What happens to nozzle flow rate if the line pressure is decreased?

• A. Decreases
• B. Increases
• C. Has no effect
• D. Varies, depending on the ground speed

Answer: (A)

Flow through a nozzle is driven by the pressure difference across the nozzle. A nozzle is a small orifice, so the amount of liquid that can pass per second depends on that pressure. When line pressure is decreased, less liquid is forced through each second, so the flow rate falls. For most nozzles, the relationship is such that flow rate is roughly proportional to the square root of the pressure, so lowering pressure noticeably reduces flow. Ground speed affects how much area you cover per minute, but it doesn’t change the fact that the nozzle’s flow rate itself drops with lower pressure.