Mixing head for mixing two or more plastics components which react to form foam, in particular polyurethane

US4702890A · kind A · utility

Assignee

• Elastogran Maschinenbau GmbH · DE

Inventor

• Josef Wallner · Holzkirchen, DE

Key dates

• Filing date: Dec 18, 1985
• Grant date: Oct 27, 1987
• Expiry date: Dec 18, 2005

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29C44/581
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

The mixing head is provided with a flow restrictor 5 which can be driven into the mixing chamber 2 downstream of the inlet orifices 3, and whose front face (for 6) is matched to the contour of the mixing chamber to avoid leaving any space here which cannot be purged by the purging plunger. When the flow restrictor is pushed forward into its working or restricting position, it is simultaneously rotated, the extent of rotation being no more than 90.degree. by the time the restricting position has been reached. This makes it possible to drive the flow restrictor much further into the mixing chamber than when no rotation is effected. The tongues or projections 6 produced as a result of matching the front face to the contour of the mixing chamber only come into contact with the sections of the mixing chamber wall which are opposite the flow restrictor. The flow restrictor can be pushed in an appropriate distance, making it possible to achieve a good restricting effect and therefore to exert a corresponding great influence on the mixing procedure or on the discharge characteristics.