Based in Brisbane, Australia, Ai Scientific has flourished to become a leading designer and manufacturer of liquid automation equipment. One of its most successful products is the AIM3300 autosampler, a device that helps the company's customers introduce automated sampling procedures into their respective analysers.
A critical component of the AIM3300 is its integral peristaltic wash pump, which has been supplied by Watson-Marlow since the product was introduced. Reflecting the success of the 400DM2 pump is the fact that Ai Scientific is now producing its third generation autosampler, having sold over 5000 models worldwide since production began.
There are two main reasons we use Watson-Marlow peristaltic pumps: reliability and cost, explains Ralph Donaldson of Ai Scientific. As the AIM3300 is an integral component of our customers' analysers, it must be reliable. It needs to be capable of processing large numbers of samples every day without failure.
If it breaks down, it reflects poorly on our customer's instrument reliability. So we in turn must use high quality and reliable components in our products that will suit the environment and demands placed on us by our customers.
The AIM3300 autosampler is designed to automatically transfer multiple liquid samples sequentially into a laboratory analyser and is used in a wide variety of different analytical techniques including: ICP spectroscopy; AA spectroscopy; TOC analysis; gel permeation chromatography; ion chromatography; trace mercury analysis; segmented flow analysis; and viscosity analysis.
While each of these techniques has their own idiosyncrasies, they all typically require sample volumes in the range of 0.5-100ml for analysis.
The Watson-Marlow 400DM2 pump is used by Ai Scientific as an in-built wash pump for the AIM3300. When the sample probe is directed to a wash station, the pump is activated by the software to transfer fresh wash solution to the wash station.
As many of the company's customers are using their analysers to measure chemical trace levels, cleaning the probe between samples is very important to eliminate any cross contamination between samples.
Peristaltic pumps have no valves, seals or glands, and the fluid contacts only the bore of the hose or tube thus eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump. Simple to install, easy to use and quick to maintain, they are the world's fastest-growing pump type.
Fluid is drawn into a pump and trapped between two rollers before being expelled. The complete closure of the hose gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running.
Over the years we have only had good experiences of using Watson-Marlow peristaltic pumps, says Mr Donaldson. Add that to the ability of Watson-Marlow to provide application assistance and it is a winning formula.
We have now developed a close working relationship to the point where Watson-Marlow work with our design engineers and sales team to determine which pump configuration (pumphead, gearbox, motor) will best suit our customer's application requirements.
The autosampler manufactured by Ai Scientific deploys a unique 'pirouette' motion for the sample probe instead of the more traditional linear XYZ movement, which offers three distinct advantages: the z-axis design, often the most complex directional component, is simplified and uses a theta axis rotation; the probe movement can be faster for the same point-to-point movement; and the design lends itself to a range of different models of varying sample capacity through the use of common component parts.