Rotary kinetic fluid motors or pumps – With control means responsive to non-cyclic condition... – Responsive to moving member developed fluid force – current...
Patent
1993-12-20
1995-11-07
Look, Edward K.
Rotary kinetic fluid motors or pumps
With control means responsive to non-cyclic condition...
Responsive to moving member developed fluid force, current...
415 20, 60662, F01D 2100
Patent
active
054643180
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a control system for control of steam flows when injecting and extracting steam in connection with steam turbines, especially when using steam turbines in industrial processes where the steam consumption of the turbine varies.
BACKGROUND OF THE INVENTION
In certain applications industrial steam turbines are connected to a process network with greatly varying steam consumption. An optimal utilization of the turbine then receives that at certain times steam is to be injected into the turbine from the process network, whereas on other occasions steam is to be extracted from the turbine to the process network.
In order to inject and extract steam at an optimal location in the turbine, multi-point injection/multi-point extraction in accordance with known methods for injection/extraction of steam within the turbine technique are utilized. In the case of injection, the optimal point is as high up in the turbine as possible, that is, it takes place at a point in the turbine with high steam pressure. Optimal extraction is carried out in a corresponding manner as far down in the turbine as possible, that is, at a point with low pressure in the turbine.
According to the conventional technique for externally controlled extraction or injection, separate valves are currently used for controlling the steam flows for injecting steam into the turbine, that is, a number of valves equal to the number of injection points are controlled to open and close to control any steam flows to the different injection points. In a corresponding way, any steam flows from the turbine through extraction points in the turbine are controlled by means of separate valves in connection with extraction of steam from the turbine. The number of extraction valves is then equal to the number of steam extraction points from the turbine.
Consequently, with the current technique for controlling injection and extraction of steam into and from a steam turbine, it is necessary to provide a number of valves equal to the sum of the number of injection and extraction points in the turbine. This entails a large cost for the valves and an unnecessarily complicated valve control as well as, in certain cases, disadvantages from the performance point view of.
SUMMARY OF THE INVENTION
The present invention relates to a control system for control of injection and extraction of steam in a steam turbine in which, the same valves being used both for injection of steam into the turbine and extraction of steam from the turbine. The valves which are common for injection and extraction are controlled to be timely opened and closed in dependence on pressure conditions at injection points and extraction points, respectively, in the turbine and on the pressure prevailing in the process network connected to the valves such that injected or extracted steam is utilized in an optimal manner.
The conduits for extraction of steam are the same as the conduits for injection of steam.
In the following description, a valve is designated and considered a lower valve if it communicates with and controls the steam from and to an extraction/injection point, respectively, which is located at a connection point of the turbine at a lower pressure level in relation to the other extraction/injection points. Correspondingly, a valve is designated a higher valve if it communicates with and controls the steam flow from an extraction/injection point which is located at a connection point of the turbine at a higher pressure level in relation to the other extraction/injection points.
The present invention operates according to the principle that valves during, for example, extraction of steam are opened in,a certain sequence. Primarily, a lowest valve is opened which extracts steam from that of the two extraction conduits which is in communication with the extraction point with the lowest steam pressure in the turbine, referred to here as the lowest extraction point. If, at some time, the pressure at the lowest extraction point does not maintain
REFERENCES:
patent: 3342195 (1967-09-01), Wagner
patent: 3487993 (1970-01-01), Rannenberg
patent: 4118935 (1978-10-01), Andersson
patent: 4156578 (1979-06-01), Agar et al.
patent: 4309873 (1982-01-01), Koran et al.
patent: 4448026 (1984-05-01), Binstock et al.
patent: 5242263 (1993-09-01), Mondoloni
Derwent's Abstract No. H79 E/26, SU 861 666.
Eklund Sivert
Jonsson Claes
Sjoberg Lars-Goran
ABB Stal AB
Look Edward K.
Sgantzos Mark
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