AU2010226955B2 - Vapour Management System - Google Patents

Abstract

A vapour recovery system for use in a liquid dispensing environment, the system including a liquid dispenser including a liquid delivery line and a vapour recovery line; a vapour delivery line connected to the vapour recovery line; a container connected to the vapour delivery line and configured to receive vapour; a vapour pump unit configured to draw vapour into the container via the vapour recovery line and the vapour delivery line; and a controller configured to control operation of the vapour pump unit; the vapour recovery system characterised in that the vapour pump unit includes at least two pumps, and wherein the controller is configured to individually activate the pumps in accordance with a preset mode of operation. Eric o c C __M Qn C m C400 C rC

Description

VAPOUR RECOVERY SYSTEM TECHNICAL FIELD This invention relates to a vapour recovery system. In particular, the invention relates to a vapour recovery system for use in a liquid dispensing environment. BACKGROUND ART 5 Many volatile liquids evaporate and release vapour under various conditions relating to pressure and temperature. In many instances, it is desirable to retain the vapour and prevent it from being released into the environment. In particular, it is widely known that during normal operation, fuel dispensing systems release vapour which contains hydrocarbon and/or volatile organic 10 compounds. This vapour is harmful to the environment, and costly to consumers who pay for the fuel only to have a significant portion lost to the atmosphere in the form of vapour. The vapour is also potentially harmful to the personal health of users in terms of inhalation and risk of combustion. At the very least, the presence of the vapour creates a smell unpleasant to many people. 15 Vapour recovery systems have been developed which are intended to minimise the levels of vapour emissions released during delivery and dispensing of petroleum products. These are increasingly becoming mandatory under national regulations, in keeping with global trends towards environmental care. Vapour Recovery Stage 1 (VR1) systems deal with the process of delivering fuel 20 via tanker trucks to refuelling stations. Vapour Recovery Stage 2 (VR2) systems address the problems created during the

