Technical Field

[001 ] The invention relates to an over-fill protection apparatus for the filling of a tank. In particular, the invention relates to an over-fill protection apparatus for the top filling of fuel or water tanks.

Background

[002] Tanks such as fuel or water tanks are sometimes required to be filled by rapid filling means. Such rapid filling means may include pumps and hoses that are configured to deliver fluid such as fuel or water at relatively large flow rates to the tank. Such rapid filling may result in tank pressurisation, over-filling and spillage.

[003] Accordingly, various types of flow control systems and apparatuses have been developed. One such flow control apparatus is described in Australian Patent No. 767110. The disclosed flow control apparatus includes a piston arranged to open and close fluid passages to allow fluid to flow from an inlet and through the fluid passages into a tank. The piston is biased by a spring to be closed in the absence of fluid flow. A fluid level sensor in a tank allows fluid to be bled from a downstream side of the piston to enable the piston to move to open the fluid passages. When the fluid sensor detects that the fluid level tank has reached a desired level, the fluid level sensor shuts off fluid bleed and the equalization of the fluid pressure on both sides of the piston enables the spring to move the piston to close the fluid passages, shutting off fluid flow.

[004] A problem with such flow control systems and apparatuses is that even in the shut off state it may be possible to keep adding fluid to the tank that may cause overfilling and spillage.

[005] The invention disclosed herein seeks to overcome one or more of the above identified problems or at least provide a useful alternative. Summary

[006] In accordance with a first broad aspect there is provided, an apparatus for filling a tank with a fluid, the apparatus including a fill assembly and a float assembly. The fill assembly may include a main body with an entry port, a main outlet aperture and a main piston chamber including a main piston, the main piston being biased toward a closed condition and moveable to an open condition in response to fluid flow at the entry port to open the main aperture. The float assembly may include a float assembly extending from the main body so as to be at least partially immersible in fluid within the tank, the float assembly including a float housing with a float, a float valve chamber housing a float piston and a float valve coupled to the float piston and float such that the float valve and the float piston are movable in response to a fluid level in the tank between an open state and a shut-off state in which the main piston is moveable toward the closed condition.

[007] The main piston chamber may include a main chamber inlet aperture to allow fluid communication between the entry port and the main piston chamber, a first outlet aperture openable and closable by the float valve in the respective open and shut-off states and adapted to communicate fluid in the open state between the main piston chamber and a first side of the float piston within the float chamber, and a second outlet aperture adapted to communicate fluid between the main piston chamber and a second side of the float valve in within the float valve chamber in the shut-off state so as to assist to maintain the main piston in the closed condition.

[008] In an aspect, the main piston inlet aperture passes through a head of the main piston.

[009] In another aspect, the head of the main piston includes a centre portion and a tapered portion that extends to a wall of the piston, and wherein the main piston inlet aperture is located at the centre portion.

[0010] In yet another aspect, the main piston chamber houses a biasing element.

[0011] In yet another aspect, the biasing element is a spring. [0012] In yet another aspect, the main body includes an end of travel stop to retain the main piston against the biasing element.

[0013] In yet another aspect, a main separator is provided between main piston chamber and the float piston chamber.

[0014] In yet another aspect, the first outlet aperture passes into the main separator to an upper portion of the main separator chamber defined between the upper side of the piston in the main separator.

[0015] In yet another aspect, the first outlet aperture passes through the main separator to a first portion of the float valve chamber defined between the first side of the float piston and the main separator.

[0016] In yet another aspect, a first float valve chamber aperture is provided between the first portion of the float valve chamber and an external environment.

[0017] In yet another aspect, the second outlet aperture passes to a lower portion the main separator chamber defined between the upper side of the float piston and a float needle jet in an upward position which closes the first outlet aperture.

[0018] In yet another aspect, the second outlet aperture passes to a second portion the float valve chamber defined between the second side of the float piston and a float separator.

[0019] In yet another aspect, the float separator is located between the float valve chamber and the float.

[0020] In yet another aspect, a float valve chamber is provided between the float and an external environment.

[0021] In yet another aspect, a second float valve chamber aperture is provided between the second portion the float valve chamber and an external environment. [0022] In yet another aspect, the float valve is a needle valve adapted to sealingly engage with the first outlet aperture.

[0023] In yet another aspect, the float, float or free moving piston and the float valve are connected for likewise movement.

[0024] In yet another aspect, the float, the float piston and the float valve are connected by a spine.

[0025] In yet another aspect, the fill assembly includes a venting arrangement.

[0026] In yet another aspect, the main body includes an annular fill head and a relatively narrower main housing extending from the fill head in which the main piston chamber is located.

