How to choose drag-chain conveyor?

The reasonable selection of scraper and chain depends on its structure form, chain pitch, scraper pitch and material of construction. When choosing, people should pay special attention to meet the requirements of production capacity, and make the scraper & chain have the adaptability to material.

1. Selection of Scraper Structure Form
The scraper structure form determines the transportation effect of buried scraper conveyor. It could get a good effect through the reasonable selection of scraper. Otherwise, the improper selection of scraper may cause poor transportation effect, even failure.

On the condition of meeting the adaptability to material, the selection principle is to choose the scraper simple in structure. In the specific use, the scraper can be chosen according to the material features (viscosity, suspension property and fluidity), conveyor trough width and conveyor arrangement form.

1) The material has good transportation property: the scraper in simple shape is preferred, such as T-type, V-type, U-type, etc.
The material has small internal friction coefficient, strong suspension property and high fluidity: complex shape scraper should be used, such as H-type.

2) The material has heavy viscosity, or the viscosity becomes big after the material moisture absorption: in order to reduce the material adhesion on the scraper, and unload and clean material easily, it is better to choose simple structure scraper, such as T-type, V-type, U-type, etc.

3) The material is easy to float chain: the scraper can be inclined position welded.

4) The trough width of buried scraper conveyor is smaller: it is appropriate to use simple shape scraper. When the material with large bulk density is transported in bigger conveyor trough, in order to increase the scraper rigidity, it is recommended to use O-type scraper with diagonal strut.

5) The buried scraper conveyor is horizontal installation: T-type, U-type or V-type scraper is generally used.
Conveyor vertical installation: V-type and U-type scrapers in outward form arrangement are usually chosen.
Z-type buried scraper conveyor: V-type scraper in inward form arrangement.
Ring-lock (MK type) buried scraper conveyor: V-type scraper in outward form arrangement.
Planar ring structure (MP type) buried scraper conveyor: L-type scraper in outward form arrangement.
Facade ring structure (ML type) buried scraper conveyor: V-type scraper in outward form arrangement. 

Basic Type of Scraper and Chain Used for Buried Scraper Conveyor

As the traction and load-bearing components of buried scraper conveyor, scraper chain subassembly is generally welded by different types of scrapers and chains, or one-piece casting.
Subject to the gravity and conveyor trough, the material is transported by the thrust from scraper chain subassembly, as well as the friction and lateral pressure caused in conveying process. Therefore, the appropriate selection of scraper & chain influences the conveying and operating efficiency greatly.

 

According to different material property, conveyor trough width and capacity, various types of scraper and chain are chosen to meet the actual operation requirements.
1. The basic type of scraper
Scraper can be classified according to their shapes. There are flat scraper (T-type), framework scraper (U-type, V-type, H-type), side-pull scraper (L-type) and solid angle shape scraper, etc.
U-type and V-type scrapers are most commonly used, and suitable for horizontal, inclined and vertical transmission. 
T-type and L-type scrapers apply to horizontal transmission.
H-type scrapers are appropriate for square cross section conveyor.
Other special type of scraper, such as cleaner scraper, which bottom margin and broadside are installed with rubber sheet, neoprene sheet, leather sheet or canvas sheet, is used to remove the residue remained in the conveyor casing. In order to prevent most viscous material bonded in the inner wall of casing, the manufacturer can install a cleaner scraper every 5 ~ 10 chain link. 
2. The basic type of chain
There are three types of chains used for the buried scarper conveyor, bush roller chain, die forging chain and double chain.
Bush roller chain has the features of flexible rotation, low friction in meshing process, low specific pressure and small abrasion. While the chains must be replaced in pairs because of its heavier weight.
The characteristics of die forging chain are simple structure, light weight, high strength, reliable operation and convenient assembling & dismantling. 
The pitch of double chain is big, so it has the advantages including high carrying capacity, reliable operation and convenient assembling & dismantling. But the disadvantages are heavy weight, and can’t be designed according to equal strength.