CA1220335A - Electrostatic spraying - Google Patents
Electrostatic sprayingInfo
- Publication number
- CA1220335A CA1220335A CA000458271A CA458271A CA1220335A CA 1220335 A CA1220335 A CA 1220335A CA 000458271 A CA000458271 A CA 000458271A CA 458271 A CA458271 A CA 458271A CA 1220335 A CA1220335 A CA 1220335A
- Authority
- CA
- Canada
- 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
Links
Classifications
-
- 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
Landscapes
- Electrostatic Spraying Apparatus (AREA)
Abstract
Abstract Electrostatic spraying Portable electrostatic spraying apparatus having a low stored energy wherein the capacitor of the high voltage circuit is formed by the capacitance between a lead connecting the high voltage generator output to the spray nozzle and a lead connected to the other side of the generator output.
Description
~201~3~;
ectrostatic Spraying hi eQtion relates to electrostatic ping. ye form of electrostatic spraying apparatus, for example for agricultural or horticulture use, comprises a portable spray gun including a spray nozzle means for applying a high potential to said nozzle, and mean for supplying to said nozzle the liquid -to be sprayed from a container of the liquid mounter on the spray guy. Examples of such electron station spraying apparatus are described in, inter alias ~S-~-4356528.
It has been proposed Lo U~P-A-3212211 to produce the Nazis Mary high voltage for a portable electrostatic spraying device from a low voltage power supply, e.g. batteries, by means of a high volt-age generator producing rectified high voltage pulses which charge a capacitor connected across the generator -output The charge on the capacitor is used to maintain the requisite potential at the prune nozzle.
Clearly, to obtain electrostatic atomization 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. Gffner-all, to effect electrostatic atomization, the potent 1 at the nozzle will need to be in an excess of 5 TV, and often above 10 I although the precise minimum value required will depend, inter alias ox the nozzle design. Ike maximum voltage required is generally jot more than 25 TV
In low cost generators it it generally necessary to employ a switching System Lo the generator which produces rapid if`
~2~335
ectrostatic Spraying hi eQtion relates to electrostatic ping. ye form of electrostatic spraying apparatus, for example for agricultural or horticulture use, comprises a portable spray gun including a spray nozzle means for applying a high potential to said nozzle, and mean for supplying to said nozzle the liquid -to be sprayed from a container of the liquid mounter on the spray guy. Examples of such electron station spraying apparatus are described in, inter alias ~S-~-4356528.
It has been proposed Lo U~P-A-3212211 to produce the Nazis Mary high voltage for a portable electrostatic spraying device from a low voltage power supply, e.g. batteries, by means of a high volt-age generator producing rectified high voltage pulses which charge a capacitor connected across the generator -output The charge on the capacitor is used to maintain the requisite potential at the prune nozzle.
Clearly, to obtain electrostatic atomization 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. Gffner-all, to effect electrostatic atomization, the potent 1 at the nozzle will need to be in an excess of 5 TV, and often above 10 I although the precise minimum value required will depend, inter alias ox the nozzle design. Ike maximum voltage required is generally jot more than 25 TV
In low cost generators it it generally necessary to employ a switching System Lo the generator which produces rapid if`
~2~335
2 32802 changes of current in the primal of a step-up transformer, 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 Lo the primary circuit through the transformer primary.
Such rapid discharge may be effected by means of a triggering unit lo connecters in series with the transformer primary, across the primary circuit capacitor The triggering unit is cringed to discharge the primary circuit capacitor, via the transformer primary, typically through a thruster or a gas gap discharge tube, when the voltage across the primary circuit capacitor, and hence across the triggering unit, reaches a predetermined value.
the frequency of operation of the triggering unit and hence the frequency with which the high voltage pulses are goner-axed, thus depends on the rate of charging of the primary circuit capacitor.
this rate of charging will of course depend on the capacitance of the primary circuit capacitor and the current supplied thereto. In order to obtain high voltage pulses of adequate magnitude to achieve the desired nozzle potential under load, the primary circuit capacitor will generally need to have a fairly large capacitance. Consequently to keep the current drake 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.
As mentioned herein before, 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 Jo ~2~335
Such rapid discharge may be effected by means of a triggering unit lo connecters in series with the transformer primary, across the primary circuit capacitor The triggering unit is cringed to discharge the primary circuit capacitor, via the transformer primary, typically through a thruster or a gas gap discharge tube, when the voltage across the primary circuit capacitor, and hence across the triggering unit, reaches a predetermined value.
the frequency of operation of the triggering unit and hence the frequency with which the high voltage pulses are goner-axed, thus depends on the rate of charging of the primary circuit capacitor.
this rate of charging will of course depend on the capacitance of the primary circuit capacitor and the current supplied thereto. In order to obtain high voltage pulses of adequate magnitude to achieve the desired nozzle potential under load, the primary circuit capacitor will generally need to have a fairly large capacitance. Consequently to keep the current drake 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.
