The Problem: Previous installation of vertical line shaft and dry pit pump design. The station was becoming increasingly expensive to maintain and operate. Adding to maintenance issues were the pump station’s age and location—it had been operating for more than 30 years within a floodplain. The station was flooding several times a year, requiring costly repairs and loss of use of the station
The Solution: In 2010 the county commissioner approved a replacement project of the old station. Design specifications called for the new pump station to handle a peak flow capacity of 60 MGD; in order to reduce or eliminate station flooding, improve efficiency, and assure reliable operation.
To meet those objectives, design architects determined the need for minimum of 30” suction and 24” discharge, that motor horsepower could not exceed 350HP, that the station be equipped with a variable frequency drive system, and that the system have the ability to function should the new station flood. The pump selected needed to have a capacity of 20 MGD at approximately 75 feet Total Dynamic Head (TDH).
Submersible type, non-clog sewage pumps were evaluated versus vertical non-clog sewage pumps with immersible motors. The Cornell immersible design of four (4) Cornell Immersible Pumps, model 20NHF-VC20, operating at 720 RPM, 350 Hp, with Continental Immersible Motors offered premium efficiency when compared with pump systems from other manufacturers.
End Results: The four (4) Cornell 20NHF-VC20 pumps with Continental Immersible Motors have been operating since late 2010. The station was put to the test in the first couple months of operation—heavy spring rains forced the station to maximum capacity. It performed above design standards, reaching and maintaining 76 MGD—26 percent above design requirements.
Saves more than $30,000 annually through new installation efficiency and productive increases
A large California construction company boasting more than 5000 employees had a seepage problem. As one of the top ten producers of both aggregate and sand/gravel products, the company wanted to extract aggregate from around a gravel pit that frequently filled with water, in large part because the pit sits atop an underground river.
To combat the water, the company had installed another manufacturer’s pump on barges to dewater the pit and transfer the water out of the area. However, these vertical pumps were not performing to expectations. More water than was acceptable was filling the pit—making extraction less effective, and therefore more expensive. The problem was exacerbated when the company dug for new material; they got closer to the underground river and increased the seepage rate.
The area Cornell distributor had a solution: barge-mount several pumps at 45 degree angles to maintain efficiencies and minimize suction lift. The barges and a four foot by three foot strainer basket with a solid steel top to prevent vortex were designed in concert with Cornell Pump engineering. The pumps also had to be more efficient, given the high cost of electricity in this area of California.
Two Cornell 12NHTB-F18DB pumps utilizing grease lubed bearing frames drive the new design. Cornell NHTB pumps were chosen because of their superior solids handling characteristics. Through the increased efficiencies of the pumps, the aggregate company saves more than $10,000 per pump annually, plus additional tens of thousands of dollars per year in increase production from not extracting materials under higher water conditions.
Canadian Mining and Power Operator Utilizes Hydraulic Submersible Pumps in Unique Applications
Cornell’s Hydraulic Submersible 6NNT Pumps Put to the Test—and Deliver!
Abrasive slurry, temperature swings of more than 100 degrees Fahrenheit, remote locations…any of these things would test a pump system. A Canadian mining and power company faced all three obstacles to transfer solids out of waste ponds.
In one application, the company created a Hydraulic Tiller Dredge utilizing a Cornell hydraulic submersible 6NNT pump married with a CAT engine to remove bitumen from a retention pond. The pump package sits atop a six-foot long Caterpillar Landscape tiller. The tiller is lowered to the bottom of the pond and feeds constant slurry into the pump. The highly abrasive slurry is 50 percent harsh bitumen solids by weight, coursing through the pump at 2,000 gallons per minute.
The same company found another inventive use for a Cornell 6NNT and a Caterpillar tiller in a similarly challenging application. In order to pump sludge out of ponds, the package the company created had to be able to rapidly change locations, change pump depths, and tackle thick particulates. They ingeniously placed the hydraulic submersible pump on the end of a John Deere 410 excavator, replacing the Deere’s bucket with the pump and tiller. The excavator’s hydraulic system powers the pump. The pump is submerged in the sludge, and then the excavator boom moves the pump around like an egg beater to dredge out the pond.
Cornell pumps durability, reliability, and easy maintenance are keys to operating in the tough conditions and challenging environment. Cornell offers 10 versions of our submersible pump from three inch to 12 inch sizes.
In 2011 a local mining operation in the Pacific Northwest approached a Cornell Distributor for a solution to recurring pump failure/maintenance issues. The mine had been using a leading manufacturer’s self-priming trash pump to move light slurry, with a specific gravity of 1.1, from a collection area to a silt clarifier.
With a design flow requirement of 1100 GPM @ 75’ TDH (which included a 12’ suction lift), the existing pump chosen was running 1500+ RPM (belt driven) requiring a 50-HP motor when the consistency reached the optimum 1.1 specific gravity.
Originally, the pump wouldn’t run longer than 45 days before failure, so it had been converted to the manufacturer’s suggested wear resistant material. Even with this change, the mine might expect only 120 days of operation before the pump was completely worn out.
Inefficient operation, continuous belt maintenance, and priming related issues, in addition to continuing pump failures, led them to spend nearly $35,000 annually on this one system alone.
The Cornell REDI-PRIME® 6NHTA offered them the opportunity to install a guaranteed priming system that would pass the solids and slurry independent of the pump operation (no continuous recirculation through the volute), run at a speed 20 percent lower than the existing pump, be direct driven (no belts required) and increase the pump efficiency from 58 to 75 percent, thereby greatly reducing the power consumption.
