Compressor device with cooling and method for operating a compressor device

Abstract

The invention relates to a compressor device having a compressor for compressing a gas to produce a compressed gas, a cooling device and comprising an oil cooler for cooling oil heated by the compressor, at least one compressed gas cooler, and at least one housing cooler for cooling a housing or a part of a housing of the compressor, the oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each arranged to be cooled by means of a coolant flow consisting of a liquid coolant, in particular water, and wherein at least one housing cooler control is provided for the at least one housing cooler, the compressor device has at least one housing cooler control mechanism for individually controlling the cooling flow through the housing cooler, and has a cooling control device which is configured for actuating the at least one housing cooler control mechanism such that the at least one cooling flow through the at least one housing cooler is controlled independently of the cooling flow through the oil cooler.

Description

Technical Field

[0001] The present invention relates to a compressor device for compressing a gas to produce compressed gas, in particular compressed air, wherein the compressor device has a cooling device. Furthermore, the present invention relates to a method for operating a compressor device having a cooling device. Background Art

[0002] A compressor for compressing a gas to produce compressed gas can also be referred to as a compressed gas compressor. Thus, the compressor is used to produce compressed gas, usually compressed air. The compressed air or other compressed gas is particularly used for subsequent industrial applications. The following elaboration on compressed air also applies to other compressed gases in the same sense.

[0003] Due to the function, heat is generated when producing compressed air. The compressed air and the compressor, especially its housing, are heated and thus must be cooled. For cooling, a housing cooler can be provided to cool the housing of the compressor or a part thereof, and the housing cooler is usually also referred to as or implemented as a jacket cooler. In the case of the housing cooler, a cooling medium (which can also be synonymously referred to as a coolant), especially water, can flow through the housing cooler to cool the housing. In addition, a compressed gas cooler can be provided, which is arranged in a part of the pipeline system that guides compressed gas, especially compressed air. Here, in particular, a heat exchanger can be provided, and a cooling medium or coolant, especially water, also flows through the heat exchanger. Usually, oil is also required when producing compressed gas, especially for lubricating the components of the compressor. This oil is also heated and can be cooled by an oil cooler, which can especially have a heat exchanger. A cooling medium or coolant, especially water, flows through the heat exchanger.

[0004] Efficient cooling can thus be achieved such that all the mentioned coolers (where multiple of the mentioned coolers can also be provided respectively) are connected to a primary cooling circuit. In particular, the cooling can be completely or partially connected in parallel such that as little as possible the already heated water from the previous cooler is obtained by a cooler, which would occur in a series connection.

[0005] By the parallel connection, each cooler obtains its share of cooling water according to the flow resistance of its parallel branch. By correspondingly designing the parallel branch or such a cooler, each cooler obtains an appropriate amount of coolant, i.e., especially water.

[0006] However, it has been proven that the cooling demand and thus the demand for coolant, i.e., cooling water, can fluctuate. To address this, the flow rate of the coolant in the primary circuit can be adjusted accordingly. However, if the coolant demand changes differently in each cooler, over-cooling or under-cooling will occur in other coolers in the case of optimal cooling in a cooler.

[0007] To match this non-optimal cooling, corresponding valves can be provided and adjusted, by means of which the coolant inflow for each cooling can be manually set. However, this adjustment would be time-consuming because the technician has to make or change the corresponding settings for this purpose. The result also depends on the individual capabilities of the technician.

[0008] As a further improvement, individualized cooling can be provided, in which each cooler has its own cooling circuit. However, this solution is costly and thus not necessarily recommended.

[0009] Cooling for a compressor is known from document WO2022163079A1, in which the amount of cooling liquid can be matched in particular. Summary of the Invention

[0010] The object on which the present invention is based is to solve at least one of the foregoing problems. In particular, a solution is to be proposed in which matched cooling for a compressor device with a cooling device is achieved in a simple manner and method. At least one alternative solution is to be proposed for the hitherto known solutions.

[0011] According to the present invention, a compressor device according to an embodiment of the present invention is proposed.

[0012] Therefore, a compressor device is proposed, which has a compressor for compressing a gas to produce compressed gas, in particular compressed air, wherein the compressor has at least one compressor stage, and a cooling device. The cooling device includes an oil cooler for cooling the oil heated by the compressor, at least one compressed gas cooler for cooling the gas that is completely or partially compressed into compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing. The oil cooler, at least one compressed gas cooler, and at least one housing cooler are each arranged to effect cooling by means of a coolant flow composed of a liquid coolant, in particular water.

[0013] For at least one housing cooler, at least one housing cooler control mechanism is provided for individually controlling the cooling flow through the housing cooler. In addition, the compressor device has a cooling control device, which is configured to control at least one housing cooler control mechanism such that at least one cooling flow is controlled through at least one housing cooler independently of the cooling flow through the oil cooler.

[0014] Therefore, a compressor device is provided, which has a compressor and a cooling device. The compressor (which can also be synonymously referred to as a compressed gas compressor) is designed to compress a gas to produce compressed gas. In particular, a compressed air compressor is proposed for producing compressed air. The compressed air compressor produces compressed gas or compressed air in a generally known manner and method.

[0015] Furthermore, a cooling device is provided, which has at least one oil cooler, a compressed gas cooler and a housing cooler. The oil cooler is designed to cool the oil heated by the compressor. For this purpose, the oil can flow through a heat exchanger from the compressor, where the oil outputs its heat to a liquid coolant, especially water, i.e., cooling water.

[0016] The compressed gas cooler (multiple compressed gas coolers can also be provided) is designed to cool the compressed gas. The compressed gas flows through the compressed gas cooler for this purpose and outputs its heat to the liquid coolant here. It is also considered that the compressor has multiple compression stages, such that the gas is placed at a first pressure stage after the first compression stage, which can already be regarded as compressed gas. However, in this regard, the compressed gas has not yet been compressed to the final pressure stage, such that partially compressed gas can be identified. However, for the partially compressed gas (which can also be simply referred to as compressed gas as described) a compressed gas cooler can also be provided, which can be arranged between two compressor stages in this case. If there are at least two compressor stages, a compressed gas cooler can be at least re - arranged after the second compressor stage, which cools the compressed gas output by the mentioned second compressor stage.

[0017] The housing cooler (multiple housing coolers can also be provided) is designed to cool the housing of the compressor or a part of the housing. Here, in principle, the entire physical design of the compressor or its part can be regarded as the housing of the compressor. Therefore, it does not only refer to the housing in the sense of the covering of the compressor, but to the compressor as a physical object. The housing cooler can also include or represent coolant channels in the housing of the compressor stage.

[0018] Therefore, it is proposed for the coolers that the oil cooler, at least one compressed gas cooler and at least one housing cooler are each arranged to achieve cooling by a coolant flow composed of a liquid coolant, especially water. Each of the coolers thus has at least one flow channel through which the coolant can flow. Therefore, the coolers mentioned are subject to the principle of being coolers that are used to cool a coolant flow composed of a liquid coolant, i.e., especially coolers cooled by water or cooling water. Therefore, the coolant flow flows through each cooler during operation.

[0019] For at least one shell cooler, there is provided at least one shell cooler control mechanism for individually controlling the cooling flow through the shell cooler such that it can be individually manipulated. The control of the shell cooler and thus the cooling effect can thereby operate independently of the remaining coolers.

[0020] For this purpose, the compressor device has a cooling control device configured to manipulate at least one shell cooler control mechanism such that at least one cooling flow through at least one shell cooler is controlled independently of the cooling flow through the oil cooler. The cooling control device can thereby be configured such that the cooling control device is implemented as a programmed controller in a corresponding process computer and the process computer is operatively connected to at least one shell cooler control mechanism. The shell cooler control mechanism can be configured as a controllable valve or have such a valve. The shell cooler control mechanism can also include or be a pump, in particular an adjustable pump. The shell cooler control mechanism can be combined with a controllable valve.

[0021] In particular, it is proposed that for each coolant flow there is an individually manipulable control mechanism in order to individually control each coolant flow such that the cooling power can be individually controlled for the oil cooler, at least one compressed gas cooler, and at least one shell cooler respectively. It is also considered here that one of the coolers, for example a compressed gas cooler, has two or more sub-coolers or is divided into two or more sub-coolers, for example into an intercooler and a secondary cooler, and the two sub-coolers can be controlled separately via control mechanisms. Thus, for each of the two or more sub-coolers, its respective coolant flow can be controlled. The sub-coolers are connected in series with one another for this purpose. The individual control of each coolant flow through each of the sub-coolers can be designed such that additionally or only the distribution of the total coolant flow to the sub-coolers is controlled.

