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)

If you operate like this, the screw conveyor will become a pile of scrap metal soon

Are you complaining that your screw conveyor always have problems and you feel you bought a bad quality conveyor? After reading this article you will change your opinion.
Based our investigation, we find that many users operate the screw conveyor in the way. It will not only result in conveyor damage, but also harm to the operating personnel. Please avoid the following wrong operating methods in order to hope utilize the screw conveyor reasonably.
1.Open the upper cover plate during conveyor running.
Users always open the upper cover in order to observe running situation easily, however, this behavior is forbidden. During running ,if sundries fall into conveyor, the conveyor will break down, such as screw blade deformation, shaft cracking, casing damage, etc.
2.Do not clean the residual material timely after using conveyor .
If the residual material is sticky and corrosive, the blade and shaft will be corroded which will lead to a shorter service life.
3.Motor is overloaded heavily.
It can make motor temperature become too high even it will lead to motor overburning. Please control the feeding flow strictly, vibrating feeder will be a good choice.
4.Do not add lubricating oil for bearing.
The dust can make the lubricating oil become viscous, thus it will influence shaft rotating, so please add oil regularly.
5.The temperature of reducer is too high.
The reason is reducer lack of lubricating oil, please check the oil amount before conveyor running.
6.After shutting down the conveyor, the shaft is forced to stop rotating.
This behavior is very dangerous, it will harm the screw blade, shaft and motor. We should stop the screw conveyor naturally.

Please click website www.pkmachinery.com to know more details.

What should we notice when lubricate the screw conveyor?

The lubrication requirement of driving device, please see the product manual that issued by the supplier.
Oil in proper amount of 2# lubricating grease between cross slide coupling intermediate plate and half-coupling when shut down the screw conveyor.
The bearings inside the tail and head end of bearing seats should be lubricated with 3# calcium base grease, and change the grease every month.

The rolling bearing inside the hanging bearing should be lubricated with engine oil every week. Note: please not oil in lubricating grease to avoid squeezing the sealing ring outside the roiling ring away.

Above mentioned lubrication time is just the minimum requirements, detailed time should be flexible and depends on the operation condition.
 

List of Lubrication parts

No.	Name of Lubrication part	Lubrication material	Lubrication part cycle	Lubrication method
1	Coupling	2# lubricating grease	1000 hours	Lubricator
2	Bearing seat	3# calcium base grease	1 month	Lubricator
3	Hanging bearing （Rolling bearing）	Engine oil	1 week	Lubricator
4	Gearmotor	00# lithium lubricating grease	6 months	Lubricator

Henan Pingyuan Mining Machinery Co., Ltd is the most professional manufacturer of Belt conveyor, and Vibrating screen, Bucket elevator, Screw conveyor, Scraper conveyor using the world's most advanced technology, we are willing to serve every company to meet your custom needs. our goal is "be the future global leader of mining machinery industry". have any questions, please contact us without any hesitation. 

   Tel: +86 373 579 9198

   Fax: +86 373 507 1699  

   info@pkmachinery.com  

   Address: 289 Yellow River Road, Xinxiang City, Henan Province, China

Daily Maintenance for Screw Conveyor

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, it is widely used in chemical, metallurgy, paper making, and construction industries, etc. Below you will see its daily maintenance methods:

1. When operate the screw conveyor, bearings, gears and transmission chain should be added lubricating oil regularly.

2. After machine stops, the spiral blade wear condition should be checked, if wears seriously, please repair welding.

 

3. The conveying capacity can not be overloaded, or the material can’t be discharged which will cause the screw axis bends and box damages.
4.During the operation of screw conveyor, any shrill noise, please open the cover and check, eliminate the noise timely.
Hope above mentioned maintenance will be helpful!

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Henan Pingyuan Mining Machinery Co., Ltd is the most professional manufacturer of Belt conveyor, and Vibrating screen, Bucket elevator, Screw conveyor, Scraper conveyor using the world's most advanced technology, we are willing to serve every company to meet your custom needs. Our goal is "be the future global leader of mining machinery industry". If you have any question, please feel free to consult us (E-mail: info@pkmachinery.com) we will give you accurate and timely service.

Blocking Fault Analysis of Screw Conveyor

Since screw conveyor conveying space is small and it is sensitive to material, intertwining phenomenon is easy to occur when screw shaft rotates, blockage occurs in the place of hanging bearing. So blocking problem is the most common fault of screw conveyor which will affect production and increase power consumption, even the motor will burn out and screw shaft twist off which will affect the normal production. Blocking problem is caused by many reasons, we can take measures to avoid this problems:

 

1. Select reasonable screw conveyor technical parameters, for example, if using low speed screw conveyor the rotating speed can not be too fast.

2. Carry out the operation procedures strictly, non-load start-up and stop to ensure continuous evenly material feeding. 

3. Increase the outlet or extend the chute end dimension to solve the problem of unsmooth discharging or can not discharge material timely .At the same time, you can also install a section of reversed screw blade to avoid blocking. 

4. Clean up the material inside the screw conveyor in order to prevent big impurity or fibrous material enter into thescrew conveyor and occurs blocking.

 

5. Reduce the transverse dimensions of intermediate bearing as much as possible in order to reduce the possibility of material passing through the intermediate bearing.

6. Install a level sensor and blockage sensor which can achieve the purpose of automatic control and alarm. 

 

 

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Henan Pingyuan Mining Machinery Co., Ltd is the most professional manufacturer of Belt conveyor, and Vibrating screen, Bucket elevator, Screw conveyor, Scraper conveyor using the world's most advanced technology, we are willing to serve every company to meet your custom needs. our goal is "be the future global leader of mining machinery industry". have any questions, please contact us without any hesitation.