AU2017287793A1

AU2017287793A1 - A vapour recovery system and method of operation

Info

Publication number: AU2017287793A1
Application number: AU2017287793A
Authority: AU
Inventors: Peter Andrew Scragg; Ronald WIN
Original assignee: Gallagher Group Ltd
Current assignee: Gallagher Group Ltd
Priority date: 2016-07-01
Filing date: 2017-06-30
Publication date: 2019-02-21
Also published as: WO2018004361A1; MX2019000015A

Abstract

A vapour recovery system is disclosed, configured to be retrofitted to a liquid fuel dispensing facility having at least one liquid fuel dispensing unit and at least one dispenser liquid fuel volume sensing device for measuring the volume of fuel dispensed. At least one dispensing unit nozzle and hose is provided, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit. A fuel vapour delivery conduit connects to the fuel vapour recovery conduit for delivery of fuel vapour to a storage tank. A vapour recovery pump unit is located remotely from the dispensing unit to provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank. A vapour recovery liquid fuel volume sensing device is galvanically isolated from the dispenser liquid fuel volume sensing device, and configured to output a signal indicative of the volume of liquid fuel being dispensed.

Description

A VAPOUR RECOVERY SYSTEM AND METHOD OF OPERATION

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the specification filed in relation to New Zealand Patent Application No. 721822, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a vapour recovery system and method of operation - more particularly vapour recovery from liquid fuel dispensers of a refuelling station.

BACKGROUND ART

Liquid fuel dispensers (commonly referred to as fuel pumps) are well known for the dispensing of liquid fuel into motor vehicle fuel tanks at refuelling stations. When the liquid fuel is dispensed into the fuel tank, fuel vapours are displaced and forced out of the tank, into the atmosphere. This is both wasteful, and widely acknowledged as being damaging to the environment.

Many countries have legislated requirements that the vapour is recovered while refuelling is taking place. This is typically achieved either by extracting the vapour back from the fuel tank while refilling, or by an onboard vapour storage means where the vapour is then later released to be used by the combustion engine of the vehicle. This second method is considered to have disadvantages with regard to the placing of the burden of recovering the vapour on each individual vehicle, and being uneconomic in comparison to having suitable vapour recovery equipment at the refuelling station.

Consequently, many new fuel dispensing systems incorporate vapour recovery systems which extract fuel vapour from the fuel tank simultaneously with the liquid fuel being dispensed into the fuel tank. However, there remain a large number of existing fuel dispensing systems that do not incorporate vapour recovery systems, or have vapour recovery systems that drift out of calibration. Replacing such infrastructure globally is an enormous undertaking, and for many countries and businesses is economically infeasible.

In some countries (for example, through numerous members of the EU) vapour recovery systems have been retrofitted into existing fuel dispensing systems to limit the disruption and the expense of entirely replacing existing infrastructure. Such retrofitting has, to date, required the integration of additional

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PCT/NZ2017/050089 equipment such as vacuum pumps, motors, and vapour flow measurement instruments into the cabinet of each fuel dispenser - as well as fitting replacement hoses and nozzles incorporating both a dispensing fluid flow conduit and a vapour recovery flow conduit. Additional control instrumentation has also been incorporated into the dispenser to match the volume of vapour extracted with the volume of liquid fuel dispensed.

However, existing retrofitting techniques and systems can have numerous problems. For example, there are often space restrictions in pre-existing fuel dispenser cabinets that make incorporation of conventional vapour recovery equipment difficult.

Another problem is that there are stringent safety requirements governing fuel dispensing equipment. Modification of, or integration with, existing electronics and control equipment usually requires retesting and recertification of the refuelling system, at prohibitive cost.

Further, the fuel flow metering equipment, fuel pumps, motors, and fuel ducts are typically located in what is known as the 'hazardous area' which for petrol dispensers may be at a level lower than 1.2 metres above ground level on the forecourt, where fuel vapours can accumulate and are at risk of ignition. Typically, a signal cable is routed from the fuel flow metering equipment in the hazardous area up to the electronics and control equipment, which is usually located in a 'non-hazardous area' (for example, higher than 1.2 metres above ground level and incorporating a vapour barrier). This presents challenges with regard to achieving a low power expenditure and the need to reduce the likelihood of ignition within the hazardous area.

It is also difficult to integrate a vapour recovery system into a fuel dispensing system of an unknown or different manufacturer, for which it can be difficult (if not impossible) to obtain technical specifications to facilitate this integration.

