Patent Publication Number: US-2006011737-A1

Title: Liquid spray head, apparatus comprising a liquid spray-head and container therefore

Description:
The invention relates to a liquid spray-head, comprising: a housing, to be secured to a container containing a sprayable liquid; a liquid ejecting member connected to said housing, to be contacted with a liquid providing member for providing liquid to said liquid ejecting member; and a vibrating actuator connected to said liquid ejecting member for actuating said liquid ejecting member so as to generate a spray of liquid.  
      From EP-A-0615470 an apparatus is known for atomizing a liquid to be used, that is to say, for producing micro-droplets of liquid, for example, in an atomizing device for insecticide or air freshener liquid. The apparatus is based on a liquid ejecting membrane mechanically connected to an electromechanical actuator, preferably an electro-acoustic element, to make the membrane vibrate and means for supplying the liquid directly to a surface of the membrane. The liquid is atomized from the membrane due to its vibrating motion. The membrane can be perforated, in which case the liquid is atomized through it. Said means for supplying the liquid to the membrane comprise a capillary mechanism constituted by a wick made of open cell foam or fibre with a first end submerged in the liquid and a second end in contact with the membrane. The electro-acoustic actuator is formed by a laminar composite material comprised of a first active layer, which can be either an electrostrictive member, such as a piezoelectric, or a magnetostrictive member, and a second layer which can be either active or negative, mechanically joined. An enlarged field applied by means of electrodes makes that the first active layer tries to change its length in the direction of the plane, which causes a mechanic reaction with the second layer which provokes that the electro-acoustic actuator is bent. A driving circuit activates the electro-acoustic actuator in order it carries out a resonating vibration. According to an exemplary embodiment, the electro-acoustic actuator adopts the shape of an annular disk and the membrane is arranged at the central opening of annular disk.  
      From U.S. Pat. No. 3,790,079 a liquid spraying head is known having a fixed connection between the liquid providing member and the liquid ejecting member. A supply tube delivering a sprayable liquid is directly coupled to a membrane. Such a fixed delivery arrangement has as a disadvantage that the piezo-element is not freely suspended by it hindered by the supply tube. Furthermore, the liquid ejecting member only vibrates in bending modes, since the perimeter is fixed to the housing by a fixing ring.  
      The object of this invention is to supply an liquid spray-head which provides a state of contact without tightening or load between the liquid providing member and the liquid ejecting member in order that a contact under an excessive or incorrect pressure of the wick on the liquid ejecting member does not interfere in the vibrating motion of said liquid ejecting member at same time that the supply to the liquid ejecting member is carried out in an even and regular way, all of it regardless the service conditions or service slope positions of the device.  
      The above mentioned object is achieved by a liquid spray-head according to the preamble, wherein the spray-head comprises a flexible member extending from an outer perimeter of said liquid ejecting member to an inner wall of the housing for providing a flexible connection between said housing and said liquid ejecting member, the flexible member being arranged so as to provide a stable working contact between said liquid ejecting member and said liquid providing member.  
      With this arrangement, the flexible member supports the unit of the vibrating actuator and the liquid ejecting member so that the top end of the liquid providing member, and a contact side of the liquid ejecting member is kept in a contact state without tightness nor load which prevents that a contact under an excessive or incorrect pressure of the capillary sucking member on the liquid ejecting member interferes in the vibrating motion of the liquid ejecting member and makes that the supply of the liquid to the liquid ejecting member is even and continuous, regardless of the service conditions or service slope of the device. In addition, the arrangement of the flexible member provide a longer useful life to the liquid ejecting member and a greater flexibility which allows to place the device in different conditions or service slope positions.  
      In one embodiment, the flexible member is annulus-shaped, extending around the liquid ejecting member. The vibrating actuator may have a conventional disk or ring form enclosing or at least partially covering the liquid ejecting member. This embodiment provides the advantage that a uniform flexibility around the liquid ejecting member is provided. In this way, the liquid ejecting member is freely suspended, so that the liquid ejecting member can vibrate freely against the liquid providing member. An adequate flexibility is further provided by the flexible member being provided with a radial cross-section showing at least one undulation between a central opening and its periphery.  
      Preferably, the flexible member is provided with a radial cross-section extending from an outer perimeter of said liquid ejecting member to an inner wall of the housing for providing a flexible connection between said housing and said liquid ejecting member. Such a flexible connection allows a certain amplitude of lateral movement along a line extending from the perimeter of the liquid ejecting member to the inner wall of said housing so as to freely suspend the liquid ejecting member.  
