| 摘要 |
Improved dispensing devices (100) and methods are provided that include a hollow barrel (102) containing the composition to be dispensed along with a piston (120, 220, 320, 420) received in one end (104) of the barrel (102) for dispensing the composition from the opposite end (106) of the barrel (102). At least one tortuous groove (200, 202, 204, 226, 326, 426, 436) extends across the side of the piston (120, 220, 320, 420) and communicates with the exterior of the barrel (102). The groove (200, 202, 204, 226, 326, 426, 426, 436) allows both air and the composition to travel along the side of the piston (120, 220, 320, 420) as the piston advances into the barrel (102). By permitting passage of both air and the composition, the groove (200, 202, 204, 226, 326, 426, 436) eliminates air pockets in the composition while alleviating pressure in the barrel (102) as the piston (120, 220, 320, 420) advances. |
| 主权项 |
1. A device for dispensing a composition comprising:
a hollow barrel including an inner surface, open front end and an open back end; a piston having shape complemental to the inner surface and received in the back end of the barrel to present a chamber located between the piston, the inner surface and the front end of the barrel, wherein the piston comprises a cylindrical body having a surface; two or more grooved regions, each of the two or more grooved regions having a tortuous groove located on the surface of the cylindrical body of the piston and extending along the inner surface of the barrel, where the two or more grooved regions are spaced apart from each other in directions parallel to a longitudinal axis of the cylindrical body to form an annular cavity between the cylindrical body of the piston and the inner surface of the barrel that extends between the two or more grooved regions, wherein the tortuous groove of each of the two or more grooved regions communicates with both the chamber and the back end of the barrel when there is zero pressure differential between the chamber and the back end of the barrel and further wherein the tortuous groove of each of the two or more grooved regions is sized to allow the composition to travel along the tortuous groove as the composition is being dispensed; and one or more additional tortuous grooves adjacent the tortuous groove of each of the two or more grooved regions to form a plurality of grooves that are parallel and coincident with each other. |
