Abstract: A frictional damper system particularly suited for use in preventing chatter and flutter in a liquid and two phase flow pressure relief valve. The frictional damper system includes one or more damper bodies each having a vertical through-hole and at least one inclined bore extending from the exterior of the damper body into the vertical through-hole. A friction contact member is positioned within each bore and urged inwardly by a spring device or the like. A portion of the object to be damped, such as the stem of a pressure relief valve, extends through the vertical throughhole. The type of material forming the friction member, the degree of compression by the spring device and the amount of inclination of the bore(s) is such that the vertical compression forces components of the damper spring(s) virtually negate the frictional forces created when the member to be damped moves in a first direction.