As mentioned herein before, 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 Jo ~2~335
3 32802 transfer of charge at the nozzle to the liquid to effect electron static atomization, together Ruth leakage currents, trill represent dissipation of only a small proportion of the charge on the capacitor.
However, if 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 satiety hazards, for example electric shocks to the operator from accidental con-tact with the nuzzle Desirably the stored energy is below 10 mJ0 The stored energy is given by C2V where V is the voltage and C
is the capacitance. Hence to achieve a stored energy below 10 my the capacitance must be below 2 v21 pi where V is the voltage expressed in kilovolts, ire. below 50 pi Then the voltage is 20 TV
The load current, represented by the transfer of charge to the liquid at the nozzle, required to effect atomization 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 my.
However, not only are capacitors capable of operation at high voltages expensive, but, even those capacitors of the relatively WOW capacitance required, exhibit considerable leakage currents at such high voltages.
t these relatively low values of capacitance the charge dissipated as a result of the leakage currents represents a signify-cant proportion of the charge on the capacitor with the result that between the pulses applied to the capacitor the voltage at the no ale is liable to drop to below that required for spurring While this could be counteracted by increasing the frequency of the high voltage pulses applied to the capacitor in the high voltage circuit, as explained herein before, increasing -the frequency results in an increase in the current drawn on the power supply. Consequently to maintain the current drain at an acceptable level, e.g. to give an adequate life where dry batteries are employed as the low voltage power source, the frequency with which the pulses can be applied to the high voltage capacitor is 335i
However, if 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 satiety hazards, for example electric shocks to the operator from accidental con-tact with the nuzzle Desirably the stored energy is below 10 mJ0 The stored energy is given by C2V where V is the voltage and C
is the capacitance. Hence to achieve a stored energy below 10 my the capacitance must be below 2 v21 pi where V is the voltage expressed in kilovolts, ire. below 50 pi Then the voltage is 20 TV
The load current, represented by the transfer of charge to the liquid at the nozzle, required to effect atomization 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 my.
However, not only are capacitors capable of operation at high voltages expensive, but, even those capacitors of the relatively WOW capacitance required, exhibit considerable leakage currents at such high voltages.
t these relatively low values of capacitance the charge dissipated as a result of the leakage currents represents a signify-cant proportion of the charge on the capacitor with the result that between the pulses applied to the capacitor the voltage at the no ale is liable to drop to below that required for spurring While this could be counteracted by increasing the frequency of the high voltage pulses applied to the capacitor in the high voltage circuit, as explained herein before, increasing -the frequency results in an increase in the current drawn on the power supply. Consequently to maintain the current drain at an acceptable level, e.g. to give an adequate life where dry batteries are employed as the low voltage power source, the frequency with which the pulses can be applied to the high voltage capacitor is 335i
4 32802 limited, generally to below about 50 Ho.
We have now devised an arrangement, having a low stored energy high voltage circuit, that can be operated at a frequency that gives an acceptable current drain on the power source.
According to the present invention we provide a portable electrostatic spraying apparatus including (a) a spray nozzle, - (b) means to supply liquid to be sprayed to said spray nozzle, 10 (c) a low voltage power source, (d) a high voltage generator powered by said low voltage power source, whereby rectified high voltage pulses may be produced across its output, (e) a capacitor connected to said nozzle and to one side of said generator output whereby said capacitor may be charged by said rectified high voltage pulses so that said nozzle may be maintained at a sufficiently high potential, with respect to the other side of said generator output, to cause electrostatic atoms-anion of said liquid at said nozzle, characterized in that capacitor has a value below pi, where V is the average voltage, expressed in kilovolts, that said generator is capable of maintaining at said nozzle, and in that said capacitor is formed by the capacitance between a lead coy-netting said one side of the generator output to said nozzle and a lead connected to said other side of the generator output, said generator being capable of producing said high voltage pulses of such magnitude and frequency that the potential at said nozzle may be maintained at a sufficient value to cause electrostatic atomization of the liquid but without corona disk charge.
the use of the lead from one side of the generator output to tune nozzle, in conjunction with a second lead connected to the other side of the generator output as the capacitor surf-fishnet capacitance can be obtained with negligible leakage 3~5 3~802 current. the two leads should be in sufficiently close proximity to give the requisite capacitance which is generally within the range Z X2lo to F Pi (where V is in TV).
We have now devised an arrangement, having a low stored energy high voltage circuit, that can be operated at a frequency that gives an acceptable current drain on the power source.
