Abstract: Homogenizing apparatus having a stack of disc valves made of stainless steel having a Brinell hardness from 40-42. A hydraulic actuator for applying a force to the stack of disc valves is spaced above the valve disc housing, the space therebetween being vented to the atmosphere to prevent hydraulic leakage into the valve housing. The disc valves are maintained in stacked relationship by stainless steel rods having their lower ends welded to a bottom plate supporting the stack of valve discs. To enhance the washing and cleaning of the apparatus radii are provided on all of the corners of the fluid contacting components which have angles less than 135.degree..