Peristaltic Pump Troubleshooting, Preventative Maintenance and Repair
The peristaltic pump is a very important component to the proper operation of an autoanalyzer instrument. If it is not functioning properly it is possible to have problems with reproducibility, accuracy, and prematurely worn pump tubing. Signs of a peristaltic pump problem might be observed as poor peak shape, split peaks, tailing peaks, surging, and inconsistent flow. There are a few places that an operator can inspect to immediately determine if this could be the problem.
First make sure that the roller heads are not excessively worn. Over time the pump tubes can wear into the material itself and cause a poor peristaltic motion as the roller head moves against the pump tubes. It is important to replace the roller heads when they are notably or significantly worn. Roller heads used in the FSIII/IV pumps are susceptible to buildup of dirt or chemicals on the metal surface that need to be cleaned with a light solvent such as alcohol. In fact as part of an ongoing preventative maintenance schedule these should be cleaned regularly before any buildup occurs thus increasing the life of the pump. These can be repaired if the cogs are broken or the roller heads themselves are damaged. It is also a good idea to test the integrity and smoothness of the individual rollers themselves as they turn on their individual axis by gently spinning them with your fingers. The gaskets and cogs that attach to the motor shaft may be worn, broken or dirty.
You might as well check the RPM of the pump to insure that the proper rotation is occurring. Sometimes pump main boards or motors will go bad and produce a slow, fast, or intermittent rotation which will significantly effect the peak shape. Simply mark a point on the roller head and measure how many rotations occur per minute and verify with the manufacturer the proper rotation.
Next area to pay attention to on an Ismatec Peristaltic Pump is to be sure that the platens are not worn, excessively grooved, or broken. Both of these areas can affect peak shape because the sample and fluids are not moving evenly and consistently through the system as the roller heads press against the pump tubes. Replace if necessary. Also it is important to insure that the platens are clean of dirt and particle buildup since this can also affect the smooth and consistent motion of the peristaltic pump. Next check that the platens are not worn, excessively grooved, or broken. The last areas that are small but critical to successful peristaltic motion are the four piece platen holder as well as the micro adjustment lever on the platen. The holder must be intact with its platen securing tooth not broken or it will not hold down the platen properly. Finally, if the platen lever is not intact it may produce inconsistent flow patterns.
This whole process may take only a few minutes but I often see these issues solve intermittent or unknown problems that a lab has been attempting to resolve over a long period of time. Please feel free to contact me directly if you have any other questions about peristaltic pumps or pump tubes themselves.
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