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Control-valve sizing

Two liquid control valve sizing rules of thumb are... [Pg.14]

When the control valve size is established by the designer, for example selecting a CV, it is assumed that this size valve is installed. If the control valve size is later increased it may be necessary to recheck the PR valve relief considerations. [Pg.131]

If the control valve size is critical to the overpressure protection of the downstream equipment, and must not be increased, then this is clearly noted in all relevant documentation (specification sheets, flow diagram, operating manual, etc.,) and a warning notice plate is welded to the valve body. In such cases, an actual check of the valve installed or purchased should be made during the startup review. [Pg.152]

The careful selection and design of control valves is important good flow control must be achieved, whilst keeping the pressure drop as low as possible. The valve must also be sized to avoid the flashing of hot liquids and the super-critical flow of gases and vapours. Control valve sizing is discussed by Chaflin (1974). [Pg.199]

More detailed equations are available in publications of the control-valve manufacturers (for example, the Masonielan Handbook for Control Valve Sizing, Dresser Industries, 6th edition, 1977) that handle flows of gases, flashing liquids, and critical flows with either English or SI units. [Pg.214]

The designer must specify the maximum flow rate that is required under the worst conditions and the minimum flow rate that is required. Then the valve flow equations for the maximum and minimum conditions give two equations and two unknowns the pressure head of the centrifugal pump APj> and the control valve size C . [Pg.218]

Equal-percentage valves are often used when the pressure drop available over the control valve is not constant. This occurs when there are other pieces of equipment in the system that act as fixed resistances. The pressure drops over these parts of the process vary as the square of the flow rate. We saw this in the examples discussing control valve sizing. [Pg.221]

J4. Reactant liquid is pumped into a batch reactor at a variable rate. The reactor pressure also varies during the batch cycle. Specify the control valve size and the centrifugal pump head required. Assume a flat pump curve. [Pg.251]

The design of a chemical engineering system always involves a number of trade-ofls. We have already discussed the conflicts between the process engineer and the control engineer in the question of control valve sizing. There are many other such conflicts between what would be the optimum from only a steadystate standpoint and what is needed to handle the dynamics of the process. [Pg.273]

Rather less freedom is allowed in the construction of mechanical flowsheets. The relative elevations and sizes of equipment are preserved as much as possible, but all pumps usually arc shown at the same level near the bottom of the drawing. Tabulations of instrumentation symbols or of control valve sizes or of relief valve sizes also often appear on P I diagrams. Engineering offices have elaborate checklists of information that should be included on the flowsheet, but such information is beyond the scope here. [Pg.24]

In selecting the control valve size required, first determine the K value required from Eq. (6.14). Since only one A value is involved here, and there is no straight pipe section and we want a 5-psi AP, this equation becomes ... [Pg.231]

For a complete treatment of the many aspects of control valve sizing, refer to the Instrument Engineers Handbook. For some basic equations to calculate the required valve coefficients (C ) for various liquid and gas flow applications using different valve types, refer to Tables 2.66 and 2.67. [Pg.221]

Driskell, L.R., Practical Guide to Control Valve Sizing, Instr.Techn., 14, p.47,1967. [Pg.477]

CONTROL VALVE SIZING FOR LIQUID, GAS, STEAM, AND TWO-PHASE FLOW... [Pg.340]

Control Valve Sizing for Liquid, Gas and Steam Conditions Program Inputs and Outputs... [Pg.382]

FORMAT (//,20X, CONTROL VALVE SIZING FOR LIQUID SERVICE, /, IH, 76(1H ))... [Pg.397]

Valves are generally line size. The maximum control valve size is line size. In most applications, control valves are one size smaller than line size. When a larger pressure drop is available, control valves can be two or three sizes smaller than line size. [Pg.196]

The control valve is sized to be 10 percent open during summer operation, wiien the temperature of the subcooled liquid in the tank is 45°C. Use the control valve sizing formula... [Pg.115]


See other pages where Control-valve sizing is mentioned: [Pg.379]    [Pg.219]    [Pg.234]    [Pg.629]    [Pg.629]    [Pg.153]    [Pg.465]    [Pg.75]    [Pg.456]    [Pg.337]    [Pg.382]    [Pg.382]    [Pg.382]    [Pg.397]    [Pg.80]    [Pg.95]   
See also in sourсe #XX -- [ Pg.398 ]




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