It is an object of this invention to overcome at least one of the aforementioned problems of retrofitting a vapour recovery system to existing fuel dispensing systems, or at least to provide the public a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

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Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of including, but not limited to.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

SUMMARY

According to an aspect of the present disclosure there is provided a vapour recovery system configured to be retrofitted to a liquid fuel dispensing facility comprising at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source and at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit. The vapour recovery system includes at least one dispensing unit nozzle and hose, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit. The vapour recovery system further includes at least one fuel vapour delivery conduit configured to be connected to the fuel vapour recovery conduit for delivery of fuel vapour to a storage tank. The vapour recovery system further includes at least one vapour recovery pump unit configured to provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank. The vapour recovery system further includes at least one vapour volumetric flow control device configured to be controllable to adjust the volumetric flow rate through the fuel vapour delivery conduit. The vapour recovery system further includes at least one vapour recovery liquid fuel volume sensing device galvanically isolated from the dispenser liquid fuel volume sensing device, and configured to output a signal indicative of the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit. The vapour recovery system further includes at least one vapour volumetric flow controller, wherein the vapour volumetric flow controller is configured to receive the signal from the vapour recovery liquid fuel volume sensing device and control the vapour volumetric flow control device in accordance with the volume of liquid fuel being dispensed.

According to an aspect of the present disclosure there is provided a method of operating a liquid fuel dispensing facility retrofitted with a vapour recovery system substantially as herein described. The method includes receiving the signal indicative of the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit. The method further includes determining a target volumetric flow rate through the fuel vapour delivery conduit based on the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit. The method further includes controlling the vapour volumetric flow control device according to the target volumetric flow rate.

According to an aspect of the present disclosure there is provided a vapour recovery system configured

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PCT/NZ2017/050089 to be retrofitted to a liquid fuel dispensing facility comprising at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source and at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit. The vapour recovery system includes at least one dispensing unit nozzle and hose, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit. The vapour recovery system further includes at least one fuel vapour delivery conduit configured to be connected to the fuel vapour recovery conduit for delivery of fuel vapour to a storage tank. The vapour recovery system further includes at least one vapour recovery pump unit configured to be located remotely from the at least one liquid fuel dispensing unit, to provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank. The vapour recovery system further includes at least one vapour recovery liquid fuel volume sensing device galvanically isolated from the dispenser liquid fuel volume sensing device, and configured to output a signal indicative of the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit.

According to an aspect of the present disclosure there is provided a vapour recovery system configured to be retrofitted to a liquid fuel dispensing facility comprising at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source and at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit. The vapour recovery system includes at least one dispensing unit nozzle and hose, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit. The vapour recovery system further includes at least one fuel vapour delivery conduit configured to be connected to the fuel vapour recovery conduit for delivery of fuel vapour to a storage tank. The vapour recovery system further includes at least one vapour recovery pump unit configured to be located remotely from the at least one liquid fuel dispensing unit, to provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank.

According to an aspect of the present disclosure there is provided a liquid fuel dispensing facility. The liquid fuel dispensing facility includes at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source. The liquid fuel dispensing facility further includes at least one vapour recovery system substantially as herein described.

According to an aspect of the present disclosure there is provided a kit set for retrofitting a liquid fuel dispensing facility to provide vapour recovery functionality, the kitset including the vapour recovery system substantially as herein described.

A liquid fuel dispensing facility typically includes a plurality of liquid fuel dispensing units. Each liquid dispensing unit includes at least one delivery hose terminating in a fuel nozzle, fluidly connected to a

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PCT/NZ2017/050089 source of fuel. In an exemplary embodiment, the storage tank configured to be connected to the fuel vapour delivery conduit may be that of a fuel source - for example an underground storage tank.

In an exemplary embodiment, each dispensing unit may be capable of delivering one or multiple products - for example, diesel, LPG, petrol, or grades thereof - referred to in the fuel dispensing industry as a Multiple Product Dispenser (MPD). In an exemplary embodiment in which the fuel dispensing facility dispenses multiple octane ratings of a fuel, the storage tank configured to be connected to the fuel vapour delivery conduit may be that of a fuel source of the lowest octane rating fuel.

Reference to a set of hoses of a dispensing unit should be understood to mean a grouping of at least two hoses and their associated nozzles, each configured to deliver a different product. Dispensing units often include two sets of hoses - one on each side - each set capable of dispensing liquid fuel independently from the other and therefore requiring independent vapour recovery. In an exemplary embodiment, each dispensing unit may be provided with a fuel vapour delivery conduit for each set of hoses of the same fuel type. In an exemplary embodiment a fuel vapour manifold may connect the fuel vapour recovery conduits of a set to its associated fuel vapour delivery conduit.

