**Hydraulic Orifices**

**Their Function:**

Orifices are used in hydraulic systems to restrict flow

**Sizing:**

To calculate the orifice diameter required to pass a desired flow at a specific pressure

**D = 0.23 x √(Q ÷ √Δp)**

Where

Q = Flow in US Gallons per Minute

D = Orifice Diameter in Inches

Δp = Differential Pressure across Orifice

Assuming: Specific Gravity = 1 and Orifice Coefficient = 0.63

To calculate the flow through an orifice of a known diameter at a specified pressure

**Q = (D ÷ 0.23)² x √Δp**

Where

Q = Flow in US Gallons per Minute

D = Orifice Diameter in Inches

Δp = Differential Pressure across Orifice

Assuming: Specific Gravity = 1 and Orifice Coefficient = 0.63

To calculate the pressure drop (differential pressure) across an orifice of a known diameter at a specific flow

**Δp = 〈Q ÷ (D ÷ 0.23)²〉²**

Where

Δp = Differential Pressure across Orifice

Q = Flow in US Gallons per Minute

D = Orifice Diameter in Inches

Assuming: Specific Gravity = 1 and Orifice Coefficient = 0.63