Abstract: Exemplary processing chambers may include a body having sidewalls and a bottom plate. The bottom plate may define an exhaust opening and a gas inlet. The chambers may include a faceplate seated atop the body. The chambers may include a purge ring seated atop the bottom plate. The purge ring may include a ring body having an outer edge and an inner edge defining an open interior. The ring body may have a surface disposed against the bottom plate. The ring body may define an opening aligned with the exhaust opening. The surface may define a fluid port aligned and coupled with the gas inlet. The surface may define arcuate grooves extending into the fluid port. The arcuate grooves may be parallel with the inner and outer edges. The surface may define radial grooves extending from the open interior to an arcuate groove.