Reference to a hazardous area as used herein should be understood to mean an area surrounding a dispensing unit in which there is an elevated risk of ignition of fuel vapour. For petrol dispensers in which the petrol and/or petrol vapour is under pressure, the hazardous area may extend from ground level to 1.2 m, although it should be appreciated that this may be dependent on national legislation of the country in which the vapour recovery system is to be installed. Similarly, a non-hazardous area of the dispensing unit may be more than 1.2 m above ground level, and the dispensing unit may include a vapour barrier to restrict the flow of vapour from the hazardous area to the non-hazardous area. It should be appreciated that the non-hazardous area may still be classified as a lower grade hazard - i.e. is intended to be an indication of a relatively lower risk of ignition. The cabinets of dispenser units are typically configured to include upper and lower portions, the upper portion raising a number of electronic components above the hazardous area in order to reduce the associated risk.

In an exemplary embodiment, each dispensing unit may include a dispenser controller configured to control and monitor dispensing of the liquid fuel from that dispenser. These dispenser controllers are well known in the fuel dispensing industry for controlling the volume and rate of fuel dispensed from the dispensing unit. Such controllers are typically located within the upper portion of the cabinet of the dispensing unit. In an exemplary embodiment the vapour recovery system may be galvanically isolated from the dispenser controller.

In an exemplary embodiment the vapour recovery system may be powered independently of the

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PCT/NZ2017/050089 dispensing unit. Known dispensing units may include at least one liquid fuel pump configured to dispense liquid fuel through the liquid fuel dispensing conduit. In one known configuration, the dispenser liquid fuel volume sensing device may be integrated with the liquid fuel pump - for example a 4 piston meter connected to an electronic pulser - although it should be appreciated that other sensing devices are known. The output signal of the dispenser liquid fuel volume sensing device is typically transmitted to the dispenser controller by way of a cable, routed between the lower and upper portions of the cabinet of the dispensing unit.

Reference to the vapour recovery system (or components thereof) being galvanically isolated from the dispensing unit (or components thereof) in exemplary embodiment should be understood to mean the isolating of functional sections of the associated electrical systems to prevent current flow between them - i.e. no direct conduction path is permitted. In such embodiments, the galvanic isolation may reduce the likelihood of disruption to the dispensing unit function and control which might otherwise require the existing electronics to be recalibrated or recertified. It may also reduce the likelihood of introducing an ignition source within the hazardous (or non-hazardous) areas.

In an exemplary embodiment the at least one vapour recovery pump unit may be configured to be located remotely from the at least one liquid fuel dispensing unit, and provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank. In exemplary embodiments, components of the vapour recovery pump unit described herein may be separated - for example housed in separate housings, or compartments of housings.

In an exemplary embodiment the vapour recovery pump unit may be configured to service a plurality of dispensing units - i.e. connected to a plurality of the fuel vapour delivery conduits. In an exemplary embodiment the vapour recovery pump unit may be installed at a distance less than 50 metres from each of the dispensing units it is configured to service.

In an exemplary embodiment the vapour recovery pump unit may include at least one pump. In an exemplary embodiment the vapour recovery pump unit may include at least two pumps - more particularly two pumps connected in series.

In an exemplary embodiment the vapour recovery system may include a vacuum controller configured to control operation of the vapour recovery pump unit. In an exemplary embodiment the vacuum controller may be configured to maintain a substantially constant vacuum at the vapour delivery conduits during operation.

In an exemplary embodiment the vapour recovery system may include at least one vapour volumetric flow control device configured to be controllable to adjust the volumetric flow rate through the fuel vapour delivery conduit. The vapour volumetric flow control device may be any suitable device known

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PCT/NZ2017/050089 in the art for the control of the volumetric flow of a fluid - particularly vapourised fuel, or an air-fuel mixture. For example, the vapour volumetric flow control device may be a controllable valve such as a proportional valve.

In an exemplary embodiment the at least one vapour volumetric flow control device may include a valve configured to maintain a fixed orifice to which the vacuum is applied to provide vapour recovery through the fuel vapour delivery conduit - i.e. is not variable in response to the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit. In an exemplary embodiment, such a valve may be manually adjustable.

In an exemplary embodiment, the at least one vapour recovery pump unit may include the at least one vapour volumetric flow control device. It is envisaged that a dedicated vapour volumetric flow control device may be provided for each dispensing hose, or set of hoses, of a dispensing unit which the pump unit is intended to service.

In an exemplary embodiment the vapour recovery system may include at least one vapour volumetric flow controller, wherein the vapour volumetric flow controller is configured to receive the signal from the vapour recovery liquid fuel volume sensing device and control the vapour volumetric flow control device in accordance with the volume of liquid fuel being dispensed.

In an exemplary embodiment the at least one vapour recovery pump unit may include the at least one vapour volumetric flow controller. In an exemplary embodiment the vacuum controller and the at least one vapour volumetric flow controller may be integrated, although it should be appreciated that this is not intended to be limiting.

In an exemplary embodiment determining a target volumetric flow rate through the fuel vapour delivery conduit includes determining the volumetric rate at which vapour is displaced from a fuel tank into which the liquid fuel is dispensed. In an exemplary embodiment the target volumetric flow rate through the fuel vapour delivery conduit may be the volumetric flow rate of liquid fuel being dispensed through the liquid fuel dispensing conduit.

