초록 ▼

A waste recovery method for producing essentially pure thermoplastic material from waste thermoplastic material containing impurities is disclosed to be comprised of an extruder, primary and secondary filtes, and a pelletizer. In addition, a plurality of pressure sensors are provided at several poin

A waste recovery method for producing essentially pure thermoplastic material from waste thermoplastic material containing impurities is disclosed to be comprised of an extruder, primary and secondary filtes, and a pelletizer. In addition, a plurality of pressure sensors are provided at several points within the system for measuring the pressure of a flow of molten thermoplastic material therethrough. A microcomputer is coupled to the pressure sensors for determining the pressure sensed by each, the microcomputer further being coupled to a plotter for plotting the pressures. An operator, by observing a rise in the plotted pressures, is enabled to activate a filter changing system in order to replace a clogged filter with a clean filter when the pressure equals a predetermined critical pressure point indicative of a filter being substantially clogged with impurities. Thus, the impurities held by a filter are not dislodged and forced to pass through the filter due to the pressure exceeding the critical pressure point.

대표청구항 ▼

A method of removing impurities from a material comprising the steps of: pressurizing the material; filtering the pressurized material with a filter such that the impurities are retained in the filter; measuring a rate of pressure rise of the pressurized material in order to determine the time that

A method of removing impurities from a material comprising the steps of: pressurizing the material; filtering the pressurized material with a filter such that the impurities are retained in the filter; measuring a rate of pressure rise of the pressurized material in order to determine the time that the pressure reaches a predetermined critical pressure point indicative of the filter being substantially clogged; and providing a clean filter at a time related to the time that the pressure reaches said predetermined critical pressure point whereby the impurities retained in the substantially clogged filter are not forced to pass through the filter due to a further pressure rise causing the pressure to exceed the predetermined critical pressure point.