What type of pump is desirable in an automatic sampler?

In the context of automatic samplers, a peristaltic pump is particularly desirable because it operates by moving fluids through flexible tubing using rollers that compress the tubing in a rhythmic manner. This method allows for precise control over flow rates and is less likely to introduce contamination into the sample, as the fluid only comes into contact with the tubing and not with the internal moving parts of the pump. This is crucial in applications where sample integrity is vital, such as in environmental testing and monitoring.

Furthermore, peristaltic pumps are capable of handling a wide range of liquid viscosities and can effectively manage both clear and particulate-laden fluids. Their design also allows for easy maintenance, as replacing the tubing is often the only requirement for upkeep. This makes them an excellent choice for automatic samplers that need reliability and ease of use in consistently gathering samples without compromising quality.

In contrast, diaphragm pumps, centrifugal pumps, and piston pumps have characteristics that may not be as well-suited for the specific requirements of an automatic sampler, such as maintaining sample purity and ensuring precise flow control.