As liquid fuel is dispensed into the fuel tank of a consumer's vehicle, the equivalent volume of vapour is displaced and requires recovery - or be lost to the atmosphere. Further, as liquid fuel is extracted from the storage tank, an equivalent volume of gas is required to be introduced to balance pressure within the storage tank. If not provided by the vapour recovery system, air from the atmosphere will be utilised. The introduction of air from the atmosphere into the storage tank results in a greater proportion of the stored liquid fuel vapourising in comparison with the same volume of an air-fuel mixture returned by the vapour recovery system. In addition to losses of the liquid fuel available for delivery, the volume of the vapourised air-fuel mixture resulting from the introduction of air from the

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PCT/NZ2017/050089 atmosphere is greater than that initially utilised. This may require venting to the atmosphere to rebalance pressure, in turn resulting in fuel losses and reducing the environmental benefits to vapour recovery.

In an exemplary embodiment the vapour recovery system may include at least one vapour flow rate sensing device configured to output a signal indicative of the vapour volumetric flow rate through each fuel vapour delivery conduit, as known in the art. In an exemplary embodiment the at least one vapour flow rate sensing device may be provided at the vapour recovery pump unit.

In an exemplary embodiment the vapour recovery system may use the signal from the at least one vapour flow rate sensing device as part of a closed loop feedback control system for control of the vapour volumetric flow control device.

In an exemplary embodiment, the vapour recovery system may include a fuel dispenser activation sensing device configured to output a signal indicative of the dispensing unit being activated to dispense liquid fuel. It is envisaged that in an exemplary embodiment the vacuum pump unit may be placed in a rest state when there is no demand for vapour recovery, in which a reduced vacuum level may be maintained (for example, 85% of the nominal operational vacuum level). On determining that the dispensing unit has been activated to dispense liquid fuel, the vacuum controller may activate the vacuum pump in order to ensure that the operational vacuum is present when the fuel is dispensed. If initiation of vapour recovery is delayed until after liquid fuel is dispensed, some vapour from the vehicle's fuel tank may be lost to atmosphere, the storage tank may use air from atmosphere for pressure balancing - as described above.

In an exemplary embodiment the fuel dispenser activation sensing device may be, for example a dedicated nozzle lift sensor or a liquid fuel flow sensor. In an exemplary embodiment the fuel dispenser activation sensing device may be galvanically isolated from the liquid fuel dispensing system. For example, the sensing device may be configured to sense the delivery of a control signal through a power control cable joining one or more of: the dispenser controller and the fuel pump, the dispenser controller and a valve in the liquid fuel conduit, or the dispenser controller and a nozzle lift sensor of the dispensing unit.

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may be configured to detect the transmission of the output signal of the dispenser liquid fuel volume sensing device in a cable connected to the dispenser controller of the dispensing unit. In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may include a non-invasive current sensor, for example one or more of: a hall-effect sensor, a current transformer, a capacitively coupled signal sensor, or an inductively coupled signal sensor. It should be appreciated that signal conditioning

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PCT/NZ2017/050089 electronics may be required for transmission of the output of the vapour recovery liquid fuel volume sensing device to the at least one vapour volumetric flow controller. In an exemplary embodiment, the output signal of the sensor may be transmitted via an optical communication link.

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may be configured to detect the transmission of the output signal of the dispenser controller of the dispensing unit in a cable connected to a central fuel dispensing controller - for example in the forecourt shop area of the fuel dispensing facility.

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may be configured to determine liquid fuel flow volume through monitoring of acoustic signals produced by fluid flow or operation of dispensing unit equipment. For example, it is envisaged that the acoustic signals generated by mechanical movement of the fuel pump or flowmeter may be analysed to determine flow rate, and therefore volumetric flow rate.

By way of example, the acoustic sensor may be a fibre optic sensor such as a fibre optic microphone. Such fibre optic sensors may have particular application in the vapour recovery system of the present disclosure, with the optical sensing elements being noninvasive in terms of both size and use of electrical power.

In an exemplary embodiment, the acoustic signals may be analysed to evaluate performance of the fuel pump or flowmeter. For example, the acoustic signals may be used to assess a wear or degradation condition of the fuel pump or flowmeter. In exemplary embodiments this assessment may be used to, for example, issue alerts regarding the need for inspection of the part and potential preventative maintenance to be performed. In an exemplary embodiments detection of conditions associated with errors in operation of the vapour recovery system, or faults in the dispenser, may require the dispensing of the associated fuel to be disabled. In such embodiments the analysis of the acoustic signals may be used to detect such conditions.

