 9. A nut 21 attaches the piston head 22 to a valve stem 33 that is housed within a second hollow body portion 24. The second hollow body portion 24 seals against the first hollow body portion 23 via an o-ring seal 27 and creates a second chamber 37. The valve stem 33 has a second piston head in the form of a flared poppet 34, a valve seal 28 and a poppet cap 29 at the lower end. The second body portion 24 has an inlet 25 extending through a sidewall and a lower outlet 26 at the lower end of the flow control valve 20. The lower outlet 26 is sealed at 28 by the poppet 34 in the lowermost position. At rest, in the absence of other applied forces, the poppet valve 34 is normally held in the closed position and is urged closed by the force of the compression spring 19.

The connecting hose 11 provides a conduit for fluid communication between the upper outlet and hose adaptor 12 of the flow control valve 20 and the overfill restriction device via a pressure reset apparatus 60 shown in Figures 3, 6 and 8b.

The pressure reset apparatus 60 connects to the hose 11 via a connector 51. The pressure reset apparatus 60 comprises a first internal hollow body portion 78 and a second outer hollow body portion 79 having a common throughbore 73. The body portions 78, 79 are mechanically locked together by a nut 75 and sealed against one another via a seal 76 to substantially isolate the throughbore 73 from ambient pressure. The pressure reset apparatus 60 is joined to the overfill restriction device 50 via a compression sleeve 52 and a compression nut 53. A tube 54 connects the upper components of the pressure reset apparatus 60 to an end cap 55 of the overfill restriction device 50. The end cap 55 is sealed against a hollow valve body 58 by an o-ring seal 56 as shown in more detail in Figures 4 and 5. The valve body 58 defines a chamber 71 that houses a spring 57, and a valve member in the form of a poppet 63 having a sealing head portion with a poppet seal 59 and a rounded stem that extends outwith the chamber 71. A lower end of the valve body 58 accommodates a valve actuator in the form of a cam 68. The cam 68 is pivotable around a pivot pin 61 to move the poppet 63 within the valve body 58 between open and closed positions. The cam 68 is attached to a rod 67. The end of the rod 67 is secured against a fluid level float 64 by a washer 65 and a clip 66. The cam 68 has a locking indent 69, such that when the cam 68 pivots on the rod 67 as the float 64 rises, the poppet 63 seats in the indent 69 and the cam 68 retains or locks the poppet 63 in the closed position.

In the presently described embodiment, prior to use, the flow control assembly 10 is installed as part of a fuel delivery system to supply fuel to a day tank from a bulk storage tank (not shown). The inlet 25 of the flow control valve 20 is connected to a fuel feed from the bulk storage tank. Figures 6 and 7 show the flow control assembly 10 in an installed configuration within a day tank 30 with the outer body portion 79 of the pressure reset apparatus 60 aligned with a lower end of the flow control valve 20 on an illustrative install line 32. The fluid level float 64 of the overfill restriction device 50 extends downwardly into the fuel tank 30. The flow control assembly 10 is provided to allow the day tank to be filled with fuel from the bulk tank via the outlet 26 of the flow control valve 20 at a relatively high flow rate, while protecting against overfill of the day tank 30 by means of the overfill restriction device 50.

Figure 7 is a sectional view showing the flow control assembly 10 prior to fuel being pumped from the bulk storage tank. The flared poppet 34 of the flow control valve is normally closed since the compression spring 19 acts on the piston 22 attached to the valve stem 33 to urge the valve seal 28 against the valve seat and thereby seal the lower outlet 26. There is a fluid communication path between the flow control valve 20 and the overfill restriction device 50 via the orifice 35 in the piston 22 and the connecting hose 11. The overfill restriction device 50 permits a choked or relatively low flow rate bleed path into the fuel tank 30. Prior to filling the day tank 30, the fluid level float 64 extends downwardly under gravity resulting in the cam 68 adopting an upright position and urging the poppet valve 63 and the valve seal 72 away from the valve seat. Therefore the valve 58 of the overfill restriction device 50 is set in an open position.

