Method for controlling a first reference temperature of a device for compressing a gas

Abstract

A method for controlling a first reference temperature in an apparatus (1) for compressing a gas, the apparatus (1) comprising: an oil-injected element (2) for compressing the gas; and an oil injection pipe network (6) for injecting oil into the oil-injected element (2); the oil injection pipe network (6) comprising distribution means (8) for distributing oil to a first part and a second part; an oil cooler (10) cooled by a fan (9) for cooling the first part; and a bypass (11) for bypassing the second part over the oil cooler (10); wherein first a distribution rate of the first part is controlled to a required distribution rate, and then a speed of the fan (9) is controlled to a required speed, optionally based on the distribution rate, the distribution rate being controlled by a control unit (15) based on a non-fuzzy logic algorithm.

Description

[Technical Field]

[0001] The present invention relates to a method for controlling a first reference temperature of a device for compressing gas to a desired temperature value.

[0002] In this specification, "gas compressing apparatus" may refer to both a compressor apparatus for compressing atmospheric gases to superatmospheric pressure, and a vacuum pump apparatus for drawing a vacuum in a user network or enclosed space.

[0003] More particularly, the present invention relates to a method for controlling a first reference temperature of an apparatus to a first desired temperature value, the apparatus comprising the following components: an oil-filled element for compressing the gas; an oil injection pipe network having outlets for injecting oil into the oil-injected elements; The oil injection pipe network is - distribution means for distributing oil between the first and second portions; a fan-cooled oil cooler for cooling the first part; a bypass for routing the second portion past the oil cooler; First, the distribution rate of the first portion is controlled to a distribution rate required to bring a second reference temperature of the device to a second desired temperature value, and then the speed of the fan is controlled to a speed required to bring the first reference temperature to the first desired temperature value.

[0004] In this specification, "reference temperature of the device" means the temperature at a specific reference location of the device, for example the temperature at the outlet of an oil-injected element where the gas temperature of the device is usually highest, or the temperature at the outlet of an oil-injected pipe network where the oil temperature is important for cooling and lubrication of the device.

[0005] In this specification, the "distribution ratio of the first portion" means the ratio of the flow rate or amount of the first portion to the total flow rate or amount of oil, and therefore, this distribution ratio can range from 0 to 100%. [Background technology]

[0006] The need and method for controlling a particular reference temperature of a gas compressing device to a desired temperature value is already known.

[0007] On the one hand, the reference temperature must not fall below a minimum level, for example, to avoid the formation of condensate from the gas, which would adversely affect the cooling or lubricating capacity of the oil in the device and further lead to corrosion of the device's components, resulting in a shortened service life.On the other hand, the reference temperature may not be higher than a maximum level, for example, to avoid damage to the device due to deterioration of the oil in the device or deformation of the components in the device.

[0008] an oil-injected element for compressing the gas and an oil-injection pipe network for injecting oil into the oil-injected element; of In some existing systems, the base temperature is controlled to the desired temperature using a thermostatic control valve with a fixed temperature setpoint and a fixed speed fan to cool the oil in the oil injection pipe network, and the fan shuts off when the base temperature falls below a maximum level.

[0009] Tests have shown that devices using thermostatically controlled valves with fixed setpoints and fixed-speed fans are not necessarily energy-efficient. Even if the reference temperature does not significantly exceed the maximum level, the fan is always started at a fixed speed, causing the reference temperature to drop rapidly and forcing the fan to be stopped quickly. In the worst case scenario, the reference temperature may drop so much that it falls below the minimum level, increasing the risk of condensation forming inside the device.

[0010] Other existing devices use thermostatically controlled valves and variable speed fans controlled by PID controllers. Such systems typically have separate control circuits for controlling the thermostatically controlled valve and the fan.

[0011] Tests have shown that such devices can exhibit erratic and oscillatory behavior due to interference between separate control circuits, the adverse effects of which include possible shutdown of the device, damage to mechanical components of the device, and premature wear of various components of the device.

[0012] WO 2018 / 033827 describes a method for controlling the outlet temperature of an apparatus having an oil-injected element for compressing gas and an oil injection pipe network for injecting oil into the oil-injected element, wherein the position of a thermostatic control valve is controlled by applying a fuzzy logic algorithm to measurements of the outlet temperature, and the speed of a fan for cooling the oil is controlled by applying the fuzzy logic algorithm and further based on the position of the thermostatic control valve.

[0013] The drawback of using a fuzzy logic algorithm is that it is a complex "multiple-input-multiple-output" (MIMO) computational algorithm. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2018 / 033827 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention aims to overcome at least one of the above and / or other disadvantages.

[0016] More specifically, the object of the present invention is to provide a simple method for controlling the reference temperature of a device for compressing gas to a desired temperature value, which, on the one hand, uses as many separate sub-circuits as possible with the simplest possible calculation algorithms, but, on the other hand, also minimizes as much interference as possible between the separate control circuits within the device. [Means for solving the problem]

[0017] To this end, the invention relates to a method for controlling a first reference temperature of a gas compression device to a desired temperature value, the device comprising the following components: an oil-injected element for aspirating gas at an inlet of the device and compressing the gas to a working pressure at an outlet of the oil-injected element; an oil injection pipe network having outlets for injecting oil into the oil-injected elements; The oil injection pipe network is - distribution means for distributing oil between the first and second portions; a fan-cooled oil cooler for cooling the first part; a bypass for routing the second portion past the oil cooler; Equipped with First, - determining a required dispensing rate of the first portion to bring a second reference temperature of the device to a second desired temperature value; - the distribution rate of the first portion is controlled to a desired distribution rate; after that - a required speed of the fan is determined to bring the first reference temperature to a first desired temperature value, and if the first reference temperature is the same as a second reference temperature, the required speed is determined based on the second desired temperature value and a distribution ratio; -The fan speed is controlled to the required speed, The distribution ratio is determined by the control unit. - Second reference temperature of 1st the current value, and - a second desired temperature value, is used as input and is controlled based on a non-fuzzy logic algorithm.

[0018] The advantage of this is that the distribution rate is controlled by a standard controller, such as a PID controller or an ON / OFF controller, thereby avoiding the use of complex "multiple input-multiple output" calculation algorithms such as those described in WO 2018 / 033827.

