Low noise rotary control valve

A rotary control valve comprising:

• (a) a casing defining a receptacle having a main axis and having flow ports communicating with said receptacle at spaced points to define a flowway therethrough disposed at an acute angle to said main axis;
• (b) a flow-control member rotatably disposed within said receptacle, said member comprising:
• (1) a body shaped to fit said receptacle and having an axis of rotation coaxial with said main axis;
• (2) said body defining an axial bore having an axis generally at said acute angle with respect to said axis of rotation, and said bore opening through the outer wall of said body, whereby the opposite open ends of the bore will be in register with said flow ports at the fully-open position of said control member, and a chamber in said body surrounding said bore;
• (3) a pair of elongated orifice slots through the wall of said body extending circumferentially of the body in opposite directions generally from the opposite open ends of said bore, each of said slots being defined by walls converging toward their trailing ends;
• (4) said body having nonslotted closure portions between the trailing ends of said orifice slots and the adjacent ends of said bore, said closure portions being adapted to close off said flow ports in the flowway-closing position of said control member;
• (5) said orifice slots and said bore cooperating with the related flow ports to provide a variable-area orifice depending on the angular positions of said flow-control member;
• and
• (6) silencing means in said chamber producing a noise-attenuating effect on fluid flowing through said valve.

In a rotary control valve comprising:

• (a) a casing defining a receptacle having a main axis and having flow ports communicating with said receptacle at spaced points to define a flowway therethrough;
• (b) a flow-control member rotatably disposed within said receptacle, said member comprising:
• (1) a body shaped to fit said receptacle;
• (2) said body defining an axial bore opening through the outer wall of said body, whereby the opposite open ends of the bore will be in register with said flow ports at the fully-open position of said control member;
• (3) a pair of elongated orifice slots through the wall of said body extending circumferentially of the body in opposite directions generally from the opposite open ends of the wall of said bore, each of said slots being defined by walls converging toward their trailing ends;
• (4) said body having nonslotted closure portions between the trailing ends of said orifice slots and the adjacent ends of said bore, said closure portions being adapted to close off said flow ports in the flowway-closing position of said control member, the improvements wherein:
• (5) said body having a silencing chamber surrounding the wall of said bore, and silencing means in said silencing chamber.