Drive motor and compressor arrangement

Abstract

A drive motor and compressor arrangement, the drive motor being for driving a compression member of a compressor element of a compressor arrangement for compressing a gas, the drive motor (1) having a motor housing (2) provided with a motor chamber (3), a motor stator (4) being mounted in the motor chamber (3), a motor shaft (5) being mounted in the motor chamber (3) for driving a compression member (23) of a compressor arrangement (19), the motor stator (4) being provided with a winding (6), the motor housing (2) being provided with a supply passage (7) for a gas supply into the motor chamber (3), the supply passage (7) being provided with a valve (8) configured to allow the gas supply into the motor chamber (3) when a pressure of a gas medium in the motor chamber (3) is below a predetermined threshold level (p th ).

Description

Technical Field

[0001] This utility model relates to a drive motor for driving a compression component of a compressor element in a compressor device for compressing gas, and to a compressor device for compressing gas including such a drive motor.

[0002] More specifically, the present invention relates to a drive motor for driving a compression component of a compressor element of a compressor device for compressing gas, wherein the drive motor has a motor housing having a motor chamber, wherein a motor stator is mounted in the motor chamber, and a motor shaft is mounted in the motor chamber for driving the compression component of the compressor device, and wherein the motor stator is provided with windings. Background Technology

[0003] Such a drive motor is known in the prior art.

[0004] These drive motors may be able to easily reduce the pressure of the gas medium in the motor chamber.

[0005] First, if the motor shaft is mounted in the motor housing via a liquid-lubricated bearing, the liquid leaking from the bearing needs to be extracted from the motor housing and drained. This extraction and drainage will cause a decrease in the pressure of the gas medium inside the motor housing.

[0006] Secondly, if the motor compartment and the compression chamber of the compressor unit are fluidly connected, the pressure drop of the gas medium in the motor compartment may be due to a pressure drop in the compression chamber, for example, when the compressor unit enters an "unloading" mode to temporarily stop the delivery of compressed gas. During this "unloading" mode, the intake valve of the compressor unit is closed, while the drive motor continues to operate at low power. The "unloading" mode allows the compressor unit to stop and restart the delivery of compressed gas very quickly, enabling the compressor unit to meet the required gas demand. When the intake valve is closed, a negative pressure or vacuum will be generated between the intake valve and the compression chamber, as well as at the gas inlet of the compression chamber.

[0007] A decrease in the pressure of the gas medium in the motor compartment can be detrimental to the windings of a motor stator energized at a certain voltage. According to Paschen's Law, due to the decrease in the pressure of the gas medium in the motor compartment, the breakdown voltage when the drive motor is grounded, or the breakdown voltage when the stator windings of the drive motor are short-circuited through the gas medium in the motor compartment, will decrease. Therefore, when the pressure of the gas medium decreases, there is a risk that the breakdown voltage may drop to the voltage at which the windings are energized, and that such electrical breakdown may occur in the gas medium in the motor compartment.

[0008] In vacuum integrated motor applications, it is known to encapsulate the windings in an electrically insulating cast material such as epoxy resin to prevent any electrical breakdown in the gaseous medium within the motor chamber.

[0009] However, this encapsulation of the windings is a time-consuming and expensive process, and once encapsulated, it is not easy to reopen and reopen the encapsulation to rework the windings. The encapsulation is also difficult to extend to large motors.

[0010] By replacing the liquid-lubricated bearing with a grease-lubricated bearing (also known as a "lifetime lubrication (with cap) bearing"), the extraction and drainage of liquid from the liquid-lubricated bearing can be avoided.

[0011] However, once the grease in these grease-lubricated bearings has reached the end of its lifespan, these bearings need to be replaced.

[0012] By using shaft seals to keep the oil within the bearing housing bore of the motor housing and to seal the motor chamber and compression chamber to each other, pressure drop in the gas medium can be avoided.

[0013] However, over time, this shaft seal will wear out and also cause frictional losses during compressor operation. Utility Model Content

[0014] The purpose of this invention is to provide a solution to one or more of the above and / or other disadvantages.

[0015] More specifically, the purpose of this invention is to provide an improved drive motor for driving the compression component of a compressor element in a compressor device for compressing gas, wherein damage to the internal motor components in the motor chamber disposed in the motor housing of the drive motor is avoided due to electrical breakdown in the gas medium contained in the motor chamber.

[0016] Therefore, this utility model relates to a drive motor for driving a compression component of a compressor element in a compressor device for compressing gas.

[0017] The drive motor has a motor housing with a motor chamber.

