Patent GB-1231668-A (GB)
IPC: F02C3/36
Filed: 1968-12-16
Abstract: 1,231,668. Rotary compressors; gas turbine plant; turbines. DAIMLER-BENZ A.G. Dec.16, 1968 [Dec.30, 1967], No.59678/68. Headings F1C, F1G and F1T. [Also in Division F2] A gas turbine plant having low- and high-pressure compressors driven by a turbine or turbines operated by combustion gases from a combustion chamber fed by the compressors, and a useful power machine also operated by the combustion gases, has means for alternately connecting the compressors in series or parallel flow. In one embodiment, Fig.1, a three shaft gas turbine plant comprises low and high-pressure compressors V n , V h , respectively, which supply air or combustible mixture through a pre-heater W to a combustion chamber B. The combustion gases leaving the latter operate high- and low-pressure turbines T h , T n , driving the compressors through concentric shafts A n , A n , and a useful power turbine AT which can be connected to the turbine T n  by a clutch or freewheel œ. The exhaust from the turbines gives up heat in the pre-heater W. In the condition shown the working fluid-flow, as indicated by the heavy line, is in series throughout the plant. However by operating a changeover valve S 1  pipe c can be shut off and pipe b 1  opened so that the flow from the L.P. compressor Vn passes directly to the pre-heater W, the compressors V n , V h  thus operating in parallel, Fig.2 2 (not shown). Likewise, by operating changeover valves S 2  and S 3  to open pipes f 1  and i 1  while closing pipe k the power turbine AT can be connected in parallel with the compressor driving turbines T h , T n . The changeover from series to parallel operation and vice versa may be made manually, or automatically in response to operating conditions such as torque, temperature, rotational speed or compressor pressure ratio. The plant may drive a road vehicle and be arranged so that during low load running all units are in series, whilst at higher loads, or during braking, the units operate in parallel. During acceleration, the compressors may be in series but the power turbine AT in parallel with the compressor driving turbines. The L.P. compressor V n  may be of axial flow type and the H.P. compressor V h  radial flow. The compressors and turbines may have adjustable blades. In a modification, Figs.3, 4 (not shown), the plant is of two shaft type having a single turbine T driving the L.P. and H.P. compressors V n , V h  through a shaft (A). In a further modification, Fig. 5, a three shaft plant has L . P . and H.P. axial flow compressors V n , V h  driven by turbines T n , T h  disposed radially outwards of and integral with the respective compressor rotors. Between the L.P. and H.P. units is disposed a changeover valve S 1  and between the L P. unit and the useful power turbine AT is disposed a changeover valve S 23 , corresponding to the valves S 2  and S 3  of the Fig .1 embodiment. The plant can operate in series and/or parallel by operation of the valves S 1 , S 23  and is shown in the parallel operating condition. The valve S 1  comprises a body of revolution which can be rotated through an angle of, say, 45 degrees. The valve body contains curved axial-radial passages Y 1 , Y 2 , Figs.5, 6, alternating with axial passage X. In the position shown, passages X are obstructed by fixed members so that air leaving the L.P. compressor V n  through channel b is diverted radially outwards through passages Y 2  and pipe b 1  to the pre-heater W, while air from atmosphere flows radially inwards through passages Y 1  and channel C 1  to the H.P. compressor Vh. For series operation of the compressors, valve S 1  is rotated to the Fig.8 position (not shown) in which passages Y 1 , Y 2  are closed-off by the fixed members and passages X are open so that air leaving the compressor V n  flows through passages X to the compressor V h . The body valve S 1  has axial passages Z radially outwards of passages X, the passages Z being open regardless of the angular position of the valve body so that compressor driving turbines T h , T n  are always in series. The valve S 23  between turbine T n  and the power turbine AT operates in a generally similar way to valve S 1  to place the turbines AT, T n  in series or parallel. Fig.12 (not shown), illustrates valves S 1 , S 23  in a two shaft gas turbine plant. The valves may have passages for cooling air. The turbines may also be cooled by an arrangement which comes into operation automatically with the changeover to parallel working. Figs.16, 17 (not shown) illustrate the disposition of the combustion chamber B above the turbines and compressors of the plant, with the pre-heat W arranged in two parts (W 1 , W 2 ) at opposite sides of the combustion chamber. Air filters (F, F 1 ) are disposed at the compressor inlets.