US Patent 8734139 Pumps and pump heads comprising volume-compensation feature

A fluid pump having a pump housing that includes at least one expansion joint, provides volume compensation, as needed, to adjust for changes in pressure in the pump housing. Various embodiments automatically and passively reduce static pressure in the pump housing associated with a freezing event, thereby preventing damage to the pump head. Volume compensation is achieved by employing, in each expansion joint, a dynamic seal that allows relative movement of two portions of the pump housing, and a bias that provides a selected counter-force to the movement of the housing portions. The subject pumps are particularly suited for use in automotive and other rugged applications, in which fluid pumps may experience recurring freezing events.