Double-channel equant pipette

The utility model discloses a double-channel equant pipette which comprises a shell, the bottom of the shell is sleeved with a suction pipe, a limiting rod is sleeved with the suction pipe, limiting blocks are bolted to the two sides of the inner wall of the suction pipe, the surface of the limiting rod is sleeved with a piston sleeve, and the surface of the limiting rod is sleeved with a first spring; through the arrangement of the shell, the suction pipe, the limiting rod, the limiting block, the piston sleeve, the first spring, the barrel body, the fixing rod, the piston, the second spring,the limiting disc, the valve body, the valve element, the connecting rod, the knob and the connecting pipe, the problems that the liquid suction range and the liquid discharge range of an existing pipette are both fixed; according to the pipette, the problems that mother liquor is easily polluted and the concentration is not uniform when the pipette is used in the same measuring range and repeated liquid absorption and d