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dispensing of the fuel into customers' vehicles. In general, both systems implement a similar strategy for recovery of the vapour. In VR1 systems fuel is delivered from one hose, and vapour recovered with a second hose. 5 In VR2 systems, fuel is delivered via a first conduit in a coaxial hose. A negative pressure in the second conduit "sucks" any vapour produced during fuel delivery back into a storage tank. Previous VR2 systems have utilized two basic embodiments in creating the negative pressure required to recover the vapour. 10 In the first embodiment, the system uses a single central vacuum pump to create a site wide vacuum. Individual fuel dispensing pumps connect to the vacuum and deliver recovered vapour to a storage tank via a shared line. This design suffers from a number of issues, predominantly a lack of reliability. If the central vacuum pump fails, the vapour recovery system across the entire site becomes inoperable. 15 Further, it is difficult to control the vapour recovery flow rates at the individual fuel dispensing stations in order to account for the presence of an Onboard Refuelling Vapour Recovery (ORVR) system, or variation in fuel delivery rates. This typically results in the inefficient recovery of vapour. Where the flow rate is not great enough, vapour is released into the atmosphere. Conversely, an excessive flow 20 rate leads to an over-pressure situation in the storage tank, typically requiring venting of the tank and the associated release of vapour. In order to overcome these issues, some VR2 systems utilize individual pumps at each fuel dispensing station. These pumps may be adjusted individually with regard to flow rate in order to account for changes in environmental conditions or 2 the rate at which fuel is dispensed. If one pump fails, the remainder of the fuel dispensing stations may continue to operate normally. However, the increased costs in purchasing, running and maintaining such systems are significant. Further, the associated infrastructure in terms of piping and 5 monitoring becomes more complicated, with increased installation and maintenance costs and creation of additional points of failure. In terms of impact on the user, the ambient noise levels are raised due to the operation of an additional pump at the point of delivery. As in most consumer driven industries, it is highly desirable to minimise intrusion on a customer's 10 senses. As such, there is a need for a reliable and yet cost effective vapour recovery system. It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. 15 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 20 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. Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated 3 element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Further aspects and advantages of the present invention will become apparent 5 from the ensuing description which is given by way of example only. DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a vapour recovery system for use in a liquid dispensing environment, the system including: a liquid dispenser including a liquid delivery line and a vapour recovery line; 10 a vapour delivery line connected to the vapour recovery line; a container connected to the vapour delivery line and configured to receive vapour; a vapour pump unit configured to draw vapour into the container via the vapour recovery line and the vapour delivery line; and 15 a controller configured to control operation of the vapour pump unit; the vapour recovery system characterised in that the vapour pump unit includes at least two pumps, and wherein the controller is configured to individually activate the pumps in accordance with a preset mode of operation. 20 According to another aspect of the present invention there is provided a method of recovering vapour using a vapour recovery system for use in a liquid dispensing 4 environment, the method including the steps of: (i) dispensing liquid from a liquid delivery line; (ii) activating a vapour pump unit to draw vapour into a container via a vapour recovery line connected to a vapour delivery line; 5 the method characterised in that activating the vapour pump unit includes activating at least one of at least two pumps included in the vapour pump unit, wherein each pump can be individually activated, in accordance with a preset mode of operation. According to another aspect of the present invention, there is provided a method as 10 described above, including the step of: (iii) activating a flow control device to control the flow rate of vapour drawn into the vapour recovery line. Reference will be made throughout the specification to the liquid being a petroleum based fuel. However, it should be appreciated that the present invention may be 15 applied to any situation involving the transfer or delivery of volatile liquids. Volatile should be understood to mean evaporating readily at normal temperatures and pressures. "Normal" in the context of a fuel delivery system is likely to be atmospheric pressure, whereas normal conditions in a laboratory setting may be controlled dependent on the liquid being delivered. 20 Reference to a vapour recovery system should be understood to mean a system configured to capture vapour released during the transfer of volatile liquids, particularly petroleum based fuel. However, it should be appreciated that reference to the liquid being a petroleum based fuel is not intended to be limiting, and that 5 other applications are envisaged. For example, the present invention may be applied to the processing of alcohol, perfume and other products, whether in a manufacturing or laboratory testing environment. Reference to a dispenser should be understood to refer to a device configured to 5 release or deliver a set volume of liquid. In a preferred embodiment, the liquid dispenser is a fuel delivery system (colloquially known as a 'petrol or fuel pump'). Fuel Delivery Systems (FDS) may have a variety of operational characteristics, including source of fuel (remote or localised), delivery mechanism (gravity fed, pressure by way of integrated or remote pump, which may or may not be 10 mechanical), and number of delivery hoses. Stations having particular combinations of these features may be defined in the industry by alternative names to FDS (such as module, dispenser etc), but for the purposes of the present specification the term FDS will be used for all configurations. The FDS may be a Multiple Product Dispenser (MPD), capable of delivering one or 15 multiple products (such as diesel, LPG and/or petrol). In a preferred embodiment the dispenser includes a dispenser controller configured to control dispensing of the liquid from the dispenser. These dispenser controllers are well known, particularly in the fuel supply industry for controlling the volume and rate of fuel delivered to a user. 20 A controller as described within this specification may be implemented within one or more processors, micro-controllers, micro-processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digital signal processors (DSPs) or any other electronic device known to one skilled in the art and designed to perform the 25 functions described herein, or a combination thereof. 