A eccentric roundel structure for four-booster-chamber diaphragm pump comprises a motor with an output shaft, a motor upper chassis, a wobble plate with integral protruding cam-lobed shaft, an eccentric roundel mount, a pump head body, a diaphragm membrane, four pumping pistons, a piston valvular assembly and a pump head cover, wherein said motor upper chassis includes a bearing to be run through by the output shaft of the motor, and an upper annular rib ring with several fastening bores evenly disposed inner and outer circumferential rim thereof;
- said wobble plate with integral protruding cam-lobed shaft includes a shaft coupling hole for being run through by the corresponding motor output shaft of the motor;
- said eccentric roundel mount includes a central bearing securely fitted at the bottom base thereof for engaging with the corresponding wobble plate with integral protruding cam-lobed shaft, four truncated-cylinder eccentric roundels evenly disposed on the bottom base thereof in circumferential location such that each truncated-cylinder eccentric roundel characteristically has a horizontal top face, a truncated cylinder peripheral, a female-threaded bore and an annular positioning dent formed on the top face thereof respectively in horizontal flush, as well as a sloped top rim downwardly slanted from the annular positioning dent towards the joint of the horizontal top face and truncated cylinder peripheral;
- said pump head body, which covers on the upper annular rib ring of the motor upper chassis to encompass the wobble plate with integral protruding cam-lobed shaft and eccentric roundel mount therein, includes four operating holes disposed therein in circumferential location evenly such that each operating hole has inner diameter slightly bigger than outer diameter of the truncated-cylinder eccentric roundel in the eccentric roundel mount for receiving each corresponding truncated-cylinder eccentric roundel respectively, a lower annular flange formed thereunder for mating with corresponding upper annular rib ring of the motor upper chassis, several fastening bores disposed thereat in circumferential location evenly;
- said diaphragm membrane, which is extrude-molded by semi-rigid elastic material and to be placed on the pump head body, includes a pair of parallel outer raised brim and inner raised brim as well as four evenly spaced radial raised partition ribs such that each end of radial raised partition rib connects with the inner raised brim, four equivalent piston acting zones are formed and partitioned by the radial raised partition ribs, wherein each piston acting zone has an acting zone hole created therein in correspondence with each female-threaded bore in the truncated-cylinder eccentric roundel of the eccentric roundel mount respectively, and an annular positioning protrusion for each acting zone hole is formed at the bottom side of the diaphragm membrane;
- each said pumping piston, which is respectively disposed in each corresponding piston acting zones of the diaphragm membrane, has a tiered hole run through thereof, after having each annular positioning protrusion in the diaphragm membrane inserted into each corresponding annular positioning dent in the truncated-cylinder eccentric roundel of the eccentric roundel mount, by running fastening screw through the tiered hole of each pumping piston and the acting zone hole of each corresponding piston acting zone in the diaphragm membrane, the diaphragm membrane and four pumping pistons can be securely screwed into each female-threaded bore of corresponding four truncated-cylinder eccentric roundels in the eccentric roundel mount;
- said piston valvular assembly, which suitably covers on the diaphragm membrane, includes a downward outlet raised brim to insert an indented brim formed between the outer raised brim and inner raised brim in the diaphragm membrane, a central dish-shaped round outlet mount having a central positioning bore with four equivalent sectors such that each sector contains a group of multiple evenly circum-located outlet ports, a T-shaped plastic anti-backflow valve with a central positioning shank, and four circumjacent inlet mounts such that each inlet mount includes a group of multiple evenly circum-located inlet ports and an inverted central piston disk respectively;
- and said pump head cover, which covers on the pump head body to encompass the piston valvular assembly, four pumping pistons and diaphragm membrane therein, includes a water inlet orifice, a water outlet orifice, and several internal and external fastening bores while a tiered rim and an annular rib ring are disposed in the bottom inside thereof so that the outer brim of the pump head cover after assembling of diaphragm membrane and piston valvular assembly can hermetically attach on the tiered rim.