Editorial Note 2014100666 There are 4 pages of description Applicant Thomas Kress CONTROL SYSTEM AND METHOD FOR AN AIRLIFT PUMP FIELD OF THE INVENTION This invention relates to a system and method for controlling the transport of a liquid by using compressed air. In particular it relates to the management of air used in the system by detecting flows and electronically manipulating flow paths via automatic valves. This invention has been developed primarily for use as a system for lifting a liquid such as water or oil from a subterranean source such as a well or bore or from a mine. It may however also be applied in other situations, such as in lifting water from a lake or creek to a higher discharge point and will be described hereinafter with reference to these applications. It will be appreciated, however, that the invention is by no means limited to these particular fields of use. BACKGROUND TO THE INVENTION Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known, or forms part of the common general knowledge in the field. Compressed air is used to drive a pump unit while an air supply management mechanism directs air to the pump unit or interrupts the supply while venting air from the unit, so as to allow it to take in water. The water is then expelled by restoring the air supply to the chamber and allowing pressure to build. The pump unit comprises a chamber suitable for a specific requirement. It has a non-return valve at its lower end which opens under the force of superior pressure to admit water under the force of the hydraulic head available according to the depth of submersion of the unit. Air is injected into the chamber through an inlet at the upper end and pressurizes the chamber sufficiently to close the non-return valve and prevent more water entering. The air pressure is then allowed to increase to the extent needed to force the water that has gathered in the chamber up and out through a discharge port into a delivery pipe. As the air propels the water up and along the delivery pipe, the pressure in the chamber drops and some of the water drops back. To prevent this water dropping all the way back into the chamber again, a second non-return valve is provided in the outlet conduit leading from the pump chamber. OBJECT OF THE INVENTION It is an object of the invention (in its preferred form) to provide a pump management system in which the pumping operation is automated by sensing air flow to the management system and periodic vent flow from the chamber. Still further, it is an object of the invention to provide a method and system which is operable with a minimal number of inputs needed from a human operator, enabling it to be operated virtually unattended after start-up.
SUMMARY OF THE INVENTION According to the invention there is provided a management system for managing the functioning of an airlift pumping device, which has a body having an internal chamber in fluid communication with water to be pumped and connected to a supply line for receiving compressed air, said system comprising: a detection device for detecting availability of compressed air for expelling water from the chamber and electronic control means configured to enable and disable air flow to and from the pump chamber; the control means comprising logic that has been programmed on startup to detect an input responsive to compressed air being present in the supply line, and in response to actuate automatically a purge function, thereby to reduce initial liquid load and subsequently to ignore further changes of state of said flow device until said circuit has been continuously open for a pre-set period of time. In a preferred form of the invention, the management apparatus comprises a purpose built electronic controller with inputs from 2 flow devices and one variable timer and outputs to 2 solenoid valves, which manipulate air flow to and from the pump chamber. In an embodiment, the management apparatus further includes means for causing a delay in the cycling of the air supply to the pumping device for a first preset period during which liquid is expelled from the chamber and piping to reduce the liquid load and prevent possible stalling due to high required air pressure by forcing liquid from the pumping device and cause it to travel into and along the discharge pipe. Preferably the first phase, which starts when the inlet flow device detects an air flow by a closed circuit in the detection device and remains actuated via the logic by ignoring any change of state until said circuit remains open for a preset period of time, is for discharging liquid from the pumping device and the second phase is for recharging the device with liquid to be lifted. According to a second aspect of the invention there is a method of starting up an airlift pumping device which has a body having an internal chamber for receiving air and water, wherein the method comprises the steps of: 1. Providing said airlift pumping device and connecting it to an input line for receiving compressed air; and to a delivery pipe for outputting water; 2. Installing in the input line a valve operable to enable and disable air supply to the pumping device, 3. Immersing the pumping device in water to be pumped, 4. Allowing water to occupy the chamber and enter at least a portion of the delivery pipe, so that a static head is defined in the pipe above the pumping device, and above the water; 5. With the valve open, allowing air pressure in the input