A mechanical pump having a unitary construction such that the fluid being pumped is prevented from leaking without requiring the use of discrete seal elements. The absence of discrete seal elements and integral coupling of various components of the pump substantially reduces the likelihood of failure of potential leak points. This allows the pump to operate continuously for a longer period and with greater reliability than previously utilized pumps. The pump can be utilized in a greater number of applications without requiring special design consideration for the fluid being pumped. The absence of discrete seal elements also reduces the cost and complexity of manufacturing the pump.