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may include an optical encoder - for example using an optical chopper rotating with equipment associated with the liquid fuel flow, and a light emitter and receiver pair (potentially including light pipes routed from the non-hazardous area).

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may include an image capturing device (for example, a camera) configured to capture images of a fuel flow display of the dispensing unit. The images may be analysed to determine the rate of change of the characters displayed in the fuel flow display representing the volume of fuel dispensed, and therefore the volumetric flow rate of liquid fuel being dispensed.

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In an exemplary embodiment the at least one vapour recovery liquid fuel volume sensing device may operate independently from the dispenser liquid fuel volume sensing device.

In an exemplary embodiment the vapour recovery liquid fuel volume sensing device may be configured to determine liquid fuel flow volume by directly measuring liquid fluid flow in the dispenser delivery line - for example, using one or more of: a non-invasive sensor such as an ultrasonic flow sensor, a temperature sensor, a moving vane sensor, or a Coriolis flow sensor, or any sensor known in the art.

In an exemplary embodiment the vapour recovery system may include a wireless transmission device for wirelessly transmitting the output of the vapour recovery liquid fuel volume sensing device to the vapour volumetric flow controller.

In an exemplary embodiment the at least one vapour recovery liquid fuel volume sensing device may be calibrated by comparing its output signal to a measured volume of liquid fuel dispensed. In an exemplary embodiment the output from the dispenser liquid fuel volume sensing device may be used to calibrate the at least one vapour recovery liquid fuel volume sensing device.

In an exemplary embodiment, a diesel fuel delivery sensing device may be provided for transmission of a signal indicative of a selection of a diesel dispensing nozzle for a dispensing set to the vapour volumetric flow controller. The volumetric flow controller may be configured to inhibit the flow of vapour in the fuel vapour delivery conduit on receiving a signal indicative of a selection of a diesel dispensing nozzle.

It is envisaged that this may have particular application to exemplary embodiments in which the vapour recovery liquid fuel volume sensing device may not be capable of distinguishing between the flow of liquid diesel, and other fuel types to be dispensed from the dispensing set. At the time of filing the application, vapour recovery of diesel is generally not required. However, the inadvertent activation or control of vapour recovery based on the dispensing of diesel may result in certain conditions not being subsequently met - for example, an expected vapour flow rate returned from the associated vapour flow rate sensing device not being achieved within a predetermined time. This may be interpreted as a fault or error in the system. This may be avoided through prior knowledge of the currently dispensed fuel being diesel.

In an exemplary embodiment, detection of conditions associated with errors in operation of the vapour recovery system, or faults in the dispenser, may require the dispensing of the associated fuel to be disabled. In addition to reducing the likelihood of false errors as described above, by distinguishing between the selection of a diesel dispensing nozzle and other nozzles, the dispensing of diesel (which does not require vapour recovery) may be permitted regardless of the detection of such conditions.

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It should be appreciated that while this embodiment is described in the context of diesel, it may be applicable to the dispensing of any liquid fuel type not requiring vapour recovery from a dispenser also dispensing a liquid fuel requiring vapour recovery.

For a firmware and/or software (also known as a computer program) implementation, the techniques of the present disclosure may be implemented as instructions (for example, procedures, functions, and so on) that perform the functions described. It should be appreciated that the present disclosure is not described with reference to any particular programming languages, and that a variety of programming languages could be used to implement the present invention. The firmware and/or software codes may be stored in a memory, or embodied in any other processor readable medium, and executed by a processor or processors. The memory may be implemented within the processor or external to the processor.

A processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, state machine, or cloud computing device known in the art. A processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The processors may function in conjunction with servers and network connections as known in the art.

The steps of a method, process, or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by one or more processors, or in a combination of the two. The various steps or acts in a method or process may be performed in the order shown, or may be performed in another order. Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

FIG. 1 illustrates an exemplary vapour recovery system installed in an exemplary liquid fuel dispensing facility;

FIG. 2 is a schematic diagram of an exemplary liquid fuel dispenser;

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FIG. 3 is a schematic diagram of an exemplary vacuum pump unit;

FIG. 4 is a flow chart of an exemplary method for activation of the exemplary vacuum pump unit;

FIG. 5 is a flow chart of an exemplary method for control of an exemplary vapour recovery system.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary liquid fuel dispensing facility (fuel station 100) in which an exemplary vapour recovery system has been retrofitted. The fuel station 100 includes a plurality of liquid fuel dispensing units (dispensers 102) for dispensing liquid fuel stored in underground storage tanks 104.

A vapour pumping unit 106 of the vapour recovery system is connected to each dispenser 102 by vapour delivery conduits 108 and vapour recovery signal cables 110. In an exemplary embodiment in which the vapour delivery conduits 108 are substantially 25mm in diameter, the vapour pumping unit 106 is provided within 50m of the dispensers 102.

