EP0132062B1 - Pulvérisation électrostatique - Google Patents

Pulvérisation électrostatique Download PDF

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Publication number
EP0132062B1
EP0132062B1 EP84304256A EP84304256A EP0132062B1 EP 0132062 B1 EP0132062 B1 EP 0132062B1 EP 84304256 A EP84304256 A EP 84304256A EP 84304256 A EP84304256 A EP 84304256A EP 0132062 B1 EP0132062 B1 EP 0132062B1
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EP
European Patent Office
Prior art keywords
nozzle
capacitor
generator
high voltage
liquid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84304256A
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German (de)
English (en)
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EP0132062A1 (fr
Inventor
Colin Grant Maclaine
David James Owen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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Filing date
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Priority claimed from GB838319225A external-priority patent/GB8319225D0/en
Priority claimed from GB838319226A external-priority patent/GB8319226D0/en
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
Publication of EP0132062A1 publication Critical patent/EP0132062A1/fr
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Publication of EP0132062B1 publication Critical patent/EP0132062B1/fr
Expired legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
    • B05B5/053—Arrangements for supplying power, e.g. charging power
    • B05B5/0531—Power generators

Definitions

  • This invention relates to electrostatic spraying.
  • An apparatus of the kind described in the first part of claim 1 is disclosed in US-A-3212211.
  • One form of electrostatic spraying apparatus for example for agricultural or horticultural use, comprises a portable spray gun including a spray nozzle, means for applying a high potential to said nozzle, and means for supplying to said nozzle the liquid to be sprayed from a container of the liquid mounted on the spray gun. Examples of such electrostatic spraying apparatus are described in, inter alia, US-A-4356528.
  • the potential at the nozzle has to be maintained at above a certain minimum voltage, but should not be so high that corona discharge takes place.
  • the potential at the nozzle will need to be in an excess of 5 kV, and often above 10 kV, although the precise minimum value required will depend, inter alia, on the nozzle design.
  • the maximum voltage required is generally not more than 25 kV.
  • the magnitude and rapidity of the current changes in the primary determine the magnitude and shape of the high voltage pulses: the magnitude is restricted by the need to avoid excessive voltages at the nozzle which would give rise to corona discharge.
  • the rapid change of current in the transformer primary is conveniently achieved by periodically effecting the rapid discharge of a capacitor in the primary circuit through the transformer primary. Such rapid discharge may be effected by means of a triggering unit connected, in series with the transformer primary, across the primary circuit capacitor.
  • the triggering unit is arranged to discharge the primary circuit capacitor, via the transformer primary, typically through a thyristor or a gas gap discharge tube, when the voltage across the primary circuit capacitor, and hence across the triggering unit, reaches a predetermined value.
  • This rate of charging will of course depend on the capacitance of the primary circuit capacitor and the current supplied thereto.
  • the primary circuit capacitor will generally need to have a fairly large capacitance. Consequently to keep the current drain on the low voltage power source small, the charging rate of the primary circuit capacitor and hence the rate of actuation of the triggering device, and thus the frequency of the high voltage pulses must be relatively low.
  • the high voltage pulses are rectified and used to charge a capacitor in the high voltage circuit to maintain the required potential at the spray nozzle. If the capacitance of this capacitor in the high voltage circuit is sufficient, there will be little variation of the potential at the nozzle between pulses since the load represented by the transfer of charge at the nozzle to the liquid to effect electrostatic atomisation, together with leakage currents, will represent dissipation of only a small proportion of the charge on the capacitor.
  • the capacitor has a high capacitance
  • the high voltage circuit will have a high stored energy.
  • a high stored energy is undesirable as it may present safety hazards, for example electric shocks to the operator from accidental contact with the nozzle.
  • the stored energy is below 10 mJ.
  • the stored energy is given by where V is the voltage and C is the capacitance.
