Flow Coefficient Cv vs. Flow Factor Kv
The flow coefficient - Cv - or the flow factor - Kv - are commonly used to specify capacities of control valves.
Flow Coefficient - Cv
It is often convenient to express the capacity and flow characteristic of a control valve in terms of the
- Flow Coefficient - Cv
The flow coefficient - Cv - is based on the imperial units system and is defined as:
- the flow of water through a valve at 60 oF in US gallon/minute at a pressure drop of 1 lb/in2
The flow coefficient is commonly used in the U.S.
Flow Factor - Kv
The metric equivalent of the flow coefficient - Cv - is based on the SI-system and is called the
- Flow Factor - Kv
The flow factor - Kv - is defined as
- the flow of water with temperature ranging 5 - 30 oC through a valve in cubic meters per hour (m3/h) with a pressure drop of 1 bar
The flow factor is commonly used outside U.S.
Converting between Flow Coefficient Cv and Flow Factor Kv
The relationship between Cv and Kv can be expressed as:
- Cv = 1.16 Kv (1)
- Kv = 0.862 Cv (2)
Related Topics
• Control Valves
Control Valve terminology, bodies, trim, flow characteristics, Cv and Kv sizing, noise, actuators and positioners
• Control Valves and Equipment
Sizing and dimensions of control valves & equipment in steam and condensate systems.
• Fluid Mechanics
The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
• Pipe Sizing
Sizing of steam and condensate pipe lines - pressure loss, recommended velocity, capacity and more.
• Piping Systems
Dimensions of pipes and tubes, materials and capacities, pressure drop calculations and charts, insulation and heat loss diagrams.
• Process Control
Instrumentation and process control systems - design and documentation.
• Steam and Condensate
Steam & condensate systems- properties, capacities, pipe sizing, systems configuration and more.
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