      Preferably the flexible member is cone-shaped, the cone extending in a direction normal to an ejection side of the liquid ejecting member. The cone shape provides an improved working contact between the liquid ejecting member and the liquid providing member. Additionally, the cone may provide a directing effect for directing the spray in a substantial normal direction to the ejection side of the liquid ejecting member.  
      In a further embodiment, the flexible member comprises inwardly extending surface areas contacting opposite surfaces of said liquid ejecting member so as to enclose said liquid ejecting member. In this way, by providing a cost effective way to secure the liquid ejecting member to said flexible member the number of constituting parts of the spray-head can be minimized. As an alternative, the flexible member is provided with a inner perimeter that is matingly connected to a rim of the liquid ejecting member. As a further alternative, the flexible member is provided with an inner perimeter comprising a plurality of through-holes, the spray-head further comprising an enclosing member comprising protrusions entering said through-holes, for enclosing said liquid ejecting member by said enclosing member and said flexible member. Further, the inner perimeter comprises a notch for passage of connecting wires of the vibrating actuator.  
      In yet another embodiment, the flexible member is provided with a perimeter that is sealingly connectable to a rim of an opening of a liquid containing container. In this way, the flexible member seals off an opening of the container, thereby minimizing leakage or spill. To provide a better sealing effect, the flexible member is provided with a reinforced perimeter.  
      In a further embodiment, the spray-head is provided with a liquid providing member, the liquid spray-head further comprising an annular fixing member, for fixing said liquid providing member relative to the liquid ejecting member. This embodiment provides a stable and uniform positioning of the liquid providing member in relation to the flexible member and the liquid ejecting member contained thereby. For better liquid providing properties, said liquid providing member has a chamfered surface to be contacted with the liquid ejecting member. The chamfered surface the surface provides a better and more durable flow of liquid to the perforations of the liquid ejecting member.  
      Advantageously, the flexible member is moulded from an elastomeric material from a group comprising silicones, fluorinated elastomers, fluorosilicones, nitrile-butadiene (NBR), hydrogenated nitrile-butadiene (HNBR), thermoplastic polyester-elastomer, neoprene (cloroprene), terpolimer of etylpropilene (EPDM) and EPDM peroxide. Preferably, the elastomeric material is the fluorinate elastomer FKM 60. In yet another preferable embodiment, the flexible member is monolithically formed to the housing, thus providing a cost effective way of producing said spray-head.  
      The invention also relates to container for comprising liquid, to be secured to a liquid spray-head according any of the above describe features. In particular, the invention relates to a container comprising a liquid providing member and an annular fixing member, for fixing said liquid providing member. Preferably, the fixing member comprises an outer surface providing a sealing contact between the periphery of a flexible member of a spray-head and an inner surface fixedly contacting said liquid providing member. The liquid providing member preferably comprises a chamfered surface to be contacted with the liquid ejecting member.  
      In another respect, the invention relates to an apparatus for spraying a liquid, comprising a liquid spray-head according to any of the above aspects. Such an apparatus may comprise an electrical control circuit for controlling the liquid spray head, the control circuit comprising a timer circuit and/or an intensity switch. Furthermore, the apparatus may comprise a fan and a conduit for ducting fanned air over the spray-head. In a preferred embodiment, the apparatus is arranged to deliver fragrances. In this way, the apparatus can be used as an air freshener. Especially since no heating is involved in transporting the fragrances into the atmosphere, more sophisticated fragrances can be used that will not suffer from degradation by heat. Furthermore, the delivery system using the liquid spray head of the above described aspects offers an effective dose control that can be adjusted to certain timing (for instance: delivering a fragrance during a predetermined interval) and intensity.  
      In another embodiment the apparatus according the invention is an apparatus for exterminating crawling insects, comprising a liquid spray-head according to any of the preceding claims, a fan, an electrical control circuit and a conduit for ducting fanned air over the spray-head so as to provide a directed spray.  
      A preferred embodiment of said apparatus is provided by the fan comprising a rotor wheel having an axis of rotation parallel to an ejecting direction of the spray-head, wherein the conduit deflects fanned air in a direction transverse to said ejection direction. This embodiment allows for an especially flat design of the apparatus, allowing for placement in spaces having low altitude, like for instance under a cupboard etc.  