6 In a preferred embodiment the vapour recovery system includes a vapour recovery dispenser controller (VRDC) configured to control and/or monitor vapour recovery at the dispenser. Where an existing FDS is retrofitted with a vapour recovery system, the VRDC may 5 be configured to interface with existing dispenser controllers. These dispenser controllers are in communication with the point of sale of the fuel, and control the activation of the dispenser and the volume of fuel dispensed. A separate, intermediate interface between the VRDC and dispenser controller may be used in order to ensure compatibility. Alternatively, in new installations the VRDC may be 10 configured to incorporate the dispenser controller's functionality and therefore reduce the number of parts required. In a preferred embodiment the vapour recovery system includes a vapour recovery system controller (VRSC) configured to monitor and/or control the various other associated controllers, components and sensors, and also the vapour pump unit(s). 15 For example, it is envisaged that the vapour recovery system controller may be configured to monitor the container pressure and control venting of the container. Preferably the vapour recovery system is connected to a database and/or printer to log all operations of the vapour recovery system and provide reports as required. It is envisaged that the vapour recovery system controller may be configured to 20 enable or disable liquid dispensing. This may be site wide, or relative to individual liquid dispensers. Further, where the liquid dispenser is a Multiple Product Dispenser (MPD), the vapour recovery system controller may be configured to selectively allow dispensation of liquids which do not require vapour recovery. This may be particularly applicable when the vapour recovery system is not operational, 25 such as during a controlled shutdown. 7 The conditions required to be met before the vapour recovery system controller shuts down operation of a liquid dispenser and/or other components in the vapour recovery system may be set according to the particular specifications of a site, regulations, or company requirements. Various warnings or alarms may be 5 generated as a result of pressure within the container reaching a pre-defined limit, with respect to absolute or average pressure over a pre-defined period of time. Reference to a liquid delivery line should be understood to mean the line via which liquid is transferred from a stored location to the point of delivery. In the application of the present invention to a Stage 11 Vapour Recovery System, the point of delivery 10 will be a user's vehicle. Similarly, a vapour recovery line should be understood to mean the line via which vapour is initially transferred away from the point of delivery. Preferably the liquid delivery line and vapour recovery line are combined in a coaxial hose as known to those skilled in the art. It should be appreciated that the 15 lines need not be coaxial, and may be any other form of dual line known to those skilled in the art. Preferably the end of the hose is fitted with a hose nozzle adapted to be fitted to such dual/coaxial hoses, as known in the art. It is envisaged that the liquid deliver line and vapour recovery line may be connected to the coaxial hose by way of a coaxial adapter at the dispenser. 20 Reference to a vapour delivery line should be understood to mean the line via which recovered vapour is transferred from the dispenser to the container. It is envisaged that a plurality of vapour recovery lines may connect to the vapour delivery line. It is possible that in some embodiments having only one dispenser, the vapour recovery line and vapour delivery line may effectively be one line. 8 It should be appreciated that the vapour delivery line may not be continuous between the vapour recovery line and the container, but may be formed from a plurality of sections. It is envisaged that one section of the vapour delivery line may be connected to an inlet of the vapour pump unit, with the vapour being delivered to 5 the container via a separate section of the vapour delivery line connected to an outlet of the vapour pump unit. Reference to the vapour delivery line throughout the specification should be understood to be inclusive of a plurality of sections. In a preferred embodiment the vapour pump unit creates a negative pressure to draw the vapour through the vapour recovery line and a section of the vapour 10 delivery line between the vapour recovery line and the vapour pump unit. It should be appreciated that vapour drawn into the pump unit by the negative pressure will be delivered to the container via positive pressure. Although the vapour pump unit may include any number of pumps greater than two, it is envisaged that the vapour pump unit will include two pumps, capable of 15 servicing approximately 32 points of delivery. Preferably the vapour pump unit is contained in a sound insulated housing located remotely from the liquid dispenser(s). It is envisaged that the housing may also include a sump, as known in the art. The inlet and outlet of each pump in the vapour pump unit may be connected via 20 manifolds to the vapour delivery line. Preferably each pump includes a flame trap on both the inlet and outlet to isolate each pump from both the point of delivery and the container. It is envisaged that each pump may also include a one way valve on the inlet, to prevent the return of vapour to the point of delivery. It is envisaged that the vapour recovery system controller may be configured to 9 monitor and control the operation of the vapour pump unit. Alternatively, each vapour pump unit may include a dedicated vapour pump controller configured to monitor the negative vapour pressure and control the speed of the each pump. Such a vapour pump controller may be configured to interface 5 with the vapour recovery system controller which would maintain overall control. In a preferred embodiment, at least one of the pumps is activated on determining that a dispenser has been activated. When it has been determined that no dispensers are in operation, the pumps may be deactivated after a configurable run-on period. 