Knowledge||Regulator valve terminology and feature summary
Dynamic imbalance force: due to the pressure of the process fluid, produced on the spool at any specified opening
Effective area: In a film actuator, the effective area is the area of the diaphragm that effectively produces the output force. The effective area of the diaphragm may change as it moves, usually at the beginning of the stroke, and at the end of the stroke. The molded diaphragm has a smaller effective area change than the flat diaphragm, so it is recommended to use a molded diaphragm.
Loss of Gas - Off: A state in which the valve shutoff element moves to the closed position when the drive energy is lost.
Loss of air - open: A state in which the valve shutoff element moves to the open position when the drive energy is lost.
Loss of Gas—Safety: A characteristic of the valve and its actuator: when the drive energy supply is interrupted, the valve shut-off element is moved to fully closed, fully open, or left in the last position, and any position is considered It is necessary to protect the process. Failure-safe mode of action may require the use of auxiliary controls connected to the actuator.
Flow characteristics: The relationship between the flow through the valve and the percentage rated stroke when the percentage rated stroke changes from 0 to 100%. This term should always be expressed as an inherent flow characteristic or an installation flow characteristic.
Flow coefficient (Cv value): A constant (Cv value) for a given stroke associated with the geometry of the valve that can be used to measure flow capacity. It is the US gallon of 60 °F water flowing through the valve at a pressure drop of one pound per square inch.
High Pressure Recovery Valve: A valve structure that disperses relatively little fluid energy due to the streamlined internal profile and minimal fluid turbulence. Therefore, the pressure downstream of the valve diversion section will return to a very high percentage of the inlet pressure. DC-type valves, such as rotary ball valves, are typical high pressure recovery valves.
Intrinsic die pressure range: When the pressure inside the valve body is atmospheric pressure, it acts on the diaphragm to generate high and low pressures for the rated spool stroke. This range is usually referred to as the spring setpoint range, as this range will be the valve's range of motion when the valve is set to this operating range.
Intrinsic flow characteristics: The relationship between flow and the travel of the shut-off element as the pressure drop across the valve is constant as the valve moves from the closed position to the nominal stroke.
Install diaphragm pressure range: Under the specified operating conditions of the valve body, it acts on the diaphragm to produce high and low pressures for the rated spool stroke. Due to the forces acting on the shut-off element, the inherent diaphragm pressure range may differ from the installed diaphragm pressure range.
Installation flow characteristics: The relationship between flow and shut-off components as the pressure drop across the valve is affected by changing process conditions as the valve moves from the closed position to the nominal stroke.
Low Pressure Recovery Valve: A valve structure that dissipates a significant portion of the fluid energy due to turbulence created by the contour of the fluid passage. As a result, the pressure downstream of the valve diversion section will return to a smaller inlet pressure percentage value than the valve with more streamlined passages. Although each valve has a different structure, conventional straight-through valves typically have low pressure recovery capabilities.
Spring setting range: Adjust the valve actuator spring adjustment range to balance the actual process force.
Flow capacity: The rated flow through the valve under specified conditions.
Gap flow: The flow below the minimum controllable flow when the shut-off element is not seated.
Diaphragm pressure range: The difference between the high and low pressure range of the diaphragm. This can be considered an inherent or installation feature.
Double acting actuator: An actuator that can provide power in either direction.
Modified parabolic flow characteristics: A flow characteristic that provides an equal percentage of characteristics at the lower stroke of the shut-off element and linearity at the high travel of the shut-off element.
Push down to close the structure: a straight-through valve structure with a shut-off element between the actuator and the seat ring so that the push-out of the actuator pushes the shut-off element toward the seat ring and finally closes the valve. This term can also be used in rotary valve construction. In a rotary valve configuration, the linear extension of the actuator stem moves the ball or valve plate toward the closed position. Also known as positive action.
