Overpressure hood

thingiverse

The approach is a cost-effective, quickly reproducible protective device that utilizes conventional materials. It's intended for medical personnel in high-risk areas where standard protective gear isn't available. It's still a prototype, and any suggestions for improvement are welcome! This overpressure hood requires only a few 3D-printed parts and can be manufactured from conventional PP/PE foil with a plastic sealing device. The PP material is more transparent but stiffer, while PE is easier to process and already comes in tube form. Both materials can be disinfected with alcohol. The function is relatively simple: clean compressed air is typically available in intensive care units. This air is introduced into the neck cuff via a pressure reducer at a flow rate of approximately 12 liters per minute. Fresh air reaches the hood's interior through printed inlets, while spent air is discharged via an outlet valve on top. As a result, the wearer is constantly supplied with fresh air. The hood is sealed to the outside via the neck cuff, thanks to overpressure inside. Even if there's a leak, no aerosols can enter the interior. Manufacturing: Used were PP tubes with diameters of 40 cm and 15 cm. With a bit more sealing work, it's also possible to use conventional foil. The hood is first manufactured inside out. A 85 cm long PP tube with a diameter of 35cm (outer cover with chest and back protection) was cut off, removing the upper corners with an edge length of 12 cm. The lower 30 cm of the tube on both sides was then cut, creating the breast and back protector. An 85 cm long PP tube with a diameter of 15 cm (neck cuff) was also cut off, with the printed inner parts inserted into the tube (see illustrations). The tube was folded twice and sealed at 40 cm. The resulting neck cuff was slid over the outer cover so that it was positioned above the 30 cm incisions. A strip of newspaper was placed inside the tube to keep the hood open during sealing. The neck cuff and outer cover were then sealed from both sides. Next, the top side opening was sealed. The newspaper strip was removed, and any excess plastic foil was cut off. From the inside, the printed inner parts of the air inlets were clipped into place. These inlets should be located on the left and right. The foil over the air inlets was cut open with scissors, leaving one hole each for a flow rate of 12 liters per minute. The number of openings needed to be tested with the intended air supply. More holes would result in lower cuff pressure. The hood was then turned over (neck cuff on the inside). An opening for the tube connection was cut with scissors, and the tube connection was pushed through and fixed with an outer plate. Some glue may be necessary on the outside. Finally, the air outlet valve was clipped over the foil (plate inside), creating a foil membrane by cutting the foil at the outer edge in a quarter circle over 0.5 to 1 cm. Depending on the air flow, this opening can also be made on the opposing side.