| 摘要 |
<p>Cellular and non-cellular polyurethane-forming ingredients of differing viscosity are metered to flow along separate passages into a mixer in an apparatus which is characterized in that a passage along which flows an ingredient of comparatively low viscosity is fitted with expansible means for receiving any surge of the said ingredient whereby to assist in maintaining flow of ingredients into the mixer in a constant metered proportion. The surge receiving means may be associated with means for returning received ingredient into the passage whereby to assist in compensating for any surge of ingredient along another passage. The surge-receiving means may comprise a flexible container subjected to a load, e.g. bellows, or a container, one wall of which may comprise a rolling diaphragm. The load on the flexible container may be imposed by a spring and/or pneumatic device. A blowing agent, e.g. fluorocarbon may be incorporated in one of the streams. Specifications 856,191 and 913,611 are referred to.</p> |
