COEX-120-2 Double-stage Ceramic Extruder

A. Ceramic ultrafiltration membrane product

Ceramic ultrafiltration plate membrane can effectively remove organic matter, suspended matter, toxic and harmful substances (such as radium, arsenic), micro organism, algae and oil in liquid, and is the core and key component of new efficient separation technology. It is a kind of ultra-fine filter membrane with asymmetric structure, which is prepared by sintering process with inorganic materials such as alumina. Compared with the traditional organic membrane, it has the advantages of good chemical stability, good reliability, long service life, small occupation space, excellent pollution resistance and low energy consumption, which represents a development trend of water treatment membrane materials.

The service life of ceramic flat film is 3~5 times longer than that of polymer film, the membrane flux is 3~10 times higher, the consumption of chemical agent is reduced by 50 times, the cost of operation and maintenance and energy consumption are reduced by more than 50%. the contamination, chemical cleaning and oxidation of polymer ultrafiltration membranes are an inevitable conundrum, while ceramic membranes are easier to clean, more resistant to contamination, and there is no risk of oxidation. 

Our company overcome difficulties, based on German EAC-Elektro company alumina ceramic membrane extruder technology of double-stage vacuum exhaust spiral ceramic ultrafiltration membrane extruder model VAHRS 120B, to meet the needs of domestic users. Not only we use better cost-effective manufacturing materials that our extruder could be cheaper, but also we have further developed the technology of ceramic extruder, such as we fully localized extruder optimizes the structural design of the replacement module and facilitates the maintenance of the extruder, and the vacuum chamber structure design is optimized to eliminate the defects such as possible leakage pressure due to deformation. Therefore, the extruder is superior to imported extruder in some performance.

B. Structure diagram of COEX-120-2 Double-stage ceramic extruder

Structure diagram of COEX-120-2 Double-stage ceramic extruder

C. Main structure of double-stage COEX-120-2 ceramic extruder:

Main structure of double-stage COEX-120-2 ceramic extruder


D. Structure and configuration features of double-stage COEX-120-2 ceramic extruder:

1. Length to diameter ratio(L/D) and motor power of the extruder:

A. The upper-stage machine L/D8, matched motor power11kw;

B. The lower-stage machine L/D10, matching motor power18.5kw;

2. COEX-120/120 double-stage ceramic extruder is specially designed for high-water content inside the ceramic raw materials, a vacuum exhaust system with high intensity for water removal is designed, that is, the materials are extruded from the upper-stage machine into a "vacuum chamber" with negative pressure inside, and the negative pressure in the vacuum chamber is adjusted underavisible and quantifiable conditions, so as to realize the quantitative water removal function, as shown in the right figure.

The negative pressure vacuum chamber from the upper stage machine to the lower stage machine can be opened or the required vacuum negative pressure value can be determined by the user according to the on-site production requirements, such as the water content of the product and other standard requirements to remove the required quantitative water. Under the closed state of negative pressure, the vacuum chamber provides a channel for the materials mixed in the upper stage machine to smoothly enter the lower stage machine under the condition of no loss of moisture, so as to achieve further fine mixing and pressurization functions.

The vacuum chamber of the extruder is made of transparent acrylic materials to facilitate the on-site operators to intuitively and accurately control the material vacuumization;

COEX-120/120 double-stage ceramic extruder

3. The feeding section of the upper and lower extruders of the double-stage extruder is equipped with a counter screw feeding system designed for the characteristics of ceramic mud. Different from extrusion of high polymer materials, ceramic mud is generally mixed with organic cellulose with high proportion as the adhesive. The mud has high water content and mutual adhesion "agglomeration", with very poor liquidity, resulting in difficult feeding of extruder. Therefore, the two-stage feeding system of ceramic extruder adopts a special inward "double wrist" structure design, as shown in the right figure, to realize the forced feeding function of ceramic mud;

feeding section of the upper and lower extruders of the double-stage extruder

4. When ceramic materials are operating inside the extruder barrel, there is a very obvious feature that is completely different from other operating materials. That is, the hard solid phase ceramic materials will generate serious "shear force" when contacting with the barrel inner wall and the screw, and the shear force will generate very high "shear heat". However, there is a certain component of organic cellulose as an adhesive in the ceramic material. Once these organic cellulose decompose after withstanding high shear heat, its function as an adhesive will be greatly reduced or even destroyed.

In order to avoid this "thermal decomposition", in addition to the structural design of the screw to minimize the "shear heat", the upper and lower stages of the two-stage ceramic extruder are all designed with forced water cooling circulation system inside the modular cylinder. Under the cooperation of the circulating water input by the external high-power water chiller and set as the temperature required for the operation of ceramic materials, Realize accurate temperature control for the material temperature in the extruder.

