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Patent 6527518---Elsevier Feature Article


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Patent 6527518---Elsevier Feature Article

  1. 1. feature new sump pump design Innovative pump solution to storm water backup The backup of storm water into basements and other underground building spaces during power outages of any duration presents costly problems for homeowners. To address this longstanding issue, US inventor Michael Ostrowski has designed and patented a new high- efficiency water-driven sump pump that utilizes the power available in the pressure and flow provided by the local municipal water utility. Here he discusses the market background and existing attempts to solve the problem before providing details of the new design and its performance. I AC pump solutions n the USA and many other These AC electric motor-driven countries, the practice of pumps are typically vertical providing perforated drainage For those fortunate to have houses on centrifugal designs, ranging from 0.25 piping at the footing of building hills or high ground, or for those with to 0.75 hp. Most are fully submersible, foundations has been commonplace municipal storm drains buried deep oil-filled designs installed entirely for nearly a century. Removing ground beneath streets, this drain-piped within the sump pit. Pedestal pumps water in this manner is essential for storm water discharges by gravity flow are also applied with more long-term foundation stability and to to lower ground or to city-provided conventional, air-cooled AC motors, minimize the potential for storm storm-water systems. For others on typically mounted 2-4 feet (0.7–1.3 water infiltration into below-ground flatter terrain and for those without m) above the sump cover and shaft basements, cellars and, more municipal storm sewers, AC electric connected to a vertical centrifugal importantly, finished living spaces motor-driven sump pumps are pump installed in the sump pit. As (Figure 1). Additionally, removing installed in a sump pit below the long as AC power is available, these this water prevents hydraulic pressure basement floor to eject this storm pumps provide a good solution, under the cement floor slab, water to a municipal storm drain or cycling on demand via an electrical Figure 1. Cellars and underground living preventing cracking and water over the top of the foundation and float switch. spaces are at risk permeation that otherwise will occur. away from the building. from infiltration by storm water. In the USA, homeowners experience power outages once or twice a year on average. Long-duration outages exceeding 1–2 hours occur on the average once every 2–3 years (Figure 2). In older communities, with mature trees in close proximity to overhead power lines, outages of both short and long duration can occur several times a year. Unfortunately, most of these outages occur during severe storms with high winds, lightening and heavy rains, often coinciding with high water flow rates to the sump pit. Power outages as short as 20 minutes or less can result in sump overflow. Power outages of longer duration, more than 1–2 hours or even days, can spell disaster for a homeowner, with thousands of gallons of storm water backing up from the sump and into the basement of the house, below- ground family room, garden apartment, or English basement. For 2 WORLD PUMPS October 2003 0262 1762/03 © 2003 Elsevier Ltd. All rights reserved
  2. 2. feature new sump pump design rental or portable generators, rental those with unfinished basements, driven generator with automatic start- AC or portable pumps and other often used for storage, work shops and up has been available for many years. make-shift approaches for removing play areas, the problem can be In addition to the generator itself, an backed-up storm water. nonetheless significant in terms of automatic transfer switch is needed to damage and clean up. For those with protect power utility workers from the More recently, additional factors have only AC-powered sump pumps and no risk of ‘back feed’ during outages, so come to the attention of many stand-by generator, any outage with that repairs can be safely made on insurance carriers and homeowners rainfall can result in significant storm their system. Due to the relatively alike such as the risk of moisture water backup. high installed cost of $5000–$15 000 damage and high humidity levels for a small generator set, fewer than Secondary DC throughout the building for long 1% of homes in the USA have such systems periods of time, the possibility of mould units. Although potentially promising contamination, health risk and the long term, fuel cells for homeowners long-term damage to the entire A partial remedy has emerged – the as a lower cost alternative to engine- dwelling. The worst case in some fitting of a second battery-powered driven generators are not expected in homes, especially in older DC motor driven sump pump. As long the near future. communities, is for storm-water systems as the