Pump development strengthens the weakest link

Fluidic development engineers have been challenged to integrate high performance miniature diaphragm pumps, vacuum pumps and compressors that last as long as their entire systems.

Fluidic development engineers have been challenged to integrate high performance miniature diaphragm pumps, vacuum pumps and compressors that last as long as their entire systems.

Unfortunately, current air and liquid diaphragm pump, micro vacuum pump and miniature air compressor technologies have been restricted by elastomer properties and motor designs that cannot withstand the challenging operating requirements these new generation systems demand.

Several OEMs have cited that the miniature diaphragm pump was the weak link in their equipment.

The diaphragm pump or compressor typically was the first component to either fail or need service.

Their expected life was found to be relatively low, with most miniature diaphragm pumps lasting less than only 3000 hours in real world operation.

This was unacceptable to most system designers as their products needed to operate in demanding environments for significantly longer.

The cost to the OEMs to rebuild the miniature diaphragm pumps or replace them with new ones was significant.

The consequence of having dissatisfied customers because their product was plagued with downtime due to miniature diaphragm pump, micro air pump or miniature vacuum pump issues was even more costly.

Several OEMs challenged Hargraves to develop a reliable miniature diaphragm pump and micro air compressor to last 10,000 hours under their rigorous application conditions.

This was determined to be the length of time that their product would last.

In addition, they challenged Hargraves to advance its own product technology by packaging the required performance in a much smaller, compact envelope.

These system designers realised that incorporating a reliable, service-free, miniature diaphragm pump with exceptional performance would permit them to reduce their own costs and increase their product's marketability.

The Hargraves engineers were receptive to the challenge.

They investigated the different reasons that pumps failed and benchmarked the existing technologies and designs.

Their research found three common failure modes of micro diaphragm pumps, micro air compressors and miniature vacuum pumps.

In many applications, the pump diaphragm would prematurely fail.

The material would fatigue or eventually tear due to the number of cycles under high temperature and prolonged pressure loads.

The Hargraves team determined that standard EPDM (ethylene propylene rubber) used in the industry was a major limiting factor in the life of the pumps.

EPDM diaphragms typically could expect a life approximately 3000 hours.

This of course was unacceptable to their customers that were requiring life performance under demanding conditions to exceed 10,000 hours.

To eliminate premature diaphragm failures, the Hargraves engineers searched throughout the elastomer industry for a material that would endure these rigorous demands at extended life cycles.

They were repeatedly told by the so-called "industry experts" that it could not be done.

Undeterred, the Hargraves team took the initiative to develop a high performance diaphragm material.

This research project resulted in the development of an Advanced EPDM, or AEPDM, a proprietary material configuration that has been tested to last ten times longer than those used by other pump manufacturers.

The life of the Hargraves' AEPDM diaphragms can exceed 20,000 hours depending on the application.

Diaphragm pumps have typically been powered with brush DC motors.

Due to the physical contact between the brushes and their commutator, the motor brushes eventually wear affecting its performance and life.

Brush motors are designed to last from only 500 hours to 6000 hours depending on the quality of the motor and how it is used.

Hargraves utilises a proprietary brushless DC motor that is smaller and lighter than that of the competitors.

Being a brushless motor, the brushes are inherently removed as a wear item resulting in reliable operation up to 20,000 hours.

Because of the heavy mechanical loads experienced by the motor of a diaphragm pump, the motor bearings were found to prematurely wear.

Proprietary bearing cage design, assembly methods, and materials were employed to reduce radial loading and promote long bearing life.

The result of this dedicated effort culminated in the design and development of the revolutionary BTC Series.

By employing Hargraves' intellectual properties, the state-of-the-art BTC pump enabled Hargraves' customers to achieve the following advantages over existing industry miniature diaphragm pump, micro air pump and compressor, and miniature vacuum pump technology: the pumps provide superior performance in a smaller package while operating under prolonged high load; they withstand higher operating temperatures, exceeding the industry's standard; Hargraves pumps lead the race for longevity, setting the highest benchmark for repair-free life expectancy; and they can be optimised to match specified noise requirements.

But Hargraves didn't stop there.

Despite the overwhelming response from fluidic system developers, the Hargraves team did not rest on its laurels.

Employing a continuous product improvement process, they saw other opportunities to increase miniature diaphragm pump and compressor performance and efficiencies.

Other improvements to their pump technology include increased pump head efficiency by improving the pump chamber, eliminating leaks, and optimising the valve system.

With ongoing customer demand to reduce audible noise levels produced by pumps, new design models have been routinely tested to discover the effects related to the pump operating sound levels.

Hargraves' advancements in motor technology and valve designs indicated above have contributed to significantly reducing pump noise.

Leaks in pump heads have often been an issue in miniature style pumps, especially with liquid pumps.

To this end, Hargraves has developed new sealing methods for both the diaphragm and the gasket used to seal the joint between the chamber and head.

Termed Fluid-Blok, pressures in excess of 4bar have been achieved with absolutely no evidence of leaks.

The success of the BTC spawned new challenges from customers for other demanding applications.

The need for increased flow from a dual-headed version in series derived the BTC-II.

The BTC-IIS was developed to meet pump applications that required the ability to operate both pressure and vacuum with the same pump.

The CTS Series met the requirements for lower flow and pressure requirements but fitting in a much smaller envelope.

The LTC Series was developed for customers that demanded high efficiency and the elimination of leakage for their high performance liquid applications.

Hargraves' core strength has been a powerful ability to form relationships with their customers to solve their most challenging fluidic system problems.

The company has a proven track record in partnering with many of their OEM customers to eliminate the high cost of customer dissatisfaction, repair and replacement.

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