[0018] The motor stator is installed in the motor housing, and the motor shaft is also installed in the motor housing to drive the compression components of the compressor unit.

[0019] The motor stator is equipped with windings.

[0020] Its characteristic is that the motor housing is provided with a supply channel for allowing gas to enter the motor chamber.

[0021] The supply channel is equipped with a valve configured to allow the gas supply to enter the motor chamber when the pressure of the gas medium in the motor chamber is below a predetermined threshold level.

[0022] The advantage of this drive motor according to the present invention is that when the pressure of the gas medium in the motor chamber drops below a predetermined threshold level, the pressure reduction of the gas medium in the motor chamber can be limited or stopped by the gas supply entering the motor chamber.

[0023] In this way, the pressure of the gas medium in the motor chamber can be prevented from dropping to a pressure level where the breakdown voltage is equal to the voltage at which the motor stator windings are energized, where the drive motor will be grounded or the motor stator windings of the drive motor will be short-circuited by electrical breakdown through the gas medium in the motor chamber.

[0024] In a preferred embodiment of the drive motor according to the present invention, the motor housing is provided with a drive end flange for connecting the motor housing to the compressor components.

[0025] Therefore, the supply channel with the valve is preferably integrated in the drive end flange.

[0026] In this way, the supply channel with the valve can be integrated into the motor housing in the axial direction relative to the axis of rotation of the motor shaft installed in the motor room.

[0027] This allows the drive motor with the supply channel containing the valve to have a compact radial configuration.

[0028] In a next preferred embodiment of the drive motor according to the present invention, the motor housing is provided with a non-drive end flange for connecting the head to the motor housing, wherein the supply channel of the valve is integrated in the non-drive end flange or the head.

[0029] Similarly, in this way, the supply passage with the valve can be integrated into the motor housing in the axial direction relative to the axis of rotation of the motor shaft mounted in the motor compartment. This again allows the drive motor with the supply passage containing the valve to have a compact radial configuration.

[0030] In an optional preferred embodiment of the drive motor according to the present invention, the motor housing is provided with a sheath, wherein the supply channel of the valve is integrated in the sheath.

[0031] In this way, the supply channel with the valve can be integrated into the motor housing in the radial direction relative to the axis of rotation of the motor shaft installed in the motor room.

[0032] This allows the drive motor with the supply channel containing the valve to have a compact axial configuration.

[0033] In a next preferred embodiment of the drive motor according to the present invention, the supply channel is provided with a filter located upstream of the valve.

[0034] The filter prevents foreign objects from entering the motor chamber through the supply channel, which could damage internal motor components such as the motor stator or motor bearings.

[0035] In a next preferred embodiment of the drive motor according to the present invention, the supply channel is provided with a limiter for the gas supply.

[0036] The limiter can be used to regulate the gas supply through the supply channel based on the minimum pressure level required by the gas medium in the motor chamber and the losses inherent in the gas supply. By regulating the gas supply, an optimal balance can be found between the required minimum pressure level and these losses.

[0037] In a next preferred embodiment of the drive motor according to the present invention, the motor shaft is mounted in the motor housing via a liquid-lubricated bearing, wherein the motor housing is provided with a drainage channel system for extracting liquid leaking from the liquid-lubricated bearing from the motor housing via a vacuum source.

[0038] Since the valve allows the gas supply to enter the motor chamber through the supply channel, in this preferred embodiment of the drive motor, the pressure reduction of the gas medium entering the motor chamber caused by the extraction of liquid from the motor housing through the drain channel system can be mitigated.

[0039] Therefore, liquid-lubricated bearings can be used to mount the motor shaft in the motor housing without worrying about the pressure of the gas medium in the motor housing dropping to a pressure level where the breakdown voltage equals the voltage at which the motor stator windings are energized.

[0040] Therefore, the drainage channel system is equipped with limiting devices to restrict the flow of fluid through the drainage channel system.

[0041] In the context of this invention, the term "fluid" refers to a gas, a liquid, or a mixture of gas and liquid. Therefore, a fluid flow can be a gaseous medium flow from the motor chamber, a liquid flow that has leaked from the liquid-lubricated bearing, or a mixture of a gaseous medium from the motor chamber and a liquid leaking from the liquid-lubricated bearing.

[0042] Limiting devices can be used to regulate the pressure of the gas medium in the motor chamber to the required minimum pressure level, in order to prevent electrical breakdown between the drive motor grounding or the windings of the motor stator, and to ensure that liquid is fully discharged from the bearings into the motor housing.

