# US 4,395,217 A · Adaptor for extruding a plurality of streams of synthetic thermoplastic foam simultaneously from a single extruder

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- Number: US 4,395,217 A
- Document ID: US4395217A
- Status: Granted
- Kind: A
- Application number: 06/329,472
- Filed: 1981-12-10
- Granted: 1983-07-26
- Earliest claimed: 1980-12-19
- Assignees: Lavorazione Materie Plastiche L.M.P. S.p.A.
- Inventors: Alberto Benadi'
- Web page: https://patentgrep.com/patent/US4395217A

## CPC

- B29C 44/50: using pressure difference, e.g. by extrusion or by spraying {(B29C44/468 takes precedence)}
- B29C 48/695: Flow dividers, e.g. breaker plates
- B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- 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 (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

The adaptor, which can be applied to the delivery end of the extruder barrel, comprises a plurality of ducts for feeding corresponding extrusion heads, radiating from a common manifold chamber and each provided with a butterfly valve for the mutual adjustment of the flows of thermoplastic material in the respective ducts. Preferably the ducts with their respective valves are identical to each other and the valves are adjusted to give extruded products which are identical to each other.

## Claims

### Claim 1

A synthetic thermoplastic foam extruder comprising a barrel, injection means for injecting a foaming agent into said barrel and an adapter for extruding a plurality of streams of thermoplastic synthetic foam simultaneously from said extruder, comprising: a body having at one end means for attaching said body to said barrel of said extruder in axial alignment therewith; a manifold chamber formed frontally in said one end to receive the thermoplastic mass from said barrel; a plurality of ducts formed in said body, radiating from said manifold chamber and opening on the opposite of said body, each of said ducts terminating with attachment means for a respective extrusion head; a butterfly valve in each of said ducts and means for locking each of the valves individually in a desired angular position, each butterfly valve being comprised of a disc member having a median transverse section in the form of a rhomboid with the two opposing obtuse angles rounded off and with the two opposing acute angles being not greater than 60.degree. and having a dimension measured along the axis of rotation which is 60-80 percent of the corresponding dimension of the duct whereby in the position of maximum closure said butterfly valve cuts off at least 70 percent but not more than 90 percent of the flow cross section of the respective duct.

### Claim 2 (depends on 1)

A synthetic thermoplastic foam extruder as set forth in claim 1 wherein said ducts are identical to each other and in which said butterfly valves are identical to each other and disposed in the respective ducts in identical positions adjacent the attachment means for the respective extrusion heads.

### Claim 3 (depends on 2)

A synthetic thermoplastic foam extruder as set forth in claim 2 wherein said ducts are diverge from each other and are situated in radial planes uniformly angularly spaced from each other about the axis of the body of the adapter.