      The control circuit may be arranged to control the spray-head in at least two different operation modes previously programmed and stored in a memory associated to said control circuit, wherein in a first operation mode a first predetermined dose of liquid is sprayed during a first predetermined period of time for detection of crawling insects, and wherein in a second operation mode a second predetermined dose of liquid is sprayed during a second predetermined period of time, separated by a predetermined period from said first predetermined period of time, for effective extermination of crawling insects. Said operation modes may be selectable by a selector switch. 
    
    
      Further advantages and features will become apparent when reading the description in connection with the drawings. In the drawings:  
       FIG. 1  shows a perspective view of a preferred embodiment of an apparatus comprising a liquid spray-head according to the invention;  
       FIG. 2  is a diametral cross sectional view of the mounting of the liquid spray-head of this invention using a diaphragm according to a first exemplary embodiment;  
       FIG. 3  is a plan view of the diaphragm of  FIG. 2 ;  
       FIG. 4  is a diametral cross section of the mounting of the liquid spray-head of this invention using a diaphragm according to a second exemplary embodiment;  
       FIG. 5  is an exploded perspective view of part of the mounting of  FIG. 4 .  
       FIG. 6  contains a diagram of a diametrical section of the piezoelectric device mounting, made up of a central frame, an annular membrane and a perimeter frame.  
       FIG. 7  represents one half of a diametrical section of a mounting for the piezoelectric device in which the membrane is made up of ridges and troughs of the zigzag type.  
       FIG. 8  represents a similar view to  FIG. 7  with the membrane having wider, less frequently occurring ridges and troughs.  
       FIG. 9  represents a similar view to  FIGS. 7 and 8 , in which the membrane has narrower, more frequently occurring ridges and troughs.  
       FIG. 10  represents a similar view to  FIGS. 7-9 , in which the membrane has ridges and troughs of the undulated type.  
       FIG. 11  represents a similar view to  FIGS. 7-10 , in which the annular membrane is represented by its upper surface, in one case, by a continuous dotted line forming a single ridge with a curvilinear arched straight cross section and, in another case, by a broken dotted line forming a single trough having a curvilinear arched straight cross section.  
       FIG. 12  represents a similar view to  FIGS. 7-11  considered above, in which the annual membrane has, on its upper surface an exterior ridge and an inner trough, both concentrically shaped and of the undulating type.  
       FIG. 13  represents diagramatically an assembly of a device provided with a liquid container, the device incorporating a spray-head of the invention and forming a support enabling the workable positioning of a container holding the spray liquid;  
       FIG. 14  shows a plane view and side views of a preferred connection between the liquid ejecting member and the flexible member;  
       FIG. 15  shows a side view of a preferred embodiment of the flexible member and of the liquid providing member;  
       FIG. 16  is a view in perspective of the apparatus for controlling a crawling insect population of this invention;  
       FIG. 17  is a top plane view of the apparatus of  FIG. 18  with the cover withdrawn to show its interior;  
       FIG. 18  is a cross sectional view, with the cover included, taken across the plane III-III of  FIG. 17  in the direction of the arrows;  
       FIG. 19  is a diagram of the control electronic circuit of the apparatus operation; and  
       FIGS. 20 and 21  illustrate the method of the invention by means of schematic diagrams corresponding to the spreading flow rate of the active substance depending on the time in two different operation modes of the apparatus. 
    
    
      In  FIG. 1 , a perspective view is shown of an apparatus comprising a liquid spray-head according to the invention. The apparatus in  FIG. 1  is designed as a table piece  100 , comprising a base plate  101  and a structure  102  for holding a liquid container  103 . The liquid container  103  contains a liquid that produces an odour that can for instance be used for freshening the atmosphere. The liquid container  103  may be a refillable container or may be a replaceable unit that can be inserted once the container is empty. The liquid spray head will be further illustrated in subsequent figures; in  FIG. 1  an opening  104  is shown wherefrom liquid spray is ejected by the liquid ejecting head. The apparatus  100  is further provided with an on/off button  105  and a sliding contact  106  for controlling the intensity of the ejected spray. The preferred embodiment is provided with a timing circuit, that automatically turns the liquid spray off after a predetermined time, to prevent excessive spraying of fragrance.  
