Spraying Drone Components: Nozzles, Pumps, Tanks, Meters

An agricultural spraying drone is a flying application system. Beyond the airframe and propulsion, its performance in the field depends on the liquid system — tank, pump, flow meter, nozzles and plumbing — and, for granular products, the spreader. Whether you are buying complete aircraft, replacement parts or components for your own assembly, this guide explains what each part does and what evidence to request.

How the system fits together

A typical liquid system draws from the tank through a filter, pumps the liquid to the nozzles, and measures flow so the controller can keep the application rate steady as flight speed changes. A level or weight sensor tells the controller when the tank is empty. A granular spreader replaces the liquid system for seed and fertiliser. All parts must work with the aircraft's power supply and flight controller, so integration is as important as the individual specifications.

Tank

• Capacity versus payload: a larger tank only helps if the aircraft can lift it with adequate thrust margin and flight time.
• Material and chemical resistance: ask which liquids the tank material is rated for and request compatibility information.
• Filling and cleaning: opening size, filter mesh, drain position and whether the tank can be removed quickly for cleaning or swapping.
• Level sensing: how the system detects an empty or near-empty tank, and how accurate that reading is.

Pump

Both diaphragm pumps and flexible-impeller pumps are offered for spraying drones, usually with brushless motors. Compare them on evidence, not type alone. Ask for the flow–pressure curve at your supply voltage, the maximum continuous flow, behaviour when running dry, priming ability, materials in contact with the liquid and expected service life of wear parts such as diaphragms or impellers. Check the control interface (PWM or CAN) and that the pump accepts your battery voltage.

Flow meter

The flow meter closes the control loop. Two common principles are:

• Electromagnetic meters, which have no moving parts in the flow but only work with electrically conductive liquids.
• Turbine or impeller meters, which work with conductive and non-conductive liquids but have rotating parts that can wear or stick, especially with abrasive or poorly filtered mixtures.

Ask which principle is used, the stated accuracy across the flow range, the calibration procedure and how often field calibration is recommended.

Nozzles

Pressure (hydraulic) nozzles form droplets as liquid is forced through a tip. Droplet size depends on the tip design and operating pressure.

Centrifugal (rotary) nozzles use a spinning disc or cage to break the liquid into droplets, and are designed so droplet size can be adjusted.

Droplet size affects drift and coverage. Nozzle tips are commonly classified into droplet size categories from very fine to ultra coarse under the ASABE S572 standard, and the main purpose of that classification is to indicate off-target drift potential. Product labels in many markets specify droplet size categories, and labels take priority. Ask suppliers for measured droplet spectrum data (for example volume median diameter) at stated pressures, speeds and flow rates, and for the spray width achieved at your intended flight height and speed.

Granular spreader

For seed and fertiliser, ask about the granule size range the spreader handles, how the metering mechanism controls rate, spread width and uniformity test results, hopper capacity and how the system copes with humid or sticky material. Confirm how quickly the aircraft converts between liquid and granular configurations.

Standards

ISO 23117-1:2023 sets environmental requirements for unmanned aerial spraying systems, covering topics such as hoses and connectors, nozzles, filters, measuring systems, cleaning and drift control. It is used together with ISO 16119-1, does not address the safety of people, and does not apply to aircraft with a maximum take-off mass above 150 kg. Ask whether a system has been assessed against it and request the report. Local rules for aerial application vary by country and should be checked separately.

Test data and support to request

• Flow–pressure curves for pumps and flow accuracy data for meters
• Droplet spectrum and spray width data for each nozzle type offered
• Spreader rate accuracy and uniformity data
• Chemical compatibility lists for wetted materials
• Spare parts lists, wear-part intervals and cleaning procedures

Next step

If you are sourcing spraying drones or liquid-system components and need suppliers who can provide this test data, send your requirements through our inquiry form and our team will match you with suitable suppliers.