阅读说明：本技术 用于对至少两级的压缩空气发生器进行冷却的冷却装置和方法 (Cooling device and method for cooling at least two stages of compressed air generators ) 是由 F·G·克劳斯 U·托马斯 M·席尔 于 2020-01-24 设计创作，主要内容包括：本发明涉及一种用于至少两级的压缩空气发生器(01)的冷却装置。所述冷却装置包括布置在第一压缩机级与第二压缩机级(02、03)之间的中间冷却器(04)、布置在所述第二压缩机级(03)之后的后冷却器(05)以及从所述压缩空气发生器(01)的其他部件处吸收热量的部件冷却器(08)。冷却剂回路包括主冷却器(07),该主冷却器的冷侧向所述中间冷却器(04)、后冷却器(05)和部件冷却器(08)的各自的冷却剂入口并行地输送经过冷却的、具有低温的冷却剂,并且该主冷却器的热侧接收在所述中间冷却器(04和后冷却器(05)的各自的冷却剂出口处并行地流出的经过加热的、具有高温的冷却剂。所述部件冷却器(08)的冷却剂出口被连接到所述中间冷却器(04)和/或后冷却器(05)的供给入口(12)上。所述供给入口(12)在所述冷却剂入口与所述冷却剂出口之间布置在以下位置处,在所述位置处所述中间冷却器(04)中或者所述后冷却器(05)中的冷却剂的中间温度相当于在所述部件冷却器(08)处的冷却剂的流出温度±20％。此外,本发明涉及一种用于对至少两级的压缩空气发生器进行冷却的方法。(The invention relates to a cooling device for an at least two-stage compressed-air generator (01). The cooling device comprises an intercooler (04) arranged between the first and the second compressor stage (02, 03), an aftercooler (05) arranged after the second compressor stage (03), and a component cooler (08) which absorbs heat from other components of the compressed air generator (01). The coolant circuit comprises a main cooler (07), the cold side of which conveys cooled coolant having a low temperature in parallel to respective coolant inlets of the intercooler (04), the aftercooler (05) and the component cooler (08), and the hot side of which receives heated coolant having a high temperature which flows out in parallel at respective coolant outlets of the intercooler (04) and the aftercooler (05), the coolant outlet of the component cooler (08) being connected to a supply inlet (12) of the intercooler (04) and/or the aftercooler (05), the supply inlet (12) being arranged between the coolant inlet and the coolant outlet in a position in which an intermediate temperature of the coolant in the intercooler (04) or in the aftercooler (05) corresponds to an outflow of the coolant at the component cooler (08) The temperature is +/-20%. The invention further relates to a method for cooling at least two stages of compressed-air generators.)

1. A cooling device for an at least two-stage compressed-air generator (01), the cooling device comprising:

-a liquid-cooled intercooler (04) arranged between the first and second compressor stages (02, 03) for cooling the pre-compressed air discharged by the first compressor stage (02) before it flows into the second compressor stage (03);

-an aftercooler (05) cooled with liquid, arranged after the second compressor stage (03), for cooling the air compressed thereby;

-a liquid-cooled component cooler (08) which absorbs heat from other components of the compressed-air generator (01);

-a coolant circuit with a main cooler (07), the cold side of which feeds a cooled, low-temperature coolant in parallel to the respective coolant inlets of the intercooler (04), aftercooler (05) and component cooler (08), and the hot side of which receives a heated, high-temperature coolant flowing out in parallel at the respective coolant outlets of the intercooler (04) and aftercooler (05);

characterized in that a coolant outlet of the component cooler (08) is connected to a supply inlet (12) of the intercooler (04) and/or the aftercooler (05), wherein the supply inlet (12) is arranged between the coolant inlet and the coolant outlet at a location at which an intermediate temperature of the coolant in the intercooler (04) or in the aftercooler (05) corresponds to an outflow temperature of the coolant at the component cooler (08 ± 20%.

2. A cooling arrangement according to claim 1, characterised in that a heat exchanger (09) in the coolant circuit is interposed between the respective coolant outlets of the intercooler (04) and the after-cooler (05) and the hot side of the main cooler (07).

