DE102009009731A1 - Radial compressor e.g. two-stage radial compressor, has intermediate space sectionally formed between inner and outer housings, where intermediate pressure that prevails in space is higher than ambient pressure acting on outer housing - Google Patents

Abstract

The compressor has a compression stage for increase of pressure of working fluid i.e. air, from inlet pressure (pein) to outlet pressure (paus). Fluid inlets (2.1, 3.1), fluid outlets (2.3, 3.3), an outer housing (2) and an inner housing (3) are provided, where an intermediate space (4) is sectionally formed between the inner housing and the outer housing. Intermediate pressure (pzwischen) prevails in the intermediate space during an operation of the compressor, where the intermediate pressure is higher than ambient pressure (pinfinity) acting on the outer housing from outside. An independent claim is also included for a method for increase of pressure of working fluid from inlet pressure to outlet pressure by a radial compressor.

Description

The The invention relates to a radial compressor having a fluid inlet, at least one compression stage for increasing the pressure of a working fluid, in particular a gas, from an inlet pressure to an outlet pressure, a fluid outlet, and a housing.

at a radial compressor flows generally the working fluid radially through a fluid inlet in a housing, is fed axially to an impeller of a compression stage, from this radially outward diverted, and leaves the housing through a fluid outlet having an outlet pressure higher than is an inlet pressure at the fluid inlet. For multi-stage centrifugal compressors the working fluid behind a compression stage becomes serpentine the next Supplied compression stage. By Radial compressors can higher pressures compared to axial compressors, for example in the range be generated between 50 and 150 bar.

The Pressure increase of the working fluid, such as air, takes place usually - too at between individual compression stages arranged intermediate cooling - under Temperature increase, so that the fluid outlet at the same time as the partially high outlet pressure and a high heat input through the hot Working fluid is charged. However, the heat input lowers the Strength of the high pressure loaded fluid outlet, so that this disadvantageously must have correspondingly greater wall thicknesses. By the heat input Induced temperature stresses in the fluid outlet additionally reduce adversely the sustainable outlet pressure. The same applies accordingly for one Compression section of the housing, which surrounds a compression stage.

changing Heat inputs, like For example, with heavy load changes or short on and shut-down connected lead as well too unfavorable Thermal stresses in the housing of the radial compressor.

task The present invention is therefore a radial compressor to improve.

These The object is solved by the features of claim 1. claim Fig. 18 illustrates a method of operating such a radial compressor under protection, the dependent claims relate to advantageous developments.

One Radial compressor according to the present invention has a fluid inlet, For example, one or more suction, one or more Compression levels to increase the pressure a working fluid, for example a gas, in particular of Air, from an inlet to an outlet pressure, a fluid outlet, for example, one or more discharge nozzles, and a housing. A Compression level can, for example, one or more open or include closed 2D or 3D wheels and with a subsequent compression stage communicate directly or via intercooling.

According to the invention will now proposed, the pressure and temperature load on two housing shells to distribute. For this purpose, the housing of the radial compressor Outer casing and a inner housing on, between inner and outer housing at least in sections, a gap is formed. This one is like this designed so that in operation there is an intermediate pressure higher than one from the outside acting on the outer housing Ambient pressure is.

at a single-shell housing According to the prior art are the compressed, hot working medium and the case in contact with the case the considerable pressure difference between the outside pressure on him and a prevailing in his interior Operating pressure generally exceeding the axial length of the Compression stage (s) increases and at the fluid outlet the outlet pressure equivalent.

On the inner casing a radial compressor according to the invention, which preferably with already at least partially compressed Working medium is in contact and this leads, however, affects only the lower pressure difference between acting from the inside to the inner housing Working pressure and the intermediate pressure, which is higher than the ambient pressure is. Thus, the inner case, the the working medium leads, therefore, it is in contact with it and thereby thermally is applied, mechanically only with a smaller pressure difference loaded and can therefore advantageously thin-walled and / or from cheaper Material lower strength can be formed.

The Outer housing one radial compressor according to the invention, which does not prefer with hot Working medium, in particular in the area of a compression output stage and / or the fluid outlet is in contact and therefore only one undergoes lower thermal load, is mechanically with the Pressure difference between the intermediate pressure and the outside it loads the ambient pressure. Thus, the outer casing becomes both thermally and mechanically less burdened and can accordingly also advantageous thin-walled and / or cheaper material lower strength can be formed.

Thereby is inventively the pressure and Temperature load distributed to the inner and the outer housing.

