AODD PUMPS FOR CHEMICAL PROCESSES

Advancements in efficiency and a good array of chemicals combine to form the air-operated double-diaphragm (AODD) pump a useful choice for chemical processors.

The circumstances surrounding the event of the air-operated double-diaphragm (AODD) pumping principle six decades ago involved a ruptured hookah, a flooded workshop and an exclamation that the thought could “make 1,000,000 dollars.” within the ensuing 60-plus years, those words have proven to be prophetic, because the AODD pump technology that was said to be “conceived out necessarily, born within the arms of innovation, and inspired by sheer will and determination” has become a frequent choice for operators in heavy-duty industries that need the pumping of water, slurries or any finely divided substance, like cement.

AODD pumps (Figure 1) can obtain dry self-prime, run dry, maintain suction lift up to 30 ft, withstand deadhead pumping conditions, operate while completely submerged and pass solids of up to three in. in diameter. However, in some ways since their invention, AODD pumps became pigeonholed by many pumps users, who see them as only usable in utilitarian, auxiliary or basic liquid-handling and transfer applications.

In reality, because of a series of noteworthy refinements that have economized the AODD pump’s method of operation, the unit can now be considered a real “process” pump and has gained acceptance intrinsically within the diverse sectors of the chemical change industries (CPI), including paints and coatings, ceramics, adhesives and sealants, foods, beverages, pharmaceuticals and cosmetics.

THE AIR IN THERE

Despite the very fact that AODD pumps have proven their effectiveness in utilitarian liquid-transfer applications, there has always been one annoying glitch in their operation: at the top of each pump stroke, a small, but still significant, amount of air was wasted. This kept the pump from operating most efficiently and added to its bottom-line cost of operation.

Because of that, AODD pump manufacturers in Africa must find methods to decrease or eliminate the air loss at the top of the pump stroke. This led to a series of advancements within the technology behind air distribution systems that have enabled the AODD pump to optimize air usage while still maintaining its operational characteristics.

While air loss has been a continuing concern within the operational window of AODD pumps, the earliest air distribution systems were designed first and foremost to battle another operational irregularity within the AODD pump’s performance: stalling and icing. It had been just one occasion those performance inhibitors were conquered that designers turned their attention to developing ways to more efficiently govern the pump’s air consumption.

One of the primary air-distribution systems designed to market energy efficiency featured a dial that would be wont to tune the pump’s operating speed by restricting the quantity of air that was allowed to enter the pump. It’s a fact of AODD pump life that a slower-running pump is more efficient. For instance, a dial-in air distribution system running at full throttle may consume 50 std. ft3 /min of air so as to pump 100 gal/min of fluid. Using the dial, the incoming compressed gas are often dialed back to a 35-std. ft3 /min rate, where the pump will transfer the liquid at a flowrate of 80 gal/min. this is often a 20% reduction in flowrate, amid a 30% reduction in air consumption, which makes the pump more efficient.

While the dial-in air-distribution system represented an undoubted advance of diaphragm pump Africa in operation, there was still more field that needed to be plowed if pump performance was to succeed in true levels of optimized air consumption. A newer technology for air-distribution systems features an air-control spool (Figure 2), which is formed, more or less, like an hourglass. This development was driven by an evaluation of the pressure dynamics that occur within the AODD pump during its operation.

This evaluation clearly revealed that air consumption was significantly impacted by a rise in atmospheric pressure at the top of every diaphragm stroke. Specifically, when the shaft would come to a period at the top of every stroke, a shift signal would be sent to point that the flow of air should cease. However, there was a little delay between the stopping of the shaft and therefore the sending of the signal, meaning that the complete force of the compressor continued to push compressed gas into the air chamber, but that air wasn't doing any actual work and was lost to the atmosphere upon exhaust.

AODD Pump manufacturer and supplier in Africa, Antlia Works specializes in manufacturing and supplying AODD Pumps as per industrial requirement.