FIG. 2 shows a dispenser 102 to which components of the vapour recovery system have been retrofitted. The dispenser 102 includes a liquid fuel delivery line 200, connected to a fuel delivery control valve 202 and fuel pump 204. A dispenser flow meter 206 outputs a signal indicative of the volumetric flow rate of liquid fuel dispensed, transmitted via dispenser flow rate cable 208 to a dispenser controller 210. The dispenser controller 210 is also connected to the fuel delivery control valve 202 and fuel pump 204 by control cables 212 and 214 respectively.

As part of the installation of the vapour recovery system, the existing hose and nozzle are replaced with a coaxial hose 216 and coaxial nozzle 218, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit. A coaxial adapter 220 for each a coaxial hose 216 and coaxial nozzle 218 separates the liquid fuel dispensing conduit and a fuel vapour recovery conduit.

While not clearly seen in FIG. 2, it should be appreciated that each of the hose 216 and nozzle 218 combination illustrated may comprise a set of hoses and nozzles for dispensing different fuels. For example diesel, 91 octane petrol, 96 octane petrol and LPG may be dispensed from one side of the dispenser 102, with only one of the fuels dispensed at any one time. The vapour recovery conduits of each hose may be connected to a manifold (not clearly seen) connected to the vapour delivery conduit 108. There is commonly a set of nozzles and hoses on each side of each dispenser 102 hence two sets

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PCT/NZ2017/050089 per cabinet. Where there is a set of nozzles and hoses on each side of the fuel dispensing cabinet there are two vapour recovery ducts returning to the vapour pumping unit 106 from each dispensing cabinet.

A vapour recovery liquid fuel volume sensing device (VR fuel rate sensor 222) is positioned in the upper non-hazardous portion of the dispenser 102 in which the dispenser controller 210 is located, and configured to sense the signal in the dispenser flow rate cable 208 and in turn output a signal indicative of the volumetric flow rate of liquid fuel dispensed. In an exemplary embodiment the VR fuel rate sensor 222 may be galvanically isolated from the dispenser flow meter 206 and dispenser controller 210, for example a non-invasive current sensor such as a hall-effect sensor, a current transformer, a capacitively coupled signal sensor, or an inductively coupled signal sensor. A signal conditioning device 224 is provided in this exemplary embodiment, for transmission of the signal from the dispenser 102 to the vapour pumping unit 106 via vapour recovery signal cables 110.

In an alternative embodiment, sensing of the volumetric flow rate of liquid fuel dispensed may be provided by a dedicated fuel pump sensor 226 configured to monitor operation of the fuel pump or flow meter 206, or a fuel line sensor 228 configured to sense flow rate within the liquid fuel delivery line 200. In an exemplary embodiment, the fuel pump sensor 226 may be an acoustic sensor configured to output a signal indicative of the sound produced by the fuel pump or flow meter 206.

In exemplary embodiments, the vapour recovery system may include dispenser activation sensors 230 or 232 on the control cables 212 and 214 respectively, in order to provide a galvanically isolated means of determining that the dispenser 102 has been activated for dispensing of liquid fuel.

FIG. 3 shows an exemplary embodiment of the vapour pumping unit 106 of the vapour recovery system. For fuel stations having two-sided dispensers, each pair of vapour delivery conduits 108 is routed to the vapour pumping unit 106 and connected to first and second vapour flow rate sensors 300 and 302. Vapour volumetric flow control devices in the form of first and second proportional flow control valves 304 and 306 connect the first and second vapour flow rate sensors 300 and 302 to a secondary manifold 308. The respective secondary manifolds 308a and 308b of multiple vapour delivery conduits are connected to a primary pump manifold 310.

First and second vacuum pumps 312a and 312b are connected in series between the primary pump manifold 310 and a vapour return line 314 connected to the lowest octane fuel storage tank 104. The first and second vacuum pumps 312a and 312b operate to provide the vacuum to draw fuel vapour to the primary pump manifold, and push the fuel vapour through the vapour return line 314 to the lowest octane fuel storage tank 104. A non-return valve 316 and vacuum sensor 318 are provided between the first vacuum pump 312a and the primary pump manifold 310.

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In an exemplary embodiment, the vapour flow rate sensors 300 and 302, proportional flow control valves 304 and 306, secondary manifolds 308a and 308b, and primary pump manifold 310 are provided in a first housing 319a. In such an embodiment, the vacuum pumps 312a and 312b, non-return valve 316, and vacuum sensor 318 are provided in a second housing 319b.

The first housing 319a and second housing 319b may be located at some distance from each other. In one embodiment the first housing 319a and second housing 319b may be separate housings - i.e. distinct housings distanced from each other along the ground and having an airgap between them. In another embodiment the first housing 319a and second housing 319b may be compartments of a common housing - for example separated by at least one barrier and the second housing 319a potentially raised above ground level by a predetermined distance.