10 The vapour pump controller(s) may be configured to control operation of the pumps to maintain a constant negative pressure in the vapour recovery and delivery lines regardless of the number of liquid dispensers being activated at any one point in time. The vapour recovery system controller may be configured to automatically detect 15 the number of vapour pump units (and pumps) connected to the vapour recovery system. It is envisaged that the motors of the pumps will be monitored continually in order that any gradual deterioration in performance may be observed. This may allow better decisions and prioritisation to be made regarding maintenance or 20 replacement of the pump. In particular, it is envisaged that each pump may have high and/or low current draw trip points set by a vapour recovery system operator, as known in the art. This may be achieved through the vapour recovery system or vapour pump controllers, or separate hardware configured to perform this function. 10 If a change in performance characteristics such as negative pressure levels or current draw meets pre-determined criteria, an alarm may be issued - whether a visual or audible alarm, or a flag in software indicating a fault. The pump associated with such an alarm condition may be shutdown until cleared by a 5 service technician. These alarms may also be activated in the event that a controller determines a fault in communications with the pump. Preferably, an individual pump may be manually switched in and out of operation in order to allow maintenance to be performed on that particular pump. The remaining pump(s) may continue to function, in order to ensure that operation of 10 the vapour recovery system is not disrupted. Further, it is envisaged that the selection of the pump(s) to be activated at any one time may be controlled according to a number of modes of operation, as described below. In a first mode, the run-time of each pump is monitored, and the pump with the 15 lowest run-time is activated on operation of a liquid dispenser. This enables "wear levelling" of the pumps, which may prolong their service life. It may be that a pump is selected for use in a first set time period (e.g. 24 hours), following which the pump having the lowest run-time is selected for use in the next set time period. In a second mode, one 'main' pump is selected for operation, with the other 20 pump(s) on standby for activation in the event that the 'main' pump fails or registers a fault. In a third mode, the pumps may be connected in series, and operate simultaneously to produce the required negative pressure. In doing so, it is envisaged that each pump may operate at lower speeds and hence extending the 11 working life of each pump. If one pump should fail, or operate at a lower efficiency, the other pump may be controlled to compensate for this. A person skilled in the art would appreciate that the various controllers associated with the system may be set to consistently operate in a particular mode, or may be 5 configured to determine the most appropriate mode for the detected conditions. It is also envisaged that each pump may be allocated to a particular liquid dispenser, or set of dispensers. The pump may be subsequently activated on operation of that liquid dispenser, or a dispenser in the set of dispensers In a preferred embodiment the vapour recovery system includes a condensate 10 drain valve connected between the inlet and outlet of the vapour pump unit. The condensate drain valve may be configured to open in response to the presence of condensate in the vapour delivery line, and allow the condensate to drain into the container. Under normal conditions the condensate drain valve is closed. The condensate drain valve may also be configured to convert the condensate back into 15 a gaseous state. In a preferred embodiment the container is an underground storage tank (UST). It should be appreciated that this is not intended to be limiting, and that the container may equally be an above ground tank. Further, the container may be made up of a plurality of interconnected containers as known in the art. 20 It is envisaged that the container may be the source of liquid dispensed from the liquid dispenser. However, this is not intended to be limiting as the container may equally be separate to the liquid source. In a preferred embodiment the vapour recovery system includes a pressure sensor configured to monitor the pressure of the container. 12 In the event that high container pressures are detected, the vapour recovery system controller may be configured to slow or stop operation of the vapour pump unit until the container pressure has subsided. Preferably the vapour recovery system also includes a pressure/vacuum (PV) valve 5 configured to vent the container as required. Preferably the vapour recovery system also includes an orifice plate for emergency venting, as known in the art. In a preferred embodiment, the vapour recovery system includes a vapour flow meter configured to measure at least the flow rate of recovered gas containing the vapour. Preferably the vapour flow meter also measures vapour temperature and 10 hydrocarbon concentration. Traditionally, vapour recovery systems have measured the gas-to-liquid ratio (widely known as air-to-liquid ratio or A/L) of a fuel dispenser in order to determine efficiency. Essentially, the volume of gas collected by a nozzle is compared with that of the volume of liquid (e.g. fuel). This methodology does not accurately 15 measure the vapour recovered by the system, as a significant proportion of the recovered gas may be air as opposed to vapour. It is envisaged that, where the vapour recovery system of the present invention is applied to a petroleum fuel dispensing application, the vapour flow meter will measure the hydrocarbon content of the recovered gas. 20 Where the vapour recovery system of the present invention is applied to a fuel dispensing environment, it is envisaged that the hydrocarbon content may be used to determine whether a user's vehicle has an Onboard Refuelling Vapour Recovery (ORVR) system in operation. If so, the vapour recovery system of the present invention may stop or reduce the rate of its own vapour recovery to ensure correct 25 and efficient operation. 