Abstract: In a valve having a plug and valve seat for controlling the flow of fluid between an inlet port and an outlet port, the plug has radial serrations on its bottom face and has a length for establishing turbulence during the last 1/4 of its stroke as the plug is lifted from the valve seat, the flow through said valve seat being modulated by the turbulence.

Abstract: An averaging temperature responsive device having a hollow elongated member, a plurality of holes substantially along the length of the member, the plurality of holes decreasing in area from the hole near the end at which the member is mounted to the hole at the other end of the member, an exhaust opening at the second end of the member for permitting air moving through the duct which enters the plurality of holes to be exhausted from the inside of the member, and a temperature responsive element for sensing the average temperature of air moving through the member.