When an operator requires the day tank 30 to be filled, fuel is pumped from the bulk storage tank (not shown) through the inlet 25 of the flow control valve 20 as shown in Figure 8a. The direction and flow of pumped fuel is illustrated by arrows 36. Fluid enters the lower chamber 37 and acts on both the flared poppet 34 of the second piston head and the first piston head 22. A flow of fluid bleeds through the orifice 35 and hence passes though the piston head 22 and into the upper chamber 38. Fluid within the upper chamber 38 flows through the hose adaptor 12 and the connecting hose 11 into the overfill restriction device 50 shown in Figure 8b. Fluid flows within the throughbore 73 of the pressure reset apparatus 60 as shown by arrows 36 and bypasses the valve seal 72 of the poppet 63 that is held off the valve seat by the cam 68. Fluid can thereby exit the overfill restriction device 50 at the outlet 77 as shown in Figure 8b.

Continued fuel feed through the inlet 25 of the flow control valve 20 causes opening of the flow control valve 20. Since there is a fluid outlet 77 downstream of the upper chamber 38 and a small orifice 35 through which fluid can pass across the first piston head 22, a pressure differential is established across the first piston head 22. Once the pressure differential across the first piston head 22 overcomes the force of the compression spring 19, the first piston head 22 is urged upwardly within the chamber 38, thereby moving the attached stem 33 and poppet 34 of the second piston head off the valve seat in order to open the lower outlet 26 of the flow control valve 20. Arrows 36 illustrate the route of fluid flow into the day tank 30 at a high rate (relative to the fluid flowing through the overfill restriction device 50) as the flow control valve 20 is opened in Figure 9.

Fuel flows into the day tank 30 to provide a fuel feed for a generator (not shown). It is typically desirable to fill the day tank, however the tank 30 should not be overfilled as this is potentially hazardous and can result in environmental damage. As the upper level 31 of fuel rises within the tank 30, the fluid level float 64 also rises because it has a positive buoyancy calculated relative to the fuel. Movement of the float 64 is translated to the rod 67 to which the float 64 is attached, and the rod 67 pivots around the pivot pin 61. The cam 68 is attached to one end of the rod 67 and therefore also rotates. Continued filling of the tank 30 causes the float 64 to pivot through around 90 degrees as shown in Figure 10. In this position, the indent 69 of the cam 68 is positioned underneath the poppet 63. The rounded end of the poppet 63 stem drops into the indent 69 such that the head of the poppet 63 seals at 72 against the valve seat under the urging of the spring 57. The lower rounded end of the poppet 63 seats in the indent 69 of the cam 68 to thereby retain or lock the poppet 63 of the overfill restriction device 50 in the closed position. Pressure within the throughbore 63 increases once the poppet 63 is in the closed position and this pressure locks the poppet 63 in the indent 69 of the cam 68 through the continued force applied to the head of the poppet 63.

When the day tank 30 is full, the closure of the poppet valve 63 causes pressure to increase within the throughbore 73 of the overfill restriction device 50. Once the outlet 77 is closed fluid begins to back up within the throughbore 73, the connecting hose 11 and the upper chamber 38. The fluid is illustratively depicted by arrow 80 in Figure 11, which illustrates the pressure increase within the flow control assembly 10. The pressure across the first piston head 22 equalises and there is therefore no longer any pressure differential in existence to maintain the valve poppet 34 of the flow control valve 20 in the open position. Therefore the dominant force becomes the force of fluid flow applied by the inlet 25 fluid feed against the flared poppet 34 and the compression spring 19, both of which urge the valve poppet 34 into a closed position to seal 28 against the valve seat and close the lower outlet 26. Since the overfill restriction device 50 is locked in position by the indent 69 in the cam 68, the flow control assembly 10 remains in this closed configuration with no available outlet 26, 77 or fuel path into the tank 30.

Any continued fuel feed from the bulk storage tank maintains a positive closing pressure on the poppet 34 face against the lower outlet 26 of the flow control valve 20. This ensures a positive closure of the flow control valve 20 and substantially prevents leakage of fuel into the day tank 30. In addition, the overfill restriction device 50 is locked in a closed position by the positive pressure 80 acting to urge the poppet 63 into the retaining indent 69 in the cam 68. Therefore, risk of overfill of fuel in the tank 30 is significantly reduced.