Push down to open the structure: a straight-through valve structure. Its seat ring is located between the actuator and the shut-off element such that the push-out of the actuator pushes the shut-off element away from the seat, thus opening the valve. This term can also be used in rotary valve construction. In a rotary valve configuration, the linear extension of the actuator stem moves the ball or valve plate toward the open position. (also known as reaction).
Adjustable ratio: The ratio between the maximum flow coefficient (Cv value) and the minimum flow coefficient (Cv value) when the deviation from the specified flow characteristic does not exceed the specified limit. When the flow rate is increased to 00 times the minimum controllable flow, a valve that is still well controlled has a 100:1 adjustable ratio. The adjustable ratio can also be expressed as the ratio between the maximum and minimum controllable flows.
Rated stroke: The distance the valve shut-off element moves from the closed position to the fully open position. The rated full open position is the maximum opening recommended by the manufacturer.
Relative flow coefficient: The ratio between the flow coefficient (Cv value) at the specified stroke and the flow coefficient (Cv value) at the rated stroke.
Seat leakage: The amount of fluid flowing through the valve when the valve is in the fully closed position at the specified differential pressure and temperature
Spring factor: The change in spring force as the length of the spring changes. In membrane actuator regulators, the spring rate is typically expressed in pounds per inch of compression.
Valve stem imbalance force: The net force generated on the valve stem at any position due to fluid pressure.
Shrinkage section: the part of the stream where the flow rate is the largest, the hydrostatic pressure, and the cross-sectional area are the smallest. In a regulating valve, the contraction section is usually located downstream of the actual physical limit.
ANSI: Abbreviation for the American National Standards Organization.
API: Abbreviation for American Petroleum Organization.
ASME: Abbreviation for the American Society of Mechanical Engineers.
ASTM: Abbreviation for the American Society for Testing and Materials.
Automatic Control System: A control system that works without human intervention.
Bode plot: A logarithmic magnitude scale and phase angle plot of a conversion function on a logarithmic baseline. This is the most common form of graphical representation of frequency response data.
Calibration curve: A graphical representation of the verification result. The steady state output of a device is expressed as a function of its steady state input. This curve is usually expressed as a percentage of the output range versus the percentage of the input range.
Calibration cycle: In the range of the meter's range, in the direction of rising and then falling, using the known value of the measured variable, and recording the corresponding output reading value, the calibration cycle curve can be increased by first increasing and then reducing the input of the device. obtain. It is usually expressed as a percentage of the output range as a percentage of the input range. It provides a measure of the return difference.
Gap flow: The flow below the minimum controllable flow when the shut-off element is not seated.
Controller: A device that automatically operates to adjust the controlled variable.
焓: A thermal dynamic quantity, which is the sum of the internal energy of the valve body and its product of volume and pressure: H = U + pVo (also known as heat capacity).
Entropy: A theoretical measure of energy that cannot be converted into mechanical work in a thermodynamic system.
Feedback signal: A return signal obtained by measuring a direct controlled variable. For a regulator with a positioner, the feedback signal is typically a mechanical indication of the position of the shutoff element connecting rod to the positioner.
FCI: Abbreviation for Fluid Control Organization.
Frequency response characteristics: The frequency dependence between the steady-state sinusoidal input expressed in amplitude and phase and the resulting substantially sinusoidal output. The amplitude and phase shift of the output can be viewed as a function of the input test frequency and used to describe the dynamic behavior of the control device.
Hardness: The ability of a metal to resist plastic deformation, usually in the form of a depression. The ability of plastic and rubber to resist the penetration of a pointed tip into its surface.
Oscillation: A vibration with a significant amplitude that still exists after the external excitation has disappeared. Oscillation is sometimes referred to as a loop or a limit cycle. Oscillation is evidence of working at or near the stability limit. In the regulating valve, the instability of the control system or the positioner of the valve can cause fluctuations in the loading pressure of the actuator, and the oscillation will follow.