3. A cooling arrangement according to claim 1 or 2, characterised in that the main cooler (07) is a water-air-cooler or a water-cooler or a combined cooler with water and air optionally as cooling medium.

4. A cooling arrangement according to claim 3, characterised in that the main cooler (07) comprises a blower (11).

5. A cooling arrangement according to any one of claims 1-4, characterised in that the intercooler (04) and/or the aftercooler (05) has a plurality of supply inlets (12) to which the coolant can optionally be fed from a coolant outlet of the component cooler (08).

6. A cooling arrangement according to claim 5, characterised in that between the coolant outlet of the component cooler (08) and the feed inlet (12) a distributor unit is arranged, which under temperature control supplies the feed inlet (12) at which the intermediate temperature of the coolant in the intercooler (04) or aftercooler (05) is closest to the outflow temperature of the coolant at the component cooler (08).

7. A cooling arrangement according to any one of claims 1-6, characterised in that at least the intercooler (04), the aftercooler (05), the component cooler (08), the heat exchanger (09), the first and second compressor stages (02, 03) and the electronic control unit are arranged inside a common apparatus housing.

8. A method for cooling at least two stages of a compressed-air generator (01), comprising the steps of:

-leading the cooling medium in the coolant circuit through a main cooler (07) and through a first liquid-cooled intercooler (04) connected in series with the main cooler (07), which thereby cools air pre-compressed by a first compressor stage (02);

-leading the cooling medium in the coolant circuit through an after-cooler (05) also connected in series with the main cooler (07) and in parallel with the intercooler (04), which after-cooler thereby cools the air recompressed by the second compressor stage (03);

-feeding the cooling medium cooled in the main cooler (07) to a liquid-cooled component cooler (08) which absorbs heat from other components of the compressed-air generator (01);

characterized in that the heated cooling medium flowing out of the component cooler (08) is fed into the intercooler (04) and/or the aftercooler (05) via a feed inlet (12), wherein the feeding takes place in the intercooler (04) or aftercooler (05) at a location (12) at which the intermediate temperature of the coolant in the intercooler (04) or aftercooler (05) corresponds to the outflow temperature of the coolant at the component cooler (08 ± 20%.

9. A method according to claim 8, characterised in that the cooling medium heated in the intercooler (04) and in the after-cooler (05) is fed to a heat exchanger (09) for heat recovery before it is returned to the main cooler (07).

10. Method according to claim 8 or 9, characterized in that the heated coolant flowing out of the component cooler (08) is fed into the intercooler (04) and/or the aftercooler (05) via one of a plurality of feed inlets (12), wherein the feed inlet (12) is selected such that an intermediate temperature of the coolant in the intercooler (04) or aftercooler (05) present at the feed inlet (12) corresponds to an outflow temperature of the coolant at the component cooler (08).

Technical Field

The invention relates to a cooling device for at least two-stage compressed air generators. Such a compressed-air generator, also called compressor, comprises: a liquid-cooled intercooler arranged between the first compressor stage and the second compressor stage for cooling the pre-compressed air discharged by the first compressor stage before flowing into the second compressor stage; and an aftercooler cooled with liquid, arranged after the second compressor stage, for cooling the air compressed by the second compressor stage. Furthermore, a liquid-cooled component cooler is provided, which absorbs heat from other components of the compressed-air generator in order to cool, for example, the power electronics or the drive and gear of the compressor stage. The coolant circuit extends through a main cooler, the cold side of which feeds coolant to the respective coolant inlets of the intercooler, aftercooler and component cooler, and the hot side of which receives heated coolant flowing out of the coolant outlets of the intercooler and aftercooler.

The invention further relates to a method for cooling at least two stages of compressed-air generators.

Background

For compressing gaseous media, in particular for generating compressed air, very different embodiments of compressors are known. For example, document DE 60117821T 2 describes a multistage screw compressor having two or more compressor stages, wherein each compressor stage comprises a pair of rotors for compressing a gas. Furthermore, two or more drive means with variable speed are provided, wherein each drive means drives a respective compressor stage.

Document EP 2886862 a1 describes a compressor having a motor, a drive shaft, a crank drive connected to the drive shaft, at least one compressed air generating means, a crank housing and a compressed air reservoir. The cooling of all components takes place by means of a cooling air flow generated by the fan wheel.