13 It is envisaged that the vapour flow meter may be located in the vapour recovery line. However, in the event that multiple vapour recovery lines are connected to the vapour delivery line via a manifold, a single vapour flow meter may be positioned at the manifold to service the multiple vapour recovery lines. 5 In a preferred embodiment the vapour recovery system includes a flow control device configured to control the flow rate of gas being drawn into the vapour recovery line. Preferably the flow control device is a proportional valve as known in the art, although this is not intended to be limiting. In one embodiment, the flow control device is located between the vapour recovery 10 line and vapour delivery line. If multiple vapour return lines are connected to the vapour delivery line via the flow control device, the hose nozzles of the respective sets of vapour return and liquid delivery lines should include stop valves as known in the art for when that particular set is not delivering liquid. 15 Alternatively, in another embodiment the hose nozzles may be fitted with individual proportional valves as known in the art. It is envisaged that the flow control device may be used to conduct testing for leaks in the vapour return and delivery lines. The flow control device may be opened while liquid is not being dispensed, with the resulting air flow being indicative of the 20 presence and/or severity of a leak. Preferably the vapour recovery system includes a flow control device controller configured to control the flow rate through the flow control device. Preferably, the flow control device controller will receive information regarding the vapour flow rate from the vapour flow meter, directly or indirectly via connection to the vapour 14 recovery dispenser controller (VRDC). The flow control device controller may have a separate power supply to ensure correct operation independently of other components of the vapour recovery system, ensuring control of the flow control device at all times. 5 It is envisaged that a pulse correction module (PCM) may be used to determine and control the correct rate of pulsation of the flow control device to ensure efficient recovery of vapour. The pulse correction module may be configured to compensate for changes in vapour recovery rate due to physical effects such as temperature variation and/or swelling of hoses and seals in the system. 10 Preferably, the vapour recovery system includes a display. It is envisaged that the display will be connected to the vapour recovery system controller and output the status of individual liquid dispensers. The status information may pertain to flow rate, volume, vapour composition, faults detected, or any number of other parameters. 15 In a preferred embodiment the vapour recovery system includes at least one alarm. It is envisaged that the vapour recovery system controller may be configured to activate the alarm, however it should be appreciated that individual controllers such as the vapour recovery dispenser controller may be configured to activate an alarm in certain circumstances. 20 Preferably, the vapour recovery system is configured to communicate with a remote monitoring station. Remote monitoring of a vapour recovery system is required by some regulations surrounding the fuel dispensing industry. It is envisaged that virtually any information pertaining to the vapour recovery system may be accessed by way of the remote monitoring station. Further, the remote monitoring station 15 may issue instructions with regard to the operation of the vapour recovery system, such as venting of the container, disabling of liquid dispensing, or control of the vapour pump unit(s). The remote monitoring station may be located at a site or central office, a servicing 5 company office, or any other convenient location. It is envisaged that the remote monitoring station may be any internet enabled electronic device, such as a personal computer or PDA, and the associated software accessed by way of a webpage browser login as known in the art. Further, the remote monitoring station may be, or include, a database configured to record all information received. 10 The remote connection may be achieved by any method known to those skilled in the art, for example, a permanent Ethernet connection. It is envisaged that communication between the vapour recovery system and the remote monitoring station may be achieved by connection of the vapour recovery system controller to system integration middleware such as the PEC Ambient 15 Intelligent Monitoring (AIM) system. The PEC AIM, monitors communications between various sources in a fuel dispensing environment (including the vapour recovery system of the present invention) and includes an Ethernet connection for remote access. It should be appreciated that the various features discussed in relation to the 20 present invention being expressed as a method may also relate to a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer - commonly known as a computer program. A computer program may be accessible from any computer-readable or processor-readable device, carrier, or media. For example, computer-readable 25 medium can include but are not limited to magnetic storage devices, optical disks, 16 digital versatile disk (DVD), smart cards, and flash memory devices. The present invention provides the following advantages: * Reduced costs in installation and maintenance in terms of pumps and associated infrastructure in comparison with systems utilising individual pumps 5 per liquid dispenser, by providing a centralised vapour pump unit capable of servicing multiple liquid dispensers; " Increased reliability in comparison with systems utilising a single central pump by providing interchangeable pumps which may be switched in and out of operation on demand; 10 * Reduced maintenance and replacement costs by controlling operation of the pumps to carry out wear levelling; * Increased ease of maintenance by providing the ability to manually switch pumps in and out of service; " Efficient operation and scheduling of maintenance by continually monitoring 15 pump operation and hydrocarbon recovery to detect faults; * Reducing loss of profits and inconvenience to users by providing the ability to keep non-petrol hoses in a multiple product dispenser active during a controlled shutdown of the vapour recovery system. * Greater control and accountability by providing remote monitoring of system 20 from offsite location; " Low noise at the point of liquid delivery by remotely locating pump from liquid dispenser; and 17 * Minimising visual change from a user's perspective. 