Patent ID: 8641662

Claim:
A self-purging system for delivering a hydrogel composition formed by mixing first and second liquid components comprising, an applicator sized and configured to mix the first and second liquid components and form the hydrogel composition, the applicator including inlet paths that convey the first and second liquid components subject to a selectively applied application pressure P(A) into an outlet path for mixing and formation of the hydrogel composition for discharge from the outlet path, and a purge assembly comprising a source of liquid flushing agent subject to a substantially constantly applied purge pressure P(P) that is maintained at a magnitude that is less than P(A), and a purging path coupling the source to the outlet path to convey liquid flushing agent into the outlet path subject to the substantially constantly applied purge pressure P(P), the purge assembly further including a valve assembly communicating with the purging path and the outlet path being operable in response to localized pressure conditions in first and second flow conditions, the first flow condition permitting the flow and mixing of the first and second liquid components but not the liquid flushing agent in the outlet path during the application of P(A), for dispensing the hydrogel composition from the outlet path, the second flow condition permitting the flow of liquid flushing agent but not the first and second liquid components in the outlet path subject to the substantially constantly applied purge pressure P(P), for continuously flushing residual hydrogel composition from the outlet path, the valve assembly being automatically placed in the first flow condition in response to localized pressure conditions whenever P(A) is applied, the valve assembly being automatically placed in the second flow condition in response to localized pressure conditions during an interruption of the application of P(A).