Purdue MIND Vent

grabcad

Hi! We're a team mainly composed of students from the Purdue biomedical engineering club, along with two Clemson engineering students who also make up our team. ***Edit 1: Unfortunately, finals week has us rushing to get this model out, which is why several components are not properly aligned and lack proper joints. I forgot to include the transducers, but I do have their CAD files. Still working on revisions despite these busy times!***EDIT 2: There are a lot of files for models we created in-house as well as used from online resources. I'll try to upload individual files as I get more time or as requested, thanks for your patience.Our design draws inspiration from the 4-stroke engine concept, where we utilize a lead screw inside a piston. We believe this innovative approach can easily meet all the requirements needed for a ventilator due to numerous machine design adjustments.We designed our device around providing ventilation in an efficient way without using Ambu bags in order to achieve higher precision and adjustment. Our design consists of a flow setup as shown in images. The device will start its process by utilizing air and oxygen line hookups in the rooms attaching them to our device at two inlet valves. Next, the air to oxygen ratio will be controlled via a servo mixer. It's a very simple piece, just a standard servo creating blockage ratios in lines of air and oxygen. After the air and oxygen are put through the mixer, they enter the shaft of our device. The shaft is where our device design stands out because we utilize a design similar to a 4-stroke engine as shown in Figure 2. Our design consists of a shaft and piston controlled by a stepper motor. The inlet and outlets are controlled with simple CAMs as shown in Figure 3. First, we have a mixture of oxygen and air going into the main body of the shaft. The piston is lowered at this state to create negative pressure inside which helps pull in the mixture. Next, the inlet valve closes and the outlet valve opens, which leads to the patient. At the same time this valve opens, the piston pushes upward and forces all the gas out of the chamber at a certain velocity. This velocity can be varied by how forceful the stepper motor is when pushing out the air. The shaft itself can hold around 1L of air, and in order to adjust the tidal volume, the piston can be raised or lowered from its starting position, changing the air volume pushed through the outlet. Once the piston has fired and the exhaust valve is opened with a CAM simultaneously, the air goes through a check valve, through a heat & moisture exchanger (H.M.E.), and then into the patient. Upon exhalation, the exhaled air travels once again through a check valve and the H.M.E., thus providing constant heat/moisture for the next incoming breath. After passing through the H.M.E., a controlled valve is opened, allowing the exhaled air to finally pass through a filter before being expelled from the system.The main advantage of this design is that it can be adjusted to allow for individual patient care. Changing the starting position of the piston adjusts the tidal volume, changing the rate of the stepper motor varies the breathing rate, and changing its speed alters the number of breaths per minute a patient receives, thus allowing tuning for respiratory rate. We can easily adjust for Inspiratory:Expiratory ratios with the timing of the piston and a valve. We can readily modify the PEEP and PIP as well. All of these can be conveniently controlled via a simple microcontroller such as an Arduino Uno. The system has simple controls such that doctors can establish any setting they would like. Another advantage of using a simple microcontroller is that we can use several flow and pressure sensors, for these are very common to find, very affordable, and very simple to use. They will provide notifications of errors or failures in anything. Regarding our parts list, we are utilizing all very common parts and easy to print CAD parts. Our system uses very basic electronics built on a common platform Arduino, but can also utilize any laptop plugged in. Our motors are very common NEMA 17 stepper motors found in most industries. As for the valves, connectors, and the tubing, we are utilizing medical-grade bulk parts. The shaft and mechanisms are printable CAD parts created specifically for this system.