[0022] Two shell coolers (which can also be referred to as jacket coolers) can also be connected in series or in parallel. If the shell coolers are connected in parallel, this can be designed such that the coolant flow is distributed to the two shell coolers, and for the two shell coolers there can be provided only one control mechanism in common. However, the individual control of the cooling flow through the shell coolers can thereby also be achieved, since in this case the control is carried out independently of the remaining coolers, in particular independently of the oil cooler.

[0023] Preferably, a primary cooling circuit is provided for all coolers, wherein one or more shell coolers are connected in parallel, fully or partially, with other coolers, in particular with oil coolers. However, this does not exclude that, for example, two coolers, such as two shell coolers (i.e., which can be designed as jacket coolers), are also connected in series. These two serially connected jacket coolers can also be regarded as a common shell cooler.

[0024] Each control mechanism can be configured as a controllable valve, or as a controllable pump, or some control mechanisms are configured as controllable valves while other control mechanisms are configured as controllable pumps. Each control mechanism can be regarded as an individualized control mechanism, which can be individually controlled. Thereby, a continuous adjustment of the coolant flow of each cooler is feasible, so that each cooler can operate at its optimal operating point. Thus, each cooler can be operated optimally. If, for example, there is an increased cooling demand for the oil cooler, its coolant flow can be increased without increasing the coolant flow of the remaining coolers.

[0025] It has been particularly recognized here that the coupling of the hitherto common oil coolers and jacket coolers can be disadvantageous, since different requirements are imposed on the cooling of the housing and the cooling of the oil, so that a decoupling device is proposed.

[0026] It has been recognized here that optimal cooling does not necessarily mean cooling down as much as possible. The housing can expand or contract according to temperature, which can have an impact on its mechanical function, particularly on the size of the gaps between elements moving relative to each other. It is particularly important that at least one gap between the compressor housing and the rotor and / or between the rotors remains within the optimal range. Overcooling of the housing causes shrinkage and thus contact between the rotor and the housing or between the rotors, whereby the gap will increase permanently. When the cooling of the housing is too low, an unnecessarily large gap is generated between the rotor and the housing or between the rotors, which causes an internal reflux of the already compressed gas.

[0027] For the oil cooler, it is important to keep the oil viscosity within the optimal range via the oil temperature. The power consumption increases when the oil is overcooled, and the wear increases when the oil is overheated.

[0028] It is also important to cool the compressed air to the optimal value after the last compressor stage. When the cooling is too low, damage to components may occur or the drying of the compressed air may not function adequately.

[0029] With the proposed solution, low electrical power consumption and an optimal compressed air discharge temperature can be achieved.

[0030] Typically, a high temperature in the total coolant flow or the sum coolant flow is desired. Thus, as much heat as possible should be transferred to the heating water, which can be coupled to the total coolant flow or the sum coolant flow or can use the total coolant flow or the sum coolant flow, for example, to save fuel costs for heating. For this purpose, the temperature level must be correspondingly increased so that the cooling water can be used for heating purposes, which is more likely to be disadvantageous for the cooling of the compressor, yet can be meaningful in the case of corresponding heat demand. By controlling the individual coolers decoupledly, both can be taken into account.

[0031] According to one aspect, it is proposed that the cooling control device is configured to manipulate at least one housing cooler control mechanism such that at least one cooling flow through at least one housing cooler is controlled independently of at least one cooling flow through at least one compressed gas cooler.

[0032] Therefore, additional decoupling means for the housing cooler are provided here. Thereby, the housing cooler can be more specifically adapted to the cooling of the housing and in particular to the optimal clearance width of the clearance between the rotor and the housing.

[0033] According to one aspect, it is proposed that the cooling control device is configured to control the cooling flow only individually for at least one housing cooler, in particular by means of the housing cooler control mechanism, while the cooling flows for the oil cooler and at least one compressed gas cooler are not controlled or are controlled only via a common control of the total coolant flow.

[0034] In particular, it has been recognized here that the targeted manipulation of the housing cooler and thus the precise cooling of the housing are important, while the remaining coolers or the remaining elements to be cooled are insensitive to temperature fluctuations and thus only require cooling with simple control or even work sufficiently without control. It is thus only controlled via the control of the general cooling circuit. Therefore, the construction of the entire cooling system can be kept small while the cooling quality of the housing is high. Fault sources are also avoided by such a simplified cooling circuit.

[0035] In particular, the housing cooling or jacket cooling operates at a lower temperature than the oil cooling. The housing cooling or jacket cooling can operate independently of the oil cooler here.

[0036] According to one aspect, the compressor has at least one rotor for compressing the compressed gas and forms at least one compressor clearance between the housing and at least one rotor or between two rotors, the compressor clearance having a variable clearance thickness, and the cooling control device is configured to manipulate at least one housing cooler control mechanism such that the clearance thickness is kept within a preset range and / or such that the clearance thickness follows a preset desired clearance thickness.

[0037] Therefore, the housing cooling is controlled in a targeted manner such that the compressor clearance, which has been simplified above to be referred to only as clearance, is as optimal as possible. It has been recognized here that the decoupled control via the housing cooler can keep the clearance thickness within a range that is good for the compressor operation.

[0038] The clearance thickness can be detected, or the control can be based on empirical values, which can be recorded in preliminary tests.

[0039] However, since the measurement of the clearance thickness during ongoing operation would be costly, at least one additional sensor would be required, and the clearance thickness can also be controlled via other values. In particular, the clearance thickness can be inferred from the more easily measurable temperature and based on empirical values.

[0040] Cooling for the clearance thickness is important, especially for dry-compression compressors and / or screw compressors. Therefore, it is proposed that the compressor is a dry-compression compressor and / or a screw compressor. A screw compressor is configured to compress gas, especially the air to be compressed, by the movement of two meshing screws with each other. Thus, a continuous compression process can also be particularly performed. A turbo compressor can also be used as the compressor.

[0041] According to one aspect, it is proposed that the cooling control is configured such that the clearance thickness of the compressor is detected and / or estimated and at least one housing cooler control mechanism is controlled according to the detected or estimated clearance thickness.

[0042] Therefore, according to this aspect, in order to control the clearance thickness of the compressor clearance, it is proposed to detect, especially measure and return the clearance thickness. The control device is part of a closed-loop control circuit and can itself also be referred to as a closed-loop control.

[0043] Corresponding sensors can be used for detection. This is more precisely associated with corresponding costs, for which the clearance thickness can be detected with high precision.

[0044] To detect the clearance thickness, it is also considered to determine the clearance thickness with the aid of a state observer. The state observer can use the input temperature of the gas to be compressed flowing into the compressor stage and its volume flow as input variables for this purpose, and use the discharge temperature of the gas at least partially compressed in the compressor stage as an output variable. The clearance thickness is then the state of the state observer, and the comparison between the discharge temperature of the state observer and the detected corresponding discharge temperature can be used to match the state of the state observer or its model. It is also considered to calculate the correlation by model calculation and compare the temperature calculated in this way with the measured temperature, so as to infer the clearance thickness.

[0045] According to one aspect, at least one discharge temperature of a gas that is completely or partially compressed into a compressed gas when discharged from at least one compressor stage is detected, a preset temperature value for the discharge temperature is determined, at which a optimal clearance thickness is expected, wherein the preset temperature value is determined especially during the ongoing operation, and at least one housing cooler control mechanism is controlled such that the discharge temperature follows the preset temperature value, especially adjusting the discharge temperature to the preset temperature value as the desired temperature.

[0046] In particular, it has been recognized here that the temperature of a gas that is completely or partially compressed into a compressed gas when discharged from at least one compressor stage (which is herein referred to as the discharge temperature) allows a rather accurate conclusion regarding the clearance thickness. The correlation between the discharge temperature and the clearance thickness can be recorded in preliminary tests. The preset value can in principle be selected as the value at which an optimal clearance thickness is expected. Thus, if the discharge temperature is adjusted to the preset value, the expected clearance thickness approximately has its optimal value.

[0047] Therefore, it is also proposed to check the housing size or to cool it in such a way that the housing size remains constant. This is especially important for the clearance thickness and can be reduced based on the observation of the clearance thickness. It has been recognized that it is also feasible to indirectly detect the housing size or the clearance thickness via the discharge temperature. In the control device for controlling the cooling, the theoretical discharge temperature is compared with the detected temperature in the case of correct clearances between the rotors and between the rotor and the housing, and the cooling is controlled accordingly. In the case of correct, i.e., optimal, clearance thicknesses between the rotors and between the rotor and the housing, the theoretical discharge temperature can be considered as the preset temperature. Especially for screw compressors, especially in dry-running screw compressors, the clearance thickness should be observed particularly accurately. As far as possible, the clearance thickness should tend towards 0 μm, especially permanently towards 0 μm.

