Patent Publication Number: US-6666357-B2

Title: Dynamic air replenishing device for liquid product dispenser

Description:
The present invention relates to an air-intake device for drawing air into a liquid dispenser. 
     A liquid dispenser is generally equipped with a rigid reservoir and with an atmospheric pump provided, in particular, with a cylindrical and conical body and with a support flange co-operating, as applicable, with an assembly ring or with an assembly cap crimped to the neck of the reservoir, while bearing against a sealing gasket surrounding the pump body. 
     A metered quantity or “dose” of liquid being dispensed generates suction in the fixed-capacity reservoir, and it is necessary to compensate for said suction by drawing in a corresponding volume of air. To this end, the pump body is provided with vent orifices suitable for putting the internal volume of the reservoir into communication with the outside during the final stage of dispensing. 
     Another technique for re-establishing the pressure balance necessary for the dispenser to operate properly consists in providing clearance between the fixing flange and/or the pump body and the neck of the reservoir and/or the assembly cap so as to enable air to be sucked in. 
     However, in all known techniques, the vent-forming means also enable liquid to leak out, especially when the level of liquid is above the vent, either by construction or by the dispenser being used specifically in the upside down position. 
     An object of the present invention is to solve those technical problems satisfactorily without modifying the conventional structure of dispensers. 
     The invention achieves this object by means of an air-intake device characterized in that it comprises a flat annular gasket-forming washer whose free edge is in leaktight abutment towards the outside under a frustoconical shoulder carried by a collar engaged over said pump body, and is capable of being deformed elastically under the effect of internal suction to enable air to be drawn in. 
     In a specific embodiment, said frustoconical shoulder is formed directly on the outside side wall of the body of the pump. 
     In another embodiment, said frustoconical shoulder is carried by a collar engaged over said pump body. 
     According to an advantageous characteristic, said washer is provided with at least one radial slot extending from the free edge to facilitate deforming said free edge. 
     According to another characteristic, when the pump is in the closed position, the inside edge of said washer is deflected inwards under stress while having a portion of its outside face in contact with said shoulder. 
     In a variant, the inside face of said washer is provided with a peripheral keying groove serving to receive a rib provided on the top periphery of the reservoir. 
     The device of the invention makes it possible for sufficient air to be drawn in, while also guaranteeing that the dispenser is airtight. 
     The flexibility and elasticity of the annular gasket may be adjusted as a function of the level of suction generated in the reservoir due to liquid being dispensed. 
     The device of the invention is applicable to precompression pumps with or without vent orifices, without it being necessary to modify their structure. 
    
    
     The invention will be better understood on reading the following description with reference to the accompanying drawings, in which: 
     FIG. 1A is a view in section of an embodiment of the invention in the rest position; 
     FIG. 1B is a view in section of an embodiment of the FIG. 1A device during the air-intake stage; 
     FIG. 2A is a view in section of another embodiment of the device of the invention in the rest position; 
     FIG. 2B is a view in section of the device shown in FIG. 2A during the air-intake stage; and 
     FIG. 3 is a view in perspective of the flat annular gasket used in the invention. 
    
    
     The device of the invention is designed to be used in a liquid dispenser for the purpose of acting after each occasion on which liquid is dispensed to enable air to be drawn into a rigid reservoir R (shown in part in the figures) containing the liquid. 
     This dispenser is equipped with an atmospheric pump P provided, in particular, with a cylindrical and conical body C underlying a support flange S fixed to the neck of the reservoir R while bearing against a sealing gasket surrounding the body C. 
     The dispenser shown further includes a pusher knob K carried by a spray head T mounted on the spray tube of the pump P, and a metal assembly ring D crimped both onto the flange S of the pump and onto the neck of the reservoir R, thereby holding the sealing gasket captive. 
     The device of the invention comprises a flat annular gasket-forming washer  1  provided with a free edge  10  suitable for being deformed elastically under the effect of internal suction so as to enable air to be taken into the reservoir R. The inside face of the washer  1  is provided with a keying groove  12  designed to receive a rib N having a complementary shape and provided on the top periphery of the reservoir R. 
     In the embodiment of FIGS. 1A and 1B, the frustoconical shoulder  20  is formed directly by being integrally molded with the outside side wall of the body C of the pump P. 
     In this embodiment, the pump P is provided with a vent orifice E passing through the wall of the body C above the shoulder  20  and opening out above the washer  1  inside the ring D. 
     As shown in FIG. 1A, when the pump P is at rest in the closed position, the free edge  10  of the washer  1  is in leaktight abutment towards the outside, i.e. upwards in this example, under the frustoconical shoulder  2 . 
     In this position, the free edge  10  is deflected inwards, i.e. downwards in this example, under stress, while having a portion of its outside face  11  in contact with the shoulder  20 . 
     After a dose of liquid has been dispensed, the pusher knob K rises with the spray tube of the pump P, thereby generating suction inside the reservoir R. 
     This suction causes the free edge  10  of the washer  1  to be deformed elastically towards the inside of the reservoir R. 
     On coming out of abutment with the shoulder  20 , the free edge  10  of the washer  1  opens a passageway allowing a compensating volume of air to be sucked in from the outside atmosphere via the inside of the pump body and via the vent orifice E, as shown by the arrows in FIG.  1 B. 
     In the embodiment shown in FIGS. 2A and 2B, the pump P has no vent orifice. In which case, the frustoconical shoulder  20  is carried by a collar  2  engaged over the body C of the pump. 
     Preferably, the collar  2  comes into abutment upwards against the flange S. 
     In the variant shown, the bottom portion of the collar  2  that carries the shoulder  20  is in leaktight radial clamping engagement with the outside side wall of the body C, while the cylindrical top portion co-operates with the body C to define a gap. 
     As shown in FIG. 2B, while the pusher knob K is rising, air is drawn in via the outside of the pump body, between the ring D and the flange S, and then via the passageway opened under the shoulder  20  by the free edge  10  of the washer  1  deforming. 
     FIG. 3 shows an embodiment of the flat annular washer  1  used in the device of the invention. 
     To improve its flexibility, the washer  1  is provided with at least one slot, and with three such slots  13  in this example, which slots extend radially from the free edge  10  and facilitate elastic deformation thereof. 
     The length of the slots lies in the range one third of the width of the washer  1  to one half of the width of said washer.