According to the present invention we provide a portable electrostatic spraying apparatus including (a) a spray nozzle, - (b) means to supply liquid to be sprayed to said spray nozzle, 10 (c) a low voltage power source, (d) a high voltage generator powered by said low voltage power source, whereby rectified high voltage pulses may be produced across its output, (e) a capacitor connected to said nozzle and to one side of said generator output whereby said capacitor may be charged by said rectified high voltage pulses so that said nozzle may be maintained at a sufficiently high potential, with respect to the other side of said generator output, to cause electrostatic atoms-anion of said liquid at said nozzle, characterized in that capacitor has a value below pi, where V is the average voltage, expressed in kilovolts, that said generator is capable of maintaining at said nozzle, and in that said capacitor is formed by the capacitance between a lead coy-netting said one side of the generator output to said nozzle and a lead connected to said other side of the generator output, said generator being capable of producing said high voltage pulses of such magnitude and frequency that the potential at said nozzle may be maintained at a sufficient value to cause electrostatic atomization of the liquid but without corona disk charge.
the use of the lead from one side of the generator output to tune nozzle, in conjunction with a second lead connected to the other side of the generator output as the capacitor surf-fishnet capacitance can be obtained with negligible leakage 3~5 3~802 current. the two leads should be in sufficiently close proximity to give the requisite capacitance which is generally within the range Z X2lo to F Pi (where V is in TV).
5 the capacitance is preferably within the range 10 to 50pFo For example 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. Alternatively a suitable length of a twin core or Cole cable Jay be employed.
Since a capacitor formed by two such leads will give negligible leakage current, the leakage current between pulses will be markedly reduced, enabling sufficient potential to be maintained at the nozzle As mentioned herein before 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 no-striated by the need to avoid voltages that would give rise to corona discharge The frequency of the pulses is typically in the range 10 - 40 Ho, and preferably is in the range it - 30 Ho the requisite frequency will depend ox the load applied by the liquid being sprayed which in turn will depend on the properties, ego resistivity, of the liquid and on the volumetric flow rate.
the latter is preferably below 0025, particularly below 0.1 ml/s.
rate ox 0.05 ml/s typically represents a load of less than 100 nay If desired the generator may be provided with means for varying the frequency Audrey magnitude, Leo peak voltage, of the high voltage pulses as the volumetric flow rate is varied.
though, as a result of using the leads from the high voltage generator to form the capacitor, the leakage cur-rent through the capacitor is virtually eliminated, leakage of charge from the capacitor will occur between pulses, inter alias I
Since a capacitor formed by two such leads will give negligible leakage current, the leakage current between pulses will be markedly reduced, enabling sufficient potential to be maintained at the nozzle As mentioned herein before 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 no-striated by the need to avoid voltages that would give rise to corona discharge The frequency of the pulses is typically in the range 10 - 40 Ho, and preferably is in the range it - 30 Ho the requisite frequency will depend ox the load applied by the liquid being sprayed which in turn will depend on the properties, ego resistivity, of the liquid and on the volumetric flow rate.
the latter is preferably below 0025, particularly below 0.1 ml/s.
rate ox 0.05 ml/s typically represents a load of less than 100 nay If desired the generator may be provided with means for varying the frequency Audrey magnitude, Leo peak voltage, of the high voltage pulses as the volumetric flow rate is varied.
though, as a result of using the leads from the high voltage generator to form the capacitor, the leakage cur-rent through the capacitor is virtually eliminated, leakage of charge from the capacitor will occur between pulses, inter alias I
6 32802 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. We prefer to employ as the rectifier a high voltage diode rated at a leakage current of less than l at 37 TV at 20C. Such a diode will have a reverse leakage current of less than about lo no at 20 TV at 20C~
the spraying apparatus preferably comprises an elongated member intended to be held in the hand with the low voltage power supply, ego batteries, cud 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 In a preferred arrangement one lead is connected to the nozzle while the other is connected to, orprcvides, an electrically conductive member adjacent to but spaced from the nozzle. In assessing the lead capacitance, the capacitance between the nozzle and such an electrically conductive member should be taken into accost The electrically conductive member is preferably main-twined substantially at earth potential, for example by proving 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 SUE
In one form of the apparatus on elongated holder having the high voltage generator and a receptacle for receipt of the low voltage power source, erg. batteries, at ore 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 huller or may be attached to the canister In the latter case meats 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 spray-in of liquids, such as pesticides, polishes, and the like at low ,~22~
the spraying apparatus preferably comprises an elongated member intended to be held in the hand with the low voltage power supply, ego batteries, cud 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 In a preferred arrangement one lead is connected to the nozzle while the other is connected to, orprcvides, an electrically conductive member adjacent to but spaced from the nozzle. In assessing the lead capacitance, the capacitance between the nozzle and such an electrically conductive member should be taken into accost The electrically conductive member is preferably main-twined substantially at earth potential, for example by proving 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 SUE
In one form of the apparatus on elongated holder having the high voltage generator and a receptacle for receipt of the low voltage power source, erg. batteries, at ore 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 huller or may be attached to the canister In the latter case meats 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 spray-in of liquids, such as pesticides, polishes, and the like at low ,~22~
7 3 32802 volumetric flow rates The liquid preferably has a resisti~Jity of 107 to 1011 ohm. cm.
