The internal mixer is referred to as "mixer", and the full name is called "closed rubber mixer", which is developed on the basis of open mixer. After the invention of the open mill in 1820, the rubber industry has undergone a fundamental change, but due to the many shortcomings of the open mill, such as high labor intensity, low efficiency, large dust, etc., which seriously affect people's health, so people began to consider energy. If the processing equipment is covered with a cover, it will gradually develop into an internal mixer. Because it works in the mixing room, it is called a closed type. Since the work of the open mill is open, it is called an open rubber mill. Generally speaking, it is believed that the internal mixer was invented by Banbury in 1916. In fact, it was first designed by a commercial engineer (British) in West Germany based on the company's prototype machine. Due to its rapid development, the output is also widely used. Wider, so people have always thought that the Banbury mixer was the first to come out.
Since the appearance of the internal mixer, it has shown a series of advantages over the open mixer in the mixing process, such as short mixing time, high production efficiency, easy operation, better overcoming dust flying, reducing the loss of compounding agents, Improve working conditions and reduce labor intensity. Since it was developed based on experience to a large extent, in the early stage of development, there was a statement that plasticizing was inefficient and could not be used for plasticizing, but it has been denied by production practice. Therefore, the appearance of the internal mixer is an important achievement of rubber mixing machinery, and it has still become a typical equipment in plasticizing and mixing, and is under continuous development and improvement. According to foreign statistics, 88% of the rubber materials in the rubber industry are made by internal mixers, and internal mixers are also widely used in the plastics and resin industries. Now - due to the continuous improvement of the metal powder industry, part of it can also be mixed with an internal mixer.
One of the signs of the development of modern internal mixers is high-speed, high-pressure and high-efficiency machines. Usually, those with a rotor speed of 20 rpm are called low-speed internal mixers, those with a rotor speed of 30 to 40 rpm are called medium-speed internal mixers, and those with a rotor speed above 60 rpm are called high-speed internal mixers.
There have been internal mixers with a rotating speed of 80rpm or even higher, and there are also two-speed, three-speed, variable-speed internal mixers with wide adaptability and processing methods for process and performance, and there are also internal mixers with adjustable rotor speed ratios. The operation time is greatly shortened, from 8 to 15 minutes for slow machines in the past to 1.5 to 3.5 minutes, and some even reach 1 to 1.5 minutes (including the process of using the internal mixing method and the supplementary mixing method, etc.).
The structure of the mixer is also constantly evolving. The working process of the internal mixer and the mechanization and automation level of the entire unit are also constantly improving. Program control is adopted. Now, computer control is adopted in large-scale imported machines.
In short, this development is to greatly strengthen the mixing process, improve machine efficiency, reduce manual labor and improve the working environment.
In this violent mixing process, of course, many new problems will be brought. Therefore, for the mechanical research and design, from the kneading system, cooling system, sealing system, feeding and pressing system, unloading system of the machine , transmission system, control system, main parts, materials, technical decisions and theories of various parameters, all need corresponding development to make the machine perform well and provide possible adaptability and adjustability for the production process.
The development status of my country's internal mixer is: before liberation, it was blank, and after liberation, domestic internal mixers have gradually developed. my country's first manufacturer of internal mixers is Dalian Rubber and Plastic Machinery Factory, which first produced PC-2 140/20L internal mixers in imitation of the Soviet Union, and is now changing to 250L and 75/40L internal mixers. Then Shanghai and other places also gradually produced these machines, such as 250/20/40, 75/30/60, 75/35/70, and 50L internal mixer. Recently, F080, F160 and F270 have been produced by imitating the F series internal mixer, all of which have been exported. In addition, it also produced 50L and 70L internal mixers for Japan. Yiyang Rubber Machinery Factory also introduced GK series technology from West Germany to produce GK series internal mixer. F series and GK series are the two most advanced series of internal mixers in the world. Domestic rubber manufacturers have introduced. Our institute has been researching internal mixers, pin rotors, pin mixing chamber mixers, etc.
The development direction of internal mixer: "two big", "two high", "one low", that is, large size (large capacity), high power, high speed, high pressure, low unit energy consumption, the main problem: end face sealing.