The vapour pumping unit 106 includes a controller 320 receiving signals from the components of the vapour recovery system at the dispensers 102 via the vapour recovery signal cables 110, from the first and second vapour flow rate sensors 300 and 302, and the vacuum sensor 318. Vacuum controller 322 is provided for control of the operation of the vacuum pumps 312a and 312b, and vapour recovery controllers 324 are provided for the control of proportional flow control valves 304 and 306. It should be appreciated that the controllers may be integral within the controller 320 - i.e. modules thereof - or distinct devices. It should be appreciated that the various controllers described may be physically located in different locations. For example, vacuum controller 322 may be provided at the housing 319b of the vacuum pumps 312a and 312b, while the vapour recovery controllers 324 may be provided at the housing 319a of the first and second proportional flow control valves 304 and 306. In another example, the controllers may be located separately from the other components of the vapour pumping unit 106.

In an exemplary embodiment, the vacuum controller 322 may operate the vacuum pumps 312a and 312b to maintain a constant vacuum level at the primary pump manifold 310, regardless of the number of vapour delivery conduits 108 open to the primary pump manifold 310.

However, in an exemplary embodiment if there is no fuel being dispensed the vacuum pumps 312a and 312b may be deactivated, or at least operated to maintain a lower than normal vacuum level, in order to reduce wear on those components and to reduce use of energy. When dispensing, and therefore vapour recovery, is required the vacuum pumps 312a and 312b must be run in order to restore the nominal operational vacuum level in order to achieve desired vapour volumetric flow rates. The length of the vapour delivery conduits 108 may be such that there is a delay before this is seen at the dispenser 102.

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When this delay may be relatively small, the dispensing of even a small amount of liquid fuel without vapour recovery in effect may result in an appreciable and potentially unacceptable percentage of vapour being lost.

FIG. 4 shows an exemplary method 400 of controlling the vacuum pump unit 106 to address potential issue. Where the vacuum pumps 312a and 312b are deactivated, the controller 320 receives a signal output from either of dispenser activation sensors 230 or 232 and determines that the associated dispenser 102 has been activated for the dispensing of liquid fuel in step 402. In step 404 the vacuum controller 322 may operate the vacuum pumps 312a and 312b to achieve the desired vacuum level. This essentially primes the pump manifold 310 for vapour recovery operation.

When the delay causes vapour to be lost from the fuel tank to the atmosphere or air to be sucked into the main storage tanks then the vacuum pump(s) need to be started prior to fuel being dispensed. This can be achieved by using nozzle lift sensors. However this means either tapping into an existing nozzle lift sensor system which means tampering with the existing system or adding in a new sensor into a hazard zone. Neither of these solutions are desirable due to safety and compliance issues.

FIG. 5 shows an exemplary method 500 of performing vapour recovery using the exemplary vapour recovery system retrofitted to the fuel station 100. In step 502, the controller 320 receives a signal from the VR fuel rate sensor 222 (or in alternative embodiments, the fuel pump sensor 226 or fuel line sensor 228) indicative of the flow rate of liquid fuel within the liquid fuel delivery line 200 of the associated dispenser 102.

In step 504, the controller 320 determines a target volumetric flow rate for vapour recovery through the associated vapour delivery conduit 108, based on the flow rate of liquid fuel. More particularly, the volume of vapour to be recovered is equivalent to the volume of liquid fuel being dispensed - the liquid fuel displacing fuel vapour as it enters the vehicle's fuel tank.

In step 506 the vapour recovery controller 324 controls the associated proportional flow control valve 304 or 306 to achieve the target volumetric flow rate. The output from the first and second vapour flow rate sensor 300 or 302 feeds back in a closed feedback loop to the vapour recovery controller 324 for control of the proportional flow control valve 304 or 306. Simultaneously, the vacuum controller 322 monitors the vacuum level at the primary pump manifold 310 and operates the vacuum pumps 312a and 312b to maintain the target vacuum level.

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

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Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or 5 indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments 10 described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Aspects of the present invention have been described by way of example only and it should be 15 appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

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Claims

1. A vapour recovery system configured to be retrofitted to a liquid fuel dispensing facility including at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source and at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit, the vapour recovery system including:

at least one dispensing unit nozzle and hose, each including a liquid fuel dispensing conduit and a fuel vapour recovery conduit;

at least one fuel vapour delivery conduit configured to be connected to the fuel vapour recovery conduit for delivery of fuel vapour to a storage tank;

at least one vapour recovery pump unit configured to be located remotely from the at least one liquid fuel dispensing unit, to provide a vacuum to the fuel vapour delivery conduit for transport of recovered vapour to the storage tank;

at least one vapour recovery liquid fuel volume sensing device galvanically isolated from the dispenser liquid fuel volume sensing device, and configured to output a signal indicative of the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit.

