Fluid product dispensing pump

Information

  • Patent Grant
  • 6811060
  • Patent Number
    6,811,060
  • Date Filed
    Tuesday, April 1, 2003
    21 years ago
  • Date Issued
    Tuesday, November 2, 2004
    19 years ago
Abstract
A fluid dispenser pump comprising a pump body (10) containing a pump chamber (11) defined between an upper piston (20) and a lower piston (30), the pistons (20, 30) being mounted to slide in leaktight manner in the pump body (10), the pump chamber (11) being provided with an inlet valve (40) and with an outlet valve (50), the lower piston (30) co-operating with the outlet valve (50), when the full dose has been metered out, to open the outlet valve and to make it possible to deliver the fluid contained in the pump chamber (11), the dispenser pump being characterized in that the lower piston (30) is separate from the inlet valve seat (42) and is mounted to float in the pump chamber (11), the lower piston (30) being returned to its rest position by the inlet valve seat (42).
Description




The present invention relates to a fluid dispenser pump.




Fluid dispenser pumps are well known from the state of the art. Such a pump generally comprises a pump body which defines a pump chamber disposed between an inlet valve and an outlet valve, with a piston sliding in said pump body to deliver fluid contained in said pump chamber. In certain cases, the pump can have two pistons, namely an upper piston and a lower piston, which pistons slide together in the pump body while it is being actuated, until the outlet valve opens and the fluid contained in the pump chamber is delivered.




In certain cases, in particular with pharmaceuticals, dose-metering accuracy and guaranteed dispensing of a full dose each time the pump is actuated can be essential criteria. In particular, it is important to prevent incomplete doses from being dispensed, and to prevent the pump chamber from being filled in part only after said pump has been actuated.




An object of the present invention is to provide a fluid dispenser pump that guarantees dose-metering accuracy each time the pump is actuated, and that guarantees a full dose is dispensed.




Another object of the present invention is to provide such a fluid dispensing pump that is simple and inexpensive to manufacture and to assemble.




To these ends, the present invention provides a fluid dispenser pump comprising a pump body containing a pump chamber defined between an upper piston and a lower piston, said pistons being mounted to slide in leaktight manner in said pump body, said pump chamber being provided with an inlet valve and with an outlet valve, said lower piston co-operating with said outlet valve, when a full dose has been metered out, to open said outlet valve and to make it possible to deliver the fluid contained in the pump chamber, said dispenser pump being characterized in that the lower piston is separate from the inlet valve seat and is mounted to float in the pump chamber, said lower piston being returned to its rest position by said inlet valve seat.




Advantageously, the outlet valve comprises a valve member which is mounted to move in the pump chamber and which is urged into its closure position by pressure from the fluid contained in the pump chamber, said moving valve member being provided with a shoulder which, when a full dose has been metered out, co-operates with said lower piston or with an element integral therewith, so that the lower piston lifts the valve member off its valve seat so as to open the outlet valve.




Advantageously, the outside diameter of the upper piston is larger than the outside diameter of the lower piston.




Advantageously, the valve seat of the inlet valve is urged by a resilient element such as a spring into the rest position of the pump, in which position said lower piston or an element integral therewith urges the outlet valve into its closure position.




Advantageously, the lower piston acts as a primer element for removing the air contained in the pump chamber when the pump is actuated for the first time.




Advantageously, when the pump chamber contains air, an air removal passageway is formed between the lower piston, the upper piston and the inlet valve seat so as to enable the air to be removed from the pump chamber, said lower piston closing off said air passageway in leaktight manner when the pump chamber contains fluid to be dispensed.




Advantageously, the outlet valve member is provided with a second shoulder which co-operates with said lower piston or with an element integral with said lower piston, when the pump is in the rest position, so that the lower piston urges said moving valve member into its closure position.











Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description given with reference to the accompanying drawings which are given by way of non-limiting example and in which:





FIG. 1

is a diagrammatic section view of a pump of an advantageous embodiment of the present invention, in the rest position;





FIG. 2

is a view similar to the view in

FIG. 1

, in the priming position; and





FIG. 3

is a view similar to the view in

FIGS. 1 and 2

, just before the fluid contained in the pump chamber is delivered.











With reference to the figures, the pump comprises a pump body


10


in which an upper piston


20


and a lower piston


30


are mounted to slide in leaktight manner. Between said pistons


20


and


30


a pump chamber


11


is defined that is provided with an inlet valve


40


and with an outlet valve


50


. The inlet valve


40


may be a ball valve comprising a ball


41


co-operating with a corresponding valve seat


42


. When the user actuates the pump, the two pistons


20


and


30


slide inside the pump body while closing the inlet valve


40


until the outlet valve


50


opens to enable the fluid to be delivered.




