The Significance of Choosing Valves Correctly

Choosing valves correctly is of vital importance for ensuring the safe operation of the equipment, prolonging the service life of the valves, and meeting the requirements for long-term operation of the equipment. Many valve accidents are mainly caused by improper selection of valves. For instance, in cold regions, if cast iron valves are used, water contained in the oil accumulates in the valve body, and during winter, it easily freezes and cracks the valve.

In some pump outlet valves, due to certain reasons, in cases where the required process flow is low and the pump power is large, a method of regulating flow by using a small-diameter gate valve is often adopted. Due to the partial opening of the gate valve plate, vibration occurs, accelerating the wear of the sealing surface between the gate plate and the valve seat, and easily causing valve leakage.

In addition, the quality of the valves has a significant impact on production and use. For example, in a fertilizer plant, a major explosion accident occurred. The cause of the accident was identified as a liability accident caused by serious quality problems with the valves. The cause of the explosion was that the two-stage outlet valves could not withstand the normal working pressure and suddenly burst. The check valve failed, and the semi-water gas in the system rapidly overflowed, mixing with the surrounding air to form an explosive gas space, resulting in a chemical explosion. According to tests, many indicators of this valve did not meet the relevant standards. Moreover, both of these are valves for water, steam, and oil media, not dedicated valves for non-flammable gases. The design department's selection was also incorrect. Therefore, choosing valves correctly is extremely important for the production, safety, long-term operation of the equipment, and improving efficiency.

The principles for selecting valves: For petrochemical production equipment, valves should meet the following basic principles: reliability, meeting the requirements of continuous, stable, and long-term operation. Therefore, the valves selected should have high reliability, a large safety factor, and not cause major production safety and casualties due to valve failures; meeting the requirements for long-term operation of the equipment, long-term continuous production is for efficiency.

In addition, reducing or avoiding "leaks, spills, drips, and oozes" caused by valves. Valves should meet the requirements of the process production. Valves should also meet the needs of operating media, pressure, temperature, and usage. This is the most basic requirement for valve selection. For corrosive media, valves with corrosion-resistant materials should be selected. After the valve is safe and reliable, it should enable operators to correctly identify the direction, opening degree indicators, and signal indications of the valve, facilitating prompt and decisive handling of various emergency faults.

At the same time, the type and structure of the selected valves should be as simple as possible, and the installation and maintenance and repair should be convenient.