[0043] In a next preferred embodiment of the drive motor according to the present invention, the valve is a check valve.

[0044] In this way, the gas medium will not leak out of the motor chamber through the supply channel with valves, which would otherwise cause the gas medium to be lost into the environment when the pressure of the gas medium in the motor chamber is higher than the atmospheric pressure of the environment driving the motor.

[0045] This utility model also relates to a compressor device for compressing gas, which includes a compressor element having a compressor element housing with a compression chamber.

[0046] The compression chamber includes at least one compression member for compressing the gas within it.

[0047] The compressor device is characterized in that it further includes a drive motor according to any of the embodiments described above for driving the compression member.

[0048] Since the compressor device according to the present invention includes a drive motor according to any of the embodiments described, it is obvious that this compressor device according to the present invention has the same benefits as the embodiments of the drive motor according to the present invention described above.

[0049] In a preferred embodiment of the compressor device according to the present invention, the compressor element housing has an inlet portion for supplying gas into the compression chamber, and the motor housing of the drive motor is directly connected to the inlet portion of the compressor element housing, such that the motor chamber and the compression chamber are in fluid connection.

[0050] Since the valve allows the gas supply to enter the motor chamber through the supply channel, in this preferred embodiment of the compressor unit, the reduction in the pressure level of the gas medium entering the motor chamber due to negative pressure or vacuum generated in the compression chamber at the inlet portion of the compressor element housing can be mitigated.

[0051] Therefore, the motor housing can be directly connected to the inlet portion of the compressor component housing via a fluid connection between the motor chamber and the compression chamber, without worrying about the pressure of the gas medium in the motor chamber dropping to a pressure level equal to the voltage at which the motor stator windings are energized. Attached Figure Description

[0052] To better illustrate the features of this utility model, some preferred embodiments of the drive motor and compressor device according to this utility model are described below by way of example without any limitation, with reference to the accompanying drawings, wherein:

[0053] Figure 1 It is a graph illustrating Paschen's Law;

[0054] Figure 2 A drive motor according to the present invention is shown;

[0055] Figure 3 A compressor device according to the present invention is shown. Detailed Implementation

[0056] Figure 1 It represents the breakdown voltage V that causes a discharge in a gaseous medium between two electrodes spaced a specific distance from each other. B A graph showing the functional relationship between the pressure p in the gaseous medium and the pressure p.

[0057] Breakdown voltage at intermediate pressure p in gas medium int The minimum value V is reached at this point. B,min Therefore, when the pressure level of the gaseous medium is higher than this intermediate pressure p int At that time, the breakdown voltage V B It decreases as the pressure of the gas medium decreases.

[0058] Figure 2 A drive motor 1 according to the present invention is shown, which is used to drive the compression component of the compressor element of a compressor device for compressing gas.

[0059] The drive motor 1 has a motor housing 2, which has a motor chamber 3. The motor stator 4 is installed in the motor chamber 3, and the motor shaft 5 is installed in the motor chamber 3 for driving the compression component of the compression device, wherein the motor stator 4 is provided with windings 6.

[0060] The motor housing 2 is provided with a supply channel 7 for supplying gas into the motor chamber 3. The supply channel 7 is equipped with a valve 8, which is configured to operate when the pressure of the gas medium in the motor chamber 3 falls below a predetermined threshold level p. th At that time, the gas supply is allowed to enter the motor chamber 3.

[0061] In other words, when the pressure of the gas medium in motor chamber 3 drops below a predetermined threshold level p th At that time, valve 8 in supply channel 7 will open to allow the gas supply to enter motor chamber 3.

[0062] Preferably, the predetermined threshold level p th The breakdown pressure level is higher than that when the drive motor 1 is grounded or when the winding 6 of the stator 4 of the drive motor 1 is short-circuited through the gas medium in the motor chamber 3 due to electrical breakdown. More preferably, the predetermined threshold level p th It equals the sum of the breakdown pressure level and the safety margin.

[0063] The supply channel 7 and valve 8 are provided to the motor housing 2 in order to prevent the pressure of the gas medium in the motor chamber 3 from dropping to such a level that the breakdown voltage (at which the drive motor 2 will be grounded, or at which the winding 6 of the motor stator 4 of the drive motor 1 will be short-circuited by the discharge through the gas medium in the motor chamber 3) will drop to the voltage level at which the winding 6 is energized.

[0064] Optionally, the motor housing 2 is provided with a drive end flange 9 for connecting the motor housing 2 to the compressor components.