The REDI-PRIME® pump recently surpassed the one year anniversary of commissioning date and so far the pump has not been pulled from service or required any maintenance attention since installation.
Testing indicates the pump is still operating at optimum efficiency. The deferred maintenance costs have more than paid for the project installations costs and the estimated power savings of 6.7kw/hr is producing another $3,500.00 in annual savings.
Cornell 16NHG22 Redi-Prime® Pumps Move 2.6 Billion Gallons of Water in Seven Weeks.
Diamonds are among the most expensive items by volume in the world. Finding where they are is usually difficult; extracting them can be even more difficult. In the far Canadian North, a diamond consortium was investigating promising geological formations for diamond deposits. They were stunned when their exploration turned up three columns of diamonds, with an estimated yield of more than 130 million carats weight.
The diamond columns were located about 12 meters (36 feet) underneath Lac de Gras in the Northern Territories. To retrieve the diamonds, the consortium planned to build dike walls around the column of diamonds, and pump out the water entrapped behind the dike. It would be a colossal task under any circumstance, but to keep to a mining schedule, and remove the water during the short Arctic summer, the former lake bed around the mine would have to be dewatered in seven weeks.
To move 2.6 billion gallons of water from the mine area and back into the lake, a fleet of eight Cornell 16NHG22 Redi-Prime® pumps were employed on two barges. Pumping more than 36,800 gallons per minute around the clock for 49 days, the pumps worked like champions, and did it in harsh conditions, operating just 125 miles south of the Arctic Circle.
Without the ability to successfully move that much water, that quickly, and without breakdown, the mine might have been delayed more than six months in its opening, costing the consortium tens of millions of dollars. Since 2003, more than 50 million carats of diamonds have been extracted. The mine is expected to be in operation past 2021, extracting high quality diamonds. Cornell pumps are expected to be used in the new underground phase of the mine, opening in 2013.
The new Cornell SP slurry series was tested in both the lab and the field. Cornell knew the pump was tough, surviving 1500 hours of lab testing, where the volute on the 4 inch Slurry Pump was polished and dented in more than 200 locations by a stream of 30 percent silica sand changed every 50 hours to keep the sand edges coarse. The amazing thing about that lab test was that the patented Cycloseal® mechanical seal still had primer from the original installation on it when the volute, impeller, and expeller all showed significant wear.
Another test of the slurry pump came from a pumping trial at a mining site. The 3 inch white iron slurry pump was moving heavy solids fed from a dredge head off a bottom of the pond. The pump worked continuously for three months without a breakdown, seal wear, or decrease in performance.
The pump was returned to Cornell to inspect. As with the pump in the test lab, the volute and impeller showed obvious signs of wear. Debris such as 3 inch long stick, numerous rocks, and metal band ends were pulled from the volute and piping of the pump. However, the Cycoseal® was still as pristine as when it went out of the factory. After three months of use in the harsh Canadian climate, it too still had the primer paint on the volute.
The president of the test company commented on the Cycloseal® system “It’s huge,” he said. “Not having to do a water flush or replace packing materials constantly saves time and money, and the Cornell pump performs runs like a top. Game changer can be overused…but in this case, Cycloseal® really does change the whole game for slurry pumping.”
Cycloseal® technology has been used on Cornell pumps in other industries for years, and the innovation is changing mine dewatering and slurry pumping. The Cycloseal® back plate removes solids and abrasive materials from the seal area while purging air and gas pockets, extending seal life and eliminating need for venting or water flush. Seals don’t leak and last up to three times as long as standard seals.
Cycloseal® is available on almost every pump Cornell produces.
Food Processing Company swaps out “unreliable, dangerous, and cumbersome,” electrical submersibles for Cornell 6ST.
While displaying Cornell pumps at the Sacramento Food processing show, The Cornell distributor for Central California was approached by the maintenance team from a well-known tomato processing facility in Stockton, California. This plant processes thousands of tons of tomatoes during the harvesting season and very rapidly turns them into various table favorites.
As part of the wash segment of processing the delicate fruit, a lot of waste is removed and washed away in what is known as a ‘trash wash.’ This waste has to be moved away from the now clean tomatoes and processed. The trash wash contain not only dirt, but also pieces of stems, bad peels, leaves, and so forth gleaned from good tomatoes, along with rotten or bruised fruit.
Because of the ripening time of tomatoes, the processing plant runs at capacity around the clock for approximately four months straight. Speed is needed to keep premium freshness at a maximum and waste at a minimum. The processing company had been employing large electric submersibles to clean out the giant wash trays in the trash wash section of the plant. They electrical submersibles were not performing well, even being described by the plant personnel as “Unreliable, dangerous and cumbersome.”
One of the main complaints was the inability to monitor the electrical submersibles while they were operational. If the pumps weren’t working efficiently, that wasn’t noticed until the trash wash backed up; delays there impeded the line and imperiled the maximum amount of tomatoes being processed. Ultimately those slowdowns made the plant less profitable than it could have been.
The distributor suggested a self-priming solution from Cornell. With these high quality self-priming pumps, the plant staff can maintain and clean their pumps safely and efficiently. They can tell if there is an issue immediately, and they have the confidence that issues are rare with Cornell. This has helped increase plant efficiency several percent—with millions of pounds of tomatoes that extra efficiency translates into more operating revenue for the plant.
The plant is so impressed with the pumps that they are working with Cornell and the distributor to find other pumps to replace with Cornell’s solids handling, high volume, and high head solutions.