[0019] Nevertheless, the device according to the invention has the same basic advantages as described in WO 2018 / 033827.

[0020] More specifically, if the first reference temperature is the same as the second reference temperature, the method according to the invention also avoids any interference between the control of the distribution ratio and the control of the fan speed, in stark contrast to the risk of this type of interference that is strictly warned about in the case of devices using SISO control units for the control of the distribution ratio and the control of the variable speed fan on page 2, lines 18-27 of WO 2018 / 033827.

[0021] In a preferred embodiment of the method according to the invention, the second desired temperature value is determined based on the maximum temperature value within a group of one or more temperature values.

[0022] As a result, the second desired temperature value can be determined based on any number of desired purposes.

[0023] Furthermore, the second desired temperature value can be adjusted to the most relevant purpose depending on the operating area of ​​the device.

[0024] In a more preferred embodiment of the method according to the invention, the first temperature value in the group is such that the temperature of the compressed gas at the outlet is: the first condensation temperature of the compressed gas at the outlet, or - a first condensation temperature plus a first safety margin; represents the value of the second reference temperature, which is equal to

[0025] In this way, when the second desired temperature value is determined, the first objective is taken into account in terms of avoiding the formation of condensate in the device.

[0026] Preferably, the first temperature value is limited in this respect according to a first temperature interval between a first minimum temperature limit value and a first maximum temperature limit value.

[0027] this is, - if the first temperature value is lower than the first minimum temperature limit, the first temperature value is set equal to the first minimum temperature limit; If the first temperature value is higher than the first maximum temperature limit, the first temperature value is set equal to the first maximum temperature limit; - if the first temperature value is in a first temperature interval between a first minimum temperature limit and a first maximum temperature limit, the first temperature value is not changed; This means that...

[0028] By limiting the first temperature value to a first temperature interval, safety constraints can be taken into account, for example with respect to minimum and maximum operating temperatures of the device.

[0029] In a further preferred embodiment of the method according to the invention, the second temperature value in the group represents a second reference temperature value at which the specific energy demand of the device is minimum.

[0030] In this way, when the second desired temperature value is determined, the second objective is taken into account in terms of minimizing the specific energy requirements and, consequently, maximizing the energy efficiency of the device.

[0031] Preferably, the second temperature value is at least - Operating pressure Sudai 2 the current value, and - the third, which represents the gas temperature at the inlet the current value, is determined based on the

[0032] In the context of the present invention, certain parameters are referred to as "representing" the current "Value" does not necessarily mean the current does not mean that the value is equal to the value of this parameter, but rather the current This means that the value can be derived from the value of this parameter.

[0033] In this way, the second temperature value is determined based on two standard state variables of the device, the values ​​of which can be reliably and easily measured using accurate, relatively inexpensive and readily available sensors.

[0034] More preferably, the oil injected element is a variable speed degree If driven by a motor, the second temperature value is a tenth value representing the rotational speed of a variable speed motor. the current Further determinations are made based on the value.

[0035] As a result, the rotational speed of the variable speed motor, and consequently the variable power supplied by the variable speed motor to the gas compression process, is taken into account when determining the second temperature value.

[0036] Furthermore, the second temperature value is alternatively or additionally preferably limited according to a second temperature interval between a second minimum temperature limit value and a second maximum temperature limit value.

[0037] this is, - if the second temperature value is lower than the second minimum temperature limit, the second temperature value is set equal to the second minimum temperature limit; - if the second temperature value is higher than the second maximum temperature limit, the second temperature value is set equal to the second maximum temperature limit; - if the second temperature value is in a second temperature interval between a second minimum temperature limit and a second maximum temperature limit, the second temperature value is not changed; This means that...

[0038] By limiting the second temperature value to a second temperature interval, safety constraints can be taken into account, for example with respect to minimum and maximum operating temperatures of the device.

[0039] In a further preferred embodiment of the method according to the invention, the second reference temperature is controlled from the old temperature value to a second desired temperature value; and To determine the second desired temperature value, the maximum temperature value is calculated by subtracting the maximum temperature decrease value from the old temperature value, and by subtracting the maximum temperature increase value from the old temperature value. value plus a third temperature interval between the temperature

[0040] In this way, the change in the second reference temperature can be limited when the second reference temperature is controlled to a second desired temperature value, for example to take into account safety constraints related to temperature changes within the device.

[0041] Preferably, the second reference temperature is controlled from the old temperature value to the second desired temperature value in a preset time interval, and the maximum temperature decrease value and the maximum temperature increase value are positively dependent on the length of the preset time interval.

[0042] In this way, the change in the second reference temperature can be limited according to a preset time interval, for example to take into account safety constraints related to maximum absolute temperature time gradients in the device.

[0043] In a further preferred embodiment of the method according to the invention, the required distribution ratio is the current The desired temperature is determined based on a first ratio between the temperature and a second desired temperature value.

[0044] This first ratio is the ratio of the second desired temperature value to the first the current It is a measure of the deviation of values.

[0045] If the first ratio is less than 1, this indicates that the value of the second reference temperature is too low, and the requested distribution ratio should be selected to be lower than the current value of the distribution ratio if possible; in such a case, less oil will be sent to the oil cooler, which will result in less cooling of the injected oil and an increase in the second reference temperature.

[0046] If the first ratio is greater than 1, this indicates that the value of the second reference temperature is too high, and the requested distribution ratio should be selected to be higher than the current value of the distribution ratio. In such a case, more oil will be sent to the oil cooler, resulting in more cooled injected oil and a decrease in the second reference temperature.

[0047] Preferably, the requested distribution percentage depends on the first ratio according to a first monotonically increasing function between a minimum value of zero and a maximum value of 100%.

[0048] In this way, the change in the dispense rate relative to the requested dispense rate will not be small if there is a large deviation between the second reference temperature and the second desired temperature value.

[0049] Alternatively, and preferably, the desired distribution ratio is: -First the current The value is - higher than a second desired temperature value or a second desired temperature value plus a second safety margin, or - during the first time period, the temperature is higher than a second desired temperature value or the second desired temperature value plus a second safety margin; The maximum value is 100%. - Otherwise, it is the minimum zero value.

[0050] This is a simple ON / OFF control, and if the reference temperature is likely to be too high, more specifically, if it is higher than a second desired temperature value or the second desired temperature value plus a second safety margin, all oil is sent to the oil cooler.