DE 102017107602B 3 discloses a compressor installation having an installation housing in which a plurality of heat-generating installation components are arranged. The system includes a twin-screw compressor having two compressor stages for compressing a gaseous medium, in particular for generating compressed air. The device housing furthermore comprises an air-water cooler, a blower generating a cooling air flow, and an air guiding element which supplies air heated by the device components to the air-water cooler.

Document EP 2529116B 1 describes a method for recovering energy when compressing air by a compressor having two or more compression stages. Downstream of the compressor, a heat exchanger having a primary part and a secondary part is provided. Directing compressed gas from a pressure stage through the primary; the coolant is guided through the secondary part.

Document WO 2015/172206 a9 describes a compressor having at least two compression stages in series and at least two coolers, namely an intercooler between the compression stages and an aftercooler downstream after the last compression stage. At least two of the coolers are designed as split coolers, so that the secondary side through which the coolant flows is divided into two stages in order to cool the gas flowing through on the primary side in the hot and cold stages. The two stages of the secondary side are coupled in different cooling circuits. For example, the first stages of the plurality of coolers are connected in series and the second stages are connected in series, respectively.

Document DE 3134844 a1 describes a method for energy-optimizing a compression process, in particular for multi-stage compression mechanisms with centrifugal and piston compressors. For this purpose, the heat pump is integrated into the compressor device. Preferably, at least one evaporator of the heat pump is integrated into a line of the cooling stage which conducts the heated cooling water.

In document US 2018/0258952 a1, a compressor module is described, which comprises a compressor having a housing with an integrated compressor cooler. According to one embodiment, two such modules can be combined with each other such that a low pressure compressor module is connected in series with a high pressure compressor module. Each of the two compressor modules has a liquid-cooled cooler that cools the compressed air at the outlet of the module. Furthermore, a motor cooler and a component cooler are provided, the coolant circuits of which are connected to the coolant circuit of the compressor cooler.

In general, the following requirements always arise for such compressor systems, namely: a greater or lesser amount of heat is removed in order to avoid overheating of the individual components or the overall installation. The overall system has hitherto been cooled regularly by means of cooling air, the heated exhaust gases being discharged to the environment generally without being utilized. The heat is then either lost or only inefficiently recovered from the exhaust gas. Some plants additionally comprise a heat exchanger, the secondary heat transfer medium of which absorbs heat from the primary cooling circuit of the compressor and carries it away. The dissipated heat can then be utilized by an external load.

Disclosure of Invention

Starting from the prior art, the invention has the following tasks: on the one hand, effective cooling of such compressed-air generators (compressor devices) is ensured with a reduced outlay on equipment, but on the other hand, a more effective heat recovery is also provided in relation to the entire compressed-air generator.

This object is achieved by a cooling device for at least two-stage compressed-air generators according to the appended claim 1. Preferred embodiments of the cooling device are listed in the dependent claims 2 to 7. The object is also achieved by a method for cooling at least two stages of compressed-air generators according to the appended claim 8. Advantageous embodiments of the method are listed in the dependent claims 9 and 10.

The cooling device according to the invention is suitable for cooling compressed air generators of the type of a preferred compressor installation, having at least two compressor stages. The cooling device comprises at least one liquid-cooled intercooler arranged between the first compressor stage and the second compressor stage for cooling the pre-compressed air discharged by the first compressor stage before it flows into the second compressor stage. A liquid-cooled aftercooler is arranged after the second or last compressor stage in order to cool the further compressed air. In the simplest case, the compressed air produced is supplied to an external unit after passing through the aftercooler. In a modification, the compressed-air generator can also have more than two compressor stages and accordingly additional intercoolers.

Furthermore, the cooling device comprises a liquid-cooled component cooler which receives heat from other components of the compressed-air generator and discharges it to a coolant. The component cooler is arranged in the housing of the compressed-air generator like other coolers and is configured, for example, as a sheet cooler, a cooling plate, a heat pipe, or the like. The component cooler can be composed of a plurality of individual coolers and serves to dissipate heat, in particular, from the drive of the compressor stage and the power electronics required for controlling the compressed-air generator.