The water circulation system inside the double-stage cylinder of the ceramic extruder is designed as shown in thebelow right figure.

The barrel of the double-stage cylinder is made of 304 stainless steel to prevent the corrosion of condensation water, especially in summer. The cylinder liner is lined with segmented, hardened 1.4112 (corresponding to Chinese grade 9Cr18MoV) martensitic stainless steel inner liner to resist the extremely severe friction wear and acid-base corrosion wear of ceramic materials mixed with organic cellulose.

Ceramic materials inside the extruder barrels

5. Aiming at the characteristics of high acid and high alkali corrosion working conditions of ceramic raw material formula, the extremely serious friction and wear characteristics of ceramic "mud" under high shear of solid phase, and the acid and alkali corrosion characteristics of high water content of mud, the core components of ceramic extruder are of convenient and more interchangeable modular design. Once the extrusion output is reduced and the extrusion product is unstable and the parts need to be replaced, the user only needs to replace the parts with serious local wear to reduce the operation cost of the extruder and quickly restore the production.

The following diagram shows the screw design structure and modular thread element code of COEX-120/120 ceramic extruder:

   screw design structure and modular thread element code of COEX-120/120 ceramic extruder

The above modular screw components are made of special wear-resistant and corrosion-resistant martensitic stainless steel, and the ultimate quenching hardness can reach HRC 62 or above;

6. In order to meet the user's requirements for various products molded by ceramic extruder, including high dimensional accuracy requirements for extruded diaphragm (pipe) products, the control system configured for ceramic extruder needs to realize the strictest feedback and closed-loop control for the pressure fluctuation range of operating materials. In order to achieve this purpose, ceramic extruder adopts PLC programmable logic controller host to precisely control the screw speed output by the secondary main motor, that is, to realize the accurate PID setting linkage closed-loop control of the two main motors of COEX-120/120 extruder from the upper to the lower. All these controls can be intuitively operated through the 10-inch touch screen installed on the site.

For this purpose, for thelower-stage machine directly acting on the forming, a high-end American DYNISCO brand pressure/temperature dual sensor is configured in front of the forming template to accurately feed back the pressure and temperature information of the material in front of the head, so thatthe closed-loop control system can more accurately and timely strictly monitor the dynamic online status of the material, as shown in the right figure.

120 extruder

7. In order to ensure the high reliability and stability of the operation of the machine, while pursuing the minimum

For energy consumption during operation, the upper and lower main motors of COEX-120/120 extruder are of high-end Shanghai Haoguan brand and the supporting domestic Jiale variable frequency governor, and the accurate and reliable variable frequency speed regulation mode is adopted. In this way, the screw speed can be controlled more strictly so as to achieve accurate control of product size, energy conservation and consumption reduction.

E. Main technical parameters of COEX-120-2 Double-stage ceramic extruder:


Upper-stage Extruder

Bottom-stage Extruder

Raw material

For example: Pure Alumina Ceramic with 15~20% water and 2~4% binder Methylcellulose or HPMC

Feeding system

304 stainless steel hopper, twin screw forced feeding in counter-rotating way

Under a vacuum negative pressure, twin screw forced feedingin counter-rotating way

Main motor and power

High reliability variable frequency gear motor, 11 kw

High reliability variable frequency gear motor, 18.5 kw

Barrel inner diameter (mm) and Manufacturing Material

¢120, Barrel body made of 304 stainless steel. There are liners inside all the barrels made from martensitic stainless steel 1.4112 withquenched HRC 56~58

¢120, Barrel body made of 304 stainless steel. There are liners inside all the barrels made from martensitic stainless steel 1.4112 withquenched HRC 56~58

Screw Diameter (mm) and Manufacturing Material

¢117.5, Same as barrel liner manufacture material 1.4112

¢117.5, Same as barrel liner manufacture material 1.4112, and some is made by PM-HIP

ScrewL/D ratio



Screw Speed (rpm)



Screw maximum thrust



Screw bearing torqueunder a maximum speed (Nm)



Vacuum exhaust system

Germany Busch brand, modelR5-Single stage oil rotary vacuum pump. 