[0051] By applying the first period before controlling the distribution rate to a state where all oil is sent to the oil cooler, it is possible to avoid a rapid and unnecessary change in the distribution rate from a minimum of zero to a maximum of 100% and back to zero, which would otherwise occur if the second reference temperature were higher than the second desired temperature or the second desired temperature plus a second safety margin for a limited, harmless period shorter than the first period.

[0052] Thus, by applying the first period, the control dynamics of the distribution means and the device generally do not react or react less to harmless short-term increases in the second reference temperature, and as a result, the control dynamics are more stable than if the first period were not applied.

[0053] In a further preferred embodiment of the method according to the invention, the second reference temperature is is the temperature of the gas at the outlet of the oil-injected element, or - the temperature of the oil at the outlet of the oil injection pipe network.

[0054] The outlet of the oil-injected element is where the gas pressure in the device is highest. As a result, the risk of condensation formation is also highest at this outlet. The higher the gas pressure, the higher the condensation temperature of the gas. It is necessary to ensure that the temperature of the gas at the outlet does not fall below the condensation temperature of the gas at this outlet. The temperature of the gas at the outlet of the oil-injected element is therefore the relevant second reference temperature in the device in order to avoid the formation of condensation in the device.

[0055] The temperature of the oil at the outlet of the oil injection pipe network determines the cooling capacity of the oil. It is necessary to ensure that this cooling capacity is not too high, in order to prevent the temperature of the gas at a given location in the device from falling below the condensation temperature of the gas at this location. The temperature of the oil at the outlet of the oil injection pipe network is therefore a relevant second reference temperature in the device, also with the aim of avoiding the formation of condensate in the device.

[0056] In a further preferred embodiment of the method according to the invention, the required fan speed is determined based on a maximum speed value from a set of one or more speed values.

[0057] This allows the required speed to be determined based on any number of criteria desired.

[0058] Furthermore, the required speed can be adjusted to the most relevant criteria depending on the operating area of ​​the device.

[0059] In a more preferred embodiment of the method according to the invention, the first speed value in said set is of Represents the value of the fan speed required to achieve the second desired temperature value.

[0060] In this way, the first criterion is considered in determining the required fan speed with respect to achieving the second desired temperature value. In other words, fan control in this respect has the same objective as the distribution ratio control described above, and thus helps achieve the distribution ratio control goal.

[0061] In a further preferred embodiment of the method according to the invention, - Second reference temperature of Fourth the current If the value is higher than the preset minimum temperature, and -Distribution ratio of Fifth the current If the value is higher than the preset minimum allocation percentage, the current If the value is higher than the desired temperature value, The first velocity value is at least: -6th, which represents the operating pressure the current value, and - the seventh, which represents the gas temperature at the inlet the current value, is determined based on the

[0062] In this way, the first speed value is determined based on two standard state variables of the device, the values ​​of which can be reliably and easily measured using accurate, relatively inexpensive and readily available sensors.

[0063] Preferably, if the oil-injected element is driven by a variable speed motor, the first speed value is an eleventh value representing the rotational speed of the variable speed motor. the current Further determinations are made based on the value.

[0064] As a result, the rotational speed of the variable speed motor, and consequently the variable power supplied by the variable speed motor to the gas compression process, is taken into account when determining the first speed value.

[0065] Alternatively or additionally, preferably -Fourth the current if the value is greater than the second desired temperature value plus the first tolerance value, or - In the second period, the fourth the current if the value is greater than the second desired temperature value plus the first tolerance value, or -Fourth the current if the value is less than a second desired temperature value minus a second tolerance; or - In the third period, the fourth the current If the value is less than the second desired temperature value minus the second tolerance value, The first velocity value is at least -Distribution ratio of Fifth the current value, and -Fourth the current a second ratio between the value and a second desired temperature value; The determination will be further based on the

[0066] Distribution ratio of Fifth the current By determining the first speed value based on the value, the distribution ratio can be taken into account when determining the fan speed, and therefore any interference between the fan speed control and the distribution ratio control can be avoided.

[0067] The second ratio is the fourth the current is a measure of the deviation of the first desired temperature value from the second desired temperature value.

[0068] If the second ratio is less than 1, this indicates that the value of the second reference temperature is too low, and the requested distribution ratio should be selected to be lower than the current value of the distribution ratio, in which case less oil will be sent to the oil cooler, resulting in less cooling of the injected oil and an increase in the second reference temperature.

[0069] If the second ratio is greater than 1, this indicates that the value of the second reference temperature is too high, and the requested distribution ratio should be selected to be higher than the current value of the distribution ratio. In such a case, more oil will be sent to the oil cooler, resulting in more cooled injected oil and a decrease in the second reference temperature.

[0070] More preferably, the first speed value depends on the second ratio according to a second monotonically increasing function.

[0071] In this way, when there is a large deviation between the second reference temperature and the second desired temperature value, the change in fan speed relative to the first speed value will not be small.

[0072] Alternatively or additionally, more preferably, the first velocity value is increased by a fifth velocity value according to a third monotonically increasing function. the current Depends on the value.

[0073] As a result, when controlled to the first speed value, the fan speed will not become smaller when the distribution ratio increases, and will not become larger when the distribution ratio decreases.

[0074] This is advantageous for the stability of fan speed control, since it allows the fan speed to be gradually increased as the distribution percentage increases and gradually decreased as the distribution percentage decreases, thereby preventing the fan from having to suddenly start up from a stopped state at high speed when the distribution percentage increases from a zero value, or from suddenly going from high speed to a stopped state when the distribution percentage suddenly drops to a zero value.

[0075] In a further preferred embodiment, if the device comprises an aftercooler for cooling the compressed gas downstream of the oil-injected element, -Minimum effective temperature in aftercooler of 8th the current The value is the minimum effective temperature required. of The second speed value in the set, if higher than the a first velocity value, and -8th the current a third ratio between the value and the value of the required minimum effective temperature; is determined based on Otherwise, the second speed value is set equal to zero.

[0076] In this way, the minimum effective temperature of the aftercooler of 8th the current If the value is too high, the fan speed can be controlled to a second speed value higher than the first speed value, so that the fan is utilized to sufficiently cool the aftercooler in addition to cooling the oil cooler, and the maximum temperature of the gas in the aftercooler can be controlled and limited to the minimum required effective temperature.