      Where conventional fresheners usually utilize heating for vapourizing liquids and for transporting the fragrances into the atmosphere, the apparatus according to the invention offers the advantage that no heating is involved. Hence, more sophisticated fragrances can be used that will not suffer from degradation by heat. Furthermore, the vaporizing action of the liquid spray-head according to the invention is immediate, hence an almost immediate effect is sensed when the apparatus according to the embodiment of  FIG. 1  is turned on.  
      In  FIG. 2 , the atomizing ultrasound spray-head comprises: a housing  13 , to be secured to a container containing a sprayable liquid; a circular perforated liquid ejecting membrane  3  connected to said housing  13 , to be contacted with a liquid providing wick  5  for providing liquid to membrane  3 ; and a ultrasound vibrating annular actuator  2  connected to said membrane  3  for actuating said membrane  3  so as to generate a spray of liquid. The ultrasound vibrating annular actuator  2  is composed of an active layer and a reaction layer, the circular perforated membrane  3  is coupled to a central opening of said vibrating annular actuator  2  to be vibrated by it and the capillary liquid providing member or wick  5  for supplying by capillarity said liquid directly to a surface of said perforated membrane  3 . Typically, the wick  5  is of open cell foamy polymeric material or of fibrous material and has a lower end submerged within a liquid contained in a container (not shown) and a top end  51  which is the one that contacts membrane  3 . The liquid is atomized through the perforated membrane  3  by the effect of the vibration thereof produced by the vibrating annular actuator  2 . According to a preferred application, not shown, a conveniently oriented airflow assists to spreading the atomized liquid.  
      As it is shown in  FIG. 2 , the spray-head comprises a flexible diaphragm  6  extending from an outer perimeter of said membrane  3  to an inner wall of the housing  13  for providing a flexible connection between said housing  13  and said membrane  3 . In this way, as is apparent from the figure, such flexible connection allows a certain amplitude of lateral movement along a line extending from the perimeter of the membrane  3  to the inner wall of the housing. Thus, by such a flexible connection, the liquid ejecting member is freely suspended, so that the liquid ejecting member can vibrate freely against the liquid providing member. The vibrating annular actuator  2  bearing the perforated membrane  3  is fastened on a central opening  65  of an annulus shaped elastic diaphragm  6  extending around the membrane  3 , which is supported on a housing  13 ,  14  or the like. Said container containing the liquid, to which the wick  5  is associated is also linked to said housing  13 ,  14 . In the example illustrated, a thickening  62  of the periphery of the diaphragm  6  is seated in a recess of a lower support  13  of said housing and a upper support  14 , which is integral with, for example a cover of the housing, tighten said thickening  62  or an adjacent area of the diaphragm  6  against the lower support  13 .  
      Thus, the diaphragm  6  supports, thanks to its elasticity, the unit of the vibrating annular actuator  2  and the perforated membrane  3  so that the wick  5  and the surface of the membrane  3  are kept in a state of contact without tightening nor load so that the wick  5  does not interfere in the vibrating motion of the membrane  3  and that the supply by capillarity of the liquid to the membrane  3  is even and continuous, regardless the service conditions or service slope positions of the device.  
      The elasticity of the diaphragm  6  is provided by a combination of material and geometric shape. Thus, on one hand, the diaphragm  6  is of an elastomeric material selected from a group comprising silicones, fluorinated elastomers, fluorosilicones, nitrile-butadiene (NBR), hydrogenated nitrile-butadiene (HNBR), thermoplastic polyester-elastomer, neoprene (cloroprene), terpolimer of etylpropilene (EPDM) and EPDM peroxide, preferably the fluorinate elastomer FKM 60, and on the other hand, the diaphragm  6  is annulus-shaped (see  FIGS. 3 and 4 ) and is provided with a radial cross section showing one or more undulations  61  between said central opening and its periphery which provides them an elasticity very sensible to the vibrating motions which extends the useful life of the membrane and facilitates placing the device in different service slope positions. According to an exemplary embodiment shown in  FIGS. 2 and 3 , and as it can be seen in said radial cross section shown in  FIG. 2 , said undulation  61  has a zigzag profile with rounded sides and comprises a single cycle. In  FIGS. 4 and 5 , another embodiment is shown in which the profile of the cross section of the diaphragm  6  has straight sides and rounded vortices and comprises two complete cycles. Other configurations of the profile and/or other number of cycles are possible as is apparent from embodiments shown by way of example in  FIGS. 6-15 .  
