Liquid level control device

A method of configuring a liquid level control device for location in a vessel to control a liquid level in the vessel, wherein the method comprises the steps of:

• providing a level control device, the level control device having
• a first chamber including:
• an opening to avow movement of liquid between the first chamber and the vessel;
• a vent to allow egress of air from the first chamber;
• and an inlet connectable to a liquid source;
• a first flow controller including a first float arranged in the first chamber such that the flow of liquid into the first chamber raises the first float and displaces air in the first chamber via the vent, the first flow controller including a first closure member movable to selectively close and open the inlet, the first float further arranged in the first chamber such that, in use, when the first float is at a first position when the liquid level in the first chamber is at or below a first predetermined level, the first float positions the first closure member to open the inlet to avow liquid into the first chamber via the inlet, and when the first float is at a second position when the liquid level in the first chamber is at or above a second predetermined level, the first float positions the first closure member to close the inlet to block liquid from entering into the first chamber via the inlet;
• and
• a second flow controller including a second float and further including a second closure member movable to selectively close and open the vent, the second float arranged such that, in use, when the second float is in a first position, the second float positions the second closure member to close the vent to block aft from flowing from the first chamber via the vent to escape to atmosphere, and when the second float is in a second position, the second float positions the second closure member to open the vent to allow air to flow from the first chamber via the vent to escape to atmosphere,
• wherein the first and second floats are arranged such that, in use, when the first float is in its second position and the second float is in its first position, air is trapped in the first chamber to maintain the liquid level in the first chamber at a level so as to maintain the first float in its second position, and
• wherein the second float includes a hollow body with an internal chamber for storing a substance, the hollow body configured so that the internal chamber is accessible from an exterior of the hollow body to permit addition and removal of the substance into and from the internal chamber, the second float configured to have a variable weight modifiable through selective addition and removal of the substance into and from the internal chamber,
• wherein the internal chamber of the second float is divided into a plurality of sub-chambers, each sub-chamber of the plurality of sub-chambers having a respective size corresponding to a target amount of substance to be stored in or removed from the corresponding sub-chamber to obtain a respective target change in weight of the second float;
• configuring the hollow body so that the internal chamber is accessible from the exterior of the hollow body to permit addition and removal of the substance into and from the internal chamber;
• configuring the second float to have a variable weight modifiable through selective addition and removal of the substance into and from the internal chamber;
• accessing the internal chamber from the exterior of the hollow body;
• and
• modifying the weight of the second float by adding or removing the substance into or from at least one sub-chamber of the plurality of sub-chambers in an amount corresponding to a size of the at least one sub-chamber.