  • V is the voltage expressed in kilovolts, i.e. below 50 pF when the voltage is 20 kV.
  • the load current, represented by the transfer of charge to the liquid at the nozzle, required to effect atomisation is relatively small and, provided that the leakage currents are small, it would be possible to use a high voltage circuit having a stored energy below 10 mJ.
  • the charge dissipated as a result of the leakage currents represents a significant proportion of the charge on the capacitor with the result that, between the pulses applied to the capacitor, the voltage at the nozzle is liable to drop to below that required for spraying.
  • said generator being capable of producing said high voltage pulses of magnitude and frequency that the potential at said nozzle may be maintained at a sufficient value to cause electrostatic atomisation of the liquid but without corona discharge.
  • the lead from one side of the generator output to the nozzle in conjunction with a second lead connected to the other side of the generator output as the capacitor, sufficient capacitance can be obtained with negligible leakage current.
  • the two leads should be in sufficiently close proximity to give the requisite capacitance which is generally within the range (where V is in kV).
  • the capacitance is preferably within the range 10 to 50 pF.
  • two separate insulated wires each having a length of about 0.5 m may be twisted together as necessary to give the requisite capacitance.
  • the leads may of course be longer but spaced sufficiently far apart over some or all of their length that the capacitance is at the requisite level.
  • a suitable length of a twin core or coaxial capable may be employed.
  • the average potential at the nozzle will depend on the frequency and magnitude of the high voltage pulses applied to the capacitor: the magnitude is restricted by the need to avoid voltages that would give rise to corona discharge.
  • the frequency of the pulse is typically in the range 10-40 Hz, and preferably is in the range 15-30 Hz.
  • the requisite frequency will depend on the load applied by the liquid being sprayed which in turn will depend on the properties, e.g. resistivity, of the liquid and on the volumetric flow rate.
  • the latter is preferably below 0.25, particularly below 0.1 ml/s.
  • a rate of 0.05 ml/s typically represents a load of less than 100 nA.
  • the generator may be provided with means for varying the frequency and/or magnitude, i.e. peak voltage, of the high voltage pulses as the volumetric flow rate is varied.
  • the leakage current through the capacitor is virtually eliminated, leakage of charge from the capacitor will occur between pulses, inter alia, as a result of the reverse leakage current of the rectifier.
  • the rectifier reverse current may be significant in relation to the load presented by transfer of charge to the liquid being sprayed and will affect the minimum frequency required of the generator.
  • the spraying apparatus preferably comprises an elongated member intended to be held in the hand with the low voltage power supply, e.g. batteries, and high voltage generator in one end thereof with the spray nozzle at the other end.
  • the leads forming the high voltage circuit capacitor thus can extend along the elongated member to connect the nozzle to the generator.
  • one lead is connected to the nozzle while the other is connected to, or provides, an electrically conductive member adjacent to but spaced from the nozzle.
  • the capacitance between the nozzle and such an electrically conductive member should be taken into account.
  • the electrically conductive member is preferably maintained substantially at earth potential, for example by providing a connection to earth from that lead via the operator. Such an earthed electrically conductive member can then act as a field adjusting electrode as described in aforementioned US-A-4356528.
  • an elongated holder having the high voltage generator and a receptacle for receipt of the low voltage power source, e.g. batteries, at one end is provided, at the other end, with a receptacle for receipt of a canister of the liquid to be sprayed.
  • the nozzle may form part of the holder or may be attached to the canister. In the latter case means are provided in the holder for making electrical connection between the lead from the one side of the high voltage generator and the nozzle.
  • the apparatus is of particular utility for the spraying of liquids, such as pesticides, polishes, and the like at low volumetric flow rates.
  • the liquid preferably has a resistivity of 10 7 to loll ohm cm.
  • the liquid may be supplied to the spray nozzle by simple gravity feed.
  • This is disadvantageous in many cases since it restricts the spatial orientations of the nozzle that can be used.