      In both cases, the undulated area of said diaphragm  6  has a constant thickness while on the periphery it shows said reinforcing thickening  62  and on an area close to the central opening  65 , a fastening configuration  63 ,  66  for mounting the vibrating annular actuator  2 . Optionally, the diaphragm  6  in addition includes a notch  64  (see  FIGS. 3 and 5 ) on the edge of the central opening  65  for the passage of connecting wires of the vibrating annular actuator.  
       FIG. 5  shows the characteristics of said mounting. In said fastening configuration a flat portion  63  is included around said central opening  65  where through holes  66  are provided in which stubs  121  arranged on the periphery of a mounting ring  12  are pressure inserted. Said mounting ring  12  is provided with a recessed flat portion  122  located around a central opening, a metallic ring  21  for supporting the peripheral edge of the vibrating annular actuator  2  remains trapped between both flat portions  63 ,  122  of the diaphragm  6  fastening configuration and the mounting ring  12 .  
       FIG. 6  shows a diaphragm  1  for a electro-acoustic type piezoelectric device  2 , which is made up of a central frame  3 , a resilient sheet  4  and a perimeter frame  5 . The diaphragm  1 , central frame  3 , resilient sheet  4  and perimeter frame  5  form an integral unit obtained from synthetic elastomeric resin, preferably fluor elastomer, such as “VITON” by Du Pont, but this does not exclude the possibility of using, albeit with varying results, silicones, polyurethane elastomer, fluorosilicones, NBR (Nitrile Butadiene Rubber), thermoplastic polyester-elastomer, HNBR (Hydrogenate Nitrile Butadiene Rubber), neoprene (chloroprene), EPDM (Ethylene-Propylene Terpolymer rubber) and EPDM peroxide.  
      Diaphragm  1  is fitted by any conventional means through pressure P that is applied to the whole surface of perimeter frame  5  in order to apply it to a housing  6  which, forming part of a spray apparatus that is not represented herein, enables a container  7  holding the spray liquid to be positioned in a workable manner by means of a thread engagement, bayonet engagement etc.  
      In  FIG. 7 , diaphragm  1  is fixed to housing  6  by means of a clamping device consisting of two jaws  8  and  9  which fix bead  10  in which perimeter frame  5  is formed.  
      In  FIGS. 8, 9  and  10 , this fixing arrangement is achieved by a flexible diaphragm provided with a skirting  12  having a groove  11  that is sealingly connectable by snap engagement to a projection  13  or notch  14  of an opening of a liquid containing container.  
      Piezoelectric device  2  can be fixed to central frame  3  by means of an adhesive, as in  FIG. 6 , by means of a central ring  15  that is joined to central frame  3  by welding, or by means of riveted lugs  16 , or the like, that firmly fix the piezoelectric device between them, as in  FIGS. 7, 8 ,  10 - 12  or, by means of an annular housing  17  which, like a pocket, is formed within central frame  3  proper, or incorporated therein. In this way the diaphragm  1  is provided with an inner perimeter comprising a plurality of through-holes, so that an enclosing annular housing  17  comprising lugs  16  enters said through-holes, for enclosing the piezo-electric device holding nozzle  2 A by said enclosing member  17  and said diaphragm  1 .  
      As shown in  FIGS. 6-12 , by means of mounting  1  for piezoelectric device  2 , it is possible that nozzle  2 A is always applied to the head of a liquid providing wick  18 , by maintaining a thin layer of spray liquid always in contact with nozzle  2 A of piezoelectric device  2 , which does not need any priming. At the same time, owing to the gentle, controlled pressure with which said nozzle  2 A is applied to the head of wick  18  provided by the flexibility and elasticity of mounting  1 , determines the correct operation of the spray function.  
      In  FIG. 13 a  spray-head is illustrated having a liquid container  7 . In this arrangement, the container  7  comprises a liquid providing wick  18 , and an annular fixing member  7 A, for fixing said wick relative to the nozzle  2 A. Hence the fixing member  7 A forms a support enabling the workable positioning of wick  18 . As will be understood, the invention is also related to charactering features of the container per se.  
       FIG. 14  shows a plane view and side views of an embodiment wherein the diaphragm  131  comprises inwardly extending surface areas  132 ,  133  contacting opposite surfaces  134 ,  135  of said liquid ejecting member  136  so as to enclose said liquid ejecting member  136 .  
