The time required to open and close a valve has more to do with the actuator than with the valve trim.
If the actuator is electric, it's a simple matter of calculating time based on stem travel distance, motor speed, and gear ratio.
If the actuator is pneumatic, the actuation time is a function of air supply pressure, pressure required at the actuator to achieve the desired position, the volume of the actuator chamber, and the restrictiveness of the tubing and other components feeding air to the actuator. This will be a more complicated calculation than for an electric actuator. A crude approximation could be made based on the air flow capacity of the supplying device (I/P, positioner, solenoid -- whatever device controls the air to the actuator), the volume of the actuator chamber, and the desired pressure change inside the actuator to move the valve.
ADDITIONAL DESIGN FEATURES:
● Extended bonnets with sufficient gas column length, usually specified by customer, are supplied for all valves to keep stem packing at sufficient distance away from the cold fluid to remain functional.
● Flexible wedges with CoCr alloy seating faces for cryogenic service.
● Neoflon inserts are available for globe discs.
● Cleaning: All cryogenic valves are thoroughly degreased and cleaned and pipe ends are sealed to prevent contamination.
cryogenic valve refers to the valve that enables to be operated under low temperatures which generally is -40℃.
The cryogenic valve is essential for petrochemical industry, air separation, and natural gas. Its performance can decide the safety of production as well as economy and sustainability of operation. In recent years, the applications of the cryogenic valve have expanded as the demand of the cryogenic valve is increasing.
Applications of the cryogenic valve
The cryogenic valve is mainly used in equipment including the ethylene plant, the LNG terminal, VPSA oxygen plant, the LNG storage tank, the LNG satellite station, the air separation plant, the petrochemical exhaust separation plant the LNG (liquefied natural gas) plant, the liquid oxygen and helium storage tank, the carbon dioxide cryogenic storage tank and car.
Cryogenic media delivered by cryogenic valves include LNG, LPG, ethylene, liquid oxygen and liquid hydrogen. These mediums are not only flammable and explosive, but also will turn into gas with hundreds of times expanded volume when the temperature is increasing. Thus, people need to take these factors into full consideration when designing and selecting the cryogenic valve.
Classification of the cryogenic valve
According to different medium temperature, there is the cryogenic valve and the super cryogenic valve:
Medium operating temperature of cryogenic valves: -100℃≤ t≤-40℃
Medium operating temperature of super cryogenic valves: t< -100℃
Specification, performance parameter and design parameter of the cryogenic valve
Nominal pressure: CLASS150~1500; PN20~250
Nominal diameter: DN15~1200
Connection: flanged (FF/RF/RJ), butt-welded (BW), NPT, socket weld (SW), etc.
Typical materials and the minimum operating temperatures
1 LCB/LCC/ LF2: -46℃
Manual operation, bevel gear operation, electric operation, pneumatic operation, hydraulic & pneumatic operation, etc.
Types of the cryogenic valve
The cryogenic ball valve, the cryogenic gate valve, the cryogenic globe valve, the cryogenic safety valve, the cryogenic check valve, the cryogenic butterfly valve, the cryogenic needle valve, the cryogenic throttle valve, the cryogenic pressure reducing valve, etc.