Solved and Sealed

Getting to the Root of It

A company set out to develop an innovative syringe for adding nutrients and pesticides to trees as a more environmentally-friendly alternative to harmful chemical spraying. One small problem – the syringe leaked both when operated and when it was stored in the trunk of a car.

After seeing Apple Rubber literature, they gave us a call.


No Leaf Left Unturned

The syringe worked by drilling a hole into the base of a tree, through which chemicals were injected. The plastic syringe featured an o-ring situated between the plunger and the fluid cavity.

The pressure created by the plunger pushed against the walls of the fluid cavity and caused the syringe to leak. And, in higher temperatures, the plastic tended to expand, also causing leakage.

We soon discovered that the cavity wall and the o-ring were too thin. Our team initially recommended using a thicker o-ring made of 50 durometer Buna N which would better 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.


Our team was able to provide a solution and deliver more than 400 prototype seals in just a matter of days. Not only did we deliver a better sealing solution, but our knowledge of plastics also helped the company design a better, more efficient syringe.