Get pumped

Incorrectly applied pumps lead directly to higher maintenance and energy costs, greater CO2 emissions and shorter life cycles. New materials, designs, and technologies allow pumps to operate more efficiently, effectively, and reliably, and for a wider range of applications.

Energy savings: Energy consumption weighs heavily in the total cost of owning a pump. New technology that increases the efficiency of air-operated double-diaphragm (AODD) pumps could prove particularly beneficial in energy-intensive applications. Warren Rupp’s Sandpiper EST (energy-saving technology) pumps have an On-Board PowerGen system that runs completely on compressed air.

The EST program modulates air flow to optimize energy usage, while automated controls self-adapt to changing process conditions. As a result, it reduces air consumption, maintains flow, increases overall air capacity, and reduces energy use. Sandpiper EST pumps reportedly perform from 26% to 51% better than four competitive brands in flow-per-unit of compressed air. The EST technology is currently available on Sandpiper 2-in. and 3-in. standard-duty metallic pumps.

Certified green: A new variable-speed pump controller that reduces both energy and water consumption might qualify users for green incentives or rebates, and contribute to LEED certification. ITT’s Bell & Gossett Technologic 502 variable-speed pump controller, which controls four pumps in parallel, is designed to reduce electric and water utility costs and reduce equipment wear in HVAC and pressure-boosting applications.

The integrated pump controller and adjustable-frequency drive, combined in a single enclosure, uses customized algorithms to support a complete range of pumping applications. The Technologic 502 is expandable, allowing three follower drives of equal size to be added as needed. Alternation of multiple pumps is in both manual and automatic modes to provide even wear, and lag pumps will start automatically if the lead pump fails. The system supports local and remote start and contains four analog sensor inputs. It protects against motor overload, out-of-range operation, high-pressure conditions, insufficient suction pressure, thermal build-up in pressure-boosting applications, and accidental data loss.

Chemical resistance: Corrosive fluids and harsh environments wreak havoc on susceptible chemical pumps. A new unit that combines the chemical resistance of perfluoroalkoxy (Teflon-PFA) linings and the strength and corrosion resistance of stainless steel housings was designed to handle these conditions safely and effectively.

With Liquiflo’s Poly-Guard Series gear pumps, corrosive liquids such as acids, caustics, and inorganic salts never come in contact with metal. The PFA lining is mechanically bonded to the internal stainless steel surface. Other internal components are available in Teflon, silicon carbide, PEEK, Kynar PVDF, TTZ and other non-metallic materials. Poly-Guard’s sealless magnetic-drive design prevents fluids from leaking and chemicals from escaping. The pump is suited to high-purity services because its wetted parts are non-metallic, and to metering and transfer applications because of its smooth, pulseless flow.

Expanded stability: Diaphragms made of Teflon AF (amorphous fluoropolymers) enable microfluidic pumps and valves to operate stably in a wider range of temperatures than their silicone-rubber counterparts, according to researchers at the University of California, Berkley, for NASA’s Jet Propulsion Laboratory.

Pumps and valves with diaphragms made of silicone rubber, or PDMS, are designed to be stable from 5ºC to 80ºC (41ºF to 176ºF). Because the somewhat porous PDMS membranes retain water, and the formation of ice crystals exacerbates porosity, applications below 0ºC are particularly unsuitable. By comparison, pumps and valves with Teflon AF pneumatically-actuated diaphragms demonstrate stability from -125ºC to 120ºC (-193ºF to 248ºF). In addition to greater thermal stability, the polymer material is less permeable and more resistant to chemical attack.

Micro scale: Researchers at Caltech for NASA’s Jet Propulsion Laboratory developed a technique for making miniature scroll pumps. The proposed pumps would serve as roughing (low-vacuum) pumps for miniature scientific instruments such as portable mass spectrometers and gas analyzers.

The pump’s design and fabrication would differ from the conventional machining used for older, large scroll pumps. Instead, these would be micro-fabricated using the German LIGA method, which roughly translates as lithography, electroforming, and molding. LIGA provides the required tolerances at large aspect ratios. The pumps would contain two scrolls; one on a stationary baseplate and the other on a flexure stage. The circular orbit of the flexure stage would produce the pumping effect.

E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].