CH641877A5 - METHOD FOR MULTI-STAGE COMPRESSION OF GASES AND MULTI-STAGE COMPRESSOR FOR CARRYING OUT THE METHOD. - Google Patents

Description

The object of the invention is to meet the following requirements: The first compressor stage 4 is always a turbo compressor.

fulfill: sor and the last compressor stage 8 always a screw

1. Large control range, 35 pressor or another displacement compressor. The middle

2. steep characteristic, ren stages 7 can be omitted depending on the application

3. good efficiency at full and partial load, or will be turbo or displacement compressors.

4. no suddenly occurring operating limits, in Figure 1 is a diagram for an arrangement with three

5. small effort, compressor stages in the order of turbo, screw,

6. Optimal adaptation of the compressor stages to the 40 screw compressors shown. The branching gearbox is subject to volume, pressure and temperature conditions. is constructed in the exemplary embodiment such that a zen

The invention fulfills these requirements with the help of a gear wheel 2 and pinion 3, the individual compressor stages 4, 7, 8

Process for multi-stage compression of gases in which are driven at optimal speed.

Way that the entire compression process is based on an exemplary and advantageous arrangement of the compression

is divided into several stages so that the individual compressor in the 45 ters is outlined in Figure 2. Compressor stages 4.7 and 8

Best point to be operated and the lowest Lei are flanged to the gear housing 11. Depending on the purpose

power consumption achieve that at partial load only the first and moderate all compressor stages on the engine 1

the last compressor stage is operated under the side facing away from the nominal load or both on this as well as on the same conditions, while the pressure on the other side of the gearbox is mounted on which the

Ratios, the volume flows and thus the optimum motor so connected to the gearbox via a clutch 10 drove consistently at the middle stages and that at La-. In the feed line upstream of the first compressor stage 4 there is a change in quantity in the first compressor - a throttle body for stage 5 and volume control and in the last stage the pressure adjustment to the supply. This throttle body can e.g. a swirl throttle or a bracer take place. It is preferably provided that be for simple throttle valve.

The first compressor stages are flow compressors, in particular 55 The gas enters the compressor via combined silencers and filters of their radial type, and in the last stage 12 they enter the compressor. The entire compressor system is built on a displacement compressor, for example a screw-type joint, with a common base frame 13. The oil container 14 can be integrated in this more densely used, all for the optimum loading base frame. Except-

driven by a branching gear with several exits, all the coolers 6 and other auxiliary units, which are driven in the gears and are not shown in sequence in terms of flow, the pipelines, control elements

switches pipeline connected. elements, oil pumps with arranged on the base frame.

According to the invention, a multi-stage compressor for the system can be provided with a sound hood. Implementation of this method, characterized in that FIG. 3 shows as an example the behavior of a system that is constructed in accordance with the flow compressor and displacement compressor, FIG. For others according to the invention connected in series and due to pipe 65 divisions there is an analogous behavior. Connections are connected and carried by a branching gear on the ordinate on a logarithmic scale with at least two drive shafts each compressor stage with the pressure behind the system in bar. Same ordinate differences - the speed that is optimal for them. borders mean the same pressure conditions. On the abscissa

641877

the intake mass flow based on the nominal mass flow mo is shown in%. The curves shown show the pressures in front of and behind the individual compressor stages depending on the partial load-mass flow ratio in • m / m0.

In Figure 3:

P0 the pressure in front of the throttle bodies 5,

P) the pressure in front of the first compressor stage 4 and behind the throttle element 5,

P2 the pressure behind the first compressor stage 4 and before the second compressor stage 7,

P3 the pressure behind the second compressor stage 7 and before the third compressor stage 8 and

P4 the pressure behind the third compressor stage 8, which is required by the consumer.

The arrow d indicates that the final pressure P4 can fluctuate depending on the consumer. The distance e indicates the pressure drop at the throttle element 5 from P0 to P]; this pressure drop increases with partial loads. The sections a and b characterize the pressure increase in the first compressor stage 4 and the second compressor stage 7.

The pressure ratio P3P2 with which the gas is compressed by this stage remains constant at every operating point. The distance c, on the other hand, represents the pressure ratio with which the last stage is applied. This increases with partial load.

