Plunger "Combination scale" device structure. For powder, granular and viscous materials packaging. More suitable for small mobility, easy caking and bridging to produce phenomena such as plunger packaging materials. Mainly by the hopper, the housing, the plunger and the frame and other components. "" works as follows: the role of testimony linear reciprocating piston drive mechanism, when the plunger is moved to the left, turn the valve clockwise close the feed tube open feed tube, the materials are fed through a hopper feeding tube sucked plunger and the housing cavity formed realize metering; when the plunger is moved to the right turn valve counter-clockwise to open the closed tube feeding tube, the material is pushed into the discharge pipe falling into the bag, "" automatic blanking complete metering requirements.