Team 10, Catheter Wash System Jon Blyer, Jim Moore, Dan Muhlenforth, Gwen Thorson Advisor: Dr. James Glancey Sponsors: Deborah Grohol, Bill Gregory Preliminary Design Verification We were uncertain the submerged pressure washing system would work. This system was verified by designing a single catheter washer that utilizes the concept. The results of the cleaning method was evaluated with respect to Terumo’s standards. Problem • TERUMO® Medical Corporation, manufactures medical catheters for use in arteries and veins • These catheters must be cleaned to remove foreign matter and contaminants accumulated during the manufacturing process, before packaging • Current cleaning process, requires a trained operator • Benefits of a solution would be higher throughput, improved product quality and ergonomic improvements • After benchmarking we found no commercially available devices to perform all the required tasks. Wants/Constraints Chosen Concept Internal Wash External Wash Upper Manifold delivers AK-225 and air to inside of catheters through luer lock Lower Manifold delivers AK-225 and air to the outside of the catheters Solvent Delivery • Lure Lock Fittings ISO 594 to hold catheters • Inner surface rinsed for 5 sec with AK-225 • Outer surface cleaned with AK-225 • Operator Safety • AK-225 reclaimed and recirculated • Teflon tubing for transporting solvent • Solvent Level Indicators • Catheters undamaged (minimum bending) • Ease of Use/Speed of Use • Low Matianance, Automated Device • Low Cost • Small device footprint Actuator Pneumatic Cylinder moves the upper manifold for catheter installation and seals cleaning chamber A Pressure Pot delivers AK 225 and air to the manifolds Control System Metrics/ Target Values • Minimize the amount of defection of the catheter tip with respect to the luer lock fitting. In order to determine a maximum value for this, a catheter was held horizontal and the amount of natural deflection was determined to be 20 inches. A PLC controls the system of eight valves involved in AK 225 delivery and recovery, and includes several indicator lights • The primary goal of this process is to clean the catheter so that the final coating will stick properly; thus the target value is 100% of coating sticking Enclosure Solvent Recovery Stainless steel tubes enclose the length of the catheter during the cleaning process The Catch Tank is a pressure vessel that collects the AK-225 as it finishes cleaning and returns it to the start • Produce an ergonomic improvement for the operators by reducing repetitive motion • In order to have an economically viable solution the throughput must be greater then or equal to what can be produced by hand. • Minimize loss of the AK-225, solvent by reclaiming and recirculating it because it is very expensive. Machined Fixture with 104 cm Catheter Operational Procedures Pressure Vessel Preliminary Design Verification Methods/Results Method: Prior to cleaning, a thin layer of silicon is applied to the catheter surface. After cleaning, a coating is applied to the tip of the catheter. The coating will not stick to any silicon residue not removed by cleaning. Catheters are then dipped in a red dye that will stick to the coating. Therefore, non dyed spots (green spots) on the catheter are undesirable. Trial 1 A: Good Result From these tests it was determined that the cleaning method is viable. Further testing is necessary to determine best operating conditions n. Pressure n. Duration n. Air/Solvent Mixture 1. Load catheters into the designated lure lock positions when the “load” light is illuminated. 2. Close upper manifold via pneumatic cylinder until the “Closed” light is illuminated 3. Clasp the latches, pinching the upper and lower manifolds together Proof of Concept Prototype • Opening large enough so that maximum deflection is not reached 4. Press the “Start” button 5. The valves controlling the air into the Pressure Pot and the pressure relief in Catch Tank are energized (opened) Proposed Concepts Catheters Upper Manifold Catheters Lower Manifold Scrubbers Vertical Rotating Washer: catheters are rotated as scrubbers clamp and move the length of the catheters. Vertical Non-Rotating Washer: a pair of perpendicular scrubbers move the length of the catheters. Power Washer: a manifold of high pressure nozzles move the length of the catheters. Submerged Pressure Washer: catheters are placed in tubes and solvent flows past them. Trial 5: Bad Result • Repetitive motion of cleaning the lengths of the catheters by hand, is eliminated from this process 6. After 5 seconds, a valve is energized sending AK-225 to the upper and lower manifolds. Simultaneously, the valve which sends air to the lower manifold is energized producing a mixing effect on the exterior of the catheter. • Design verification shows that cleaning method will allow final coating to stick 7. After 15 seconds, the valve controlling the AK-225 is de-energized and the valve which sends air to the upper manifold is energized. • Solvent contained and recycled with minimal losses. 8. After 5 seconds, the valves delivering air to the manifolds and Pressure Pot are deenergized. Also the pressure relief valve in Catch Tank is de-energized. Simultaneously, the valves allowing air into the Catch Tank, the pressure relief valve on the Pressure Pot, and the valve allowing AK-225 to transfer from the Catch Tank to the Pressure Pot are energized. • Automated controls to adjust the cleaning process Front of Prototype • More consistent cleaning method for any operator 9. After 20 seconds, all the open valves are de-energized and “Finish” light is illuminated. • Less training necessary 10. The operator can now remove the latches and raise the pneumatic cylinder until the “Remove Catheter” light is illuminated. • Higher throughput overall 11. After every 50 washes, the “Check AK” light would be illuminated at this point 12. When this happens, the AK-225 fluid level is checked and add as needed. Press the “Reset” button and continue cleaning. Back of Prototype
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