Selection Guide for Rotary Valve Rotors

Operating Conditions

• Medium Characteristics

• Fluid Type: Determine whether the medium is a gas, liquid, or solid particles. For media containing solid particles, a rotor made of wear - resistant material should be selected, such as a rotor with a cemented carbide or ceramic coating. This prevents the particles from wearing the rotor surface, which could affect the valve's sealing performance and service life.

• Corrosiveness: If the medium is corrosive, a corrosion - resistant material should be used, such as a rotor made of stainless steel, Hastelloy, etc. For example, in the chemical industry when handling acidic or alkaline media, a rotor made of ordinary carbon steel will be rapidly corroded, leading to valve failure.

• Viscosity: High - viscosity media may require greater torque to drive the rotor to rotate. Therefore, it is necessary to consider whether the rotor's structure and drive method can provide sufficient torque to ensure the normal opening and closing of the valve.

• Operating Pressure and Temperature

• Pressure Rating: Select a rotary valve rotor with an appropriate pressure - bearing rating according to the operating pressure of the system. Generally, the higher the pressure, the higher the requirements for the strength and sealing performance of the rotor. For example, in a high - pressure steam system, a rotor capable of withstanding the corresponding pressure needs to be selected to prevent leakage or rupture.

• Temperature Range: High - temperature environments can change the properties of materials, potentially causing the rotor to deform, expand, or reduce in hardness. For high - temperature operating conditions, high - temperature - resistant alloy materials can be selected. In low - temperature environments, the low - temperature brittleness of the material should be considered, and an appropriate low - temperature material should be chosen to ensure the normal operation of the rotor at different temperatures.

Valve Performance Requirements

• Flow Coefficient: Select a rotor with an appropriate flow coefficient according to the required flow rate of the system. The larger the flow coefficient, the greater the flow rate of the valve at the same opening. The maximum flow rate requirement of the system can be calculated, and combined with the flow characteristic curve of the valve, the rotor size and type that meet the flow requirements can be determined.

• Leakage Class: If the system has high requirements for sealing performance, such as in some precision chemical or food and beverage industries, a rotor with a low leakage class should be selected. For example, rotors with metal - to - metal or soft - seal structures can achieve different levels of sealing effects, and can be selected according to specific leakage requirements.

• Response Speed: For occasions that require rapid opening and closing, such as emergency shut - off or rapid flow - regulation systems, a rotor with a small moment of inertia and a flexible drive method should be selected to ensure that the valve can quickly respond to control signals and achieve timely control of the flow rate.

Material Selection

• Metal Materials

• Carbon Steel: It has high strength and hardness, and a relatively low price. It is suitable for general industrial applications, such as water and air media under normal temperature and pressure.

• Stainless Steel: It has good corrosion resistance and oxidation resistance, and is widely used in industries such as chemical, pharmaceutical, and food. Different types of stainless steel vary in corrosion resistance and strength, and an appropriate type can be selected according to specific operating conditions.

• Alloy Steel: In harsh operating conditions such as high temperature, high pressure, and high corrosion, alloy steel can provide better performance, such as high - temperature resistance, wear resistance, and fatigue resistance. For example, chromium - molybdenum alloy steel is often used in high - temperature and high - pressure petrochemical pipelines.

• Non - metal Materials

• Ceramic: It has extremely high hardness, wear resistance, and corrosion resistance, and is suitable for handling high - hardness particulate media or highly corrosive media. However, ceramic materials are relatively brittle, and care should be taken to avoid impact and collision during use.

• Plastic: Plastic materials such as polytetrafluoroethylene (PTFE) have good corrosion resistance and self - lubricating properties, and are lightweight and low - cost. They are often used in occasions where high corrosion resistance is required and the pressure and temperature are not high, such as in the transportation system of acid - base solutions.

Drive Methods

• Electric Drive: It has the advantages of convenient operation, fast response speed, and high control accuracy, and can achieve remote control and automated operation. It is often used in industrial systems with high control requirements, such as automated production lines and intelligent control systems.

• Pneumatic Drive: Powered by compressed air, it has the characteristics of rapid action and good explosion - proof performance. It is suitable for occasions with explosion - proof requirements, such as the oil, gas, and other flammable and explosive industries. At the same time, the cost of pneumatic drive is relatively low, and maintenance is relatively convenient.