line to increase to a value exceeding the static head for a predetermined period of time for allowing the pressurized air to enter and purge water from the chamber and delivery pipe, thereby reducing the static head, 6. Thereafter causing the valve to open according to a predetermined timed cycle and then close while a second valve opens to atmosphere until a flow device in a vent line to atmosphere detects the cessation of air being vented, signaling that the chamber is full with a discrete quantity of water to be subsequently pumped out. SUMMARY OF THE DRAWINGS In order that the invention may be readily understood, and put into practical effect, reference will now be made to the accompanying drawings in which: Figure 1 is a schematic view of a preferred embodiment of the air supply management system according to the invention. Figure 2 is a flowchart illustrating the main logic process of the method of the invention when applied in conjunction with the components of figure 1. DETAILED DESCRIPTION OF THE INVENTION The invention provides a system and method for managing the air flows to an airlift pump device, by using air pressure to clear the fluid from the chamber by pushing it up the outlet into a piping system. Then the chamber is vented, allowing it to re-fill. The venting is stopped once air flow to atmosphere stops, meaning the chamber is full and ready for clearing once more to the delivery piping. With reference to figure 1, there is shown a pumping system in which a pump chamber 8 is submerged in a body of fluid down a vessel or bore. Above ground level is a compressor 7 which supplies air to the pump chamber 8 through an on/off solenoid valve 4. As air flows through flow device 3, it senses the air flow from compressor 7, initiating the sequencing of the management system. Valve 4 is of normally open configuration, meaning that unless energised, it is in a fail open position. Controller 2 includes a pre-programmed electronic device, as well as a simple adjustable timer input, which is set to determine the length of the pumping (clearing) cycle. Valve 5 is of normally closed configuration, meaning that unless energised, it is in a fail-closed position. Valves 4 and 5 are supplied with electrical current via cables from the electronic controller 2, to actuate them to open position for valve 5 and closed position for valve 4. When valve 4 is open, valve 5 is closed to allow air from the compressor 7 to pass through the air supply pipe to pump chamber 8. After a preset interval, the timer device component of the electronic controller switches power over to energize valve 4 and 5. The change interrupts air flow to the pump chamber 8, which is now at a pressure higher than atmospheric. When valve 5 is energised to open, the air in the chamber, under positive pressure and further under pressure exerted by the head of fluid in the vessel/bore, is able to escape and be vented via valve 5 to atmosphere. As the air escapes, the pressure in the chamber 8 decreases, permitting fluid to enter from the vessel/bore and recharge the chamber 8. Once the air flow to vent stops, the flow device 6 sends a signal to electronic controller 2, initiating de-energising of valves 4 and 5 for the next clearing step to force fluid from chamber 8 to the delivery piping system. Programmed into the electronic controller 2 is a purge cycle, which allows air to the chamber 8 in order to clear out the initial load of fluid prior to the start of cycling and thus preventing stacking up of excessive fluid in the delivery piping, causing the requirement of excessive pressure to keep lifting the fluid and over working the compressor. Further programmed into the electronic controller 2 is a means to prevent frequent re-starting of the sequence due to change of state of flow device 3 due to low air flow or upsets in air flow. This means is a timing device that once initiated will keep the sequence going un-interrupted until the flow device 3 remains in a pre-set condition for a pre-set period. The control device is powered from an electrical power source. This may be a battery or a solar panel, or a battery replenished by a solar panel. Mains power may also be used via a voltage adjusting device. The control device thus includes an electronic control device which receives the signals from the sensing devices 3 and 6, as well as an adjustable timing device, which is part of the device 2. The type of airlift pump chamber used for receiving and expelling the liquid is not crucial to the operation of the invention. Two suitable examples, are types marketed by Brumby Pumps and Airwell Pumps. The casing defines an inner space into which air is injected through an inlet at an upper end. The internal annulus pipe extends from the upper end, where it connects with delivery piping, to a point near the bottom of the chamber. At the lower end of the chamber there is an inlet valve which is openable to admit liquid from the outside. In this embodiment, the valve is a floating ball valve, but may conveniently comprise an alternative mechanism such as a hinged flapper or gland. A second non-return valve is installed in the discharge conduit, or in the internal annular pipe leading to it. The function of this non-return valve is to prevent liquid pushed up into the discharge line from returning to the pump chamber when the air supply is interrupted to allow fresh liquid to enter the chamber unimpeded by remnants of an earlier batch of liquid.