1. The diameter of the screw is different
In a conical screw barrel
, the screw head and the screw tail both have the same diameter. In a parallel twin-screw extruder, however, the screw head and the screw tail have different diameters.
As a result, the length diameter ratio is significantly higher in the parallel twin-screw extruder than in the conical twin-screw extruder. The parallel twin-screw extruder has a wider range of application, more power saving and higher output than the conical twin-screw extruder.
The parallel twin-screw extruder also has a more complex transmission system. The transmission system consists of a radial bearing, a thrust bearing and related transmission gear that supports the two output shafts in the transmission gearbox.
The large working torque and load capacity of the transmission system is a major feature of the parallel twin-screw extruder. This is due to the large pressure generated at the head of the screw when the melt is flowing, which results in a strong axial thrust on the screw and requires a bearing to withstand it.
2. The length diameter ratio changes greatly
When selecting a twin-screw extruder, users often wonder whether they should choose a conical or parallel extruder. This question is difficult to answer, because it depends on the plasticizing ability of the extruder and the operating process parameters.
The length diameter ratio of a screw is different between conical and parallel extruders. The conical screw has a larger length diameter ratio than the parallel screw.
This difference is important for the optimum processing behaviour of both screw configurations. A gear pump may be mated to the twin screw extruder for pressure management.
This enables the user to have more flexibility with respect to the extrusion volume. They can also change the rotor speed and die position at different stages in the production process. This can be very useful for certain applications, such as transdermal films/patches and multifunctional medical tubes or micropellets.
3. The structure of the transmission system is complex
Transmission lines are the arteries of our power systems, carrying electric current from substations to end users. They feed into buildings and are regulated by meters that keep track of usage.
The structure of the transmission system is complex, including support towers and protective devices to ensure reliable operation. It also consists of insulators, which must be strong enough to prevent contact with the transmission lines.
Several factors influence the selection of the right type of transmission structures, such as wire orientation, foundation requirements, blow out concerns, and adjacent lines in the same right-of-way. Some of the most common construction types are tangent, angled, and dead-end. These structures are specially reinforced to withstand the stress placed on them by changes in direction.
4. The anti-return bearing has a large bearing capacity
Bearings are a crucial part of a large variety of machinery. They prevent metal-to-metal contact between moving elements, reducing friction and heat generation as well as lowering energy consumption.
They also help keep equipment operating efficiently by restricting axial movement. Depending on the type of bearing, this movement may be limited by a fixed or locating bearing and by the endplay or movement of rotating equipment.
Some common bearing failures are caused by improper lubrication or overheating. Overheating can cause grease to bleed and oxidize, which reduces its effectiveness.
Other common bearing failures include contamination and chipping or fragmentation of a surface coating. This can be caused by dirt, grit, dust, steel chips from contaminated work areas or dirty hands and tools.
To minimize contamination, use non-contact labyrinth seals on the bearing's housing or a shield ring that fits in front of the bearing. Also, make sure to use the proper lubricant and relubricate it at appropriate intervals.Conical twin screw barrel for pvc pipe and pvc profile