Patent ID: 7201238

Claim:
A rotary jetting apparatus comprising: (a) a housing defining a fluid path for a pressurized fluid; (b) a rotor, at least a portion of which is disposed coaxially within the housing, the rotor including a proximal end and a distal end, the rotor being configured to rotate relative to the housing, a distal surface of the rotor sealingly engaging the housing; (c) at least one nozzle in fluid communication with the fluid path, the at least one nozzle being disposed proximate the distal end of the rotor and being configured to rotate in unison with the rotor, and to discharge a jet of the pressurized fluid; (d) a seal head disposed within the housing adjacent to the proximal end of the rotor, so that the seal head does not rotate relative to the housing, the seal head including a distal face that sealingly engages the proximal end of the rotor; (e) at least one of an upper mechanical face seal and a lower mechanical face seal; and (f) a volume disposed adjacent to one of the upper mechanical face seal and the lower mechanical face seal, the volume being coupled to a pressure at startup that reduces an amount of torque required to initiate rotation of the rotor, by reducing a friction acting on the rotor.