2. The vapour recovery system of claim 1, including a vacuum controller configured to control the vapour recovery pump unit to maintain a substantially constant vacuum at the fuel vapour delivery conduits during dispensing of liquid fuel.

3. The vapour recovery system of claim 2, including at least one fuel dispenser activation sensing device configured to output a signal indicative of the dispensing unit being activated to dispense liquid fuel.

4. The vapour recovery system of claim 3, wherein the vacuum controller is configured to maintain a reduced vacuum level when there is no demand for vapour recovery, and increase the vacuum level on receiving the signal indicative of the dispensing unit being activated to dispense liquid fuel.

5. The vapour recovery system of any one of claims 1 to 4, including at least one vapour volumetric flow control device configured to be controllable to adjust the volumetric flow rate through the fuel vapour delivery conduit.

6. The vapour recovery system of claim 5, including at least one vapour volumetric flow controller configured to receive the signal from the vapour recovery liquid fuel volume sensing device and control the vapour volumetric flow control device in accordance with the volume of liquid fuel being dispensed.

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7. The vapour recovery system of claim 6, wherein the at least one vapour volumetric flow controller is configured control the vapour volumetric flow control device to achieve a target volumetric flow rate through the fuel vapour delivery conduit substantially equivalent to the volumetric flow rate of liquid fuel being dispensed through the liquid fuel dispensing conduit.

8. The vapour recovery system of either claim 6 or claim 7, wherein the at least one liquid fuel dispensing unit includes a plurality of dispensing outlets, at least one of which is designated for delivery of diesel, and the system includes a diesel fuel delivery sensing device provided for transmission of a signal indicative of a selection of a diesel dispensing nozzle to the vapour volumetric flow controller, the vapour volumetric flow controller further configured to inhibit the flow of vapour in the fuel vapour delivery conduit on receiving the signal indicative of the selection of a diesel dispensing nozzle.

9. The vapour recovery system of any one of claims 1 to 8, wherein the vapour recovery liquid fuel volume sensing device is configured to detect the transmission of an output signal of the dispenser liquid fuel volume sensing device in a cable connected to a dispenser controller of the dispensing unit.

10. The vapour recovery system of any one of claims 1 to 8, wherein the vapour recovery liquid fuel volume sensing device is configured to detect the transmission of an output signal of a dispenser controller of the dispensing unit in a cable connected to a central fuel dispensing controller.

11. The vapour recovery system of any one of claims 1 to 8, wherein the vapour recovery liquid fuel volume sensing device is configured to determine liquid fuel flow volume through monitoring of acoustic signals produced by fluid flow through, or operation of, pumping equipment of the one liquid fuel dispensing unit.

12. The vapour recovery system of claim 11, configured to analyse the acoustic signals to evaluate performance of the pumping equipment of the one liquid fuel dispensing unit.

13. A kit set for retrofitting a liquid fuel dispensing facility to provide vapour recovery functionality, the liquid fuel dispensing facility including at least one liquid fuel dispensing unit for the dispensing of liquid fuel from a fuel source and at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit, the kitset including:

at least one vapour recovery pump unit configured to be located remotely from the at least one

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at least one vapour recovery liquid fuel volume sensing device configured to be galvanically isolated from the dispenser liquid fuel volume sensing device, and configured to output a signal indicative of the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit.

14. A liquid fuel dispensing facility, including:

at least one fuel source;

at least one liquid fuel dispensing unit for the dispensing of liquid fuel from the fuel source at least one dispenser liquid fuel volume sensing device for measuring the volume of liquid fuel dispensed by the liquid fuel dispensing unit;

a storage tank configured to receive fuel vapour; and at least one vapour recovery system as claimed in any one of claims 1 to 12.

15. A method of operating a liquid fuel dispensing facility retrofitted with a vapour recovery system, including:

receiving a signal indicative of a volume of liquid fuel being dispensed through a liquid fuel dispensing conduit of at least one liquid fuel dispensing unit from at least one vapour recovery liquid fuel volume sensing device galvanically isolated from a dispenser liquid fuel volume sensing device;

determining a target volumetric flow rate through a fuel vapour delivery conduit associated with the liquid fuel dispensing conduit, based on the volume of liquid fuel being dispensed through the liquid fuel dispensing conduit; and controlling a vapour volumetric flow control device associated with the fuel vapour delivery conduit to achieve the target volumetric flow rate in conjunction with a vacuum provided by at least one vapour recovery pump unit located remotely from the at least one liquid fuel dispensing unit, for transport of recovered vapour to a storage tank.

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FIG. 1

106

I

1/4

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102

FIG. 2

224

108

2/4

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FIG. 3

106

3/4

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FIG. 4

400

FIG. 5

500

4/4