Method for feed water control in waste heat steam generators
US5771846A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1996 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | Mar 22, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF22B35/007
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
In a method for feed water control in waste heat steam generators, in particular drum boilers with a circulating pump (9) and drum boilers with natural circulation employed in combination power plants, wherein, by a three-component control by means of a superordinated level regulator (13) and a flow-through regulator (14) subordinated to the level regulator (13), the set value (S.sub.in) of the flow-through regulator (14) is displaced by the level regulator (13) in such a way that the level in the drum (6) is always regulated to the set value (S), regardless of interfering effects, the flow-through regulator (14) for the feed water flow (m.sub.s) is guided by the heat amount (Q.sub.AG) in the exhaust gas flow. The output signal of the flow-through regulator (14) for the feed water flow (m.sub.s) is limited, wherein as the function of the heat amount (Q.sub.AG) in the exhaust gas flow a selection is made between a limit value (m.sub.1) for the start-up operation and a limit value (m.sub.2) for normal control operation and the switch from (m.sub.1) to (m.sub.2) takes place via a time function element (16) with an idle time (T).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.