battery remains well charged and raw sewage systems to be ‘cross- and in good condition, this additional What other possible energy sources connected’ either in the home itself or DC pump and battery is partially could solve this problem? Beyond via municipal systems overburdened effective for addressing the short battery DC pumps and generator sets, during heavy rains. The result for the duration outages. Actual hours of what other high reliability, unlimited homeowner during a power outage can operation for these DC pump and duration power sources could be used? be raw sewage backup through the battery packages are a function of Steam engines, engine-driven pumps? storm water sump or underground floor battery amp-hour capacity, pump Unfortunately cost, complexity, noise, drains. The human toll in terms of size/horsepower rating, motor and emissions, the need to auto start, and financial loss, damaged personal effects, centrifugal pump efficiency, the ‘duty safety remain as negatives as with difficult and often messy clean up, as cycle’, flow rate, and head of storm stand-by generators. Compressed air well as lost time, and the surprise nature water that must be ejected. As the DC cylinders? Unfortunately, such of the problem remains in the minds of motor operates and the battery compressed air storage would have to any homeowner who has experienced discharges, motor speed and/or torque be too large and costly overall. Solar, this problem. diminishes, reducing pump flow rate wind? Probably not available ‘24-7- and/or pressure performance, 365’. Thermoelectric/thermionic Stand-by generators eventually fully discharging with loss converters and sodium sulfur batteries of pump operation and storm water from the defence and aerospace backup. To protect the DC motor, The option for a stand-by, engine- industry – fine for spacecraft and most manufacturers of these battery DC pump systems provide an Figure 2. Power outages occur once or twice a year in the USA, mostly during heavy rain, lightening and high electronic cut-off control, opening winds. On average, outages exceeding 1-2 hours occur once every 2-3 years. the circuit to the DC motor before the battery is entirely discharged. So even for those with a battery-powered DC pump, storm water backup often occurs. According to major homeowner insurance companies in the USA, the cost of both covered and uncovered damages due to storm water backup is US$1.5-2 billion annually, despite the many battery DC pump secondary systems installed to date. In addition to the significant damage and monetary cost of storm water backup, below-ground flooding of homes and other buildings represents significant risk of injury or death for the people involved – from falls on wet surfaces, or electrocution as homeowners try to resolve power problems, operate WORLD PUMPS 3 October 2003
  3. 3. feature new sump pump design ocean buoys but, unfortunately, too hydraulic fluid, positive displacement lower pressure, to the sump itself, a costly and potentially dangerous for a actuators and pumps can approach sanitary sewer, or to discharge outside typical homeowner. nearly 100% efficiency in converting of the building. mechanical work/energy [force × Water-powered distance (F.dS) or torque × angle For the case of a 4” diameter actuator technology – high (T.dŁ)] into fluid energy [pressure × and the typical 30–50 psig water efficiency, simple change in volume (P.dV) or volume × supply pressure, a nominal 375–625 design change in pressure (V.dP)], and back lbf up/down force is transmitted to the again. Hydrostatic/hydraulic, positive lower 8” diameter piston, resulting in Hydroelectric power – the conversion displacement pumps with fluid power, 7.5–12.5 psig discharge pressure from of moving or falling water into shaft ‘hydraulic’ motor packages and the lower chambers with each stroke, horsepower via a water turbine to run incompressible hydraulic fluids can or approximately 17–29 feet (c. 5–9 a generator – traces back to da Vinci’s achieve very high system efficiencies m) of head – more than the 10–12 water wheel itself, converting the with good design practices. feet of head required in most momentum and energy of moving applications. With the 1:2 diameter water into shaft torque and To better understand the present ratio of the upper versus lower pistons horsepower. As with centrifugal invention, consider the workings of and their 1:4 relationship in areas, the pumps, hydro-turbine efficiencies hydraulic linear actuators and positive 5–6 gallon/min (c. 19-23 l/min) flow typically range between 40–60% with displacement, piston pumps, and that rate into the upper actuator results in losses due to fluid turbulence, water, like hydraulic oil, is a nearly a 20–24 gallon/min gross discharge momentum loss needed to change incompressible fluid. This new design flow rate from the lower pump fluid direction/velocity, and fluid is essentially a ‘double acting’ water- chamber, with the device operating friction at high velocities with driven linear actuator coupled with a with a 4” stroke