P17080: Heart Pump and Circulatory System

Customer Handoff & Final Project Documentation

Table of Contents

Final Design Output

The final design used a silicone ventricle with air as the driving force to push water through the system. The water passes through the check valve and into the arterial tank. The arterial tank is pressurized to model the body's blood vessels resisting the flow. Then the water passes through the turn valve. The turn valve changes the correctional area of the tubing. This causes a change in compliance of the modeled blood vessels. As the turn valve is closed the pressure in the arterial tank rises. After the turn valve, the water enters the venous tank which models pre-load in the system. The pre-load is the pressure of the blood coming from the lungs that fills the heart. Since this process is similar to pouring instead of forcing liquid into the heart, the tank is open to atmosphere. Pre-load pressure can be adjusted by changing the height of the plunger to vary the water head. Finally the water returns to the heart to begin the process again.

Controls in LabVIEW software can change the heart beat and duty cycle of the system. The heart beat sets a time for each sequence on then off of the solenoid which makes up one beat. The duty cycle controls how fast the solenoid fires to alternate between air and vacuum pressure supplied to the pump chamber.

Final Project Output

Video Description of Overall System


Test Results Summary

Engineering Requirements vs. Accomplishments

Comparison of Engineering Requirements to Accomplishments

Comparison of Engineering Requirements to Accomplishments

Detailed Testing Document

See Test Information Here: FinalTest

Risk and Problem Tracking

Updated Problem Tracking

Updated Problem Tracking

See Live Document Here: Problem Tracking

Imagine RIT

Imagine RIT

Imagine RIT

See Poster Here: Poster

Final Project Documentation

Manuals, Drawings, and Protocols

See Manuals Here: Manuals

See Additional Diagrams Here: Additional Diagrams

See Drawings Here: Drawings

See Build Instruction Here: Build

See Technical Paper Here: Paper

LabVIEW Code

See Live Document Here: Final LabVIEW

See LabVIEW User Manual Here: Manual

Bill of Materials

See Live Document Here: Final BOM

Future Recommendations

Overall, the new design demonstrates physiological parameters modeled after the human heart and circulatory system. Optimizing smaller components of the system would increase the longevity. The current valves satisfy the system needs however, they are bulky and aesthetically displeasing. They also use a hinge which can wear out or break over time. Ball and cage valve are simple to construct using clear PVC piping. The ball can be 3D printed in the Rochester Institute of Technology construct. These valves have no connected moving parts which decreases the wear from constant use of the valves.

The solenoid currently driving the airflow was taken from a scrapped machine used to control HVAC. This solenoid is not typically used at the high frequency that the system demands. Also, since it was previously used, the remaining lifespan of the device is undeterminable. It is recommended to replace the current solenoid with one that is unused and rated for frequencies of 1 to 3 Hz. It would also be desired that the solenoid can allow higher flow to the chamber. An increased flow rate allows the system to change chamber pressure more dynamically.

The current mold for ventricle fabrication is a two-part mold. When the silicone cures, it clings to the positive insert which can cause difficulty removing the ventricle and damage to the mold. Using a spray to keep the silicone from gripping the 3D printed surface could prevent this problem. Another option is to redesign the negative part of the mold so that it is two separate sections. The process of extracting the silicone would involve separating the two parts of the negative instead of pulling the positive out.

The current LabVIEW program produces pressure and flow outputs that were desired. The code has opportunities for optimization. Parameters such as stroke volume, compliance, and total peripheral resistance could be calculated using the current outputs within the LabVIEW program. The system’s manual controls are the turn valve, pressurizing the arterial tank, and moving the plunger of the venous tank. Purchasing additional motors and sensors could allow LabVIEW to control these actions from the front diagram. This would decrease the opportunity for human error during laboratory experiments.

Action Items for Gate Review

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