Compressor device with cooling system and method for operating compressor device

Abstract

To propose a solution in which an adapted cooling system for a compressor device with a cooling device is easily formed.SOLUTION: The present invention relates to a compressor device including a compressor for compressing a gas to generate a compressed gas, in particular compressed air, and a cooling device, wherein the cooling device includes: an oil cooler; a compressed gas cooler; and a housing cooler. The oil cooler, the compressed gas cooler, and the housing cooler are prepared to perform cooling by a liquid coolant. Housing cooler control means for individually controlling a cooling flow through the housing cooler is provided for the housing cooler. The compressor device has a cooling control unit, and the cooling control unit is configured to actuate the housing cooler control means so that the cooling flow through the housing cooler is controlled independently of a cooling flow through the oil cooler.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a compressor device for compressing a gas to generate a compressed gas, particularly compressed air, and the compressor device has a cooling device. In addition, the present invention relates to an operating method of a compressor device provided with a cooling device.

Background Art

[0002] A compressor for compressing a gas to produce a compressed gas is also called a compressed gas compressor. The compressed gas compressor is used to generate a compressed gas (in many cases, compressed air). The compressed air or other compressed gas is supplied particularly for the following industrial applications. The following description regarding compressed air also applies to other compressed gases.

[0003] For functional reasons, heat is generated when compressed air is produced. Since both the compressed air and the compressor, particularly its housing, are heated, cooling is necessary. For cooling, a housing cooler for cooling the housing of the compressor or a part thereof may be provided. The housing cooler is often also called a jacket cooler or is configured as a jacket cooler. In these coolers, a cooling medium, particularly water, which is synonymous with a coolant, can flow through the housing cooler, thereby cooling the housing. Further, a compressed gas cooler may be provided, and the compressed gas cooler is arranged in a part of a conduit system for guiding the compressed gas, particularly compressed air. Here, in particular, a heat exchanger may be provided, and the cooling medium or coolant, particularly water, also flows through the heat exchanger. When generating compressed gas, oil is often also required, particularly for lubricating the components of the compressor. Such oil is also heated and can be cooled particularly by an oil cooler that may have a heat exchanger. The cooling medium or coolant, particularly water, also flows through this heat exchanger.

[0004] Effective cooling is obtained by connecting all of the above-described coolers (a plurality of which may be provided among the above-described coolers) to a primary cooling circuit. In particular, although it can occur in a series connection, the coolers may be fully or partially connected in parallel as much as possible so that a cooler does not receive the already heated water of the previous cooler.

[0005] By means of a parallel connection, each individual cooler obtains its allocated portion of the cooling water according to the flow resistance of its parallel branch. By appropriately designing the parallel branch or the cooler, each cooler obtains an appropriate amount of coolant, namely in particular water.

[0006] However, it has become clear that the need for cooling, and thus the demand for coolant, namely the demand for cooling water, can vary. In order to cope with this variation, the flow rate of the coolant in the primary circuit can be adjusted as appropriate. However, if the change in the demand for coolant varies among the individual coolers, optimal cooling in one cooler may result in overcooling or undercooling in another cooler.

[0007] In order to adjust such non-optimal cooling, an appropriate valve can be provided and the valve can be used to manually adjust the inflow of the coolant in each individual cooling respectively. However, such adjustment may take time because a maintenance technician needs to make or change appropriate settings for this purpose. Also, the result depends on the individual skills of the maintenance technician.

[0008] As a further improvement measure, an individual cooling system in which each cooler has a dedicated cooling circuit may be provided. However, such a solution is complex and thus not necessarily recommended.

[0009] Patent Document 1 discloses a cooling system for a compressor that can particularly adjust the amount of coolant.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, an object of the present invention is to address at least one of the above problems. In particular, a solution should be proposed that allows for the easy formation of a suitable cooling system for a compressor device equipped with a cooling device. At the very least, an alternative solution should be proposed to the solutions known heretofore.

Means for Solving the Problems

[0012] According to the present invention, a compressor device according to claim 1 is proposed.

[0013] Therefore, a compressor device for compressing a gas to produce compressed gas, particularly compressed air, comprising a compressor having at least one compression stage, and a cooling device is proposed. The cooling device includes an oil cooler for cooling the oil heated by the compressor, at least one compressed gas cooler for cooling all or part of the gas compressed into the compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing. The oil cooler, the at least one compressed gas cooler, and the at least one housing cooler are each prepared to achieve cooling by means of a coolant flow consisting of a liquid coolant, particularly water.

[0014] At least one housing cooler control means for individually controlling the cooling flow through the housing cooler is provided for the at least one housing cooler. Further, the compressor device has a cooling control unit, and the cooling control unit is set to operate the at least one housing cooler control means such that at least one cooling flow through the at least one housing cooler is controlled independently of the cooling flow through the oil cooler.

[0015] In this way, a compressor device including a compressor and a cooling device is provided. The compressor, also called a compression gas compressor in synonymous terms, is provided for compressing a gas to generate a compressed gas. In particular, a compressed air compressor for generating compressed air is proposed. The compressed air compressor basically generates compressed gas or compressed air in a known manner.

[0016] Furthermore, a cooling device having at least one oil cooler, one compressed gas cooler, and one housing cooler is provided. The oil cooler is provided for cooling the oil heated by the compressor. For this purpose, the oil flows from the compressor through a heat exchanger, and in the heat exchanger, its heat is released to a liquid coolant, particularly water, i.e., cooling water.

[0017] A plurality of compressed gas coolers may be provided, and they are provided for cooling the compressed gas. The compressed gas flows through this compressed gas cooler, and at this time, heat is released to the liquid coolant. It is also possible for the compressor to have a plurality of compressor stages. Therefore, even when the gas is brought to the first pressure level after the first compressor stage, it can already be regarded as compressed gas. However, as long as the compressed gas has not yet been compressed to the final pressure level, it can be considered as partially compressed gas. However, also as simplified as described above, it is also possible to provide a compressed gas cooler for this partially compressed gas that can already be called compressed gas. In this case, the compressed gas cooler may be arranged between two compressor stages. When there are at least two compressor stages, at least one compressed gas cooler for cooling the compressed gas discharged from the second compressor stage can be further provided after the second compressor stage.

[0018] The housing cooler may be provided in plurality and is provided for cooling the housing of the compressor or a part of the housing. Here, the housing of the compressor can basically be regarded as the entire physical structure of the compressor or a part thereof. That is, not only the housing in the sense of the cover of the compressor, but also the compressor as a physical object. The housing cooler may also include or mean a coolant conduit in the housing of the compressor stage of the compressor.

[0019] Therefore, it is proposed that for these coolers, an oil cooler, at least one compressed gas cooler and at least one housing cooler are each prepared to achieve cooling by a coolant flow consisting of a liquid coolant, in particular water. That is, each of these coolers has at least one flow path through which the coolant can flow. That is, the above-mentioned coolers are, in principle, coolers that use a coolant flow consisting of a liquid coolant for cooling, that is, coolers that are cooled using in particular water or cooling water. Therefore, during operation, the coolant flow flows through each cooler.

[0020] For at least one housing cooler, at least one housing cooler control means for individually controlling the cooling flow through the housing cooler is provided and can operate individually. Therefore, its control and cooling effect can function independently of other coolers.

[0021] For this purpose, the compressor device has a cooling control unit, and the cooling control unit is set to operate at least one housing cooler control means such that at least one cooling flow through at least one housing cooler is controlled independently of the cooling flow through the oil cooler. The cooling control unit is thereby implemented as a programmed control unit in the corresponding process computer, and the process computer may be set to be operably connected to at least one housing cooler control means. The housing cooler control means may be configured as a controllable valve or may have such a valve. The housing cooler control means may also include a pump, particularly a controllable pump, or may be a pump, particularly a controllable pump. The housing cooler control means can also be combined with a controllable valve.

[0022] In particular, in order to control each coolant flow individually, control means operable individually for each coolant flow are provided, whereby it is possible to control individually the cooling capacities of the oil cooler, at least one compression gas cooler and at least one housing cooler. At this time, for example, one of the coolers, for example the compression gas cooler, may have two or more partial coolers or may be divided into two or more partial coolers, for example an intermediate cooler and a final cooler, and both partial coolers can be controlled by control means respectively. Thus, for each of the two or more partial coolers, it is possible to control the respective coolant flow. For this purpose, the partial coolers are connected in parallel with each other. The individual control of each coolant flow through each partial cooler may be configured such that the distribution of the coolant flow to the partial coolers of the entire coolant flow is additionally or exclusively controlled.

[0023] Two housing coolers, also called jacket coolers, may be connected in series or in parallel. When connected in parallel, it is possible to configure the coolant flow to be distributed to these two housing coolers, and only one control means may be provided for both housing coolers. However, also in this case, since the control is performed independently of other coolers, especially the oil cooler, it is also possible to individually control the cooling flow through the housing cooler.

