Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/72—Heating or cooling
  • B29C45/74—Heating or cooling of the injection unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
  • B29C48/832—Heating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
  • B29C48/834—Cooling
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/40—Heating elements having the shape of rods or tubes
  • H05B3/54—Heating elements having the shape of rods or tubes flexible
  • H05B3/58—Heating hoses; Heating collars
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion

Definitions

• Conventional heating units used, for example, in plastics injection and extrusion processes are conven ⁇ tionally formed by casting a suitably shaped block about a heat sealing element.
• the casting process puts constraints upon the shapes which can be created for the block and the heat transfer properties of the unit are somewhat restricted by the embedding of the heat element within the block.
• this invention provides a heating unit comprising an extruded metal alloy block whose one face is formed with grooves in which are securely mounted heat transfer pipes whose inner faces bear against the wall surfaces of the grooves and whose outer faces are aligned with the said one face of the block.
• grooves of the heating transfer pipes will be of square, rectangular or half-round cross-section.
• the edges of the grooves may be peened over to retain the heat transfer pipes.
• Another possibility would be to form the heat transfer pipes and the grooves in dovetail form so that the heat transfer pipes would be slid into place.
• the heat transfer pipes may incorporate heating elements or could provide fluid passageways for heating or cooling liquids.
• the extruded blocks can be suitably shaped so that said one face forms a circular or part-circular internal surface. In the latter case several parts can be secured together to define a complete circle of a desired size.
• the extruded block can have dovetailed sections along edge walls enabling a number of such blocks to be linked together.
• a preferred material for the block is aluminium.
• the face of the block opposite to said one face may have fins formed thereon which could act, for example, as cooling fins.
• Figure 3 is an enlarged detail of part of Figure 1;
• Figure 4 is a longitudinal section through part of the heating unit of Figures l and 2;
• FIG 5 is a section through an enlarged detail of part of an alternative mounting arrangement for heating elements of the heating unit.
• the heating unit shown in Figures 1 to 4 of the drawings defines a cylindrical passageway 1 which can receive a tube 2 forming part of plastics injection or extrusion equipment.
• the main part of the heating unit is 5 defined by a ring-shaped block 3 formed from aluminium. This is formed by an extrusion process so as to define fins 4, the block being shaped subsequently to create the ring shape. In this instance two semi-circular parts are created which are held together by fixing bolts 5.
• the ring 3 also incorporates square cross-section grooves 6 within which are fitted correspondingly shaped heating elements 7 whose ends 8 are brought out through the body of the block 3, as shown in Figures 1 and 3. As can be seen from Figures 2 and 3, three ring-shaped blocks 3 are
• the rings 3 are surrounded by an outer casing 10 provided with inlet and outlet passageways 11 and 12 through which air can be blown
• heating unit illustrated in the drawings has a number of advantages over the conventional cast unit where the heating element is embedded in the block.
• the aluminium block can be formed by the extrusion process
• the main advantage is the positioning of the heating element 7 directly on the inner face 1 of the equipment so that the heating is applied directly to the tube 2 rather than having to pass the heat through part of the block 3.
• the flat inner face of each heating element 7 permits the good heat transfer and there is also substantial surface contact between the heating element 7 and the body of the block 3 so that heat is rapidly transmitted through the block 3.
• An additional advantage is that the heating elements 7 are readily accessible and can therefore be replaced as required.
• the corners of the opening 6 of the block 3 will be peened over to hold the heating elements 7 in place.
• the heating elements could have other forms of cross-sectional shape so as to fit into suitably defined grooves 6 in the block 3, with the exposed face of each heating element 7 lying flush with the inner face 1 of the block 3.
• a heating element of semi-circular form could be used.
• Another possibility is to form the heating element of a dovetail shape which could then be slid into a complementary groove 6.
• Dovetail sections could be formed, as at 13 and 14

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10668475

Family Applications (1)

Country Status (3)

Families Citing this family (3)

Family Cites Families (8)

• 1989
  • 1989-12-22 GB GB898929145A patent/GB8929145D0/en active Pending
• 1990
  • 1990-12-18 WO PCT/GB1990/001976 patent/WO1991009720A1/en not_active Ceased
  • 1990-12-18 EP EP91900876A patent/EP0508998A1/de not_active Withdrawn

Non-Patent Citations (1)

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