the apparatus known per se in the art and shown in fig1 to 4 comprises an electrostatic sprayer 1 including a rotating bowl 12 , disposed substantially on the axis of a loop 20 formed by a transporter 2 . sprayer 1 is maintained at a high potential relative to transporter 2 , which is earthed , by a high voltage source 11 , and incorporates a turbine enclosed within body 10 for rotating bowl 12 at high speed ( up to 60 , 000 revolutions per minute ). the internal surface of bowl 12 is substantially frusto - conical , and paint injected onto this surface is directed towards the edge 12a of the bowl , whence it is projected tangentially in the form of a sheet 14 of atomized paint . at the base of bowl 12 , between the bowl and turbine body 10 , is disposed an annular nozzle 13 supplied with compressed air and formed with outlet orifices which direct jets of air onto the external surface of bowl 12 . these air jets , initially provided primarily to prevent atomized paint reaching sprayer body 10 , distort sheet 14 of atomized paint so that it changes from a plane to a cone with a very large half - angle at the apex . fig4 shows sheet 14 as seen from the edge , in the plane form . transporter 2 comprises a part - circular loop 20 which is almost closed , being in the general shape of the uppercase greek letter omega . the transporter passes from the horizontal section into loop 20 around rollers 21 and 21 &# 39 ;, which thus define the inlet and outlet ends of loop 20 , respectively . the transporter comprises supports for the objects , extending cantilever fashion parallel to the axis of loop 20 . as shown in fig2 these supports have at their rear ends wheels 25 which bear on a rail 26 concentric with loop 20 , so that as they move around the loop the objects are caused to rotate around the support axis . the apparatus shown is used for painting objects which are of small dimensions as compared with the normal distance between the objects and bowl 12 , corresponding in practical terms to the radius of loop 20 . the objects extend along a principal axis which coincides with the axis of the support , this principal axis being that extending along the longest dimension of the object . their dimensions in directions orthogonal to one another and to the principal axis are significantly smaller than this longest dimension . thus the support axes define a part - cylindrical surface coaxial with loop 20 , and the main axes of the objects move over a section 22 of this part - cylindrical surface , delimited by two circles 22a and 22b coaxial with loop 20 . this being the case , the objects will receive atomized paint essentially in the area 15 in which part - cylindrical surface 22 is intersected by sheet 14 . as shown in fig1 and more clearly in fig4 this area 15 is tangential on one side to delimiting circle 22a and on the other side to delimiting circle 22b , so that the objects receive paint over their entire length , while their rotation around the principal axis ensures peripheral coverage . in order that area 15 should be tangential to delimiting circles 22a and 22b , the axis of rotation of bowl 12 is inclined relative to the axis of loop 20 , as shown clearly in fig4 . when developed , area 15 is of sinusoidal form tangential to the straight lines representing the developments of delimiting circles 22a and 22b . the shape of area 15 will be only slightly affected by distortion of sheet 14 to a conical form under the effect of the air blown out by nozzle 13 , in that , as will be understood , bowl 12 would be moved back relative to the axis of loop 20 in order to maintain area 15 between delimiting circles 22a and 22b . given that the transporter runs at constant speed , the geometrical development of area 15 corresponds to the timing diagram for &# 34 ; scanning &# 34 ; of each object by the sheet of atomized paint , the developed length corresponding to the total time of exposure of the object to the paint . as the developed form is at least approximately sinusoidal , the scanning speed is zero at the ends of the object and maximum in the center . in spite of corrections provided by the thickness of sheet 14 and by the presence of the electrostatic field , the paint deposited on the objects is of excess thickness at the ends . fig5 illustrates the process whereby the invention overcomes this shortcoming . fig5 shows again , in schematic form , scanner body 10 , rotating bowl 12 , annular nozzle 13 , transporter loop 20 and the part - cylindrical surface 22 defined by the principal axes of the objects and contained between delimiting circles 22a and 22b . the angle between the axes of loop 20 and rotating bowl 12 has been reduced with the result that the area in which the sheet of paint and part - cylindrical surface 22 intersect covers only approximately half the length , in the axial direction , of the part - cylindrical surface . a first discharge pressure from nozzle 13 is defined so that area 15 in which sheet 14 intersects part - cylindrical surface 22 is tangential to delimiting circle 22a . a second discharge pressure from nozzle 13 is defined so that area 17 in which sheet 16 intersects part - cylindrical surface 22 is tangential to delimiting circle 22b . it will be understood that the second pressure is less than the first , so that the angle at the apex of conical sheet 16 is less than that for conical sheet 14 . to coat the objects with paint , nozzle 13 is fed alternately at the first and at the second pressure defined as explained above , the period of alternation being short as compared with the period for an object to pass around loop 20 . the pressure waveform is shown in line 40 of fig7 on which levels 41 and 42 represent the first and second pressure values , respectively . the strip 122 represents the developed part - cylindrical surface 22 , whereas lines 122a and 122b are respectively the developments of delimiting circles 22a and 22b . the area 115 is the development of the intersection area , alternately 15 and 17 , as &# 34 ; seen &# 34 ; by an object passing around loop 20 . area 115 is the result of the super - position of two harmonic movements , one at the period defined by the movement of an object and the other at the period of alternation between the first and second pressures . it can be clearly seen , even without an in - depth analysis of the distribution , that the excess thicknesses at the ends are attenuated and that the distribution along the length of the object is substantially regular . to give typical orders of magnitude , the diameter of loop 20 is approximately 0 . 