Temperature control unit and sight glass

摘要

An apparatus for indicating a fluid level in a reservoir includes a conduit for communication with a reservoir and including a sight glass. A buoyant primary float is provided within the conduit, and a stop is provided within the conduit for engaging the primary float to prevent travel of the primary float beyond an upper portion of the conduit. A buoyant secondary float in the conduit is moveable together with the primary float when the primary float is not engaged by the stop, and is moveable separately from the primary float when the primary float is engaged by the stop and a fluid level in the conduit exceeds the level of the stop such that a portion of the secondary float may travel separately within the upper portion of the conduit. The secondary float preferable includes an elongate portion that passes through an aperture in the primary float, and a buoyant upper portion that is located above the primary float and is larger than the aperture in the primary float. The secondary float also preferably includes a lower portion that is located below the primary float and is larger than the aperture in the primary float. The length of the elongate member between the upper and lower portions may be provided to correspond to a distance between a lower surface of the primary float when engaged by the stop, and a predetermined fluid level in the conduit such as the maximum fill level of the reservoir. The elongate member may also include markings calibrated to indicated a remaining fluid capacity of the reservoir relative to a predetermined capacity. A temperature control unit that includes a sight glass with the aforementioned primary and secondary floats is also disclosed.