[0024] Preferably, a primary cooling circuit is provided for all coolers, and one or more housing coolers in the primary cooling circuit are connected in a parallel connection that is all or partially parallel to other coolers, especially oil coolers. However, this does not exclude the case where, for example, two coolers, such as two housing coolers that may be configured as jacket coolers, are connected in series. Two jacket coolers connected in series in this way can also be regarded as a common housing cooler.

[0025] Each control means may be configured as a controllable valve or as a controllable pump, or some control means may be configured as controllable valves and other control means may be configured as controllable pumps. Each control means can be regarded as an individual control means that can be operated individually. This makes it possible to always adjust the coolant flow of each cooler, and thereby operate each cooler at its optimal operating point. That is, each cooler can be operated optimally. For example, when the cooling requirement of the oil cooler increases, its coolant flow can be increased without increasing the coolant flow of other coolers.

[0026] In particular, it has been recognized that the conventional general connection between the oil cooler and the jacket cooler can be disadvantageous because the requirements for housing cooling and oil cooling are different, and a disconnection of the connection has been proposed.

[0027] At this time, it was also recognized that optimal cooling does not necessarily mean cooling as much as possible. The housing expands or contracts according to temperature, and this expansion or contraction can affect the mechanical function of the housing, especially the size of the gap between relatively moving elements. It is particularly important that at least one gap between the compressor housing and the rotor and / or between the rotors themselves is maintained within an optimal range. If the housing is cooled excessively, shrinkage occurs, resulting in contact between the rotor and the housing or between the rotors themselves, thereby continuously expanding the gap. If the housing is cooled too little, an unnecessarily large gap occurs between the rotor and the housing or between the rotors themselves, which can lead to internal backflow of the already compressed gas.

[0028] For the oil cooler, it is important that the oil viscosity is maintained within an optimal range depending on the oil temperature. If the oil is too cold, the power consumption increases, and if the oil is too hot, the wear increases.

[0029] It is also important to cool the compressed air to an optimal value after the final compressor stage. If the cooling is too little, component damage may occur or the drying of the compressed air may not function sufficiently.

[0030] With the proposed solution, it is possible to obtain a low power consumption and an optimal outlet temperature of the compressed air.

[0031] In many cases, it is desirable that the temperature in the overall coolant flow or in the sum of the coolant flows is high. In this case, as much heat as possible needs to be transferred to the heating water, which is connected to the overall coolant flow or the sum of the coolant flows, or can use the overall coolant flow or the sum of the coolant flows, for example, to save the fuel cost for heating. For this purpose, however, it is necessary to appropriately increase the temperature level so that the cooling water can be used for heating, which may be negative for the cooling of the compressor, but can be meaningful if the heat demand is appropriate. By disconnecting the control of each cooler, both can be considered.

[0032] According to one aspect, it is proposed that the cooling control unit is set to operate at least one housing cooler control means 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.

[0033] Here, further disconnection of the housing cooler is performed. Thereby, the housing cooler can be adjusted more specifically with respect to the cooling of the housing, and in particular, the optimum width of the gap between the rotor and the housing can be targeted.

[0034] According to one aspect, it is proposed that the cooling control unit is set such that the cooling flow is controlled individually, in particular by the housing cooler control means, only for at least one housing cooler, and the cooling flow is not controlled for the oil cooler and at least one compressed gas cooler, or is controlled only through common control of the entire coolant flow.

[0035] Here, in particular, the focused operation of the housing cooler, and thus the precise cooling of the housing, is important, while other coolers or other elements to be cooled are less affected by temperature fluctuations and thus require only cooling by simple control or function sufficiently without control. In this case, other coolers or other elements to be cooled are controlled only through the control of the general cooling circuit. Therefore, while maintaining a high quality of cooling of the housing, the configuration of the entire cooling system can be minimized. Similarly, such a simplified cooling circuit also avoids the causes of errors.

[0036] In particular, housing cooling or jacket cooling can be performed at a lower temperature than oil cooling. At this time, housing cooling or jacket cooling can be performed independently of oil cooling.

[0037] According to one aspect, a compressor has at least one rotor for compressing a compressed gas, at least one compressor gap is formed between the housing and the at least one rotor or between two rotors, the gap has a variable gap thickness, and a cooling control unit is configured to operate at least one housing cooler control means such that the gap thickness remains within a determinable range and / or such that the gap thickness follows a determinable target gap thickness.

[0038] In this way, the housing cooling is intensively controlled so that the compressor gap, which was simply called the gap above for simplicity, is optimized as much as possible. Here, it has been recognized that by operating the housing cooler separately, the gap thickness can be kept within a range suitable for the operation of the compressor.

[0039] For this purpose, the gap thickness is detectable, or the control is performed based on empirical values that can be recorded in a preliminary test.

[0040] However, measuring the gap thickness during operation is complex and requires adding at least one sensor, so the gap thickness can also be controlled through other values. In particular, the gap thickness can be inferred from the temperature and empirical values that are more easily measurable.

[0041] Adjusting the cooling according to the gap thickness is particularly important for dry compressors and / or screw compressors. Therefore, it is proposed that the compressor be a dry compressor and / or a screw compressor. A screw compressor is configured to compress a gas, particularly air to be compressed, by moving two meshing screws. Thereby, in particular, a continuous compression process can be carried out. A turbo compressor can also be used as a compressor.

[0042] According to one aspect, it is proposed that a cooling control unit is configured such that the gap thickness of the compressor is detected and / or estimated, and at least one housing cooler control means is controlled depending on the detected or estimated gap thickness.

[0043] According to this aspect, in order to control the clearance thickness of the compressor, it is proposed that the clearance thickness be detected, particularly measured and fed back. This control is part of a closed loop and can also be called closed-loop control.

[0044] Suitable sensors can be used for detection. This involves corresponding costs, but it is possible to detect the clearance thickness with high accuracy.

[0045] It is also possible to use a state observer to determine the clearance thickness in order to detect the clearance thickness. The state observer can use the inlet temperature of the gas to be compressed flowing into the compressor stage and its volume flow rate as input variables, and the outlet temperature of the gas at least partially compressed in the compressor stage as an output variable. The clearance thickness is the state of the state observer, and the comparison between the outlet temperature of the state observer and the detected corresponding outlet temperature can be used to adjust the state of the state observer or its model. It is also possible to estimate the clearance thickness by simulating the relationship with model calculations and comparing the calculated temperature with the measured temperature.

[0046] According to one aspect, at least one outlet temperature of the gas that is all or part of compressed into compressed gas is detected when flowing out of at least one compressor stage, a set temperature value regarding the outlet temperature at which the optimal clearance thickness is expected is determined, the set temperature value is determined particularly during operation, and it is proposed that at least one housing cooler control means be controlled such that the outlet temperature follows the set temperature value, particularly such that the outlet temperature is adjusted to the set temperature value as the target temperature.

[0047] Here, in particular, it has been recognized that an extremely accurate description of the clearance thickness can be made depending on the temperature of the gas (hereinafter referred to as the outlet temperature) that has been at least partially compressed into compressed gas when flowing out of at least one compressor stage. The relationship between the outlet temperature and the clearance thickness can be recorded in preliminary tests. The set value can basically be selected as the value at which the optimum clearance thickness is expected. That is, if the outlet temperature is adjusted to the set value, the clearance thickness is expected to have approximately the optimum value.

[0048] Therefore, it is also proposed to check or cool the size of the housing so that the size of the housing is kept constant. This is particularly important for the clearance thickness and can be reduced to considering the clearance thickness. It has been recognized that it is also possible to indirectly detect the size of the housing or the clearance thickness via the outlet temperature. In the control unit that controls the cooling, the theoretical outlet temperature when the clearance between the rotors and between the rotor and the housing is correct is compared with the detected temperature, and the cooling is controlled accordingly. The theoretical outlet temperature when the clearance thickness between the rotors and between the rotor and the housing is correct, that is, optimum, can be considered as the set temperature. In particular, in screw compressors, especially dry compressors, it is necessary to maintain the clearance thickness particularly accurately. If possible, the clearance thickness should be close to 0 μm, and it is particularly preferable to be continuously close to 0 μm.

[0049] However, it has also been recognized that the relationship between the optimum clearance thickness and the outlet temperature may depend on other variables, particularly the external temperature and the flow rate of the compressed gas. Therefore, according to one aspect, it is proposed to determine the set value during operation. In particular, it is proposed to determine the set value depending on the coolant temperature and / or the intake temperature available throughout the year. Preferably, it is proposed to determine the set value depending on the external temperature and / or the flow rate of the compressed gas.

[0050] According to one aspect, a compressor device is proposed, characterized in that a cooling control unit is set such that at least one housing cooler control means is controlled depending on at least one coolant temperature. Thereby, especially since the coolant temperature can depend on the result of the cooling by the housing cooling, the housing cooling can be controlled in a targeted manner. Therefore, it is also possible to assume closed-loop control. Preferably, a target value is specified for the coolant temperature. Thereby, the coolant can also be adjusted to a desired temperature.

