Fermenter magnetic stirring has the advantages of good sealing, zero leakage, maintenance-free, good wear resistance, etc. The magnetic stirring system has upper magnetic drive stirring system and lower magnetic drive stirring system, which can cover 10L to 10000L fermenter, which is widely used in the fermentation stirring needs of biopharmaceutical field.

The magnetic stirring device is mainly composed of a driving motor, an inner magnetic sleeve connected with the motor, an isolation sleeve connected with the tank, an outer magnetic sleeve integrated with or connected with the stirring paddle, bearings, etc. The device relies on magnetic transmission and utilizes the principle of identical repulsion and opposite attraction between magnet materials to transmit the torque and rotational speed of the drive motor to the stirring paddle in a non-contact manner, thus driving the mixing of materials in the tank.

Structural design of magnetic stirring device

Isolation sleeve

The isolation sleeve of the stirring device is between the driven magnetic rotor and the active magnetic rotor. During the rotation of the magnetic rotor, the isolation sleeve is in an alternating magnetic field. According to Faraday's principle, the changing magnetic field will generate an electric field, thereby forming a current, and thus the eddy current will produce.

Rolling bearing

Through magnetic transmission, the reliance on mechanical seals in the mechanical transmission process is directly eliminated at the material level, effectively solving the problems of seal leakage and incomplete space isolation.

For positioning bearings, ceramic bearings (as shown in the figure) with extremely strong corrosion resistance and wear resistance are mainly used to achieve rotor positioning. At the same time, in the bearing installation space, a rotating flow channel is designed based on ASME-BPE cleaning requirements, relying on the flow of materials to form a lubricating film between the bearings to achieve the purpose of lubricating the bearings.

Stirring paddle

The core component in the stirring system that achieves stirring, mass transfer, and heat transfer is the paddle. The stirring paddle rotates to provide a suitable energy flow field for the materials in the tank to achieve mixing and contact purposes. At present, according to the mixing process, the basic forms of paddles can be mainly divided into turbine type (as shown in the figure), propeller type, anchor type, frame type, ribbon type, etc.

In order to effectively solve the hygiene problem in the field of biopharmaceuticals, reasonable process changes can be adopted to reduce or eliminate areas where materials may be hidden, and design verification, performance verification, operation verification and riboflavin testing can be performed before delivery. Regarding the traceability issue that the biopharmaceutical industry is concerned about, on the one hand, equipment manufacturing companies need to control quality from the source of materials; on the other hand, need to further integrate the stirring device and the tank in control, to achieve the connection between mixing and the reaction of materials, and further introduce the audit tracking mode to provide the necessary data support for traceability.