The Problem: A company was developing an innovative syringe to add nutrients and pesticides to trees as an alternative to harmful chemical spraying. The syringe leaked when operated and even when it was stored in the trunk of a car. Having seen Apple Rubber product literature, the company gave us a call.
The Solution: We helped to completely revise the design of the syringe.
Finding the cause of the leak –To use the syringe, a hole is drilled into the base of the tree and the chemicals are injected. The plastic syringe featured an O-ring between the plunger and the fluid cavity. The pressure created by the plunger pushed out the wall of the fluid cavity and caused the syringe to leak. Also, in higher temperatures, the plastic tended to expand, causing even more leakage.
Working with plastic to design the solution –We discovered that the cavity wall and the O-ring were too thin. Initially, we prescribed a thicker O-ring made of 50 durometer Buna N which would stand up to the pressure. Then, relying on an in-depth knowledge of plastics, we took it a step further and redesigned the entire unit, doubling the wall thickness and reconfiguring the O-ring groove to better accept the seal.
A better solution and a better product –We provided the solution and delivered more than 400 prototype seals in a matter of days. Not only did we deliver a better sealing solution, our knowledge of plastics also helped the company design a better, more efficient syringe.