Prefers takes the inner case essentially the temperature load, the outer casing essentially the pressure load on. As a result, for example, the threat of a hot outer casing and / or one from the outside unrecognizable incipient failure of the pressure housing reduced. For this purpose, the gap in a preferred embodiment is so designed so that the difference between intermediate and working pressure in terms of amount less is the difference between intermediate and ambient pressure, i. e. the outer housing with a higher one Pressure difference is charged as the thermally higher loaded inner housing.

In The rule is the working pressure prevailing in the radial compressor between the inlet and outlet pressures and increases longitudinal the radial compressor, in particular in the compression stages. Advantageously, therefore, the intermediate pressure between the Inlet and outlet pressure. In a preferred embodiment corresponds the gradient of the intermediate pressure in the axial longitudinal direction of the radial compressor essentially the gradient of working pressure, so that on the inner housing in the axial direction everywhere essentially the same pressure difference works. Likewise the intermediate pressure, however, over the axial longitudinal direction of the radial compressor also have a different course, in particular in Be essentially constant or substantially linear in the Increase gap or decrease.

Of the Gap can be permanent or at least in operation with a fluid filled be, which is present at the intermediate pressure. In particular, it can be thereby act to be compressed and / or compressed working fluid. For example, if the working fluid is already at the fluid inlet an inlet pressure that over from the outside on the case of the radial compressor acting ambient pressure, so can in or nearby the fluid inlet working fluid branched off and the space supplied be, so that there prevails the intermediate pressure according to the invention. Additionally or Alternatively, already compressed working fluid, which at correspondingly higher Pressure exists, for example, between two compression levels and / or taken in or after the fluid outlet and the gap supplied become. If it is taken after the last compression stage, it is beneficial to it - for example in an intermediate cooling - to cool before it fed to the gap so as to reduce the thermal load on the outer casing.

Especially For this purpose, the gap may be formed so that he constantly or flows through the fluid at least during operation. This can be advantageous Warmth, the from the outside surface of the inner housing is discharged to the intermediate space, are discharged with the flowing fluid. additionally can by appropriate flow guidance of Intermediate pressure curve in the desired Way along be adjusted in the axial direction. Likewise However, the gap also resistant to a fluid in the Intermediate pressure filled be.

One Another advantage of a filled with stagnant or flowing fluid gap can lie in its insulating effect. Especially if it is a poorly thermally conductive Gas, such as air, is beneficial by this fluid a heat transfer reduced between the inner and outer housing.

Around To reduce a thermal load on the outer housing may be advantageous a cooling be provided of the intermediate space. For example, as explained above, Fluid, which flows through the intermediate space before, for example, indirectly by means of a heat exchanger or directly by heat emission to the environment, cooled become.

Especially through a chilled and / or poorly heat-conducting Fluid in the space can the inner and the outer housing at least partially thermally decoupled from each other in sections be. Preferably, thermal bridges between Inner and outer housing, for example Webs, flanges, seals or the like between indoor and Outer case for this only a small cross-section and / or are of poor heat-conducting Material produced. additionally or alternatively, a heat insulation on the outside surface of the Inner and / or inner surface be arranged of the outer housing.

In conventional processes, the highest working fluid temperature occurs along with the highest working pressure in the fluid outlet, which may include, for example, one or more fluid collection compartments and / or one or more exit stems. A division of the pressure and temperature load on two housing shells is therefore particularly advantageous in this area. Therefore, in a preferred embodiment, the inner housing has a downstream of the or the compression stage (s) disposed fluid outlet, which discharges the working fluid from the centrifugal compressor. This fluid outlet of the inner housing at least partially surrounds a fluid outlet of the outer housing, so that the intermediate space between the fluid outlet of the outer housing and the fluid outlet of the inner housing is formed.

Also within a compression stage or between two compression stages, especially before an intermediate cooling, can already high working pressures and working fluid temperatures occur. Additionally or alternatively therefore the inner case have a compression portion which at least partially one or more at a working pressure to be flowed through the compression stage surrounds. The outer casing has in this preferred embodiment a compression portion at least partially the compression portion of the inner casing surrounds so that the space between the compression section of the outer casing and is formed the compression portion of the inner housing. The can Compression sections of the interior and / or Outer casing too only a part of the compression levels or a compression level only partially surrounded. For example, several compression levels be included in a compression section of an inner housing, in turn only from a compression stage, during operation, a higher working pressure and / or a higher one Working fluid temperature occurs from a compression section surrounded by an outer casing is to get this higher Distribute pressure and temperature load on the inner and outer housings.