Motor power 0.75kw,final vacuum 0.1hPa (mbar), maximum speed 1800rpm, maximum vacuumpumpingrate: 30m3/hr

Temperature control


One dual-system chillers with a refrigerating capacity of 12

horsepower with 32078Kcal/hr, lift 17MH, and compressor power 4.5KW×2, installed capacity 12.4KW

Barrel and screw

temperature control method

Constant temperature and soft water circulation outside barrel

Constant temperature and soft water circulation outside barrel and inside the screw core

Barrel and screw

temperature control range



Material temperature

control range and precision



Temperature control

section on barrel

3 Sections

5 Sections

Backpressure on material



Center height (mm)




120kg~250kg/hr, the different material formula, the different process and the different product, then the different maximum

capacity. For example a raw material with4.0g/CM3 density, max. capacity will be round 200kg/hr  

Installed capacity (kw)


Normal production power



Exterior dimensions (mm)

Length 3500 × Width 1100 × Height 2000

Full weight (kg)


F. Configuration and characteristics of COEX-120-2 Double-stage ceramic extruder:

We make the COEX-120-2 Ceramic plate (tube) extruder, the first pursuit of configuration is the stability and reliability when the extruder in process. The second goal is to give full play to the advantages of our first brand of extruder heart parts in China, we use the PM-HIP stainless steel imported from Europe to get a high corrosion resistance and high wear resistance feature, to get a longer service life of extruder. Modular design is used in the designing of core components to facilitate the replacement of easily damaged parts and reduce the maintenance cost of extruder.

According to the above ideas, ourCOEX-120-2 ceramic extruder configuration as follows:

Power system

Motor/ reducer combination

Two stage extruders equip high-endandhigh-torque variable-frequency speed regulating motor made in China,

It has characteristics of compact, not occupy position,large load torque, stable and reliable, and long service life


sion system


tion box

The radial bearing of torque distribution system adopts NSK bearing, gear is high speed heavy load hard tooth surface, gear shaft material 20 CrNi2MOA with HRC 58~62

Extrusion system


Stainless steel hopper, stainless steel hardened driven screw forced feeding structure in counter-rotating way

Double-stage barrel

External circulation constant temperature water control temperature, internal replaceable wear-resistant corrosion-resistant stainless steel lining combinedbarrel

Double-stage screw

Hardened stainless steel screw elements and some HIP screw elements combine on top-wear position. Inside second stage screw core, a soft water circulationto be designed for strengthening temperature control

Exhaust system

Vacuum exhaust

A world leading vacuum pump professional manufacturer Germany Busch brand to be equipped, innovative technology of oil-free claw vacuum pump, to ensure a strong, economic, efficient, reliable and mute operating state, with high efficiency, no oil, no contact operation, no maintenance of high-end performance.


ture control system

Accurate tempera-ture control

One air-cooled dual-system chiller is mainly equipped with compressors imported from Europe, America and Japan, Danish Danfoss and American Eco throttle parts, and high efficiency evaporators and condensers. The normal temperature water is cooled to the set temperature through the compression mechanism of the chiller to control the operating temperature of each barrel and screw section of the extruder.

Electronic control system

A touch

control screen plusa

vertical electric control cabinet

Using human-machine interface HMI system of domestic high-end Xinjie brand, window type 10-inch touch screen, with Xinjie brand PLC programmed logic controller host, implement precise control of the system, realize the PID setting linkage control of two main motors of double stage extruder.The operation control functions and the main configuration of double-stage machine control system are as follows:

1. Set the screw speed of the upper stage machine as the set value from the touch screen, to control the 11KW Jiale frequency converter drive motor, to realize the precise control of the power of the upper stage machine;

2. Set the screw speed of the lower stage machine from the touch screen as the given value, control the 18.5KW Jiale frequency converter drive motor, to achieve the accurate control of the power of the lower stage machine;

3. The PLC mentioned above can perform PID control of the extruder through analog communication for data acquisition and processing. For example, according to the back pressure change of the feedback by the pressure sensor installed on the nose, the power system of the extruder host can be accurately controlled, so as to realize the accurate matching of the speed of the upper and lower stage screws, so as to control the material back pressure and melt flow, realize the closed loop control, and realize the automatic operation and control purpose of the extruder. These functions of the PLC control system, compared with the ordinary extruder only using the manual control mode of the instrument display, its automation advantages are incomparable;

4. Display the second order motor parameters from the touch screen, could manually adjust the speed of the second stage screw, and display the detection value of the vacuum (negative pressure) sensor, and start / stop the vacuum pump, see the following example control interface:

5. Using a human-machine interface HMI system of domestic high-end Xinjie brand, window type 10-inch touch screen, with Xinjie brand PLC programmed logic controller host, implement precise control of the system, realize the PID setting linkage control of two main motors of double stage extruder. The operation control functions and the main configuration of double-stage machine control system are as follows:

operation control functions 

6. The temperature and pressure values detected by the lower stage pressure / temperature double sensor on the touch screen are shown in the above design figure, and the system is designed with extruder pressure protection and early warning function;

7. Electrical parts of control cabinet, including contactor, air switch and solid state relay, are mainly using French SchneiderSchneiderBrand, in pursuit of high stability and high control system reliability.


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