Magnetic stirrers are suitable for liquids or solid-liquid mixtures that are not very viscous. They can be stirred alone or heated and stirred at the same time. It uses the continuous circular motion of a magnetic stirrer placed in the liquid in a rotating magnetic field to achieve the purpose of stirring the liquid. It has been widely used in laboratories of various universities, environmental protection, scientific research and health, epidemic prevention, petroleum, metallurgy, chemical industry, medical and other industries.
There are many factors that affect the working state of the stirrer, and we can only list some of the more important ones here. for example:
1) The shape of the stirrer. Generally speaking, the smaller the contact area between the stirrer and the bottom of the container, the better, because the friction between the stirrer and the container is small, but the balance of the stirrer itself is required to be high; the larger the contact area, the better the stability, so the two should be considered in balance.
2) The relationship between the amount of solution and the length of the stirrer. Use a small stirrer for small volumes and a large stirrer for large volumes.
3) The shape of the bottom of the container. The round-bottomed container has a converging effect on the small stirrer, which makes its rotational stability better; since the flat-bottomed container does not have this effect, the small stirrer is prone to revolve while rotating.
4) Whether the bottom surface of the flat-bottomed container is flat. Obviously, the uneven bottom surface will lead to the occurrence of revolution phenomenon.
5) Internal structure design of magnetic stirrer. The common design is to place a magnet of appropriate size under the disk surface, which is good for the uniformity of the magnetic field on the entire disk surface, and the rotation stability of the longer stirrer is good. We also noticed that some domestic magnetic stirrers use two small magnet balls that are very close to each other, so that the limited magnetic field is completely concentrated in the center of the working plate, so it is more suitable for small stirrers to run stably, but the size is too large. will not function properly.
6) The influence of high temperature conditions on the stirrer. The commonly used stir bars will gradually demagnetize under high temperature conditions, so after a period of use, it is necessary to confirm whether they still have sufficient magnetic properties.
By simulating the experimental conditions to compare the working states of stirring bars of different specifications, it is found that the stirring effect of Dalong magnetic stirrer is very comparable to that of a foreign brand.