The cooling device has a coolant circuit which includes a main cooler in order to remove heat absorbed by the coolant in the other cooler from the compressed-air generator. The cold side of the main cooler supplies cooled coolant having a low temperature directly to the respective coolant inlets of the intercooler, aftercooler and component cooler. The coolant inlets of the intercooler, the aftercooler, and the component cooler are connected in parallel so as to supply the coolant having the same low temperature thereto. The hot side of the main cooler receives heated coolant directly from the respective coolant inlets of the intercooler (or intercoolers), aftercooler and component coolers, or indirectly from the respective coolant inlets of the intercooler, aftercooler and component coolers when heat exchangers for heat recovery are intermediately connected as described below. The coolant outlets of the intercooler and aftercooler are connected in parallel and the heated coolant having a high temperature is supplied to the main cooler via a heat exchanger if necessary.

It is essential to the invention that the coolant outlet of the component cooler is not connected in parallel with the coolant outlet of the intercooler or aftercooler. This prevents the coolant which is present at the outlet of the intercooler and aftercooler and has a high temperature from being cooled by mixing from the component cooler, since the component cooler regularly provides a lower temperature of the coolant due to less heat to be dissipated. In other words, the coolant of the component cooler is fed to a supply inlet of the intercooler and/or the aftercooler, wherein the supply inlet is arranged between the coolant inlet and the coolant outlet at a location at which an intermediate temperature of the coolant in the intercooler or aftercooler corresponds to an outlet temperature of the coolant at the component cooler ± 20%. Preferably, the temperature of the coolant mixed in by the component cooler differs by less than ± 10%, in particular by less than ± 3%, from the temperature at the mixing point in the intercooler or aftercooler.

The same coolant, preferably water, is thus used for the intercooler, aftercooler and component cooler. As a result, not only the heat from the compressed air that has been compressed, but also the heat from components such as electric motors, frequency converters, compressor stages, gear units, etc., is concentrated in the coolant and carried away by the coolant. The largest part of the waste heat of the entire compressed-air generator is thus used for heat recovery.

Another advantage of the invention is that the main cooler can be made significantly smaller, which leads to a significant reduction in the structural size of the cooling circuit and thus to a significant reduction in the overall cost of the compressed-air generator. Due to the described process of targeted supply of the coolant provided by the component cooler having an intermediate temperature into the intercooler and/or the aftercooler, the high temperatures present at the outlet of the intercooler and the aftercooler can be maintained at a high level, preferably in the range of 90 ℃. This causes a large temperature difference at the main cooler, so that its cooling surface can be kept small compared to when the inlet temperature at the main cooler is low. The necessary cooling surface and the temperature difference between the inlet temperature (high temperature) and the desired outlet temperature (low temperature) are proportional.

According to an advantageous embodiment, the coolant supplied by the component cooler is supplied both to the intercooler and to the aftercooler via the respective supply inlet.

According to a particularly preferred embodiment of the cooling device, the heat exchanger in the cooling circuit is connected between the respective coolant outlets of the intercooler and the aftercooler and the coolant inlet of the main cooler. The entire heat quantity supplied to the coolant is thus used by the heat exchanger for transfer to the heat transfer medium.

Preferably, the main cooler is a water-air-cooler or a water-cooler or a combined cooler with water and air as optional cooling media. The user of the compressed-air generator thus decides whether he achieves the main cooling by means of blower-supported exhaust-gas cooling or by connection to an external liquid cooling medium.

Advantageously, the intercooler and/or the aftercooler have a plurality of supply inlets to which the coolant can be optionally supplied from a coolant outlet of the component cooler. In particular, a distributor unit is arranged between the coolant outlet and the feed inlet of the component cooler, which distributor unit, with temperature control, supplies a feed inlet at which the intermediate temperature of the coolant in the intercooler or aftercooler is closest to the outlet temperature of the coolant at the component cooler.

The intercooler, the aftercooler, the component cooler, the heat exchanger, the first and second compressor stages and the electronic control unit are expediently arranged within a common device housing. The cooling device is thus an integral component of the compressed-air generator, so that the installation effort at the user is limited to a minimum.

