Patent ID: 8419376
Filing Date: 2013-04-16
Classification: F04B

Abstract:
1. A pumping device, comprising: a barrel; a top cover mounted on a top of the barrel; a first switching valve mounted on the top cover to control connection between the barrel and the top cover; a base mounted on a bottom of the barrel; a second switching valve mounted on the base to control connection between the barrel and the base; a cylinder mounted in the barrel and connected between the top cover and the base; 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; and a conduit mounted in the barrel and connected between the barrel and the base, wherein the barrel has an inner portion provided with a receiving chamber; the top cover has an inner portion provided with a first flow channel and has a side provided with a shaft hole connected between the first flow channel and the cylinder; the first flow channel of the top cover has an upper portion provided with a first drain hole connected to an ambient environment through the top cover and has a lower portion provided with a first connecting hole connected between the first flow channel and the receiving chamber of the barrel; the first switching valve includes a first valve stem movably mounted in the first flow channel of the top cover; the first valve stem of the first switching valve has a peripheral wall provided with two first annular grooves connected to the first connecting hole and the first drain hole of the top cover respectively and has an inner portion provided with a first through hole connected between the first flow channel of the top cover and the first annular grooves; the base has an inner portion provided with a second flow channel connected to the cylinder; the second flow channel of the base has a lower portion provided with a second drain hole connected to the ambient environment through the base and has an upper portion provided with a second connecting hole connected between the second flow channel and the conduit; the second switching valve includes a second valve stem movably mounted in the second flow channel of the base; the second valve stem of the second switching valve has a peripheral wall provided with two second annular grooves connected to the second drain hole and the second connecting hole of the base respectively and has an inner portion provided with a second through hole connected between the second flow channel of the base and the second annular grooves; the cylinder has an inner portion provided with a piston chamber connected between the top cover and the base; the piston chamber of the cylinder has an upper end connected to the first flow channel of the top cover through the shaft hole and has a lower end connected to the second flow channel of the base; the conduit has an upper end connected to the receiving chamber of the barrel and a lower end connected to the second connecting hole of the base so that the second connecting hole of the base is connected to the receiving chamber of the barrel through the conduit.