Rubber and Plastic Extruders and Extrusion Lines - Part 3: Safety Requirements for Traction Devices
1Key Takeaways
The standard specifies the safety requirements for the traction devices used in rubber and plastic extruders and extrusion lines. It covers various aspects including design, construction, installation, operation, and maintenance of these devices. The document provides detailed guidelines to ensure the safe use of tract…
2Expert Interpretation
This in-depth analysis of the GB/T 25431.3-2025 safety standard for traction devices for rubber and plastic extruders covers key technical requirements such as mechanical protection, electrical safety, and control systems. It also provides a complete implementation verification method and noise testing procedures to help companies achieve compliant production.
Background of Standard Revision and Technological Evolution
GB/T 25431.3-2025 "Rubber and plastics extruders and extrusion lines - Part 3: Safety requirements for traction devices" is a comprehensive revision of the 2010 version of the standard, reflecting my country's technological progress and improved standardization in the field of rubber and plastics machinery safety. This revision not only updates the definition of terms, but also puts forward more stringent technical requirements in terms of safety protection, control systems, noise control, etc.
Analysis of Major Technical Changes
Compared with the 2010 version, the new version of the standard has made important adjustments in several key areas:
| Change Areas | Requirements of the 2010 Edition | Requirements of the 2025 Edition | Technical Significance |
|---|---|---|---|
| Definition of Terms | "Belt Winch Type Traction Device" | "Wheel-Belt Type Traction Device" | Unify industry terminology and improve the applicability of the standard |
| Classification of Hazardous Areas | "Entrance Area", "Exit Area" | "Feeding Area", "Discharging Area" | More Accurate Description of Functional Areas |
| Electrical Safety | "Electrical hazards" | "Electrical hazards and electromagnetic interference hazards" | Add electromagnetic compatibility requirements |
| Protective devices | Basic protection requirements | Interlocking protective devices with guard locking | Improve protection reliability |
| Noise control | Basic noise requirements | New normative Appendix B noise test procedures | Quantitative noise control standards |
Detailed explanation of key safety requirements
Mechanical hazard protection system
Article 4.2 of the standard constructs a complete mechanical hazard protection system for different types of Specific protection requirements are specified for each type of traction device (including crawler-type traction devices, belt-type traction devices, winch-type traction devices, wheel-type traction devices, and roller-type traction devices). Feeding area protection requires the use of fixed or interlocked protective devices that comply with GB/T 8196-2018, and safety distances must comply with the relevant provisions of GB/T 23821-2022. For products that pose a risk of inhalation or entrapment, the clearance between the product and the fixed components of the protective device must comply with the requirements of Table 1 of GB/T 12265-2021.
Conveyor area protection emphasizes the combined use of fixed guards and interlock guards, and specifically requires that interlock guards with guard locks should be able to stop driving immediately when opened, and the interlock function performance level should reach PLr=c.
Control system safety requirements
Article 4.4 puts forward systematic requirements for the safety-related components of the control system (SRP/CS):
| Safety function | Performance level requirement | Technical implementation | Verification method |
|---|---|---|---|
| Starting function | PLr=c | Starting only after all safety protection devices are in place | Function test + measurement and calculation |
| Stop function | PLr=c | Category 0/1/2 stop function selection | Appearance inspection + measurement and calculation |
| Emergency stop function /td> | PLr=c | Emergency stop device accessible in hazardous areas | Visual inspection + measurement and calculation |
| Restart function | PLr=c | No automatic restart upon power restoration | Functional test |
Noise control technology innovations
The newly added Appendix B, "Noise Test Procedure," provides standardized test methods for noise control of traction devices:
Test condition requirements: The machine should be tested with the maximum number of conveying elements operating and running at maximum speed without load to ensure comparability of test results.
Measurement method selection: The engineering method (Level 2 accuracy) is preferred. When technically impractical, the simplified method (Level 3 accuracy) may be used, but the justification must be provided.
Declaration Requirements: Noise declarations must use the dual-value notation specified in B.2 of GB/T 14574-2000, including the measured value and measurement uncertainty.
Key Points for Implementation of Verification
Verification Method System
Chapter 5 of the standard establishes a complete verification method system, including three verification methods: visual inspection, measurement and calculation, and functional testing:
Visual Inspection: Applicable to the verification of intuitive safety measures such as the integrity of protective devices and the configuration of emergency stop devices.
Measurement and Calculation: Applicable to the verification of safety parameters that require quantitative measurement, such as safety distances, gap dimensions, and noise levels.
Functional Testing: Applicable to the verification of interlocking functions, emergency stop functions, the effectiveness of protective devices, and other functions that require actual operation.
Identification and Control of Major Hazards
Appendix A lists in detail the major hazards that may exist in traction devices, including:
- Mechanical Hazards: extrusion, cutting, shearing, inhalation or entrapment
- Electrical Hazards: electric shock, burns, electromagnetic interference
- Thermal Hazards: burns caused by contact with hot extruded products
- Noise Hazards: hearing impairment, tinnitus
- Stability Hazards: overturning or unexpected movement
Standardization Requirements for Usage Information
Chapter 6 puts forward systematic requirements for usage information:
Marking and Signs: The traction device must be clearly marked with manufacturer information and machine information, and warning signs should be set for surfaces that exceed the temperature limit.
Instruction Manual: This must include complete information on safety precautions, installation requirements, operating instructions, and maintenance requirements, with particular emphasis on detailed instructions for feeding operations and safe feeding.
Industry Application Recommendations
Design Phase Considerations
Manufacturers should focus on the following during the product design phase:
Integrated Protective Device Design: Incorporate safety protection as an integral part of product design, rather than as an afterthought.
Control System Safety Level: Ensure that all safety-related control components meet the required performance level.
Noise Source Control: Control noise at its source through measures such as optimizing the drive system and adopting low-noise components.
Management Requirements
Users should pay attention to the following during use:
Regular Maintenance and Inspection: Establish a comprehensive maintenance and inspection system to ensure the effectiveness of protective devices.
Operator Training: Strengthen operator safety training, especially on operating procedures in the feeding area.
Noise protection measures: For equipment with excessive noise, effective personal hearing protection measures should be taken.
Benefit analysis of standard implementation
The implementation of GB/T 25431.3-2025 will bring significant benefits to enterprises:
| Benefit dimensions | Specific performance | Quantitative indicators |
|---|---|---|
| Improved safety level | Reduced mechanical injury accident rate | Expected to reduce by 30-50% |
| Improved product quality | Stable traction process improves product consistency | Product qualification rate increased by 5-10% |
| Improved production efficiency | Reduced downtime due to safety accidents | Increased equipment utilization by 8-15% |
| Reduced compliance costs | Unified standard requirements reduce repeated certification | Reduced certification costs by 20-30% |
Through the full implementation of this standard, the safety performance of traction devices in rubber and plastic extrusion production lines will be systematically improved, providing solid technical support for the high-quality development of the industry.