COEX-80-2 Double-stage Ceramic Extruder

A. Features of our ceramic extruders

In 2017, our company digested and absorbed the alumina ceramic membrane extruder VAHRS120B with double-stage vacuum exhaust spiral ceramic extruder technology introduced from EAC-Elektro, Germany, In order to better adapt to the needs of the molding and extrusion users of different kinds of ceramic materials, we first used better cost-effective, more targeted and longer service life materials to manufacture the core components of the extruder that deal with the extreme friction wear and corrosion wear conditions of ceramic materials, At the same time, we further optimize the related technology of ceramic extruder, for example, we further optimized the design of the screw combination module structure, Improve the heat exchange performance of the screw, And facilitate the replacement of the screw module; For example, we have further optimized the structural design of the vacuum exhaust chamber, added the flow channel design, eliminate the risk of possible material deformation resulting in pressure leakage in the future. Over the years, our company's ceramic extruder with its more acceptable price and superior performance has been the majority of users at home and abroad welcome.

By December 2021, our company optimized the double-stage vacuum exhaust ceramic extruder with its excellent design and performance, in addition to exporting Poland and other European and American users, but also successfully won the Pakistan national water treatment project bidding, making contributions to the development of another industrial field in the "One Belt and One Road".

So far, our various ceramic extruders have been accepted by ceramic product manufacturers in more fields. In addition to aluminum oxide flat film (pipe) extrusion, they are also widely used inthesilicon carbide extrusion, the activated carbon extrusion, the molybdenum dioxide MoSi2 molding extrusion, the raw material with cement and silica sand wallboard extrusion andthethermal insulation/decoration integrated wallboard extrusion, etc., these extrudershave been widely praised by users at home and abroad in various industrial fields.

B. Structure diagram of COEX-80/80Double-stage ceramic extruder

The picture above does not include supporting devices, such as achiller,acontrol cabinet, etc

C. Main structure of COEX-80-2Double-stege ceramic extruder:

D. Structure and configuration features ofCOEX-80-2 Double-stage ceramic extruder 

1. The L/D ration and motor power of the double-stage ceramic extruder of the model COEX-80-2: 

Upper-stage L/D7.8, matching motor power7.5kW;

Lower-stage L/D9.8, matching motor power11 kW;

2. COEX-80-2 double-stage ceramic extruder specifically designed for the characteristics of high water content of ceramic raw materials, adopta vacuum exhaust system design with high strength to eliminate moisture, that is, the material is extruded from the upperstage into a "vacuum chamber" inan internal negative pressure state, adjust the negative pressure in the vacuum chamber under visible and quantifiable conditions, so as to realize the quantitative moisture elimination function, as shown in the figure on the right.

Material entering the negative pressure vacuum chamber between the upperstage and lower stage, the user can decide whether to open or how much vacuum negative pressure is required to eliminate the required water quantity according to the field production requirements, such as the water content of the product. When the vacuum negative pressure is in a state of disappearance, the vacuum chamberonlyprovides a channel for the mixing material from the upper machine to enter the lower machine smoothly under a  condition of no water loss, so as to realize further fine mixing and pressurization function.

The extruder vacuum chamber is made of transparent acrylic materials to facilitate the field operators to intuitively and accurately control the material vacuum situation;

3. On two feeding sections of the upper and lower extruder of the double-stage machine is equipped with a counter-rotating double screw feeding system designed for the characteristics of ceramic clay material. Unlike polymerrawmaterialsin the extrusion, ceramic mud generally doping have high proportion, as an adhesive of organic cellulose, mud performance high water content and mutual adhesion "ball", fluidity is very poor, leading to the difficulty of extruder feed, sothe  double stage feeding system forceramic extruder is very special direction inward "double wrist" structure design, as shown in the right, in order to realize the mandatory feeding of ceramic mud function;

4. Ceramic materials inside the extruder barrels, there is a very significant, completely different characteristic from other operating materials, that is, hard solid phase ceramic materials“contact and rub” the barrel bore wall and the screw edge surface, which will produce serious "shear force". The shear force will produce a high "shear heat". However, there are certain components of organic cellulose as adhesives in the ceramic material. Once these organic cellulose decompose after bearing high shear heat, its function as adhesives will be greatly reduced or even disappeared.

In order to avoid the "thermal decomposition", in addition to the screw structure design as far as possible to reduce the "shear heat", all the barrels in upper and lower stage of the ceramic extruder are designed with a forced water cooling circulation system inside. With the coordination of circulating water input from an external high-power chiller and set to the temperature required for ceramic material operation, accurate temperature limiting control is achieved for the material temperature inside the extruder.

The water circulation system inside all the double-stage barrels of the designed ceramic extruder is shown in the right figure.

The manufacturing materialfor the double stage machine barrels is 304 stainless steel to prevent corrosion, especially in summer, from condensation water. The barrelinner liners are equipped with a segmented, quenched and hardened 1.4112 (corresponding to the Chinese brand 9Cr18MoV) martensitic stainless steel to resist the extremely severe friction wear and acid-base corrosion wear conditions of ceramic materials mixed with organic cellulose.

5. The modular threaded components are connected to the shaft through splines andget the power torque transmitted by the shaft. Inside the inner of the shaft is installed with a stainless steel pipe, and circulating constant temperature water is sprayed out of the steel pipe and flows back along the inner wall of the shaft, take away the shear hot received by the material, as shown in the following figure: 

6. In view of the extreme serious friction and wear characteristics of solid phase high shear of ceramic "mud material", and the acid and alkaline corrosion characteristics of high water content of mud material, all the core components of ceramic extruder adopt the modular design for convenient replacement. Once the user encounters the extrusion output decline, the extrusion product is unstable and needs to replace the parts, only need to replace the local seriously worn parts to reduce the operating cost of the extruder and quickly restore the production.

The schematic diagram shows rightis the screw design structure and modular thread element code of COEX-80-2 ceramic extruder.

The manufacturing materials of the above modular screw parts are made of martic corrosion resistant stainless steel of 1.4112, and the ultimate quenching hardness can reach HRC 62 or above;

7. In order to meet the user's demand for various products of ceramic extruder molding, including the high size precision requirements of extrusion sheet and tube products, the control system of ceramic extruder configuration needs to achieve the most stringent feedback and closed-loop control on the pressure fluctuation range of operating materials. In order to achieve this goal, the ceramic extruder adopts a PLC programmable logic controller host to accurately control two screw speedby precise PID tuning and closed-loop control of the two main motors of the COEX-80-2 extruder from the upper to lower stages. All of these controls can be easily and intuitively operated through a 10 inc touch screen installed on site. 

To this end, for the lower stage machine which directly for the molding, in front of the molding template configuration with a high-end DYNISCO brand pressure / temperature double sensor, to accurately feedback the pressure and temperature of the nose, makes the closed loop control system can be more accurate and timely monitor material dynamic online condition, as shown in the right.

8. In order to ensure the high reliability and stability of the machine operation, while the pursuit of the lowest running energy consumption, all the main motors on upper and lower stage extruder COEX-80-2 to be set up with high-end Shanghai HaoGuan FCA brand motors, together with two sets of domesic famous Jiale frequency conversion governor, using accurate and reliable frequency conversion speed control mode, so can more strictly control the screw speed to achieve the purpose of accurate control product size, at the same time can achieve the purpose of energy saving, reduce consumption.

E. Main technical parameters of COEX-80-2 Double-stage ceramic extruder:

F. Main configuration of COEX-80-2 Double-stage ceramic extruder:

Chief Engineer's Office / Shanghai Omega Machinery Co., Ltd