Abstract: A discharge muffler for a fluid pump is formed by a cowling and a muffler insert configured to be removably inserted into a muffler receptacle of the cowling. The muffler insert includes a muffler inlet, a muffler outlet, and a plurality of muffler walls. The pump includes a pumping stage, a motor, and a drive shaft coupled between the pumping stage and the motor. When the muffler insert is inserted into the muffler receptacle, the muffler inlet communicates with the pumping stage, and the cowling and the muffler insert cooperatively define the discharge muffler. The discharge muffler is configured or effective to suppress noise generated by fluid discharged from the pumping stage.

Abstract: A fluid pump includes a pump head and a motor coupled by a drive shaft. The pump head includes a pump inlet, a pump outlet, and a pumping stage in which a movable pump element is driven by the drive shaft. The motor includes a motor rotor and a motor stator. A connector couples the motor rotor and the drive shaft. The connector includes a plate rotatable with the drive shaft, fan blades attached to the plate for establishing a flow of air for cooling the motor, and one or more counterweights attached to the plate for reducing or eliminating imbalance created by certain forces generated by the pump during operation.

Abstract: A vacuum pump isolation (VPI) valve is interposed between a vacuum pump and a vacuum chamber. During normal operation of the vacuum pump, the VPI valve is open, allowing fluid communication between the vacuum pump and the vacuum chamber. When the vacuum pump becomes non-operational such as by losing power, the VPI valve closes, thereby isolating the vacuum chamber from the vacuum pump. The closing of the VPI valve is driven by the exhaust gas pressure of the vacuum pump. The VPI valve becomes exposed to the exhaust gas pressure by the opening of a pilot valve, which may occur as a result of the vacuum pump ceasing to operate. By this configuration, the VPI valve is hermetic and does not require ambient air for its operation.