and at approximately component surfaces. linear ‘double acting’ positive 23 strokes per minute. In the lower displacement piston pump, both with chamber, four check valves are fitted, During the past 50 years, the very high energy conversion and conventional 1.5” diameter piping to minimize pipe pressure drop hydraulics industry has developed efficiencies. and pipe friction losses. linear and rotary, positive- Principles of displacement actuators to provide operation Performance another means of converting fluid Figure 3. Concept power into mechanical work, but now for the piston with far better efficiencies. For As shown in the Figure 3, municipal For the case where the spent water from version of the incompressible fluids, such as water pressure and flow enter the the upper actuator is directed to the water-driven sump pump. upper actuator controlled by a sump itself, the net storm water flow valve that is designed so discharged is 15–19 gallons/min. In as to be either ‘full on’ or’ full most cases, full 20–24 gallon/min pump off’. The float itself is fitted performance will be possible, with the with adjustable stops to spent actuator water having sufficient provide for a finite on-off pressure remaining to be discharged duty cycle, as with the float directly out of the building in parallel switches found on con- with the ejected storm water or directed ventional AC motor sump to a separate sanitary sewer. pumps. On-demand, munici- pal water pressure and flow The efficiency of the design will be enter the self-reversing water 94–95%. With good design, O-ring supply valve, which directs and rod seal friction will be limited this flow and pressure stream to less than 20 lbf or approximately to alternate sides of the 4% of the 375–625 lbf connecting piston, reversing flow paths rod force. The only other area of automatically as pressure rises efficiency loss is in the ports of the in either of the chambers self-reversing water supply valve above and below the piston as fitted to the upper actuator. This the piston hits a stop at each efficiency loss will be limited to end of its stroke. The water 1–2%. High efficiency is an remaining in each chamber at important feature of the overall the end of each power stroke design, since the spent water is forced out of the actuator delivered to the upper actuator must on the alternate stroke, at ultimately be discharged from the 4 WORLD PUMPS October 2003 0262 1762/03 © 2003 Elsevier Ltd. All rights reserved
  4. 4. feature new sump pump design accommodated with a building along with the storm water diaphragm design for longer ejected by the lower piston and life and minimal or no chamber. Further, water venturi type maintenance. designs are commercially available but, due to their 40–50% efficiency, So when and where can I buy can consume more water than can be one? Watch future issues of ejected, often with rated gross or net World Pumps and your local discharges of less than 5 gallons/min, hardware store or plumbing falling far short of the 15–20 supply dealer for commercial gallons/min that is typically required. launch announcements. In Design variants the meantime, try to stay safe and dry when the lights go out! The design shown in Figure 1 and described above is merely one CONTACT example of the many bore sizes, flow Michael Ostrowski rates, stroke lengths and Inventor and President, strokes/minute of an entire family of Technology Market Consultants the many dimensional designs 707 Skokie Blvd., Suite 410 possible, with straightforward design Northbrook, IL 60062, USA. relationships determining component Tel: +1 847 205 9656 Fax: +1 847 498 5712 sizes, pressure and flow rates. For E-mail: larger homes, or commercial Figure 4. Diaphragm variant of the sump pump shown in Figure 3. buildings, the entire design can be scaled up in size, theoretically, without limit. For homes with shallow basements, the upper actuator can be smaller in diameter compared to the diameter of the lower pumping proposed chamber, to further minimize water consumption. As a stand-by pump operating only during power outages, water consumption and water cost are quarter page trivial compared to the avoided cost of flooding damage. The patent filings for this invention advert here (US Patent 6527518 and PCT 021/30284) include embodiments and claims for the fitting of diaphragms to either or both the upper actuator and lower pumping chamber, as shown in Figure 4. Notably, with diaphragms in the place of both pistons and their O- rings, the friction and efficiency loss noted previously is eliminated. Diaphragm flexing force will be less than 1 lbf for each diaphragm with this alternative design. Additionally, the cylindrical shape and finish quality on the inside surfaces of both cylinders become unnecessary, and either chamber can be shaped in similar fashion to conventional air- operated diaphragm pumps. Further, the storm water that must be handled may contain dirt, sand and other contaminants that are better RES No.419 – USE THE ENQUIRY SERVICE @ WORLD PUMPS 5 October 2003