[0027] In yet another aspect, the annular fill head includes a venting arrangement.

[0028] In yet another aspect, the venting arrangement includes an annular vent housing with a plurality of one-way valves adapted to enable venting between the tank and an external environment.

[0029] In yet another aspect, the float housing extends from the main housing, the main housing and the float housing being generally cylindrical and sharing a common axis.

[0030] In accordance with a second broad aspect there is provided, a filling system for the top filling of a tank including an apparatus as described above and herein to fit at or toward a top of the tank.

[0031] In accordance with a third broad aspect there is provided, tank or vehicle with a tank fitted with an apparatus as defined above and herein.

[0032] In accordance with a fourth broad aspect there is provided, an apparatus for filling a tank with a fluid, the apparatus including: a fill assembly including body with an entry port, an outlet aperture and a fill valve arrangement adapted to move between a normally closed condition in the absence of fluid flow and an open condition to enable the filling of the tank via the outlet aperture in response to an applied fluid flow, the fill valve arrangement including a main piston moveable within a main piston chamber; and a float assembly having a float, a float piston, that may be a reverse acting piston, and a float valve, the float being movable between an open state in which the float valve couped to the float is open to allow fluid to flow through a first outlet aperture of the main piston chamber to enable the fill valve arrangement to move to the open condition, and a shut off state in which the float valve couped to the float closes the first outlet aperture to enable the fill valve arrangement to move to the normally closed condition, wherein in the shut-off state a second outlet aperture between the main piston chamber and a float valve chamber in which the float piston is housed directs fluid to urge the float piston and the float valve coupled thereto toward the shut-off state.

[0033] Other aspects and features will become apparent from the description below and accompanying figures.

Brief Description of the Figures

[0034] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which;

[0035] Figure 1 is an isometric view illustrating an over-fill protection apparatus;

[0036] Figure 2 is a side view illustrating the over-fill protection apparatus;

[0037] Figure 3 is a top view illustrating the over-fill protection apparatus;

[0038] Figure 4 is an underside view illustrating the over-fill protection apparatus;

[0039] Figure 5 is an isometric split view illustrating an assembly of the over-fill protection apparatus;

[0040] Figure 6 an exploded isometric view illustrating the over-fill protection apparatus; [0041] Figure 7a is a side sectional view illustrating the over-fill protection apparatus in a filling or open condition;

[0042] Figure 7b is a side sectional view illustrating the over-fill protection apparatus in a shut-off or closed condition;

[0043] Figure 8a is an isometric view illustrating the over-fill protection apparatus fitted to an aperture of a tank;

[0044] Figure 8b is a split isometric view illustrating the over-fill protection apparatus fitted to the aperture of the tank;

[0045] Figure 9 is an example configuration illustrating the over-fill protection apparatus fitted to a large capacity storage tank with venting options; and

[0046] Figure 10 is another example configuration illustrating the over-fill protection apparatus fitted to a tank with venting options.

Detailed Description

[0047] Referring to Figures 1 to 7b, there is shown an apparatus 10 for filling a tank 12 (shown in Figure 9) with a fluid such as, but not limited to, liquid fuel and water. The apparatus 10 generally includes a fill assembly 14 and a float assembly 16 extending from the fill assembly 14. The fill assembly 14 is adapted to allow a fluid to enter the tank 12 in an open or filling condition and the float assembly 16 functions to move and maintain the fill assembly 14 in a closed or shut-off condition when a fluid level in the tank reaches a predetermined level. This prevents over-filling of the tank and associated issues such as tank over pressurisation and spillage.

[0048] The fill assembly 14 includes a main body 18 with an entry port 20, a main outlet apertures 22 and a main or fill valve arrangement 23 that includes a main piston chamber 24 housing a main piston 26. The main piston 26 is biased toward the closed condition by a spring 27 in the absence of fluid flow and is moveable to the open condition in response to fluid flow at the entry port 20 to open the main outlet aperture 12 which allows fluid to flow from the entry port 20 through the main outlet aperture 22 and into the tank 12. In this example, the main outlet aperture 22 is provided as a plurality of annular apertures 28 spaced apart about the main body 18.

[0049] As best shown in Figures 5, 6, 7a and 7b, the main piston 26 includes a first face 29 exposed to the inlet fluid and a second face 31 exposed to the main piston chamber 24. In more detail, the main piston 26 includes a head 30 and an annular wall 32 adapted to sealingly engage with an internal surface 34 of a wall 36 of the main body 18 to provide the main piston chamber 24 between the main piston 26 and a floor 38. The spring 27 is captured within the main piston chamber 24 and bears on the floor 38. The wall 36 of the main body 18 includes an end of travel stop 40, provided in the form of a circlip, to capture and limit travel of the main piston 26. A piston seat 41 is provided between the circlip and the main piston 26. The head 30 includes a central portion 42 and a skirting tapered or sloped portion 43 between the central portion 42 and the annular wall 32. The central portion 42 includes a first main chamber inlet aperture 44, that provides a bleed hole, to allow fluid communication between the entry port 20 and the main piston chamber 24.