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 5 accompanying drawings in which: Figure 1 shows a vapour recovery system in accordance with one embodiment of the present invention; Figure 2 shows one configuration of a liquid dispensing station in accordance with one embodiment of the present invention; 10 Figure 3 shows a vapour pump unit in accordance with one embodiment of the present invention; and Figure 4 shows a vapour pump unit in accordance with another embodiment of the present invention. BEST MODES FOR CARRYING OUT THE INVENTION 15 Figure 1 shows a vapour recovery system (generally indicated by arrow 1) for use in a liquid dispensing environment in accordance with one embodiment of the present invention. The vapour recovery system (1) includes a liquid dispenser in the form of a Fuel Dispensing System (2). 20 The Fuel Dispensing System (2) includes a liquid delivery line (not shown) and a vapour recovery line (3). 18 The vapour recovery line is connected to a vapour delivery line (4). The Fuel Dispensing System (2) includes a dispenser controller (5). The dispenser controller (5) is configured to control the dispensing of fuel from the Fuel Dispensing System (2). 5 The Fuel Dispensing System (2) also includes a vapour recovery dispenser controller (6). The vapour recovery dispenser controller (6) is connected to the dispenser controller (5) by way of a vapour recovery dispenser controller interface (7). The vapour recovery dispenser controller (6) is configured to control and/or monitor vapour recovery at the Fuel Dispensing System (2). 10 The Fuel Dispensing System (2) further includes a vapour flow meter (8). The vapour flow meter (8) is configured to monitor the recovered vapour passing through the vapour recovery line (3). A flow control device in the form of a proportional valve (9) is also connected to the vapour recovery line (3) before the connection to the vapour delivery line (4). 15 The proportional valve (9) is in communication with a flow control device controller (10). The flow control device controller (10) is configured to control the flow rate through the proportional valve (9) by pulsing the valve open and closed at a set rate. The flow control device controller (10) is also provided with a flow control device 20 controller power supply (11). A pulse correction module (12) is in communication with the flow control device controller (10). The pulse correction module (12) is configured to ensure that the 19 pulsation of the proportional valve (9) compensates for physical changes in the system such as a temperature drop, and maintain the desired flow rate. The vapour recovery system (1) includes a container in the form of an underground storage tank (13), connected to the vapour delivery line (4). 5 A pressure sensor (14) is connected to the underground storage tank (13). The underground storage tank (13) is also connected to a pressure/vacuum (PV) valve (15) and an orifice plate (16). The pressure/vacuum (PV) valve (15) is configured to vent the underground storage tank (13) in the event that pressure exceeds a defined limit. 10 The vapour recovery system (1) includes a vapour pump unit (17), connected to the vapour delivery line (4) between the vapour recovery line (3) and the underground storage tank (13). The vapour pump unit (17) includes a first pump (18a), a second pump (18b) and a third pump (18c). 15 The three pumps (18a, 18b, 18c) are configured to be interchangeably activated to draw vapour through the vapour recovery line (3) and vapour delivery line (4) into the underground storage tank (13). The vapour recovery system (1) includes a condensate drain valve (19) connected to either side of the vapour pump unit (17). The condensate drain valve (19) is 20 configured to open in response to the presence of condensate in the vapour delivery line (4), and allow the condensate to drain into the underground storage tank (13). Under normal conditions the condensate drain valve (19) is closed. The vapour recovery system (1) includes a vapour recovery system controller (20). 20 The vapour recovery system controller (20) is connected to the vapour recovery dispenser controller (6), dispenser controller (5) by way of vapour recovery dispenser controller interface (7), pressure sensor (14), and vapour pump unit (17). The vapour recovery system controller (20) is configured to monitor and control the 5 activation of the vapour recovery system (1). The vapour recovery system controller (20) is located at a central location, provided for in this embodiment by a service station shop (21). The shop (21) includes a point of sale interface (22). The point of sale interface (22) is in communication with the dispenser controller (5) to provide direction as to 10 the volume of fuel to be dispensed. Operation of the vapour recovery system (1) is as follows. A user (not shown) activates the Fuel Dispensing System (2), having been authorized by the point of sale interface (22). Fuel is dispensed through the liquid delivery line (not shown), into the users vehicle (not shown). 15 Simultaneously, the vapour recovery system controller (20) activates one of the three pumps (18a, 18b, 18c), which creates a negative pressure in the vapour delivery line (4) on the side connected to the vapour recovery line (3). The proportional valve (9) is pulsed open and closed by flow control device controller (10) in conjunction with the pulse correction module (12). 20 This creates a flow of vapour in the vapour recovery line (3), sucking vapour released during delivery of the fuel into the vapour recovery line (3). The flow of vapour in vapour recovery line (3) is monitored for flow rate and hydrocarbon content by vapour flow meter (8). 