Patent ID: 7529075

Claim:
A system for providing an electric field comprising: an electrically insulated frame having a rectangular top, a rectangular bottom, rectangular opposing sides and rectangular opposing ends, the sides extending between the top and the bottom, each of the ends engaging the top, the bottom and the sides, the frame defining an interior; guard members suspended within the interior of the frame, each of the guard members being formed of metal tubing exhibiting a circular cross section, the tubing being shaped such that each of the guard members is rectangular, the guard members being spaced from each other and located along a length of the frame such that the guard members are oriented substantially parallel to the ends of the frame; and metal endplates positioned such that a first of the endplates is located at a first of the ends and a second of the endplates is located at a second of the ends; wherein the frame, guard members and endplates are operative to form an electric field within the interior of the frame responsive to an electric potential being applied to at least one of the endplates and the guard members.