[0048] However, it has also been recognized that the correlation between the optimal clearance thickness and the discharge temperature can be related to other variables, especially to the external temperature and the throughput of the compressed compressed gas. Therefore, according to one aspect, the preset value is determined during the ongoing operation. In particular, it is proposed to determine the preset value based on the coolant temperature and / or the air suction temperature available during the year. Preferably, it is proposed to determine the preset value based on the external temperature and / or based on the throughput of the compressed compressed gas.

[0049] According to one aspect, a compressor device is provided, characterized in that the cooling control device is configured to control at least one shell cooler control mechanism based on at least one coolant temperature. Thereby, the shell cooling can be controlled specifically because, in particular, the coolant temperature can be related to the cooling result by shell cooling. Therefore, it is also possible to start from closed-loop control. Preferably, an expected value is preset for the coolant temperature. Thereby, the coolant can be adjusted to the desired temperature.

[0050] In particular, it is proposed that the cooling control device controls at least one shell cooler control mechanism based on the temperature from the following list:

[0051] - The coolant temperature detected at the coolant outlet of the shell cooler, and

[0052] - The coolant temperature detected downstream of the shell cooler.

[0053] These temperatures best reflect the cooling power of the shell cooler and the shell cooler can best affect these temperatures.

[0054] According to one aspect, a compressor device is provided, which has a compressor for compressing a gas to produce compressed gas, in particular compressed air, and a cooling device. The cooling device includes an oil cooler for cooling the oil heated by the compressor, at least one compressed gas cooler for cooling the gas that is completely or partially compressed into compressed gas, and at least one shell cooler for cooling the housing of the compressor or a part of the housing.

[0055] Furthermore, the oil cooler, at least one compressed gas cooler, and at least one shell cooler are each arranged to achieve cooling through a coolant flow composed of a liquid coolant, in particular water. In addition, at least one shell cooler in the oil cooler and / or the shell cooler is connected in series with at least one compressed gas cooler in the compressed gas cooler, such that the coolant flow successively passes through these serially connected coolers.

[0056] Therefore, a serial connection of at least one part of a plurality of different coolers is provided. In particular, a serial connection of the oil cooler and the compressed gas cooler is proposed. Through the serial connection, it can be achieved that the coolant obtains a high return temperature, so that a higher water discharge temperature in the total coolant flow can be realized. Thereby, the accumulated waste heat can be better utilized. At the same time, the jacket cooling and the oil cooler can also be sufficiently cooled under the condition of a high water inlet temperature.

[0057] In the proposed serial connection, the oil cooler and the shell cooler can still be connected in parallel with each other, so that it is still ensured that the shell cooler can be controlled independently of the oil cooler.

[0058] According to one aspect, the coolant flow through the serially connected coolers first flows through the oil cooler and then through at least one compressed gas cooler, such that the oil cooler is flowed through by coolant at a lower temperature than at least one compressed gas cooler.

[0059] In particular, by this sequence a high discharge temperature can thus be achieved, since the coolant in the compressed gas cooler is also raised to a temperature that cannot be achieved by the oil cooler.

[0060] According to one aspect, a cooling circuit is provided for supplying coolant at the cooling circuit inlet and for retrieving the coolant heated by the cooler at the cooling circuit outlet, in order to cool the heated coolant for recirculation or to supply it to other applications, in particular in order to utilize the heat of the coolant, and the compressor device has a cooling control device. The cooling control device is configured to control the compressor device such that the coolant at the cooling circuit outlet has a temperature of 85 °C to 95 °C, in particular 90 °C to 95 °C.

[0061] For this purpose, a corresponding control program is implemented in the cooling control device, which control program performs corresponding method steps. In addition, such a cooling control device is connected to corresponding control mechanisms of the cooler, in particular valves, such that the control mechanisms can be actuated by the cooling control device. The connection to at least one pump can also be designed to drive the overall cooling flow.

[0062] In order to control the temperature of the coolant at the cooling circuit outlet, the temperature can be measured and fed back, such that the cooling control device can be integrated into a closed-loop control circuit or form a closed-loop control.

[0063] A temperature of 85 °C to 95 °C, in particular 90 °C to 95 °C, can be regarded as a high temperature and other references to high temperatures (also with regard to other aspects) can be specified by temperature values. It has in particular been recognized that a temperature of 95 °C is high, yet still below the temperature of boiling water at atmospheric pressure. Similarly, a limit of 110 °C can be observed, which may be more important since the cooling water in the compressor device is usually under pressure, such that the cooling water evaporates at a higher temperature. It should also be noted that other regulations may apply from 110 °C onwards. The temperatures mentioned are thus designed in particular for cooling water as the coolant.

[0064] According to one aspect, the compressor device is constructed such that the coolant first flows through the oil cooler and then through at least one of the at least one housing cooler.

[0065] Thus, the coolant can first be heated in the oil cooler and then further heated in the housing cooler, in order to thereby achieve a high temperature of the coolant at the cooling circuit outlet.

[0066] The shell cooler can consist of a plurality of shell coolers, and the plurality of shell coolers can be connected in parallel or in series with each other. The further heating of the coolant in the shell cooler can be carried out in two variants and the described effects can be achieved.

[0067] According to one aspect, there are provided a plurality of compressed gas coolers and the compressor device is configured such that the coolant flows through a plurality of compressed gas coolers after flowing through the oil cooler, and the compressed gas coolers are particularly connected in parallel such that the coolant flows through the plurality of compressed gas coolers in parallel.

[0068] Therefore, after the coolant has been heated in the oil cooler, the compressed gas coolers further heat the coolant. By the parallel connection of the compressed gas coolers (which can each be configured as a heat exchanger or can contain a heat exchanger), it can be achieved that the two heat exchangers obtain the same cold water inlet temperature and in counterflow, i.e., in the compressed gas flow (which flows through the corresponding heat exchanger), the compressed air can be cooled to near the water inlet temperature.

[0069] Since the compressed air inlet temperature is typically significantly higher than 100 °C, especially in the range of about 120 °C to 250 °C, the water, i.e., the cooling water, can be heated to the desired temperature by means of two compressed gas coolers if necessary.

[0070] According to one aspect, the compressor device is characterized in that a plurality of compressed gas coolers or the plurality of compressed gas coolers are divided into a plurality of compressed gas cooler groups, wherein the compressed gas coolers in each one compressed gas cooler group are connected in parallel with each other, and the compressed gas cooler groups are connected in series with each other. For this purpose, it can be particularly proposed that the first and second compressed gas coolers are connected in parallel with each other and are connected in series with the third and fourth compressed gas coolers connected in parallel with each other.

[0071] Therefore, it can be achieved that the compressed gas coolers, which are particularly configured as heat exchangers (this can also be designed for all compressed gas coolers in all aspects), obtain coolant with the same water inlet temperature in parallel connection. In counterflow, the compressed gas coolers can cool the compressed air to near the water inlet temperature.

[0072] Here, after the coolant has been heated in the compressed gas coolers of the first compressed gas cooler group, the compressed gas coolers of the subsequent or second compressed gas cooler group further heat the coolant.

[0073] According to the present invention, a method for controlling a compressor device is also proposed, wherein the compressor device has a compressor, in particular a screw compressor, for compressing a gas to produce a compressed gas, in particular compressed air, and wherein the compressor has at least one compressor stage. The compressor device also has a cooling device. The cooling device includes: an oil cooler for cooling the oil heated by the compressor, at least one compressed gas cooler for cooling the gas that is completely or partially compressed into a compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing.

[0074] The oil cooler, at least one compressed gas cooler, and at least one housing cooler are each arranged to effect cooling by means of a coolant flow composed of a liquid coolant, in particular water. For at least one housing cooler, there is provided at least one housing cooler control mechanism for individually controlling the cooling flow through the housing cooler, and the compressor device has a cooling control device. The cooling control device controls at least one housing cooler control mechanism such that at least one cooling flow through at least one housing cooler is controlled independently of the cooling flow through the oil cooler.

[0075] In particular, it is proposed that the method operates as described in connection with the compressor device. Specifically, the method operates as described for the compressor device or the corresponding controller, which is respectively configured to implement the corresponding method or method steps. In particular, the following method or method parts are proposed, the implementation and advantageous effects of which have also been described above in connection with aspects regarding the compressor device.

[0076] According to one aspect, a method is proposed in which the cooling control device controls the cooling flow only for at least one housing cooler, individually, in particular by means of the housing cooler control mechanism, and does not control or only controls the cooling flow for the oil cooler and at least one compressed gas cooler via a common control of the total coolant flow.

[0077] According to one aspect, the compressor has at least one rotor for compressing the compressed gas and at least one compressor gap is formed between the housing and at least one rotor, the compressor gap having a variable gap thickness, and the cooling control device controls at least one housing cooler control mechanism such that the gap thickness is maintained within a preset range and / or such that the gap thickness follows a preset desired gap thickness.

[0078] According to one aspect, the gap thickness of the compressor is detected and / or estimated by using the cooling control device, and at least one housing cooler control mechanism is controlled based on the detected or estimated gap thickness.

