| 摘要 |
<p>An apparatus for maintaining a substantially constant predetermined pressure in a pressurized container (10) for dispensing product contained in the container at the substantially constant pressure comprises a container (10), a vessel (32) containing pressurised gas in the container (10), and a cylinder (36) in the vessel (32) and defining with said vessel a chamber (38) containing the pressurised gas. A piston (40) in the cylinder (36) is exposed to the pressure in the container (10) for moving between first and second positions relative to the cylinder (36). Communication means (36a, 36b, 42, Fig. 2A) is responsive to such movement for selectively permitting the pressurized gas to pass from the chamber (38) to the container (10). Two openings (32d, 16a) are provided respectively in the vessel (32) and the container (10), and a tube (54) connects the openings to permit pressurized gas to be introduced through the container (10) into the chamber (38). <IMAGE></p> |