[0051] In particular, the cooling control unit - the coolant temperature detected at the coolant outlet of the housing cooler, and - the coolant temperature detected downstream of the housing cooler, It is proposed that at least one housing cooler control means is set to be controlled depending on the temperature from a list having.

[0052] These temperatures best reflect the cooling performance of the housing cooler, and the housing cooler can have the greatest influence on these temperatures.

[0053] According to one aspect, a compressor device is proposed that includes a compressor for compressing gas to produce compressed gas, especially 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 all or part of the gas compressed into compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing.

[0054] Furthermore, the oil cooler, at least one compressed gas cooler, and at least one housing cooler are each prepared to achieve cooling by a coolant flow composed of a liquid coolant, especially water. Furthermore, at least one of the oil cooler and / or the housing cooler is connected in series with at least one of the compressed gas coolers, whereby the coolant flow successively passes through these serially connected coolers.

[0055] Therefore, at least a partial series connection of a plurality of different coolers is provided. In particular, a series connection of an oil cooler and a compressed gas cooler is proposed. With the series connection, the return temperature of the coolant increases, and a higher water outlet temperature can be obtained throughout the coolant flow. Thereby, the waste heat generated can be utilized more effectively. At the same time, the jacket cooler and the oil cooler can be sufficiently cooled when the inlet temperature of the water is high.

[0056] Nevertheless, in the proposed series connection, the oil cooler and the housing cooler can be connected in parallel, so that the housing cooler can still be reliably controlled independently of the oil cooler.

[0057] According to one aspect, the coolant flow through these coolers connected in series first flows through the oil cooler and then through at least one compressed gas cooler, so it is proposed that coolant at a lower temperature than at least one compressed gas cooler flows through the oil cooler.

[0058] Since the coolant in the compressed gas cooler rises to a temperature that cannot be reached by some oil coolers, a high outlet temperature can be obtained especially in this order.

[0059] According to one aspect, it is proposed that a cooling circuit is provided for cooling the heated coolant again or supplying it for further use, especially for utilizing the heat of the coolant, by supplying the coolant at the cooling circuit inlet and withdrawing the coolant heated by the cooler at the cooling circuit outlet, and that the compressor device has a cooling control unit. The cooling control unit is set to control the compressor device so that the coolant at the cooling circuit outlet has a temperature of 85°C to 95°C, especially 90°C to 95°C.

[0060] For this purpose, the cooling control unit can implement a corresponding control program that executes the corresponding method steps. Furthermore, such a cooling control unit is connected to the corresponding control means of the cooler, particularly the valve, so that the control means can be actuated by the cooling control unit. It is also possible to provide a connection to at least one pump for driving the entire coolant flow.

[0061] In order to control the temperature of the coolant at the cooling circuit outlet, it is possible to measure and feedback this temperature, whereby the cooling control is incorporated into a closed loop or forms a closed-loop control.

[0062] Temperatures in the range of 85°C to 95°C, particularly 90°C to 95°C, may be regarded as high temperatures, and in other embodiments, further references to high temperatures may be defined by these temperature values. In particular, the temperature of 95°C is high, but it has been recognized that it is still below the temperature of boiling water under atmospheric pressure. Similarly, although it may be more important in some cases, in the compressor device, the cooling water is usually pressurized and evaporates at a higher temperature, so it is also possible to maintain a limit of 110°C. Furthermore, it should also be noted that other regulations may apply to temperatures above 110°C. Therefore, the described temperatures relate particularly to cooling water as the coolant.

[0063] According to one embodiment, it is proposed that the compressor device be configured such that the coolant first flows through the oil cooler and then through at least one of the at least one housing cooler.

[0064] Therefore, in order to obtain a high temperature of the coolant at the cooling circuit outlet, the coolant can first be heated in the oil cooler and then further heated in the housing cooler.

[0065] The housing cooler can be composed of a plurality of housing coolers that may be connected in parallel or in series. Further heating of the coolant in the housing cooler is performed in both variants, and the described effects can be obtained.

[0066] According to one aspect, a plurality of compressed gas coolers are provided, and the compressor device is configured such that after the coolant passes through the oil cooler, it passes through a plurality of compressed gas coolers connected in parallel in particular, and the coolant passes through these plurality of compressed gas coolers in parallel.

[0067] In this way, the compressed gas cooler continues to heat the coolant even after the coolant is heated by the oil cooler. By connecting in parallel the compressed gas coolers, each of which is configured as a heat exchanger or can include a heat exchanger, both heat exchangers can obtain the same low water inlet temperature, and in the countercurrent flow, that is, in the compressed gas flow passing through each heat exchanger, it is possible to cool the compressed air to near the water inlet temperature.

[0068] Since the inlet temperature of the compressed air generally far exceeds 100°C and is particularly in the range of about 120°C to 250°C, if necessary, both compressed gas coolers can be used to heat water, that is, cooling water, to a desired temperature.

[0069] According to one aspect, the compressor device is characterized in that a plurality of compressed gas coolers are divided into a plurality of groups of compressed gas coolers, the compressed gas coolers in each group of compressed gas coolers are connected in parallel with each other, and the groups of compressed gas coolers are connected in series with each other. For this purpose, in particular, it may be defined that the first compressed gas cooler and the second compressed gas cooler are connected in parallel with each other and are connected in series with the third compressed gas cooler and the fourth compressed gas cooler connected in parallel with each other.

[0070] Therefore, in particular, the compressed gas coolers (which can be defined for all compressed gas coolers in all aspects) configured as heat exchangers receive the coolant having the same water inlet temperature in the parallel connection. In the countercurrent flow, the compressed gas cooler can cool the compressed air to near the water inlet temperature.

[0071] At this time, after the coolant is heated by the compression gas cooler of the first compression gas cooler group, the compression gas cooler of the subsequent compression gas cooler group or the second compression gas cooler group continues to heat the coolant.

[0072] According to the present invention, a method for controlling a compressor device is further proposed. The compressor device has a compressor for compressing a gas to generate a compressed gas, particularly compressed air, in particular a screw compressor, and the compressor has at least one compression 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 compression gas cooler for cooling the gas that is wholly or partly compressed into a compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing.

[0073] The oil cooler, at least one compression gas cooler, and at least one housing cooler are each prepared to achieve cooling by means of a coolant flow composed of a liquid coolant, particularly water. For at least one housing cooler, at least one housing cooler control means for individually controlling the cooling flow through the housing cooler is provided, and the compressor device has a cooling control unit. The cooling control unit operates the at least one housing cooler control means so that at least one cooling flow through the at least one housing cooler is controlled independently of the cooling flow through the oil cooler.

[0074] In particular, it is proposed that the method functions as described in relation to the compressor device. In particular, the method functions as described in relation to the compressor device or the corresponding control unit that is respectively set to execute the corresponding method or method step. In particular, the following method or part of the method is proposed, and its implementation and advantageous effects are also described above in relation to the aspect of the compressor device.

[0075] According to one aspect, the cooling control unit controls the cooling flow individually, particularly using the housing cooler control means, only for at least one housing cooler, while for the oil cooler and at least one compressed gas cooler, a method is proposed where the cooling flow is either not controlled or is controlled only through common control of the entire coolant flow.

[0076] According to one aspect, a compressor has at least one rotor for compressing compressed gas, and at least one compressor clearance is formed between the housing and the at least one rotor, and the clearance has a variable clearance thickness. It is proposed that the cooling control unit operates at least one housing cooler control means such that the clearance thickness remains within a preset range and / or follows a preset target clearance thickness.

[0077] According to one aspect, it is proposed that the clearance thickness of the compressor is detected and / or estimated using the cooling control unit, and at least one housing cooler control means is controlled depending on the detected or estimated clearance thickness.

[0078] According to one aspect, using the cooling control unit, at least one outlet temperature of the gas that is all or partly compressed into compressed gas is detected when it is discharged from at least one compressor stage, a set temperature value regarding the outlet temperature at which the optimal clearance thickness is expected is determined, the set temperature value is determined particularly during operation, and at least one housing cooler control means is controlled such that the outlet temperature follows the set temperature value, particularly such that the outlet temperature is adjusted to the set temperature value as the target temperature.

[0079] Hereinafter, with reference to the accompanying drawings, based on the embodiments, the present invention will be illustrated in more detail by way of example.

Brief Description of the Drawings

[0080]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0081] FIG. 1 shows a compressor device 100 including a compressor 130 having a first compressor stage 131 and a second compressor stage 132. The compressor 130 and other elements are also schematically shown.