In the invention, the lower piston


30


, or an element


70


integral therewith, co-operates with the outlet valve


50


to open it when a full dose has been metered out. A dose might not be metered out in full until the end of the actuating stroke of the lower piston


30


, but it is also possible for a full dose to be metered out before said end of the actuating stroke. In which case, the outlet valve


50


opens before the lower piston has traveled over its full stroke. In particular, in the example shown in the figures, the outlet valve


50


includes a moving outlet valve member


51


which is mounted to move axially inside the pump chamber


11


, said moving valve member


51


being urged into its closed position, in which it presses against its valve seat


52


, by the pressure from the fluid disposed inside the pump chamber


11


. This implementation guarantees excellent leaktightness at the outlet valve, because it is impossible for said outlet valve to open in undesired manner before the fluid is delivered. Said valve member


51


is advantageously provided with a first shoulder


55


which co-operates with the lower piston


30


or with an element


70


integral with said lower piston


30


, when the full dose has been metered out, so that the lower piston


30


mechanically lifts the valve member


51


off its valve seat


52


so as to open the outlet valve


50


. Advantageously, the moving valve member


51


of the outlet valve


50


is also provided with a second shoulder


56


which co-operates with the lower piston


30


or with an element


70


integral therewith, when the pump is in the rest position, so that the moving valve member


51


is urged towards it closed position.




Operation of the pump is described below with reference to

FIGS. 1 and 3

.




In

FIG. 1

, the pump is in the rest position. When the user actuates the pump, said user exerts axial pressure on the upper piston


20


which then slides inside the pump body


10


. Since the fluid contained in the pump chamber


11


is incompressible, said fluid also causes the lower piston


30


to slide in leaktight manner inside the pump body


10


. The inlet valve


40


is urged into its closed position by the pressure from the fluid inside the pump chamber, and the same applies for the outlet valve


50


, whose moving valve member


51


is also urged into its closed position by the pressure from the fluid inside the pump chamber


11


.




When a full dose has been metered out, the position shown in

FIG. 3

is reached. Since the diameter of the lower piston


30


is smaller than the diameter of the upper piston


20


, the lower piston


30


or the element that is integral with the lower piston


30


and that is referenced


70


in the figures, moves faster than the upper piston


20


while the pump is being actuated. It thus goes from its position in which it is in contact with the second shoulder


56


, as shown in

FIG. 1

, to its position in which it comes into contact with the first shoulder


55


of the moving valve member


51


. Whereupon the lower piston co-operates with the moving valve member


51


to move it axially inside the pump chamber, by lifting it off its valve seat


52


, in order to open the outlet valve


50


and thereby enable the fluid contained in the pump chamber


11


to be delivered. The gap between the shoulders


55


and


56


determines the time of opening of the outlet valve, and thus the volume of the dose to be dispensed. It is necessary merely to modify said gap in order to cause the volume of the dose to vary. The present invention thus makes it very simple and very inexpensive to vary the volume of the dose to be dispensed, merely by modifying a single part of the pump.




As shown in the figures, the inlet valve


40


of the pump chamber


11


includes a valve seat


42


floatingly mounted inside the pump body


10


and urged by a spring into its rest position shown in FIG.


1


. The spring


60


is the return spring of the pump. Advantageously, the lower piston


30


is provided with a shoulder which co-operates with said seat of the inlet valve


42


so that, when the outlet valve is opened, the fluid contained in the pump chamber


11


is delivered by means of said lower piston


30


, which is returned into its starting position by the spring


60


which acts on the valve seat


42


.




In the invention, the lower piston


30


is made separately from the inlet valve seat


42


. The advantage of making the lower piston


30


separately is described below with reference to FIG.


2


and in relation to a particular embodiment of the invention.




When the outlet valve


50


is opened, the fluid contained in the pump chamber


11


is thus delivered from said pump chamber, the lower piston rising inside the pump body


10


under drive from the compressed spring


60


until the lower piston


30


, or the piece


70


integral with said lower piston


30


, comes into abutment again against the second shoulder


56


of the moving valve member


51


of the outlet valve


50


so as to urge said valve member into its closed position. The suction generated in the pump chamber by the fluid being delivered and by the pistons rising opens the inlet valve


40


, said ball thus being lifted off its valve seat to enable a new dose of fluid to be sucked into the pump chamber


11


.




The invention thus offers two essential advantages. Firstly it guarantees that a dose is delivered in full each time the pump is actuated, by preventing any partial dispensing of the contents of the pump chamber


11


. The outlet valve


50


cannot open until a full dose has been metered out, regardless of the actuating force exerted by the user on the pump. Secondly, the accuracy of dose-metering is guaranteed by the outlet valve closing automatically after the dose has been delivered.




