Make the scraper conveyor last longer

The scraper conveyor is frequently used, so it often encounters problems. If the equipment frequently malfunctions, in addition to requiring maintenance, it will also affect production, waste time, and shorten the service life of the machine. Pengdian Machinery, based on long-term production and service experience, analyzed the factors affecting the service life of the buried scraper conveyor and summarized some experiences to reduce the consumption of the scraper and the bottom plate of the machine chamber, extend the major repair cycle, and share them with you here:

1) Working principle: The materials in the channel are subjected to the pressure of the scraper chain in the direction of movement and the quality of the clinker itself. This generates internal friction between the aggregates, which ensures the stable state of the aggregates and is greater than the external friction resistance generated by the sliding of the clinker in the channel, allowing the clinker to form a continuous overall material flow and be transported.

2) Adjusting the appropriate gap between the scraper and the bottom plate of the machine chamber is a very important issue. It affects the service life of the equipment and the conveying efficiency. Obviously, if the gap is too small, the clinker is prone to get stuck between the scraper and the machine chamber, causing damage to the scraper or the bottom plate of the machine chamber. In severe cases, even a chain break accident may occur. If the gap is too large, the conveying efficiency will be reduced. The gap size depends on the particle size of the clinker. Generally, it is determined by the following formula:

A > D/2 + 5, where A represents the gap between the scraper and the bottom plate (mm); D represents the maximum particle size of the clinker (mm).

After the clinker is cooled by the rotary kiln and cooled by the篦 cooling machine， it is crushed by the hammer crusher. The maximum particle size is about 25mm. The gap between the scraper and the bottom plate should be kept above 17.5mm to reduce the wear of the bottom plate and the scraper and extend their service life.

3) Correct installation and maintenance： Ensure that the specifications of the scraper chain are uniform and the rotating part rotates flexibly.

To ensure the straightness of the inner wall of the machine shell， the interface flange and the guide rail should not have upward or downward misalignment. The connection should be flat without steps. In addition， the interface flange should be straight， and the verticality to the shell should not exceed 1mm to prevent scraping phenomena during the operation of the scraper chain and facilitate normal operation， reducing wear and power consumption. The allowable error of the horizontality of the center line of the head and tail pulleys should be within 6mm， and the head and tail pulleys and the supporting guide rails must be centered， and the horizontality of the center line of the head and tail pulley shafts should be leveled.

Identify the running direction of the scraper chain and do not install it in the reverse direction. Ensure that the scraper chain has an appropriate tension. It should not be too tight or too loose. Adjust the tail device to ensure that the unused travel is not less than 50% of the total length. The output shaft of the motor， the output shaft of the reducer， and the head shaft of the conveyor should be parallel， and the large sprocket should be centered. The axial offset of the two sprockets should be within 2mm.

4) Reasonable design and good manufacturing quality： The scraper is a load-bearing component made of 16Mn steel and directly welded perpendicular to the chain.

The scraper chain is a traction component. Its design is a double-plate chain， formed by stamping two steel plates and welding them into a chain rod， and then connected by a pin shaft. Its characteristics are reliable use， simple manufacturing， and low cost. During operation， the scraper chain has to overcome a large friction resistance， bear a large dynamic load and static load， so it needs to undergo heat treatment after manufacturing and welding to have high strength， toughness， and wear resistance.

The chain plate is quenched and tempered with 45Mn2， with a hardness of HRC62， which has the longest service life. The pin shaft is quenched and tempered with 45 steel or 40Cr， with a quenched hardness of HRC38-43.

5) Correct， reasonable， and timely maintenance： Strengthen inspection efforts， check for any deformation or fracture of the scraper chain， loose pins on the pin shaft， and promptly repair or replace them.

When the scraper chain is loose， it should be adjusted to ensure that the scraper chain works in a suitable tension condition frequently. Identify problems promptly and handle them in time to prevent problems before they occur. Strictly control the gap between the scraper and the bottom plate of the machine chamber. If there is deviation， check it promptly and adjust it.

After implementing these measures, the service life of the scraper conveyor will be significantly extended. The major overhaul period will be extended to 2.5 years, reducing the maintenance workload and production costs. This not only saves resources for the enterprise but also implicitly enhances its competitiveness.