Utilizing proven spiral groove technology, the Type 28VL harnesses the rotational energy of the pump shaft to vaporize the process fluid at a controlled rate, creating a stable gas film that lubricates the seal faces. Typical problems, such as dry-running wear, vapor lock in the seal chamber and "face popping" (which can lead to catastrophic failure of conventional wet seals), are eliminated by the Type 28VL non-contacting face technology.