Old K says every week – talking about things in the petrochemical design industry. Post 50: The handwheel of control valves and valve assemblies

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This post was last edited by henglinkou on 2021-5-29 at 15:51. Old K’s weekly series – Talks about things in the petrochemical design industry, Post 50: Handwheels on control valves and valve assemblies. Whether handwheels or valve assemblies should be installed on control valves depends on the operational requirements of the plant and units, as well as physical properties and safety regulations; there is no one-size-fits-all solution. The following explanation can be used as a reference. 1) Control valves installed on pipes 2 in (1 in = 0.0254 m) or larger shall be equipped with handwheels. 2) If a handwheel is provided, an operation bypass may not be necessary; one of the two is chosen. The function of the bypass valve is to manually control the flow rate during startup or when the control valve fails. 3) The three-way valve should be equipped with a handwheel. 4) The boiler feed water valve should be equipped with a startup bypass. 5) If the material contains particles or its viscosity is high when the machine is in operation, a bypass is required. 6) When the normal operating pressure difference is greater than 10 bar, consider installing a bypass. 7) When the steam operating pressure difference is greater than 8 bar, considering the installation of a bypass is advisable. 8) Parallel control valve, operated in a one-in-one-backup configuration; no handwheel or bypass is required. 9) The air conditioning control valve shall not be equipped with a handwheel or bypass. 10) The emergency stop isolation valve shall not be equipped with a handwheel or bypass. 11) The fuel control valve shall not be equipped with a handwheel. Tip: You can enter “Lao K’s Weekly Updates – Talks on Matters in the Petrochemical Design Industry” into the website’s search engine to view previous posts