The liquid may be supplied to the spray nozzle by simple gravity feed. However this is disadvantageous in many cases since it restricts the spatial orientations of the nozzle that can be used Tins problem can be overcome by supplying the liquid to the nozzle from a pressurized container; in particular the liquid can be supplied from a container containing the liquid and a compressed pressurizing agent.
It is preferred that the container is arranged so that the pressuring agent is not dispensed through the nozzle with the liquid to be sprayed. In this way the atomization of the liquid by the electrostatic forces is not affected by the emergence of the pressurizing agent In one preferred arrangement the count inter comprises a barrier pack with the liquid to be sprayed contained within a collapsible inner container located within the outer container with the pressurizing 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 pressurizing agent (which is often a gas at ambient temperatures and atmospheric pressure, but is liquid at the pressure prevailing within the container). We have found that the pressure exerted by the pros-surmising 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 o'er the range of ambient temperatures liable to be encountered in use ox the spray gun particularly where such use is outdoor, the pressure exerted by the pros-surmising agent, and consequently the flow rate, may vary, insole 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 elect static atomization Such variation in droplet size is undesir-able since for an joy liquid there is an optimum droplet size I
The liquid may be supplied to the spray nozzle by simple gravity feed. However this is disadvantageous in many cases since it restricts the spatial orientations of the nozzle that can be used Tins problem can be overcome by supplying the liquid to the nozzle from a pressurized container; in particular the liquid can be supplied from a container containing the liquid and a compressed pressurizing agent.
It is preferred that the container is arranged so that the pressuring agent is not dispensed through the nozzle with the liquid to be sprayed. In this way the atomization of the liquid by the electrostatic forces is not affected by the emergence of the pressurizing agent In one preferred arrangement the count inter comprises a barrier pack with the liquid to be sprayed contained within a collapsible inner container located within the outer container with the pressurizing 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 pressurizing agent (which is often a gas at ambient temperatures and atmospheric pressure, but is liquid at the pressure prevailing within the container). We have found that the pressure exerted by the pros-surmising 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 o'er the range of ambient temperatures liable to be encountered in use ox the spray gun particularly where such use is outdoor, the pressure exerted by the pros-surmising agent, and consequently the flow rate, may vary, insole 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 elect static atomization Such variation in droplet size is undesir-able since for an joy liquid there is an optimum droplet size I
8 3 32802 or size range, for the intended use of the liquid.
or example, when spraying plants with a pesticide formulation, if the droplets are too large, the amount of "wrap-round", giving coating on the underside of plant leaves, is reduced; whereas if the droplets are too small, they are liable to be unduly affected by factors such as wind strength and so may drift onto plants other than those intended and/or on to the operator As a further feature of the invention we have devised a way of overcoming these difficulties by varying the nozzle potential to control the droplet size Accordingly the present invention further provides, in electrostatic spraying apparatus of the type herein before described for spraying a liquid as droplets from a nozzle sup-plied with said liquid from a pressurized container by applying high voltage to said nozzle, the improvement comprising means to monitor the ambient temperature and to vary the average volt-age applied to said nozzle in response to said monitored temper azure to maintain the average droplet size within a predetermined range.
he 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, ego of the magnitude and/or frequency of the current changes in the transformer primary winding and/or the rate of change thereof.
y incorporating a temperature sensitive electrical component, e.g. a thermistor, into the spray apparatus and using the variation in the electrical properties of this component with temperature to modify the transformer primary current changes, the average high voltage applied to the nozzle can be varied.
he average nozzle voltages required to give a specified droplet size or size distribution at various flow rates of a given liquid can readily be diatom by e~perimenta Typically for a
or example, when spraying plants with a pesticide formulation, if the droplets are too large, the amount of "wrap-round", giving coating on the underside of plant leaves, is reduced; whereas if the droplets are too small, they are liable to be unduly affected by factors such as wind strength and so may drift onto plants other than those intended and/or on to the operator As a further feature of the invention we have devised a way of overcoming these difficulties by varying the nozzle potential to control the droplet size Accordingly the present invention further provides, in electrostatic spraying apparatus of the type herein before described for spraying a liquid as droplets from a nozzle sup-plied with said liquid from a pressurized container by applying high voltage to said nozzle, the improvement comprising means to monitor the ambient temperature and to vary the average volt-age applied to said nozzle in response to said monitored temper azure to maintain the average droplet size within a predetermined range.
he 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, ego of the magnitude and/or frequency of the current changes in the transformer primary winding and/or the rate of change thereof.
y incorporating a temperature sensitive electrical component, e.g. a thermistor, into the spray apparatus and using the variation in the electrical properties of this component with temperature to modify the transformer primary current changes, the average high voltage applied to the nozzle can be varied.
he average nozzle voltages required to give a specified droplet size or size distribution at various flow rates of a given liquid can readily be diatom by e~perimenta Typically for a
9 32802 given liquid at a given flow rate, an average voltage of 15 TV
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 kVo Likewise variation in pressurizing agent pressure, and hence liquid flow rate, with temperature can also be readily determined.
