K_BALL_VALVE

Overview

Calculate the loss coefficient (K) for a ball valve using the Crane method.

Excel Usage

=K_BALL_VALVE(D_valve, D_pipe, angle)

• D_valve (float, required): Diameter of the valve seat bore [m]
• D_pipe (float, required): Diameter of the pipe attached to the valve [m]
• angle (float, required): Angle formed by the reducer in the valve [degrees]

Returns (float): Loss coefficient K for the ball valve [-]

Examples

Example 1: Reduced port ball valve at 50 degrees

Inputs:

D_valve	D_pipe	angle
0.01	0.02	50

Excel formula:

=K_BALL_VALVE(0.01, 0.02, 50)

Expected output:

Result
14.0513

Example 2: Full bore ball valve

Inputs:

D_valve	D_pipe	angle
0.05	0.05	0

Excel formula:

=K_BALL_VALVE(0.05, 0.05, 0)

Expected output:

Result
0.0572

Example 3: Small angle ball valve

Inputs:

D_valve	D_pipe	angle
0.04	0.05	20

Excel formula:

=K_BALL_VALVE(0.04, 0.05, 20)

Expected output:

Result
0.4046

Example 4: Steep angle ball valve (60 degrees)

Inputs:

D_valve	D_pipe	angle
0.03	0.05	60

Excel formula:

=K_BALL_VALVE(0.03, 0.05, 60)

Expected output:

Result
5.3478

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.fittings import K_ball_valve_Crane as fluids_k_ball_valve

def k_ball_valve(D_valve, D_pipe, angle):
    """
    Calculate the loss coefficient (K) for a ball valve using the Crane method.

    See: https://fluids.readthedocs.io/fluids.fittings.html#fluids.fittings.K_ball_valve_Crane

    This example function is provided as-is without any representation of accuracy.

    Args:
        D_valve (float): Diameter of the valve seat bore [m]
        D_pipe (float): Diameter of the pipe attached to the valve [m]
        angle (float): Angle formed by the reducer in the valve [degrees]

    Returns:
        float: Loss coefficient K for the ball valve [-]
    """
    try:
        D1 = float(D_valve)
        D2 = float(D_pipe)
        angle = float(angle)
    except (ValueError, TypeError):
        return "Error: D_valve, D_pipe, and angle must be numbers."

    if D1 <= 0 or D2 <= 0:
        return "Error: Diameters must be positive."
    if D1 > D2:
        return "Error: D_valve must be <= D_pipe."
    if angle < 0:
        return "Error: Angle must be non-negative."

    try:
        result = fluids_k_ball_valve(D1=D1, D2=D2, angle=angle)
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

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