[0079] According to one aspect, it is proposed to detect at least one discharge temperature of a gas that is completely or partially compressed into compressed gas when discharged from at least one compressor stage by using a cooling control device; determine a preset temperature value for the discharge temperature, at which an optimal clearance thickness is expected, and in particular, the preset temperature value is determined during the ongoing operation; and control at least one shell cooler control mechanism such that the discharge temperature follows the preset temperature value, in particular, such that the discharge temperature is adjusted to the preset temperature value as the desired temperature. Description of the Drawings

[0080] Hereinafter, the present invention will be described in detail exemplarily with reference to the drawings according to the embodiments.

[0081] Figure 1 A schematic diagram showing a compressor device according to the prior art is shown.

[0082] Figure 2 and Figure 3 Schematic diagrams showing compressor devices according to an embodiment of the present invention are shown respectively.

[0083] Figure 4 A schematic partial cross-sectional view showing a compressor having two compressor stages is shown.

[0084] Figure 5 Shown is Figure 4 An enlarged view of the first compressor stage of the compressor. Detailed Description of the Embodiment

[0085] Figure 1 A compressor device 100 of a compressor 130 having first and second compressor stages 131 or 132 is shown. The compressor 130 and the remaining elements are shown schematically.

[0086] In addition, an intercooler 133 and a secondary cooler 134 are provided. The intercooler and the secondary cooler may also be referred to as a compressed air intercooler or a compressed air secondary cooler. The intercooler is shown here as a part of the compressor 130 because the intercooler is provided between the first and second compressor stages, but the intercooler may also be configured as a separate element. Correspondingly, in another design, the secondary cooler 134, which is not a part of the compressor 130, may be a part of the compressor.

[0087] To cool the first and second compressor stages 131, 132, a first or second jacket cooling device 141 or 142 is provided. The jacket cooling devices 141 and 142 are respectively integrated into the compressor stages 131 or 132.

[0088] Furthermore, an oil cooler 135 is provided. The oil cooler 135 is connected to the oil circulation circuit 145 of the compressor 130. For better overview, the connection between the oil circulation circuit 145 and the compressor 130 is not shown in this figure and also not shown in most of the other figures.

[0089] For cooling the compressor device 100 in general, a primary cooling circulation circuit 150 is provided, which has a coolant inflow section 151 and a coolant return section 152. The mentioned coolers, namely the intercooler 133, the secondary cooler 134, the first and second jacket coolers 141, 142 and the oil cooler 135 are supplied with cold coolant (which is water in the illustrated example) via the primary cooling circulation circuit, that is, via the coolant inflow section 151. The water flow heated by the cooler in this way flows back into the heat sink 154 via the coolant return section 152, and the heat sink is only shown abstractly. The heat sink 154 may but no longer has to be a component of the compressor device 100. A primary heat exchanger 156 is provided in or as the heat sink, and a common coolant flow in the primary cooling circulation circuit 150 can be achieved by the primary coolant pump 158.

[0090] The mentioned coolers, namely the intercooler 133, the secondary cooler 134, the first and second jacket coolers 141, 142 and the oil cooler 135 are connected in parallel in the primary cooling circulation circuit. Thus, all the mentioned coolers are supplied with coolant by the primary cooling circulation circuit 150. The corresponding coolers are connected in parallel to the primary cooling circulation circuit via an intercooler line 163, a secondary cooler branch 164, a jacket cooler branch 166 or an oil cooler branch 165 for this purpose.

[0091] Thus, the jacket cooler line 166 first supplies the first and second jacket coolers 141, 142. In the example according to Figure 1 the first and second jacket coolers 141, 142 are connected in parallel here.

[0092] To set the coolant flow or the ratio between them, manually adjustable valves are provided, namely a manual intercooler valve 173, a manual jacket cooler valve 176 and a manual oil cooler valve 175. To enable the intercooler 133 and the secondary cooler 134 to be better coordinated with each other, a secondary cooler valve 174 is provided.

[0093] Furthermore, a primary regulating valve 159 is provided, and the primary regulating valve can control the return of the total coolant in the coolant return section.

[0094] Furthermore, an oil bypass valve 185 is provided, and the flow of oil through the oil cooler 135 can be controlled by means of the oil bypass valve.

[0095] Thus,Figure 1 A working cooling design is shown, but it has been recognized that there is room for improvement. In particular, it has been confirmed that the individual coolers do not coordinate well with each other at least partially and are cooled with different intensities relative to each other. It has been recognized that there is a need for improvement here in order to achieve good, uniform and thus efficient cooling of the compressor device 100. It has also been recognized that there is a need for cooling that is matched to each cooler, which can also be related to the operating state of the compressor device, in particular its cooling device. In particular, the need for matched cooling can be related to the final pressure, to the rotational speed, to the suction temperature, to the cooling water inlet temperature T10, to the desired cooling water outlet temperature T14 at the temperature measurement site. In particular, the need can be related to the compressed air outlet temperature T100, and to the desired oil temperature T60 or T66.

[0096] It should be noted that the compressor device 100 thus consists of the compressor 130 and the plurality of mentioned coolers together with the primary cooling circuit, and the mentioned coolers including the mentioned primary cooling circuit (optionally an additional secondary cooling circuit) can be understood as the cooling device of the compressor device.

[0097] In particular, the following disadvantages result:

[0098] The distribution of the water volume flow to the parallel coolers has to be set manually, however, the distribution of the thermal power and thus the water temperature can fluctuate significantly depending on the operating point.

[0099] In the case of a relatively high desired outlet temperature at the temperature measurement site, the oil cooler and the jacket cooling device have to be cooled separately with cooling water, which can be done via a secondary cooling system.

[0100] Due to various disturbing variables, there can be significant deviations between the individual outlet temperatures T11, T12, T13, T16.

[0101] In most cases, this results in inefficient use of the cooling water. Damage to the stage due to overcooled cooling water is possible.

[0102] Likewise, the following situation has been determined to be disadvantageous.

[0103] The water outlet temperature has been regulated by the common valve V14.

[0104] The oil temperature has been regulated by a bypass to the oil cooler. The oil cooler receives an unnecessarily large amount of water in most cases, so that the oil cooler can still be sufficiently cooled even under the most adverse conditions.

[0105] The secondary cooler receives an unnecessarily large amount of water in most cases, so that the secondary cooler can still be sufficiently cooled even under the most adverse conditions. Only the temperature T11 = T12 is adjusted via the valve V12 in order to be able to compensate for different thermal powers in the secondary cooler.

[0106] The jacket cooling device receives too little water in most cases in order to be able to reach the desired discharge temperature T14 - however, sometimes it also receives too much and too cold water, which can cause damage to the stage.

[0107] The intercooling device only receives enough water to be able to reach the desired mixed discharge temperature T14.

[0108] If the component temporarily requires better cooling, V14 is opened again so that all heat exchangers receive more water, but the desired water discharge temperature T14 is no longer reached.

[0109] In Figure 1 it can in particular also be seen that the oil cooler 135, the jacket coolers 141 and 142 (which can also be referred to as housing coolers), and the compressed gas cooler, namely the intercooler 133 and the secondary cooler 134, are all connected in parallel to one another. For cooling, this configuration has proven itself, however, the coolers mentioned always receive cold coolant through the parallel connection, and the coolant does not rise to a very high temperature in the respective cooler, so that the temperature at the outlet of the heat exchanger to the primary cooling circuit 150 does not become very high. This temperature can reach, for example, approximately 65 °C as a typical value. Thus, the waste heat cannot be utilized well.

[0110] Figure 2 A compressor device 300 is shown according to one design. The compressor device 300 has a compressor 30 in exactly the same way as the Figure 1 compressor device 100, which has first and second compressor stages 1, 2 with first and second jacket coolers 41, 42. The first and second jacket coolers 41, 42 are connected in series with one another in the illustrated embodiment.

[0111] Furthermore, an intercooler 3 and a secondary cooler 4 are provided, which each cool the compressed gas. The intercooler 3 cools the partially compressed compressed gas here, while the secondary cooler 4 cools the fully compressed compressed gas.

[0112] An oil cooler 5 is also provided, which cools the oil flowing through the compressor 30.

[0113] All the coolers 3, 4, 5, 41 and 42 mentioned are connected to the primary cooling circuit 50, so that the primary cooling circuit supplies coolant to the coolers mentioned. In order to operate the primary cooling circuit - similar to that also in Figure 1Similarly, as shown in [description], there is a primary heat exchanger 10 and a primary coolant pump 12. The primary heat exchanger 10 and / or the primary coolant pump 12 can respectively form part of the compressor device, or may not form part of the compressor device.