From this data, and from the temperature characteristics of the temperature sensitive component, the appropriate circuitry can be devised to provide the necessary variation in nozzle volt-age to maintain the droplet size within the desired range.
The invention it illustrated by reference to the accompanying drawings wherein:
Figure 1 is an elevation of one form of the apparatus, Figure 2 is a longitudinal section of the spurred part of the apparatus, Figure 3 is a longitudinal section of -the handle part of the apparatus Figure 4 is a circuit diagram, Figure 5 shows a modification of part of the circuit depicted in figure I
Referring first to Figure 1, the apparatus comprises an elongated member 1 having a handle portion 2 incorporating a trigger 3 and a spurred 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 When the cartridge valve is open Ed a high voltage is applied to the nozzle, the liquid is electrostatically atomized a a spray through an orifice at the lever end of the spurred assembly I Jo enhance the spray there is disposed around the sleeve 5, but insulated from the nozzle, an Allah æ conductor 6 constituting a field intensifying electrode ego as described in aforementioned ASP 4356528.
the shaft of the elongated member 1 comprises a casing ~2~35 32~02 formed by two shell moldings of an electrically insulating material.
Referring now -to Figure 2 one of the shell moldings is indicated by reference numeral 7. The sleeve 5 is mounded prom an electrically insulating material and is of generally cylindrical configuration. Sleeve 5 is located on the shell moldings by means of an integrally mounded, open-sided, box structure 8 which engages with a hollow projection 9 on mound-in 7 and a corresponding projection on the other shell mound in. Sleeve 5 is provided with integrally mounded projections
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 kVo Likewise variation in pressurizing agent pressure, and hence liquid flow rate, with temperature can also be readily determined.
From this data, and from the temperature characteristics of the temperature sensitive component, the appropriate circuitry can be devised to provide the necessary variation in nozzle volt-age to maintain the droplet size within the desired range.
The invention it illustrated by reference to the accompanying drawings wherein:
Figure 1 is an elevation of one form of the apparatus, Figure 2 is a longitudinal section of the spurred part of the apparatus, Figure 3 is a longitudinal section of -the handle part of the apparatus Figure 4 is a circuit diagram, Figure 5 shows a modification of part of the circuit depicted in figure I
Referring first to Figure 1, the apparatus comprises an elongated member 1 having a handle portion 2 incorporating a trigger 3 and a spurred 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 When the cartridge valve is open Ed a high voltage is applied to the nozzle, the liquid is electrostatically atomized a a spray through an orifice at the lever end of the spurred assembly I Jo enhance the spray there is disposed around the sleeve 5, but insulated from the nozzle, an Allah æ conductor 6 constituting a field intensifying electrode ego as described in aforementioned ASP 4356528.
the shaft of the elongated member 1 comprises a casing ~2~35 32~02 formed by two shell moldings of an electrically insulating material.
Referring now -to Figure 2 one of the shell moldings is indicated by reference numeral 7. The sleeve 5 is mounded prom an electrically insulating material and is of generally cylindrical configuration. Sleeve 5 is located on the shell moldings by means of an integrally mounded, open-sided, box structure 8 which engages with a hollow projection 9 on mound-in 7 and a corresponding projection on the other shell mound in. Sleeve 5 is provided with integrally mounded projections
10 in tush one end 11 of a v~Jve-actuating member 12 is pivot-ally mounted.
Sleeve 5 is also provided with an opening 13 through its wall, through which the other end 14 of the valve-actuating 15 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 cart-ridge 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 in-corporating 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 pressurizing agent, ego a fluorocarbon such as dichloro-difluoromethane. the cartridge 19 also has a nozzle 24 having a fine bore (not shown) extending longitudinally there through.
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 extend through nozzle 24. the bore is typically of 1 my diameter while the tip of the nozzle 24 is , Lo 33~
Sleeve 5 is also provided with an opening 13 through its wall, through which the other end 14 of the valve-actuating 15 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 cart-ridge 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 in-corporating 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 pressurizing agent, ego a fluorocarbon such as dichloro-difluoromethane. the cartridge 19 also has a nozzle 24 having a fine bore (not shown) extending longitudinally there through.
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 extend through nozzle 24. the bore is typically of 1 my diameter while the tip of the nozzle 24 is , Lo 33~
11 32892 typically of hemispherical configuration of 3 - 5 mm diameter.
Cartridge lo 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 5 mounded from an electrically insulating plastics material and is pivotal mounted in a boss 29 in shell mound 7 and a cores-pounding boss in the other shell mound. Cap 28 has an integral latch 30 engaging it a projection 31 mounded integrally with sleeve 5.
Extending through an opening 32 in sleeve 5 is a spring metal contact strip 33 which is held in place between -the shell moldings and the wall of sleeve I Electrically con-netted, ego 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 mounding 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 Nazi 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 prom mounting lo causes flange 25 to be depressed thus opening the valve the tree 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 JO
As mentioned herein before, extending round sleeve 5 is 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 mounding 7 and is electrically connected, ago.
