Control valves normally used in plants are Globe type single seated or double seated. For clean services, guiding to be from top and bottom/cage type.
Valve Selection Criteria
For highly viscous services and pump around circuits, cage guiding to be avoided .If cage valve are to be provided due pressure drop requirements, the same shall be with up-stream strainer arrangement to prevent plugging of cage by fines .
Control valves are preferred to be flange type because of ease of maintainability. Welded type control valves avoided for any service, unless otherwise indicated or very high pressure service or gas service.
For all valves with temperatures above 200°C, valve bonnets shall be with radiation fins extension bonnets.
Block valve are of line size and bypass valve control valve body size. Drain valve size are generally be ¾” gate valve and provided with Blind flange.
