Patent ID: 8419377

Claim:
A pumping device, comprising: a barrel; a top cover mounted on an open top of the barrel and connected to an ambient environment; a cylinder mounted in the barrel and connected to the top cover; a piston movably mounted in the cylinder; a plurality of check valves mounted on the piston to move in concert with the piston; an operation unit mounted on the top cover and connected with the piston to move the piston relative to the cylinder; a connecting unit mounted in the barrel and connected between the barrel and the cylinder; and a pressure adjusting unit connected between the barrel and the top cover, wherein the barrel has an inner portion provided with a receiving chamber; the top cover has a bottom provided with a shaft hole connected to the cylinder; the top cover has an inner portion provided with a release chamber connected to the shaft hole; the top cover has a top provided with a drain hole connected between the release chamber and the ambient environment; the top cover has a side provided with a connecting hole connected between the release chamber and the receiving chamber of the barrel; and the pressure adjusting unit includes: a pressure release piece movably mounted in the connecting hole of the top cover; a sealing gasket mounted on the pressure release piece and located between the release chamber and the connecting hole of the top cover to interrupt a connection between the release chamber and the connecting hole of the top cover; and an elastic member mounted on the pressure release piece and biased between the pressure release piece and the top cover to push the sealing gasket toward the connecting hole of the top cover.