US1767714A - Steam power plant for high pressure - Google Patents

Description

June 24, 1930.

w. STENDER 1,767,714 STEAM POWER PLANT FOR HIGH PRESSURE Filed May 12, 1925 Patented June 24, 1930 r UNITEDv STATES PATENT OFFICE WALDEMKB STENDER, 0F BERLIN-CHARLOTTENBURG, GERMANY, ASSIGNOR TO SIEHENS-SCHUCKERTWERKE, GESELLSCHAFT MIT BESCHRANKTER HAFTUNG, OF BIEMENSSTADT, NEAR BERLIN, GERMANY, A. CORPORATION OF GERMANY STEAM IPOWER PLANT FOR HIGH PRESSURE Application filed Kay 12, 1925, Serial 1T0. 29,748, and in Germany May 13, 1924.

My invention relates to improvements in steam power plants for high pressure and in which the steam is generated at very high pressures and temperatures, for instance above the Critical pressure and above the critical temperature and is then reduced to the ressure suitable for general use.

T e diagram of such a plant is shown in the drawing aflixed to my specification and forming part thereof.

Referrmg to this drawing 1 is a feed pump which forces the water through the steam generator 2 at a pressure for instance above the critical pressure. This generator 2 consists of a system of tubes which is heated by a furnace 10 to such an extent that the temperature exceeds the critical temperature. In this manner the water is directly converted into steam. By means of a throttle valve3 the steam pressure was usually heretofore reduced alread to the pressure suitable for general use fore it entered the superheater 4. This superheater serves in such a case only the urpose of superheating and of preventing t e condensation of the steam owing to the reduction of the pressure. The steam now enters the live steam pipe 5, passes throu h the steam power engine (turbine) 6, which may drive an electric generator 7, and then enters a condenser 8 from which the condensate is withdrawn again by the pump 1. The operating medium thus describes a complete cycle.

It has also been suggested in the prior art to construct the superheater in tubular form and of such dimensions, that the generated steam is throttled in the tubular superheater from the generated pressure directly down to working pressure b virtue of the friction encountered in the tu s. This latter method of throttling utilizes the well-known recognition, that the transfer of heat from a medium, flowing through a tube, to the wall of said tube, or vice verse, is a function of the speed of flow and increases substantially linearly with it, while the resistance to the flow increases substantiall with the square of the velocit of the me ium. Both .prior art methods ave disadvantages. The first steam generator.

consumption conditions exist, which does not happen under practical operating conditions. This is particularly the case with generators of small capacity and when the steam is generated at high pressures. If in such a plant the output is reduced, the steam flow through the superheater is correspondingly reduced, and owin to the square flow law above-mentioned, t e tube resistance is reduced to a still larger degree, thereby causing undesirable pressure conditions in the Similar results exist in such a plant if at full output the steam conditions (temperature and thus specific steam volume) should vary due to improper heat supply.

According to my invention the superheater is so proportioned that when it carries maximumload the available drop of pressure is approximately consumed by theflow resistance. The limit values between which the pressure reduction occurs are the pressure at the oint of steam generation and the pressure 1n the live steam pipe.

Consequently at full load the entire pres- I at varying output conditions and thus maintains, also for the reason above stated, the heat/transfer at all operating conditions at a high level. The material of the superheater 4 is in a thus dimensioned superheater utilized to the highest extent possible in practice.

by the superheater for the rea-' The invention may be employed in all perheated at simu taneous reduction of pressure. The a plication of my invention is of course not limited to steam plants but may equally well be employed when liquid media other than water are used.

What I claim as my-invention is 1- 1. A steam generating plant having means for enerating steam at high temperatures and igh pressure conditions and in which the generated steam is consumed at a working pressure substantially below the generating pressure, and including in combination, a superheater for superheating the steam, said superheater being of the tubular type and having tubes of such small cross-section that the entire pressure reduction to the lower working pressure when the plant is operated under high load conditions is effected by the gradual throttling action of the tubes themselves which throttling action occurs simultaneously with the superheating of the steam passing through the tubes, and a supplemental throttle for efi'ecting supplemental pressure reduction of the enerated steam when the plant operates un er lower load conditions and when the velocity of the steam through the tubes of small cross-section is reduced to such a degree that the desired pressure reduction cannot be efiected by the sole throttling action of the tubes themselves.

2. A steam generating plant having means for generating steam at hi h pressure and temperature and in which t e steam is consumed at a working pressure which is substantially below the generating pressure and including in combination, a superheating means comprising tubes of such small cross section as to afiord gradual throttling of the steam to the lower worln'n pressure when the plant operates under ull load conditions, and to simultaneousl efl'ect super-v heating with the maximum e ciency of heat transfer to the steam when the plant operates under such full load conditions, and also including a supplemental throttle for efiectin a part of the pressure reduction when t e plant operates under relatively lower load conditions for the purpose of maintaining good heat transfer conditions in the superheater.

3. A steam generating plant'having means for generating steam at high temperatures and atsubstantiall critical pressure conditions andin whic the generated steam is consumed at substantially lower working pressure conditions and including in combieo nation, a superheating means of tubular type for superheating the steam after its generation, said tubes being of such. small dimen sion that the entire pressure reduction to the lower working ressure when the plant is operated under igh load conditions is effected by the gradual throttling action of I the tubes themselves, which throttling takes place simultaneously with the superheating of the steam passing through the tubes, an also including a supplemental throttle disposed between the generator and the consumer for cooperating with the tubes to effect further and additional throttling necessar when the plant is operated under lighter load conditions, said supplemental throttle also serving to maintain critical pressure conditions for steam generation which cannot be maintained by the throttling action of the tubes alone when the plant is so operated under relatively lower load conditions.

4. A steam generating plant, having a steam generator for generatin steam at high pressure which steam is tolie supplied at lower pressure to a steam consumer, and including in combination a tubular superheater so proportioned in tube size that when the generator operates at maximum output, the high pressure of the steam is gradually reduced to the desired working pressure durin the superheating process substantially y the resistance 0. ered by the superheater to the flow of the steam, and a throttle valve between the generator and the superheater for compensating for small pressure variations due to practically un avoidable inconsistent steam or load conditions, to which the superheater cannot respond.

In testimon whereof I aflix my si nature.

ALDEMAR STEN ER.

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