In order to release the locked overfill restriction device 50, the fluid level 31 within the tank 30 needs to drop so that there is sufficient space for the fluid level float 64 and attached cam 68 to pivot downwardly into the ullage of the day tank. According to the present embodiment, the overfill restriction device 50 must also be manually unlocked by bleeding the pressure within the throughbore 73. The unlocking process of the overfill restriction device 50 is shown in Figures 12 and 13. An operator (not shown) manually unscrews the nut 75 at the upper end of the pressure reset apparatus 60. Unscrewing the nut 75 creates a gap between the upper internal body portion 78 of the pressure reset apparatus 60 and the lower external body portion 79 as shown in Figure 12. The nut 75 is then manually depressed against the force of a spring to slide the upper internal body portion 78 of the pressure reset apparatus 60 within the lower external body portion 79. This results in a gap forming between the two body portions 78, 79 and the separation of seals 76 to create an outlet 82 through which pressure 81 can be vented, as shown in Figure 13. Release of the pressure 81 from the throughbore 73 reduces the pressure acting on the head of the poppet 63 urging the poppet 63 into the indent 69 of the cam 68. Gravity acting upon the float 64 and rod 67 becomes the dominant force and the float 64 pivots around the pin 61 to adopt a near vertical position. The attached cam 68 also pivots such that the rotating cam 68 acts on the poppet 63 to push the poppet 63 upwardly within the valve chamber 71 and away from the valve seat. Thus, the outlet 77 of the overfill restriction device 50 in opened again. In this way the flow control assembly 10 is unlocked and reset for future use as shown in Figure 14.

With reference to Figure 15, a further embodiment of the present invention will now be described. In order to minimise repetition, similar features of the apparatus described subsequently are numbered with a common two-digit reference numeral and are differentiated by a third digit, '1', placed before the two common digits. Such features are structured similarly, operate similarly, and/or have similar functions as previously described unless otherwise indicated.

The embodiment shown in Figure 15 has features in common with the previous embodiment, such as the piston 122, orifice 135, spring 119 and poppet 134. However, the flow control valve 120 works in conjunction with an alternative overfill restriction device 150. The valve stem 133 of the flow control valve 120 has a throughbore to allow fluid to flow to a bleed outlet 177 as depicted by the arrows 136. The float 164 is moveable in a vertical plane to close the bleed outlet 177 once the upper level of fluid 31 within the tank rises. This closure of the outlet 177 restricts the flow of fluid and pressure therefore builds in the upper chamber 138. Pressure equalises across the piston 122 such that the spring force 119 becomes the dominant force, which thereby results in positive closure of the poppet valve 134.

Although particular embodiments of the invention have been disclosed herein in detail, this is by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the statements of invention and/or appended claims. Relative terms such as "upper" and "lower" are not intended to be limiting with respect to the scope of the invention.

It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the scope of the invention as defined by the statements of invention and/or claims. Examples of these include the following:-since the apparatus previously described may, in certain instances, be primarily utilised as a backup / failsafe to an electronic or other primary level control system, the valve of the poppet 63 and valve seal 72 of the overfill restriction device 50 may never / rarely be actuated to form a seal. Therefore, the flow control valve 20 and / or overfill restriction device 50 may also be provided with a testing arrangement which allows the operation of the overfill restriction device 50 to be tested. This may be provided so as to allow the operation to be tested during a filling cycle. This testing arrangement may comprise a manually operable spring-loaded poppet valve mounted to the flow control valve 20 and / or overfill restriction device 50. Depressing the manually operable spring-loaded poppet valve will act to manually shut off the low / bleed flow of fluid to the overfill restriction device 20 (regardless of the level of fluid, and hence the position of the float sensor 64, in the tank 30).

This in turn will cause the overfill restriction device 50 (and hence the flow control valve 20) to operate in the aforementioned desired fashion (assuming it is fully operational). In this way, the integrity of the system's ability to shut off fluid in an overfill scenario can be tested without an overfill scenario needing to occur. Rather than being manually operable the aforementioned spring-loaded poppet valve may also be operable in some other way -including electronically or automatically. 'container' should be considered to include any type of repository for containing a liquid, such as tanks, drums, fuel cells, bladders or other suitable storage devices; and fluid' should be taken to include any flowable fluid including but not limited to fuels (diesel and petrol), water, water-based solutions and the like.

