Patent attributes
Disclosed is a dispenser for dispensing a composition in response to level changes in a liquid in a tank. The dispenser includes a container for holding the composition, a discharge conduit in fluid communication with the container, an air inlet in fluid communication with the container, and a level sensing member mounted to the dispenser such that a lower end of the level sensing member contacts the liquid in the tank and senses its level. In use, a rise of the liquid in the tank between a lower liquid level and a higher liquid level causes the level sensing member to alter air pressure in a headspace of the container above the composition and thereby cause a controlled discharge of the composition from the discharge conduit; and a fall of the liquid in the tank between the higher liquid level and the lower liquid level causes the level sensing member to alter pressure in the headspace and thereby causing air to be vented into the headspace from the air inlet.