The method according to the invention for cooling at least two stages of compressed-air generators comprises the following steps:

-leading the cooling medium in the coolant circuit through a main cooler and through a liquid-cooled first intercooler connected in series with the main cooler, which first intercooler thereby cools the air pre-compressed by the first compressor stage;

-leading the cooling medium in the coolant circuit through an after-cooler, which is also connected in series with the main cooler and in parallel with the intercooler, thereby cooling the air recompressed by the second compressor stage;

-feeding the cooling medium cooled in the main cooler to a liquid-cooled component cooler which absorbs heat from other components of the compressed-air generator;

-feeding the heated cooling medium discharged by the component cooler into the intercooler and/or the aftercooler through a feed inlet, wherein the feeding takes place in the intercooler or aftercooler at a location where the intermediate temperature of the coolant in the intercooler or aftercooler corresponds to the outflow temperature of the coolant at the component cooler ± 20%, preferably both temperatures are substantially the same.

Drawings

Further advantages and details of the invention emerge from the following description of a preferred embodiment with reference to the drawings. Wherein:

FIG. 1 shows a block diagram of a cooling device according to the invention, in which heat recovery is deactivated;

fig. 2 shows a block diagram of the cooling device, in which heat recovery is activated.

Detailed Description

Fig. 1 shows a simplified block diagram of a compressed-air generator 01 or compressor installation. The block diagram firstly includes the main elements of the cooling device and omits the other units of the compressed-air generator. The compressed air generator comprises at least one first compressor stage 02 and one second compressor stage 03. The air pre-compressed in the first compressor stage 01 is supplied to an intercooler 04 at a temperature of, for example, 200 ℃ for cooling and leaves the intercooler at a temperature of approximately 50 ℃ for further compression by the second compressor stage 03. The finally compressed air leaves the second compressor stage 03 at a temperature of approximately 200 ℃ and is then fed to an aftercooler 05 for renewed cooling, so that the compressed air is finally supplied to external units at a temperature of approximately 50 ℃. For heat dissipation, the main cooler 07 is supplied with a cooling medium, preferably cooling water, at a temperature of, for example, 45 ℃ on its cold side. The cooling water is supplied to the inlets of the intercooler 04, the aftercooler 05, and the component cooler 08 in parallel at such a low temperature. The cooling water flows through the intercooler 04 and the aftercooler 05 in order to absorb the heat of the compressed air and is resupplied to the hot side of the main cooler 07 at a high temperature, for example, 90 ℃. In the illustrated embodiment, the cooling water also flows through the heat exchanger 09, but the heat exchanger 09 is deactivated in fig. 1, so that the temperature of the cooling water at the inlet and outlet of the heat exchanger 09 is virtually unchanged. Heat is removed at the main cooler 07 in order to bring the cooling water to a low temperature again. The cooling is effected, for example, with the aid of a blower 11, which delivers heated exhaust gases having a temperature of, for example, 40 ℃.

The cooling device is characterized in that the cooling water is not fed directly to the main cooler 07 or to a preceding heat exchanger 09 in parallel with the cooling water of the intercooler and aftercooler after passing through the component cooler 08. In other words, the cooling water discharge ports of the component coolers are connected to the supply inlets 12 on the intercooler 04 and on the after-cooler 05, respectively. Alternatively, the feed inlet 12 can also be provided only on one of the two coolers 04, 05 and be selected with regard to its position such that there is an intermediate temperature of, for example, 57 ℃ in the coolers 04, 05. The intermediate temperature should substantially correspond to the outlet temperature of the cooling water B provided by the component cooler 08. The cooling water B is thus mixed again into the cooling water a in the intercooler 04 and/or in the aftercooler 05 and is heated there to a high temperature.

Fig. 2 shows a simplified block diagram of the compressed-air generator 01 or compressor installation in the event of a changed operating state, i.e. in the event of heat recovery at the heat exchanger 09 being deactivated. As a result, a temperature drop of the heated cooling water from, for example, 90 ℃ to 50 ℃ occurs at the heat exchanger 09. The heat removed is used for other applications, such as for heating purposes.

List of reference numerals:

01 compressed air generator/compressor installation

02 first compressor stage

03 second compressor stage

04 Intercooler

05 aftercooler

06 –

07 main cooler

08 parts cooler

09 heat exchanger

10 –

11 blower

12 feed inlet