Additionally or Alternatively, the outer housing also a fluid inlet at least partially one of Surrounding working fluid at inlet pressure to fluid inlet of the inner housing, such that the space between the fluid inlet of the outer housing and the fluid inlet of the inner housing is trained. As a result, in particular working fluid in or branched off before entering a first compression stage and supplied to the intermediate space become. additionally this extends the possibilities a fluid flow targeted to adjust in the space.

As can be seen from the above, the gap according to the invention between inner and outer housing so equally in a fluid inlet, a compression section and / or a Be formed fluid outlet. This space can be consistent with each other communicate. equally However, it is also possible, the Dividing space into separate gap sections. This can in particular the sealing of inner housing, outer housing or To simplify the gap.

Especially Advantageously, the inventive division of the pressure and Temperature load on two housing shells for radial compressors whose working pressure is in the range between 30 bar and 170 bar, preferably between 50 bar and 150 bar and especially is preferably between 60 bar and 140 bar, and / or their working fluid temperature in Fluid outlet larger or equal to 300 ° C, preferably larger or equal to 350 ° C and particularly preferably larger or equal to 600 ° C is.

by virtue of the proposed division of the pressure and temperature load on two housing shells and the associated lower thermal load of the outer housing also At high working fluid temperatures can ge before geous enough or several compression stages adiabatic or quasi-adiabatic trained be. equally can be a heat source, in particular a thermal store and / or one, in particular catalytic, combustion, thermal with at least one compression stage be coupled and heat enter in this. This allows also other processes, in particular without or with less intercooling or even heat be driven in the radial compressor.

Further Advantages and features emerge from the subclaims. For this shows, partially schematized, the only one:

1 A radial compressor according to an embodiment of the present invention.

1 shows a two-stage radial compressor according to an embodiment of the present invention. This includes a drive shaft 1 , on the two compressor wheels 1.1 . 1.2 are arranged.

The drive shaft 1 with the two wheels 1.1 . 1.2 is rotatable in an inner housing 3 stored, which has a fluid inlet 3.1 for the axial supply of air as working fluid to the first impeller 1.1 having. The first impeller 1.1 In the radial direction deflected while compressed air is in a in the inner housing 3 trained flow channel serpentine like the second impeller 1.2 fed, which further compresses the air and this deflects radially outward. The air, which heats up strongly, then from a fluid outlet 3.3 of the inner casing 3 dissipated.

The first or second impeller 1.1 . 1.2 forms together with the associated flow guide in the inner housing 3 a first and second compression stage, which together in a compression section 3.2 of the inner casing 3 are formed. In the compression stages, the air is supplied from an inlet pressure p _a at the fluid inlet 3.1 of the inner casing 3 , with which the air is supplied to the radial compressor from a pre-process, not shown, and in the embodiment 20 bar, to one over the axial length of the Radialkompres sors rising working pressure p _work compressed so that at the fluid outlet 3.3 of the inner casing 3 Finally, there is an outlet pressure p _out of 100 bar.

The inner case 3 is in an outer casing 2 added, leaving a compression section 2.2 of the outer casing 2 the compression section 3.2 of the inner casing 3 surrounds and a fluid outlet 2.3 of the outer casing 2 with a thermally insulating seal, not shown, the fluid outlet 3.3 of the inner casing 3 surrounds. A fluid inlet 2.1 of the outer casing 2 is formed so that the air with the inlet pressure p _a of the preliminary process fluid inlet 3.1 of the inner casing 3 is supplied. Thus, between the outer and the inner housing 2 . 3 , in particular between their compression sections 2.2 . 3.2 a gap 4 educated.

This gap 4 is filled in operation with air at an intermediate pressure p _between , which corresponds substantially to the inlet pressure P _a . For this, the gap 4 , for example, an in 1 only indicated gap, with the fluid inlet 2.1 of the outer housing communicate. Similarly, the gap 4 also filled with another fluid, for example, a poorly heat-conducting inert gas, and be formed substantially fluid-tight. In a further modification, not shown, the gap 4 also of highly compressed air with the outlet pressure p _out of the fluid outlet 3.3 of the inner casing 3 branched off and cooled by an intermediate cooling, not shown, are flowed through.

Thus prevails in the space 4 always an intermediate pressure p _between which lies in the above-described embodiments, from the inlet pressure p _and the discharge pressure _of p. From the outside, the ambient pressure p _∞ of 1 bar on the outer housing 2 ,

While now in a conventional radial compressor, in which, for example, the outer housing 2 in 1 missing, then on the remaining housing 3 at the fluid outlet 3.3 the pressure difference p _out - p _∞ acts and the housing simultaneously at the fluid outlet 3.3 is thermally acted upon by the strongly heated air due to the compression, according to the invention, the inner housing is acted upon only with the lower pressure difference p _from - p _between . That with the pressure difference _between p - p _∞ acted outer casing 2 however, is through the gap 4 thermally substantially from the inner housing 3 decoupled and does not come in contact with the hot, compressed air. Thus, both inner and outer housing can be advantageously formed thin-walled.