[0082] Furthermore, an intercooler 133 and a final cooler 134, also called a compressed air intercooler or a compressed air final cooler, are provided. The intercooler is shown here as part of the compressor 130. This is because although the intercooler is arranged between the first compressor stage and the second compressor stage, it can also be configured as a separate element. Therefore, the final cooler 134, which is not shown as part of the compressor 130, may be part of the compressor in another embodiment.

[0083] A first jacket cooler 141 and a second jacket cooler 142 are provided to cool the first compressor stage 131 and the second compressor stage 132. The jacket coolers 141 and 142 are integrated with the compressor stages 131 and 132, respectively.

[0084] Furthermore, an oil cooler 135 is provided. The oil cooler 135 is connected to the oil circuit 145 of the compressor 130. For clarity, the connection between the oil circuit 145 and the compressor 130 is not shown in this figure or in most of the remaining figures.

[0085] To cool the entire compressor device 100, a primary cooling circuit 150 having a coolant supply section 151 and a coolant return section 152 is provided. To the above-described coolers, that is, the intercooler 133, the final cooler 134, the first jacket cooler 141 and the second jacket cooler 142, and the oil cooler 135, a low-temperature coolant, water in the illustrated example, is supplied through this primary cooling circuit, that is, through the coolant supply section 151. The water thus heated by the cooler flows back to the heat sink 154, which is only abstractly shown, through the coolant return section 152. The heat sink 154 may be a component of the compressor device 100, but it is no longer necessary to be a component. A primary heat exchanger 156 is provided in or as the heat sink, and the common coolant flow in the primary cooling circuit 150 is obtained by the primary coolant pump 158.

[0086] The above-described coolers, that is, the intercooler 133, the final cooler 134, the first jacket cooler 141 and the second jacket cooler 142, and the oil cooler 135 are connected in parallel in the primary cooling circuit. Therefore, coolant is supplied to all of the above-described coolers from the primary cooling circuit 150. For this purpose, each cooler is connected in parallel to the primary cooling circuit through an intercooler line 163, a final cooler line 164, a jacket cooler line 166, and an oil cooler line 165.

[0087] Therefore, the jacket cooler line 166 first supplies the first jacket cooler 141 and the second jacket cooler 142. At this time, in the example shown in FIG. 1, the first jacket cooler 141 and the second jacket cooler 142 are connected in parallel.

[0088] To adjust the coolant flow or the ratio thereof to each other, manually adjustable valves, that is, a manual intercooler valve 173, a manual jacket cooler valve 176, and a manual oil cooler valve 175 are provided. A final cooler control valve 174 is provided to adapt the intercooler 133 and the final cooler 134 to each other.

[0089] Furthermore, a primary control valve 159 is provided, and the primary control valve 159 can control the overall reflux of the coolant in the reflux of the coolant.

[0090] Furthermore, an oil bypass valve 185 is also provided, and the flow of oil through the oil cooler 135 can be controlled using the oil bypass valve 185.

[0091] FIG. 1 shows a cooling concept that functions in this way, but further improvements have been recognized for this cooling concept. In particular, it has become clear that the individual coolers are not fully matched to each other, at least partially, and the degree of cooling is different from each other. In order to obtain good and uniform, and thus efficient, cooling of the compressor device 100, it has been recognized that there is a need for improvement here. Similarly, it has also been recognized that there is a need for cooling adapted to each cooler, which may also depend on the operating state of the compressor device, especially its cooling device. In particular, the need for adapted cooling may depend on the final pressure, the rotational speed, the intake temperature, the inlet temperature T10 of the cooling water, and the desired outlet temperature of the cooling water at the temperature measurement point T14. In particular, it may depend on the outlet temperature T100 of the compressed air and the desired oil temperature T60 or T66.

[0092] It should be noted that the compressor device 100 is thus composed of the compressor 130 and a number of the above-mentioned coolers including the primary cooling circuit, and the above-mentioned coolers including the above-mentioned primary cooling circuit (and in some cases, an additional secondary cooling circuit) can be understood as the cooling device of the compressor device.

[0093] In particular, the following disadvantages exist:

[0094] The distribution of the volume flow rate of water to the parallel coolers had to be set manually, but the distribution of the heat output, and thus the water temperature, can vary greatly depending on the operating point.

[0095] If the desired outlet temperature at the temperature measurement point T14 is higher, it is necessary to cool the oil cooler and the jacket cooler separately with cooling water, which can be done through the secondary cooling system.

[0096] Due to various disturbance variables, there may be a large difference between the individual outlet temperatures T11, T12, T13, T16.

[0097] As a result, the use of cooling water is often ineffective. The stages may be damaged by cooling water that is too cold.

[0098] Similarly, the following drawbacks were identified.

[0099] The outlet temperature of the water was controlled by a common valve V14.

[0100] The oil temperature was controlled through a bypass to the oil cooler. In most cases, more water than necessary was supplied to the oil cooler so that it could be cooled sufficiently even in the most unfavorable cases.

[0101] In most cases, more water than necessary was supplied to the final cooler so that it could be cooled sufficiently even in the most unfavorable cases. To make it possible to correct different heat outputs in the final cooler, an adjustment was made through valve V12 so that the temperature T11 = T12.

[0102] In most cases, the jacket cooler is supplied with too little water to reach the desired outlet temperature T14, but there may also be cases where the water is excessive and too cold, which can cause damage to the stages.

[0103] The intermediate cooler is supplied with only enough water to reach the desired mixed outlet temperature T14.

[0104] If the components temporarily require better cooling, V14 opens further and all heat exchangers are supplied with more water, but the desired water outlet temperature T14 can no longer be reached.

[0105] In FIG. 1, it is also particularly recognized that the oil cooler 135, the jacket coolers 141 and 142, which can also be called housing coolers, and the compression gas coolers, namely the intermediate cooler 133 and the final cooler 134, are all connected in parallel. Although this structure has been proven to be effective in terms of cooling, due to the parallel connection, the above-mentioned coolers are always supplied with a coolant at a low temperature, and the low-temperature coolant cannot raise the temperature to a very high level within each cooler. As a result, the temperature at the outlet of the primary cooling circuit 150 to the heat exchanger does not become very high. As a general value, this temperature can reach, for example, about 65°C. That is, the waste heat cannot be utilized effectively.

[0106] FIG. 2 shows a compressor device 300 according to an embodiment. Similar to the compressor device 100 according to FIG. 1, the compressor device 300 has a compressor 30 having a first compressor stage 1 and a second compressor stage 2 provided with a first jacket cooler 41 and a second jacket cooler 42. In the illustrated embodiment, the first jacket cooler 41 and the second jacket cooler 42 are connected in series with each other.

[0107] Furthermore, an intermediate cooler 3 and a final cooler 4 for cooling the compressed gas respectively are provided. At this time, the intermediate cooler 3 cools the partially compressed compressed gas, and the final cooler 4 cools the fully compressed compressed gas.

[0108] Similarly, an oil cooler 5 for cooling the oil flowing through the compressor 30 is provided.

[0109] All of the above-mentioned coolers 3, 4, 5, 41 and 42 are connected to the primary cooling circuit 50, and the coolant is supplied from the primary cooling circuit 50. In order to operate the primary cooling circuit, similar to that shown in FIG. 1, a primary heat exchanger 10 and a primary coolant pump 12 are provided. The primary heat exchanger 10 and / or the primary coolant pump 12 may or may not form part of the compressor device respectively.

[0110] Each cooling element connected to the primary cooling circuit 50 can be controlled manually through its own, i.e., individual, control means, in particular operable control means. For this purpose, each control valve V11, V12, V13 and V16 is provided, and each control valve is arranged in a coolant line connected in parallel to the primary cooling circuit to control the coolant flow through each cooling element. In this embodiment and all other embodiments, the control valve can be simply referred to as a valve. The first jacket cooler 41 and the second jacket cooler 42 can be operated by the control valve V13. Alternatively, if the first jacket cooler 41 and the second jacket cooler 42 are connected in parallel with each other, separate valves are also possible.

[0111] The above-mentioned cooling elements, i.e., the intermediate cooler 3, the final cooler 4, the oil cooler 5, the first jacket cooler 41 and the second jacket cooler 42, can thus operate individually. In particular, the jacket coolers 41, 42 can be controlled independently of the oil cooler through the valve V13.

[0112] In particular, it is stipulated that the temperature of the coolant, i.e., the cooling water, is detected and taken into account to control each cooling element or to control the control valves V11 to V13 and V16. For this purpose, corresponding temperature measurement points T2, T31, T4 and T9 to T16, T19, T20, T29 and T60 are provided. Thereby, the cooling can be controlled depending on these temperatures.

