Dust leakage challenges in pneumatic conveying systems within the cement industry

Our Thailand customers frequently encounter issues with pneumatic valves used in the cement production process, such as poor sealing or damaged seals, making them a major source of dust leakage. This not only leads to significant loss of valuable raw materials and products, directly increasing production costs, but also causes serious environmental pollution on site and poses risks to equipment operational safety.

The customer contacted us, asking us to provide him with an effective solution to address the dust leakage issue.

Root cause analysis of leakage: Why do ordinary valves tend to leak

Analyzing the cause of the leakage is the first step in choosing the correct solution. Under the high pressure, high speed, and high maintenance conveying conditions of cement powder, general valves usually encounter the following challenges:

1. The sealing forms designed for liquids (such as elastic valve seats) are prone to failure under the continuous infiltration and erosion of fine powder particles, resulting in the formation of leakage channels.
2. The cement powder is abrasive. The valve plate and valve body materials will wear out over time due to continuous erosion, resulting in an increase in the clearance between them and causing the seal to fail.
3. During the opening and closing process of the valve stem, dynamic sealing is required. Powder is prone to enter this area, causing the valve stem to get stuck and the sealing ring to wear out, thereby creating leakage points.
4. The pressure and temperature fluctuations caused by the system's start-up and shutdown, as well as changes in operating conditions, will exert stress on the valve components, affecting the tightness of the sealing surfaces.

Structural solution: Application of dedicated pneumatic powder butterfly valve

1.Optimized design and material selection for pneumatic powder butterfly valves in the face of wear conditions

The long service life of the valve is the foundation for preventing leakage due to wear. Key measures include:

• The smooth flow channel design and the lightweight structure of the cast aluminum valve body can reduce material accumulation and local turbulence, thereby lowering the risk of wear.
• For different types of powders, we offer a variety of valve plate options. For instance, smooth-surfaced and high-hardness stainless steel valve plates are suitable for fine powders that are prone to adhesion; while polyurethane valve plates with low surface energy and certain elasticity can reduce the adhesion of certain viscous materials.

2.Implement a sealing system that achieves "zero leakage"

• The valve seat seal (such as EPDM rubber) not only provides sealing, but its elastic design can also remove the adhered layer on the surface of the valve plate when it rotates.
• Sealed chamber is formed by using at least two high-quality O-rings, and food-grade lubricating grease can be filled in between to create an effective particle barrier zone.

3.Ensure the execution and drive of reliable actions

• Using double-acting or single-acting (spring-return) pneumatic actuators, stable and rapid driving force is provided, ensuring that the valve can fully close or open against the material pressure. The spring-return type can also automatically return to the safe position in case of a power failure.
• The Pneumatic actuator can be equipped with electromagnetic valves, limit switches, position feedback devices, etc., to achieve linkage with the central control system and real-time monitoring of the valve status.

The dust leakage control in the pneumatic conveying system of the cement industry can be significantly enhanced by using wear-resistant pneumatic butterfly valves that are optimized for the characteristics of the powder. This enables enterprises to fundamentally improve the sealing integrity of the pipelines.