Abstract: An apparatus and method for detecting overstroke, understroke and/or overspeed, underspeed conditions in vibratory equipment includes a vibratory member mounted on the equipment to vibrate therewith and to operate solid-state switches over a large number of cycles. The preferred switches are Hall effect switches operable by a magnet carried by the vibratory member. During normal vibratory motion, a normal stroke Hall effect switch resets a timing means which will operate as a missing pulse detector and will generate an abnormal pulse if it is not reset during a predetermined period of time. If the amplitude is too large, the overstroke Hall effect switch is operated and causes an abnormal condition pulse. A control circuit means is operable by an abnormal pulse to generate an alarm and/or shut down the vibrating equipment.

Abstract: A method for cleaning thermoplastic material especially for reclaiming thermoplastic material from scrap material which includes in addition to the thermoplastic material, materials having a higher melting point than the thermoplastic, such as metal, thermosetting material, etc. The scrap material which has been treated to remove large particles of metal and/or other hard materials is heated and extruded to thereby provide a confined pressurized stream of melted thermoplastic material containing therein small metallic or other unmelted particles. A portion of the stream of melted material is filtered to provide a filtrate composed of melted thermoplastic material containing therein unmelted materials having a size less than a preselected size.

Abstract: In a system for comminuting materials containing thermoplastics, the temperature in the comminuting chamber is monitored and a spray of cooling liquid is charged into the cutting chamber when the cutting chamber is at a temperature greater than the boiling temperature of the cooling liquid and less than the melting temperature for the thermoplastic being comminuted. By using heat of vaporization to extract heat from the cutting chamber, the likelihood of the plastic softening and/or melting and clogging the comminuting screen is substantially reduced. A higher throughput of materials is obtained because of material remaining harder. By vaporizing the liquid, the discharged comminuted material may be maintained very dry for later classifying. Preferably, the cooling liquid is discharged intermittently to keep the temperature of the comminuting chamber within predetermined upper and lower temperature limits.