Agricultura – Ştiinţă şi practică no. 1- 2(89-90)/2014 Agriculture - Science and Practice - 49 - THE INFLUENCE OF PTO (POWER TAKE OFF) SPEED ON PRESSURE AND FLOW VARIATION ON THE SPRAYING MACHINES Muntean M.V., O. Marian, I. Drocaş, O. Ranta University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3-5 Manastur street, Cluj-Napoca, Romania; * Corresponding author: mmvali@yahoo.com Abstract. For a proper operation the spraying machines must be tested to establish the parameters for pumps. These papers are presented the results of a test on a piston pump, mounted on the EEP-600 ME spraying machine. It is also shown how the pump flow is modified when the rotation of the PTO and the working pressure are modified. The test results showed us that the change of the PTO rotation influence mostly the pump flow. The pressure influences slightly the pump flow. Keywords: membrane and piston pumps, flow, pressure, testing equipment, spraying machines INTRODUCTION The pumps attached on the spraying machines have an important role in the working process in order to increase the pressure to assured the optimum pulverization, the agitation inside the tank and the refill of the tank. The principal pump types used for spraying machines are: membrane and piston pumps (mostly used on the spraying machines), piston pumps, membrane pumps, reel pumps, centrifugal pumps. The advantages of using these types of pumps are following: high pressures (some pumps up to 50 bars); spraying solution does not come in direct contact with the pistons; the assemble off-centred-piston does not wear because it is merged in oil; easy maintenance and low acquisition cost. Overall, spraying machines work correct if the pump delivers the right flow for the nozzles (at a certain pressure) and in the same times the necessary flow for agitation and homogenization of the solution inside the tank. The equation to determine the flow rate of the pumps is based to the next equation: (1) Where: Q p = necessary flow rate; q d = maximum nozzle flow; n d = number of nozzles;V r = tank volume; k= percent coefficient which indicates the necessary flow rate for agitation. Some FAO recommendations states that the flow rate must assure the optimum functionality for the nozzles at maximum pressure and in the same time to have a 20% reserve necessary to for a good agitation. MATERIAL AND METHOD For experiences, was used a Herbst equipment pump. The main parts of this equipment are illustrated in figure 1. ( ) ( ) k V n q Q r d d p ⋅ + ⋅ =