Urea solution pumps having leakage bypass

Urea solution pumps having leakage bypass flowpaths and methods of operating the same are disclosed. Certain embodiments are pump apparatuses including an inlet passage in flow communication with a source of urea solution and a pump chamber, an outlet passage in flow communication with the pump chamber and an exhaust after treatment system, a diaphragm facing the pump chamber and coupled with an actuator, a first housing member coupled with a second housing member form a seal around the pumping chamber, a leak collection chamber surrounding the seal, and a return passage in flow communication with the leak collection chamber and the inlet passage. Urea solution that leaks from the pump chamber past the seal is received by the leak collection chamber and flows through the return passage to the pump inlet passage. 本发明公开了具有泄漏旁路流道的尿素溶液泵及其操作方法。某些实施例泵装置，该泵装置包括：与尿素溶液源和泵室流通的入口通道，与泵室和排气后处理系统流通的出口通道，面向泵室并与促动器联接的隔膜，与第二壳体构件连接的第壳体构件在泵室周围形成密封，围绕该密封的泄漏收集室以及与泄漏收集室和入口通道流通的返回通道。从泵室泄漏经过该密封的尿素溶液被泄漏收集室接收且通过返回通道流至泵入口通道。