Internal plug with cage multi-stage (concentric cage) choke
Concentric cage choke is designed as a robust control choke with multistage trim specifically for applications to avoid cavitation (i.e. water dumping) and for high energy dissipation such as in high-pressure gas production and low noise service. Available in manual configuration with top-mounted hand wheel it is also designed for easy interface with both rotary and linear electric, pneumatic and hydraulic actuators. Range of different sizes and types of end connections and choices of materials make these a versatile choice in severe service applications.
Concentric cage control choke trim
The concentric cage trim is designed so that flow is directed through ports in an 'outer' flow cage and into a chamber inside the trim, it is then directed through ports in further flow cages until it reaches the pressure of the valve outlet. The tortuous routing of the flow uses energy and drops the fluid pressure in stages whilst the internal chambers allow for recovery. Concentric cage trims are designed for specific process conditions where cavitation is predicted to occur and the number of concentric cage trims used depends on the number of stages required to ensure that cavitation eliminated. The concentric cage trim uses a plug moving inside the inner flow cage to control flow. A metal to metal seat below the flow cages ensures a tight shutoff.