As the basic equipment of the laboratory, the overhead stirrer looks simple, but there are still many precautions in actual use. Do you really know how to use it correctly? Let the editor take you through the details below.
Proper and disciplined operation can prolong the life of an overhead stirrer. Stainless steel stirring paddles are used to mix the salt solution. The salt solution contains chloride ions. If it is not cleaned in time after use, rust stains and corrosion will appear after a period of time.
Studies have shown that when the chloride ion content is greater than 25ppm, stress corrosion, pitting corrosion, and intergranular corrosion will occur in stainless steel. Therefore, in the experiment, we must pay attention to timely cleaning and maintenance in order to prolong the service life of the stainless steel stirring blade.
The overhead stirrer is a large-capacity mechanical stirring equipment, product features:
1. Stainless steel chuck, durable.
2. Digital display model, the speed and time can be roughly adjusted, and the working time can be fine-tuned in the working state.
The relationship between the stirring amount of the overhead stirrer and the viscosity: the stirring amount of the general stirrer is based on water. In practical applications, the samples will have different viscosity ranges. The viscosity increase and the stirring amount are not completely inversely proportional. The viscosity is increased by 10 times, and the stirring volume is reduced by 10 times for direct use.
Selection of stirring paddle: The shape of the stirring paddle directly affects the stirring effect. When the viscosity of the sample is relatively high, choose the anchor stirring paddle, which can continuously stir the sample near the container wall during stirring, so as to prevent the sample from sticking to the container wall and cannot be mixed. If the sample is easily suspended on the surface of the liquid, the descending type can be selected. If the sample is easy to precipitate, you can choose the ascending type to continuously stir the sample.
The overhead stirrer will calculate the output of the motor torque when the current changes when the load changes when the motor is running. But this torque is not proportional in any way to the viscosity of the sample. The overall output torque of the stirrer will increase with the increase of the viscosity of the sample, but there is no proportional relationship. Therefore, the torque display cannot be used as a viscometer. If you need to measure the viscosity of the sample, you need to equip a special viscosity measuring device.
If the sample is corrosive and the conventional stainless steel stirring paddle cannot meet the application, you can choose the stirring paddle with PTFE coating. However, the PTFE material is soft, so pay attention to the speed of use during use.
Remind everyone that when using the overhead stirrer, please check whether the random accessories are complete, then install the fixture in order, plug in the sensor probe for backup, put the required experimental solution in a beaker or flask, and put the stirring bar Put in the solution and place in the middle of the bottom tank.