Claims

CLAIMS1. An overfill restriction device for a container, the device comprising: a valve body defining an internal chamber; a valve member movable within the chamber between an open position and a closed position in which fluid flow through the valve is substantially prevented; a valve actuator cooperable with the valve member to move the valve member into the open and closed positions; a fluid level detector coupled to the valve actuator and movable in response to changing levels of fluid within a container; and a retaining means located on at least one of the valve actuator and/or the valve member to substantially retain the valve actuator and valve member in the closed position.
2. An overfill restriction device according to claim 1, wherein the retaining means comprise cooperable retaining portions located on at least one of the valve member and the valve actuator.
3. An overfill restriction device according to claim 1 or claim 2, wherein part of at least one of the valve actuator and the valve member is shaped to retain the valve member and the valve actuator in the closed position.
4. An overfill restriction device according to any preceding claim, wherein the retaining means is engagable on application of a force from at least one of the valve member and the valve actuator.
5. An overfill restriction device according to any preceding claim, wherein the valve member comprises a poppet valve having a head portion for sealing against the valve body and a rounded stem extending outwith the chamber of the valve body.
6. An overfill restriction device according to any preceding claim, wherein, the valve actuator comprises a cam shaped to urge the valve member into the open position when the fluid level detector does not detect overfill of fluid in the container.
7. An overfill restriction device according to any preceding claim, wherein the retaining means comprises an indent in the valve actuator cooperable with a portion of the valve member to retain the valve actuator and the valve member is the closed position.
8. An overfill restriction device according to claims 5, 6 and 7, wherein the retaining means comprises a locking indent in the cam, and wherein the locking indent is cooperable with the rounded stem of the valve member extending outwith the chamber.
9. An overfill restriction device according to any preceding claim, wherein the fluid level detector comprises a float coupled to the valve actuator.
10. An overfill restriction device according to any preceding claim, wherein the fluid level detector is pivotally coupled to the valve body.
11. An overfill restriction device according to any preceding claim, wherein, the overfill restriction device comprises a biasing means for biasing the valve member into the closed position.
12. A pressure reset apparatus for use with a valve arrangement, wherein the apparatus comprises: a first body portion defining a first internal chamber and a second body portion defining a second internal chamber, each of the first and second internal chambers having fluidly connected throughbores; wherein the First and second body portions are sealed against one another and biased into a sealing configuration such that the throughbores are isolated from ambient pressure; and wherein at least one of the first and second body portions is movable relative to the other, on application of an external force against the sealing bias, to open a passage between the sealed first and second body portions and expose the throughbore to ambient pressure.
13. A pressure reset apparatus according to claim 12, wherein the pressure reset apparatus comprises a locking means to lock the first and second body portions in the sealing configuration.
14. A pressure reset apparatus according to claim 13, wherein the locking means are a mechanical locking means comprising a nut, which is threaded on one of the first and second body portions to abut the other second or first body portion.
15. A pressure reset apparatus according to claim 13 or claim 14, wherein release of the mechanical locking means enables relative movement of the first and second body portions.
16. A pressure reset apparatus according to any one of claims 12 to 15, wherein the first and/or second body portions are movable manually and/or with a tool.
17. A pressure reset apparatus according to any one of claims 12 to 16, wherein the first body portion is at least partially housed within the second body portion and wherein the first body portion is slidable relative to the second body portion.
18. A pressure reset apparatus according to any one of claims 12 to 17, wherein the pressure reset apparatus is connectable to an overfill restriction device according to any one of claims 1 to 11.
19. A pressure reset apparatus according to any one of claims 12 to 18, wherein the throughbore of the pressure reset apparatus is fluidly coupled to the chamber of the overfill restriction device according to and one of claims 1 to 11.
20. A pressure reset apparatus according to any one of claims 12 to 19, wherein the pressure reset apparatus is operable to bleed pressure from the throughbore to thereby reduce pressure within the chamber of the overfill restriction device according to any one of claims 1 to 11.
21. A flow control assembly comprising a flow control valve and an overfill restriction device according to any one of claims 1 to 11, wherein one end of the valve body of the overfill restriction device is coupled to the flow control valve.
22. A flow control assembly according to claim 21, further comprising a pressure reset apparatus according to any one of claims 12 to 17 located between the flow control valve and the overfill restriction device.