US 5,056,468 AGranted

Steam generator

AssigneeSiemens Aktiengesellschaft

InventorsEberhard Wittchow, Joachim Franke, Wolfgang Vollmer

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Abstract

A steam generator includes a gas flue having burners for fossil fuel, a gas-tight tube wall with tubes, inlet and outlet headers connected to the tubes, the outlet header being at a higher level than the inlet header, and a down pipe outside the tube wall connecting the outlet to the inlet header. A steam line is connected to the outlet header and at least one heating surface is connected downstream of the outlet header in the steam line. A feedwater line is connected to the gas flue and an economizer is connected upstream of the gas flue in the feedwater line. A regulating device for influencing feedwater flow in the feedwater line detects at least one of: the steam enthalpy in the heating surface or the steam line downstream of the heating surface, the steam temperature in the heating surface or the steam line downstream of the heating surface, the thermal output transfer to the tubes, a ratio of feedwater flow in the feedwater line to steam flow in the steam line, a ratio of injection water flow into an injection cooler connected in the steam line to feedwater flow in the feedwater line, and residual moisture of steam in the steam line.

Claims19

Dependent claims

A steam generator, comprising:

a gas flue having burners for fossil fuel, a gas-tight tube wall with tubes, an inlet header and an outlet header connected to said tubes, said outlet header being at a higher local level than said inlet header, and a down pipe outside said tube wall connecting said outlet header to said inlet header, so as to permit flowing of a fluid between said outlet header and said inlet header;
a steam line connected to said outlet header, at least one heating surface connected downstream of said outlet header in said steam line, so as to permit flowing of a fluid from said outlet header to said heating surface;
a feedwater line connected to said gas flue, an economizer connected upstream of said gas flue in said feedwater line, so as to permit flowing of a fluid from said economizer to said gas flue;
and a regulating device for influencing feedwater flow in said feedwater line, said regulating device detecting at least one of the following controlled variables:
(a) steam enthalpy in one of said heating surface and said steam line downstream of said heating surface,
(b) steam temperature in one of said heating surface and said steam line downstream of said heating surface,
(c) thermal output transfer to one of said tubes of said gas-tight tube wall,
(d) a ratio of feedwater flow in said feedwater line to steam flow in said steam line,
(e) a ratio of injection water flow into an injection cooler connected in the steam line to feedwater flow in said feedwater line, and
(f) residual moisture of steam in said steam line.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/648,904Filed 31 Jan 1991
Priority: EP 90101940.631 Jan 1990
Granted: 15 Oct 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

F22B 29/026
Without drums, i.e. without hot water storage in the boiler: operating at critical or supercritical pressure
F22B 35/02
Control systems for steam boilers: for steam boilers with natural convection circulation
F22B 35/086
Without drum, i.e. without hot water storage in the boiler: operating at critical or supercritical pressure
F22B 37/141
Supply mains, e.g. rising mains, down-comers, in connection with water tubes: involving vertically-disposed water tubes, e.g. walls built-up from…