Patent ID: 7048145
Filing Date: 2006-05-23
Classification: B05B

Abstract:
1. A liquid delivery apparatus comprising (i) a first vessel into which a liquid may be introduced via an inlet to partially fill the first vessel and to pressurise the liquid that partially fills the first vessel and the air that fills the remainder of the first vessel; (ii) an outlet via which said liquid may be discharged from the first vessel under the pressure of the liquid and air in the first vessel; (iii) a valve between the first vessel and the outlet to control passage of liquid from the first vessel to the outlet, said valve having (a) an opening, (b) a closure member adapted to close the opening, and (c) a biasing means, the arrangement of the components of the valve being such that the valve is normally held closed by the biasing means; (iv) a valve control mechanism for controlling the operation of the valve in response to the pressure of the liquid and air in the first vessel; (v) a means for transmitting the pressure of the liquid and air in the first vessel to a first chamber of a second vessel that includes an inner moveable wall which sub-divides the second vessel into said first chamber and a second chamber which are of variable volume depending upon the position of the said inner moveable wall in the vessel; and (vi) a means for transmitting the pressure of the air in the second chamber of the second vessel to the valve control mechanism; wherein the valve control mechanism comprises a moveable element which is capable of being acted on by the pressure of the air in the second chamber and transmitting a resultant force to the closure member of the valve in a direction to open the valve, and wherein the respective effective surface areas of the moveable element and the closure member and the force of the biasing means are chosen such that the closure member is opened when the pressure of the liquid and air in the first vessel reaches a predetermined level.