Volokolamskoye shosse 89 bld 1, Moscow, Russia +7(495) 215-57-16 info@liansu.ru

The advantages of Liansu Machinery in PVC powder centralized feeding system

conveying


We provide flexible solutions for different factory structures. Generally speaking, for the existing old factory, if its height is limited, we will adjust the appropriate design to maximize the avoidance of additional investment due to "roof breaking" and greatly shorten the construction period of the project. During the implementation of the project, we will encounter the problems of pipe blocking, delamination, off-chain, bridging and so on because of the long distance conveying of powder. The following is a brief introduction of the experience of Liansu Machinery in the plan making, implementation and commissioning.

How to effectively solve the pipe blocking phenomenon of long-distance conveying of powder?

When the "air and material" flow in the pipeline, for those vertical pipe, the air velocity still appears the maximum value at the center of the pipeline. When the material is conveyed in the horizontal pipe, due to the influence of gravity, the closer to the bottom of the pipeline, the denser the material distribution, the greater the resistance of the air, and the smaller the velocity of the airflow. The longer the conveying pipeline, the greater the ‘pressure drop’ at the far end.In order to effectively break the long-distance conveying material in the horizontal pipeline due to the influence of gravity which makes the material adhere to the wall of pipeline, we developed a very small air consumption with the role of spiral air propulsion "booster"(patented product of Liansu) through continuous design and combined with on-site testing. It not only greatly reduces the pipe blocking in the conveying process, but also lightens the burden of separating material from air in the powder receiving bin. 

Optimized overall conveying pipeline design,reducing energy consumption in the process of powder transportation.

In the process of designing the whole conveying pipeline, the energy consumption in the process of "powder conveying" should be reduced as much as possible to ensure that 25-30kg powder is conveyed per cubic compressed air.

In a pneumatic conveying system, the design of a suitable "material-air ratio μ" (that is, the powder conveyed bu per cubic meter of air) : μ=qws/(ρa*qva)

QWS is the flux of powder (kg/h).

ρa is the density of ai (kg/m3).

qva is the air flow rate (m3/h)

Generally speaking, the higher the μ design value, the smaller the air consumption, the lower the unit energy consumption, and the larger the powder conveying capacity. However, if the μ is too large, the pipeline is easy to be blocked, which requires a reasonable design of pipe diameter and bend structure in the overall pipeline design and construction(Ensure minimization of pressure drop on the premise of wear resistance),reasonable pipeline layout and quality control during construction.On the basis of the advantages of the second point mentioned above, we have accumulated valuable practical experience combined with the implementation of numerous projects in the plastic extrusion industry in recent years. 

Reliable patented design of transportation has thoroughly solved the problem of "off-chain" in pipe chain operation and the problem of easy loosening of pipe chain.

After PVC and CaCO3 powder and other solid particles are transported to the terminal "receiving bin", the mixed powder is redistributed through a "pipe chain", which is generally divided into horizontal pipe chain and vertical pipe chain.

For the horizontal pipe chain, because the transmission chain wheel and the running chain are in the same horizontal plane, there is no space for powder and mixed solid particles to accumulate in the transmission box. As long as the chain is tight enough, it is difficult for solid particles to squeeze into the clearance between the transmission chain wheel and the chain, so it is not easy to "drop the chain".However, its shortcoming is: because the chain must be very tight, so the chain link is easy to force and become longer, which not only affects the service life of the chain, but also requires maintenance personnel to inspect and maintain the chain in time.

For the vertical pipe chain, because the transmission chain wheel and the chain are in a plane perpendicular to their own gravity, the chain will not "drop off" even in a relaxed state without external force.However, because the chain wheeland chain are perpendicular to the horizontal plane, the material can easily be brought into the chain wheel transmission boxduring the process of material being propelled by the "chain plate", which leads to a continuous squeeze and accumulation.If the powder is doped with more solid particles, the more easily the particles are squeezed into the chain wheeland chain segments, resulting in ‘jumping over teeth’off chain.

How to find the best solution between the service life of horizontal conveyingpipe chain and the easy drop of vertical pipe chain? We have found a perfect solution through continuous optimization:

Based on the vertical pipe chain, a patented device with mixture (powder + particle) overflow and self-delivery is designed, which can thoroughly solve the problems of chain dropping and easy loosening.

Perfect solution for extruder feeding breaks bridging

For PVC plastic pipe production, because of the poor fluidity of CaCO3 powder, and easy water absorption and agglomeration, for the production of PVC plastic pipe with high calcium content, extruder feeding "bridging" phenomenon has been a "big problem".

Superior electrical control system design and central program control function.

From the feeding station of material to the conveying, metering, mixing and stirring, the secondary conveying of mixing material, the redistribution of mixing material in the pipe chain,which is all included , and finally centralized to the central control room for centralized monitoring(Remote local control is also available).And centralized each actuator status display, fault alarm and report filing functions, we can according to customer needs, make the operation and monitoring screen that customers closely attention,published in the form of Web pages, customers can monitor the status of the centralized feeding system with any mobile terminal.

Case Pic.