1

drive shaft

1.1 1.2

Wheel

2

outer casing

2.1

fluid inlet

2.2

compression section

2.3

fluid outlet

3

inner housing

3.1

fluid inlet

3.2

compression section

3.3

fluid outlet

4

gap

p _a

inlet pressure

p _off

CDP

p _between

intermediate pressure

p _work

working pressure

Claims (18)

Radial compressor with a fluid inlet ( 2.1 . 3.1 ), At least one compression stage to increase the pressure of a working fluid, in particular of a gas (from an inlet pressure p _a) (a discharge pressure (P _out), a fluid outlet 2.3 . 3.3 ), and a housing having an outer housing ( 2 ) and an inner housing ( 3 ), wherein between inner and outer housing at least partially a space ( 4 ) is formed in which in operation an intermediate pressure (p _between ) prevails, which is higher than an externally acting on the outer housing ambient pressure (p _∞ ). Radial compressor according to claim 1, characterized in that the difference (p _work - p _between ) of the intermediate pressure (p _between ) with respect to a working from the inside to the inner housing working pressure (p _work ) at least in sections amount is less than a difference between the intermediate and ambient pressure (p _between - p _∞ ). Radial compressor according to one of the preceding claims, characterized in that the intermediate pressure (p _between ) between the inlet and outlet pressure is (p _a ≤ p _between ≤ p _off ). Radial compressor according to one of the preceding claims, characterized characterized in that, in operation, the gap is filled with a fluid, in particular to be compressed and / or compressed working fluid at least partially filled is. Radial compressor according to claim 4, characterized that during operation of the gap is traversed by the fluid. Radial compressor according to one of the preceding claims, characterized characterized in that a cooling of the intermediate space is provided. Radial compressor according to one of the preceding claims, characterized characterized in that the inner and the outer housing at least in sections thermally substantially decoupled from each other. Radial compressor according to one of the preceding claims, characterized in that the outer housing has a downstream of the at least one compression stage arranged fluid outlet ( 2.3 ) which at least partially comprises a fluid outlet to be flowed through by working fluid compressed to the discharge pressure (US Pat. 3.3 ) of the inner housing, and the space ( 4 ) is formed between the fluid outlet of the outer housing and the fluid outlet of the inner housing. Radial compressor according to one of the preceding claims, characterized in that the outer housing has a compression section ( 2.2 ) which at least partially comprises a compression section ( 3.2 ) surrounds the inner housing, which in turn at least partially surrounds at least one of working fluid to be flowed through at working pressure compression stage, and the gap ( 4 ) is formed between the compression portion of the outer case and the compression portion of the inner case. Radial compressor according to one of the preceding claims, characterized in that the outer housing has a fluid inlet ( 2.1 ) which at least partially comprises a fluid inlet to be flowed through by working fluid at inlet pressure ( 3.1 ) of the inner housing, and the space between the fluid inlet of the outer housing and the fluid inlet of the inner housing is formed. Radial compressor according to one of the preceding claims, characterized in that the radial compressor is a single or multi-shaft compressor is. Radial compressor according to one of the preceding claims, characterized characterized in that the outlet pressure is greater than or equal to 30 bar, in particular bigger or is equal to 50 bar and in particular greater than or equal to 60 bar. Radial compressor according to one of the preceding claims, characterized characterized in that the outlet pressure is less than or equal to 170 bar, in particular less than or equal to 150 bar and in particular smaller or equal to 140 bar. Radial compressor according to one of the preceding claims, characterized in that the temperature of the working fluid in the fluid outlet is greater than or equal to equal to 300 ° C, especially greater or equal 350 ° C and especially larger or equal to 600 ° C is. Radial compressor according to one of the preceding claims, characterized in that at least one compression stage is adiabatic or quasi-adiabatic is. Radial compressor according to one of the preceding claims 1 to 14, characterized in that a heat source, in particular a thermal storage and / or one, in particular catalytic, combustion, thermally coupled to at least one compression stage. Radial compressor according to one of the preceding claims, characterized characterized in that the working fluid comprises air. A method for increasing the pressure of a working fluid from an inlet pressure (p _a) to a discharge pressure (P _out) by means of a radial compressor according to one of the preceding claims, wherein an intermediate pressure (p _between) is impressed in the intermediate space during operation, which is higher than an externally to the outer housing acting ambient pressure (p _∞ ) is.