Agitator shaft: The power output from the motor in the mixing device is transmitted to the agitator through the agitator shaft, so the agitator shaft must have sufficient strength. At the same time, the agitator shaft must be connected to the agitator and through the shaft sealing device as well as bearings, couplings and other parts, so the agitator shaft should also have a reasonable structure, high machining accuracy and tolerance. According to the support situation, the agitator shaft can be divided into a cantilever type and a single span type. The cantilever type stirring shaft does not have an intermediate bearing or a bottom bearing inside the mixing device, so the maintenance and repair is convenient, especially the biological, food or medicine mixing equipment with high cleanliness requirements, and the components in the equipment are reduced, so it is preferred.
Internal components: including baffles, coils, guide tubes, gas distributors, and the like. In order to eliminate the swirling phenomenon of the liquid in the stirring container, the stirred liquid is tumbling up and down to achieve uniform mixing, and it is usually necessary to add a baffle in the stirring container. Usually, the width of the baffle is about 1/12~1/10 of the inner diameter of the container. The accessories in the device such as a thermometer, a heat transfer coil or various supports can also play a certain baffle function, but often do not reach Go to "full baffle condition". Generally, the number of baffles and their widths are increased, and the power consumption is also increased. However, after increasing to a certain value, the power consumption will not increase any more. The working condition at this time is called "full baffle condition". In the agitated vessel, the fluid can flow to the agitator in various directions, the length of the fluid varies, and the flow guide can be used to determine the flow rate and direction for determining the flow condition. The guide tube is a cylinder that is open at the top and bottom, and is installed in the container to guide the flow in the mixing and mixing, which can improve the agitation of the fluid in the container, strengthen the direct shearing action of the agitator on the fluid, and cause a certain cycle. The flow allows the fluid in the container to pass through the intensive mixing zone in the draft tube to improve mixing efficiency. After the guide tube is installed, the circulation path is defined, reducing the chance of fluid short circuit. The guide tube is mainly used for the diversion of propulsion, screw and turbine agitators.
Shaft seal: Shaft seal is an important part of the mixing equipment. The shaft seal is a dynamic seal. Its function is to ensure that the stirring equipment is in a certain positive pressure or vacuum state to prevent the material to be stirred and the infiltration of impurities. Therefore, not all shaft seal types can be used for the stirring equipment. In the mixing equipment, the most commonly used shaft seals are liquid seals, packing seals and mechanical seals.
Liquid seal: When the working pressure in the mixing device is normal pressure, the function of the shaft seal is only to prevent dust and impurities from entering the internal working medium, or to isolate the working medium from the environmental medium surrounding the stirring device, the liquid seal can be selected. The liquid seal has a simple structure and has no frictional parts in direct contact with the drive shaft. However, in order to ensure that the gap between the cylindrical housing or the stationary element and the rotating element meets the design requirements, the processing and installation requirements of the sealing part are high. At the same time, due to the structural characteristics, the use of liquid seals is narrow. Generally applicable to working medium is non-flammable and explosive or mild toxicity. The working pressure in the equipment is equal to atmospheric pressure, and the temperature range is 20-80 °C. It is worth noting that the liquid working medium should not be filled with the stirring equipment; and the sealing liquid should be used as much as possible in the working medium of the stirring equipment or the neutral liquid which does not have physical chemistry with the working medium, and must be volatilized little and does not pollute the atmosphere.
Packing seal: It is a shaft sealing structure adopted earlier by the mixing equipment. It has the advantages of simple structure, low manufacturing requirements and convenient maintenance. However, the filler is easy to wear and the sealing reliability is poor. Generally, it is only suitable for agitation equipment with normal pressure or low pressure low speed, non-corrosive and weak corrosive medium, and allows regular maintenance.
Mechanical seal: The mechanical seal is a device that changes the sealing surface of the rotating shaft from the axial direction to the radial direction, and the two end faces of the moving ring and the stationary ring are adhered to each other, and the relative movement is used to achieve the sealing, which is also called the end face sealing. The mechanical seal has low leakage rate, reliable sealing performance, low power consumption, long service life, no need for frequent maintenance, and can meet the automation of production process and high temperature, low temperature, high pressure, high vacuum, high speed and various flammable, explosive and corrosive. Sealing requirements for abrasive, abrasive media and media containing solid particles.