In the invention, the lower piston


30


is made separately from the inlet valve seat


42


. By making the lower piston


30


separately from the inlet valve seat


42


, and by mounting said lower piston


30


to float inside the pump body, it is possible to use said lower piston as a primer element. As shown in

FIG. 2

, the first time the pump is actuated, when the pump chamber


11


contains air, the lower piston


30


lifts off from the inlet valve seat


42


, because air is compressible, and it generates a passageway through which air can flow out between the lower piston


30


and said inlet valve seat


42


, thereby enabling the air contained in the pump chamber


11


to be removed. Air also flows out through a passageway between the lower piston


30


and the upper piston


20


via one or more grooves


29


provided in an end surface of the upper piston


20


, and which co-operate(s) with the lower piston


30


at the end of the stroke traveled when the pump is actuated for the first time, as shown in FIG.


2


. The groove


29


thus co-operates with the lower piston


30


in a position which makes it possible to limit the dead volume of the pump chamber


11


so that almost all of the air contained in said pump chamber is removed in the position shown in FIG.


2


. When the user ceases to press on the pump starting from the position shown in

FIG. 2

, the entire mechanism of the pump rises under drive from the return spring


60


, so that the pump chamber fills with fluid via its inlet valve


40


. As soon as the fluid enters the pump chamber


11


, said lower piston


30


is urged automatically by the fluid into its position shown in

FIGS. 1 and 3

, in which position the lower piston


30


co-operates with the valve seat


42


so as to close off said above-mentioned passageway through which air can flow out. Whereupon, said lower piston


30


can no longer lift off from the valve seat


42


because of the presence of incompressible fluid inside the pump chamber


11


. When the pump is actuated on subsequent occasions, the lower piston


30


and the valve seat


42


then act as a one-piece unit, providing excellent leaktightness, and preventing any fluid from leaking out through the air removal passageway that serves to prime the pump. Naturally, the embodiment shown in the figures is an advantageous particular embodiment, but it is quite possible to consider providing other primer means for priming the pump, without necessarily using the lower piston for this purpose.




Other modifications may be made by the person skilled in the art without going beyond the ambit of the present invention, as defined by the accompanying claims.



Claims
  • 1. A fluid dispenser pump comprising a pump body (10) containing a pump chamber (11) defined between an upper piston (20) and a lower piston (30), said pistons (20, 30) being mounted to elide in leaktight manner in said pump body (10), said pump chamber (11) being provided with an inlet valve (40) and with an outlet valve (50), said lower piston (30) co-operating with said outlet valve (50), when the full dose has been metered out, to open said outlet valve and to make it possible to deliver the fluid contained in the pump chamber (11), said dispenser pump being characterized in that the lower piston (30) is separate from inlet valve seat (42) and is mounted to float in the pump chamber (11), said lower piston (30) being returned to its rest position by said inlet valve seat (42).
  • 2. A pump according to claim 1, in which the outlet valve (50) comprises a valve member (51) which is mounted to move in the pump chamber (11) and which is urged into its closure position by pressure from the fluid contained in the pump chamber (11), said moving valve member (51) being provided with a shoulder (55) which, when a full dose has been metered out, co-operates with said lower piston (30) or with an element (70) integral therewith, so that the lower piston (30) lifts the valve member (51) off its valve seat (52) so as to open the outlet valve (50).
  • 3. A pump according to claim 1, in which the outside diameter of the upper piston (20) is larger than the outside diameter of the lower piston (30).
  • 4. A pump according to claim 1, in which the valve seat (42) of the inlet valve (40) is urged by a resilient element (60) into the rest position of the pump, in which position said lower piston (30) or an element (70) integral therewith urges the outlet valve (50) into closure position.
  • 5. A pump according to claim 4 in which the resilient element comprises a spring.
  • 6. A pump according to claim 1, in which said lower piston (30) acts as a primer element for removing the air contained in the pump chamber (11) when the pump is actuated for the first time.
  • 7. A pump according to claim 6, in which, when the pump chamber (11) contains air, an air removal passageway is formed between the lower piston (30), the upper piston (20) and the inlet valve seat (42) so as to enable the air to be removed from the pump chamber (11) said lower piston (30) closing off said air passageway in leaktight manner when the pump chamber (11) contains fluid to be dispensed.
  • 8. A pump according to claim 1, in which the outlet valve member (51) is provided with a second shoulder (56) which co-operates with said lower piston (30) or with an element (70) integral with said lower piston (30), when the pump is in the rest position, so that the lower piston (30) urges said moving valve member (51) into its closure position.
Priority Claims (1)
Number Date Country Kind
00 13569 Oct 2000 FR
PCT Information
Filing Document Filing Date Country Kind
PCT/FR01/03257 WO 00
Publishing Document Publishing Date Country Kind
WO02/34413 5/2/2002 WO A
US Referenced Citations (4)
Number Name Date Kind
5092495 Andre Mar 1992 A
5303854 Cater Apr 1994 A
6302304 Spencer Oct 2001 B1
6698623 Petit Mar 2004 B2
Foreign Referenced Citations (1)
Number Date Country
1486392 Jun 1967 FR