Many companies pump aggressive liquids such as the chemical process industry, pharmaceutical manufacturers, electronics com-panies and even the food industry. A solid pump will keep these potentially dangerous liquids safely contained and prevent harm to employees and the environment.

In the food processing industry, a mixture of acids is sent through pumps in order to disinfect them before filling them up with a new ingredient. The electronics industry pumps chemicals used in the etching process for their circuit boards, and the car industry pumps paint and fuel solvents. All industries that handle liquids require a pump at some point in the industrial process.

These days, companies need bigger pumps than ever to meet increased demands on production and delivery. That is why pumps with a high capacity that are simple to use and inexpensive to maintain are a welcome addition on the market.

Tapflo recently developed the T800 air-powered diaphragm pump. This is a 3 in pressure-powered diaphragm pump with a pumping capacity of 820 litres per minute at an air pressure of 8 bar. It is the latest in the company’s range of air-operated double diaphragm pumps, and one of the largest pumps available on the market today. With a pump capacity double that of existing diaphragm pumps, it is designed to handle large flows, an uncommon advantage in this type of pump.

The T800 has a large connection point, which allows the through-flow of sharp and rough waste products of up to one inch, making it highly suitable for industries pumping abrasive particles, such as ceramics or metal.

Tapflo has used a keep-it-simple approach to constructing the pump, by using very few components. The T800 has fewer parts than traditional diaphragm pumps. This means less down time and lower maintenance costs compared to other such pumps, says Tapflo’s Export Director Håkan Ekstrand.

“We have re-defined the pumping principle by reducing the number of parts by 50 %. At the same time, the T800 requires 30 % less air consumption, cutting down on energy and pollution.”

Although it is more compact than other pumps of its kind, the T800 has all of the advantages of a large pump, without compromising on any features, including safety. “This is a high performing pump that is also available with explosion-proof execution,” Ekstrand says.

Diaphragm pumps are operated by compressed air and do not require lubricants or health hazardous oils. This is a clear advantage in environments where hygiene is required.

“The T800 can handle aggressive and corrosive chemicals without getting worn or corroding because there are no rotating parts. And since it is a diaphragm pump, there is no need for dynamic seals, which are a common cause of leakage and pump failure,” Ekstrand explains.

Features

The speed of the pump is controlled by an infinitely variable airflow control that offers flexibility and is easy to adjust. Because the pump is air driven, there is a lower risk of injury as with more complicated electrical pumps. It is also easy to install and to operate, and therefore requires no special training, which also keeps labour costs down.

This solid pump is built for long life and can run dry without getting damaged. “By increasing the size of the pump and opening up the ports, we’ve reduced the velocity through the pump, decreasing wear and tear on the pump’s interior and these factors result in a longer lasting pump,” Ekstrand says.

And if the pump is consistently operated below its specified performance, it will last for ages, he adds: “If you run this large pump at just over half of its specified performance, you can lengthen the lifetime of the pump even more. Do this and it will not fail you.”

Diaphragm pumps operate with compressed air. In Tapflo’s pumps, two diaphragms, connected by a shaft, are pushed back and forth by alternately pressurising the air chambers behind the diaphragms using an automatic air valve system.

One diaphragm creates a suction action when pulled back from the housing while the other diaphragm transmits the air pressure to the liquid in the housing, pushing it towards the discharge port.

During each cycle, the air pressure on the back of the discharging diaphragm is equal to the head pressure on the liquid side. These pumps can therefore be operated against a closed discharge valve with no adverse affect to the life of the diaphragms.

Material choice

The T800 pump is made of polyethylene (PE), which has a superior wear resistance that is six to seven times better than that of the more commonly used polypropylene (PP) material. Polyethylene is highly resistant to mechanical wear or abrasion, making it suitable for handling abrasive materials and aggressive chemicals such as concentrated acids and alkalis. Polyethylene pumps are also very hygienic – and practical for use with liquid temperatures of up to 70°C.

The T800 is also available in virgin polytetrafluorethylene (PTFE) plastic, and by the end of 2007, there will be aluminium and stainless steel versions as well.

In addition to having the same capabilities as a PE pump, PTFE pumps can also handle really aggressive acids, such as concentrated nitric acid. They can also handle liquid temperatures of up to 100°C.

The T800 aluminium pumps are mainly suitable for pumping fuels, paints, solvents, and other chemically neutral liquids.

A stainless steel version, which is easy to clean and polish, will help industries with high demands on hygiene, such as the food, cosmetics and pharmaceutical industries. The stainless steel version is also appropriate for high temperature chemicals and liquids.

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