TO
Cartridge lo 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 5 mounded from an electrically insulating plastics material and is pivotal mounted in a boss 29 in shell mound 7 and a cores-pounding boss in the other shell mound. Cap 28 has an integral latch 30 engaging it a projection 31 mounded integrally with sleeve 5.
Extending through an opening 32 in sleeve 5 is a spring metal contact strip 33 which is held in place between -the shell moldings and the wall of sleeve I Electrically con-netted, ego 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 mounding 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 Nazi 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 prom mounting lo causes flange 25 to be depressed thus opening the valve the tree 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 JO
As mentioned herein before, extending round sleeve 5 is 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 mounding 7 and is electrically connected, ago.
TO
12 3 32802 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 5 valve actuating member 12, he handle portion 2 of the apparatus is shown in figure 30 Provided within the handle portion 2 of the casing is a compartment 41 for receipt of a series train of two dry cell batteries 42, a high voltage generator assembly 43; and a trigger assembly 44~
The generator assembly comprises a printed circuit board 45 on which are mounted the various components shown in figure 4 as enclosed within the dotter box For simplicity 15 these components are not shown in Figure 3. o'er 45 is mounter in a mounding 46 of electrically insulating plastics material.
Also mounted in mounding 46 is an output step transformer 47 which is connected to board 45 by leads 48, 49. the high volt age output from transformer 47 is fed, via a high voltage diode 20 50, (not shown in Figure 3), to the high voltage lead 34 via a contact within sleeve 51 attached to transformer 47~ me generator assembly 43 is located by projections 52, 53, 54 an 55 integral with shell mounding 7 and by corresponding projections (not shown) in the other shell molding Board 45 is provide with two electrical contacts 56, 57. Contact 56 is a spring metal s-trip which extends round mouldi~g 46 to the trigger assembly 44 while contact 57 projects into the battery compartment 41 wherein it contacts the positive terminal of the triune of batteries 42. Extending the length of 30 compartment 41 is a wire 58~ At the rear end ox compartment 41 wire 58 is wormed as a coil spring contact 59 which urges the trains of batteries 42 into engagement with context 57. Wire 58 also serves to connect the negative contact of the battery trait to the trigger assembly 440 Ike trigger assemblage 44 comprises a trigger lever 3 Lo 3;3 I
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 5 valve actuating member 12, he handle portion 2 of the apparatus is shown in figure 30 Provided within the handle portion 2 of the casing is a compartment 41 for receipt of a series train of two dry cell batteries 42, a high voltage generator assembly 43; and a trigger assembly 44~
The generator assembly comprises a printed circuit board 45 on which are mounted the various components shown in figure 4 as enclosed within the dotter box For simplicity 15 these components are not shown in Figure 3. o'er 45 is mounter in a mounding 46 of electrically insulating plastics material.
Also mounted in mounding 46 is an output step transformer 47 which is connected to board 45 by leads 48, 49. the high volt age output from transformer 47 is fed, via a high voltage diode 20 50, (not shown in Figure 3), to the high voltage lead 34 via a contact within sleeve 51 attached to transformer 47~ me generator assembly 43 is located by projections 52, 53, 54 an 55 integral with shell mounding 7 and by corresponding projections (not shown) in the other shell molding Board 45 is provide with two electrical contacts 56, 57. Contact 56 is a spring metal s-trip which extends round mouldi~g 46 to the trigger assembly 44 while contact 57 projects into the battery compartment 41 wherein it contacts the positive terminal of the triune of batteries 42. Extending the length of 30 compartment 41 is a wire 58~ At the rear end ox compartment 41 wire 58 is wormed as a coil spring contact 59 which urges the trains of batteries 42 into engagement with context 57. Wire 58 also serves to connect the negative contact of the battery trait to the trigger assembly 440 Ike trigger assemblage 44 comprises a trigger lever 3 Lo 3;3 I
13 32802 made of an electrically conductive plastics material pivot-ably mounted on bosses 60 in the shell moldings. The free end of wire 58 from the battery compartment extends through a hole in lever 3 to form a contact pin 61. Also 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 Lyon the trigger lever 3 is in the "off" position.
Strip contact 56 is laterally spaced from lever 39 and hence insulated therefrom when the trigger is in the "off" position.
Rotation of lever 3 from the '70ff" 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.
rooked round an integral extension 63 to trigger 15 lever 3 is the connecting wire 39~ A return spring (not shown) is provided to bias lever 3 to the "off" position In use the operator's finger contacting trigger lever 3 provides a connection -through the operator, to earth thus earthing the field intensifying electrode 6 and the negative 20 side of the batter try Referring now to Figure 4, the low voltage part of the high voltage generator circuit consists of a conventional tray-sistorised saturation oscillator formed by the primary 64 of a first step-up transformer 65, resistor 66 and a transistor 67.