The regulation at partial load can be done by throttling the intake flow. The mass flow becomes smaller by lowering the pressure at the same volume flow. A second way is to swirl the intake flow to the turbocompressor, thereby reducing both the mass flow and the pressure ratio of the turbocompressor. In the first case, the throttle element 5 is a throttle valve, while in the second case a swirl throttling is required. When controlling with a swirl throttle, the partial load efficiency is better than with simple throttling, since less power has to be applied for the compression in the turbo compressor.

The volume flow to be processed by the middle stages remains constant at partial load. Since the pressure ratio in the middle compressor stages also remains constant, the operating point of these stages does not change during the control. They also work at partial loads with maximum efficiencies, optimal throughputs and speeds.

The last stage works with different pressure ratios. The suction volume also remains the same and 15 generates the pressure required by the consumer. A compressor with a steep characteristic curve is required for such operating modes, which is why a displacement compressor is always used as the last stage.

So that the adaptation to the consumer is possible even with small partial loads, the pressure ratio of this compressor is designed to be small at the nominal point, for example for dry rotators between 1 and 2.5. Pressure fluctuations caused by the consumer do not affect the operation of the front stages. Because of the large volume 2s flows at the inlet to the compressor system - the pressure is still low here - turbo compressors are expediently used as the first stages, since they are best suited to all types of compressors for these operating conditions. Because of the arrangement according to the invention, they work optimally for all load conditions. There is no danger that the surge limit, the instability limit or the swallowing limit will be reached.

C.

2 sheets of drawings

Claims (10)