  • This problem can be overcome by supplying the liquid to the nozzle from a pressurised container; in particular the liquid can be supplied from a container containing the liquid and a compressed pressurising agent.
  • the container is arranged so that the pressurising agent is not dispensed through the nozzle with the liquid to be sprayed. In this way the atomisation of the liquid by the electrostatic forces is not affected by the emergence of the pressurising agent.
  • the container comprises a barrier pack with the liquid to be sprayed contained within a collapsible inner container located within the outer container with the pressurising agent fluid in the space between the inner and outer containers.
  • the rate of delivery of the liquid to the spray nozzle will depend on the pressure exerted by the pressurising agent (which is often a gas at ambient temperatures and atmospheric pressure, but is liquid at the pressure prevailing within the container).
  • the pressure exerted by the pressurising agent is liable to considerable fluctuation as the ambient temperature varies, with the result that the liquid supply rate to the nozzle is also liable to considerable fluctuation: indeed over the range of ambient temperatures liable to be encountered in use of the spray gun, particularly where such use is outdoor, the pressure exerted by the pressurising agent, and consequently the flow rate, may vary in some cases, by a factor of four or more.
  • Variations in flow rate will affect the size, and size distribution, of the liquid droplets formed by electrostatic atomisation. Such variation in droplet size is undesirable for any given liquid there is an optimum droplet size, or size range, for the intended use of the liquid.
  • the present invention further provides, in electrostatic spraying apparatus of the type hereinbefore described for spraying a liquid as droplets from a nozzle supplied with said liquid from a pressurised container by applying a high voltage to said nozzle, the improvement comprising means to monitor the ambient temperature and to vary the average voltage applied to said nozzle in response to said monitored temperature to maintain the average droplet size within a predetermined range.
  • the average voltage at the spraying nozzle can be varied by variation of the amplitude, frequency and/or shape of the high voltage pulses. Such variations can be brought about by appropriate variation in the low voltage circuit, e.g. of the magnitude and/or frequency of the current changes in the transformer primary winding and/or the rate of change thereof.
  • the average high voltage applied to the nozzle can be varied.
  • a temperature sensitive electrical component e.g. a thermistor
  • the average nozzle voltages required to give a specified droplet size or size distribution at various flow rates of a given liquid can readily be determined by experiment. Typically for a given liquid at a given flow rate, an average voltage of 15 kV may be required at the nozzle. If the flow rate is increased by a factor of two, the average voltage required to obtain the same, or a similar, droplet size is typically increased to 20 kV.
  • the appropriate circuitry can be devised to provide the necessary variation in nozzle voltage to maintain the droplet size within the desired range.
  • the apparatus comprises an elongated member 1 having a handle portion 2 incorporating a trigger 3 and a sprayhead assembly 4 comprising a sleeve 5 in which a cartridge containing the liquid to be sprayed is inserted.
  • the cartridge has a mechanically actuated valve and a nozzle to which a high voltage can be applied.
  • the cartridge valve When the cartridge valve is open and a high voltage is applied to the nozzle, the liquid is electrostatically atomised as a spray through an orifice at the lever end of the sprayhead assembly 4.
  • an annular conductor 6 constituting a field intensifying electrode, e.g. as described in aforementioned US-A-4356528.
  • the shaft of the elongated member 1 comprises a casing formed by two shell mouldings of an electrically insulating material.
  • the sleeve 5 is moulded from an electrically insulating material and is of generally cylindrical configuration.
  • Sleeve 5 is located on the shell mouldings by means of an integrally moulded, open-sided, box structure 8 which engages with a hollow projection 9 on moulding 7 and a corresponding projection on the other shell moulding.
  • Sleeve 5 is provided with integrally moulded projections 10 in which one end 11 of a valve-actuating member 12 is pivotally mounted.
  • Sleeve 5 is also provided with an opening 13 through its wall, through which the other end 14 of the valve-actuating member 12 passes, and integral flanges 15, 16 which act as a guide for the end 14 of the valve-actuating member 12.
