Different types of screw elements can be used in a twin screw extruder. Generally there are four major types of screw elements, namely conveying elements, kneading elements, backward-pumping elements and mixing elements. For each type there are many different subtypes.
The geometry of the conveying elements enables a good transport of the product through the extruder. Each conveying element is characterized by its number of flights, its length in millimeters, and its pitch. The pitch is defined as the axial length in millimeters, required for a complete thread. Conveying elements with a large pitch have a greater conveying effect than those with a small pitch. These elements are used to forward the material e.g. at feed openings, in order to avoid that pressure increases excessively at the openings.
Kneading elements are mostly used for dispersive mixing, but they are also used for distributive mixing processes. They consist of kneading discs with a certain thickness. Like the conveying elements there are several parameters by which the kneading elements are characterized. These parameters include the number of flights, the staggering angle between sequential kneading discs (in degrees), direction (clockwise or counter-clockwise) and the element length (in millimeters) . Except for their mixing properties, kneading elements can also be used for devolatilizing and draining of the substance. Kneading elements with a small staggering angle are also capable to forward the material through the extruder, but therefore their axial mixing effect is less intense. In general, kneading elements with a smaller disc width provide a better distributive mixing than those with thicker discs, which provide a better dispersive mixing.
Backward-pumping elements give a good distributive mixing and as the name implies they transport the product upstream instead of downstream. They are used for performing a more longitudinal homogenization.
Q1: Are you a factory or trading company ? How is you factory extrusion experience?
A: We are factory in Nanjing , 20 years experience on extrusion.Leading supplier in Nanjing city.
Q2:Where is your factory located? How can I visit there?
A : Our factory is based in 77 Tangtong Rd,Hushu,Jiangning District Nanjing , Jiangsu Province, China,
1) You can fly to Nanjing Lukou Airport or you can fly to Shanghai then take high-speed train to Nanjing South Railway Station.
2) We will arrange the pick up in Nanjing Lukou airport or South Railway Station
Q3:What can you provide for after sale service?
A:We can send engineers to your factory for installation and training if customers‘ required
Q4:If we have very special request for the production line,could you help me to do the design?
A:Experienced mechanical designer customized-design provided.
Q5:Could you afford technician team to guide ours installation and commissioning?
A:Experience engineer oversea installation service provided.
Q6: Why choose you ?
A: 1) Quick response. Once we got the inquiries from you, we will reply you within 12hours.
2) Promising leading time. To guarantee the quality, the machine will be finished within max 20days.
3) Before leaving factory, all the machine will be fully tested.
4) Customized package(Wooden) will ensure a safety shipping.