The total volume of the internal mixer-the volume of the cavity formed by the internal mixing chamber, side support (or retaining ring), discharge door, and mound minus the volume of the two rotors in the internal mixing chamber. It is the main parameter indicating the size of production capacity, and is generally adopted according to series standards.
　　 Working volume (rated volume, feeding volume) is the total volume of the internal mixer multiplied by the filling factor ψ. The filling factor is selected according to the rotor form, the type of rubber material, the process formula, the process parameters and the size of the mound pressure, generally 0.55 to 0.75.
　　The charging capacity is the mixing capacity. Insufficient capacity will reduce the shearing effect and kneading effect on the rubber, and even the rubber slip and the rotor idling, resulting in poor mixing effect. On the contrary, if the capacity is too large, it is difficult for the rubber to turn over, and the upper bolt position is improper, so that a part of the rubber stays at the neck of the feeding port, so that the rubber is not uniformly mixed, the mixing time is long, and the equipment is easily overloaded. High energy consumption. Therefore, the mixing capacity should be appropriate, usually 60% to 70% of the total effective volume of the closed chamber is appropriate.
The mixing capacity of the internal mixer can be calculated by the following empirical formula: Q——filling capacity, Kg; K——filling coefficient, usually 0.6～07; V——total effective volume of the closed chamber, L; ρ—— The density of the rubber compound, g/cm3. The selection and determination of the filling coefficient K should be determined according to the type and formula characteristics of the raw rubber, the characteristics of the equipment and the degree of wear, and the pressure of the upper bolt. For NR and formulations with high gum content, K should be appropriately increased; for synthetic rubber and formulations with low gum content, K should be appropriately reduced; for old equipment with a large degree of wear, K should be increased; new equipment should be smaller; meshing The K of the type rotor internal mixer should be smaller than that of the shear type rotor internal mixer; when the upper bolt pressure increases, K should also increase accordingly. In addition, the K of the reverse mixing method must be as large as possible.