21 The vapour travels through the vapour delivery line (4) until it is contained in the underground storage tank (13). Once delivery of fuel has ceased and all vapour collected, the proportional valve (9) is closed and pumps (18a, 18b, 18c) turned off. The vapour recovery system controller (20) is used to select a mode of operation 5 for each of the three pumps (1 8a, 18b, 18c). In a first mode, the run-time of each pump (18a, 18b, 18c) is monitored, and the pump (18a, 18b, 18c) with the lowest run-time is activated on operation of the Fuel Dispensing System (2). This enables "wear levelling" of the pumps (18a, 18b, 18c). In a second mode, the first pump (18a) is selected for operation, with the second 10 pump (18b) and third pump (18c) placed on standby for activation in the event that the first pump (18a) fails or registers a fault. In a third mode, the pumps (18a, 18b, 18c) are connected in series and are activated simultaneously to achieve the desired negative pressure. If one pump fails, the operation of the others is adjusted to compensate. 15 The vapour recovery system controller (20) is configured to record conditions associated with the vapour recover system (1). An example of the conditions which may be set is as follows: type A - underground storage tank (13) pressure outside range -2.OkPa to +0.75kPa for at least 30 minutes in a day; 20 type B - underground storage tank (13) pressure outside range -2.5kPa to +1.25kPa for at least 3 minutes; type C - underground storage tank (13) pressure inside range -50Pa to +50Pa for at least 23 hours in a day. 22 The vapour recovery system controller (20) is configured to shut down operation of the Fuel Dispensing System (2) in the event that a condition is recorded over a predetermined period. Examples of such predetermined periods are: (i) type A warning condition is detected for 30 consecutive days; 5 (ii) type B warning condition is detected for 7 consecutive days; (iii) type C warning condition is detected for 7 consecutive days. The vapour recovery system controller (20) and the vapour recovery dispenser controller (6) are connected to a display (23). The display (23) is configured to output status information relating to vapour flow rate, volume, vapour composition, 10 and faults detected for the Fuel Dispensing System (2). The vapour recovery system (1) includes an alarm (24). The alarm (24) is connected to the vapour recovery system controller (20) and is used to alert an operator to a fault in the system, for example pump failure or tank overpressure. The vapour recovery system controller (20) is connected to a remote monitoring 15 station (25) via integration middleware in the form of a PEC Ambient Intelligent Monitoring (AIM) system (26). The remote monitoring station (25) receives all data created by the vapour recovery system (1), and is configured to issue instructions to the vapour recovery system controller (20). 20 Figure 2 illustrates a configuration of various components of a Fuel Dispensing System (2) of figure 1. 23 The Fuel Dispensing System (2) includes two sets of three outer fuel delivery lines (not illustrated) and three vapour recovery lines (30). Each set of a liquid delivery line and a vapour recovery line (30) connects to a coaxial hose (31) via a coaxial adapter (32) 5 Each coaxial hose (31) is fitted with a hose nozzle (33). Each hose nozzle (33) includes a stop valve (not illustrated) which is closed to prevent fluid flow through the vapour recovery line (30). Numerous coaxial safety breaks (34) are fitted in each coaxial hose (31) in order to prevent damage to the coaxial hose (31) or Fuel Dispensing System (2) in the 10 event that the coaxial hose (31) is pulled excessively. Each coaxial hoses (31) passes through a hose bend assembly (35) to locate the coaxial hoses (31) overhead and prevent kinking. Each set of three vapour recover lines (30) passes through a vapour flow meter (36) and proportional valve (37) before passing through a dispenser manifold (38) 15 and into a vapour delivery line (39). The vapour delivery line (39) is connected to a vapour pump unit (not illustrated) which creates a negative pressure in the vapour delivery line (39). In operation, fuel is delivered via at least one of the fuel delivery lines. The stop valve of the appropriate hose nozzle (33) is opened, as is the proportional valve 20 (37) responsible for the vapour recovery line (30) paired with the fuel delivery line. As fuel is delivered and vapour is produced, the vapour is sucked through the nozzle (33), coaxial hose (31), coaxial adapter (32), vapour flow meter (36), 24 proportional valve (37), and the dispenser manifold (38) into the vapour delivery line (39). Once fuel has stopped being delivered, the stop valve and proportional valve (37) are closed. 5 Figure 3 illustrates one configuration of a vapour pump unit (generally indicated by arrow 100). The vapour pump unit (100) includes a housing (101). The housing (101) includes an inlet (102) and an outlet (103). Also contained within the housing are three pumps (104a, 104b, 104c). 10 Each pump (104a, 104b, 104c) includes a pump inlet (105) and a pump outlet (106). The pump inlet (105) and pump outlet (106) of each pump (104a, 104b, 104c) are connected to the inlet (102) and outlet (103) respectively, via two manifolds (107). The pump inlet (105) and pump outlet (106) of each pump (104a, 104b, 104c) 15 includes a flame trap (108). Further, the pump inlet (105) of each pump (104a, 104b, 104c) includes a one-way valve (109). The vapour pump unit (100) is controlled to operate in accordance with the first and second modes described with reference to vapour pump unit (17) of figure 1. Figure 4 illustrates another configuration of a vapour pump unit (generally indicated 20 by arrow 200). The vapour pump unit (200) includes two pumps (201a, 201b). Each pump (201a, 201b) includes a pump inlet (202a, 202b) and a pump outlet (203a, 203b). 25 One-way valves (204a, 204b) are positioned at the inlets (202a, 202b) of both pumps (201a, 201b). Additional one-way valves (204c, 204d) are also positioned between the inlet (202a, 202b) and outlet (203a, 203b) of both pumps (201a, 201b). 5 The vapour pump unit (200) is controlled to operate in accordance with the third mode described with reference to vapour pump unit (17) of figure 1. In normal operation, one-way valves (204c, 204d) are closed, while one-way valves (204a, 204b) are open. Both pumps (201a, 201b) are then operated simultaneously at a lower speed to achieve the desired negative pressure. 10 Should pump (201a) fail or be determined as malfunctioning, valve (204a) is closed and valve (204c) opened to bypass pump (201a). The speed of pump (201b) is then adjusted to achieve the desired negative pressure. Conversely, if pump (201b) fails or is determined to be malfunctioning, valve (204b) is closed and valve (204d) opened to bypass pump (201b). The speed of pump 15 (201a) is then adjusted to achieve the desired negative pressure. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 26