[0077] Preferably, the required minimum effective temperature is equal to the second condensation temperature of the aftercooler gas plus an offset.

[0078] The formation of condensate in the aftercooler can be avoided by offsetting.

[0079] Alternatively or additionally, the second speed value preferably depends on the third ratio according to a fourth monotonically increasing function.

[0080] In that case, the minimum effective temperature required of If there is a large deviation of the minimum effective temperature beyond the value, the second speed value will not be decreased and the minimum effective temperature will be the minimum effective temperature required at the accelerated speed. of It is not possible to deviate further from the value.

[0081] In a further preferred embodiment of the method according to the invention, the third speed value in the set is: -First reference temperature of 9th the current value, and -First reference temperature of A preset maximum value, and the third velocity value is determined based on -9th the current If the value is lower than the preset maximum, it is equal to zero, and -9th the current If the value is higher than the preset maximum, it is equal to the value representing the maximum speed of the fan.

[0082] In this way, the fan speed can be adjusted to a third speed value determined by exceeding a preset maximum value, this preset maximum value being, for example, a maximum value of a first reference temperature of a gas above which the first reference temperature must not rise for safety reasons.

[0083] The present invention further provides a method for carrying out a method according to any of the above-described embodiments, comprising: a first computing control unit, comprising a control unit for controlling a second reference temperature in the device for compressing gas to a second desired temperature value; a second computing and control unit for controlling a first reference temperature of the device to a first desired temperature value; The present invention relates to a computer-controlled assembly comprising:

[0084] Finally, the invention relates to a device for compressing gas, comprising such a computer-controlled assembly according to the invention.

[0085] It is clear that such a computer-controlled assembly and such an apparatus offer the same advantages as the method according to the embodiment of the invention described above.

[0086] In order to better explain the characteristics of the present invention, several preferred embodiments of the method, computer-controlled assembly and device according to the invention will now be described by way of example and not of limitation with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0087] [Figure 1] 1 shows an apparatus with a computer-controlled assembly according to the present invention; [Figure 2] 1 shows a schematic overview of the method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0088] FIG. 1 shows a device 1 for compressing a gas, which device 1 comprises an oil-filled element 2 for drawing in gas at an inlet 3 of the device 1 and compressing this gas at its outlet 4 to a working pressure.

[0089] Within the scope of the present invention, the device 1 is understood as a complete compressor or vacuum pump installation, including in particular an oil-injected element 2 in the form of a compressor or vacuum pump element, respectively, all typical connecting pipes and valves, a possible housing of the device 1, and a motor 5 for driving the oil-injected element 2.

[0090] In the context of the present invention, an oil-filled element 2 is understood as an element housing in which gas is compressed by the movement of a rotating rotor or a reciprocating piston.

[0091] In this regard, by way of non-limiting example, the oil injected element 2 may comprise one or more screw rotors, gear rotors, baffles, lobes or pistons.

[0092] If the device 1 comprises a compressor element, the inlet 3 of the device 1 is typically fluidly connected to the atmospheric environment of the device 1. If the device 1 comprises a vacuum pump element, the inlet 3 is typically fluidly connected to a user network or an enclosed space at sub-atmospheric pressure.

[0093] Furthermore, the device 1 comprises an oil injection pipe network 6 having an outlet 7 for injecting oil into the oil-injected element 2 .

[0094] In this respect, it is not excluded within the scope of the present invention that the oil-injection pipe network 6 comprises a plurality of outlets 7 for injecting oil into the oil-injected element 2 .

[0095] Compression of the gas in the oil-injected element 2 generates heat of compression, which heats the gas. In order to keep the temperature of the compressed gas at the outlet 4 of the oil-injected element 2 below a certain maximum safety limit, the temperature of the injected oil must be below a maximum level corresponding to this safety limit. On the other hand, the temperature of the compressed gas at the outlet 4 must not fall below a first condensation temperature of the gas at the outlet 4 or below a temperature equal to the first condensation temperature plus a first safety margin, in order to avoid the formation of condensate at the outlet 4. Consequently, the temperature of the injected oil must be above a minimum level corresponding to this first condensation temperature or this first condensation temperature plus a first safety margin. Therefore, the temperature of the gas at the outlet 4 of the oil-injected element 2, and accordingly the temperature of the oil at the outlet 7 of the oil-injection pipe network 6, must be controlled at both ends to values ​​within a correspondingly limited temperature interval.

[0096] For this purpose, the oil injection pipe network 6 distribution means 8, such as a thermostatically controlled valve, for distributing the oil between the first and second portions; an oil cooler 10 cooled by a fan 9 for cooling the first part; a bypass 11 for bypassing the second part beyond the oil cooler 10; Equipped with.

[0097] The speed of the fan 9 is variable and is driven by a second motor 12. This makes it possible, for example, to control the cooling of the first portion of oil to be injected by adjusting the speed of the fan 9.

[0098] More generally, in the present invention, the speed of the fan 9 is adjusted so that a first reference temperature of the device 1 is controlled to a first desired temperature value.

[0099] The distribution means 8 and the bypass 11 are provided for diverting the second part of the injected oil beyond the oil cooler 10, thus controlling the distribution rate of the first part of the oil and thereby more or less limiting the cooling of the injected oil by the oil cooler 10. In this way, the second reference temperature of the device 1 can be controlled to a second desired temperature value, for example the temperature of the compressed gas at the outlet 4 of the oil-injected element 2 or the temperature of the oil at the outlet 7 of the oil-injection pipe network 6. The first reference temperature controlled by the fan 9 can be the same as the second reference temperature, in which case the first desired temperature value is equal to the second desired temperature value.

[0100] To control the distribution rate, the device 1 performance The first computer includes a calculation control unit 13. performance The calculation control unit 13 a calculation unit 14 for determining a second desired temperature value; - Second reference temperature of a control unit (15) for adjusting the distribution ratio of the first portion to the second desired temperature based on the first current value; Equipped with.

[0101] In this case, the control unit 15 is designed, for example, as a PID controller or an ON / OFF controller.

[0102] In this case, the second reference temperature of 1st the current The value is provided by measurement with a temperature sensor, for example a first temperature sensor 16 at the outlet 4 of the oil-injected element 2 or a second temperature sensor 17 at the outlet 7 of the oil-injection pipe network 6 .

