Why does Screw Conveyor Occur Material Backflow

As we all know, screw conveyor has widely application in various industries, such as building materials, chemicals, power, metallurgy, coal carbon, food and other industries, and could be suitable for horizontal or inclined conveying. During operation of screw conveyor, once there are materials blocked in hanging bearing, which is called material backflow. If screw conveyor always occurs the phenomenon of backflow, then it will cause screw conveyor throughput greatly decrease. With regard to large capacity screw conveyor, the material backed flow is likely to undermine reducer, and result in reducer overburn as well as economic losses.

If it is seen from transportation process of screw conveyor, the speed of controller and slipping material determines the speed of material which is conveyed from screw conveyor. What’s more, conveyor filling coefficient determines the discharge time, and the speed is large or small depends on the size of screw arbor and motor. Therefore raise these two components size can successfully address the material backflow problem.

What is the working preparation for screw conveyor installation?

1.The screw conveyor foundation should be completed before installation for 20 days which will make the foundation secure and reliable,and will prevent screw conveyor from sinking and deformation to ensure screw conveyor with enough stability when running.
2.The casing installation should accord with following stipulation:
(1)Allowed longitudinal straightness error is 1/1000 of length,total length error is 3mm.
(2)Allowed horizontal straightness error is 1/5000 of width.
(3)The inner wall of the casing is equal to the two sides of the screw blade,and the error is allowed to be 2 mm,the bottom interval error is ±2 mm.
(4)The connection of casing should be closely,and no interval is allowed.
(5)The casing should be fully contacted with structure support.
3.Allowed overlap error of center line between shaft and bearing is 0.5mm.
4.There should be no apparent height difference between two adjacent casings.
5.Please adjust and steady casing before tightening foundation bolts.
6.Output shaft of driven device should be in the same axis line with screw conveyor shaft.
7.If the inlet and outlet need to be installed on site,please weld them after fixing the total machine.

Introduction of Cement Screw Conveyor

CUSTOMER REFERENCE LIST (YEAR 2012-2014)
NO.	EQUIPMENT	VENDOR'S SCOPE OF SUPPLY	QUANTITY	TIME
		PROJECT LOCATION
9	Screw Conveyor	Ukraine	2 Sets	20120829
19	Screw Conveyor	Britain	4 Sets	20130503
21	Screw Conveyor	Zambia	2 Sets	20130508
26	Screw Conveyor	Ukraine	2 Sets	20130924
30	Screw Conveyor	Vietnam	2 Sets	20131108
37	Screw Conveyor	Philippines	2 Sets	20140304
50	Screw Conveyor	Russia	3 Sets	20141103

► Brief Introduction
Cement screw conveyor is bulk material handling equipment, which usually consists of a tube containing either a spiral blade coiled around a shaft (sometimes called an auger), driven at one end and held at the other. The main parts include tube, shaft with spiral blades, inlet and outlet chutes, as well as driving device.
► Working principle
Within a tube, the LSY screw conveyor uses a rotating helical screw blade, to move granular and powdery materials. Cement screw feeder is usually installed at a incline in many industries, such as concrete mixing station, bulk material transit storage, etc.

cement screw conveyor

► Main Features
1.Simple structure, good sealing, easy operation and low power invest cost.
2.It has the features of small screw diameter, high rotation speed and large capacity, specially suitable for inclined transport. The angle is up to 60 degree.
3.Widely used in chemical, metallurgy, paper making, and construction industries, etc.
4.Axle head and conveying spiral adopt spline connection, with features of convenient mounting&disassembling, large load capacity and stability.
5.All sections of screw conveyor are connected with flange. Also screw blades are integral connection.
6.Inlet and outlet chutes have many kinds of connections, such as flange, sack, universal joint, etc.

► Selection condition

Primary considerations for the selection of a screw conveyor are as follow:

    1.Type and condition of the materials to be handled, including maximum particle size, and, if available, the 

specific bulk density of the material to be conveyed.

    2.Quantity of transported material, expressed in pounds or tons per hour.

    3.The distance for which the material is to be conveyed.

Below is the necessary information for the selection of a screw conveyor system, presented in a series of five 

steps. These steps are arranged in logical order, and are divided into separate sections for simplicity. The five  steps are:

    1.Establishing the characteristics of the material to be conveyed.

    2.Locating conveyor capacity (conveyor size and speed) on capacity tables.

    3.Selection of conveyor components.

    4.Calculation of required horsepower.

    5.Checking of components torque capacities (including selection of shaft types and sizes)