[0114] Each of the cooling elements connected to the primary cooling circuit 50 can be controlled non-manually, in particular via a controllable control mechanism, via its own, i.e., individualized control mechanism. For this purpose, regulating valves V11, V12, V13, and V16 are respectively provided, and the regulating valves are respectively arranged in the coolant branches connected in parallel with the primary cooling circuit to control the coolant flow through the corresponding cooling elements. In these embodiments and all other embodiments, the regulating valves can be simply referred to as valves. The first and second jacket coolers 41 and 42 can be controlled via the regulating valve V13. Alternatively, when the first and second jacket coolers 41 and 42 are connected in parallel with each other, a separate valve is also feasible.

[0115] Therefore, the mentioned cooling elements, i.e., the intercooler 3, the secondary cooler 4, the oil cooler 5, and the first and second jacket coolers 41 and 42, can be individually controlled. In particular, the jacket coolers 41 and 42 can be controlled independently of the oil cooler via the valve V13.

[0116] In particular, it is proposed that in order to control the corresponding cooling elements or also in order to control the regulating valves V11 to V13 and V16, the temperature of the coolant, i.e., the cooling water, is also detected and considered. For this purpose, corresponding temperature measurement points T2, T31, T4, and T9 to T16, T19, T20, T29, and T60 are provided. Thus, the cooling can be controlled according to these temperatures.

[0117] In particular, the first and / or second jacket cooling devices can be controlled according to the discharge temperature of the compressed gas when it is discharged from the first and / or second compressor stages 1 or 2, i.e., according to the temperature of the compressed gas detected at the temperature measurement points T2 or T4. The jacket cooling devices 41 or 42 can be controlled jointly via the valve V13, or individually controlled when the jacket cooling devices are connected in parallel with each other. The valve V13, or two corresponding valves in the case of parallel connection, can be referred to as the shell cooler control mechanism. In addition, the shell cooling can be controlled independently of the oil cooler. Thus, a targeted temperature-related control of the jacket cooling devices is feasible. This enables the control of the jacket cooling devices to be targeted at controlling the gap thickness between the rotors or between the rotor and the housing.

[0118] The oil cooler, for its part, can be controlled by the valve V16, independently of the shell cooling device.

[0119] The oil temperature is detected by means of the temperature measuring point T60. Other temperatures can also be detected, such as the discharge temperature T100 as the discharge temperature leaving the compressor unit.

[0120] Preferably, all these temperatures can be incorporated into the control of the cooling and thus into the control of the regulating valves V10 to V13, V16 and V19. However, it is not necessary to take into account all temperatures. Preferably, at least one temperature is considered.

[0121] Thus, according to Figure 2 the compressor unit has a compressed air intercooler 3, a compressed air aftercooler 4, an oil cooler 5 and compressor stages 1, 2 together with jacket cooling devices 41, 42.

[0122] In the present embodiment, there is a cooling water circulation circuit 50 which has a heat exchanger 10, for example for heat recovery. The heat exchanger 10 can be used for waste heat utilization. However, a cooling system which is not used for waste heat utilization can also be used. However, in combination with waste heat utilization, the utilization is particularly large.

[0123] Supplementally, there is a secondary cooling circulation circuit 580 which is designed to cool the total coolant flow of the primary cooling circulation circuit 50. For this purpose, there is a connection via a primary-secondary heat exchanger 9.

[0124] The secondary cooling circulation circuit 580 can output heat again via a secondary heat exchanger 11 and its coolant flow can be driven by a secondary coolant pump 13.

[0125] The secondary cooling circulation circuit 580 can cool the coolant flow of the primary cooling circulation circuit, in particular the total coolant flow, and for this purpose there is a primary-secondary heat exchanger 9. For the control, there is also a regulating valve V10, and thus the regulating valve is arranged in the coolant branch of the primary-secondary heat exchanger 9. The control of the regulating valve V10 can be carried out according to the follow-up temperature of the coolant leaving the primary-secondary heat exchanger 9. For this purpose, there is a temperature measuring point T10. The temperature of the coolant flowing through the regulating valve V10 can be detected at the temperature measuring point T24.

[0126] When the water inlet temperature T9 to the compressor is too high so that the heat exchanger cannot cool the compressor, such as the oil, sufficiently, the heat exchanger 9 is used. Then, the incoming water can be cooled to a desired, sufficiently low temperature T10 via the heat exchanger 9.

[0127] A similar situation results when less heat or no heat is required in the primary heat exchanger 10, and then a temperature T9 which is approximately the temperature T14 can be achieved. Because the lower the temperature T31, the lower the power consumption of the compressor and when the temperature T13 (see Figure 2)is sufficient or even optimally low, causing the temperature T10 to be kept as low as possible in the case of low heat demand.

[0128] The heat exchanger 9 is specifically proposed for the case where the water inlet temperature T9 at the temperature measurement site in the compressor is too high, such that the heat exchanger cannot sufficiently cool the compressor, such as the oil. Thus, the incoming water can be cooled to a desired, sufficiently low temperature T10 via the heat exchanger 9.

[0129] A similar situation results when less heat or no heat is required in the heat exchanger 10, and the temperature at T9 approximately reaches the temperature at T14. Because the lower the temperature at T31, the lower the power consumption of the compressor and when the temperature at T13 is sufficient / optimally low, causing the temperature at T10 to be kept as low as possible in the case of low heat demand.

[0130] Via the four regulating valves V11, V12, V13 and V16, the water volume flow through the components 3, 4, 5, 1, 2 or 41, 42 can be set individually and optimally.

[0131] Closed-loop control of the (mixed) water discharge temperature T14 of the compressor is feasible via the above valves V11, V12, V13, V16.

[0132] Specifically proposed is to include the temperatures at the measurement sites T11 and T12 according to the drawing, after the first and second compressor stages, in order to exclude bubble formation and thus the associated risks.

[0133] Proposed here is to include, for example, at least one oil temperature at the measurement site T60 in the control in order to regulate the water volume flow via the oil cooler. Alternatively, component temperatures, such as the bearing outer ring temperature, can be used.

[0134] Specifically preferably proposed is to include the inlet temperature of the compressed gas into the second compressor stage, thus especially the temperature at the measurement site T31, in the control in order to protect the second compressor stage from overheating and in particular to improve efficiency.

[0135] By means of Figure 2 the construction can also achieve a high temperature of the coolant at the outlet of the cooling circuit, namely at the discharge section to the heat exchanger 10 and thus at the temperature measurement site T14. Temperatures of 85 °C to 95 °C, especially 90 °C to 95 °C, can be achieved. This can be realized by the series connection of the first and second compressed gas coolers 3 and 4 with the jacket coolers 41, 42 and the oil cooler 5. The first and second compressed gas coolers 3 and 4 thereby obtain a coolant with a temperature increased relative to the temperature T10, such that the first and second compressed gas coolers can further heat such already preheated coolant.

[0136] Overall, a higher temperature of the coolant can thus be achieved. Thereby, the waste heat in the coolant can be better utilized.

[0137] Figure 2 An embodiment of [the invention] provides a primary - bypass - regulating valve V19, which can also be simply referred to as the bypass valve V19 for short, and a part of the total coolant flow of the primary cooling circuit 50 can be conveyed to the intercooler 3 and the secondary cooler 4 via the first and second jacket coolers 1, 2 and the oil cooler 5 before the tapping point - also after the tapping point according to one embodiment. Here, in particular, a series connection of the oil cooler 5 and the first and second jacket coolers 41, 42 with these two compressed - gas coolers, namely the intercooler 3 and the secondary cooler 4, is provided. Thus, these two compressed - gas coolers receive the coolant heated by the oil cooler 5 and the first and second jacket coolers 41, 42. However, via the valve V19, a still cooler coolant, i.e., a coolant that has not yet passed through the oil cooler 5 and the first and second jacket coolers 41, 42, can be conveyed to these two compressed - gas coolers, whereby the volume flow to the oil cooler can be reduced. This can be particularly used during cold start, as will be further elaborated below.

[0138] The series connection of the oil cooler 5 and the first and second jacket coolers 41, 42 with these two compressed - gas coolers, namely the intercooler 3 and the secondary cooler 4, is proposed as an optimized routing for waste - heat utilization at a high temperature level. The oil cooler 5 and the jacket coolers 41, 42 hereby receive the maximum volume flow of the primary water that has not yet been pre - heated, and the primary water still has the temperature T10.

[0139] The primary - bypass - regulating valve V19 is particularly used during cold start. When the oil has not yet reached the operating temperature, the primary - bypass - regulating valve V19 is opened. When the coolant is still cold, i.e., when there is particularly cold cooling water at the temperature measurement points T10, T13, T15, the regulating valve V13 can also be closed. However, it has been recognized that the valves V11 and V12 should control a sufficient water flow very quickly after cold start. Therefore, it is proposed to open the valve V19 during cold start. During operation, when the cold - start process is over, it is proposed that the bypass valve V19 is slightly closed again, so that the oil cooler and the jacket coolers can receive a relatively high volume flow of cooling water.

