Abstract: A front cover of a manual rotary pump includes a disk having a cavity eccentrically defined therein for airtightly receiving an oil seal. A through hole is defined in a bottom of the cavity to allow an input shaft of a rotor extending through the disk. The oil seal is airtightly sleeved on the input shaft for forming an airtight condition between the input shaft and the disk. The disk has at least two bores defined therein and longitudinally communicating with the cavity for operator to easily detach and replace the oil seal by using a tool extending through the at least two bores. A diameter of the through hole in the disk is slightly greater than that of the input shaft and the diameter difference between the through hole and the input shaft is ranged from 0.05 mm to 0.2 mm.

Abstract: A reciprocating pump includes a cylinder; a piston including apertures and an annular bottom flange; a first check valve secured to a piston rod and including an annular groove; a coupling at cylinder bottom; a sealing ring sandwiched between the cylinder bottom and the coupling; a second check valve engaged with the ring and including tunnels and a bottom socket; and a metal block fitted in the socket. Pushing a handle upward will move the piston rod downward to sealingly engage the flange with the groove, remove air from the cylinder, and block the coupling by both the socket and the block. Pushing the handle downward will move the piston rod upward to disengage the flange with the groove, open the second check valve, suck fluid into the cylinder through the coupling, the tunnels, and the apertures, and discharge the fluid.