Application closeup: Extreme cleaning application for medical tubing


Products in medical devices have very critical cleaning and sanitation requirements prior to use with patients. Even something as simple as Teflon tubing has to go through a sophisticated cleaning process after being extruded. Arion Engineering has designed and built a system to etch tubing that will ultimately be used for catheter applications.

The cleaning process takes three steps:

  • The initial etching process uses a heated, super-saturated solution of metallic sodium dispersed in naphthalene. Since this is highly reactive with oxygen, the solution and this whole stage is kept under a nitrogen blanket to prevent any chemical degradation. The reservoir and treating trough is fabricated from stainless steel with an external jacket to circulate heated oil. This maintains the process at an even temperature throughout. A pump keeps the solution flowing from the reservoir to the trough while the newly extruded tubing passes through. Oxygen sensors monitor the nitrogen blanket constantly to ensure that there has been no loss of reactivity in the etchant.

  • The second stage is an alcohol wash that floods the tubing to neutralize any remaining sodium solution. The alcohol also circulates from a reservoir to keep a fresh supply on the product.

  • The third stage is a final hot water rinse to ensure the tubing is clean and there is no sodium or alcohol residue. The water circulates through a heated reservoir.

Since the operation is continuous, the cleaning solutions can be replenished while running as needed. One PLC controls and monitors the operation, collecting data from temperature, pressure, and oxygen transducers. This information feeds back to the machine operation and alarm circuits if any process variables move out of appropriate ranges. All motors and electrical connections are explosion resistant.

Control Engineering Daily Daily News Desk
Peter Welander
, process industries editor

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Sensor-to-cloud interoperability; PID and digital control efficiency; Alarm management system design; Automotive industry advances
Make Big Data and Industrial Internet of Things work for you, 2017 Engineers' Choice Finalists, Avoid control design pitfalls, Managing IIoT processes
Engineering Leaders Under 40; System integration improving packaging operation; Process sensing; PID velocity; Cybersecurity and functional safety
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Flexible offshore fire protection; Big Data's impact on operations; Bridging the skills gap; Identifying security risks
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
click me