[0140] The preset water discharge temperature at the measurement point T14, i.e., the desired temperature, can be obtained only from the mixing of the sub - coolant flows with the temperatures T11 and T12. In these two coolers, a higher discharge temperature can be achieved. In particular, a high discharge temperature T14 can be achieved thereby.

[0141] It has been recognized that the following advantages are obtained.

[0142] It is possible to provide waste heat from the oil cooler and the jacket cooling for waste heat utilization, even at water temperatures, i.e., coolant temperatures, which have hitherto been impossible.

[0143] Higher desired temperatures for the discharge temperature T14 can be achieved because only the sub-coolants with temperatures T11 and T12 or at the measuring points T11 and T12 are mixed, resulting in a mixing temperature that is not mixed downwards by the coolant with temperatures T16 and T15. Temperatures of 85 °C to 95 °C, in particular 90 °C to 95 °C, can be achieved as the discharge temperature T14 of the coolant in the primary cooling circuit.

[0144] Thus, high temperatures can be achieved with a water system and at the same time high power can be achieved, for which a hot water system would otherwise be required.

[0145] Below, some of the main aspects of the embodiments according to Figure 2 are summarized.

[0146] There are two cooling water circuits 50, 5800.

[0147] The coolers 3, 4, 5 and the jacket cooling of stages 1, 2 are located in the primary circuit 50. Here, there is first a parallel connection of the oil cooler 5 and the jacket cooling devices of stages 1, 2. Subsequently, the intercooler 3 and the secondary cooler 4 are connected in series. The intercooler and the secondary cooler are also connected in parallel with each other.

[0148] The secondary circuit 580 cools the primary circuit 50 as required here.

[0149] The wiring variants offer particular advantages in terms of heat recovery via the heat exchanger 10, which can also be referred to as waste heat utilization.

[0150] The following advantages result.

[0151] Higher heat recovery power is feasible and, if necessary, less cooling water demand / no cooling water demand.

[0152] Closed-loop control to a higher water discharge temperature T14 is possible, i.e., the possibility of presetting a higher desired value for the water discharge temperature T14, i.e., the possibility of presetting a higher value for the water discharge temperature T14, i.e., higher than the hitherto desired value (e.g., 90 °C,..., 95 °C, instead of ~80 °C or 85 °C as hitherto).

[0153] The following additional advantages result.

[0154] It is possible to optimally close-loop control the mixed water discharge temperature T14 by using individual volume flow closed-loop control for each heat source.

[0155] The user can preset the water discharge temperature T14.

[0156] The oil cooler always only receives as much water as needed in order to achieve an optimal oil temperature. The following Figure 3 describes another embodiment, however, for the sake of a particular overview, partially identical reference numerals are used for Figure 2 the embodiments in order to better show the correlation. However, for this purpose it is not necessary that these elements are actually identical.

[0157] Figure 3 An embodiment of a compressor device 300 is shown, which is provided with a jacket cooler heat exchanger 6 for the first and second jacket coolers 41, 42. The jacket coolers 41, 42 can also be connected in series here. The coolant flow through the jacket coolers 41, 42 is driven by a jacket cooler pump 14, thus driving its own cooling circuit, which can be referred to as the compressor cooling circuit 32, since the coolant flows through the corresponding jacket areas in the first or second compressor 1, 2. Thus, the jacket cooler pump 14 is a coolant pump for the compressor cooling circuit 32. The compressor cooling circuit 32 or the coolant therein flows through the first and second jacket coolers 41, 42 and is guided through the heat exchanger 6, i.e., through the primary side of the jacket cooler heat exchanger 6. Through the secondary side of the jacket cooler heat exchanger 6, the coolant flows out of the primary cooling circuit 50. The corresponding coolant flow from the primary cooling circuit 50 through the jacket cooler heat exchanger 6 is controlled by an adjustment valve V13.

[0158] As relevant temperatures, the temperatures at the temperature measurement locations T9, T10, T11, T12, T14, T16, T19, T20, T23, T24, T28, T29, T31, T51, T52, T85, T100 are recorded. Additionally, the pressure dew point M85 after the adsorption dryer 20 can also be recorded.

[0159] Preferably, the valve V13 is controlled according to the temperature of the coolant leaving the first and / or second jacket coolers 41, 42.

[0160] The temperature at the measurement location Txx with the placeholder "xx" as the corresponding number for the temperature or measurement location can also be simply and synonymously referred to as temperature Txx hereinafter and above.

[0161] During cold start, V13 remains closed, such that there is no coolant flow at T23 subsequently. Therefore, no elevated temperature is obtained at the temperature measurement site T23 either. When the temperature of the coolant leaving the first and / or second jacket coolers 41, 42 increases, the valve V13 is opened by the controller, which can also be referred to as "regulated to open". The temperature at the measurement site T23 can only be used for closed-loop control.

[0162] The regulating valve V13 can be referred to as a jacket cooler regulating valve and the regulating valve controls the coolant flow through the jacket cooler heat exchanger 6. In other design variants, the volumetric flow of the coolant for the jacket coolers 41, 42 can also be controlled. The valve V13 controls the temperature of the coolant leaving the first and / or second jacket coolers 41, 42.

[0163] Figure 3 There are also a second and a third secondary cooler 7, 8, which can also be referred to as a second and a third compressed air secondary cooler and are specifically configured as heat exchangers here. The second and third secondary coolers are arranged in the compressed gas line 34, i.e., downstream of the compressed gas and after the secondary cooler 4 or the compressed air secondary cooler 4. Thereby, additional cooling of the compressed gas can be achieved. The third compressed air secondary cooler or the compressed air secondary cooler can also be synonymously referred to as a dryer secondary cooler.

[0164] Particularly preferably, this also shows Figure 3 an embodiment in which a dryer is used for compressing the gas, in particular an adsorption dryer 20, which is integrated into the compressed gas line 34. In a refrigerated dryer, an additional secondary cooler 7 is also meaningful in order to regulate the dew point and the discharge temperature thereby. However, the third compressed air secondary cooler 8 has less meaning in the refrigerated dryer 8 as shown. In a refrigerated dryer, the third compressed air secondary cooler 8 is more likely used for heating the compressed air. Therefore, the use of an adsorption dryer is specifically proposed here. In an adsorption dryer, the third compressed air secondary cooler 8 is specifically used for cooling the compressed air.

[0165] It is specifically proposed here that the compressed air dryer 20 is arranged in the flow direction of the compressed gas behind the second secondary cooler 7 and in front of the third secondary cooler 8.

[0166] In order to control the coolant flow through the second secondary cooler 7 and the third secondary cooler 8, regulating valves V25 or V28 are provided respectively. Thus, even the second and third secondary coolers 7, 8 can be controlled independently of each other.

[0167] Additionally, temperature measurement locations T25 or T28 are respectively provided and are associated with the second or third secondary coolers 7, 8 and thus with the corresponding regulating valves V25 or V28.

[0168] It has been recognized in particular here that the dryer can be supported by means of the second secondary cooler 7, so that the pressure dew point after the dryer can be influenced. However, the discharge temperature leaving the dryer also decreases as a result, which is sometimes desirable, but sometimes not.

[0169] By means of a heat exchanger, i.e., the secondary cooler after the dryer, the compressed air can be brought to an optimal temperature for downstream applications. In an adsorption dryer, the air at the outlet can be significantly hotter than the air at the inlet, such that cooling may be required again here.

[0170] The regulating valve V25 that controls the coolant flow through the second secondary cooler 7 can control the coolant flow based on the temperature detected by the temperature measurement location T25. However, preferably, the air discharge temperature T52 is regulated by means of the valve V25. The desired value for the temperature T52 is derived from the desired pressure dew point after the dryer by means of a regulating cascade in a facility having a dryer. In a facility without a dryer, the desired value for the temperature T52 can be derived from the desired value for the temperature T100 that can be preset externally.

[0171] According to another design, closed-loop control based on the temperature T25 or based on the temperature difference T25 to T20 is also feasible.

[0172] Therefore, the regulating valve V25 controls the coolant flow based on the discharge temperature of the compressed air leaving the second secondary cooler 7 at the temperature measurement location T52.

[0173] It is also proposed that the regulating valve V28 that controls the coolant flow through the third secondary cooler 8 regulates the compressed air discharge temperature T100. According to an alternative design, closed-loop control based on the temperature T28 or the temperature difference T28 to T20 is proposed.

[0174] Therefore, this can be done based on the temperature of the temperature measurement location T28, i.e., it is feasible to control the coolant flow based on the coolant temperature at the output of the third secondary cooler 8.

