Twin Shaft Mixer: Structural and Usage

The mixer is divided into two types according to the structure: single shaft mixer and twin shaft mixer. The single shaft mixer mainly has a good conveying effect, but the mixing effect is relatively poor. The twin shaft mixer has a good mixing effect and smooth conveying effect.

Here is the outline of this article.

Structural features of the twin shaft mixer

The main parts of the twin shaft mixer include the bottom frame, mixing tank body, two mixing shafts, mixing blades, front and rear support body, gears, couplings, reducer, clutch, transmission v-belt, motor, water pipe, and cover plate.

The mixing tank body of the twin shaft mixer is a structural part, with a cover plate, which has a better sealing so that when the mixer mixes various powdery materials, it can avoid the problem of material dust leakage and flutter. The mixing shaft of the twin shaft mixer is an important part. The two mixing shafts rotate in opposite directions and have a bearing housing, a bearing sleeve, a bearing cover, a shaft guard, a mixing blade, and a gear that keeps synchronous and opposite movements. The mixing shaft of the twin shaft mixer is subject to serious wear and tear during operation. A wear-resistant material sheath is installed on the shaft to ensure the service life of the mixing shaft.

Twin Shaft Mixer

Working principle of twin shaft mixer

When the twin shaft mixer is in operation, the material enters the mixing tank through the inlet, and the two mixing shafts rotate in the opposite direction driven by the motor. The mixing shaft is equipped with mixing blades. The stirring blades are distributed in a spiral line on the stirring shaft. The material is pushed by the rotation of the mixing blades and then displaced in the same direction, mixing each other to complete the mixing effect. In the overlapping area between the two mixing shafts of the twin shaft mixer, the rotation direction of different materials squeezed and rubbed each other to improve the effect of material mixing. In short, the twin shaft mixer is the mixing equipment for mixing, squeezing, and homogenizing the materials entering the mixing tank and continuously conveying them to the next process.

The usage of twin shaft mixer

The twin shaft mixer is the ideal equipment for mixing dry powder materials, suitable for mixing with water while conveying dry powder materials, avoiding dust, and evenly humidifying various dry powder mixtures. The mixing time is decided according to the characteristics of the material, so as to determine the length of the mixing tank, pitch and speed. Generally, the water content of the materials mixed by the twin shaft mixer does not exceed 20 %. twin shaft mixer is more commonly used in building materials, energy, medicine, chemical industry, mining, etc. when wetting powder materials or mixing more than two materials. In the brick and tile industry, it is mainly used for mixing and conveying crushed coal gangue, shale, tailings, construction waste, clay, fly ash, and other raw materials.

Installation and maintenance points for twin shaft mixer

The installation and use of the mixing part directly affect the mixing effect of the mixer and production capacity. As the mixing shaft is long and slender, the bearing seat at both ends is far away. Improper installation and use will easily cause the shaft to jump and deform or even break during operation. Therefore, when installing the mixing shaft, the bearing seat should be aligned and leveled, and the two shafts must be parallel. The coupling should be aligned to make the two shafts concentric, and the clearance should be adjusted properly. The fastening bolts should be tightened to prevent the shaft from shaking during operation.

The following points should be noted in use.

a. Whether all fasteners are secure, especially loose foot bolts or bearing seat fixing bolts and damaged bearings or severely worn gears may cause shaft vibration, damage equipment, and cause accidents.

b.The force must be kept even. Uneven supply or foreign objects entering the mud cylinder may cause overload, increase the load and make the shaft vibrate or break.

c. Mixing blades are wearable parts and should be replaced regularly during production. Therefore, the blade and the blade shaft are bolted together in the design to facilitate the replacement. When installing the mixing knife, the bolts should be tightened first to avoid the knife from loosening during operation. The overall spiral direction of the mixing knife should be the same to ensure that the material moves forward when the two shafts rotate in opposite directions. At the same time, the inclination angle of the blade should be the same. In general, the angle between the blade and the shaft cross-section is l5° ~ 25°. When the angle of inclination is too large, the material forward too fast, mixing will not be uniform; when the angle of inclination is too small, the mud is slow to move forward, and the capacity is reduced while increasing the workload of the mixer. To prevent wear and tear, the inner wall of the mixing tank is equipped with a liner. When installing the mixing knife, the gap between the top of the mixing knife and the liner in the circumferential direction should be controlled at 5 mm to 10 mm. The wear and tear of the mixing knife should be checked during use. When the blade is worn out, the gap between the blade and the mixing tank liner will be increased, which will slow down the mixing of the mud and make the mud unevenly mixed. When the blade is seriously worn, it will reduce the output of the equipment, increase the power consumption, and the mixing effect is poor. When the top of the blade wear up to l5 mm ~ 20 mm, should be timely repair or replacement. At the same time, the production process should avoid foreign objects into the mud cylinder (such as stones or iron), resulting in blade breakage.

d. Strengthen the reducer maintenance. Mixer reducer is a continuous heavy-duty equipment, the use of improper maintenance will make the reducer gears quickly wear and even scrap. To reduce gear wear, extend its service life. In addition to regular, quantitative lubrication and oil changes, but also to its coupling maintenance, the bearing housing adjustment at regular intervals. The output shaft of the reducer is mostly cross-slide coupling, and the end clearance of the coupling should be adjusted during maintenance. The end clearance of the coupling with an outer diameter of less than 200 mm is 1 mm to 2 mm, and the radial displacement is not more than 0.2 mm. The end clearance of the coupling with an outer diameter of more than 200 mm is 2 mm to 2.5 mm, and the radial displacement is not more than 0.3 mm. After using the reducer bearing for a period of time, the clearance increases due to wear, the horizontal difference of the shaft increases, and the gear wear is accelerated due to reducer vibration. Therefore, attention should be paid to adjusting the bearing clearance of the reducer to ensure the normal operation of the gear, in order to extend the service life of the reducer.

Parameters of the twin shaft mixer

ModelMotor Power(Kw)A(Mm)B(Mm)C(Mm)D(Mm)E(Mm)F(Mm)Weight(T)
JS 50002X904253243029102175317221
JS 60004X656375296036502180322228
JS 70004X757190324039302180322233
JS 80004X907190324039302180322234

After reading this article, I believe you have a certain understanding of the twin shaft mixer. If you have any questions or want to know more, please leave a comment and let me know.

Also to read:

How to Calibrate Concrete Mixers

Introduction to Continuous Concrete Mixer

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