The Pump Wizard    |    Submersible Pump Overview    |    Feature Comparison Table    |    Cost Comparison Chart Home > Pump Overview > Air Powered Leachate and condensate pumping can be difficult because of explosion hazards, corrosive liquids, solids, solvents, and viscous fluids. Air-powered pumps were designed specifically to meet these conditions while providing built-in level control. Automatic air-powered pumps use an internal float mechanism to activate an air valve inside the pump. The air valve alternately pressurizes the pump cavity to drive the fluid out, then exhausts the pump cavity to let it refill by hydrostatic pressure. A complete system consists of the pump, the air supply and discharge tubing and wellhead cap. Pumps are available in a range of diameters, lengths, top and bottom inlets and materials. Image: How it works The air-powered pump mechanisms have been highly developed to provide long-term reliability and durability under difficult well conditions, and are commonly backed up by multi-year warranties. The advantage of this design is that the "heavy lifting"- pumping the liquid- is performed by fluid-on-fluid (air on water), so there is inherently less mechanical load and wear on key components than with other designs. Filling an air-powered automatic pump with silt or sand may stop it but does not damage it. Air-powered automatic pumps feature large internal clearances in the major fluid passages (i.e. large intake and discharge valves), that allow silts, sands and larger diameter particles to pass. Image: High clearance diagram Another advantage of air-powered automatic pumps is the long term durability provided by the relatively low-speed, high clearance nature of the moving parts. With air-powered automatic pump systems, air tubes are run to the pump instead of electricity, which provides immediate benefits in simplicity and safety. Pumps are delivered as a complete system, with all the necessary tubing, connectors and custom wellhead flange or cap closures. The units light weight and compact size speeds installation and generally requires only one person. Service is easy due to mechanical simplicity, light weight and ease of handling. Controls Air-powered automatic pumps require minimal controls because level control is built in via the float-operated on/off mechanism inside the pump. Image: Wellhead Air-powered pumps have a unique advantage in their ability to throttle back flow to meet changing site needs. First, stop/start cycle limitations do not apply to these pumps, so no adjustments need be made if well recovery rates decrease substantially from the original project estimates; the air-powered pump will function as intended, at a reduced refill/discharge cycle rate. If pump output rate reduction is desired, several options are available. The discharge flow may be throttled back, the applied air pressure can be easily adjusted downward with the provided regulator, or the pump's vent tube may be throttled back. Finally, without electrical power or components, there is no expense added to deal with explosive conditions, shock hazard, or lightning damage prevention. Emulsification of Free-Phase Liquids Air-powered automatic pumps do not cause significant emulsification of free-phase hydrocarbons, if these are present, due to low speed operation, without the shearing action of impellers. Less emulsification helps the performance of any downstream oil-water separators. Diameter Air-powered automatic pumps are available in diameters to fit 2-, 3- and 4-inch wells. In general, the larger diameter models are better able to handle solids, due to the greater clearances within the pump. Materials Manufacturers offer a wide range of materials of construction to meet site-specific conditions. Some of these materials include stainless steel, acetal, nylon, Teflon, brass, epoxy, fiberglass and UHMW. These material choices allow higher operating temperatures for air-powered pumps, compared to electric submersibles. For example, many steam-enhanced recovery projects have successfully used air-powered pumps for years. Solids Air-powered automatic pumps are especially well-suited to handle the solids that can be encountered, especially in landfill leachate. This solids handling advantage is derived from these pumps' large internal clearances, low speed components and especially the air-on-fluid driving force.  Wear due to pumping solids is minimal, and should it ever occur it is easily serviced by field replacement of the intake valve seat. In the event that the air-powered automatic pump does get filled with silt, it simply stalls without damage, and can be flushed out and returned to service. On/Off Cycling Flow/Pressure Output Without an internal motor to overheat, air-powered automatic pumps are not affected by on/off cycling or the need to operate on a limited flow/discharge head curve. Any flow rate below the maximum is sustainable indefinitely, and full discharge head is available even at low flows, so air-powered automatic pump systems are less affected by discharge line restrictions or variations in flow. Temperature Landfills and heat-enhanced remediation systems often have elevated liquid temperatures which can exceed the limits of the motors in electric submersible pumps. Without a downwell motor, air-powered automatic pumps are not subject to overheating. The pump model must be selected for materials appropriate to the temperature. Air-powered automatic pumps have been successfully used on many high temperature projects, and are warranty covered for such applications as long as the appropriate pump model has been selected. Summary of Air-Powered Pump Strengths and Weaknesses Strengths Long-term system reliability and durability in applications with difficult fluids and solids System materials, dimensions and inlet can be configured for site-specific needs Not affected by frequent start/stop cycles as flow needs decline Complete systems available from one source Safety and simplicity of air-power vs. electric Very little emulsification of hydrocarbon mixtures System simplicity - no control box needed, level control built-in Weaknesses Not capable of higher flow rates of electric submersible pumps Less energy efficient than electric pumps Higher priced than general duty water supply pumps Drive air contact with pumped liquid can be a source of fouling deposits at some sites  Case Studies Landfill Gas Well Dewatering Steam Enhanced Cresote Pumping Thermally Enhanced NAPL Recovery 2007 Outstanding Ground Water Project Reward Brown County Landfill Case Study Getting Started Converting Landfill Gas to Energy Puente Hills Landfill Case Study Tel (734) 995-2547 • Toll-Free in North America (800) 624-2026 • Fax (734) 995-1170 © 1982 - 2010, QED Environmental Systems, Inc.   All Rights Reserved.