[0050] The float assembly 16 extends from the main body 18 so as to be at least partially immersible in fluid within the tank 12 in a fitted condition. It is noted the apparatus 10 may be provided in forms where the fill assembly 14 and the float assembly 16 are a single part or composed of a multiple parts. In this example, preferably, the apparatus 10 is generally presented as a single assembly including both of fill assembly 14 and the float assembly 16 with the float assembly 16 extending from and being supported by the fill assembly 14.

[0051] The float assembly 16 includes a float housing 50 with a float 52, a float valve chamber 54 housing a float piston, also referred to herein as a reverse acting piston, 56 and a float valve 58 coupled to the float piston 56 and float 52 such that the float valve 58 and the float piston 56 are movable in response to a fluid level in the tank between an open state and a closed or shut-off state. The shut-off state provides hydraulic conditions, as further detailed below, to allow the main piston 26 to be moveable toward the closed condition and thereby close the main outlet aperture 22 thereby inhibiting fluid flow. The float assembly 16 includes a spring 53 adapted to bias the float valve 58 into a normally open condition. The float piston 56 rides on a wiper seal 57 and further seals 59 are provided to seal the float valve chamber 54, as shown in Figure 6.

[0052] The float assembly 16 includes a first separator 60 between the float valve chamber 54 and the main piston chamber 24 and a second separator 62 between the float valve chamber 54 and a float chamber 64 in which the float 52 travels. The float chamber 64 includes an end cap 66. And the float chamber 64 and the end cap 66 both include apertures 69 to allow the ingress of fluid to float the float 52.

[0053] The float piston 56 is a double-sided piston or reverse acting piston, having a first side 68 and a second side 70, dividing the float valve chamber 54 into first portion 71 and a second portion 73, respectively. The first separator 60 provides the floor 38 and a first outlet aperture 72 of the main piston chamber 24 allows fluid communication, when the float valve 58 is in an open state, as best shown in Figure 7a, between the main piston chamber 24 and first portion 73 of the float valve chamber 54 and enable fluid pressure to the first side 68. A first valve chamber outlet aperture 80 is provided between the first portion 71 of the float valve chamber 54 and an external environment.

[0054] The float valve 58 includes needle part or closure 75 that is coupled to the float piston 56 and float 52 by a member or spine 74 for likewise movement. The spine 74 is guided by a sleeve 77. The first outlet aperture 72 includes a nozzle 76 adapted to sealingly engage with the needle part 75 to close the first outlet aperture in a shut-off state, as best shown in Figure 7b.

[0055] A second outlet aperture 78 is provided to communicate fluid between the main piston chamber 24 and the second portion 73 to allow fluid pressure to the second side 70 of the float piston 56 in the shut-off state so as to assist to maintain the main piston 26 in the closed condition. In this example, the second outlet aperture 78 is provided through the first separator 60 and includes a conduit 79 arranged to pass around the first portion 71 of the float valve chamber 54 and enters the second portion 73 of the float valve chamber 54. A second valve chamber outlet aperture 82 is provided between the second portion 73 of the float valve chamber 54 and the external environment. The float piston, also referred to as the reverse acting piston, 56 is retrained by a spring to allow it to rest in a downward state when not in use.

[0056] As best shown in Figure 5, the main body 18 further includes an annular fill head 84 and a relatively narrower main housing 86 extending from the fill head 84 in which the main piston chamber 24 is located. The fill head 84 may be threaded to install with the tank 12 and an example of the apparatus 10 fitted to a tank inlet 101 is shown in Figures 8a and 8b. The annular fill head 84 includes a venting arrangement 88 with an annular vent housing 90 with a plurality of one-way valves 92 adapted to enable venting between the tank 12 and an external environment. In this example, the valves 92 are provided in the form of ball valves having balls 91 that seat in seals 99 contained in a ball valve housing 94 within the annular vent housing 90. The float housing 50 extends from and is relatively narrower than the main housing 86 and the main body 18. It is noted that the venting arrangement 88 sits radially proud of the main housing 86 to enable venting past the main housing 86. The venting arrangement 88 includes further seals 95 between the annular vent housing 90 and annular fill head 84. A keeper ring 97 is provided between the annular vent housing 90 and the main housing 86.

