When choosing a centrifuge, the user should fully consider the factors such as the use occasion of the centrifuge, the use temperature, and the characteristics of the material in order to achieve the intended use effect. The following aspects should be considered during selection:
1. Anti-corrosion performance: The materials separated by the centrifuge are generally corrosive, and the materials in contact with the materials must meet the requirements of corrosion resistance to ensure the safe use of the centrifuge.
(1) The types of structural materials are: Q235.A, Q345.B, SUS304, SUS321, SUS316, SUS316L, titanium, Hastelloy, etc.
(2) Surface treatment methods include: plastic lining, rubber lining, PTFE lining, surface spraying Halar and so on.
(3) Filter cloth (net) materials include: canvas, polyester, polypropylene, imported composite polypropylene, sintered mesh, etc.
(4) Sealing materials are: rubber, fluororubber, tetrafluoro, etc. The user informs us of the properties of the material (physical properties, chemical properties, temperature during separation, etc.) when selecting the type, so that we can put forward the selection of the centrifuge according to the characteristics of the separated medium and specify it in the order.
2. Explosion-proof performance: In the material (or environment) processed by the centrifuge, if it contains flammable and explosive materials such as organic solvents and static sparks, the centrifuge should have explosion-proof performance. The explosion-proof performance is determined according to the explosion-proof requirements (grades) of the process.
(1) Mechanical system: explosion-proof motor, explosion-proof lighting, anti-static transmission belt, anti-collision measures;
(2) Electric control system: explosion-proof operation box, explosion-proof isolation barrier, non-contact energy-consuming brake, static grounding;
(3) Attachments: nitrogen protection devices, oxygen content detectors, etc. For places with explosion-proof requirements, users should state the separated medium, explosion-proof requirements and grades when ordering, so that we can configure corresponding devices and take appropriate measures to meet Explosion-proof requirements.
3. Separation performance: It includes separation effect, washing effect, processing capacity, degree of automation, etc. When ordering and selecting, it is difficult to accurately determine the final separation effect because of the differences in material properties, mainly including the viscosity, particle size and distribution, density, and solid-liquid ratio of the material.
(1) Separation factor is an important factor affecting the separation effect of a centrifuge. It refers to the ratio of the centrifugal force to the gravity of the material to be separated under the action of the centrifugal force field, which is related to the speed and diameter of the centrifuge drum.
Ft = ω2r / g where: ω is the drum angular velocity, and the unit is: rad / s
r is the drum radius, the unit is m
g is the acceleration of gravity, the unit is: m / s 2
(2) For some materials, the filter cake needs to be washed, and some even need to be washed multiple times to meet the requirements, which requires the configuration of a washing tube. The washing effect has a lot to do with the washing time, the rotation speed during washing, and the structure of the washing tube.
(3) The processing capacity of the centrifuge is related to the physical and chemical properties and separation requirements of the material, and is generally estimated based on the number of cycles of one hour and the weight of the cake produced by a single operation.
Dangerous factors that users may bring in the process of selection, installation, use and maintenance:
1. Improper selection, such as improper selection of model and specifications. As a result, the machine cannot be used normally, or the intended purpose is not achieved;
2. Use the centrifuge outside the specified range of use. For example, general-purpose centrifuges are used for flammable and explosive occasions; centrifuges without anti-corrosion measures are used to handle highly corrosive materials; 1Crl8Ni9Ti materials (materials in contact with material parts) are used for halogen-containing elements;
3． Not in accordance with the prescribed operating procedures. For example, the drum rotates in the reverse direction, overload operation, overspeed operation, etc .;
4． Do not install, debug, use, maintain the centrifuge or modify the parts of the centrifuge and add auxiliary devices by itself according to the requirements of the product instruction manual;
5． Operation and maintenance personnel do not conduct induction training;
6. Failure to remove faults and scrap the centrifuges in a timely manner, the rubber-lined and plastic-lined centrifuges are not checked frequently, and the hidden dangers (such as cracks, shedding, etc.) are not found in time to cause the failure of the drums and other accidents. Therefore, users should formulate corresponding measures during the selection, installation, use and maintenance to avoid dangerous factors in order to achieve the purpose of safe use.