[0113] In particular, the control of the first jacket cooler and / or the second jacket cooler can be performed depending on the outlet temperature of the compressed gas when discharged from the first compressor stage 1 and / or the second compressor stage 2, that is, depending on the temperature of the compressed gas detected at the temperature measurement points T2 or T4. For this purpose, the jacket coolers 41 or 42 can be controlled together through the valve V13, or can be controlled individually if they are connected in parallel. The valve V13, or two corresponding valves in the case of parallel connection, can be called housing cooler control means. Through this, the housing cooler can be controlled independently of the oil cooler. As a result, centralized control depending on the temperature of the jacket cooler becomes possible. Thereby, the control of the jacket cooler can be concentrated particularly on the control of the gap thickness between the rotors or between the rotor and the housing.

[0114] The oil cooler can be controlled through the valve V16 independently of the housing cooler.

[0115] The oil temperature is detected at the temperature measurement point T60. It is also possible to detect other temperatures, such as the outlet temperature T100 as the outlet temperature from the compressor device.

[0116] Preferably, all these temperatures can be included in the control of the cooler, and thus in the control of the control valves V10 - V13, V16, and V19. However, it is not necessary to consider all the temperatures. Preferably, at least one temperature is considered.

[0117] The compressor device according to FIG. 2 has compressor stages 1 and 2 equipped with a compressed air intercooler 3, a compressed air aftercooler 4, an oil cooler 5, and jacket coolers 41 and 42.

[0118] In this embodiment, for example, there is a cooling water circuit 50 having a heat exchanger 10 for heat recovery. The heat exchanger 10 can be used for waste heat utilization, but a cooling system not used for waste heat utilization can also be used. However, the advantages are particularly significant when combined with waste heat utilization.

[0119] Supplementally, a secondary cooling circuit 580 is provided, and the secondary cooling circuit 580 is provided to cool the entire coolant flow of the primary cooling circuit 50. For this purpose, a link is provided via the primary-secondary heat exchanger 9.

[0120] The secondary cooling circuit 580 can release heat again through the secondary heat exchanger 11, and its coolant flow can be driven by the secondary coolant pump 13.

[0121] The secondary cooling circuit 580 can cool the coolant flow of the primary cooling circuit, particularly the entire coolant flow. For this purpose, the primary-secondary heat exchanger 9 is provided. Furthermore, a control valve V10 is provided for operation, and the control valve V10 is arranged in the coolant line of the primary-secondary heat exchanger 9. The operation of the control valve V10 can be performed depending on the downstream temperature of the coolant leaving the primary-secondary heat exchanger 9. For this purpose, a temperature measurement point T10 is provided. The temperature of the coolant flowing through the control valve V10 can be detected at the temperature measurement point T24.

[0122] The heat exchanger 9 is used when the inlet temperature T9 of the water to the compressor is too high and the heat exchanger cannot sufficiently cool the compressor, for example, the oil. In this case, the inflowing water can be cooled through the heat exchanger 9 to a sufficiently low desired temperature T10.

[0123] A similar situation also occurs when the amount of heat required in the primary heat exchanger 10 is small or not required at all. In this case, the temperature T9 can reach approximately the temperature T14. The lower the temperature T31 and the lower or optimally lower the temperature T13 (see Figure 2), the lower the input power of the compressor. Therefore, when the required amount of heat is small, an attempt is made to keep the temperature T10 as low as possible.

[0124] The heat exchanger 9 is proposed particularly when the inlet temperature of the water at the temperature measurement point T9 of the compressor is too high and the heat exchanger cannot sufficiently cool the compressor, for example, the oil. In this case, the inflowing water can be cooled through the heat exchanger 9 to a sufficiently low desired temperature T10.

[0125] A similar situation occurs when the amount of heat required by the exchanger 10 is small or not required at all. In this case, it is possible for the temperature at T9 to reach approximately the temperature at T14. The lower the temperature at T31 and the lower / suitably low the temperature at T13, the lower the input power of the compressor. Therefore, when the required amount of heat is small, an attempt is made to keep the temperature at T10 as low as possible.

[0126] Through the four control valves V11, V12, V13, and V16, the volume flow rate of water through the components 3, 4, 5, 1, 2, or 41, 42 can be individually and optimally adjusted.

[0127] Closed-loop control of the outlet temperature T14 of the (mixed) water of the compressor is possible through the above-mentioned valves V11, V12, V13, V16.

[0128] In particular, in order to eliminate the formation of steam bubbles and the associated risks, it is proposed to incorporate the temperatures after the first compressor stage and the second compressor stage, i.e., the temperatures at the measurement points T11 and T12 shown in the figure.

[0129] In order to control the volume flow rate of water through the oil cooler, it is proposed to include at least one oil temperature, for example, the oil temperature at the measurement point T60, in the control. Alternatively, component temperatures, such as the bearing outer ring temperature, can also be used.

[0130] Particularly preferably, in order to protect the second compressor stage from excessive temperature and in particular to increase efficiency, it is proposed to include the inlet temperature of the compressed gas to the second compressor stage, and thus in particular the temperature at the measurement point T31, in the control.

[0131] In the configuration according to FIG. 2, furthermore, at the outlet of the cooling circuit, i.e., the outlet to the heat exchanger 10, and thus at the temperature measurement point T14, a high temperature of the coolant can be achieved. A temperature of 85°C to 95°C, particularly 90°C to 95°C, can be achieved. This can be achieved by connecting the first compressed gas cooler 3 and the second compressed gas cooler 4 in series with the jacket coolers 41, 42 and the oil cooler 5. Thereby, the first compressed gas cooler 3 and the second compressed gas cooler 4 obtain a coolant at a temperature higher than the temperature T10, so that the preheated coolant can be further heated.

[0132] Thereby, a higher temperature of the coolant can be obtained as a whole. Therefore, the waste heat in the coolant can be utilized more effectively.

[0133] In the embodiment of FIG. 2, a primary bypass control valve V19 is provided. The primary bypass control valve V19 can also be referred to as the bypass valve V19 for short. Through the bypass valve V19, a part of the entire coolant flow of the primary cooling circuit 50 can be supplied to the intermediate cooler 3 and the final cooler 4 by the first jacket cooler 1, the second jacket cooler 2, and the oil cooler 5 before tapping (or after tapping according to one embodiment). In this case, that is, a series connection of the oil cooler 5, the first jacket cooler 41, and the second jacket cooler 42 with the two compressed gas coolers, i.e., the intermediate cooler 3 and the final cooler 4, is specifically provided. Therefore, the two compressed gas coolers receive the coolant heated by the oil cooler 5 and the first jacket cooler 41 and the second jacket cooler 42. However, the low-temperature coolant that has not yet passed through the oil cooler 5 and the first jacket cooler 41 and the second jacket cooler 42 can be supplied to the two compressed gas coolers through the valve V19, thereby reducing the volume flow rate to the oil cooler. This can be used particularly during low-temperature startup, as will be described below.

[0134] The series connection of the oil cooler 5 and the two compression gas coolers, namely the intermediate cooler 3 and the final cooler 4, of the first jacket cooler 41 and the second jacket cooler 42, is proposed as an optimized connection for waste heat utilization at a high temperature level. The oil cooler 5 and the jacket coolers 41, 42 receive the maximum volume flow rate of the primary water having the temperature T10 that has not yet been preheated.

[0135] The primary bypass control valve V19 is used particularly during low-temperature start-up. When the oil has not yet reached the operating temperature, the primary bypass control valve V19 is open. When the coolant is still at a low temperature, that is, in the case of low-temperature water having a low temperature particularly at the temperature measurement points T10, T13, T15, the control valve V13 may be closed. However, it has been recognized that the valves V11 and V12 need to control a sufficient water flow very quickly after low-temperature start-up. Therefore, it is proposed to open the valve V19 during low-temperature start-up. During operation, when the low-temperature start-up process is completed, it is proposed to close the bypass valve V19 slightly again so that the oil cooler and the jacket cooler can obtain a relatively high coolant volume flow rate.

[0136] The set outlet temperature of the water at the measurement point T14, that is, the target temperature, can only be obtained by mixing the partial coolant flows having the temperatures T11 and T12. In these two coolers, a higher outlet temperature can be obtained. In particular, a high outlet temperature T14 can be obtained thereby.

[0137] It has been recognized that the following advantages occur.

[0138] The waste heat from the oil cooler and the waste heat from the jacket cooler can be used for waste heat utilization even at the water temperature, that is, the coolant temperature, which was conventionally impossible.

[0139] Regarding the outlet temperature T14, it is possible to achieve a higher target temperature. This is because only the partial coolant having temperatures T11 and T12, or at the measurement points T11 and T12, is mixed, thereby generating a mixing temperature, and the mixing temperature is not mixed so as to be cooled by the coolant having temperatures T16 and T15. As the outlet temperature T14 of the coolant in the primary cooling circuit, a temperature of 85°C to 95°C, particularly 90°C to 95°C, can be obtained.

[0140] Therefore, even when a hot water supply system is required, it is possible to obtain a high temperature and at the same time a high output in the water supply system.

[0141] In the following, some of the important aspects of the embodiment according to FIG. 2 will be summarized.

