The invention relates to an
injector capable of realizing quantitative and fast suction. The
injector comprises a needle cylinder provided with a needle head and a
piston rod, wherein the end part of the
piston rod is provided with a
piston rod press
handle, a
retainer ring which is vertical to the needle cylinder and outwards extends is arranged around the needle cylinder, the
retainer ring surrounds the needle cylinder for a circle, the
piston rod press
handle is in a round shape by using the
piston rod as the circle center, an air bag is arranged between the
piston rod press
handle and the
retainer ring, each of the two ends of the air bag is fixed with the one opposite side of the piston rod press handle and the retainer ring, the air bag surrounds the periphery of the piston rod, and is provided with an air inlet
pipe and an air outlet
pipe which extend to the outside, a positive-installation reverse valve is arranged in the air inlet
pipe, an opposite-installation reverse valve is arranged in the air outlet pipe, the air inlet pipe only allows air to flow into the air bag, and the air outlet only allows the air to flow out of the air bag. The
injector has the advantages that the air is inflated into the air bag, the effect of pushing the piston rod to move is achieved, further, the effect of sucking liquid by the needle head is achieved, the
automatic control is realized, in addition, the suction speed is controlled through controlling the air inflating speed, the structure is light, ingenious and simple, and natural damage is avoided during storage.