[0175] In the illustrated embodiment, it is additionally proposed that the secondary cooling circuit 580 cools the coolant flow of the primary cooling circuit 50, in particular the total coolant flow, and for this purpose a corresponding primary-secondary heat exchanger 9 is provided. For the purpose of control, a regulating valve V10 is also provided, which is therefore arranged in the coolant branch and thus also in the coolant flow, i.e. in the secondary cooling circuit of the primary-secondary heat exchanger 9. The control of the regulating valve V10 can be carried out according to the tracking temperature of the coolant leaving the primary-secondary heat exchanger 9. For this purpose, a temperature measuring site T10 is provided. The temperature of the coolant flowing through the regulating valve V10 can be detected at the temperature measuring site T24.

[0176] It is proposed here that in Figure 3 the embodiment shown according to Figure 2 the primary coolant pump 12 is split, i.e. instead thereof two primary coolant pumps 12a and 12b are provided, i.e. one primary coolant pump before the primary-secondary heat exchanger 9 and the other primary coolant pump after the primary-secondary heat exchanger 9. In addition, a primary circuit bypass 21 can be provided, through which a part of the total coolant flow of the primary cooling circuit 50 flows around the primary heat exchanger 10. By means of the internal pump 12b, the operation of the compressor and thus the compressed air supply can be maintained in interaction with the bypass 21 and the heat exchanger 9, even if no external heat sink 10 and / or pump 12a is provided. This may be the case, for example, during maintenance work or conversion measures or also in the case of seasonal heat demand.

[0177] The external pump 12a is designed in particular for external pressure losses, i.e. the pressure losses in the heat exchanger 10, in the pipelines and, if necessary, in other components. The internal pump 12b can be operated together for assistance or can also only be ready for use in case of need. The internal pump is switched on only when the primary coolant pump 12a does not supply water or supplies too little water and otherwise the compressor would overheat and cause a shutdown.

[0178] In addition, a pressure dew point temperature measuring site M85 is provided after the drying device 20. Therefore, the pressure dew point temperature is determined at this site and the cooling can be controlled accordingly. In particular, it is proposed to control the second secondary cooler 7 and / or the valve V25 according to the pressure dew point temperature.

[0179] When an additional secondary cooler 7 is present, the valve V25 has a great effect in this case.

[0180] In addition, the dew point M85 can be improved by the valve V11 (opened less to increase the temperature T31) and the valve V12 (opened more to lower the temperature T51).

[0181] A higher regeneration temperature for the dryer is obtained through the higher temperature T31, enabling a lower dew point M85 to be achieved.

[0182] It has been recognized that the valve V25 has the greatest effect as long as the additional secondary cooler 7 is present. In addition, the dew point M85 can be improved by the valve V11 (by opening the valve V11 less to increase the temperature T31) and the valve 12 (by opening it wider to decrease the temperature T51).

[0183] It has also been recognized that a higher regeneration temperature for the dryer, particularly the adsorption dryer 20, can be achieved through the higher temperature T31, enabling a lower dew point M85 to be achieved.

[0184] In particular, the pressure dew point after the dryer is important. At the inlet of the dryer, in most cases the compressed air is saturated to 100%. Therefore, here the temperature and the pressure dew point are nearly the same, provided that the condensed matter that has fallen is separated and discharged as completely as possible before the dryer.

[0185] For the drying result, in particular the temperature of the compressed gas at the inlet where it enters the dryer is important.

[0186] If the condensed matter is not separated before the dryer, the drying result will become slightly worse. However, the compressor should be designed such that the condensed matter that has already fallen has been separated beforehand.

[0187] The condensate separator and the condensate discharger are not shown in the illustration partly for reasons of simplification.

[0188] According to Figure 3 the embodiment is designed such that the second secondary cooler 7 and the third secondary cooler 8 are connected in parallel to the primary cooling circuit 50. A secondary cooling circuit 580 is also provided, which is designed as in Figure 2 and is coupled to the primary cooling circuit 50.

[0189] The intercooler 3 and the secondary cooler 4 (which can also be synonymously referred to as the first secondary cooler 4 in this embodiment and the remaining embodiments) are not connected to the primary cooling circuit 50 in a parallel connection as in Figure 2 the embodiment, but in a series connection, in which the coolant from the primary cooling circuit 50 is fed to the intercooler and the secondary cooler after it has flowed through the remaining coolers. The primary-bypass-adjusting valve V19, as in Figure 2As shown here, this is optional because there is always sufficient water volume flowing through, in particular, the second secondary cooler 7 together with the regulating valve V25, such that the intercooler 3 and the secondary cooler 4 connected in series downstream always receive sufficient volume flow. However, this is prophylactically marked as a possible alternative. The primary-bypass-regulating valve V19 can be used in the case where valve V28 is closed because the temperature T100 is low enough and valve V25 is closed because the pressure dew point M85 is low enough. Subsequently, valve 19 must be opened so that, in particular, the heat exchanger 3 receives more and colder water after the compressor or compressor stage 1, since the compression efficiency is thereby improved.

[0190] The described embodiment with the primary-bypass-regulating valve V19 and the heat exchanger control valve V25 can still be implemented. The embodiment can be meaningful in special cases when warmer compressed air is required in winter. Then, valves V28 and V25 must be closed for the secondary cooler so that without having to open the primary-bypass-valve V19, not enough water can be delivered to the intercooler or the secondary cooler.

[0191] By means of the primary-bypass-regulating valve V19, it is possible to deliver a part of the coolant to the intercooler 3 and the secondary cooler 4, which part does not flow through the third secondary cooler 8. It is thus also proposed that the intercooler 3 and the secondary cooler 4 are arranged or connected in series in the primary cooling circuit, but are connected in parallel with each other. By means of this series connection, a higher cooling water temperature can be achieved by the intercooler 3 and the secondary cooler 4, in particular at the output of the primary cooling circuit 50, where the discharge temperature of the cooling water at T14 can be particularly high.

[0192] For Figure 2 and Figure 3 the following should be noted for the embodiments. In both of these embodiments, the intercooler 3 and the secondary cooler 4 are connected in series with the primary cooling circuit, where, for the sake of simplicity, the primary-bypass-regulating valve V19 is ignored for the following explanations. Thus, the intercooler 3 and the secondary cooler 4 jointly receive the complete coolant flow of the primary cooling circuit 50, i.e., the total coolant flow, which has flowed through the cooler and has thus been heated relative to the temperature T10, since this is affected by the series connection. Thereby, the intercooler 3 and the secondary cooler 4 can output coolant with a relatively high temperature.

[0193] For Figure 3 the embodiment and other embodiments, the following advantages result:

[0194] The maximum heat recovery is feasible with sufficient heat losses and operation without cooling water. Thus, it is considered unnecessary to use the secondary cooling system 11. However, the secondary cooling system can be ready for cases where less heat is required or better cooling of the compressor is needed.

[0195] As an application, a connected building heating system is proposed for this purpose. The building heating system can have the following functions. In winter, all heat can be utilized via the heat exchanger 10. While in summer, less heat is required, yet nevertheless the heat still has to be removed. This is then carried out via the primary-secondary heat exchanger 9, the secondary cooling system 11, and the valve 10.

[0196] Depending on the temperature requirements and alternatives, about 10%, …, 30% more waste heat utilization can be feasible. The maximum waste heat utilization is feasible when the water inlet temperature is about 5 K, …, 10 K higher.

[0197] A very high water discharge temperature T14 is feasible, especially up to about ~95 °C.

[0198] In the case of a high volume flow, sufficient jacket cooling and oil cooling can be carried out with heated water, especially via the primary water system with an inflow or outflow temperature T10 or T14.

[0199] Sufficient dew points can be achieved because the secondary cooler 7 receives a large volume flow of cold heated water.

[0200] When needed, a low compressed air discharge temperature is feasible because the secondary cooler 8 receives cold heated water.

[0201] To control the compressor cooling circuit 32 (which can also be called the jacket cooling circuit), a control valve V13 and a jacket cooler pump 14 are provided. The control valve and the jacket cooler pump form a possible variant for the jacket cooling circuit.

[0202] Furthermore, in Figure 3 the temperatures T2 and T4 are marked. Both can take, for example, 180 °C. It should be noted that in this way, high water discharge temperatures T11, T12, and T14 of, for example, 90 °C can be easily achieved, which is not feasible with the temperatures T16 and T23 shown in Figure 1

[0203] Figure 4 A schematic partial sectional view of a compressor 900 having a first and a second compressor stage 901 or 907 is shown. For this purpose, Figure 5 an enlarged view of the first compressor stage 901 is shown. Below, with reference to Figure 4 , as long as the first compressor stage is explained, additional reference is made to Figure 5 . ​

[0204] Thus, Figure 4 a dry-running screw compressor is shown, which basically forms the compressor 900. Thus, the first compressor stage 901 performs the compression of the first stage during operation. For this purpose, the first compressor stage 901 has a housing 902 and a jacket-cooled coolant channel 903, which is shown more clearly in Figure 5 this regard.