[0142] There are two cooling water circuits 50 and 5800.

[0143] The coolers 3, 4, 5 and the jacket coolers of stages 1 and 2 are arranged in the primary circuit 50. At this time, the oil cooler 5 and the jacket coolers of stages 1 and 2 are first connected in parallel. Next, the intermediate cooler 3 and the final cooler 4 are connected in series. The intermediate cooler 3 and the final cooler 4 are similarly connected in parallel.

[0144] The secondary circuit 580 cools the primary circuit 50 as necessary.

[0145] This connection form is particularly advantageous during heat recovery through the heat exchanger 10, which can also be referred to as waste heat utilization.

[0146] The following advantages occur.

[0147] A higher heat recovery capacity is possible, and in some cases, the required cooling water is reduced or becomes unnecessary.

[0148] Closed-loop control to a higher water outlet temperature T14, i.e., the possibility of setting a higher target value for this water outlet temperature T14, i.e., for example, instead of ~80 °C or 85 °C as in the prior art, there is a possibility of setting a higher target value than the prior art, such as 90 °C to 95 °C.

[0149] The following further advantages occur.

[0150] By performing closed-loop control of the individual volume flow for each heat source, optimized closed-loop control of the outlet temperature T14 of the mixed water becomes possible.

[0151] The user can predetermine the water outlet temperature T14.

[0152] The oil cooler receives only the amount of water necessary to achieve the optimum oil temperature. Figure 3 below illustrates different embodiments, but for clarity and to show the relationships more clearly, reference numerals that are partially identical to those of the embodiment of Figure 2 are used. However, the elements do not necessarily have to be actually identical.

[0153] Figure 3 shows an embodiment of a compressor device 300 provided with a jacket cooler heat exchanger 6 for a first jacket cooler 41 and a second jacket cooler 42. The jacket coolers 41, 42 may also be connected in series here. The coolant flow through the jacket coolers 41, 42 is driven by a jacket cooler pump 14, and thus drives a dedicated cooling circuit that can be called a compressor cooling circuit 32 as the coolant flows through the corresponding jacket regions of the first compressor 1 and the second compressor 2. The jacket cooler pump 14 is thus a cooling water pump for the compressor cooling circuit 32. The compressor cooling circuit 32, or the coolant therein, passes through the first jacket cooler 41 and the second jacket cooler 42 and is led through the primary side of the heat exchanger 6, i.e., the jacket cooler heat exchanger 6. The coolant from the primary cooling circuit 50 flows through the secondary side of the jacket cooler heat exchanger 6. The corresponding coolant flow through the jacket cooler heat exchanger 6 from the primary cooling circuit 50 is controlled by a control valve V13.

[0154] The temperatures of the temperature measurement points T9, T10, T11, T12, T14, T16, T19, T20, T23, T24, T28, T29, T31, T51, T52, T85, and T100 are recorded as the relevant temperatures. Further, the pressure dew point M85 downstream of the adsorption dryer 20 may also be recorded.

[0155] Preferably, the valve V13 operates depending on the temperature of the coolant leaving the first jacket cooler 41 and / or the second jacket cooler 42.

[0156] The temperature Txx at the measurement point has "xx" as a placeholder for the temperature or the respective number of the measurement point, and hereinafter and above, for the sake of simplicity and synonymously, may be denoted as the temperature Txx.

[0157] During cold start, since V13 remains closed, there is no coolant flow at T23. Therefore, no temperature rise occurs at the temperature measurement point T23. When the temperature of the coolant leaving the first jacket cooler 41 and / or the second jacket cooler 42 rises, the valve V13 is opened by the control unit, which may also be expressed as "adjusted to open". Here, finally, the temperature of the measurement point T23 can be used for closed-loop control.

[0158] The control valve V13 can be called the jacket cooler control valve and controls the coolant flow through the jacket cooler heat exchanger 6. In other embodiments, it is also possible to control the coolant volume flow rates of the jacket coolers 41, 42. The valve V13 controls the temperature of the coolant leaving the first jacket cooler 41 and / or the second jacket cooler 42.

[0159] Figure 3 further includes a second final cooler 7 and a third final cooler 8, which may also be referred to as the second compressed air final cooler and the third compressed air final cooler, and are specifically configured as heat exchangers here. The second final cooler 7 and the third final cooler 8 are arranged in the compressed gas line 34, that is, on the downstream side of the compressed gas downstream of the final cooler 4 or the compressed gas final cooler 4. Thereby, additional cooling of the compressed gas is obtained. The third compressed air final cooler or the compressed gas final cooler can also be referred to synonymously with the dryer final cooler.

[0160] As also shown in the embodiment of Figure 3, it is particularly preferred to use a dryer for compressed gas, especially the adsorption dryer 20 incorporated in the compressed gas line 34. In the case of a refrigeration dryer, it is also meaningful to add a final cooler 7 to adjust the dew point and the outlet temperature. However, the third compressed air final cooler 8 does not bring much significance as shown in the case of a refrigeration dryer. In a refrigeration dryer, the third compressed air final cooler 8 may rather be used to heat the compressed air. Therefore, the use of an adsorption dryer is particularly proposed here. In an adsorption dryer, the third compressed air final cooler 8 is particularly used to cool the compressed air.

[0161] Here, it is particularly proposed that the compressed gas dryer 20 is arranged on the downstream side of the second final cooler 7 and the upstream side of the third final cooler 8 in the flow direction of the compressed gas.

[0162] In order to control the coolant flow through both the second final cooler 7 and the third final cooler 8, control valves V25 or V28 are provided respectively. Therefore, the second final cooler 7 and the third final cooler 8 can be controlled independently of each other.

[0163] Furthermore, temperature measurement points T25 or T28 are provided respectively and assigned to the second final cooler 7 or the third final cooler 8, and the corresponding control valves V25 or V28.

[0164] What was specifically recognized here is that the dryer is supported by the second final cooler 7 and that the pressure dew point downstream of the dryer can be affected. However, this also results in a decrease in the outlet temperature from the dryer, which may or may not be desirable.

[0165] By installing a heat exchanger, i.e., a final cooler, downstream of the dryer, the compressed air can be brought to an optimal temperature for subsequent applications. In the case of an adsorption dryer, the air at the outlet is clearly warmer than the air at the inlet, so additional cooling may be required.

[0166] The control valve V25 that controls the coolant flow through the second final cooler 7 can control the coolant flow depending on the temperature detected at the temperature measurement point T25. However, preferably, the outlet temperature T52 of the air is adjusted by the valve V25. In a facility with a dryer, the target value of this temperature T52 is determined by a control cascade from the desired pressure dew point downstream of the dryer. In a facility without a dryer, the target value of the temperature T52 is determined from the target value of the externally specified temperature T100.

[0167] Closed-loop control by the temperature T25 or the temperature difference T25 - T20 is also possible according to a further embodiment.

[0168] That is, the control valve V25 controls the coolant flow depending on the outlet temperature of the compressed air at the temperature measurement point T52 from the second final cooler 7.

[0169] Similarly, it is defined that the control valve V28 that controls the coolant flow through the third final cooler 8 adjusts the outlet temperature T100 of the compressed air. According to an alternative embodiment, closed-loop control by the temperature T28 or the temperature difference T28 - T20 is provided.

[0170] Therefore, this is done depending on the temperature at the temperature measurement point T28, i.e., it is possible to control the coolant flow depending on the coolant temperature at the outlet of the third final cooler 8.

[0171] In the illustrated embodiment, additionally, a secondary cooling circuit 580 is defined as cooling the coolant flow of the primary cooling circuit 50, in particular the entire coolant flow, and for this purpose a corresponding primary-secondary heat exchanger 9 is provided. Furthermore, a control valve V10 is provided for operation, and the control valve V10 is arranged in the coolant line and thus also in the coolant flow, i.e., in the secondary cooling circuit of the primary-secondary heat exchanger 9. The operation of the control valve V10 can be carried out depending on the downstream temperature of the coolant leaving the primary-secondary heat exchanger 9. For this purpose, a temperature measurement point T10 is provided. The temperature of the coolant flowing through the control valve V10 can be detected at the temperature measurement point T24.

[0172] In the embodiment shown in FIG. 3, it is proposed to split the primary coolant pump 12 according to FIG. 2, i.e., to provide two primary coolant pumps 12a, 12b, i.e., one before and one after the primary-secondary heat exchanger 9. Furthermore, a primary circuit bypass 21 may be provided, and a part of the entire coolant flow of the primary cooling circuit 50 passes through the primary heat exchanger 10 through the primary circuit bypass 21. By means of the internal pump 12b, in conjunction with the bypass 21 and the heat exchanger 9, the operation of the compressor and thus the supply of compressed air can be maintained even when the external heat sink 10 and / or the pump 12a are not available. This can be the case, for example, during maintenance work, or repair work, or when there is seasonal heat demand.

