Pipette automatic production line manufacturers know that graduated pipettes are glass measuring tools commonly used in laboratories, and rich scales can be used to pipette special volumes of liquids. According to the distribution design and usage method of the scale, it can be divided into three categories.

　　The first type of tube has the zero scale at the top, and the maximum scale is above the tip of the bottom. The pipes of all scales are of the same thickness. When using, first suck the liquid to the top 0 scale, and then drain the liquid to the target scale. Set the meniscus twice. Later, people wondered whether it is possible to only set a concave liquid surface once, and how many rows can be sucked? Under this idea, the second-type tube was born.

　　The second type of tube has the maximum range at the top, and the 0 scale is at the nozzle at the bottom. When in use, the liquid is sucked up to the target scale, and then the liquid is completely discharged. It only needs to set the concave liquid level once. In this way, one step of meniscus setting is saved, and the design from the scale to the nozzle also saves more reagents. However, the problem of fully draining the liquid is that the volume of residual liquid at the nozzle is different each time, especially when the nozzle is not cleaned thoroughly, which has a great impact on the accuracy.

　　For the three types of tubes, the zero scale is at the top and the maximum scale is at the nozzle at the bottom. When in use, first suck the liquid to the top 0 scale, and then discharge the liquid to the target scale. It is necessary to set the concave liquid level twice. The third type of tube is actually an improved type of the first type of tube. It adopts the solution of saving liquid from the scale of the second type of tube to the nozzle. question.

　　So at present, Class II tubes and Class III tubes are the mainstream products. For those who require high precision and are proficient in the operation of the concave liquid surface, use three-type tubes; for those that require high efficiency and can guarantee the cleaning effect, use two-type tubes. And now there are pipette controllers, both manual and electric, which can be controlled with one hand, and the meniscus is easier to control, faster and labor-saving.

　　If there is a higher requirement for efficiency, a bottle-top dispenser can be used, which has the same accuracy but higher efficiency and is safer.