Patent ID: 6071097
Filing Date: 2000-06-06
Classification: F04B

Abstract:
A piston for use in a pneumatically-activated pump having a chamber, the piston comprising:a first grooved end section having a head, a channel circumferentially disposed about the piston, and a slot extending from the head to the channel; the channel having a first side, a second side, and a base portion therebetween, and sized to receive a movable sealing member therein;a stem section having a longitudinally disposed conduit on the periphery thereof, the conduit having a first end and a second end, the first end of the conduit being in a fluid-flowing relation with the channel; anda second end section;wherein when the sealing member is seated in and adjacent to the first side of the channel, the first end of the conduit is open to allow unrestricted fluid flow between the conduit and the channel, and when the sealing member is adjacent to the second side of the channel, the first end of the conduit is blocked by the sealing member to prevent fluid flow between the conduit and the channel.