Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
2000-01-07
2001-05-15
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
C248S678000
Reexamination Certificate
active
06230481
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a base frame for a gas turbine and optional driven machinery such as generators and the like, which base frame includes a centrally arranged hollow section which acts as a torsion-absorbing body, sections or wings which extend from the hollow section and form an angle of approximately 90° with the longitudinal axis of the hollow section, one or more plate-shaped bodies arranged to cover wholly or partly the hollow section and the sections, where between the plate-shaped bodies, the sections and the hollow section there is formed at least one chamber on each side of the longitudinal axis of the hollow section.
DESCRIPTION OF THE RELATED ART
Gas turbines and optional driven machinery such as, e.g., generators, are often mounted together on base frames. This is especially true in the case of gas turbine installations on offshore oil platforms, where the gas turbine and the driven machinery can be mounted and dismounted as a unit. Around the gas turbine and the driven machinery there is usually provided an encasing housing having ventilation means or the like to maintain the temperature inside the housing within a desired range.
In such installations the torque between the gas turbine and the driven machinery is absorbed by the frame. This requires a robust frame structure and a frame of this kind is usually constructed in a different manner than a frame where the gas turbine and the driven machinery are arranged on separate frames, in such manner that the frame is not to absorb the torque.
In base frames which are to absorb torque, the frame is usually based on a round central tube which is to take up the torque or torsional forces.
A frame structure is known from inter alia EP 0 065 413, where a skid for rotating machinery is taught, consisting primarily of a torque-absorbing body in the form a round central tube, a so-called torsion tube.
U.S. Pat. No. 4,572,474 teaches a method of mounting a rotating machine and driven machinery on a base frame. However, this frame does not have a centrally positioned torque-absorbing body.
A disadvantage of a round central tube of this kind is that it involves the base frame having a relatively high constructional height, and also a relatively high weight, as a consequence of the necessary dimension to take up a desired torque.
All the equipment for controlling the operation of the gas turbine, the lubricating oil systems and feed devices for the gas turbine fuel are usually positioned on the top of the base frame, inside the housing. This positioning of the control and feed devices is disadvantageous from several points of view.
The fuel gas system is usually placed in an area in proximity to the high pressure turbine. If a blade becomes detached from the turbine, the blade will be thrown off and will penetrate the turbine housing and may also damage fuel gas valves and pipes. This may result in an explosion and fire.
A result of positioning the fuel gas system inside the housing is that the components are exposed to radiant heat from the turbine. This makes heavy demands on the temperature resistance of the components, which makes the fuel gas system more expensive.
In the event of an emergency shutdown of the turbine in a possible fire situation, the air dampers are usually closed preventing ventilation air from entering the housing, and the temperature inside the housing may thus increase to a level where cables and components are destroyed and where lubricating oil and hydraulic oil may convert to coke in the pipes.
In connection with fire classification of a turbine package, there are requirements with respect to the maximum number of mechanical pipe connections and joints. These requirements may be difficult to meet, because the pipe connections and joints must be welded, and this is also disadvantageous from a maintenance point of view.
Another major drawback with the conventional position of the fuel gas and lubricating oil systems is that there is no access for inspection when the turbine is in operation.
SUMMARY OF THE INVENTION
The object of the present invention is primarily to solve the aforementioned problems.
Another object of the invention is to move the fuel gas system away from the area where it may be exposed to damage as a result of detached turbine blades striking parts of the fuel gas system. The risk of explosion and fire is thus also reduced.
Another object of the present invention is to eliminate the temperature problems which may arise as a result of radiant heat from the turbine under normal operations and especially the temperature problems which may occur as a result of an emergency shutdown of the turbine.
This is achieved with a base frame for a gas turbine and optional driven machinery such as generators and the like, which base frame includes a centrally arranged hollow section which acts as a torsion-absorbing body, sections or wings which extend from the hollow section and form an angle of approximately 90° with the longitudinal axis of the hollow section, one or more plate-shaped bodies arranged to cover wholly or partly the hollow section and the sections, where between the plate-shaped bodies, the sections and the hollow section there is formed at least one chamber on each side of the longitudinal axis of the hollow section, characterised in that in said chambers there are provided pull-out modules which can house operating and control systems for the gas turbine, and that the hollow section is in the form of a hollow section having a rectangular, preferably square cross-section.
The chambers are preferably provided with rails and the modules are provided with wheels or similar sliding or rolling devices which interact with the rails.
The chambers are preferably mechanically ventilated to a minimum of 90 air changes per hour.
The operating and control systems which are arranged in the modules are preferably connected to the gas turbine by means of quick release couplings.
The gas turbine and the driven machinery are located on the same base frame, or they may be located on separate base frames.
The hollow section preferably extends throughout the entire length of the base frame.
REFERENCES:
patent: 4174482 (1979-11-01), Bollman
patent: 4317556 (1982-03-01), Dietrich
patent: 4501973 (1985-02-01), Fenemore et al.
patent: 4694190 (1987-09-01), Lane et al.
patent: 5626468 (1997-05-01), Muir et al.
patent: 0 065 413 (1982-11-01), None
Casaregola Louis J.
Kvaerner Energy A.S.
Young & Thompson
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