[0205] In order to compress the compressed gas, in particular compressed air, there is provided a compressor screw 904, which engages with each other for compression. The compressor screw is driven via the drive shaft 905 of the corresponding compressor stage. The second compressor stage 907, which further compresses the gas, in particular the compressed air, compressed in the first compressor stage, has a housing 909 with a coolant channel 908 and a compressor screw 910, which is driven via the drive shaft 911.

[0206] The two drive shafts 905 and 911 are driven via a common drive motor 906, and for this purpose a transmission 912 is provided, which distributes the drive power from the drive motor to the two drive shafts 905 and 911 in order to drive the compressor screws 904 and 910 thereby.

[0207] The two compressor stages 901 and 907 can be cooled via jacket cooling achieved by means of the coolant channels 903 and 908. For this purpose, a cooling medium, in particular cooling water, flows through the coolant channels 903 and 908, and the cooling medium can be controlled jointly or individually.

Claims

1. A compressor device, comprising: a compressor, in particular a dry-compression screw compressor, for compressing a gas to produce compressed gas, in particular compressed air, wherein the compressor has at least one compressor stage, and - a cooling device and the cooling device comprises: - an oil cooler for cooling the oil heated by the compressor, - at least one compressed gas cooler for cooling the gas which is fully or partially compressed into the compressed gas, and at least one casing cooler for cooling the casing or a part of the casing of the compressor, wherein The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each designed to be cooled by a coolant flow consisting of a liquid coolant, in particular water, and wherein at least one housing cooler control device is provided for the at least one housing cooler for individually controlling the cooling flow through the housing cooler, and The compressor arrangement has a cooling control device, and the cooling control device is configured to actuate the at least one casing cooler control device in such a way that at least one cooling flow through the at least one casing cooler is controlled independently of a cooling flow through the oil cooler.

2. The compressor device according to claim 1, It is characterized in that The cooling control device is configured to control the at least one casing cooler control mechanism in such a way that the at least one cooling flow through the at least one casing cooler is controlled independently of the at least one cooling flow through the at least one compressed gas cooler.

3. The compressor device according to claim 1 or 2, It is characterized in that The cooling control device is configured to control the cooling flow only individually for the at least one casing cooler, in particular by means of a casing cooler control, and not to control the cooling flow for the oil cooler and the at least one compressed gas cooler, or to control the cooling flow only via a common control device for the total coolant flow.

4. A compressor device according to any one of claims 1 to 3, It is characterized in that the compressor has at least one rotor for compressing the compressed gas and at least one compressor gap is formed between the housing and the at least one rotor or between two rotors, the compressor gap having a variable gap thickness, and The cooling control device is configured to control the at least one housing cooler control mechanism such that the gap thickness remains within a predeterminable range and / or such that the gap thickness follows a predeterminable desired gap thickness.

5. The compressor device according to any one of claims 1 to 4, It is characterized in that The cooling control device is configured to: - detecting and / or estimating a gap thickness of the compressor or said gap thickness, and - controlling the at least one casing cooler control mechanism as a function of the detected or estimated gap thickness.

6. A compressor device according to any one of claims 1 to 5, It is characterized in that The cooling control device is configured to: - detecting at least one discharge temperature of the gas fully or partially compressed to form the compressed gas when it is discharged from the at least one compressor stage; - determining a predefined temperature value for the discharge temperature, at which an optimum gap thickness is to be expected, wherein the predefined temperature value is determined in particular during ongoing operation; and - controlling the at least one housing cooler control mechanism such that the discharge temperature follows the preset temperature value, in particular such that the discharge temperature is adjusted to the preset temperature value as a desired temperature.

7. A compressor device according to any one of claims 1 to 6, It is characterized in that The cooling control device is configured to: - controlling the at least one housing cooler control device as a function of at least one coolant temperature, in particular -Control according to the temperature in the table below - a coolant temperature detected at the coolant output of said housing cooler, and - A coolant temperature detected downstream of said casing cooler.

8. A compressor device, in particular a compressor device according to any one of the preceding claims, comprising: - a compressor for compressing a gas to produce compressed gas, in particular compressed air, and - a cooling device and the cooling device comprises: - an oil cooler for cooling the oil heated by the compressor, - at least one compressed gas cooler for cooling the gas fully or partially compressed into the compressed gas, and at least one casing cooler for cooling the casing or a part of the casing of the compressor, wherein The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each arranged to be cooled by a coolant flow consisting of a liquid coolant, in particular water, and wherein The oil cooler and / or at least one of the at least one housing cooler is connected in series with at least one of the at least one compressed gas cooler, so that the coolant flow flows successively through these series-connected coolers.

9. The compressor device according to claim 8, It is characterized in that The compressor device is configured such that - the coolant flow through the series-connected coolers first flows through the oil cooler, and The at least one compressed gas cooler is then flowed through, so that the oil cooler is flowed through with coolant having a lower temperature than the at least one compressed gas cooler.

10. The compressor device according to claim 8 or 9, It is characterized in that a cooling circuit is provided for providing the coolant at an inlet of the cooling circuit and for recovering the coolant heated by the cooler at an outlet of the cooling circuit in order to cool the heated coolant again or to supply it to other uses, in particular in order to utilize the heat of the coolant, and The compressor device has a cooling control device, which is configured to control the compressor device so that The coolant at the cooling circuit outlet has a temperature of 85°C to 95°C, in particular 90°C to 95°C.

11. A compressor device according to any one of claims 8 to 10, It is characterized in that - a plurality of compressed gas coolers are provided, and The compressor arrangement is designed in such a way that the coolant, after it has flowed through the oil cooler, flows through a plurality of compressed gas coolers, which are in particular connected in parallel so that the coolant flows through them in parallel.

12. A compressor device according to any one of claims 8 to 11, It is characterized in that - a plurality of compressed gas coolers or the plurality of compressed gas coolers is divided into a plurality of compressed gas cooler groups, wherein The compressed gas coolers in each compressed gas cooler group are connected in parallel with one another, and - The compressed gas cooler groups are connected in series with one another, wherein in particular - the first compressed gas cooler and the second compressed gas cooler are connected in parallel with each other, and - connected in series with a third compressed gas cooler and a fourth compressed gas cooler connected in parallel to each other.

13. A method for controlling a compressor device, the compressor device comprises a compressor, in particular a screw compressor, for compressing a gas to produce compressed gas, in particular compressed air, wherein the compressor comprises at least one compressor stage, and - having a cooling device and the cooling device comprising: - an oil cooler for cooling the oil heated by the compressor, - at least one compressed gas cooler for cooling the gas fully or partially compressed into the compressed gas, and at least one casing cooler for cooling the casing or a part of the casing of the compressor, wherein The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each designed to be cooled by a coolant flow consisting of a liquid coolant, in particular water, and wherein at least one housing cooler control device is provided for the at least one housing cooler for individually controlling the cooling flow through the housing cooler, and The compressor device has a cooling control device, and the cooling control device activates the at least one casing cooler control device in such a way that at least one cooling flow through the at least one casing cooler is controlled independently of the cooling flow through the oil cooler.

14. The method according to claim 13, It is characterized in that Use of a compressor device according to any one of claims 1 to 12.

15. The method according to claim 13 or 14, It is characterized in that The cooling control controls the cooling flow only individually for the at least one casing cooler, in particular by means of the casing cooler control, and does not control or controls the cooling flow for the oil cooler and the at least one compressed gas cooler only via a common control of the overall coolant flow.

16. The method according to any one of claims 13 to 15, It is characterized in that the compressor has at least one rotor for compressing the compressed gas and at least one compressor gap is formed between the housing and the at least one rotor, the at least one compressor gap having a variable gap thickness, and The cooling control device controls the at least one housing cooler control device in such a way that the gap thickness remains within a predeterminable range and / or the gap thickness follows a predeterminable desired gap thickness.

17. The method according to any one of claims 13 to 16, It is characterized in that By using the cooling control device - detecting and / or estimating a gap thickness of the compressor or said gap thickness, and - controlling the at least one casing cooler control mechanism as a function of the detected or estimated gap thickness.

18. The method according to any one of claims 13 to 17, It is characterized in that By using the cooling control device - detecting at least one discharge temperature of the gas fully or partially compressed to form the compressed gas when it is discharged from the at least one compressor stage; - determining a preset temperature value for the discharge temperature, at which preset stable value an optimum gap thickness is to be expected, wherein the preset temperature value is determined in particular during ongoing operation; and - controlling the at least one housing cooler control mechanism such that the discharge temperature follows the preset temperature value, in particular such that the discharge temperature is adjusted to the preset temperature value as a desired temperature.

Images