Scraper Conveyor Chains: Structure, Working Principles and Manufacturing Processes

Scraper conveyor chains are critical components in bulk material handling systems. Understanding their structure, working principles, and manufacturing processes can help you select the right chain for your equipment and extend its service life. This guide covers the key aspects of scraper conveyor chains.

Scraper conveyor chains are specialized conveyor chains equipped with fixed scraper attachments. Unlike standard conveyor chains, which primarily provide traction, scraper conveyor chains use the pushing force of the scrapers to move bulk materials along a conveyor trough. They are widely used in grain processing, mining, feed production, chemical processing, and building materials industries.

1. Structure and Working Principles

A scraper conveyor chain mainly consists of four components:

• Chain Body: Carries the load and provides the traction required for continuous operation.
• Scraper Attachments: Directly contact and push the conveyed materials. Common materials include 40Mn, 40Cr, and 20CrMnTi.
• Pins and Bushings: Form the chain joints and allow smooth, flexible movement.
• Connecting Circlips: Secure the scraper connections and help prevent loosening or detachment during operation.

During operation, the motor drives the sprocket, which moves the chain in a continuous loop. The scrapers attached to the chain travel along the conveyor trough, pushing granular, powdery, and small-sized materials from the inlet to the outlet. The basic working principle is simple: the chain provides traction, the scrapers push the materials, and the trough guides the conveying process.

2. Main Advantages and Applications

Scraper conveyor chains offer high load capacity, impact resistance, and efficient material conveying. They can be used for both horizontal and inclined conveying. Their relatively simple structure also makes installation, replacement, and maintenance convenient.

Typical applications include grain processing plants, mining and aggregate facilities, feed mills, chemical plants, and building materials factories. They are suitable for conveying grains, granular materials, feed pellets, coal powder, sand, gravel, and other dry bulk materials.

However, they are generally not recommended for highly viscous, strongly corrosive, or oversized hard materials, as these may cause chain jamming, accelerated wear, and reduced service life.

Based on equipment requirements and operating loads, scraper conveyor chains are commonly available in single-row and double-row configurations. Single-row chains are suitable for light-duty and medium-sized equipment, including grain and feed conveying systems. Double-row chains provide greater load capacity and operational stability, making them more suitable for heavy-duty equipment, mining applications, and high-volume production lines.

3. Key Manufacturing Processes and Quality Control

The manufacturing process generally includes material cutting, chain plate punching and blanking, pin and bushing machining, heat treatment, chain assembly, scraper welding, finished-chain pre-stretching, surface blackening, inspection, and packaging.

Heat treatment, scraper welding, and pre-stretching are particularly important. Pins and bushings require appropriate hardness to ensure wear resistance. Scraper welds must be properly formed without incomplete fusion or slag inclusions. Pre-stretching helps reduce initial plastic elongation during operation.

Quality inspection covers appearance, dimensions, hardness, joint flexibility, and performance testing. The specified hardness ranges are HRC 40–48 for 40Mn pins and bushings, and HRC 58–64 for the surface hardness of 20CrMnTi components.

Chain pitch, inner width, and scraper dimensions must meet drawing requirements. Each joint should move freely without jamming. Pre-stretching and breaking-load tests are also conducted on a sampling basis. During service, the allowable chain elongation should not exceed 2%; chains exceeding this limit should be replaced to avoid the risk of sprocket meshing，chain derailment and jamming.

4. Routine Maintenance

Regularly check chain tension and adjust it when necessary. Keep the conveyor trough clean by removing accumulated dust and foreign materials to prevent excessive wear and jamming. Lubricate the pin areas at appropriate intervals to reduce friction and wear.

Reliable scraper conveyor chain performance depends on proper structural design, material selection, and manufacturing quality. Matech specializes in conveyor chains, precision castings, CNC machining, and customized industrial components, providing suitable technical solutions and manufacturing support based on equipment requirements and actual operating conditions.