Diener Precision Pumps offers alternative to traditional syringe pumps
Fluid systems in medical devices are becoming compact and more sophisticated. The traditionally used syringe pumps seem no longer able to keep up with the new requirements in terms of size, cost and performance. Valve-less piston pumps that combine the benefits of syringe pumps with lower cost and higher performance, could be the solution.
Historically, syringe pumps have long been the mainstay in dispensing and metering applications because they can be accurately controlled and have very good dispense accuracy. An additional benefit is their inherent high pressure capability. On the down side, they are costly and bulky and require a long refill time.
Diener Precision Pumps, a Swiss manufacturer of gear and piston pumps, has developed an alternative solution for medical devices. John Bishop, director of sales and marketing at the company, says: 'Ceramic piston pumps, which support both rotary and linear movement and use longer displacements and higher speeds, meet all necessary requirements. The pump can fill quickly and still dispense with high accuracy, following a sinusoidal dispense/fill curve.'
By designing the pump's geometry, life-limiting check valves are eliminated. This increases pump life and reduces cost. Accuracy is maintained using very tight operating clearances, typically in the 2-3 micrometre range. In addition, ceramic is strong and can only be treated with diamonds. Ceramic pumps can therefore be used over the entire life-cycle of an appliance without losing precision and dispensing accuracy.
Later adjustments and maintenance services are not needed. Typically, the only wetted parts are alumina ceramic, PTFE, and a polypropylene seal material. The wear of the mating ceramics is undetectable after thousands of hours of operation, meaning that the pumps maintain their accuracy over time.
A variety of piston sizes and strokes, combined with adjustable displacement features built in to the pump head give the end user a great deal of design flexibility. The inherent design simplicity allows fewer parts and a wider selection of inert materials. Sensors can be included to monitor speed, temperature, and pressure/vacuum. Combining these features reduces initial costs and results in a very long life fluid delivery system.
