# US 4,393,658 A · Extraction condensing turbine

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- Number: US 4,393,658 A
- Document ID: US4393658A
- Status: Granted
- Kind: A
- Application number: 06/281,934
- Filed: 1981-07-10
- Granted: 1983-07-19
- Earliest claimed: 1978-10-13
- Assignees: Blohm & Voss AG
- Inventors: Wulf Bohnenkamp; Gerd Hempel
- Web page: https://patentgrep.com/patent/US4393658A

## CPC

- F01D 25/12: Cooling
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)

## Abstract

A steam extraction turbine including a steam extraction section from which steam may be extracted from the turbine for external use prior to the low pressure section of the turbine. In order to avoid overheating of the low pressure section when the amount of extracted steam is high, there is provided a cooling steam stage immediately upstream of the low pressure section through which steam is applied to the low pressure section to prevent overheating. The cooling steam stage includes blades of the rotor and thus permits energy to be extracted from the steam applied to prevent overheating of the low pressure section, the extracted energy being used to drive the turbine thereby increasing turbine efficiency.

## Claims

### Claim 1

A steam extraction turbine comprising: a high pressure turbine section; a low pressure turbine section from which steam is exhausted from said turbine; a steam extraction section arranged in the steam flow path intermediate said high and said low pressure sections of said turbine from which steam is fed into said low pressure section; said steam extraction section including steam extraction chamber means fed from said high pressure section from which steam is extracted from said turbine for external use; valve means between said steam extraction chamber means and said low pressure section for controlling the amount of steam flowing therebetween; and cooling means defining a steam flow path between said steam extraction chamber means and said low pressure section in parallel with the flow path through said valve means for supplying steam to prevent overheating of said low pressure section, said cooling means including energy extraction means for extracting from the steam flowing through said cooling means energy which is applied to drive said turbine.

### Claim 2 (depends on 1)

A turbine according to claim 1 including stator means and rotor means wherein said energy extracting means comprise rotor blades of said rotor means.

### Claim 3 (depends on 2)

A turbine according to claim 2 wherein said cooling means include nozzle means located in the steam flow path defined by said cooling means upstream of said rotor blades of said energy extracting means.

### Claim 4 (depends on 2)

A turbine according to claim 2 including stuffing box means between said stator means and said rotor means sealing said steam extraction chamber means from said low pressure section.

### Claim 5 (depends on 1)

A turbine according to claim 1 wherein said cooling means is arranged to maintain sufficient steam flow to said low pressure section to prevent overheating thereof when the quantity of steam flowing through said valve means is insufficient to prevent such overheating.

### Claim 6 (depends on 1)

A turbine according to claim 1 wherein said low pressure section is utilized primarily for peak load conditions of said turbine and wherein said cooling means operates to minimize the amount of energy which is dissipated in preventing overheating of said low pressure section when use of said low pressure section is not required for driving said turbine.