[0057] Referring to Figure 9, an example filling system 100 including the apparatus 10 is shown fitted to a tank 12 and positioned so that a safe fill level “L” of the tank 12 activates the float 52 to move the float valve 58 to the shut-off condition and the main piston 26 to the closed condition when the safe fill level is reached. A filling means 102 may be connected to the fill head 84 of the apparatus 10 and an additional vent 104 may be coupled to above annular vent housing 88 to direct any vented gas to the additional vent 104. The filling means 102 may include an elbow 106, a hose 108 and a fill point 110. A further vent or additional apparatus 10 may also be fitted. It is noted that in some examples the apparatus 10 may be fitted with an extension piece to increase its length to accommodate different tank sizes and levels. Figure 10 shows a further example filling system 100 in which like numerals denote like parts.

[0058] Turning now to the function of the apparatus 10, the apparatus 10 generally functions using a differential in pressure on the first and second faces 29, 31 of the main piston 26. During filling, the incoming liquid fluid flow causes the main piston 26 to move down in the body 18 to the point where the spring tension of the spring 27 plus pressure in the main chamber 24 below the main piston 26 is equal to the pressure on the first or top surface 29 of the main piston 26. This pressure equilibrium only operates while the main chamber 24 has a small amount of free-flowing liquid passing in and out at the same time via the first main chamber inlet 44 and the first main chamber outlet 72, respectively.

[0059] When filling is in progress, in the open condition and state, and the liquid level is below the activation level of the float assembly 16, a small amount of liquid bleeds out from the first main chamber outlet 72 at the bottom of the main piston chamber 24 past the open float valve 58 which maintains a decreased chamber pressure and allows the main piston 26 to push down against the spring 27 and remain in the open condition. The restrained open condition may in some examples be approximately 3kPa which is low enough to keep refuelling nozzles from shutting down prematurely.

[0060] During filling, when liquid lifts the float 52 of the float assembly 16, the float valve 58 closes preventing any further liquid from bleeding out of the main piston chamber 24. This causes an increased pressure in the main piston chamber 24 and imbalances the pressure differential across the main piston 26 which allows enough force for the main piston 26 to move up towards a closed or shut off state. There is not sufficient power from this action to cause complete hydraulic lock, but it is sufficient to cause the refuelling nozzle to close. In this example, this increased pressure differential may be about > 18 kPa.

[0061] In order to cause a complete or seek a hydraulic lock, the reverse acting lower float piston 56 is utilised which applies all the flow (pump) pressure used during refuelling to be applied to holding the float valve 58 in the closed state to seal the first outlet aperture 72 of the main piston chamber 24 thus preventing weeping of fluid/pressure in the main piston chamber 24. By introducing the reverse acting hydraulic lock power this provides 99% positive force to close off liquid flow and prevent any further liquid from entering the tank 12. The operator could attempt to open the refuelling nozzle but it is then impossible to add more fuel until the fuel tank level falls below the predetermined fill level. [0062] It is noted that the main piston chamber 24 is dimensioned to cause it to develop a sufficient hydraulic force when the float valve 58 has closed to push the main piston 26 toward the entry port 20. In this position, the main piston 26 is restrained by the end of travel stop 40 at the point where the main outlet apertures 22 have closed preventing any further liquid from entering the tank 12.

[0063] When the tank 12 level lowers, the float valve 58 will drop under gravity as the float 52 drops. There are sufficient exit ports, including the outlet apertures 80, 82, in the float valve chamber 54 to release the stored hydraulic energy after the nozzle is disconnected and the tank fuel level falls. However, the hydraulic stored energy remains while the fuel tank level is "Full". Full Level is typically 40mm from the top of the tank 12 but this may be less depending on flow rates and tank volumes.

[0064] Advantageously, there is provided an over-fill protection apparatus that provides protection against over-pressurising tanks during filling and inhibits overfilling and spillage. The apparatus is a self-contained, self-venting, high speed, safe filling control valve capable of allowing a tank to be filled at rates up to about, for example, 900 Litres per minute without significant pressurization or tank overfilling and with low turbulence and low-pressure losses. The apparatus only requires a single already existing cut-through, usually the existing tank filler neck, for installation on a liquid storage tank to provide a complete filling, venting and overfill protection system. Most advantageously, the apparatus includes a double-sided float piston, also referred to as a reverse acting piston, that in a shut-off state serves to create substantially a hydraulic lock to secure the float valve in the shut-off state and thus the main piston in the closed condition in which the main aperture is closed and fuel flow into the tank is inhibited.

[0065] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. [0066] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates.

[0067] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein.

[0068] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.