US1947477A - Turbine-driven compressor apparatus - Google Patents

Description

Feb. 20, 1934. A LYSHQLM 1,947,477

TURBINE DRIVEN COMPRESSOR APPARATUS Filed Jan. 24, 1931 9 ATTORNEY names Feb. at, 1934 rerun QFFHCE TURBINE-DRIVEN COMPRESSOR APPARATUS Ali Lysholm, Stockholm, Sweden, assignor to Aktiebolaget Ljungstroms Angturbin, Stockholm, Sweden, a Swedish joint-stock company Application January 24, 1931, Serial No. 510,924, and in Germany January 27, 1930 8 Claims.

The present invention relates to turbine driven compressor apparatus and has particular reference to turbine driven compressor apparatus of the type in which compression of the medium to be compressed is effected in a plurality of stages so as to provide a compressed medium of relatively high pressure. Still more particularly the invention relates to turbine driven compressor apparatus in which the driving medium for the turbine consists of an elastic fluid which may be gas.

A general object of the invention is to provide new and improved apparatus of the character above set forth in which the arrangement of the compressor and turbine parts of the apparatus is such that the apparatus as a whole will, with a very simple structure, permit the different compressor parts to operate in the most eihcient manner not only under constant load conditions but also under conditions of varying load. Another object is to provide a new and improved turbine compressor unit in which the arrangement of compressor and turbine parts is such that the apparatus as a whole may be made lighter and more compact, for a given capacity, than the forms of turbine driven compressor apparatus heretofore employed.

The above general object and other and more detailed objects of the invention are attained by providing atleast two separate compressor parts adapted to compress the medium to be compressed through difierent pressure ranges,

connecting these parts in series with respect to the how of the medium to be compressed and connecting separate compressor parts separately to different shafts of a radial flow turbine of the double rotation type.

The more detailed nature of the invention and the advantages to be derived from its use, together with the specific manner in which the apparatus just described is enabled to effect the objects of the invention, may best be understood from the following description of a suitable form of apparatus for carrying the invention into effect, which is illustrated in the accompanying drawing forming a part of this specification.

Turning now to the drawing. which shows the apparatus in longitudinal central cross-section, the turbine part comprises a casing 10 having a base portion 11 adapted to provide a support for the apparatus. overhung from casing 10 and at opposite sides thereof are two compressor casings l and 2. Casings 1, 2 and .10 may be said to constitute the housing structure of the apparatus A shaft 3 is journalled at 44 in a suitable bearing carried by the turbine casing 10 and at its outer end is journalled in bearing 42 in the casing 1. A thrust bearing 43, which may be of the Michel type, is provided for taking up unbalanced thrust loads on shaft 3.

A second shaft 3a, in axial alignment withshaft 3, is journalled at 51 in a suitable bearing in the'turbinecasing 10 and at its outer end in a bearing 49 in the casing part 2. A thrust bearing similar to bearing 43 is provided to take up unbalanced thrust forces on shaft 3a.

Shafts 3 and 3a extend inwardly toward each other from the bearings 44 and 51 to provide turbine shaft parts 45 and 52 respectively, which shaft parts may be integral with shafts 3 and 3a 7 or separate and rigidly joined to the shafts by suitable connections at 46 and 53.

Rigidly mounted on the shaft part 45 is the turbine disc 47 and rigidly mounted on shaft part 52 is the turbine disc 48. Discs 4'! and 48 carry respectively a plurality of rings of turbine blades 56 and 57, these rings being interleaved to provide a radially extending path of flow for motive fluid from the central admission chamber 54 (to which motive fluid is admitted in known manner through inlet conduits not shown in the drawing) to the exhaust space 55.

For preventing leakage of motive fluid past the turbine discs 47 and 48 and also for exerting compensating thrust force on the turbine discs, the radially extending labyrinth packings 58 and 59, of known type, are provided between the turbine discs or rotors 47 and 48, respectively, and the adjacent stationary parts of the turbine.

The compressor portion of the apparatus comprises two fluid compressing members in the form of centrifugal rotors located in the casing parts 1 and 2. The casing part 1 and it's rotor form the low pressure part of the apparatus which comprises six serially connected stages. Each 9 stage has a row of rotor blades adapted to force the medium to be compressed radially outwardly through a row of diffusor blades to an intermediate receiver chamber from which the medium to be compressed is drawn radially inwardly through suitable guide blades to the'inlet of the row of rotor blades of the next succeeding stage. In the apparatus illustrated the. rows of rotor blades of the several stages of the low pressure compressor part are indicated at 15, 16, 17, 18, 19 and 20 and the rows of diffusor blades are indicated at'21, 22.23, 24, 25 and 26. The rows of guide blades for the several stages are indicated at 16a. In the intermediate chambers or receiver spaces indicated at 40 ther are preferably located cooling elements, indicated at 27, 28, 29, 30 and 31, for cooling the medium to be compressed between the several compression stages. The inlet forthe medium to be compressed is in- 5 dicated at 7 and outlets 8 are provided for delivering the medium as compressed in the low pressure compressor.