[0103] The second desired temperature value comprises at least: - A second indicator showing the operating pressure the current value (this second the current The value is provided, for example, by measurement using a first pressure sensor 18 at the outlet 4 of the oil-injected element 2), and - a third temperature indicating the temperature of the gas at inlet 3 the current value (this third the current the value is provided, for example, by measurement using a third temperature sensor 19 at the inlet 3 of the device 1), is determined by the calculation unit 14 based on

[0104] In addition, it is also possible to take into account a measurement of the atmospheric pressure at the inlet 3, which is provided, for example, by a measurement with a second pressure sensor 20 at the inlet 3 of the device 1. However, the absolute standard value of atmospheric pressure can also simply be assumed to be 1 bar or 1 atmosphere, which means that this measurement of atmospheric pressure, and thus the second pressure sensor 20, is not strictly necessary for the invention.

[0105] Likewise, it is also possible to consider measuring the relative humidity at the inlet 3, for example using the humidity sensor 21 at the inlet 3. Alternatively, a worst-case relative humidity value of 100% can be assumed for this gas at the inlet 3. In the latter case, the measurement of the relative humidity at the inlet 3, and thus the humidity sensor 21, is not strictly necessary for the invention.

[0106] a second desired temperature value determined by the calculation unit 14; and a second desired temperature value of Based on the first current value, the control unit 15 determines a desired distribution rate and controls the distribution rate of the first portion of oil to this desired distribution rate.

[0107] 1, the distribution means 8 is arranged downstream of the oil cooler 10 and the bypass 11. However, in the context of the present invention, it is not excluded that the distribution means 8 is arranged upstream of the oil cooler 10 and / or the bypass 11, for example at the point where the piping to the oil cooler 10 and the bypass 11 branch off from each other.

[0108] To control the speed of the fan 9 , the device 1 comprises a second arithmetic and control unit 22 .

[0109] The second computing and control unit 22 together with the first computing and control unit 13 form a computing and control assembly according to the present invention.

[0110] The control of the fan 9 can have the purpose of controlling the second reference temperature to a second desired temperature value, similar to the control of the distribution rate of the first oil portion already mentioned above, in which case the first reference temperature will be the same as the second reference temperature and the first desired temperature value will be equal to the second desired temperature value.

[0111] In that case, the second reference temperature of Fourth the current the value is greater than the second desired temperature value, and the distribution ratio of Fifth the current If the value is higher than the preset minimum distribution rate, then the second arithmetic and control unit 22 performs at least -6th indicator showing operating pressure the current Value (6th the current The value is provided, for example, by measurement with a first pressure sensor 18 at the outlet 4 of the oil-injected element 2), and - the seventh temperature of the gas at the inlet 3 the current Value (7th the current The value is provided, for example, by measurement using a third temperature sensor 19), The required speed of the fan 9 is determined based on the

[0112] Fourth the currentThe value may be provided by measurement using the first temperature sensor 16 or the second temperature sensor 17, for example.

[0113] The second desired temperature value is calculated by the second calculation and control unit 22. total This is obtained from calculation unit 14.

[0114] Next, in order to be able to take into account the distribution rate of the first portion of oil when controlling the speed of the fan 9, the required speed of the fan 9 is of To determine the specific value, of Fifth the current This fifth value can also be considered. the current The value can be provided by measuring the position of the distributor 8 or by using the flow sensor 23, which allows to measure the opening of the distributor 8 and thus the distribution rate of the first portion of oil.

[0115] Of course, in the context of the present invention, the second arithmetic and control unit 22 receives the fifth the current It is also possible to obtain a value, in which case the position sensor or flow sensor 23 is no longer necessary and can be omitted.

[0116] FIG. 1 also shows that the gas compressed by the oil-injected element 2 can be passed, for example, through an oil separator 24, where the compressed gas is purified by separating the oil previously injected into the oil-injected element 2 from the compressed gas before the resulting purified compressed gas exits the apparatus 1.

[0117] The oil separated in a possible oil separator 24 is in this case preferably re-injected into the oil-injected element 2 via the oil-injection pipe network 6 .

[0118] Optionally, the compressed gas, whether purified or not, can be sent to an aftercooler 25 before leaving the device 1. In this aftercooler 25, the compressed gas can be cooled by the same fan 9 as used in the oil cooler 10. In that case, the speed of the fan 9 can be controlled so that the minimum effective temperature of the gas in the aftercooler 25 is below the required minimum effective temperature. In this case, the first reference temperature is equal to the minimum effective temperature of the gas in the aftercooler 25. The fan 9 is controlled to reduce the required minimum effective temperature and the minimum effective temperature. of 8th the current This 8th value is controlled based on the current The value is measured, for example, by means of a fourth temperature sensor 26 located at a suitable position in the aftercooler 25 .

[0119] The speed of the fan 9 may also be adjusted to a first reference temperature, for example, at locations within the device 1 where temperatures are generally relatively high and need to be kept below a maximum value for safety reasons. of The control can also be based on a preset maximum value. Here, the first reference temperature is, for example, the temperature of the motor 5, the second motor 12, or the frequency converter of the device 1. The first reference temperature can also be the temperature of the gas leaving the aftercooler 25.

[0120] The speed of the fan 9 is then determined based on the first reference temperature as an input. of 9th the current This ninth value is controlled using the current The value is measured, for example, using the fifth temperature sensor 27.

[0121] In the context of the present invention, it is not impossible that this fifth temperature sensor 27 coincides with the first temperature sensor 16 or the second temperature sensor 17, for example.

[0122] If the motor 5 is a variable speed motor, calculation The unit 14 determines the second desired temperature by using a tenth parameter indicating the rotation speed of the motor 5. the currentThe second arithmetic and control unit 22 may also take into account the eleventh value indicating the rotational speed of the motor 5 when determining the required speed of the fan 9. the current The value can also be taken into account.

[0123] FIG. 2 shows a schematic overview of the method according to the invention.

[0124] As mentioned above, the second reference temperature of The second desired temperature value is determined in the calculation unit 14 .

[0125] In this case, the second desired temperature value is determined based on the maximum temperature value within the group of two temperature values, which is shown in Figure 2 by the first maximization operator MAX1.