25 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. Connected in parallel with capacitor 69 is 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, ego wires 39 and 40, and -the field intensifying 35 electrode I
Strip contact 56 is laterally spaced from lever 39 and hence insulated therefrom when the trigger is in the "off" position.
Rotation of lever 3 from the '70ff" 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.
rooked round an integral extension 63 to trigger 15 lever 3 is the connecting wire 39~ A return spring (not shown) is provided to bias lever 3 to the "off" position In use the operator's finger contacting trigger lever 3 provides a connection -through the operator, to earth thus earthing the field intensifying electrode 6 and the negative 20 side of the batter try Referring now to Figure 4, the low voltage part of the high voltage generator circuit consists of a conventional tray-sistorised saturation oscillator formed by the primary 64 of a first step-up transformer 65, resistor 66 and a transistor 67.
25 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. Connected in parallel with capacitor 69 is 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, ego wires 39 and 40, and -the field intensifying 35 electrode I
14 32802 Jo ensure that the capacitor 71 has the desired value, typically 20 - 40 pi, guides (not shown) may be provided in the shell moldings to hold ire 39 in the desired spatial relationship to the high voltage lead OWE
In operation the saturation oscillator gives rise to current pulses in the secondary of transformer 65 which charge capacitor 69 via diode 68. When the voltage across capacitor 69 reaches the striking voltage of gas-gap discharge tube 707 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.
Typically the striking voltage is 150 - 250 V and the extinguish-in voltage is less than 10 V.
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 be-tweet nozzle 24 and the field intensifying electrode 6 for electrostatic atomization of the liquid from nozzle 24, the frequency with which the high voltage pulses are produced is determined by the value of capacitor 69, the impede ante of the secondary of transformer 65 and the magnitude and frequency of the pulses produced by the saturation oscillator.
In an example a pesticide composition of receptivity 8 x 107 ohm. cm was sprayed from apparatus of the type shown in figures 1 to 4. The voltage at noble 24 was about 18 XV, the liquid flow rate 1 ml/min, the frequency of the high voltage pulses about 25 I The capacitance of capacitor 71 was about 20 pi and primarily formed by the capacitance between wires 34 and 39 which were each about OWE m long and spaced apart by an average of about 2 cm. The series train of batteries 42 gave a voltage of 301 V and the current drain thereon was about 150 Mao In the modified circuit of figure 5 the arrangement of the generator is modified by the replacement of the gas-gap disk charge tube 70 by a thruster 72 and by the incorporation of a ~2~335 temperature dependent triggering circuit 73, the output of~rhich is applied to the gate of thruster 72.
his temperature dependent triggering circuit incorp-orates a temperature sensitive component, e.g. a thermistor, and is arranged such that as the temperature increases, thruster 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 trays-for of energy to the high voltage circuit is increased thus giving an increased voltage at the nozzle 24.
As the temperature increases 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.
PANG
7 June 19~4
In operation the saturation oscillator gives rise to current pulses in the secondary of transformer 65 which charge capacitor 69 via diode 68. When the voltage across capacitor 69 reaches the striking voltage of gas-gap discharge tube 707 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.
Typically the striking voltage is 150 - 250 V and the extinguish-in voltage is less than 10 V.
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 be-tweet nozzle 24 and the field intensifying electrode 6 for electrostatic atomization of the liquid from nozzle 24, the frequency with which the high voltage pulses are produced is determined by the value of capacitor 69, the impede ante of the secondary of transformer 65 and the magnitude and frequency of the pulses produced by the saturation oscillator.
In an example a pesticide composition of receptivity 8 x 107 ohm. cm was sprayed from apparatus of the type shown in figures 1 to 4. The voltage at noble 24 was about 18 XV, the liquid flow rate 1 ml/min, the frequency of the high voltage pulses about 25 I The capacitance of capacitor 71 was about 20 pi and primarily formed by the capacitance between wires 34 and 39 which were each about OWE m long and spaced apart by an average of about 2 cm. The series train of batteries 42 gave a voltage of 301 V and the current drain thereon was about 150 Mao In the modified circuit of figure 5 the arrangement of the generator is modified by the replacement of the gas-gap disk charge tube 70 by a thruster 72 and by the incorporation of a ~2~335 temperature dependent triggering circuit 73, the output of~rhich is applied to the gate of thruster 72.
his temperature dependent triggering circuit incorp-orates a temperature sensitive component, e.g. a thermistor, and is arranged such that as the temperature increases, thruster 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 trays-for of energy to the high voltage circuit is increased thus giving an increased voltage at the nozzle 24.
As the temperature increases 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.