The high pressure compressor part comprises eight compressor stages in the casing part 2, the general arrangement of these stages being similar to the stages already described in connection with the low pressure compressor part. The inlets to the high pressure part are indicated at 7a and the outlet from the high pressure part is indicated at 8a.

Outlets '8'of the low pressure part and. inlets 7a of the high pressure part are connected by pipes 41.

From the drawing it will be evident that the low pressure compressor part comprises a rotor of larger mean diameter than the rotor of the high pressure compressor part. Also, the low pressure part comprises a fewer number of stages than the high pressure part. The rotor of the high pressure part, being smaller in diameter and lighter than the rotor of the low pressure part, is adapted to operate at higher speeds than the rotor of the low pressure compressor. These relative sizes of the rotors and the possibility of operating the high pressure rotor'at a higher speed than that of the low pressure rotor permit compression to be effected in the most advantageous manner with respect to the size and weight of equipment required for a given capacity and also permit compression to be effected with the highest possible compressor efiiciency. It will be evident that since the medium to be compressed increases in specific weight and decreases in volume as it passes through the successive pressure stages of the compressing apparatus, the rotors in the stages of higher pressure should be designed to compress smaller volumes than the rotors of the stages of lower pressure and, consequently, the rotors of the higher pressure stages may advantageously operate at higher speeds" than the rotors of the lower pressure stages. This is particularly advantageous in the case of compressors adapted to deliver the medium to be compressed at a final pressure which is relatively high, since the leakage losses, which tend to increase with increases in pressure, may be minimized because of the relatively smaller clearance spaces obtainable with compressor rotorsgof relatively small diameter. I

The advantage to be derived from utilizing a relatively large compressor rotor for the low pressure part and a relatively small'rotor operating at higher speed for the high pressure part may be illustrated by the following example:

Let it be assumed that the turbine in the apparatus shown in the drawing is of a 'type such that shafts 3 and 3a are both driven at the same speed. Let it further be assumed that the adia batic heat drop through the turbine is 100 calories. In order to properly utilize the power developed by this heat drop in the turbine at low pressure compressor part having six stages with a mean rotor diameter of 1.2 meters and a high pressure compressor part having eight stages with a mean rotor diameter of 1.03 meters will be required. If, now, the same heat drop is utilized in a double rotation turbine, which permits the compressor rotors to turn at different speeds,

and the high pressure compressor part is designed.

for a rotor speed 35% higher than the speed of the low pressure rotor (the low pressure part being designed fora rotor speed. the same as that of the two compressor rotors in the example above), it will be found that the compressor can be made with five stages in the low pressure part, having a mean rotor diameter of 1.2 meters, and that the high pressure part can be constructed with seven stages having-a mean rotor diameter of .88 meters.

Furthermore, calculations which need not be given here in detail show that with the latter arrangement ofv compressor parts operating at difierent speeds, an increase in eflioiency of the compressor as awhole of from 2 to 3% may be obtained, compared with the efficiency of the compressor having low and high pressure parts designed to operate at the same speed.

Thus, in accordance with the present invention, by driving two serially connected compressor parts independently from the independently movable shafts of a double rotation turbine, the size and number of stages employed to absorb a given amount of power may be'materially reduced as compared with thelcompressor structure necessary when all of the compressor rotors operate at the same speed, and at the same time the efiiciency of the compressor apparatus may be increased.

Also, by driving the two compressor parts from the separate shafts of the same turbine, and

regardless of whether or not the apparatus is designed to take advantage of the feature of having the two shafts operate at different speeds, automatic balance of the distribution of the load between the twocompressor parts is obtained without the necessity for governing or regulating apparatus such as would be required if the low pressure and high pressure compressor parts were operated by independent turbines. This is due to the fact that in the case of double rotation turbines the absolute speeds of the turbine rotors may vary without affecting the governing factor, which is thespeed of one shaft relative to the other. This results in the automatic balancing of the distribution ,of the load between the compressor parts when the load on the compressor varies.

By employing a double rotation turbine of the radial flow type it is possible, as will be evident from the drawing, to employ a highly efiicient multiple stage turbine without increasing the length of the apparatus as a whole as compared with the length of an apparatus in which the power is supplied by a much less efficient single stage turbine, and the use of multiple stage radial flow turbine structure does notincrease the overall diameter of the apparatus since a radial flow turbine of the double rotation type may be made with suificient stages to secure maximum eificiency without having the diameters of the rotors and the casing therefor exceed the the compressor parts.

Furthermore, the construction of the apparatus in accordance with the invention, with radial flow turbine rotors fixed in,overhung relation on the adjacent ends of the oppositely rotating shafts, permits a turbine driven compressor apparatus to be constructed with the minimum number of, shaft bearings and further permits the construction of the apparatus as a whole to be made with the utmost compactness and with the minimum weight. The compressor casings, being overhung at the sides of the main turbine casing, do not require separate supporting pedestals, thus reducing the weight of the structure,

diameters of 1,947,477 and the-central support provided by the base of the turbine casing portion of the housing structure avoids difliculties due to misalignment of bearings and shaft parts, which frequently arise in the case of apparatus supported. by separate pedestals or by a common base of large area under the entire apparatus.

