Pump for secondary circulation

US5143049A · kind A · utility

Inventors

• Karsten Laing · Althütte, DE
• Nikolaus Laing · Spaichingen, DE

Key dates

• Filing date: Mar 26, 1990
• Grant date: Sep 1, 1992
• Expiry date: Mar 26, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/85954
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

In a plumbing installation wherein hot water is piped from a water heater or reservoir to a plurality of taps by a distribution conduit, an improved recirculation circuit of limited power consumption to continually pump small amounts of hot water from said conduit back into said reservoir which comprises a low power radial pump unprotected by a check valve against backflow, but having a rotary impeller with linear radial vanes leading to an annular output channel larger than necessary for maximum pumping throughput. The oversized annular channel and linear vanes limit the impact of any backflow upon the impeller and prevents its operating as a tubine as the pump is subjected to back pressure when a large amount of water is being drawn through the taps.