Abstract: A float valve for controlling a liquid level includes a valve main body which forms a throughflow duct, a valve narrowing which is formed by the throughflow duct, and a float mounted above the valve narrowing as a valve element. The valve element is freely movable, closes the valve narrowing via its weight, and is lifted from a valve closing position via a liquid. The float has a low center of gravity so that the float always rights itself to a standing position.

Abstract: A closure plug of a battery includes an external thread for installing into an opening of a battery cover, and at least one gas-tight seal arranged on an outer side of the closure plug. The at least one gas-tight seal includes a mixture of polypropylene or polyethylene and polyisobutylene.

Abstract: A water-refill plug for automatically filling and refilling the cells of the battery has a housing forming a valve seat, and forming an upper and lower guides above and below the valve seat. A float is movable vertically in the housing below the seat in one of the cells of the battery. A valve body vertically movable independently of the float body has upper and lower end vertically slidable in the upper and lower guides. A magnetically attractable or repellable element or permanent magnet is provided on one of the bodies. Another permanent magnetic on the other of the bodies exerts a force via the element or magnet so the valve body is moved by the float body.

Abstract: A float valve for controlling a liquid level includes a valve main body which forms a throughflow duct, a valve narrowing which is formed by the throughflow duct, and a float mounted above the valve narrowing as a valve element. The valve element is freely movable, closes the valve narrowing via its weight, and is lifted from a valve closing position via a liquid. The float has a low center of gravity so that the float always rights itself to a standing position.

Abstract: The invention relates to a rechargeable battery in one or more cells and a space disposed above the electrodes and enclosed by the battery cover, wherein at least the space above the battery is partially or completely filled by an open-pore foam and/or a material having a honeycomb structure.