  • Screw mounted on the end of the sleeve 5 is a nose cone 17 having an opening 18 through which the end of the cartridge nozzle can project.
  • the cartridge 19 which is shown partly in section in Figure 2, is a metal can 20 provided with a closure 21 incorporating a valve assembly, typically of the type commonly employed in aerosol canisters. Inside can 20 a flexible bag 22 is mounted on the inlet 23 to the valve assembly. The liquid to be sprayed is contained within bag 22 while the space between bag 22 and the walls of the can 20 is charged with a volatile liquid pressurising agent, e.g. a fluorocarbon such as dichlorodifluoromethane.
  • the cartridge 19 also has a nozzle 24 having a fine bore (not shown) extending longitudinally therethrough. The nozzle 24 is formed integrally with a flange 25 forming part of the valve assembly.
  • Movement of flange 25 axially towards the base 26 of cartridge 19 effects opening of the valve to permit liquid to flow from the reservoir out of the cartridge via the fine bore extending through nozzle 24.
  • the bore is typically of 1 mm diameter while the tip of the nozzle 24 is typically of hemispherical configuration of 3-5 mm diameter.
  • Cartridge 19 is held in place by a rib 27 on a cap 28 engaging with the base 26 of the cartridge and holding the flange 25 against the valve actuating member 12.
  • the cap 28 is moulded from an electrically insulating plastics material and is pivotally mounted in a boss 29 in shell mould 7 and a corresponding boss in the other shell mould.
  • Cap 28 has an integral latch 30 engaging with a projection 31 moulded integrally with sleeve 5.
  • a spring metal contact strip 33 Extending through an opening 32 in sleeve 5 is a spring metal contact strip 33 which is held in place between the shell mouldings and the wall of sleeve 5. Electrically connected, e.g. soldered, to strip 33 is a high voltage lead 34 from a generator located in the handle portion of the apparatus. On application of a high voltage to lead 34, the high voltage is applied, via contact strip 32, to the metal can cartridge 19 and hence, via conduction through the cartridge and its contents, to the nozzle 24.
  • the valve-actuating member 12 is a moulding of an electrically insulating plastics material of such cross section that the portion in the vicinity of nozzle 24, flange 25, and mounting 10 is relatively rigid but the free end 14 is relatively flexible.
  • the valve-actuating member 12 is provided with an opening 35 through which nozzle 24 projects, and projections 36 which engage with flange 25 on either side of nozzle 24. It is then seen that longitudinal movement of the free end 14 of the valve-actuating member 12 away from mounting 10 causes flange 25 to be depressed thus opening the valve.
  • the free end 14 of the valve-actuating member 12 is provided with a slot 37 which engages with a hook 38 of a metal wire 39 which extends along the shaft of the elongated member to the trigger 3.
  • a metal wire 6 acting as a field adjusting electrode.
  • a flexible extension 40 of wire 6 passes through a groove (shown dotted in Figure 2) in shell moulding 7 and is electrically connected, e.g. soldered, to wire 39.
  • Wires 39 and 40 thus provide an electrical connection from the trigger 3 to the field adjusting electrode 6 and wire 39 also provides a mechanical connection from trigger 3 to the valve actuating member 12.
  • the handle portion 2 of the apparatus is shown in Figure 3.
  • the generator assembly comprises a printed circuit board 45 on which are mounted the various components shown in Figure 4 as enclosed within the dotted box. For simplicity these components are not shown in Figure 3.
  • Board 45 is mounted in a moulding 46 of electrically insulating plastics material.
  • Also mounted in moulding 46 is an output step-up transformer 47 which is connected to board 45 by leads 48, 49.
  • the high voltage output from transformer 47 is fed, via a high voltage diode 50, (not shown in Figure 3), to the high voltage lead 34 via a contact within sleeve 51 attached to transformer 47.
  • the generator assembly 43 is located by projections 52, 53, 54 and 55 integral with shell moulding 7 and by corresponding projections (not shown) in the other shell moulding.
  • Board 45 is provided with two electrical contacts 56, 57.
  • Contact 56 is a spring metal strip which extends round moulding 46 to the trigger assembly 44 while contact 57 projects into the battery compartment 41 wherein it contacts the positive terminal of the train of batteries 42.
  • Extending the length of compartment 41 is a wire 58.
  • wire 58 is formed as a coil spring contact 59 which urges the trains of batteries 42 into engagement with contact 57.
  • Wire 58 also serves to connect the negative contact of the battery train to the trigger assembly 44.
