【2026 Selection Process】Solenoid Valve Selection and Calculation Examples
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I. The core process for selecting solenoid valves A standard and proven approach to selecting solenoid valves typically involves five steps: Step 1: Determine whether the medium is compressed air, vacuum, or some other gas Is there oil mist, water vapor, or corrosive substances? The medium determines the suitability of the sealing material and the valve body.
Step 2: Confirm the pressure range. It’s not enough to only consider the pressure of the air supply; it is necessary to determine: • The minimum operating pressure • The maximum operating pressure • Whether low-pressure/vacuum start conditions exist. The applicable pressure ranges for pilot-operated and direct-acting types are completely different.
Step 3: Determine the required flow rate. This is the most crucial step, as well as the one that is most easily overlooked. The selection of a solenoid valve is not essentially about the size of the interface, but rather whether its flow capacity is sufficient.
Step 4: Select the valve port type – determine it based on control requirements: two-position five-way, two-position three-way, three-position five-way, etc.
Step 5: Match electrical parameters – Confirm the control voltage (24VDC / 220VAC, etc.), determine the PLC output type and its load capacity, and consider the environmental protection rating (dust protection, water resistance, oil mist resistance)
II. The most crucial \"calculation logic\" in solenoid valve selection: The most practical approach in engineering is to first calculate the flow rate required by the system based on the parameters of the cylinder, and then determine the flow capacity required of the solenoid valve (the Kv/Cv value). The core idea can be summed up in one sentence: first calculate how much gas the equipment needs, and then determine whether the valve can supply that amount of gas.
III. Standard steps for calculating flow rate Taking the most common cylinder system as an example: Step 1: Calculate the effective area A of the cylinder = π × D² / 4 (D is the inner diameter of the cylinder, in meters)
Step 2: Calculate the gas volume per stroke, V = A × stroke length (unit: cubic meters, then convert to liters)
Step 3: Calculate the gas consumption per unit time, Q = volume per cycle × number of actions per minute (unit: L/min)
Step 4: Unit conversion Q(m³/h) = Q(L/min) × 0.06
Step 5: Estimate the required Kv value. A commonly used approximation formula in engineering is: Kv = Q / √ΔP (where ΔP is the allowable pressure drop, in bars)