Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/06—Controlling, e.g. regulating, parameters of gas supply
  • F26B21/08—Humidity
  • F26B21/083—Humidity by using sorbent or hygroscopic materials, e.g. chemical substances, molecular sieves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B13/00—Conditioning or physical treatment of the material to be shaped
  • B29B13/06—Conditioning or physical treatment of the material to be shaped by drying
  • B29B13/065—Conditioning or physical treatment of the material to be shaped by drying of powder or pellets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B9/00—Making granules
  • B29B9/16—Auxiliary treatment of granules

Definitions

• the present invention has for object a plant for a dehumidification process of granules, particularly of plastic material, to be subsequently used in the molding processes.
• the invention finds particular even if not exclusive application in the sector of the plastic materials working. Background Art
• the plastic material molding lines are known. They, upstream of the molding plant, must provide some quality control systems of the raw material for guaranteeing the production cycle and quality.
• Said control systems have the purpose of detecting the presence of residual humidity, present in the used material, allowing a specifical plant, in the specific case a dehumidifier, to intervene constantly or in time on the raw material, in order to feed the molding plant only with dried product, therefore optimised, maintaining a high working quality.
• the dehumidifiers are known to many.
• a ventilation system inside of the hopper is provided, allowing on one side the inlet of an air flow, preferably constant and dry, on the other one the outlet of air enriched with variable humidity percentages.
• Such forced circulation has the purpose of progressively reducing the humidity percentage detectable inside of the hopper, without interrupting the working cycle, allowing in the meantime, the regeneration of the means suitable to the dehumidification of the air inlet inside of the hopper.
• Said two lines in a traditional solution are essentially identical, and are made up of, besides the relative connections and electro-valves, a regenerating-dehumidification tower each comprising some molecular sieves, and a relative turbine.
• the turbine essential function is that of inletting the air taken from the hopper rich of humidity, inside of the respective tower, for then being dehumidified and newly inlet inside of the hopper in a continuous cycle.
• a high humidity rate detected inside of the working tower, of the two molecular sieves provisions, is reached, the plant suspends the relative circulation, activating at the same time the parallel line, in which the regeneration cycle had previously been carried out.
• Such cycles alternation now in one and then in the other tower, is necessary for allowing, in the tower concerned by the air flow circulation suspension, the evaporation of the water kept inside of the molecular sieve, being of the type provided with a suitable heat exchanger.
• the dehumidification plant described inevitably presents some problems, at first the manufacturing costs, which are particularly high, thus having negative consequences on the reference market, with sales reduction.
• the high costs are mostly caused by the need for double components, mainly the need for the double turbine.
• Such duplicity makes the plant, comprised the logic unit which manages its operation, particularly complex, making the ensemble particularly bulky, and at the same time rather anti-economical, because it is necessary to feed through the mains both the turbines, each of which has a high consumption/for hour.
• a second version, of the simplified type was recently proposed.
• the plant is endowed with a single turbine.
• the purpose of the single turbine is that of allowing the circulation of the air flow to be inlet into the process hopper, suitably divided between the working tower, which dehumidifies, and the regeneration tower.
• Figure 1. shows a scheme of the plant.
• Figure 2. shows a scheme of the plant as in Figure 1, in working conditions, providing a tower in process, and a second one in the regeneration phase.
• Figure 3. shows a scheme of the plant always of Figure 1., in working conditions, providing a cycle alternative to the one shown in Figure 2.
• Figure 4. shows a scheme of the plant as in Figure 1., in working conditions, providing both the towers in process.
• a plant (A) particularly for the dehumidification of plastic material granules, inserted into a hopper ( 1), is provided upstream of a complex plant for the plastic material working, particularly for the molding.
• said dehumidifier plant (A) comprises two working parallel lines, which may operate one independently from the other, or alternatively simultaneously. This is possible by providing essentially two towers (2, 3) each of which, internally, comprises at least a molecular sieve and at least an heat exchanger.
• the main purpose of said two towers (2, 3) is that of filtering the air, in a cycle of forced inlet, before this latter is let into the process hopper (1) and with the only purpose of ventilating the product in it contained. Afterwards, the amount of air enriched with humidity, may be discharged by the process hopper ( 1) for being filtered again and so on.
• a blowing turbine is provided (4), of the type having an independent lateral double channel. The purpose of said turbine (4), is that of constantly inletting some air through one or both towers (2, 3), so that the air flow, deprived of a good part of humidity, may, through some relative downstream ducts (2', 3'), be inlet into the process hopper.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Drying Of Solid Materials (AREA)
• Drying Of Gases (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11420184

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (5)

• 1997
  • 1997-06-03 IT IT97TV000072A patent/IT1293365B1/it active IP Right Grant
• 1998
  • 1998-06-01 WO PCT/IT1998/000145 patent/WO1998055284A1/en active Application Filing

Patent Citations (5)

Non-Patent Citations (2)

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