[0173] The external pump 12a is configured in particular with respect to the external pressure loss, i.e., the pressure loss in the heat exchanger 10 and the piping, and possibly other elements. The internal pump 12b may be operated together for assistance or may only standby for cases where necessary. The internal pump 12b is switched on only when the primary coolant pump 12a does not supply water or supplies too little water, otherwise the compressor may become too hot and a shutdown may occur.

[0174] Furthermore, a pressure dew point temperature measurement point M85 is provided downstream of the drying device 20. The pressure dew point temperature is determined at this point, and cooling can be controlled depending on the pressure dew point temperature. In particular, it has been proposed to control the second final cooler 7 and / or the valve V25 depending on the pressure dew point temperature.

[0175] At this time, the valve V25 has a great effect when an additional final cooler 7 is present.

[0176] Furthermore, the dew point M85 can be improved by the valve V11 (which reduces the opening to increase the temperature T31) and the valve V12 (which increases the opening to lower the temperature T51).

[0177] When the temperature T31 is increased, the regeneration temperature of the dryer becomes higher, so the dew point M85 can be lowered.

[0178] It has been recognized that as long as an additional final cooler 7 is present, the valve V25 exerts the greatest effect. Furthermore, the valve V11 by reducing the opening of the valve V11 to increase the temperature T31 and the valve V12 by increasing the opening of the valve V12 to lower the temperature T51 can improve the dew point M85.

[0179] It has also been recognized that by increasing the temperature T31, the regeneration temperature of the dryer, particularly the adsorption dryer 20, can be increased, thereby obtaining a lower dew point M85.

[0180] In particular, the pressure dew point downstream of the dryer is important. At the inlet of the dryer, the compressed air is usually 100% saturated. Therefore, on the premise that the condensed condensate is separated and discharged as completely as possible upstream of the dryer, the temperature and the pressure dew point approximately coincide here.

[0181] The temperature of the compressed gas at the inlet of the dryer is particularly important for the result of drying.

[0182] If the condensate is not separated upstream of the dryer, the result of drying will be slightly worse. However, the compressor should be configured such that the already condensed condensate is separated in advance.

[0183] The condensate separator and the condensate discharger are not shown in the drawings, partly for the sake of simplicity.

[0184] The embodiment according to FIG. 3 is configured such that the second final cooler 7 and the third final cooler 8 are connected in parallel to the primary cooling circuit 50. A secondary cooling circuit 580 is provided in the same way, and the secondary cooling circuit 580 is configured in the same way as in FIG. 2 and is connected to the primary cooling circuit 50.

[0185] The intermediate cooler 3 and the final cooler 4 (which can also be referred to synonymously as the first final cooler 4 in this embodiment and other embodiments) are not connected to the primary cooling circuit 50 in parallel connection as in the embodiment of FIG. 2, but are connected in series connection. In the series connection, the coolant is supplied to the intermediate cooler 3 and the final cooler 4 from the primary cooling circuit 50 after flowing through other coolers. The primary bypass control valve V19 as shown in FIG. 2 is not required here. This is because a sufficient volume flow rate of water always flows through, especially through the second final cooler 7 together with the control valve V25, so that the serially connected intermediate cooler 3 and final cooler 4 can always obtain a sufficient volume flow rate. Nevertheless, an alternative solution is shown as a precaution. This primary bypass control valve V19 can be used when the valve V28 is closed because the temperature T100 is low enough and the valve V25 is closed because the pressure dew point M85 is low enough. In this case, the valve V19 must be opened so that the heat exchanger 3, in particular, receives more and cooler water downstream of the compressor or the compressor stage 1. This is because this improves the efficiency of compression.

[0186] Nevertheless, the embodiment can also be realized by the primary bypass control valve V19 and the heat exchanger control valve V25. This embodiment would be meaningful in special cases where warmer compressed air is required in winter. In this case, valves V28 and V25 would have to be closed so much that, with respect to the aftercooler, sufficient water cannot be supplied to the intercooler and the aftercooler without opening the primary bypass valve V19.

[0187] By means of the primary bypass control valve V19, a part of the coolant that has not flowed through the third aftercooler 8 is supplied to the intercooler 3 and the aftercooler 4. That is, the intercooler 3 and the aftercooler 4 are arranged or connected in series in the primary cooling circuit, but it is also specified that they are connected in parallel with each other. By means of this series connection, it is possible to obtain a higher coolant water temperature through the intercooler 3 and the aftercooler 4, and in particular, at the outlet of the primary cooling circuit 50, the outlet temperature of the coolant water at T14 is particularly high.

[0188] Regarding the embodiments of FIGS. 2 and 3, the following points should be noted. In these two embodiments, the intercooler 3 and the aftercooler 4 are connected in series to the primary cooling circuit, and in the following description, for the sake of simplicity, the primary bypass control valve V19 is not considered. Thus, both the intercooler 3 and the aftercooler 4 receive the complete coolant flow, i.e., the entire coolant flow of the primary cooling circuit 50, and the coolant flow has already flowed through the cooler, and thus, due to the series connection, has a temperature higher than the temperature T10. Thereby, a relatively high-temperature coolant can be supplied to the intercooler 3 and the aftercooler 4.

[0189] Regarding FIGS. 3 and other embodiments, the following advantages are obtained:

[0190] It is possible to achieve maximum heat recovery when the heat consumption is sufficient and operation without using coolant water. Thus, it is not necessary to use the secondary cooling system 11, but it can be kept available for cases where the required amount of heat is less or when the compressor requires better cooling.

[0191] As a use, a heating system for a connected building is proposed. This can have the following effects. In winter, all heat can be utilized through the heat exchanger 10. In contrast, in summer, the required amount of heat is less, but heat still needs to be dissipated. The heat dissipation is carried out through the primary-secondary heat exchanger 9, the secondary cooling system 11, and the valve V10.

[0192] Depending on the temperature requirements and alternatives, further waste heat utilization of about 10% - 30% is possible. The maximum utilization of waste heat is possible when the inlet temperature of water is about 5K - 10K higher.

[0193] A very high water outlet temperature T14 is possible, especially up to about 95°C.

[0194] In particular, through the primary water system having the inlet temperature T10 or the outlet temperature T14, when the volume flow rate is large, sufficient jacket cooling and oil cooling with heating water are possible.

[0195] Since the final cooler 7 obtains a large volume flow rate of low-temperature heating water, a sufficient dew point can be obtained.

[0196] Since the final cooler 8 obtains low-temperature heating water, it is also possible to lower the outlet temperature of the compressed air if necessary.

[0197] To control the compressor cooling circuit 32, also called the jacket cooling circuit, a control valve V13 and a jacket cooler pump 14 are provided. The control valve V13 and the jacket cooler pump 14 form a possible variant of the jacket cooling circuit.

[0198] Furthermore, temperatures T2 and T4 are shown in FIG. 3. Both can be, for example, 180°C. From this, it should be clear that high water outlet temperatures T11, T12, and T14 of, for example, 90°C can be easily achieved, which is impossible at the temperatures T16 and T23 shown in FIG. 1.

[0199] Figure 4 schematically shows, in a partially sectional view, a compressor 900 having a first compressor stage 901 and a second compressor stage 907. Further, Figure 5 shows an enlarged view of the first compressor stage 901. In the following, as far as the description of the first compressor stage is concerned with reference to Figure 4, Figure 5 will be additionally referred to.

[0200] Figure 4 shows mainly a dry screw compressor forming the compressor 900. The first compressor stage 901 performs the first stage of compression during operation. For this purpose, the first compressor stage 901 has a housing 902 and a coolant conduit 903 of a jacket cooler which is more clearly shown particularly by Figure 5.

[0201] A compressor screw 904 is provided to compress compressed gas, particularly compressed air, and the compressor screws 904 mesh with each other for compression. The compressor screw 904 is driven through a drive shaft 905 of the corresponding compressor stage. The second compressor stage 907 further compresses the gas compressed in the first compressor stage, particularly compressed air, and has a housing 909 provided with a coolant conduit 908 and a compressor screw 910 driven through a drive shaft 911.

[0202] Both drive shafts 905 and 911 are driven through a common drive motor 906, and for this purpose a gear device 912 is provided. The gear device 912 distributes the driving force from the drive motor to the two drive shafts 905 and 911, whereby the compressor screws 904 and 910 are driven.

[0203] The two compressor stages 901 and 907 can be cooled by jacket cooling realized using the coolant conduits 903 and 908. For this purpose, a coolant, particularly cooling water, flows through these coolant conduits 903 and 908, and the coolant can be controlled either together or individually.