ISA: Abbreviation for the American Instrument Society. Now known as the International Society for Measurement and Control.
Instrument Pressure: The output pressure provided by an automatic regulator valve to operate the valve.
Loading pressure: The pressure used to position the pneumatic actuator. This is the pressure actually acting on the actuator diaphragm or piston. If the valve positioner is not used, the loading pressure can be the gauge pressure.
NACE: Used to represent the American Association of Corrosion Engineers. As the scope of the organization became more international, the term has been changed to international NACE. NACE is no longer an abbreviation.
0SHA: Abbreviation for the Occupational Safety and Health Act (USA).
Working medium: This refers to a fluid, usually air or gas, that powers the operation of the valve positioner and the automatic controller.
Working limit: A range of operating conditions that a device can withstand without causing permanent damage to the operating characteristics.
Range: The area between two extremes whose spacing can be measured, accepted, or transmitted and expressed as upper and lower range values (eg, 3 to 15 Psi; -4 to 212 °F, -40 to 100 °C).
Repeatability: The proximity of a series of consecutive output measurements for the same input value, along the same direction, under the same operating conditions, over the entire range of travel. It is usually measured as non-repeatable, but expressed as a percentage range. It does not include a return difference.
Sensitivity: The relationship between the change in output amplitude and the change in input that caused the change after reaching a steady state
Signal: A physical variable whose one or more parameters carry information about another variable represented by the signal.
Signal amplitude ordering (split): an action mode in which two or more signals are generated, or two or more terminal control elements are driven by one input signal, each terminal control element being continuously, with Or with no overlap to respond to the amplitude of the input signal.
Range: The arithmetic difference between the upper and lower range values (eg, range = 0 to 150 °F, range = 150 °F; range = 3 to 15 PSig, range = 12 PSig).
Air source pressure: The pressure at the supply port of a unit. Commonly used regulator valve source pressure values range from 20 Psig for 3 to 15 Psig and 35 Psig for 6 to 30 Psig.
Zero error: The error of a device under specified conditions of use when the input is a low range value, which is usually expressed as a desired range of percentages.
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Dynamic imbalance force: due to the pressure of the process fluid, produced on the spool at any specified opening
Effective area: In a film actuator, the effective area is the area of the diaphragm that effectively produces the output force. The effective area of the diaphragm may change as it moves, usually at the beginning of the stroke, and at the end of the stroke. The molded diaphragm has a smaller effective area change than the flat diaphragm, so it is recommended to use a molded diaphragm.
Loss of Gas - Off: A state in which the valve shutoff element moves to the closed position when the drive energy is lost.
Loss of air - open: A state in which the valve shutoff element moves to the open position when the drive energy is lost.
Loss of Gas—Safety: A characteristic of the valve and its actuator: when the drive energy supply is interrupted, the valve shut-off element is moved to fully closed, fully open, or left in the last position, and any position is considered It is necessary to protect the process. Failure-safe mode of action may require the use of auxiliary controls connected to the actuator.
Flow characteristics: The relationship between the flow through the valve and the percentage rated stroke when the percentage rated stroke changes from 0 to 100%. This term should always be expressed as an inherent flow characteristic or an installation flow characteristic.
Flow coefficient (Cv value): A constant (Cv value) for a given stroke associated with the geometry of the valve that can be used to measure flow capacity. It is the US gallon of 60 °F water flowing through the valve at a pressure drop of one pound per square inch.
High Pressure Recovery Valve: A valve structure that disperses relatively little fluid energy due to the streamlined internal profile and minimal fluid turbulence. Therefore, the pressure downstream of the valve diversion section will return to a very high percentage of the inlet pressure. DC-type valves, such as rotary ball valves, are typical high pressure recovery valves.
Intrinsic die pressure range: When the pressure inside the valve body is atmospheric pressure, it acts on the diaphragm to generate high and low pressures for the rated spool stroke. This range is usually referred to as the spring setpoint range, as this range will be the valve's range of motion when the valve is set to this operating range.