  • the trigger assembly 44 comprises a trigger lever 3 made of an electrically conductive plastics material pivotably mounted on bosses 60 in the shell mouldings.
  • the free end of wire 58 from the battery compartment extends through a hole in lever 3 to form a contact pin 61.
  • a pin 62 mounted in lever 3 is a pin 62 formed from an electrically insulating material. Pin 62 engages with the spring contact strip 56 from board 45 to hold the strip 56 out of engagement with pin 61 when the trigger lever 3 is in the "off” position.
  • Strip contact 56 is laterally spaced from lever 3, and hence insulated therefrom when the trigger is in the "off” position. Rotation of lever 3 from the "off” position causes the contact pin 61 to engage with strip contact 36 thus completing the circuit to supply power from the batteries 42 to the generator.
  • Hooked round an integral extension 63 to trigger lever 3 is the connecting wire 39.
  • a return spring (not shown) is provided to bias lever 3 to the "off" position.
  • the low voltage part of the high voltage generator circuit consists of a conventional transistorised saturation oscillator formed by the primary 64 of a first step-up transformer 65, resistor 66 and a transistor 67. Typically this oscillator has a frequency of the order of 10 to 100 kHz.
  • the secondary of transformer 65 is connected, via a diode 68, to a capacitor 69.
  • a gas-gap discharge tube 70 connected in series with the primary of the output step-up transformer 47. Shown dotted in the high voltage output circuit of Figure 4 is a capacitor 71.
  • This capacitor is not a discrete component but represents the capacitance between the high voltage lead 34, the cartridge 19, and the nozzle 24 and the adjacent "earthed" components, e.g. wires 39 and 40, and the field intensifying electrode 6.
  • guides may be provided in the shell mouldings to hold wire 39 in the desired spatial relationship to the high voltage lead 34.
  • the saturation oscillator gives rise to current pulses in the secondary of transformer 65 which charge capacitor 69 via diode 68.
  • the voltage across capacitor 69 reaches the striking voltage of gas-gap discharge tube 70, the latter conducts, discharging capacitor 69 through the primary of output transformer 47, until the voltage across the gas-gap discharge tube falls to the extinguishing voltage.
  • the striking voltage is 150-250 V and the extinguishing voltage is less than 10 V.
  • capacitor 69 The discharge of capacitor 69 through the primary of transformer 47 produces high voltage pulses in the secondary thereof: these high voltage pulses charge capacitor 71 via diode 50 and thus maintain a sufficiently high potential between nozzle 24 and the field intensifying electrode 6 for electrostatic atomisation of the liquid from nozzle 24.
  • the frequency with which thehigh voltage pulses are produced is determined by the value of capacitor 69, the impedance of the secondary of transformer 65 and the magnitude and frequency of the pulses produced by the saturation oscillator.
  • a pesticide composition of resistivity 8x10 7 ohm cm was sprayed from apparatus of the type shown in Figures 1 to 4.
  • the voltage at nozzle 24 was about 18 kV, the liquid flow rate 1 ml/min, the frequency of the high voltage pulses about 25 Hz.
  • the capacitance of capacitor 71 was about 20 pF and primarily formed by the capacitance between wires 34 and 39 which were each about 0.9 m long and spaced apart by an average of about 2 cm.
  • the series train of batteries 42 gave a voltage of 3.1 V and the current drain thereon was about 150 mA.
  • the arrangement of the generator is modified by the replacement of the gas-gap discharge tube 70 by a thyristor 72 and by the incorporation of a temperature dependent triggering circuit 73, the output of which is applied to the gate of thyristor 72.
  • This temperature dependent triggering circuit incorporates a temperature sensitive component, e.g. a thermistor, and is arranged such that as the temperature increases, thyristor 72 is triggered to conduct, thus discharging capacitor 69 through the primary of output transformer 47, at increasing voltages across capacitor 69. Although this results in a reduction of the frequency of discharge of capacitor 69, the rate of transfer of energy to the high voltage circuit is increased thus giving an increased voltage at the nozzle 24.
  • a temperature sensitive component e.g. a thermistor
  • the pressure exerted by the volatile liquid in can 20 increases, thus increasing the liquid flow rate through nozzle 24.
  • the characteristic of the temperature dependent triggering circuit 73 is arranged so that the voltage at the nozzle 24 is increased, as the flow rate through nozzle 24 increases, so as to give the desired droplet size spectrum.