PANG
7 June 19~4
Claims (10)
1. Portable electrostatic spraying apparatus including (a) a spray nozzle, (b) means to supply liquid to be sprayed to said spray nozzle, (c) a low voltage power source, (d) a high voltage generator powered by said low voltage power source, whereby rectified high voltage pulses May be produced across its output, (e) a capacitor connected to said nozzle and to one side of said generator output, whereby said capacitor may be charged by said rectified high voltage pulses so that said nozzle may be maintained at a sufficiently high potential, with respect to the other side of said generator output, to cause electro-static atomisation of said liquid at said nozzle, characterised in that capacitor has a value below pF, where V is the average voltage, expressed in kilovolts, that said generator is capable of maintaining at said nozzle, and in that said capacitor is formed by the capacitance between a lead con-necting said one side of the generator output to said nozzle and a lead connected to said other side of the generator output, said generator being capable of producing said high voltage pulses of such 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 dis-charge.
2. Apparatus according to claim 1 wherein said capacitor has a value above pF.
3. Apparatus according to claim 1 wherein said capacitor has a value between 10 and 50 pF.
4. Apparatus according to claim 1 wherein said generator is capable of maintaining a voltage between 10 and 25 kV at said nozzle.
5. Apparatus according to claim 1 wherein said high voltage pulses are rectified in said generator by a diode having a leakage current of less than 1 pA at 37 kV and 20°C.
6. Apparatus according to claim 1 wherein said generator includes a capacitor that can be discharged through the primary of a step-up transformer via a triggering device whereby dis-charge of said capacitor through said primary produces high volt-age pulses in the secondary of said transformer.
7. Apparatus according to claim 1 wherein said generator produces said high voltage pulses at a frequency below 50 Hz.
8. Apparatus according to claim 1 wherein an electrically conductive member is positioned adjacent to, but spaced from said nozzle, and connected to said other side of the generator output, and said capacitor of value below pF is formed by the lead connecting said one side of the generator output to said nozzle and the lead connecting said other side of the gener-ator output to said electrically conductive member.
9. Apparatus according to claim 1 wherein said means to supply liquid to said spray nozzle includes a mechanically operated valve actuated by a trigger remote from said valve and said capacitor of value below pF is formed by the lead connecting said one side of the generator output to said nozzle and an electrically conductive member forming part of the mechanical connection from said trigger to said valve, said electrically con-ductive member being electrically connected to said other side of the generator output.
10. Apparatus according to claim 1 wherein said means to supply liquid to said nozzle includes a pressurised container and means axe provided to monitor the ambient temperature and to vary the average voltage applied to the nozzle in response to said monitored temperature to maintain the average droplet size of the liquid sprayed from said nozzle within a predetermined range.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB838319225A GB8319225D0 (en) | 1983-07-15 | 1983-07-15 | Electrostatic spraying |
| GB838319226A GB8319226D0 (en) | 1983-07-15 | 1983-07-15 | Electrostatic spraying |
| GB8319226 | 1983-07-15 | ||
| GB8319225 | 1983-07-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1220335A true CA1220335A (en) | 1987-04-14 |
Family
ID=26286613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000458271A Expired CA1220335A (en) | 1983-07-15 | 1984-07-06 | Electrostatic spraying |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0132062B1 (en) |
| AU (1) | AU3035384A (en) |
| CA (1) | CA1220335A (en) |
| DE (1) | DE3461353D1 (en) |
| DK (1) | DK346684A (en) |
| GB (1) | GB8415981D0 (en) |
| NO (1) | NO842849L (en) |
| NZ (1) | NZ208684A (en) |
Families Citing this family (5)
| 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 |
| GB9115278D0 (en) * | 1991-07-15 | 1991-08-28 | Unilever Plc | Liquid spraying apparatus and method |
| GB9115275D0 (en) * | 1991-07-15 | 1991-08-28 | Unilever Plc | Colour cosmetic spray system |
| GB9115276D0 (en) * | 1991-07-15 | 1991-08-28 | Unilever Plc | Skin treatment system |
Family Cites Families (4)
| 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 |
-
1984
- 1984-06-22 EP EP84304256A patent/EP0132062B1/en not_active Expired
- 1984-06-22 DE DE8484304256T patent/DE3461353D1/en not_active Expired
- 1984-06-22 GB GB848415981A patent/GB8415981D0/en active Pending
- 1984-06-27 NZ NZ208684A patent/NZ208684A/en unknown
- 1984-07-06 CA CA000458271A patent/CA1220335A/en not_active Expired
- 1984-07-06 AU AU30353/84A patent/AU3035384A/en not_active Abandoned
- 1984-07-12 NO NO842849A patent/NO842849L/en unknown
- 1984-07-13 DK DK346684A patent/DK346684A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| DK346684D0 (en) | 1984-07-13 |
| DE3461353D1 (en) | 1987-01-08 |
| EP0132062A1 (en) | 1985-01-23 |
| NO842849L (en) | 1985-01-16 |
| DK346684A (en) | 1985-01-16 |
| NZ208684A (en) | 1986-12-05 |
| GB8415981D0 (en) | 1984-07-25 |
| AU3035384A (en) | 1985-01-17 |
| EP0132062B1 (en) | 1986-11-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |