Abstract: A screen assembly for a vibratory screening machine including a frame in the nature of a plate having spaced apertures therein, spaced frame members on opposite sides of the apertures, a screen formed in an undulating shape having substantially parallel ridges with downwardly sloping sides, troughs formed between the downwardly sloping sides for conducting material which is being screened, undersides on the troughs, bonds for securing the undersides of the troughs to the spaced frame members which are located on opposite sides of the apertures, and channels at the sides of the plate for securing the frame to a vibratory screening machine.

Abstract: A screening screen assembly for a vibratory screening machine including an apertured plate, and a bonded subassembly of an undulating support screen and fine screening screen and finer screening screen bonded to each other by a fused plastic grid and bonded to the apertured plate. A method of fabricating a screening screen assembly for a vibratory screening machine including the steps of providing a support screen, superimposing a plastic grid onto the support screen, superimposing a finer screening screen onto the fine screening screen, applying heat and pressure to the superimposed screens to fuse the plastic grid and thereby form a flat bonded laminate subassembly by causing the fused plastic grid to permeate the fine screen and the finer screen and the support screen, forming the bonded laminate subassembly into an undulating shape, providing an apertured plate, and bonding the undulating bonded subassembly to the apertured plate.

Abstract: A screening screen assembly for a vibratory screening machine including an apertured plate, and a bonded subassembly of an undulating support screen and fine screening screen and finer screening screen bonded to each other by a fused plastic grid and bonded to the apertured plate. A method of fabricating a screening screen assembly for a vibratory screening machine including the steps of providing a support screen, superimposing a plastic grid onto the support screen, superimposing a finer screening screen onto the fine screening screen, applying heat and pressure to the superimposed screens to fuse the plastic grid and thereby form a flat bonded laminate subassembly by causing the fused plastic grid to permeate the fine screen and the finer screen and the support screen, forming the bonded laminate subassembly into an undulating shape, providing an apertured plate, and bonding the undulating bonded subassembly to the apertured plate.

Abstract: A quick release draw bolt device including a bolt member, an end on the bolt member for exerting a pulling force on an external member, first and second body members mounted on the bolt member, a cam arrangement between the first and second body members for causing them to occupy relatively close and relatively remote positions relative to each other, and a spring arrangement mounted relative to the first and second body members for causing the bolt member to exert a pulling force when the first and second body members are in a relatively remote position and for releasing the pulling force when the first and second body members are in a relatively close position. An alignment structure for the screen of a vibratory screening machine including a notch on the channel end of a screen and a cooperating tab on the drawbar which engages the channel. A balloon seal for attachment to the edge of a vibratory screen for sealing the space between the edge and the bed of the machine.

Abstract: A screen assembly for a vibratory screening machine including a frame, and a screen cloth on the frame having wires with a diameter D of between about 1.6.times.10.sup.3 micrometers and 17.8 micrometers with a peak to valley roughness R in micrometers which is between about R=0.333D and R=0.05D. A screen cloth for mounting on the frame having a range of dimensions as set forth above. A method of making a screen for a vibratory screening machine including the steps of providing a screen cloth having a wire of a diameter D of between about 1.6.times.10.sup.3 micrometers and 17.8 micrometers and roughing the surface of the wires to a peak to valley roughness which is between about R=0.333D and R=0.05D.

Abstract: A vibratory screen for a vibratory screening machine consisting of a plate having a plurality of spaced openings therein, a coarse screen located in contiguous relationship to the plate, a fine screen on top of the coarse screen, a finer screen on top of the fine screen, and a topmost screen which is less fine than the finer screen and epoxy binding all of the foregoing screens to the plate at the borders of the openings. A vibratory screening machine having a tank for receiving a liquid-solid mixture, a plurality of screens of the foregoing type mounted to produce a sealed partition in the tank, an inlet conduit for supplying a liquid-solid mixture to the screens at a rate to maintain a head of the liquid-solid mixture above the screens, a vibratory motor attached to the tank to vibrate the tank, an outlet in the tank below the screens, and a liquid trap located at the outlet to thereby prevent air from entering the chamber in the tank below the screens and to draw a slight vacuum in the chamber.