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  • Electrostatic Spraying Apparatus (AREA)

Claims (11)

1. Appareil portatif de pulvérisation électrostatique comprenant:
(a) un ajutage de pulvérisation (24),
(b) des moyens d'amenée de liquide à pulvériser audit ajutage,
(c) une source d'alimentation à basse tension (42),
(d) un générateur à haute tension (43) alimenté par la dite source à basse tension, de sorte que des impulsions à haute tension redressée peuvent être produites à sa sortie,
(e) un condensateur (71) raccordé à l'ajutage et à un premier côté de la sortie du générateur, de sorte que ce condensateur peut être chargé par les impulsions à haute tension redressées afin de maintenir l'ajutage à un potentiel suffisament élevé, par rapport à l'autre côté de la sortie du générateur, pour provoquer la pulvérisation électrostatique du liquide à l'ajutage, caractérisé en ce que le condensateur (71) a une valeur inférieure à
Figure imgb0013
V étant la tension moyenne, exprimée en kilovolts, que le générateur est capable de maintenir à l'ajutage, et en ce que le condensateur est constitué par la capacité entre un conducteur (34, 19) reliant ledit premier côté de la sortie de générateur à l'ajutage (24) et un conducteur (39, 40) connecté à l'autre côté de la sortie de générateur,
le générateur (43) étant capable de produire les dites impulsions à haute tension d'une grandeur et d'une fréquence telles que le potentiel à l'ajutage peut être maintenu à une valeur suffisante pour provoquer la pulvérisation électrostatique du liquide mais sans décharge d'effluve.
2. Appareil suivant la revendication 1, dans lequel le condensateur (71) a une valeur supérieure à
Figure imgb0014
3. Appareil suivant la revendication ou la revendication 2, dans lequel le condensateur (71) a une valeur comprise entre 10 et 50 pF.
4. Appareil suivant l'une quelconque des revendications 1 à 3, dans lequel le générateur (43) est capable de maintenir une tension comprise entre 10 et 25 kilovolts à l'ajutage (24).
5. Appareil suivant l'une quelconque des revendications 1 à 4, dans lequel les impulsions à haute tension sont redressées dans le générateur (43) par une diode (50) ayant un courant de fuite inférieur à 1 µA, à 37 kV et 20°C.
6. Appareil suivant l'une quelconque des revendications 1 à 5, dans leque le générateur (43) comprend un condensateur (69) qui peut être déchargé à travers le primaire d'un transformateur élévateur (47) par l'intermédiaire d'un dispositif de déclenchement (70), de sorte que la décharge du condensateur (69) à travers le primaire produit des impulsions à haute tension dans le secondaire dudit transformateur.
7. Appareil suivant l'une quelconque des revendications 1 à 6, dans lequel le générateur (43) produit les impulsions à haute tension à une fréquence inférieure à 50 Hz.
8. Appareil suivant l'une quelconque des revendications 1 à 7, dans lequel un élément électriquement conducteur (6) est placé en position adjacente mais espacée de l'ajutage (24) et raccordé audit autre côté de la sortie du générateur, et ledit condensateur de valeur inférieure à
Figure imgb0015
est constitué par le conducteur (34, 19) reliant ledit premier côté de la sortie du générateur à l'ajutage et par le conducteur (39, 40) reliant le dit autre côté de la sortie du générateur audit élément électriquement conducteur.
9. Appareil suivant l'une quelconque des revendications 1 à 8, dans lequel les moyens d'amenée de liquide à l'ajutage de pulvérisation comprennent une valve (21) manoeuvrée mécaniquement, actionnée par une gâchette (3) éloignée de ladite valve, et le condensateur de valeur inférieure à
Figure imgb0016
est constitué par le conducteur (34, 19) reliant ledit premier côté de la sortie du générateur (43) à l'ajutage et un élément électriquement conducteur (6) faisant partie de la liaison mécanique de la gâchette à la valve, ledit élément électriquement conducteur étant relié électriquement audit autre côté de la sortie du générateur.
10. Appareil suivant l'une quelconque des revendications 1 à 9, dans lequel les moyens d'amenée du liquide à l'ajutage comprennent un récipient sous pression (20), et des moyens (73) sont prévus pour mesurer la température ambiante et modifier la tension moyenne appliquée à l'ajutage en réponse à ladite température mesurée, de manière à maintenir la dimension moyenne de gouttelette du liquide pulvérisé par l'ajutage à l'intérieur d'une plage prédéterminée.
EP84304256A 1983-07-15 1984-06-22 Pulvérisation électrostatique Expired EP0132062B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB838319225A GB8319225D0 (en) 1983-07-15 1983-07-15 Electrostatic spraying
GB8319225 1983-07-15
GB838319226A GB8319226D0 (en) 1983-07-15 1983-07-15 Electrostatic spraying
GB8319226 1983-07-15

