Definition
A laboratory electric mixer is a commonly used laboratory equipment that mixes, homogenizes, disperses, or promotes chemical reactions in liquid or solid-liquid mixtures by driving the mixing components by an electric motor. It is a general-purpose sample preparation and preparation tool widely used in many fields such as chemical industry, food, materials, environmental monitoring, and teaching and research.
Principle
The basic working principle of a laboratory electric mixer is based on a motor that converts electrical energy into mechanical energy. The motor output shaft drives the stirring paddle to rotate through the transmission structure, and the paddle generates shear force and eddy current on the medium during the rotation process, so as to achieve the purpose of mixing. The speed is usually adjustable by an electronic speed control system to accommodate different viscosity media and mixing requirements. The hydrodynamic behavior involved in the agitation process can be described in part by the Reynolds number (Re), which reflects the fluid flow state:
Re = ρND²/η
where ρ is the fluid density, N is the stirring speed, D is the diameter of the paddle, and η is the hydrodynamic viscosity. The size of the Reynolds number helps to determine whether the flow is in a laminar or turbulent state, which guides the selection of stirring parameters.
Measurement method
The evaluation of agitation often relies on indirect measurements and process observations. Common methods include: monitoring the dispersion uniformity of the mixture by vision or instrumentation; The viscosity change of the fluid before and after mixing was measured using a viscometer. Mixing efficiency is evaluated by sampling and analyzing changes in the concentration of the target component over time during processes involving mass transfer or reactions. The performance parameters of the mixer itself, such as rated speed range, output torque, power and operating stability, can be measured according to relevant electrical and mechanical standards under no-load and load conditions using tachymeters, torque sensors and other equipment.
Influencing factors
The stirring effect is affected by multiple factors. Equipment factors include: motor power and speed regulation range, the geometry and size of the stirring blade, and the material and rigidity of the shaft. The process parameters include: the set stirring speed and duration, the size and shape of the vessel, and the initial volume and viscosity of the material. Environmental conditions such as temperature can also indirectly affect the mixing process by changing the properties of the material. These factors need to be balanced comprehensively according to the specific application.
Applications
The application of laboratory electric mixers covers multiple industries. In the chemical field, it is used for the preparation and homogenization of samples such as coatings, inks, adhesives, etc. In food science, participate in the mixing process of simulating food systems such as beverages and sauces. The field of materials science is commonly used for the dispersion of nanomaterials or the preparation of precursor solutions. For environmental testing, it can be used for homogenizing water samples or soil suspensions for subsequent analysis. Its versatility makes it one of the regular configurations in basic laboratories.
Selection considerations
Choosing the right laboratory electric mixer requires systematic consideration based on actual needs. First, the physical characteristics of the sample to be processed, such as viscosity range, corrosiveness, or whether it contains particles, are related to the requirements for motor torque and corrosion resistance of the material. Secondly, according to the mixing intensity and accuracy required by the experiment, the necessary speed control method and range are determined. Thirdly, consider the adaptability of the mixing paddle to the vessel and whether it needs to be equipped with additional functions such as heating and vacuuming. Finally, the operating noise, safety protection measures and maintenance convenience of equipment are also aspects that need to be paid attention to in long-term use. It is recommended to refer to the performance and safety requirements of relevant industry standards or technical specifications, and make a decision based on actual trial experience.