[0126] Therefore, the first temperature value T1 in the group represents a second reference temperature value at which the temperature of the compressed gas at the outlet 4 of the oil-injected element 2 is equal to a first condensation temperature of the compressed gas at the outlet 4 of the oil-injected element 2 or this first condensation temperature plus a first safety margin.

[0127] The first condensation temperature can be determined in a manner known to those skilled in the art, for example as described in WO 2018 / 033827.

[0128] When determining the first temperature value, a value T representing the first condensing temperature with or without a first safety margin is selected. cond is again the first minimum temperature limit T min,1 and the first maximum temperature limit T max,1 The limiting of this first condensing temperature plus or without a first safety margin is performed by a first limiting operator LIM1.

[0129] If the second reference temperature is the temperature of the gas at the outlet 4 of the oil-injected element 2, then the first minimum temperature limit T min,1 and the first maximum temperature limit T max,1The value of may vary between, for example, 0°C and 120°C, and this value may be set with an accuracy of, for example, 1°C.

[0130] The second temperature value in the group is the second reference temperature value T at which the specific energy requirement of the device 1 is minimized. SER Represents.

[0131] If the motor 5 is a fixed speed motor, this second reference temperature value T SER is the second, which represents the operating pressure. the current value α2 and a third value representing the temperature of the gas at inlet 3 the current Based on the value α3, it can be calculated, for example, according to the following formula: T SER =B·α3+C·α2+D (Equation 1)

[0132] If the motor 5 is a variable speed motor, this second reference temperature value T SER is the second, which represents the operating pressure. the current A third value α2 represents the temperature of the gas at the inlet 3. the current value α3, and a tenth value representing the rotation speed of the motor 5 the current Value α 10 Based on this, it can be calculated, for example, according to the following formula: T SER =A·α 10 +B·α3+C·α2+D (Equation 2)

[0133] where: the current Value α 10 is the value of the rotational speed of the motor 5 determined as a percentage of the maximum rotational speed of the motor 5.

[0134] In the above equations 1 and 2, the value of the second reference temperature T SER is expressed in °C, and the second the current The value α2 is determined as the operating pressure in bar and the third the current The value α3 is determined as the temperature of the gas at the inlet 3 in °C.

[0135] If the second reference temperature is the temperature of the gas at the outlet 4 of the oil-injected element 2, the possible value intervals for the constants A, B, C and D in the above equations 1 and 2 are as follows: JPEG2023144612000001.jpg9150 JPEG2023144612000002.jpg7150 JPEG2023144612000003.jpg7150 JPEG2023144612000004.jpg7150

[0136] Once the second temperature value T2 is determined, the value T SER is the second minimum temperature limit T min,2 and the second maximum temperature limit T max,2 The temperature can be limited according to a second temperature interval between the values ​​T SER This restriction of is performed by the second restriction operator LIM2.

[0137] If the second reference temperature is the temperature of the gas at the outlet 4 of the oil-injected element 2, then the second minimum temperature limit T min,2 and the second maximum temperature limit T max,2 The value of may vary between, for example, 0°C and 120°C, and this value may be set with an accuracy of, for example, 1°C.

[0138] Optionally, when the second reference temperature is controlled from an old temperature value to a second desired temperature value, the maximum temperature value resulting from the first maximization operator MAX1 is, on the one hand, a maximum temperature decrease value ΔT from the old temperature value. max,down On the other hand, the old temperature value is multiplied by the maximum temperature increase ΔT max,up The maximum temperature value can be limited according to a third temperature interval between the second reference temperature and the value of the second reference temperature plus the third temperature interval. This makes it possible to avoid an excessive decrease or increase in the second reference temperature. This limiting of the maximum temperature value is performed by a third limiting operator LIM3.

[0139] Here, a predetermined time interval Δt can be determined for controlling the old temperature value to the second desired temperature value, and a maximum temperature decrease value ΔT max,downand maximum temperature increase value Δ Tmax,up is positively dependent on the length of this preset time interval Δt.

[0140] Optionally, the second desired temperature value is also less than a third minimum temperature limit value T min,3 and on the other hand the third maximum temperature limit T max,3 and a fourth temperature interval between the temperature of the first and second electrodes.

[0141] If the second reference temperature is the temperature of the gas at the outlet 4 of the oil-injected element 2, then the third minimum temperature limit T min,3 can be set, for example, to a value between 20°C and 80°C, with an accuracy of, for example, 1°C, in order to prevent the formation of condensate at the outlet 4.

[0142] Alternatively, if the oil injection pipe network 6 further comprises a heat recovery system (not shown in FIG. 1) capable of recovering heat from the oil separated by the oil separator 24 to a heat absorbing fluid, the third minimum temperature limit value T min,3 can be set to a high value, for example 105°C. limit value T min,3 Such a high value of allows the heat recovery system to recover a larger amount of heat from the oil in the oil injection pipe network 6, even when the temperature of the heat absorbing fluid is relatively high.

[0143] Third Maximum Temperature limit Value T max,3 can be set, for example, as a value between 100°C and 120°C, with an accuracy of, for example, 1°C.

[0144] The second desired temperature value thus determined by the calculation unit 14 is converted in the control unit 15 into a second reference temperature of A first ratio β1 between the first current value α1 and this second desired temperature value is further used to determine the requested distribution rate.

[0145] The requested distribution percentage can be determined as a continuous percentage between a minimum value of zero and a maximum value of 100% depending on a first ratio β1 according to a first monotonically increasing function.

[0146] On the other hand, the required distribution rate is It can also be determined as a binary proportion, During operation of Device 1, - First current value α 1 but, Higher than the second desired temperature value or the second desired temperature value plus a second safety margin case , or - First current value α 1 but, During the first period, the temperature is higher than the second desired temperature value or the second desired temperature value plus a second safety margin. In the case of Binary Ratio is the maximum value of 100% , - otherwise , the binary ratio is The minimum zero value 。

[0147] Here, the second safety margin can be set to a value between 0°C and 20°C, for example, with an accuracy of 0.1°C.

[0148] The first period may be set to a value between 0 and 255 seconds, for example.

[0149] Based on the required distribution rate determined by the control unit 15, the distribution means 8 are then operated to actually achieve this required distribution rate.

[0150] The required fan 9 speed for controlling the first reference temperature to the first desired temperature value is determined using the second calculation and control unit 22 .