Publications (2)

Publication Number Publication Date
EP0132062A1 EP0132062A1 (fr) 1985-01-23
EP0132062B1 true EP0132062B1 (fr) 1986-11-20

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EP84304256A Expired EP0132062B1 (fr) 1983-07-15 1984-06-22 Pulvérisation électrostatique

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EP (1) EP0132062B1 (fr)
AU (1) AU3035384A (fr)
CA (1) CA1220335A (fr)
DE (1) DE3461353D1 (fr)
DK (1) DK346684A (fr)
GB (1) GB8415981D0 (fr)
NO (1) NO842849L (fr)
NZ (1) NZ208684A (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8410520D0 (en) * 1984-04-25 1984-05-31 Ici Plc Electrostatic spraying apparatus
GB8410519D0 (en) * 1984-04-25 1984-05-31 Ici Plc Spraying apparatus
GB9115276D0 (en) * 1991-07-15 1991-08-28 Unilever Plc Skin treatment system
GB9115275D0 (en) * 1991-07-15 1991-08-28 Unilever Plc Colour cosmetic spray system
GB9115278D0 (en) * 1991-07-15 1991-08-28 Unilever Plc Liquid spraying apparatus and method

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3212211A (en) * 1963-06-21 1965-10-19 Martha W Chapman Insecticidal application device
IE45426B1 (en) * 1976-07-15 1982-08-25 Ici Ltd Atomisation of liquids
US4165022A (en) * 1977-03-02 1979-08-21 Ransburg Corporation Hand-held coating-dispensing apparatus
US4323947A (en) * 1979-08-13 1982-04-06 J. Wagner Ag. Electrostatic gun with improved diode-capacitor multiplier

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Publication number Publication date
DE3461353D1 (en) 1987-01-08
GB8415981D0 (en) 1984-07-25
NZ208684A (en) 1986-12-05
CA1220335A (fr) 1987-04-14
DK346684A (da) 1985-01-16
NO842849L (no) 1985-01-16
AU3035384A (en) 1985-01-17
EP0132062A1 (fr) 1985-01-23
DK346684D0 (da) 1984-07-13

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