How to Use Valves in the Chemical Field

Valves play a crucial role in various chemical industrial processes, serving as essential components for controlling, directing, and regulating the flow of fluids within pipelines. Correct selection, operation, and maintenance of valves are paramount for ensuring the safety and efficiency of chemical systems. Additionally, valves are subjected to diverse operating conditions, including variations in temperature, pressure, and the nature of the medium being handled, highlighting the importance of material selection and manufacturing processes in valve production.

Valve Characteristics:

Valves exhibit three main characteristics: usage, structure, and actuation. The usage characteristics encompass the valve's category, type, key components, and actuation method. Structural characteristics determine aspects such as installation, maintenance, and repair requirements, including valve length, connection type, sealing mechanisms, and stem processing. Actuation characteristics involve the methods by which valves are operated, whether through external forces or internal mechanisms.

Valve Inspection:

Upon delivery, valves should undergo thorough unpacking and inspection to verify compliance with order specifications. Factors such as quantity, size, pressure rating, materials, appearance, and accessories should be meticulously checked. Following acceptance, valves should be stored indoors, with large-diameter valves receiving outdoor storage with protective measures. Valves designated for direct installation at construction sites require cleanliness and protection against dust and debris.

Valve Testing:

Valves must undergo strength and sealing performance tests prior to installation, with low-pressure valves subjected to spot checks and medium/high-pressure valves undergoing 100% testing. Pressure testing should be conducted gradually to avoid sudden pressure increases and potential accidents. Proper pressure gauge selection and adherence to test time and requirements are essential. Critical valves should undergo multiple tests to ensure compliance with safety standards. Throttle valves may undergo strength and sealing tests without dynamic sealing assessments.

During testing, valve closure should be manually performed by individuals with normal physical strength, without the use of tools except in specific circumstances. For valves with upper sealing structures, packing gland inspection is crucial to detect leakage. Valves equipped with driving mechanisms should undergo combined testing to evaluate actuation performance. Grease application on sealing surfaces should be avoided during testing, except for grease-sealed plug valves. Upon successful testing, valves should be cleaned, test records maintained, and openings sealed to prevent contamination.