Structural Form and Selection of Mixer Upstream System

Generally speaking, mixer upstream system is the professional name of the online automatic batching system for mixer. It mainly includes conveying, storage, automatic weighing and feeding system of carbon black (fillers); conveying, storage, automatic weighing of oil and oil injection system; weighing and feeding system of polymer; dust removal system of mixer, automatic control system. The mixer upstream system in practical industrial production can be composed of the previously described five parts are some parts.

The structural form of mixer upstream system in China can be divided into two categories: stereoscopic upstream system and plane layout upstream system

Stereoscopic Upstream System: it can be two-floor, three-floor or four-floor structure from the plant conditions and model of mixers. Its main features: high weighing accuracy, good stability, adopting screw feeding, wide applicable scope of materials. The overall height of two-floor plant is 11m~15m, mainly applicable to the medium and small mixers (35L~110L). The two-floor structure mentioned here doesn’t only mean the two-floor plant. The two-floor workshop in the form of building a steel platform within a single-floor building with the total height meeting the requirement is also regarded as the two-floor structure. The overall height of three-floor plant is 16m~20m, mainly applicable to the mixers (80L~190L) and the overall height of four-floor plant is 19m~27m, mainly applicable for the mixers (80L or above).

Plane Layout Mixer Upstream System: It is mainly used for the single-floor plant. Its only advantage is that it can be used for the plants with the height only 6m~10m. So the investment of the plant will be smaller and most mixers below 270L can use this system. If we make a comparison only from the use of mixer upstream systems, the higher plants are much better that the lower plant with a tidier and more beautiful layout and more convenient for maintenance. It is very simple to understand that no one would make more  investment on the plants if the lower plants were better. The plane layout mixer upstream system have three types of structures: negative pressure (suction) mixer upstream system, (negative pressure + stereoscopic) combined type mixer upstream system and scraper (flexible screw) mixer upstream system.

The following are the characteristics and features of these three types of mixer upstream systems:

Negative pressure (suction) upstream system is is familiar by many people in the industry. It is not recommended due to its poor weighing accuracy, lack of system stability, high energy consumption (power consumption) and limited applicability to the materials. Many materials are not suitable to be conveyed by the negative pressure.

(Negative pressure + stereoscopic) combined type mixer upstream system is a typically compromised choice to satisfy the weighing accuracy for the plants without sufficient height to hold the stereoscopic mixer upstream system. It has its own advantage because its structure combines the advantages of the lower height requirement of negative pressure upstream system and higher weighing accuracy of stereoscopic upstream system. Its only shortcoming is large area coverage and high equipment investment.

Hereby I recommend another structure of mixer upstream system called scraper mixer upstream system in single-floor plant. It is not familiar by many people, or has not been seen before. So I would like to highlight to introduce it. This system is independently developed to work for the medium or smaller mixing plants with single-floor workshop structure. It is suitable for the lower requirement of plant height (6~10 meters) and it can solve the shortcomings of the negative pressure mixer upstream system such as poor weighing accuracy, limited applicability of materials, poor stability. The carbon black conveying in this system adopts the sealed mechanical conveying mode, so the system is very stable with lower energy consumption and higher weighing accuracy. The system can be applied to carbon black (fillers) for the manufacturers of rubber products. The only shortcoming of this system is that the layout will be difficult and it need work with flexible screw if the number of carbon black is more than 6 kinds.

The research and development and promotion of the plane mixer upstream system is mainly to solve the production needs of the companies who decide to use upstream system in the single-floor factory building. The advantage of this structure is that no special requirement for the height of the plant and it can be applied to all mixers model of 370L and below.

Due to various reasons, many rubber manufacturers, especially rubber products manufacturers, cannot build a four-floor mixing workshop with a height of more than 20 meters like tire plants due to the limited height of the workshop. At this time, it is particularly important to have a stable and reliable plane mixer upstream system under the condition of a single-floor workshop. Under this circumstance, domestic peers (including Taiwan compatriots) have made many explorations and efforts, even bold attempts, for this purpose in recent years. At present, the plane mixer upstream system that can be seen in the mixing workshop of rubber manufacturers mainly has three structural forms: negative pressure mixer upstream system, (horizontal conveying + vertical lifting + horizontal weighing) three-section screw plane mixer upstream system, and scraper mixer upstream system. 

Negative pressure mixer is familiar by many people in the industry, but I don’t recommend to select this due to tis poor weighing accuracy and system stability (easy to block the pipe), high energy consumption (power consumption), poor applicability of raw materials (some materials cannot be ensured to be used regularly or stably under negative pressure such as barium sulfate, silicon dioxide, light calcium, N770, N774, N550, etc., not caused by the wet weather).

Three-section screw plane mixer upstream system (horizontal conveying + vertical lifting + horizontal weighing) can not only satisfy the weighing accuracy but also do not require very high workshop to hold it, so this upstream system has a certain promotion potential. However if there is any shortage in this system, it is the applicability of materials in the vertical lifting section is narrow. Many materials used by the common rubber manufacturers are not suitable for this high-speed lifting mode, which is very easy to cause failure or blockage, thus reducing the stability and applicability of the system.

Scraper mixer upstream system is developed to solve the shortcomings of the above two types of upstream systems using in the single-floor workshop. It doesn’t require very high plant and avoids the shortcomings such as poor weighing accuracy and adaptability of materials and stability of negative pressure mixer upstream system and (horizontal conveying + vertical lifting + horizontal weighing). The carbon black conveying in this system adopts the sealed mechanical conveying mode, so the system is very stable with lower energy consumption and higher weighing accuracy. The system can be applied to carbon black (fillers) for the manufacturers of rubber products. The only shortcoming of this system is that it needs relatively larger area. Currently the scraper mixer upstream system has been selected and used by many companies such as Wuhu Honglian, Hebei Jinxing, Hebei Haorui, Hebei Tabo, Hebei Yuanxin, Weifang Taibang, Wuwei Fuxing Huatong, Liaoning Futai, Hebei Jiunai and etc.

I hope it can provide rational references for friends in the rubber industry when selecting models, solve the problem of selection difficulties when selecting investment models, and select products that are more suitable for the production.

(Information of the Writer: The writer named Han Gaoqian, graduated from Hubei University in 2002 with the major of industrial automation. He worked in Tangshan for two years after graduation and then entered the rubber industry in Beijing. He is dedicated to the research and development, design, programming and debugging of the mixer upstream system, automatic weighing system and pneumatic conveying system of mixing plants. In Year 2009 he founded Beijing Adson Automation Technology Co., Ltd. specialized in mixer upstream system, small chemicals automatic weighing system, pneumatic conveying system, design and consultation services of mixing workshop, workshop dust collection system, deodorization and environmental protection system of the workshop and etc.)