       FIG. 15  shows a side view of a preferred embodiment of the flexible member  141  and of the liquid providing member  142 . The flexible member is cone-shaped, the cone extending in a direction normal to an ejection side  143  of the liquid ejecting membrane  144 . The cone shape provides an improved working contact between the membrane  144  and the wick  142 . Additionally, the cone may provide a directing effect for directing the spray in a substantial normal direction to the ejection side  143  of the membrane  144 . The liquid providing member or wick  142  shown in  FIG. 15  comprises a chamfered contacting surface  145  for contacting the liquid ejecting member  144 . The chamfered surface  145  provides a better and more durable flow of liquid to the liquid ejecting member  144 .  
      Referring to FIGS.  16  to  18 , in which a preferred embodiment of the apparatus for exterminating crawling insects according to the invention is shown, comprising a liquid spray-head  2 , a fan  16 , an electrical control circuit  20  and a conduit  153  for ducting fanned air over the spray-head  2  so as to provide a directed spray. The housing of the apparatus is embodied by a bottom  1  and a cover  15  which jointly form an internal enclosure serving as support and protection to the remaining components forming the apparatus.  
      Said components contained in the housing  1 ,  15 , basically include a piezoelectric atomizer  2 , a container  4  for a liquid active substance L; a capillary sucking member, such as a wick  5 , for providing this liquid active substance L from said container  4  to the piezoelectric atomizer  2 ; a fan  16 ; electronic means  30  for controlling the operation of the piezoelectric atomizer  2  and fan  16 ; and a power supply  18  for supplying the different components which require it. In the embodiment illustrated in  FIGS. 17 and 18 , the fan  16  comprises a rotorwheel having an axis of rotation parallel to an ejecting direction of the spray-head  2 , wherein the conduit  153  deflects fanned air in a direction transverse to said ejection direction. This embodiment allows for an especially flat design of the apparatus, allowing for placement in spaces having low altitude, like for instance under a cupboard etc.  
      Said control electronic means  30  are advantageously incorporated in a printed circuit board  20  which in addition incorporates a selector switch  32  and a power on light  38 . This selector switch  32 , which is accessible from outside the housing  1 ,  15 , allows that the user starts or stops the apparatus and selects a specific operation mode from at least two different operation modes previously programmed and stored in a memory associated to the control electronic means  30 . These operation modes are adapted for carrying out different tasks required for an effective extermination of the crawling insects and will be described below with respect to  FIGS. 20 and 21 .  
      The piezoelectric atomizer  2  comprises an ultrasonic vibrating annular actuator, composed of a active layer and a reaction layer and a circular multiperforated membrane  3  connected to a central opening of that vibrating annular actuator to be vibrated by it. The piezoelectric atomizer  2  is supported by new elastic or flexible means, provided by a diaphragm  6 , which makes sure a contact without tightness or load of the wick  5  and the surface of membrane  3 . This makes that the wick  5  does not interfere in the vibrating motion of the membrane  3  and that the supply by capillarity of the liquid to the membrane  3  is even and continuous, regardless the conditions or positions of the operating slope of the device. The elasticity of the diaphragm  6  is provided by a combination of the elastomeric material of which it is made and its circular crown geometric shape which includes one or more circumferential concentric waves  61  between a central opening  66  and its external periphery  62 .  
      Said container  4  containing the liquid L incorporates a wick  5  and the assembly is housed in a recess  19  provided for that purpose at the lower part of the housing  1 ,  15 , in such a position that a top end  51  of the wick  5  is contacting the membrane  3  while a lower end  52  of it is submerged in the liquid L. Said recess  19  is accessible from outside, as shown in  FIG. 16  so that the assembly of container  4  and wick  5  is easily replaceable. Fastening the container  4  to the bottom  1  of the housing is carried out by respective threadings  41 ,  191 .  
      The cover  15  shows a first opening  151  located on the multiperforated membrane  3  of the piezoelectric atomizer  2 , for allowing the jet of atomized L active substance go out through it and a second opening communicated with an internal space  153  of the housing where said fan  16  is housed, for allow an air flow (shown by arrows) go out and laterally hit said jet of atomized L substance just above the first opening  151  in order to spread the atomized L substance in a limited extension area adjacent to the spreading apparatus.  
      The cover  15  in addition comprises a depression  154  on one side, in that depression a first window  155  is arranged through which there is an access to the selector switch  32  and a second window  156  through which said power on light  38  is visible, said selector switch  32  and power on light  38  being incorporated together with the electronic means  30  on the printed circuit board  20  housed and fastened within the housing  1 ,  15  in a suitable position, as it has been described above.  
