Abstract:
A dumping well including a tank, upper and lower liquid level detectors, and a dump valve operated by pressurized fluid. The dumping well dumps liquid from the tank in response to liquid reaching an upper liquid level and ceases dumping liquid upon the liquid reaching a lower liquid level.

Description:
TECHNICAL FIELD 
       [0001]    Dumping well apparatus and dumping method 
       BACKGROUND 
       [0002]    In a typical dumping well arrangement a displacer is suspended in a tank. When the fluid level rises in the tank fluid buoyancy lifts the displacer plugging an orifice in a control box attached to the tank. While open the orifice bleeds off a supply of pressurized gas, such as pressurized air or natural gas, and once the orifice is plugged there is a build-up of pressure which opens a dump valve connected to the tank. Opening the dump valve allows fluid to exit the tank, causing the fluid level to fall along with the displacer. The lowering of the displacer opens the orifice in the control box, allowing the pressurized air to vent out, releasing the built-up pressure and allowing the dump valve to close. This procedure cycles frequently, dumping only small volumes of fluid on each cycle and wasting large volumes of pressurized gas. 
       SUMMARY 
       [0003]    In an embodiment, there is disclosed a dumping well comprising a tank for containing a liquid, an upper liquid level detector for detecting an upper liquid level in the tank, a lower liquid level detector for detecting a lower liquid level in the tank, a dump valve for dumping liquid from the tank and a control system for opening the dump valve in response to the upper liquid level detector detecting an upper liquid level in the tank, and for closing the dump valve in response to the lower liquid level detector detecting a lower liquid level in the tank, in which the dump valve is operated by a pressurized fluid, and the control system is configured to open the dump valve by opening a control valve connecting the dump valve to a supply of pressurized fluid and to close the dump valve by closing the control valve. 
         [0004]    In various embodiments, there may be included any one or more of the following features: the control valve may be a solenoid valve, the solenoid valve may be a pulse solenoid valve, the control system is a flip flop relay connected to control the pulse solenoid valve, there may be a float and the upper liquid level detector and lower liquid detector may be configured to detect the level of the liquid by detecting the level of the float, the float may be in a float bridle connected to the tank, the float bridle may have at least an upper and lower connection to the tank, the upper and lower liquid level detectors may be magnetic proximity detectors and the float may comprise a magnet, the float bridle may be substantially non-magnetic and may be made of stainless steel, there may be a flow rate valve connected to an outlet of the dump valve and the flow rate valve may be a globe valve, the supply of pressurized fluid may be a pressurized air tank, the pressurized air tank may be supplied with pressurized air from an air compressor, the air compressor may be powered by a solar panel. 
         [0005]    In an embodiment there is disclosed a method of dumping a liquid from a tank comprising detecting the liquid reaching an upper liquid level, operating a dump valve with pressurized fluid in response to the liquid reaching a first liquid level, detecting the liquid reaching a lower liquid level and closing the dump valve in response to the liquid reaching the second liquid level. In a further embodiment the pressurized fluid is pressurized air and in a further embodiment the pressurized fluid is pressurized gas. 
         [0006]    These and other aspects of the device and method are set out in the claims, which are incorporated here by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0007]    Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which: 
           [0008]      FIG. 1  is a schematic of an exemplary dumping well configuration. 
           [0009]      FIG. 2  is a schematic of a pressurized gas tank with an air compressor and solar panel. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims. 
         [0011]    In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite articles “a” and “an” before a claim feature do not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims. 