5 m and the linear speed of transporter 2 is 10 meters per minute , so that an object passes around the loop in approximately 9 seconds . each object rotates between nine and ten times as it passes around the loop , that is to say it rotates at a rate of one revolution per second . the diameter of bowl 12 is approximately 70 mm and the voltage produced by high - tension generator 11 is approximately 90 kv . the first pressure is approximately 3 bars and the second pressure approximately 1 bar . the pulses of the first pressure last 0 . 25 seconds and repeat at intervals of half a second . the arrangement shown in fig6 may be used to obtain the alternating pressure as shown by line 40 in fig7 . a source of compressed air is connected to an inlet pipe 30 . a first air reservoir 31 is fed from pipe 30 , through a first pressure regulator 31a which is set to the first pressure . a second and similar air reservoir 32 is fed from reservoir 31 , via a second pressure regulator 32a , set to the second pressure . the second reservoir 32 is connected to an outlet pipe 36 to which nozzle 13 is connected via a non - return valve 35 . the first reservoir 31 is connected to outlet pipe 36 through a solenoid valve 33 , the actuator coil 33a of which receives an appropriate signal over a line 34 . valve 33 may instead be pneumatically operated . it will be understood that , when valve 33 is closed , pipe 36 is at the same pressure as reservoir 32 , whereas when valve 33 is open the pressure in pipe 36 is the same as in reservoir 31 . at this time valve 35 opposes air at the first pressure entering reservoir 32 . notice that a substantially equivalent result would be obtained if the second pressure were atmospheric pressure , in other words if nozzle 13 were fed with pressure pulses separated by intervals during which the relative pressure is zero , provided of course that the sprayer with rotating bowl 20 were moved forward . this would mean that the rear part of the intersection area would be less wide , however . the process which has just been described and discussed permits regularization of the distribution of paint along the principal axis of the objects . in some cases certain regions of the object may need to receive a greater quantity of paint ( an area in which the average diameter of the object is larger , for example ). to overcome this problem , pulses of different pressures may be applied with the appropriate sequences . it is also possible to use a nozzle divided into sectors each covering a certain angle around the axis of bowl 12 , a specific modulated pressure being applied to each sector . this arrangement facilitates adjustments . the diagrams in fig8 refer to a nozzle 13 with two sectors 113a and 113b , placed to either side of a vertical plane passing through the axis of the rotating bowl . to sector 113a are applied pulses of pressure varying between levels 52 and 53 , whereas the pulses applied to sector 113b vary between levels 51 and 53 . the development of the intersection area , within strip 222 between the developments 222a and 222b of the delimiting circles , as it is &# 34 ; seen &# 34 ; by an object in motion , corresponds to the superposition of a harmonic displacement with a period corresponding to movement along the loop and two further harmonic displacements , with the periods of the respective pressure pulses , occurring consecutively and of different amplitudes . the representation shows that the quantity of paint deposited in the region adjacent delimiter 222a is substantially less than the quantity of paint distributed over the remainder of the object . fig9 illustrates a nozzle in the form of a toroidal shaped housing 13 , on the front surface of which a generally circular slit 113c , is positioned in a co - axial fashion to bowl 12 , which is illustrated by the dashed lines in fig9 . radial partitions 113d and 113e are provided to divide the nozzle , along a vertical plane , into sections 113a and 113b . fig1 illustrates sections 113a and 113b as each comprising a nozzle . as illustrated in fig3 two conduits for feeding annular nozzle 13 are illustrated which are relatively close to one another , and which are guided to each of the sections of the nozzle . fig1 differs from fig1 only insofar as the single circular slit 113c is replaced by a plurality of orifices 113f which are located circumferentially about the front surface of housing 13 . it will be appreciated that , while retaining rectangular pulse waveforms corresponding to &# 34 ; high / low &# 34 ; or &# 34 ; on / off &# 34 ; pressure modulation , it is possible to vary the pressure levels and the cyclic ratios of the pulses so as to adapt the distribution of paint along the objects to their configuration . at the same time , the oblique disposition of the rotation axis of the bowl relative to the axis of the loop provides a further adjustment parameter . it will be readily appreciated that experience and routine tests will provide for the optimum implementation of the process in accordance with the invention . an important industrial advantage of the process resides in the saving represented by the absence of any mechanical &# 34 ; scanning &# 34 ; device .