Midsouth Aggregates Found a Submersible Pump That Delivered Reliability to the Operation’s Stone Washing Tower.
By Mark S. Kuhar
Across the southeastern United States many producers are working to provide a steady and reliable supply of stone aggregate for construction projects. Aggregates are increasingly being used in environmental applications as well. Aggregates are critical components of soil erosion–control programs and can be found in water purification systems and are used to reduce sulfur dioxide emissions from electric power plants.
Midsouth Aggregates (sister company to Midsouth Paving Inc. and formerly known as APAC Mid-South Inc.) was formed in 2007, from businesses supplying high quality aggregates, asphalt and construction services to the Alabama, Georgia and Tennessee marketplaces. Since 2009, Midsouth has also supplied the Florida Panhandle. Part of the Oldcastle Materials Group, the company is headquartered in Atlanta.
Oldcastle Materials Group annually produces 165 million tons of aggregates, 50 million tons of asphalt, and 10.5 million cu. yd. of ready mixed concrete at 1,400 locations nationwide. Oldcastle is the fourth largest aggregate producer in the United States and the largest producer of asphalt products.
Replacing a Pump
Shane Horton, plant manager for Midsouth Aggregates’ Alexander City, Ala., quarry operation needed to replace a submersible pump that pumped quarry water to a stone washing tower. He also wanted to increase the discharge flow of the pump.
The existing pump had a 4-in. discharge. The new pumping conditions were 1,000 gpm, 50 ft. of vertical lift and 500 ft. of horizontal run to the water tower. The manufacturer of the existing pump would have to use a pump with an 8-in. discharge in order to meet the new conditions; BJM could accomplish the job with a 6-in. KZN.
Scott Morrow, sales engineer for Brownlee-Morrow – a dynamic fluids transfer distributor specializing in pumping equipment, suggested a BJM Pumps submersible built specifically for hard to handle rock slurries.
Fulfilling Washing Requirements
Midsouth Aggregates didn’t have any experience with BJM submersibles, so Morrow provided information on the BJM KZN hard metal slurry pump. Specifically, Scott suggested the BJM KZN220 – 30-hp high head, hard metal agitator slurry pump.
Because of BJM’s wide experience in pumping coal slurries, line slurries and a variety of abrasive products found in wash down sumps, Midsouth Aggregates decided to give the pump a try. The quality features built into BJM’s KZN slurry pump series were also factors in the decision and include the following:
- Optimum Wear Resistance. All wetted parts are constructed of abrasive resistant 28 percent chrome iron (600 Brinell, 71 Rockwell C) for maximum wear life. In addition, a replaceable hardened wear plate is located on the suction side, where erosion would cause a loss of pump performance.
- Maximum Solids Handling Capability. An integral agitator fluidizes settled solids into a slurry making them easier to pump with less chance of clogging. The semi-open impeller handles abrasive solid concentrations as high as 70 percent by weight.
Also weighing into the decision was the fact that the KZN slurry pump achieves maximum service life because of numerous design features such as:
- Class H motor insulation and built in amperage (FLA) and temperature overload protection.
- Double silicon carbide mechanical seals in a separate oil filled seal chamber.
- Heavy duty lip seal that provides additional protection for the mechanical seals.
- Stainless steel shaft and shaft sleeve that provide maximum wear and corrosion protection.
- Pump volutes cast from hardened ductile iron (300 Brinell hardness), which is twice as abrasive resistant as standard ductile iron with walls that are extra thick at the point where pumped slurry enters the discharge.
|Left to Right: Kelly McCollum, BJM Pumps – Southern Regional sales manager; Richard Smith, Midsouth Aggregates; Shane Horton, Midsouth Aggregates – Alex City plant manager; and Scott Morrow, sales engineer for Brownlee-Morrow.|
Another key part of the pump construction is the semi-open impeller. Also made of 28 percent chrome, the slurry impeller must have the ability to work in tandem with the agitator to pass the aggregate through the pump and out the discharge. The agitator’s ability to keep solids suspended in the fluid being pumped, as well keep the suction clear of clogs greatly aids the pumping action.
Additionally, Midsouth Aggregates liked the BJM vertical top discharge feature of the KZN220 agitator pump. The existing submersible pump in Midsouth Aggregates’ application was a side discharge 90-degree elbow pipe that had a high wear area on the 90 degree turn.
BJM’s vertically positioned top discharge KZN promotes optimum wear resistance along the discharge path as well as use of the fluid being pumped for natural cooling of the pump’s internal motor functions. BJM’s vertical design also allows for the sump to be pumped down to within inches of the bottom.
Further, the vertical discharge and the 22.75-in. diameter of the KZN220 creates a space saving footprint and allows installation in the tightest of manholes.
Based on the high volume and harsh conditions of their Alexander City quarry operation, Midsouth Aggregates was seeking a submersible pump that delivered reliability to the operation’s stone washing tower. Brownlee-Morrow recommended and supplied a BJM KZN220 submersible pump that delivered what Midsouth Aggregates was looking for.
Information for this article courtesy of Mike Bjorkman, vice president of BJM Corp., who has more than 30 years of experience in the pump industry. He serves as director of marketing and IT for BJM Pumps LLC and All Test Pro LLC. Both companies are subsidiaries of BJM Corp. He can be reached at 860-399-5937.