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Install diaphragm pressure range: Under the specified operating conditions of the valve body, it acts on the diaphragm to produce high and low pressures for the rated spool stroke. Due to the forces acting on the shut-off element, the inherent diaphragm pressure range may differ from the installed diaphragm pressure range.
Installation flow characteristics: The relationship between flow and shut-off components as the pressure drop across the valve is affected by changing process conditions as the valve moves from the closed position to the nominal stroke.
Low Pressure Recovery Valve: A valve structure that dissipates a significant portion of the fluid energy due to turbulence created by the contour of the fluid passage. As a result, the pressure downstream of the valve diversion section will return to a smaller inlet pressure percentage value than the valve with more streamlined passages. Although each valve has a different structure, conventional straight-through valves typically have low pressure recovery capabilities.
Spring setting range: Adjust the valve actuator spring adjustment range to balance the actual process force.
Flow capacity: The rated flow through the valve under specified conditions.
Gap flow: The flow below the minimum controllable flow when the shut-off element is not seated.
Diaphragm pressure range: The difference between the high and low pressure range of the diaphragm. This can be considered an inherent or installation feature.
Double acting actuator: An actuator that can provide power in either direction.
Modified parabolic flow characteristics: A flow characteristic that provides an equal percentage of characteristics at the lower stroke of the shut-off element and linearity at the high travel of the shut-off element.
Push down to close the structure: a straight-through valve structure with a shut-off element between the actuator and the seat ring so that the push-out of the actuator pushes the shut-off element toward the seat ring and finally closes the valve. This term can also be used in rotary valve construction. In a rotary valve configuration, the linear extension of the actuator stem moves the ball or valve plate toward the closed position. Also known as positive action.
Push down to open the structure: a straight-through valve structure. Its seat ring is located between the actuator and the shut-off element such that the push-out of the actuator pushes the shut-off element away from the seat, thus opening the valve. This term can also be used in rotary valve construction. In a rotary valve configuration, the linear extension of the actuator stem moves the ball or valve plate toward the open position. (also known as reaction).
Adjustable ratio: The ratio between the maximum flow coefficient (Cv value) and the minimum flow coefficient (Cv value) when the deviation from the specified flow characteristic does not exceed the specified limit. When the flow rate is increased to 00 times the minimum controllable flow, a valve that is still well controlled has a 100:1 adjustable ratio. The adjustable ratio can also be expressed as the ratio between the maximum and minimum controllable flows.
Rated stroke: The distance the valve shut-off element moves from the closed position to the fully open position. The rated full open position is the maximum opening recommended by the manufacturer.
Relative flow coefficient: The ratio between the flow coefficient (Cv value) at the specified stroke and the flow coefficient (Cv value) at the rated stroke.
Seat leakage: The amount of fluid flowing through the valve when the valve is in the fully closed position at the specified differential pressure and temperature
Spring factor: The change in spring force as the length of the spring changes. In membrane actuator regulators, the spring rate is typically expressed in pounds per inch of compression.
Valve stem imbalance force: The net force generated on the valve stem at any position due to fluid pressure.
Shrinkage section: the part of the stream where the flow rate is the largest, the hydrostatic pressure, and the cross-sectional area are the smallest. In a regulating valve, the contraction section is usually located downstream of the actual physical limit.
ANSI: Abbreviation for the American National Standards Organization.
API: Abbreviation for American Petroleum Organization.
ASME: Abbreviation for the American Society of Mechanical Engineers.
ASTM: Abbreviation for the American Society for Testing and Materials.
Automatic Control System: A control system that works without human intervention.
Bode plot: A logarithmic magnitude scale and phase angle plot of a conversion function on a logarithmic baseline. This is the most common form of graphical representation of frequency response data.
Calibration curve: A graphical representation of the verification result. The steady state output of a device is expressed as a function of its steady state input. This curve is usually expressed as a percentage of the output range versus the percentage of the input range.
