Agricultural chemicals and waste management

Checking the efficiency of the field sprayer

Only tested and fully operational equipment may be used for plant protection treatments.

For the performance test, the sprayer must be clean, complete, with the tank filled to 2/3 with clean water. The test is carried out in two stages – a general test and a specific test of the technical condition of individual components of the sprayer. The general test is a visual inspection. This includes checking the completeness and correctness of the fixings of the rotating parts, the state of wear of the liquid and hydraulic hoses, the tank, the valves, the nozzle bodies, the running gear as well as the cleanliness of the tank, any leaks and the fit of the filling dome. The detailed examination includes an examination of the components and systems of the sprayer:

  • examination of the pump, i.e. checking: lubrication system (oil level, leaks), operation of the pulsation dampening system, performance and leakage,
  • agitator test, i.e. checking the agitation effect of the liquid when all spray components are switched on,
  • examination of the tank, i.e. checking: the venting of the tank, the position of the drain valve, which must allow the tank to be completely emptied, the condition of the filling screen or other pre-filtering system, the position and legibility of the liquid level indicator, as well as the tank flushing system, the dilution equipment and the clean water tank,
  • testing of the measuring and control devices, i.e. checking: their location and the accuracy of the manometer readings, the stability and repeatability of the pressure. Tests shall also be carried out to verify the accuracy of the speed sensor indications and the implementation of the application rate by electronic control devices on sprayers which have such equipment,
  • testing of the liquid system, i.e. checking that the system is tight and secured against uncontrolled spraying and self-rotating or sliding during operation,
  • inspection of filters, i.e. checking: their technical condition, number, size of filter meshes on the discharge side of the pump,
  • testing of the nozzles, i.e. checking: their uniformity and characteristics and the uniformity of the discharge rate of the spray liquid. In addition, the operation of the anti-drip valves is checked.

Correct adjustment and lubrication is important for proper boom operation. The correct throttling of the hydraulic oil flow should be checked to prevent damage to the boom during folding and unfolding. The instruction manual for each type of sprayer gives a list of lubrication points for the boom.

It is essential to check the fixings of the liquid tubes and the damage to the hoses. If there are defects, the fixings must be corrected, the hoses replaced, the seals lubricated, etc.

Checking the function of the pressure control valve is done with clean water. If there is leakage in the form of droplets from the nozzles when the main valve is closed, this means that the valve has failed or is worn and must be replaced. Sectional valves must also close completely. Valve leaks can also manifest themselves in the form of false data visible on the computer screen – if the sprayer is equipped with one. All moving valve parts should be lubricated with mineral oil.

The condition of the nozzles is fundamental to the quality of the spray. It is necessary to visually check the spray pattern from the nozzles at normal operating pressure using clean water. For flat spray nozzles, the jet must have a regular fan shape, changes in shape are a sign of damage or wear. Flow calibration using a graduated cup will indicate the degree of wear on the nozzles. Differences in flow must not exceed +10% compared to the tabulated values, if this is not the case, it is necessary to replace the set of nozzles with new ones.

Gauges are generally filled with glycerine and should be protected from frost. A good way to check the operation of a manometer is to fit new nozzles, according to the fluid discharge tables, and carry out a measurement at constant pressure by measuring the fluid discharge into a graduated cup. If the discharge coincides with the tabulated value of the nozzle in question, this means that the manometer is working correctly.

The condition of the drive shaft guards must be checked at all times, lubrication must be provided in accordance with the instructions in the operator’s manual and protection against rotation must be provided by means of chains. It is also important to lubricate the shaft tube profile so that the shaft can move without resistance during operation.

The pump valves should be checked for wear and damage – if necessary, all valves should be replaced with new seals as well. Similarly, the condition of the diaphragms should be checked – if any of them are cracked, they should all be replaced.