Manual pump

Abstract

A manual pump (P) having a pump body (B) defining a slide cylinder (F) for a piston (K) secured to an actuator rod (S); a pump chamber (C) and an outlet valve (V) arranged between the pump chamber (C) and a dispenser orifice (O) so as to dispense the fluid from the pump chamber (C). The pump includes an inlet valve ( 2, 12 ) arranged between the pump chamber (C) and an inlet (I) of the pump (P) to take the fluid into the pump chamber (C) from the reservoir (R), the inlet valve having a movable member ( 2 ) that selectively bears against a valve seat ( 12 ), a return passage ( 23 ) enabling a fraction of the fluid that is put under pressure in the pump chamber (C) to escape therefrom without passing via the outlet valve (V). The return passage ( 23 ) creates a lack of sealing at the inlet valve.

The invention claimed is: 
     
       1. A manual pump for a fluid dispenser, the pump being for associating with a fluid reservoir, thereby forming a fluid dispenser, the pump comprising a pump body that defines a slide cylinder for a piston that is secured to an actuator rod, the pump further comprising a pump chamber in which a dose of fluid is put under pressure on each actuation, the pump further comprising an outlet valve that is arranged between the pump chamber and a dispenser orifice so as to dispense the fluid from the pump chamber, the pump further comprising an inlet valve that is arranged between the pump chamber and an inlet of the pump so as to take the fluid into the pump chamber from the reservoir, the inlet valve comprising a movable member that selectively bears against a valve seat, a return passage enabling a fraction of the fluid that is put under pressure in the pump chamber to escape therefrom without passing via the outlet valve; the return passage creating a lack of sealing at the inlet valve;
 the manual pump being characterized in that the return passage is formed by the inlet valve, such that the inlet valve is thus leaky. 
 
     
     
       2. A manual pump according to  claim 1 , wherein the return passage is formed by the movable member. 
     
     
       3. A manual pump according to  claim 1 , wherein the return passage comprises at least one groove that is formed where the movable member comes into contact with its valve seat. 
     
     
       4. A manual pump according to  claim 1 , wherein the return passage comprises a hole passing through the movable member that is advantageously in the shape of a disk. 
     
     
       5. A manual pump according to  claim 1 , wherein the return passage is formed by the valve seat, in particular in the form of at least one slot. 
     
     
       6. A manual pump according to  claim 1 , wherein an additional return passage is formed by the pump body. 
     
     
       7. A manual pump according to  claim 6 , wherein the additional return passage comprises a direct borehole that passes through the wall thickness of the pump body and connects the pump chamber directly to the reservoir. 
     
     
       8. A manual pump according to  claim 6 , wherein the pump body includes a dip tube that is connected to the inlet of the pump, the additional return passage comprising a bypass that connects the pump chamber to the dip tube without passing via the inlet valve. 
     
     
       9. A manual pump according to  claim 8 , wherein the pump includes an outer sheath that surrounds the pump body, the bypass extending, in part, between the pump body and the outer sheath and advantageously comprising at least one inner borehole that passes through the wall thickness of the pump body. 
     
     
       10. A manual pump according to  claim 6 , wherein the additional return passage is formed in the slide cylinder. 
     
     
       11. A manual pump according to  claim 1 , wherein about 50% to 90% of the dose of fluid that is put under pressure in the pump chamber (C) escapes through the return passage ( 23 ;  33 ,  34 ;  43 ;  151 ). 
     
     
       12. A manual pump according to  claim 6 , wherein about 50% to 90% of the dose of fluid that is put under pressure in the pump chamber escapes through the return passage, and possibly through the additional return passage. 
     
     
       13. A manual pump according to  claim 1 , wherein the return passage presents a single or combined section lying in the range about 0.03 mm 2  to 0.5 mm 2 , with a preferred section of about 0.1 mm 2 . 
     
     
       14. A manual pump according to  claim 6 , wherein the return passage, and possibly the additional return passage, present(s) a single or combined section lying in the range about 0.03 mm 2  to 0.5 mm 2 , with a preferred section of about 0.1 mm 2 . 
     
     
       15. A fluid dispenser comprising a fluid reservoir on which there is mounted a manual pump according to  claim 1 , the return passage enabling a fraction of the fluid that is put under pressure in the pump chamber to be returned directly or indirectly to the fluid reservoir.