Calibration cycle: In the range of the meter's range, in the direction of rising and then falling, using the known value of the measured variable, and recording the corresponding output reading value, the calibration cycle curve can be increased by first increasing and then reducing the input of the device. obtain. It is usually expressed as a percentage of the output range as a percentage of the input range. It provides a measure of the return difference.
Gap flow: The flow below the minimum controllable flow when the shut-off element is not seated.
Controller: A device that automatically operates to adjust the controlled variable.
焓: A thermal dynamic quantity, which is the sum of the internal energy of the valve body and its product of volume and pressure: H = U + pVo (also known as heat capacity).
Entropy: A theoretical measure of energy that cannot be converted into mechanical work in a thermodynamic system.
Feedback signal: A return signal obtained by measuring a direct controlled variable. For a regulator with a positioner, the feedback signal is typically a mechanical indication of the position of the shutoff element connecting rod to the positioner.
FCI: Abbreviation for Fluid Control Organization.
Frequency response characteristics: The frequency dependence between the steady-state sinusoidal input expressed in amplitude and phase and the resulting substantially sinusoidal output. The amplitude and phase shift of the output can be viewed as a function of the input test frequency and used to describe the dynamic behavior of the control device.
Hardness: The ability of a metal to resist plastic deformation, usually in the form of a depression. The ability of plastic and rubber to resist the penetration of a pointed tip into its surface.
Oscillation: A vibration with a significant amplitude that still exists after the external excitation has disappeared. Oscillation is sometimes referred to as a loop or a limit cycle. Oscillation is evidence of working at or near the stability limit. In the regulating valve, the instability of the control system or the positioner of the valve can cause fluctuations in the loading pressure of the actuator, and the oscillation will follow.
ISA: Abbreviation for the American Instrument Society. Now known as the International Society for Measurement and Control.
Instrument Pressure: The output pressure provided by an automatic regulator valve to operate the valve.
Loading pressure: The pressure used to position the pneumatic actuator. This is the pressure actually acting on the actuator diaphragm or piston. If the valve positioner is not used, the loading pressure can be the gauge pressure.
NACE: Used to represent the American Association of Corrosion Engineers. As the scope of the organization became more international, the term has been changed to international NACE. NACE is no longer an abbreviation.
0SHA: Abbreviation for the Occupational Safety and Health Act (USA).
Working medium: This refers to a fluid, usually air or gas, that powers the operation of the valve positioner and the automatic controller.
Working limit: A range of operating conditions that a device can withstand without causing permanent damage to the operating characteristics.
Range: The area between two extremes whose spacing can be measured, accepted, or transmitted and expressed as upper and lower range values (eg, 3 to 15 Psi; -4 to 212 °F, -40 to 100 °C).
Repeatability: The proximity of a series of consecutive output measurements for the same input value, along the same direction, under the same operating conditions, over the entire range of travel. It is usually measured as non-repeatable, but expressed as a percentage range. It does not include a return difference.
Sensitivity: The relationship between the change in output amplitude and the change in input that caused the change after reaching a steady state
Signal: A physical variable whose one or more parameters carry information about another variable represented by the signal.
Signal amplitude ordering (split): an action mode in which two or more signals are generated, or two or more terminal control elements are driven by one input signal, each terminal control element being continuously, with Or with no overlap to respond to the amplitude of the input signal.
Range: The arithmetic difference between the upper and lower range values (eg, range = 0 to 150 °F, range = 150 °F; range = 3 to 15 PSig, range = 12 PSig).
Air source pressure: The pressure at the supply port of a unit. Commonly used regulator valve source pressure values range from 20 Psig for 3 to 15 Psig and 35 Psig for 6 to 30 Psig.
Zero error: The error of a device under specified conditions of use when the input is a low range value, which is usually expressed as a desired range of percentages.
Huaheng Instrument
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