On-off burner control by cycle time variation

US4938684A · kind A · utility

Assignee

• LVE Verfahrenselektronik GmbH · DE

Inventors

• Nolte Karl · Essen, DE
• Detlef Maiwald · Moers, DE
• Michael Bock · Pittsburgh, US
• Thomas Spahr · Hungen, DE

Key dates

• Filing date: Aug 30, 1989
• Grant date: Jul 3, 1990
• Expiry date: Aug 30, 2009

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F23N2237/02
• WIPO field: Thermal processes and apparatus
• WIPO sector: Mechanical engineering

Abstract

The burners of a fuel-fired system are controlled by means of a feedback control system for temperature control. The control system comprises temperature measuring means, a controller for temperature control, final burner controlling means translating the output from the controller into an appropriate burner input rate, and a digital central processing unit determining pulse spacing (t.sub.ps), pulse duration (tON) and pulse separation (tOFF). A minimum pulse spacing (.sup.t ps.sub.min), being the sum of the minimum pulse duration (tON.sub.min) and the minimum pulse separation (tOFF.sub.min), is present and used as an input rate reference value. Using the input rate reference value for the minimum pulse spacing, the burner input rate is controlled in accordance with process requirements by varying pulse spacing (t.sub.ps) through varying pulse separation or pulse duration. For input rates lower than the input rate reference value, pulse separation is increased, and for input rates higher than the input rate reference value, pulse duration is increased with pulse separation remaining the minimum pulse separation. The feedback control system substantially improves the rangeability of…