[0151] For this purpose, the requested speed is selected as the highest speed value from a set of speed values, in this case three speed values, which is shown in Figure 2 by the second maximization operator MAX2.

[0152] The first speed value v1 in the set is then the second reference temperature of represents the speed value of fan 9 required to achieve the second desired temperature value.

[0153] When the device 1 is in the first operating range where it has not yet warmed up, i.e., the second reference temperature of Fourth the current If the value α4 is lower than a preset minimum temperature, for example 90° C., required to end the first operating region of this warm-up, the first speed value v1 is equal to a zero value.

[0154] Fourth the current In a second operating range of the device 1, where the value α4 is higher than the preset minimum temperature, the distribution rate is lower than the preset minimum distribution rate or the fourth the current If the value α4 is less than the second desired temperature value, the first speed value v1 is still equal to the zero value.

[0155] The predetermined minimum allocation percentage can be set, for example, as a value between, for example, 0% and, for example, 100%, with an accuracy of, for example, 1%.

[0156] On the other hand, in the second operating region, the distribution ratio of Fifth the current The value α5 is higher than the preset minimum distribution rate and the fourth the current If the value α4 is greater than the second desired temperature value, the first speed value v1 is at least -6th, which represents the operating pressure the current value α6, and - the seventh temperature of the gas at inlet 3 the current Value α7, is determined based on the

[0157] If the motor 5 is a variable speed motor, the first speed value v1 is determined by expressing the rotational speed of the motor 5, for example, according to the following formula: Sudai of 11 the current Value α 11 is also taken into consideration. v1=v 1,raw =E α11 +F·α7+G·α6+H (Equation 7)

[0158] where: the current Value α 11 is the value of the rotational speed of the motor 5 determined as a percentage of the maximum rotational speed of the motor 5.

[0159] In the above equation 7, the first speed value v1 is determined as a percentage of the maximum speed of the fan 9, and the sixth the current The value α6 is determined as the operating pressure in bar and is the seventh the current The value α7 is determined as the temperature of the gas at the inlet 3 in °C.

[0160] If the second reference temperature is the temperature of the gas at the outlet 4 of the oil-injected element 2, the possible value intervals for the constants E, F, G, H in equation 7 are as follows: JPEG2023144612000005.jpg7150 JPEG2023144612000006.jpg7150 JPEG2023144612000007.jpg7150 JPEG2023144612000008.jpg7150

[0161] In the following cases, i.e. -Fourth the current if the value α4 is greater than the second desired temperature value plus the first tolerance value, or - In the second period, the fourth the current if the value α4 is greater than the second desired temperature value plus the first tolerance value, or -Fourth the current if the value α4 is less than the second desired temperature value minus the second tolerance value, or - In the third period, the fourth the current If the value α4 is less than the second desired temperature value minus the second tolerance value, The first velocity value v1 is at least -Distribution ratio of Fifth the current value α5, and -Fourth the current a second ratio β2 between the value α4 and a second desired temperature value; The determination will be further based on the

[0162] The first and second tolerance values ​​may for example be set between values ​​of for example 0°C and for example 20°C with an accuracy of for example 0.1°C.

[0163] The second and third periods can be set, for example, between values ​​of 0 seconds and, for example, 255 seconds.

[0164] The first speed value v1 in this case preferably depends on the second ratio β2 according to a second monotonically increasing function, and alternatively or additionally, preferably depends on the fifth ratio β2 according to a third monotonically increasing function, for example according to the following formula: the current Depends on the value α5. v1=v 1,raw ·α5^P·β2^Z (Eq. 12)

[0165] The possible value intervals for the constants P and Z in Equation 12 are as follows: P=0-4 (Equation 13) Z=0-4 (Equation 14)

[0166] The second velocity value v2 in the set is determined as follows: -Minimum effective temperature of aftercooler 25 of 8th the current The value α8 is the required minimum effective temperature of If the second velocity value v2 is higher than a first velocity value v1, and -8th the current a third ratio β3 between the value α8 and the required minimum effective temperature value; is determined based on Otherwise, the second velocity value v2 is set to zero.

[0167] The required minimum effective temperature is equal to the second condensing temperature of the gas in the aftercooler 25 plus an offset.

[0168] The second speed value v2 preferably depends on the third ratio β3 according to a fourth monotonically increasing function. of 8th the current The value α8 is the required minimum effective temperature of If it is higher than the value, the second velocity value v2 is calculated, for example, according to the following formula: v2=v1 · β3^P (Equation 15)

[0169] In equation 15 above, the second speed value v2 is determined as a percentage of the maximum speed of the fan 9.

[0170] The interval of possible values ​​of the constant P is already given in Equation 13.

[0171] The third velocity value v3 in the set is -First reference temperature of 9th the current Value α9, and -First reference temperature of A preset maximum value, The third speed value is determined based on v 3 is, -9th the current If the value α9 is lower than a preset maximum value, it is zero; -9th the current If the value α9 is higher than a preset maximum value, it represents the maximum speed of the fan 9.

[0172] The preset maximum value can be set between a value of, for example, 90°C and, for example, 120°C, with an accuracy of, for example, 1°C.

[0173] Finally, based on the required speed determined by the second arithmetic and control unit 22, the second motor 12 is activated and the fan 9 actually operates at the required speed.

[0174] The invention is not limited to the embodiments described and illustrated by way of example, and the method, computing control device or device according to the invention can be implemented in any and all variants without departing from the scope of the invention as defined in the claims. [Explanation of symbols]

[0175] 1 device 2 Oil-injected elements 6. Oil injection pipe network 8 Distribution means 9 Fans 10 Oil cooler 11 Bypass 15 Control Unit

Claims

1. A method for controlling a first reference temperature in a device (1) for compressing a gas to a first desired temperature value, said device (1) comprising the following components: an oil-injected element (2) for aspirating said gas at the inlet (3) of said device (1) and compressing said gas to a working pressure at the outlet (4) of the oil-injected element (2); - an oil injection pipe network (6) with outlets (7) for injecting oil into said oil-injected element (2); The oil injection pipe network (6) comprises: - distribution means (8) for distributing said oil between a first portion and a second portion; - an oil cooler (10) cooled by a fan (9) for cooling said first part; a bypass (11) for bypassing said second portion beyond said oil cooler (10); Equipped with First, - the required distribution rate of the first portion is determined in order to bring a second reference temperature of the device (1) to a second desired temperature value, the second reference temperature being the temperature of the gas at the outlet (4) of the oil-injected element (2) or the temperature of the oil at the outlet (7) of the oil-injection pipe network (6); - the distribution rate of the first portion is controlled to the required distribution rate; after that - a required speed of the fan (9) is determined in order to bring the first reference temperature to the first desired temperature value, and if the first reference temperature is the same as the second reference temperature, the required speed is determined based on the second desired temperature value and the distribution ratio; - the speed of said fan (9) is controlled to said required speed, The distribution ratio is controlled by a control unit (15): a first current value α of said second reference temperature 1 , and - said second desired temperature value, The method is controlled based on a non-fuzzy logic algorithm using the input.