641877 2 PATENT CLAIMS in general from compressor stages of the same type, 1. Process for the multi-stage compression of gases, bo, screw or piston compressors, in particular oil-free air, characterized in that the multi-stage turbocompressor has been divided into several stages with high absorption capacity in the area of large volume flows due to its entire compression process, that the individual compressors operated at their best. Multi-stage piston compressors are set in particular that at partial load only the first and the last compressor range of smaller volume flows for higher final pressures are set under conditions that have changed compared to the nominal load. are operated while the pressure ratios, the multi-stage screw compressors have in the middle flow and thus optimal operation found their place in the medium io lumen and pressure range. Stages remain the same, and that when the load changes, the quantity of different types of compressors is adapted in the first compressor stage and in the last to the different volume and pressure ranges Level of pressure adjustment to the consumer takes place. decided from an economic point of view. Tech 2. The method according to claim 1, characterized, nisch it is possible to compressors of a certain type that flow compressors for the first compressor stages, ins-15 also for a radial type other than that for the most suitable pressure, in particular a radial type compressor and in the last and volume range build, such a solution requires a displacement compressor stage, for example a screw but always more effort and is therefore only used in special compressor, all of which are justified for the optimal case. len operation via a branching gear with several- The piston compressor type is driven in the area of smaller outlets and in terms of flow behind one another- volume flows or very high pressures are well suited. other connected pipeline connected. Large volume flows and not too high pressures are 3. Multi-stage compressor for carrying out the Verden usually generated with turbo compressors. In the door driving according to claim 1 for the compression of gases, in particular compressors, a distinction is made between compressors of radial and special oil-free air, characterized in that the stria-axial type. The radial type is more for the higher flow compressors (4) and displacement compressors (7,8) flow pressures and the axial type more for the large volumes in series and connected by pipe flows in the application area of the turbocompressor units , and set over a branching gear. (2,3) with at least two output shafts each compressor - the advantages of turbo compressors are a relatively small speed with which the optimal speed is driven. Construction work for large volume flows. Turbocompressor 4. Compressor according to claim 3, characterized gekennzeich- 30 depending on the pressure different Volu-net that the number of compressor stages max. 4 amounts that process menstreams. They have a so-called «flat first stage always a turbocompressor (4), the last stage a characteristic curve», their working area becomes small volume flow displacement compressors (8) and that the intermediate one. stages due to the “surge limit” or “instability limit” stages are turbo or displacement compressors. and towards large volume flows through the «swallowing 5. Compressor according to claims 3 and 4, thereby limited 35 limits. For effective pressure generation in indicates that the last compressor stage (8) a pressure turbo compressor generates high flow rates of 1 to 2.5. required that only with larger volume flows or high 6. Compressor according to claims 3 to 5, thereby ge speeds can be realized. For small volu-indicates that the compressor stages (4,7,8) flying to the flow of men must have the flow cross-sections flanged for the high gear (2,3). 40 speeds become very low and the friction loss 7. Compressor according to claims 3 to 6, thereby gestures on the surfaces are large. The efficiency of the characterizes that between the compressor stages (4, 7, 8) turbocompressor, at least one cooler (6) is therefore arranged for smaller volume flows. . worse. High speeds require the usual 8. Compressor according to one of claims 3 to 7, drive motors complex gears. The efficiencies are characterized by the fact that a throttle orifice point is provided for the control in turbo compressors with a good control element (5) in the intake line. speed, i.e. wide map not as high as with compressors, 9. Compressor according to claims 3 and 8, characterized- which were specially optimized for an operating point, characterizes that the throttle element (5) is a swirl throttle. The screw compressor design has its application 10. Compressor according to claims 3 to 9, characterized in the range of medium volume flows and pressures between that all plant parts on a common so see piston compressors and turbo compressors. Since the screw base frame (13) is installed. compressor have no reciprocating masses like piston compressors, they can be operated at higher speeds than these. The screw compressor has an almost vertical characteristic, i.e. The final pressure is almost not the subject of the invention are a method for more depending on the volume flow. A machine with a lower-level compression of gases, in particular oil-free air, right-hand characteristic curve can only be poorly operated with a fixed number of drives and a multi-level compressor for carrying out the regulation; throttling of the medium drawn in. In return there are volume flows in the range of allowed only slightly lower power consumption at part load. 5,000 to about 50,000 m3 / h and pressure ratios greater than desired, a compressor with a large 5 is considered in many cases. First and foremost, the invention relates to a 60 control range and a “steep characteristic curve”, so that the pressure on the oil-free compression of air and gases, partial loads cannot decrease and, in addition, the efficiency factor should be increased both by us and instead of by the oil-free compression Nominal load as well as partial load efficiency compressors with oil or liquid injection can be used well. The work area must not be suddenly hit. The driving instabilities (above all, the limited instabilities (e.g. surge limit)) are limited electric motors, but it can also be a 65 in its place. The effort for this should be as low as possible. Turbine, an internal combustion engine or a drive motor. To meet these requirements is a one-stage changer design. dense and also with the previously known multi-stage Multi-stage compressors are known. They cannot be implemented in the compressor. 3 641877 Compressible media change their volume greatly. The number of compressor stages preferably increases in pressure. The volume flow changes accordingly. 4. The first stage is then always a turbocompressor, according to the pressure increase during the compressor process. while the last stage is a displacement compressor. The energy consumption of the working medium for the compression between the intermediate stages is turbo or displacement is temperature dependent. For small energy supplies, i.e. 5 compressors. the medium has to be cooled in order to achieve good efficiency. A The last compressor stage generates the optimal compression process when compressing, therefore requires a pressure ratio of 1 to 2.5 adapted to the different volume flows in each case without injection cooling in nominal operation. the compressor stages and intermediate cooling. The compressor stages are preferably flying on one With multi-stage screw compressors, the above i0 gearbox is flanged and between the compressor stages To meet requirements, the construction effort would be very large, at least one cooler would be arranged. especially for the first stages with large volume flows. For the regulation of the compressor is preferably one Multi-stage turbocompressors have a throttling device in the outlet line if the characteristic curve is steep. This just a smaller work area. Intercooling is only a throttle element, preferably a swirl throttle. difficult or very expensive, as well as the operation of the 15 Finally, it can be provided that all parts of the system individual stages at optimal speeds. The printer is mounted in the compressor on a common base frame right next to the displacement compressors. hung in one stage with turbo compressors smaller. The method according to the invention, the arrangement and half a relatively large number of stages are therefore necessary. A branching gearbox - the construction of the compressor system results in an optimal one for adapting the respectively optimal speeds for the 20 operation in the partial load range and efficiencies, which is very complex for such individual stages and would have previously been unknown to large ranges. Since the map consume stungen. Instability limits cannot be exceeded, not even due to sudden operating limits. avoid. is also extremely safe operation of the A combined arrangement of turbo compressors is also possible. and screw compressors as in US-PS 25 An embodiment of the invention is based on the 36 40 646 or FR-PS 13 97 614 can be proposed, drawing explained in more detail below. It can not meet the requirements. Since turbocompressor Figure 1: the schematic structure of a multi-stage and screw compressor on a shaft with the same rotary compressor in perspective, Figure 2: a schematic longitudinal section of the compressor earths for the volume and 30 plants concerned with this invention Pressure range as well as in the case of the multi-stage compressors FIG. 3: An image of the characteristic curve for the comparator type according to the invention is not possible. drive and the corresponding compressor system.