Basic parameters to select the right valve for your fluidic application
Selecting the right valve begins with having a few fundamental details ready. These factors allow you to ensure that the valve meets your application's performance, size, and control requirements while avoiding problems like leakage, unstable flow, or inappropriate sizing. Before beginning your valve selection, make sure you are prepared with the following essential parameters:
- Valve type – 2-way or 3-way
- Valve function – On/Off (Switching) or Proportional
- Flow requirement (Q) / Kv or Cv
- Media – what flows through the valve
- Voltage – available on customer side
See below for a detailed explanation of each parameter.
Valve Type – 2-Way or 3-Way
- Determines how many ports are used and how the valve directs flow.
- 2-way valves are perfect for isolation, dosing, or on/off because they only open or close one flow direction.
- 3-way valves are typically used to control pneumatically actuated components, such as cylinders, or to switch between two flow paths.
- Indicate if it’s Normally Closed (NC) or Normally Open (NO).
Valve Function – On/Off or Proportional
- Defines how the valve operates: fully open/closed or continuously variable.
- On/Off valves(Switching valve) provide simple switching control for basic start/stop operations
- Proportional control valves can vary the degree of opening, enabling precise and dynamic control of flow or pressure—e.g., in dosing, mixing, or control loop systems.
Flow Requirement (Q) / Kv or Cv
- Shows the amount of gas or fluid that needs to flow through the valve at the pressure drop you have available.
- Provide the differential pressure (Δp) and the desired flow rate (in L/min (lpm) or gpm) - for instance, "12 L/min at 0.5 bar."
- To accurately size the valve, if available, add the Kv (m³/h @ 1 bar) or Cv (US gpm @ 1 psi) value.
Operating Pressure Range
- Shows the pressure range at which the valve must function securely.
- Define the minimum, nominal, and maximum input pressure.
- Mention, if possible, any vacuum, backpressure, or short-term peaks that your system experiences.
Media – What Flows Through the Valve
- Media determines the selection of suitable materials, seals, and, if applicable, cleaning/purity requirements.
- Name the liquid or gas (air, oxygen, water, reagent, etc.)
- Mention purity, viscosity, and any chemical compatibility issues (such as corrosive or oxygen-service).
Voltage – Available on Customer Side
- Ensures accurate coil and control selection.
- Specify the supply voltage (12 VDC or 24 VDC) and current limit.
- Indicate the control type (on/off, PWM, or analog) and any connector requirements.
Once you have established these fundamental criteria, you will have a great foundation for valve selection. You can also examine a few other characteristics to help you simplify the choices and ensure the valve operates optimally in your specific application. These include:
- Response time (how quickly the valve opens and closes, important for dynamic control)
- Required certifications for compliance,
- Sealing materials for media compatibility
- Space limitations for integration
- Media or ambient temperature ranges to guarantee reliable operation under real working conditions.
Together, these details help engineers fine-tune the valve for maximum performance and long service life.
Even with a careful component selection process, always ensure that valves and other critical components are tested thoroughly in real-life system conditions to verify long-term performance and compatibility.
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