Positive displacement multichamber pump dispenser

摘要

The positive displacement pump delivers the products uniformly and with a low force to actuate the pump. The uniform delivery results from a close slideable fitting of the upper part into the lower part. A low force to actuate is accomplished in part by reduced surface area contact of the upper portion and lower portion during slideably interfitting operation. This is accomplished preferably by having transverse ribs on the exterior surface of the upper part and longitudinal ribs on the interior surface of the lower part. As a result the contact of the upper part and lower part during use is a transverse rib/longitudinal rib contact. The longitudinal ribs preferably are parallel to the vertical axis of the base with no draft angle. Further, there is a locking mechanism between the an upper part shroud and rams located in the lower part. The locking mechanism controls the movement of the reusable shroud. The locking mechanism is comprised of at least one arm on a lower part of the upper shroud, this at least one arm contacting the upper region of at least one of the rams of the lower part. Additionally there are reinforcing ledges on the lower region of the upper shroud and on the upper region of the lower shroud. The reinforcing ledge on the upper shroud can extend to comprise a floor on the upper shroud. Yet further the spout of the dispenser has a structure where the region of narrowest cross-section is intermediate the ends of the spout. This structure decreases the drag on the material flowing through the spout and thus further decreases the force to actuate the pump.