frugal engineering of a Sterile docking device
2022
This was my senior design project for my undergraduate degree. We were tasked with creating a drastically cheaper Sterile Docking Device to be used in underprivileged blood banks in Kenya.
Sterile Docking Devices are used to divide donor's blood bags into smaller quantities, as that much blood is typically not needed at one time. In the Kenyan blood bank, they had no way of sterile transfer or resealing which resulted in them needing to throw out the unused blood.
My team of five was successfully able to create a single-use device for $2.67 per unit. This project won us first place in the Product Realization category of the Spring 2022 Design Expo at the University of Pittsburgh.
Check out the video!
Design Iterations
In an attempt to keep costs as low as possible, we initially tried to have the entire device made of plastic alone. We iterated through different potential cut-outs to best slice through the IV-tubing, but ultimately found that a small blade would need to be attached to effectively and consistently cut through the tubing.
The same conclusion was reached in regards to the sealing between the tubing and the entrance to the device, as the original plastic screws were highly prone to leaking. Thus, the plastic screws were replaced with rubber grommets.
Latch for lid to body
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Wall cavity for grommet insertion
Cavity for excess tubing
Indent for blade adhesion
Channel for liquid flow
To the left is a cross section through the middle of the fully assembled device. During manufacturing, the plastic parts would be injected molded with polypropylene. This would consist of the lid, base, and blade housing. Rubber grommets would be inserted into the wall cavities of each side of the base. Blades would then be glued into the indents on each side of the housing. The device would then be ready for use.
To use the device, IV tubing is inserted into the holes on either side of the base. The blade housing is then firmly pushed down to cut through the tubing. The lid is latched into place and the blade housing is rotated 90 degrees, aligning the middle channel with the tubing holes for liquid to flow through the device. The excess tubing that was cut off collects into the cavities seen in the diagram above, which is entirely isolated from the middle liquid channel to ensure sterility.
Although the single-use solution is not environmentally sustainable, our group opted to prioritize the low-cost and sterility of the device in order to increase access to this much-needed medical device for underpriviliged blood banks to cut down the amount of blood waste occurring without it.
Poster used for the Spring 2022 Design Expo for the school of engineering at the University of Pittsburgh where we won first place for our category.