| abstract |
The invention provides for a cartridge (100, 202, 202', 202", 400, 600, 800) for dispensing a fluid (104). The cartridge comprises a reservoir chamber (102) operable for receiving the fluid and for receiving a ventilation gas (106). The reservoir chamber comprises an inlet (114) for receiving the ventilation gas and an outlet (116) for dispensing the fluid. At least a portion (106) of the reservoir chamber is operable for being filled with the ventilation gas when in an operating position. The inlet is located in the portion operable for being filled with the ventilation gas. The fluid comprises a reagent. The cartridge further comprises a baffle means (108, 406, 602, 802) for restricting gas diffusion through the inlet. The reservoir chamber is operable for receiving the ventilation gas via the baffle means. The inlet is operable for maintaining a constant gas pressure within the portion of the reservoir chamber that is operable for being filled with the ventilation gas |