      Preferably, said power supply  18  comprises one or several concatenated batteries  181  housed in that housing  1 ,  15 , which provides the apparatus with a very advantageous autonomy. However, the power supply could also comprise, for example, a transformer for adapting a current coming from outside through a connecting cable (not shown).  
      In  FIG. 19  the electric circuit of the apparatus of this invention is shown including control electronic means  30  incorporated in said printed circuit plate  20 .  
      The components incorporated on the printed circuit board  20  include a programmable integrated circuit (PIC)  31  which allows to activate and deactivate subsystems required according to one of the different operation cycles programmed and designed for correctly supplying active substance according to said different programs. Said selector switch  32  and the power on light  38 , which is in the form of an emitting light diode (LED), are connected to that programmable integrated circuit  31 . Connected to said batteries  181  a voltage booster regulator (VBR)  34  is arranged which can be an amplifier or transformer, the function of which is to boost the voltage of concatenated batteries  18  to the voltage necessary for supplying an oscillator circuit mentioned below. Said voltage booster regulator  34  is controlled by PIC  31 . A linear regulator  35 , supplied by the line at increased voltage and regulated by said VBR  34 , has the function to transform this voltage into the voltage required for a subsequent oscillator circuit (RCL)  37 . The linear regulator  35  is also controlled by PIC  31 . Said oscillator circuit  37  is controlled by an oscillator control device  36  the function of which is to commute the oscillator circuit to the mains or towards the earth. It is controlled by PIC  31  and it is supplied by the voltage generated by the linear regulator  35 . This device in addition possesses a potentiometer allowing to set the final resonance frequency within a preestablished range. Last, the oscillator circuit  37  is composed of resistors, coils and condensers, which generate an oscillation at a given frequency of resonance. Its on/off state is controlled by said oscillator control device  36  for generating excitation pulses of the mentioned piezoelectric atomizer  2 . Motor  17  driving the fan  16  is supplied at the voltage provided by the batteries  18  and its operation is also controlled by PIC  31 .  
      The procedure for controlling a crawling insect population according to this invention is described below with reference to  FIGS. 20 and 21 .  
      The procedure essentially comprises spreading at least one active substance, specific for said insects, by means of an electronically controlled spreading apparatus, such as the apparatus of this invention described above, for dosing said substance in an area having a limited extent where it is assumed or sure that there exists a population of said crawling insects, such as cockroaches. The control circuit  30  is arranged to control the spray-head  2  in at least two different operation modes previously programmed and stored in a memory associated to said control circuit, wherein in a first operation mode a first predetermined dose of liquid is sprayed during a first predetermined period of time for detection of crawling insects, and wherein in a second operation mode a second predetermined dose of liquid is sprayed during a second predetermined period of time, separated by a predetermined period from said first predetermined period of time, for effective extermination of crawling insects.  
      Said operation modes include a detection mode, to be applied in an area where it is assumed that there exists a population of said crawling insects for confirming the existence or no existence of said population in said area, and a treatment mode, to be applied in an area where it is sure there exists a population of said crawling insects, for exterminating or controlling said population in that area.  
      These two operation modes of the apparatus allow to apply the full procedure of the invention including the detection and further treatment of the insect plague. The procedure comprises, to start initially the spreading apparatus with said detection mode selected and thereafter place the spreading apparatus prepared this way in a first area where it is assumed there exists a population of said crawling insects. If in said first area submitted to the detection mode there appears a given number of crawling insects, then start the spreading apparatus with said selected treatment mode and thereafter place again the spreading apparatus thus prepared in that first area where the existence of the crawling insect population has been detected. If, on the contrary, there appears no insects in the first area, then start again the spreading apparatus with said selected detection mode and thereafter place the spreading apparatus thus prepared in a second area where it is also assumed that there exists a crawling insect population and so on until finishing the inspection and treatment in the suspected areas.  
       FIG. 20  shows a diagram of flow rate against time corresponding to operation of the spreading apparatus in the detection mode, which, once started follows steps A 1 ) to A 3 ) described hereinafter. A first step A 1 ) consists in remaining idle for a predetermined period of time  11 , considered sufficient for allowing an user to place the apparatus in the selected area without being affected by a premature spreading of said active substance. Following step A 2 ) consists in spreading the active substance during a period of time  12  by means of a pulse sequence n 1  of predetermined flow rate c 1 , frequency and time t 3  until completing a dose considered sufficient for having the crawling insects going out of their hiding places. Finally, step A 3 ) consists in stopping the operation of the spreading apparatus, with which the inspection step is finished and the user can withdraw the apparatus from the inspected area and proceed to inspecting a new area or proceed to treating that area.  
