Valve flow calculation | Flow calculation formula for throttle valve What factors affect the stability of throttle valve flow

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What are the flow regulation methods for metering pumps?

2. Calculation formula for flow rate of static balance valve

The core formula for flow rate calculation of static balance valve is: Q=Cv × √ (Δ P/SG) 1. Formula analysis: The calculation of flow rate (Q) depends on three key parameters: flow coefficient (Cv): This is the core parameter for measuring the flow capacity of the valve, and its value is provided by the valve manufacturer, usually found in product samples or nameplates.. Differential pressure (Δ P): refers to the pressure difference between the inlet and outlet of a valve. Specific gravity (SG): The ratio of the density of a fluid to the density of water at 4 ℃. For water, its value can usually be considered as 1

2. The units of each parameter in the formula should be consistent. The commonly used units for flow rate (Q) are cubic meters per hour (m ³/h) or gallons per minute (GPM); The commonly used units for pressure difference (Δ P) are kilopascals (kPa) or pounds per square inch of fluid (psi). 3. Assuming a scenario where the Cv value of a valve is 10, the measured pressure difference before and after the valve is 25 kPa, and the fluid is water (SG=1). Substitute the formula to calculate: Q=10 × √ (25/1)=10 × 5=50 m ³/h.

3. Flow Calculation of Gas Pressure Regulating Valve

The flow calculation of gas pressure regulating valve depends directly on the valve port diameter, inlet and outlet pressure difference, and medium characteristics. The core formula is: Q=5.047 × Cv × √ (Δ P × ρ/ρ _ir), where Cv is the flow coefficient. 1. Calculation Formula and Parameters: The flow calculation of gas pressure regulating valve adopts the internationally recognized flow

coefficient formula: • Basic Formula: Q=5.047 × Cv × √ (Δ P × ρ/ρ _ir) Q is the standard flow rate (m ³/h), and Cv is the flow coefficient, Δ P is the pressure difference (kPa), ρ is the gas density (kg/m ³), and ρ _ir is the air density (1.293 kg/m ³) • Simplified calculation: For natural gas (ρ≈ 0.7 kg/m ³), the formula can be simplified as Q ≈ 3.9 × Cv × √ Δ P2. Key parameter determination of Cv value selection: - Directly refer to the valve technical manual, different diameters correspond to standard Cv values (for example, the Cv value of DN20 valves is usually 4-5) - Common household pressure regulating valve Cv range: DN15 (1.5-2.5), DN20 (3-5), DN25 (6-10) Determination of pressure difference Δ P: - Inlet pressure P ₿ Taken from the outlet pressure of the gas meter (usually 2-3 kPa for residential use) - outlet pressure P ₂ set according to the rated pressure of the gas appliance (natural gas stoves are generally 2.0 kPa) - Example: When P ₁=3 kPa and P ₂=2 kPa, Δ P=1 kPa3. Actual calculation example: Using a DN20 gas regulator valve (Cv=4.5) to transport natural gas (ρ=0.72 kg/m ³) as an example: - Known conditions: P ₁=2.8 kPa, P ₂=2.0 kPa, Δ P=0.8 kPa - Calculation process: Q=5.047 × 4.5 × √ (0.8 × 0.72/1.293) ≈ 5.047 × 4.5 × 0.63 ≈ 14.3 m ³/h - Simplified calculation: Q ≈ 3.9 × 4.5 × √ 0.8 ≈ 3.9 × 4.5 × 0.89 ≈ 15.6 m ³/h. 4. Key points for selection verification - The calculated flow rate should be greater than the maximum gas consumption of the gas appliance (about 1-2 m for household stoves) ³/h, gas water heater about 2-4 m ³/h) - Check flow rate: The gas flow rate in the pipeline should not exceed 15-20 m/s to prevent excessive noise - Pressure stability: steady-state deviation should be less than ± 10%,

Valve flow calculation | Flow calculation formula for throttle valve What factors affect the stability of throttle valve flow

What are the flow regulation methods for metering pumps?

2. Calculation formula for flow rate of static balance valve

3. Flow Calculation of Gas Pressure Regulating Valve

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