Patent ID: 8864748
Filing Date: 2014-10-21
Classification: A61M

Abstract:
1. A reduced pressure treatment apparatus comprising: a piston chamber having a closed end; a piston disposed within the piston chamber and being movable between an extended position and a compressed position; a charging chamber disposed between the piston and the closed end, the charging chamber having a first volume when the piston is in the compressed position and a second volume when the piston is in the extended position, the first volume being less than the second volume; a biasing member between the piston and the closed end and adapted to bias the piston toward the extended position; a valve member allowing fluid to exit the charging chamber as the piston moves toward the compressed position and preventing fluid from entering the charging chamber as the piston moves toward the extended position; a regulated chamber fluidly coupled to an outlet port adapted for coupling to a delivery conduit; a passage between the regulated chamber and the charging chamber; and a regulator member to regulate fluid communication through the passage between the charging chamber and the regulated chamber; wherein the charging chamber stores a first pressure that is less than an ambient pressure; wherein the regulated chamber stores a second pressure that is less than the ambient pressure, the first pressure being less than the second pressure; and wherein the regulator member comprises a valve body and a regulator spring engaged with the valve body to bias the valve body against a differential between the ambient pressure and the second pressure.