Abstract: A hydrocyclone assembly suitable for use with high temperature feeds (e.g., hot petroleum liquids). The hydrocyclone body is made of ceramic material with one end being flanged and cooperating with an inlet head. These parts are clamped against a mounting plate by means including one or more spring members of the distorted washer type (e.g., Belleville washer). The mounting minimizes breakage of the hydrocyclone body when used with high temperature fluid feed. Some embodiments employ a plurality of hydrocyclones disposed within a common pressure vessel.