Claims (19)

1. A vapour recovery system for use in a liquid dispensing environment, the system including: a plurality of liquid dispensers, each including a liquid delivery line and a vapour recovery line; at least one vapour delivery line connected to the vapour recovery lines; a container located remotely from the liquid dispensers, connected to the at least one vapour delivery line and configured to receive vapour; a vapour pump unit including at least two pumps, the vapour pump unit located remotely from the liquid dispensers, and configured to draw vapour into the container via the vapour recovery lines and the vapour delivery line; and a controller configured to control operation of the vapour pump unit, wherein the controller is configured to individually operate the pumps in accordance with a preset mode of operation.

2. The vapour recovery system as claimed in claim 1, wherein the controller is configured to monitor performance characteristics of the pumps.

3. The vapour recovery system as claimed in claim 2, wherein each pump has pre determined high and/or low current draw trip points.

4. The vapour recovery system as claimed in either claim 2 or claim 3, including an alarm configured to issue if a change in the performance characteristics meets pre determined criteria. 27 James & Wells Ref: 130703AU/73

5. The vapour recovery system as claimed in any one of claims 1 to 4, wherein the controller is configured to enable a user to manually switch individual pumps in and out of operation, while controlling the remaining pump(s) to continue functioning.

6. The vapour recovery system as claimed in any one of claims 1 to 5, wherein the controller is configured to implement a mode of operation in which the controller monitors each pump for run-time, and operates the pump with the lowest accumulated run-time on operation of the liquid dispenser.

7. The vapour recovery system as claimed in any one of claims 1 to 5, wherein the controller is configured to implement a mode of operation in which the controller selects one pump for operation, and places the other at least one pump on standby for operation in the event that the selected pump fails or registers a fault.

8. The vapour recovery system as claimed in any one of claim 1 to 5, wherein the pumps are connected in series.

9. The vapour recovery system as claimed in claim 8, wherein the controller is configured to to implement a mode of operation in which the pumps are controlled to compensate for failure, or operation at a lower efficiency, of any one pump.

10. A method of recovering vapour using a vapour recovery system for use in a liquid dispensing environment, the method including the steps of: dispensing liquid from a liquid delivery line of at least one of a plurality of liquid dispensers, wherein each of the liquid dispensers includes a vapour recovery line connected to a vapour delivery line; operating a vapour pump unit to draw vapour into a container located remotely from the liquid dispenser, via the vapour recovery line of the at least one liquid dispenser, and the vapour delivery line, 28 James & Wells Ref: 130703AU/73 wherein the vapour pump unit is located remotely from the liquid dispenser and includes at least two pumps, and operating the vapour pump unit includes selectively operating at least one of the at least two pumps in accordance with a preset mode of operation.

11. The method of recovering vapour as claimed in claim 10, including monitoring performance characteristics of the pumps.

12. The method of recovering vapour as claimed in claim 11, including setting pre determined high and/or low current draw trip points for each pump.

13. The method of recovering vapour as claimed in either claim 11 or claim 12, including issuing an alarm if a change in the performance characteristics meets pre determined criteria.

14. The method of recovering vapour as claimed in any one of claims 10 to 13, wherein the mode of operation includes monitoring each pump for run-time, and operating the pump with the lowest accumulated run-time when liquid is dispensed from the liquid delivery line.

15. The method of recovering vapour as claimed in any one of claims 10 to 13, wherein the mode of operation includes selecting one pump for operation, with the other at least one pump placed on standby for operation in the event that the selected pump fails or registers a fault.

16. The method of recovering vapour as claimed in any one of claim 10 to 13, wherein the pumps are connected in series, and are operated simultaneously.

17. The method of recovering vapour as claimed in claim 16, wherein the mode of operation includes controlling operation of the pumps to compensate for failure or operation at a lower efficiency of any one pump. 29 James & Wells Ref: 130703AU/73

18. A vapour recovery system as herein described with reference to and as illustrated by the figures and accompanying description.

19. A method of recovering vapour as herein described with reference to and as illustrated by the figures and accompanying description. 30