2. the second desired temperature value is determined based on a maximum temperature value within a group including a first temperature value T1 and a second temperature value T2; The first temperature value T 1 is a first condensation temperature of the gas at the outlet (4), or the first condensation temperature plus a first safety margin; represents the value of the second reference temperature equal to 2. The method of claim 1, wherein said second temperature value T2 represents the value of said second reference temperature at which the specific energy requirement of said device (1) is minimum.

3. The first temperature value T 1 is the first minimum temperature limit value T min,1 and the first maximum temperature limit value T max,1 3. The method of claim 2, wherein the temperature is limited according to a first temperature interval between

4. The second temperature value T 2 At least a second current value α representative of said operating pressure 2 , and a third current value α representing the temperature of the gas at the inlet (3); 3 , The method of claim 2 , wherein the determination is based on:

5. The second temperature value T 2 is the second minimum temperature limit value T min,2 and the second maximum temperature limit value T max,2 3. The method of claim 2, wherein the temperature is limited according to a second temperature interval between

6. - the second reference temperature is controlled from a current temperature value to the second desired temperature value; and To determine the second desired temperature value, the maximum temperature value is determined on the one hand by a maximum temperature decrease ΔT from the current temperature value. max,down and on the other hand, the current temperature value plus a maximum temperature increase value ΔT max,up plus a third temperature interval between 3. The method of claim 2.

7. The second reference temperature is controlled from the current temperature value to the second desired temperature value in a predetermined time interval Δt, and the maximum temperature decrease value ΔT max,down and the maximum temperature increase value ΔT max,up 7. The method of claim 6, wherein Δt is positively dependent on the length of the preset time interval Δt.

8. The requested distribution ratio is the first current value α 1 and the second desired temperature value, 1 The method of claim 2 , wherein the value is determined according to:

9. The requested allocation percentage varies according to a first monotonically increasing function with respect to the first ratio β between a minimum value of zero and a maximum value of 100%. 1 The method of claim 8 , wherein the method is dependent on

10. The requested distribution ratio is: - the first current value α 1 but, - higher than the second desired temperature value or the second desired temperature value plus a second safety margin, or - if, during a first period of time, the temperature is higher than the second desired temperature value or the second desired temperature value plus the second safety margin; has a maximum value of 100% - otherwise, the minimum zero value, 9. The method of claim 8, comprising:

11. the requested velocity is determined based on a maximum velocity value in a set including a first velocity value v 1 , a second velocity value v 2 , and a third velocity value v 3 ; the device (1) comprises an aftercooler (25) for cooling the gas downstream of the oil-injected element (2), the aftercooler (25) being cooled by the fan (9); said first speed value v 1 represents the value of the speed of said fan (9) required to achieve said second desired temperature value of said second reference temperature; If the eighth current value α 8 of the minimum effective temperature in the aftercooler (25) is higher than the value of the required minimum effective temperature, the second speed value v 2 is said first velocity value v 1 , and a third ratio β 3 between said eighth current value α 8 and the value of said required minimum valid temperature; is determined based on if the eighth current value α 8 is less than or equal to the required minimum valid temperature value, then the second speed value v 2 is set to zero; The third velocity value v 3 is a ninth current value α 9 of said first reference temperature, and a preset maximum value of said first reference temperature, is determined based on The third velocity value v 3 is - equal to zero if said ninth current value α 9 is lower than said preset maximum value; 2. A method according to claim 1, wherein said ninth current value α 9 is equal to a value representative of the maximum speed of said fan (9) if said ninth current value α 9 is higher than said preset maximum value.

12. a fourth current value α of the second reference temperature 4 is higher than a preset minimum temperature, and - the fifth current value α of the distribution ratio 5 is higher than the preset minimum distribution rate, and the fourth current value α 4 is greater than the second desired temperature value; The first velocity value v 1 At least a sixth current value α representing said operating pressure 6 , and a seventh current value α representing the temperature of the gas at the inlet (3); 7 , The method of claim 11 , wherein the determination is based on:

13. the fourth current value α 4 is greater than the second desired temperature value plus a first tolerance; or During a second period, the fourth current value α 4 is greater than the second desired temperature value plus the first tolerance value; or the fourth current value α 4 is less than the second desired temperature value minus a second tolerance value; or During a third period, the fourth current value α 4 is less than the second desired temperature value minus the second tolerance value; The first velocity value v 1 At least the fifth current value α of the distribution ratio 5 , and the fourth current value α 4 and the second desired temperature value, β 2 , The method of claim 12 , further determined based on:

14. The first velocity value v 1 increases the second ratio β according to a second monotonically increasing function. 2 The method of claim 13, wherein the method is dependent on

15. The first velocity value v 1 is increased by the fifth current value α according to a third monotonically increasing function. 5 The method of claim 13, wherein the method is dependent on

16. 12. The method of claim 11, wherein the required minimum effective temperature is equal to a second condensation temperature of the gas in the aftercooler (25) plus an offset.

17. The second velocity value v 2 is a fourth monotonically increasing function of the third ratio β 3 The method of claim 11 , wherein the

18. A computer-controlled assembly for carrying out the method of claim 1, comprising: a first computing and control unit (13) comprising a control unit (15) for controlling a second reference temperature in the device (1) for compressing gas to a second desired temperature value; a second computing and control unit (22) for controlling a first reference temperature of said device (1) to a first desired temperature value; A computer control assembly comprising:

19. 20. An apparatus for compressing gas comprising the computer controlled assembly of claim 18.

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