What kind of pressure does a properly functioning positive cutoff valve supply to the boom when spray flow is stopped?

A properly functioning positive cutoff valve is designed to maintain a specific pressure in the system, ensuring that when the spray flow is stopped, the pressure remains consistent and reliable. In the context of aerial application, this type of valve provides high positive pressure to the boom.

This high positive pressure is crucial because it prevents backflow of chemicals and ensures that the system can quickly resume spraying without delays or pressure drops. Maintaining high positive pressure also keeps the spray lines filled, allowing for effective and even distribution when the application resumes.

In contrast, other options like low negative or atmospheric pressures would not support the operational efficiency or safety required in aerial applications, as they could lead to inadequate spray coverage or contamination risks. A variable pressure might imply instability in the system, which is not ideal for precise application tasks. Thus, high positive pressure is essential for operational efficacy in aerial spraying situations.