Description of Reference Numerals

[0204] 1 First compressor stage 2 Second compressor stage 3 Intercooler 4 Final cooler 5 Oil cooler 6 Jacket cooler heat exchanger 7 Second final cooler 8 Third final cooler 9 Primary-secondary heat exchanger 10 Primary heat exchanger 11 Secondary heat exchanger 12 Primary coolant pump 12a External pump 12b Internal pump 13 Secondary coolant pump 14 Jacket cooler pump 20 Adsorption dryer 21 Primary circuit bypass 30 Compressor 32 Compressor cooling circuit 34 Compressed gas line 41 First jacket cooler 42 Second jacket cooler 50 Primary cooling circuit 100 Compressor unit 130 Compressor 131 First compressor stage 132 Second compressor stage 133 Intercooler 134 Final cooler 135 Oil cooler 141 First jacket cooler 142 Second jacket cooler 145 Oil circuit 150 Primary cooling circuit 151 Coolant supply section 152 Coolant return section 154 Heat sink 156 Primary heat exchanger 158 Primary coolant pump 159 Primary control valve 163 Intercooler line 164 Final cooler line 165 Oil cooler line 166 Jacket cooler line 173 Manual Intercooler Valve 174 Final Cooler Control Valve 175 Manual Oil Cooler Valve 176 Manual Jacket Cooler Valve 185 Oil Bypass Valve 300 Compressor Unit 580 Secondary Cooling Circuit 900 Compressor 901 First Compressor Stage 902 Housing 903 Coolant Conduit 904 Compressor Screw 905 Drive Shaft 906 Drive Motor 907 Second Compressor Stage 908 Coolant Conduit 909 Housing 910 Compressor Screw 911 Drive Shaft 912 Gear Unit 5800 Cooling Water Circuit M85 Pressure Dew Point Temperature T at Measurement Point Txx Control Valves V10, V11, V12, V13, V14, V16, V19, V25, V28

Claims

1. a compressor, in particular a dry screw compressor, for compressing a gas to produce a compressed gas, in particular compressed air, the compressor having at least one compressor stage; - a cooling device, A compressor device comprising: an oil cooler for cooling the oil heated by the compressor; at least one compressed gas cooler for cooling the gas compressed in whole or in part to a compressed gas; at least one housing cooler for cooling a housing or a part of a housing of the compressor, the oil cooler, at least one of the compressed gas coolers and at least one of the housing coolers are each arranged to achieve cooling by a coolant flow consisting of a liquid coolant, in particular water; at least one housing cooler control means is provided for at least one said housing cooler for individually controlling the cooling flow through said housing cooler, - a compressor arrangement having a cooling control, said cooling control being configured to operate at least one said housing cooler control means such that at least one cooling flow through at least one said housing cooler is controlled independently from the cooling flow through said oil cooler.

2. The compressor arrangement according to claim 1, characterized in that the cooling control section is arranged to operate at least one of the housing cooler control means such that at least one cooling flow through at least one of the housing coolers is controlled independently from the cooling flow through at least one of the compressed gas coolers.

3. 3. A compressor arrangement according to claim 1 or 2, characterized in that the cooling control is arranged so that for at least one of the housing coolers only the cooling flow is controlled individually, in particular by the housing cooler control means, and for the oil cooler and the at least one of the compressed gas coolers the cooling flow is not controlled or is only controlled through a common control of the overall coolant flow.

4. the compressor has at least one rotor for compressing a compressed gas, at least one compressor gap is formed between a housing and at least one said rotor or between two said rotors, said compressor gap having a variable gap thickness, A compressor arrangement according to any one of claims 1 to 3, characterized in that the cooling control is configured to operate at least one of the housing cooler control means such that the gap thickness remains within a predeterminable range and / or such that the gap thickness complies with a predeterminable target gap thickness.

5. The cooling control unit, The compressor gap thickness is detected and / or estimated, A compressor arrangement according to any one of claims 1 to 4, characterised in that at least one of said housing cooler control means is set to be controlled in dependence on the detected or estimated gap thickness.

6. The cooling control unit, at least one outlet temperature of the gas, fully or partially compressed into compressed gas, is detected as it leaves at least one compressor stage; a setpoint temperature value is determined for the outlet temperature at which an optimal gap thickness is expected, said setpoint temperature value being determined in particular during operation; A compressor arrangement according to any one of claims 1 to 5, characterized in that at least one of the housing cooler control means is set to be controlled so that the outlet temperature complies with the set temperature value, in particular so that the outlet temperature is regulated to the set temperature value as a target temperature.

7. The cooling control unit, at least one of said housing cooler control means is controlled in dependence on at least one coolant temperature, in particular the coolant temperature sensed at the coolant outlet of the housing cooler, and - the coolant temperature detected downstream of the housing cooler.

8. a compressor for compressing the gas to produce a compressed gas, in particular compressed air; - a cooling device, A compressor device comprising: an oil cooler for cooling the oil heated by the compressor; at least one compressed gas cooler for cooling the gas compressed in whole or in part to a compressed gas; at least one housing cooler for cooling a housing or a part of a housing of the compressor, the oil cooler, at least one of the compressed gas coolers and at least one of the housing coolers are each arranged to achieve cooling by a coolant flow consisting of a liquid coolant, in particular water; - a compressor arrangement according to any one of claims 1 to 7, in particular wherein the oil cooler and / or at least one of the at least one housing cooler is connected in series with at least one compressed gas cooler of the at least one compressed gas cooler, whereby the coolant flow passes through the series-connected coolers one after the other.

9. - the coolant flow through the series-connected coolers first passes through the oil cooler, 9. The compressor arrangement according to claim 8, characterized in that the oil cooler is provided with a coolant having a lower temperature than the at least one compressed gas cooler, since the coolant then flows through the at least one compressed gas cooler.

10. a cooling circuit is provided for supplying the coolant at a cooling circuit inlet and for taking off the coolant heated by the cooler at a cooling circuit outlet in order to cool the heated coolant again or to supply it for further use, in particular to utilize the heat of the coolant; The compressor device has a cooling control unit, and the cooling control unit controls the compressor device to: A compressor arrangement according to claim 8 or 9, characterized in that it is set up to control the coolant at the cooling circuit outlet to have a temperature between 85°C and 95°C, in particular between 90°C and 95°C.

11. - a plurality of compressed gas coolers are provided, Compressor arrangement according to any one of claims 8 to 10, characterized in that the compressor arrangement is configured in such a way that the coolant, after having flowed through an oil cooler, flows through several compressed gas coolers, in particular connected in parallel, whereby the coolant flows through several of the compressed gas coolers in parallel.

12. - the plurality of compressed gas coolers is divided into a plurality of compressed gas cooler groups, the compressed gas coolers of each of said compressed gas cooler groups are connected in parallel with each other, said compressed gas coolers are connected in series with one another, in particular the first compressed gas cooler and the second compressed gas cooler are connected in parallel to each other, A compressor arrangement according to any one of claims 8 to 11, characterised in that it is connected in series with a third compressed gas cooler and a fourth compressed gas cooler connected in parallel with each other.

13. a compressor, in particular a dry screw compressor, for compressing a gas to produce a compressed gas, in particular compressed air, the compressor having at least one compressor stage; - a cooling device, 1. A method for controlling a compressor unit comprising: an oil cooler for cooling the oil heated by the compressor; at least one compressed gas cooler for cooling the gas compressed in whole or in part to a compressed gas; at least one housing cooler for cooling a housing or a part of a housing of the compressor, the oil cooler, at least one of the compressed gas coolers and at least one of the housing coolers are each arranged to achieve cooling by a coolant flow consisting of a liquid coolant, in particular water; at least one housing cooler control means is provided for at least one said housing cooler for individually controlling the cooling flow through said housing cooler, - the compressor arrangement has a cooling control, the cooling control operating at least one said housing cooler control means such that at least one cooling flow through at least one said housing cooler is controlled independently from the cooling flow through the oil cooler.

14. 14. Method according to claim 13, characterized in that a compressor arrangement according to any one of claims 1 to 12 is used.

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

16. the compressor has at least one rotor for compressing a compressed gas, at least one compressor gap is formed between a housing and the at least one rotor, the compressor gap having a variable gap thickness; A method according to any one of claims 13 to 15, characterized in that the cooling control unit operates at least one of the housing cooler control means such that the gap thickness remains within a predeterminable range and / or such that the gap thickness complies with a predeterminable target gap thickness.

17. Using the cooling control unit, The compressor gap thickness is detected and / or estimated, Method according to any one of claims 13 to 16, characterised in that at least one housing cooler control means is controlled in dependence on the detected or estimated gap thickness.

18. Using the cooling control unit, at least one outlet temperature of the gas, fully or partially compressed into compressed gas, is detected as it leaves at least one compressor stage; a setpoint temperature value is determined for the outlet temperature at which an optimal gap thickness is expected, said setpoint temperature value being determined in particular during operation; A method according to any one of claims 13 to 17, characterized in that at least one of the housing cooler control means is controlled such that the outlet temperature complies with the set temperature value, in particular such that the outlet temperature is regulated to the set temperature value as a target temperature.

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