초록 ▼

The present invention relates to a granular-material dehumidification plant including at least one silo or hopper arranged to receive granular material to be dehumidified at the top thereof and provided with a controlled lower delivering mouth, at least one feeding duct designed to be dipped in the

The present invention relates to a granular-material dehumidification plant including at least one silo or hopper arranged to receive granular material to be dehumidified at the top thereof and provided with a controlled lower delivering mouth, at least one feeding duct designed to be dipped in the granular material contained in each hopper to supply hot and dry processing air thereto, and at least one exhaust duct for humid processing air; at least two molecular sieve towers arranged alternatively to supply hot and dry processing air to the at least one hopper, each tower delimiting therein a space for housing molecular sieves and a chamber for housing heating means, the space and the chamber being in fluid communication with one another at one end thereof, while being in fluid communication at the other end thereof, with a respective air inlet/outlet duct.

대표청구항 ▼

The invention claimed is: 1. A granular-material dehumidification plant including at least one silo or hopper arranged to receive granular material to be dehumidified at the top thereof and provided with a controlled lower delivering mouth, at least one feeding duct designed to be dipped in the gra

The invention claimed is: 1. A granular-material dehumidification plant including at least one silo or hopper arranged to receive granular material to be dehumidified at the top thereof and provided with a controlled lower delivering mouth, at least one feeding duct designed to be dipped in the granular material contained in each hopper to supply hot and dry processing air thereto, and at least one exhaust duct for humid processing air; at least two molecular sieve towers arranged alternately to supply hot and dry processing air to said at least one hopper, each tower delimiting therein a space for housing molecular sieves and a chamber for housing heating means, said space and said chamber being in fluid communication with one another at one end thereof, while being in fluid communication, at the other end thereof, with a respective air inlet/outlet duct; air pressurizing or pumping means arranged to receive, at the suction (inlet) side thereof, humid processing air from a respective exhaust duct, and to feed pressured air, at the delivery side thereof, to each molecular sieve tower; switching-shunting means located between the delivery of said pressurizing means and said inlet/outlet ducts of said housing spaces for molecular sieves thereby switching at least one of said molecular sieve towers between a processing step and a regeneration step; and a programmable electronic control unit, wherein it comprises pressurizing valve means located between said inlet/outlet ducts of said housing chamber of said heating means for each molecular sieve tower and arranged to ensure a minimum pressure within a tower during a regeneration step, and temperature detecting means electrically connected to an input of said programmable electronic control unit. 2. A plant as claimed in claim 1, wherein said pressurizing valve means comprises an inner chamber in direct fluid communication with said inlet/outlet ducts and with an outlet to at least one feeding duct through an opening controllable by shutter means, whereby being controllably opened/closed as a function of the pressure within said inner chamber. 3. A plant as claimed in claim 2, wherein said shutter means is supported by a rod or pin slidingly mounted in a substantially vertical direction in said inner chamber, thereby being opened and closed by gravity owing to air pressure variations in said chamber. 4. A plant as claimed in claim 3, wherein said shutter means is resiliently loaded in a controlled way, thereby opening and closing proportionally to the pressure within said inner chamber. 5. A plant as claimed in claim 1, comprising cutting off means which is in communication with at least one exhaust duct from said switching-shunting means, and controllable by a detecting means designed to detect pressure differential between suction side and delivery side of said pressurizing means. 6. A plant as claimed in claim 5, wherein that said cutting off means comprises a diaphragm valve, whose diaphragm delimits two inner compartments, a compartment communicating with at least one exhaust opening, whereas the other is in fluid communication with said pressure differential detecting means. 7. A plant as claimed in claim 5, wherein said pressure differential detecting means comprises a solenoid valve having two inlets in fluid communication with said suction side and said delivery side, respectively, of said air pressurizing means, and its outlet in fluid communication with said compartment. 8. A plant as claimed in claim 5, wherein said switching-shunting means comprises a slide valve assembly, and driving means for said slide valve assembly designed to drive it both in a continuous and pulsating way. 9. A plant as claimed in claim 6, wherein said slide valve assembly comprises a valve body delimiting therein two side chambers and an intermediate chamber which communicate with each other through openings, said intermediate chamber communicating with the delivery side of said air pressurizing or pumping means, whereas said side chambers communicate with both a respective air inlet/outlet duct and a respective exhaust opening to said cutting off means, and a rigid rod, which extends through said side and intermediate chambers, supports a pair of shutter means fixed thereto and designed to open-close said openings, and extends outwardly from the valve body thereby operatively engaging with said driving means. 10. A plant as claimed in claim 9, wherein said driving means comprises a reversible linear actuator means including a reversible electric motor controllable by an electronic program control unit and a reducer, and a rack operatively connected to said reducer and rigid with said rod. 11. A plant as claimed in claim 10, wherein said linear actuator means comprises two spaced stops secured to said rigid rod, a resilient loading means for each stop arranged to abut against a fixed member with respect to said rigid rod, a pair of micro-switches carried by the rigid rod and designed to abut against an intermediate contact fixed with respect to the rigid rod and arranged to stop said reversible motor at two working positions of said shutters. 12. A plant as claimed in claim 1, comprising cooling means designed to cool the air flowing through said at least one exhaust duct for humid processing air fed to said air pressurizing means. 13. A plant as claimed in claim 12, wherein said cooling means comprises an assembly of pipes connected in parallel to each other and subject to the action of at least one fan means drivable by a respective electric motor. 14. A plant as claimed in claim 1, comprising a heat sensing probe arranged to detect the temperature of the air coming out of a regeneration tower, and electrically connected to said electronic program control unit. 15. A plant as claimed in claim 1, wherein said electronic program control unit comprises a first memory portion designed to store processing parameters concerning a first multiplicity of granular materials, and a second memory portion designed to store processing parameters of experimental materials. 16. A plant as claimed in claim 1, comprising a user interface with said electronic program control unit. 17. A plant as claimed in claim 16, wherein said user interface comprises a display unit, and data input means for applying data to said electronic program control unit. 18. A plant as claimed in claim 17, wherein said display unit is of touch-screen type. 19. A plant as claimed in claim 1, comprising adjusting means controlled by said electronic program control unit and designed to adjust the flow-rate of the air coming out of said pressurizing and pumping means. 20. A plant as claimed in claim 19, wherein said adjusting means for the flow-rate of the air coming out of said pressurizing and pumping means comprises an inverter. 21. A plant as claimed in claim 1, comprising sensing means for measuring the air flow-rate entering the hopper which is electrically connected to said electronic program control unit. 22. A plant as claimed in claim 21, wherein said flow-rate measuring means comprising a Venturi tube. 23. A method for regenerating one molecular sieve tower in a dehumidifying plant for granular material as claimed in 1, comprising, in sequence, heating molecular sieves to a temperature of about 300 degrees C., and cooling said molecular sieves, characterized in that said cooling comprises controllably mixing air in the tower to be cooled by means of processing air coming from another molecular sieve tower, said mixing being controlled by said switching-shunting means in response to the temperature detected by said temperature detecting means. 24. A method as claimed in claim 23, wherein said mixing through said switching-shunting means is carried out in a gradual pulsating way. 25. A method as claimed in claim 24, wherein said tower to be cooled during the mixing step is isolated from the outside by cutting off means. 26. A method as claimed in claim 23, comprising a standby step for said tower to be cooled when cooling thereof is terminated. 27. A method as claimed in claim 23, comprising a hot and dry air flow-rate modulating step in said air pressurizing or pumping means controlled by said electronic program control unit.