      In  FIG. 21 a  diagram of flow rate against time is shown corresponding to the operation of the spreading apparatus in the treatment mode, which, once started, follows steps B 1 ) to B 5 ) described hereinafter. A first step B 1 ) comprises remaining idle for a predetermined period of time  14 , considered sufficient for allowing an user to place the apparatus in the selected area without being affected by a premature spreading of said active substance. Following step B 2 ) consists in spreading the active substance during a time t 5  by means of a pulse sequence n 2  of predetermined flow rate c 2 , frequency and time t 6 , until completing a dose considered sufficient for effecting a lethal shock on the crawling insects. Then, a step B 3 ) comprises remaining idle again during a second period of time t 7  considered sufficient to allow any egg or latent larva is metamorphosed into an insect. Following step B 4 ) consists in subsequently spreading the active substance during a predetermined period of time t 8  by means of a sequence of predetermined flow rate c 3  pulses, frequency and time t 9  until completing a subsequent dose considered sufficient for producing a lethal effect on the surviving insects of the prior atomizing period of time or metamorphosed thereafter. Finally, the last step B 5 ) consists in stopping the operation of the spreading apparatus, after which the treatment is finished and the user can withdraw the apparatus from the area treated.  
      Advantageously, the treatment mode includes repeating steps B 3 ) and B 4 ) a given number of times considered sufficient for maintaining said lethal effect before proceeding to the last step B 5 ).  
      Although the active substance can be of a single component, it is advantageously formed from a mixture of different components leading to achieve different effects on the crawling insects. Preferably, the active substance used with the procedure and the apparatus of this invention is a mixture of at least three components at least one of them selected from the group of the pyrethroids type. Each of the three components is engaged in achieving one of the following effects on the crawling insects: hyperactivity; elimination; and disruption of the reproduction cycle. The three components are in said mixture in suitable proportions in order that each is effective when the mixture is spread at one of the different conditions of programmed dosing. That is to say, the first component is active for affecting the insects when the mixture is dosed in accordance with the detection mode, the second component is effective for exterminating the insects when the mixture is dosed in accordance with step B 2 ) of the treatment mode and the third component is effective for disrupting the reproduction cycle of the insects when the mixture is dosed in accordance with steps B 2  and B 4 ) of the treatment mode.  
      By way of example, and only for offering an order of magnitude of the parameters under which the apparatus acts in accordance with the different operation modes, indicative values are provided for that parameters.  
      In the inspection mode ( FIG. 20 ), the initial waiting time t 1  can be approximately 2 minutes, the pulses sequence n 1  can include approximately 17 pulses with a time t 3  of 5 s at a frequency of 10 s and releasing a flow c 1  of approximately 3 mg of active substance per second, which means applying a dose of approximately 255 mg along a time t 2  of 165 seconds.  
      In steps B 1 ) and B 2 ) of the treatment mode ( FIG. 21 ), the initial waiting time t 3  can be approximately 4 hours, the pulses sequence n 2  can include approximately 228 pulses with a time t 6  of approximately 5 s at a frequency of 10 s and releasing a flow of approximately 3 mg of active substance per second, which means applying a dose of approximately 3420 mg along during a time t 5  of 37 minutes and 55 seconds.  
      Last, in steps B 3 ) and B 4 ) of the treatment mode ( FIG. 21 ), the off time t 7  can be approximately 7 days, the pulses sequence n 3  can include approximately 114 pulses with a time t 9  of approximately 5 s at a frequency of 10 s and releasing a flow of approximately 3 mg of active substance per second, which means applying a dose of approximately 3420 mg during a time t 8  of 37 minutes and 55 seconds.  
      However, it must be stated that other dosing parameters are possible, as well as other variations in the procedure and apparatus. Although the invention has been illustrated with reference to piezo-electric actuators, other type of actuators, such as electro- or magnetostrictive actuators may be used. Further, various variations may be possible, for instance, a separate fixing ring placed in the container for fixing the liquid providing member, a ring placed between the container opening and the flexible diaphragm, a connecting element connecting the diaphragm and the liquid ejecting member. These and other variations are deemed to fall in the scope of the invention, as defined in the annexed claims.