         [0012]    Referring to  FIG. 1 , there is shown a tank  10  containing liquid to be dumped. The tank  10  is connected by upper pipe  12  to a float bridle  16  containing a float  18 . The float  18  may include a flotation component  30  and a permanent magnet component  32 . In an embodiment the float is a pressurized canister float with a permanent magnet clamped to its bottom end. The float is pre-pressurized to prevent it from being crushed at operating pressures. Associated with float bridle  16  is an upper liquid level detector  20  and a lower liquid level detector  22 . In this shown embodiment the upper and lower liquid level detectors are magnetic proximity detectors. The upper liquid level detector and the lower liquid level detector connect to a control system  25  which controls a flow of pressurized air to open the dump valve in response to the upper liquid level detector detecting an upper liquid level in the tank, and close the dump valve in response to the lower liquid level detector detecting a lower liquid level in the tank. The control system  25  may comprise a control switch  24  which controls an air flow control valve  34 . In a preferred embodiment the control switch  24  is a flip-flop relay switch and the air flow control valve  34  is a pulse solenoid valve. In this embodiment the air flow control valve  34  controls air flow through tube  38  from a pressurized air tank  50  (shown in  FIG. 2 ) to a dump valve  26 . The air flow control valve  34  may be a three way valve configured to allow air flow from the pressurized air tank  50  when the air flow control valve  34  is open and to bleed air pressure between the air flow control valve  34  and the dump valve  26  when closed. The dump valve  26  receives fluid through lower pipe  14  from tank  10  and float bridle  16 . The outlet of dump valve  26  is also connected by lower pipe  14  to flow rate valve  28 . The flow rate valve throttles the flow of fluid through lower pipe  14  and, in a preferred embodiment, the flow rate valve  28  is a globe valve. A generic valve symbol is used in  FIG. 1  to represent each of the dump valve  26 , flow rate valve  28 , air flow control valve  34  and bleed valve  36 . 
         [0013]    Referring to  FIG. 2 , there is shown a pressurized air tank  50  which receives pressurized air from an air compressor  52  through tube  38 . The air compressor  52  is powered by a solar panel  54  and associated with the solar panel  54  is a charge regulator  56  and a battery  58 . Although a solar panel arrangement is shown, many conventional power sources could be used to power the air compressor. The air compressor  52  is controlled by a pressure switch  60  which activates the air compressor  52  upon detecting that the air pressure in the pressurized air tank  50  is below a lower threshold and deactivates the air compressor upon detecting that the air pressure in the tank is above an upper threshold. In the figure an air dryer  62  is connected to an air inlet  64  and the air compressor  52 . The air dryer  62  serves to remove moisture from the intake air and, in one preferred embodiment, is a desiccant bead air dryer. 
         [0014]    During operation of the dumping well, the dump valve  26  starts in a closed position. Liquid enters the tank  10  raising the liquid level in the tank  10 . Upper pipe  12  and lower pipe  14  connect the tank  10  and float bridle  16 , allowing equalization of liquid level. The float  18  rises with the liquid level in the float bridle  16  and is eventually detected by the upper liquid level detector  20 . The upper liquid level detector then triggers control switch  24 . The control switch  24  switches the air flow control valve  34  from a closed position to an open position and switches the bleed valve  36  from an open position to a closed position. Opening the air flow control valve  34  allows pressurized air from the pressurized air tank  50  to travel through tube  38  to the dump valve  26 . The pressurized air moves the dump valve  26  from a closed position to an open position and allows liquid to exit the tank  10  and float bridle  16  through the lower pipe  14 . A flow rate valve  28  limits the rate at which liquid is able to exit through pipe  14 . The degree to which the flow rate valve  28  reduces the flow rate should be calibrated to ensure that there is no net flow into the tank  10  when the dump valve  26  is open. 
         [0015]    As liquid exits the tank  10  and float bridle  16  the liquid level falls and with it the float  18 . When the float reaches the level of the lower liquid level detector  22 , the detector  22  triggers the control switch  24  which now closes the air flow control valve  34  and opens the bleed valve  36 . Opening the bleed valve  36  allows bleeding of air pressure at the dump valve  26 , prompting the dump valve  26  to close and therefore preventing liquid from exiting the tank  10  and fluid well  14 . Further liquid entering the tank  10  will then cause the liquid level to rise, allowing the process to repeat. 
         [0016]    While the system is described as using pneumatic power to control the dump valve, it would be apparent that hydraulic power could be used to accomplish a similar result.