, While for purposes of illustrating the invention the compressor apparatus has been shown as consisting of but two compressor parts, it is to be'understood that the invention applies equally to compressor installations in which additional compressor parts driven by separate means are employed. Consequently, the terms high pressure. and low pressure as herein employed with reference to the compressor parts are to be considered only in their relative sense, since the low pressure part in the apparatus illustrated may,-

within the scope of the invention, receive a precompressed medium from other independently driven compressor apparatus and the high pres,-

sure part may deliver the medium to additional compressor apparatus for compression to final pressure.

It will be evident that many changes in the specific form and arrangement of the parts of the apparatus may be made without departing from the invention, the scope of which is defined in the appended claims, which are to be construed as broadly as is consistent with the state of the prior art.

What I claim is:-

1. In turbine driven compressor apparatus, two compressor parts serially connected withrespect to flow of the medium to be compressed, each of said compressor parts comprising a rotatably mounted rotor member including a shaft, said shafts being in axial alignment and having adjacent inner end parts, and means for driving said members comprising a multiple stage double rotation radial flow .turbine having two rotors each fixed in overhung relation on the inner end part of a different one of said shafts.

2. In turbine driven compressor apparatus, housing structure providing a turbine casing and two compressor casings, said compressor casings extending from axially opposite sides of the turbine casing, two shafts rotatably mounted in axial alignment in said structure, a compressor rotor carried by one of said shafts in one of the compressor casings, a second compressor rotor carried by the other of said shafts in the other of the compressor casings, a multiple stage double rotation radial flow turbine for driving said compressor rotors, said turbine comprising two turbine rotors, one of the turbine rotors being fixed in overhung relation on the inner end of one of said shafts and the other of the turbine rotors being fixed in overhung'relation on the inner end of the other of said shafts, and conduit means connecting the compressor parts of the apparatus in series with respect to the flow of the medium to be compressed. I

3. In turbine driven compressor apparatus, housing structure providing a turbine casing and two compressor casings, said compressor casings being at axially opposite sides of the turbine casing and being supported by and overhung with'respect to the turbine casing, two shafts rotatably mounted in axial alignment in said structure, a compressor rotor carried by one of said shafts in one of the compressor casings, a second compressor rotor carried by the other of said shafts in the other of the compressor casings, a multiple) stage double rotation radial flow turw bine for driving said compressor rotors, said turbine comprising two turbine rotors, one of the turbine rotors being fixed in overhung relation on the inner end of one of said shafts and the other of the turbine rotors being fixed in overhung relation on the inner end of the other of said shafts, and conduit means connecting the compressor parts of the apparatus in series with respect to the flow of the medium to be compressed.

4. In turbine driven compressor apparatus,

housing structure providing a turbine casing and two compressor casings, said compressor casings extending from axially opposite sides of the tur bine casing, two shafts rotatably mounted in axial alignment in said structure, a compressor rotor carried by one of said shafts in one of the compressor casings, a second compressor rotor carried by the other of said shafts in the other .of the compressor casings, each of said rotors comprising a plurality of .rows of blades having radial discharge and arranged axially side by side to provide a plurality of compression stages for each rotor, conduit means for connecting the outlet of one of said compressor casings with the inlet of the other of said compressor casings, and means for driving said shafts comprising two multiple stage radial flow turbine rotors each having a plurality of rows of moving blades, said rotors being fixed in overhung relation on the adjacent ends of said shafts'within said turbine casing and cooperating to provide a double rotation radial flow turbine.

5. In turbine driven compressor apparatus, a low pressure compressor part and a high pressure compressor part serially connected with respect to flow of the medium to be compressed, each of said compressor parts comprising a shaft and a rotor for compressing in a plurality of ing said rotors independently of each other,

whereby to permit them to operate at different absolute speeds, comprising a multiple stage double rotation radial flow turbine having two rotors each fixed in overhung relation on the inner end of a different one of said shafts.

6. In turbine driven compressor apparatus, a housing structure providing a turbine casing and two compressor casings, said compressor-casings being at axially opposite sides of the turbine casing and being supported in overhung relation by the turbine casing, two shafts rotatably mounted in axial alignment in said structure, a low pressure. compressor rotor carried by one of said shafts in one of the compressor casings, a high pressure compressor rotor carried by the other of said shafts-in the other of the compressor casings, each of said rotors comprising a plurality of axially side by side compression stages and the low pressure rotor having a larger mean diameter than the'mean diameter of the high pressure rotor and being adapted to rotate at a speed lower than that of the high pressure rotor, conduit means providing for flow of the medium to'be compressed from the highest pressure stage multiplestage double rotation radial flow turbine having two cooperating rotors, a. low pressure compressor part associated with said turbine and having a rotor driven by one of the turbine rotors, a high pressure compressor part associated with said turbine and having a. rotor driven by the other of the turbine rotors, and means providing a connection for flow of fluid to be compressedfrom the outlet of the low pressure compressor part to the inlet of the high pressure compressor part. I v

ALF LYSHOLM.

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