Noiseless air-actuated turbine-type vibrator with muffler

A relatively silent, compressed gas-actuated, turbine-type vibrator having a rotor of not less than 1-1/4 inches and not more than 51/2 inches diameter and when operated within a speed range of 6,000 to 10,000 rpms having a noise level not greater than 75 decibels hz., the vibrator including:

• (a) a substantially closed housing having a cylindrical chamber therein;
• (b) a dynamically unbalanced rotor freely rotatable in the cylindrical bore of the chamber, the diameter and length of the rotor being established so that not less than 1/32 of an inch clearance is provided between the rotor and ends and bore of the chamber, the rotor having a plurality of tooth-like configurations formed on its outer periphery, the tooth-like configuration further having a depth which corresponds to a distance not exceeding 7 percent and not less than 11/2 percent of the diameter of the rotor;
• (c) an air outlet formed in the housing and extending from the rotor chamber to the outside of the housing;
• (d) an air inlet formed in the housing and extending from the outside of the housing to the rotor chamber, the air inlet arranged to direct the incoming pressurized air tangentially against the teeth of the mounted rotor and with the tooth-like configuration so formed that in a plane normal to the axis of the rotor the face of the tooth-like configuration against which the incoming air impinges defining an angle of intersection with a theoretical radial line of said rotor, said defined angle being as little as zero and as great as 30.degree. as measured from said point of intersection and inclined in such a direction that the circumferential thickness of the tooth-like configurations tend to decrease as the radial distance from the axis increases, the cross-sectional area of the inlet being 30 to 55 percent of the area of the outlet diameter;
• (e) a muffler housing carried by the turbine housing and providing an attached muffler chamber, said muffler housing having an inlet side connected to the chamber outlet and on a side opposite the inlet side into the muffler housing there is provided a closure plate having an outlet leading substantially directly to atmosphere, and (f) a porous muffler member carried in the muffler housing, this muffler member constructed so as to provide myriad paths for the effluent air while flowing through the muffler housing to its discharge from this muffler housing.