For engineers, choosing a control valve for a powder delivery system is a huge challenge. This is because there are a variety of valve options available in the market, but most valves always have such problems when handling powder particles. The powder conveying has higher requirements for valve selection. This article focuses on the essential differences between the design principles of gas and liquid delivery control valves and powder particle delivery control valves. It is hoped that it will be helpful to engineers serving the chemical industry and food processing industry who have requirements for powder particle delivery.
System design engineers often face many options to choose from when designing a conveyor system. The challenge is to choose the most appropriate solution based on the characteristics of the materials being processed and the functions to be achieved by the system. Gas, liquid and powder particles have different requirements for conveying systems, especially valves, due to their inherent characteristics. Gas and liquid are extremely mobile, and can easily move with the butterfly valve discs and traditional gate valves. It is precisely because of the strong fluidity of gas and liquid that the contact surface between the valve seal ring and the butterfly valve disc and the gate valve blade can be completely sealed. Gases and liquids do not have their own problems of cutting and abrasion. Therefore, the valves used to transport gas and liquid are mainly designed with soft elastic materials.
Dry powder granules are more abrasive and less fluid than gas or liquid due to their solid characteristics. Because of the earliest design of traditional valves to handle gases and liquids, the soft elastic seals used are often very easy to be scratched when conveying dry powder particles, making the valves fail to meet the expected design requirements. When the valve is closed, the powder particles are intercepted by the gate knife and build up at the seal ring, which prevents the valve from completely closing. At the same time, the soft seal ring exposed to the direction of the material flow must withstand the continuous impact of the powder particles and be subject to extreme wear. The destructiveness due to such abrasion will exponentially increase as the speed of material flow increases.
Powder conveying system