| Valve Selection |
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How to Select a Valve
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2. Determine the Valve Control Form Required
3. Determine the Required Cv |
For Control Form VF, VP and VS (floating and proportional control), go to the section valve sizing to determine the Cv needed for the application. To determine Cv , the following parameters must be identified:
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4. Select the Valve Body ted valve body. Remember that ON-OFF control action requires an electric actuator that uses the stem-up open version of the valve body only. If the selected electric actuator is a spring return type, the valve can be configured normally open or normally closed as determined by assembly of the actuator linkage. For Control Form VF (floating), only an electric actuator and only the stem-up open version of the valve body that meets the application criteria may be used. Make sure the valve body has a pressure rating equal to or greater than the fluid pressure. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve. For Control Form VP or VS (proportional control applications) using electric actuators, you may select only the stem-up open version of the valve body that meets the application criteria (stem-up closed actuators require a hydraulic actuator). Make sure the valve body selected has a pressure rating equal to or greater than the fluid pressure. If the selected actuator is a spring return type, the valve can be configured normally open or normally closed as determined by the selection of the actuator. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve. For Control Form VP or VS (proportional control applications) using electric actuators, you may select only the stem-up open version of the valve body that meets the application criteria (stem-up closed actuators require a hydraulic actuator). Make sure the valve body selected has a pressure rating equal to or greater than the fluid pressure. If the selected actuator is a spring return type, the valve can be configured normally open or normally closed as determined by the selection of the actuator. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve. |
5. Select the Actuator
Control Form VA
Control Form VC Control Form VF |
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Control Form VP These actuators may be configured for normally open or normally closed operation by the assembly of the appropriate actuator linkage. Check the close-off pressure table to determine if the EA4x actuator has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables. Electric Rotary Actuator, proportional control with slidewire feedback, non-spring return, dual contact input For proportional control action with non-spring return, the medium torque models EA52, EA54, EA56 and EA58 and high torque EA76 electric actuators with dual contact input may be used. Check the close-off pressure tables on page 5–22 to 5–24 to determine if the EA5x or EA76 actuator has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables. Check the close-off pressure table to determine if the EA42-A or EA44-A actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected.
Control Form VS |
torque spring return actuators and are selected for normally open or normally closed operation. Check any temperature restrictions on use of this actuator as noted on the temperature tables. Electric Rotary Actuator, proportional control, nonspring return, analog input The new EAxx-A Series of box style actuators with integral microprocessor based electronics is also available in non-spring return versions. The EA52-A, EA54-A, EA56-A and EA58-A medium torque actuators and EA76-A high torque actuators have non-spring return action and accept analog input signals. Check the close-off pressure table to determine if the EAxx-A actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables. Electric Linear Actuator, floating control with nonspring return and optional analog input The MF-63123 non-spring return linear stroke electric actuator with floating input (Control Form VF) may be converted to an analog input actuator (Control Form VS) by the addition of an optional analog input card (MFC-420 for current or MFC-8000 for voltage). Check the close-off pressure table to determine if the MF-63123 actuator with analog input has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables.
Options |
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6.
Select the Linkage Kit
7. Valve Assemblies vs. Valve Components |
Control Form (VA, VC, VF, VP, VS). Only those entries in the column “Available factory assemblies” may be ordered as full assemblies. Note that the actuator received with this assembly must conform to the configuration of the actuator specified for that entry. Any other actuator configuration of options not specifically delineated cannot be ordered as a factory assembled valve. If the selected assembly is not listed as an available factory assembly, the valve assembly must be ordered as body, actuator and linkage components and assembled locally using the complete instructions provided with the linkage kit. When ordering the valve body, actuator and linkage separately, the full model numbers for these components must be specified (see the Actuators section of this catalog). |
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| Last Updated Tuesday, July 25, 2006 |