[0065] Optionally or additionally, the motor housing 2 may be provided with a non-drive end flange 10 for connecting the head 11 to the motor housing 2, wherein the supply channel 7 with the check valve 8 is integrated in the non-drive end flange 10, such as Figure 2 As shown in the example.

[0066] Within the context of this invention, it is not excluded that the supply channel 7 with valve 8 is integrated into another part of the motor housing 2, such as in the drive end flange 9 or in the sheath 12 of the motor housing 2 between the drive end flange 9 and the non-drive end flange 10.

[0067] As an additional option, in this scheme, the supply channel 7 is provided with a filter 13 located upstream of the valve 8.

[0068] As a further alternative, in this scheme, the supply channel 7 is provided with a limiter 14 for the gas supply.

[0069] Furthermore, in this design, the motor shaft 5 is preferably mounted in the motor housing 3 via a liquid-lubricated bearing 15. Consequently, the motor housing 2 is provided with a drainage channel system 16 for extracting liquid leaking from the liquid-lubricated bearing 15 from the motor housing 2 via a vacuum source 17.

[0070] More preferably, the drain channel system 16 is provided with a limiting device 18 to restrict the fluid flow through the drain channel system 16. Even more preferably, the limiting device 18 can be controlled to regulate the pressure of the gas medium in the motor chamber 3 to a specific pressure level, at which electrical breakdown between the windings 6 or grounding of the drive motor 1 is avoided on the one hand, and adequate lubrication of the liquid-lubricated bearing 15 is ensured on the other hand.

[0071] As a further alternative, in this scheme, valve 8 is a check valve, which prevents the gas medium in motor chamber 3 from leaking out of motor chamber 3 and being lost into the environment when the pressure of the gas medium in motor chamber 3 is higher than the atmospheric pressure of the environment driving motor 1.

[0072] However, within the context of this invention, it is not excluded that the valve in the supply channel may be implemented as a regulating valve, the opening of which may be adjusted based on the measured pressure of the gas medium in the motor chamber.

[0073] Figure 3 A compressor device 19 for compressing gas according to the present invention is shown, in this embodiment being a screw compressor device.

[0074] The compressor unit 19 includes a compressor element 20, which in this embodiment is a screw compressor element, having a compressor element housing 21, which is provided with a compression chamber 22.

[0075] The compression chamber 22 includes at least one compression member 23, in this embodiment a screw rotor, for compressing the gas in the compression chamber 22.

[0076] The compressor unit 19 also includes, for example Figure 2 The drive motor 1 shown is used to drive the compression member 23.

[0077] The compressor housing 21 has an inlet portion for supplying gas into the compression chamber 22.

[0078] In this scheme, the motor housing 2 of the drive motor 1 is directly connected to the inlet portion of the compressor component housing 21, so that the motor chamber 3 and the compression chamber 22 are fluidly connected to each other.

[0079] Because the motor chamber 3 and the compression chamber 22 are in fluid communication, a pressure drop in the compression chamber 22 will cause a pressure drop in the gas medium in the motor chamber 3, for example, when the compressor unit enters the "unloading" mode. Nevertheless, the supply passage 7 with valve 8 ensures that the pressure of the gas medium in the motor chamber 3 will never drop to a breakdown pressure level that would cause electrical breakdown through the gas medium in the motor chamber 3.

[0080] This invention is by no means limited to the embodiments described by way of example and shown in the accompanying drawings, but rather can be implemented in various forms or sizes as to the drive motor of a compressor device for compressing gas according to this invention, or a compressor device including such a drive motor, without departing from the scope of this invention as defined in the claims.

Claims

1. A drive motor for driving a compression component of a compressor element in a compressor device for compressing gas. The drive motor (1) has a motor housing (2), and the motor housing is provided with a motor chamber (3). The motor stator (4) is installed in the motor chamber (3), and the motor shaft (5) is installed in the motor chamber (3) for driving the compression member (23) of the compressor unit (19). The motor stator (4) is provided with windings (6). Its features The motor housing (2) is provided with a supply channel (7) for supplying gas into the motor chamber (3). The supply channel (7) is provided with a valve (8) configured to allow gas supply to enter the motor chamber (3) when the pressure of the gas medium in the motor chamber (3) is below a predetermined threshold level.

2. The drive motor according to claim 1, characterized in that, The motor housing (2) is provided with a drive end flange (9) for connecting the motor housing (2) and the compressor component (20).

3. The drive motor according to claim 2, characterized in that, The supply channel (7) having the valve (8) is integrated in the drive end flange (9).

4. The drive motor according to claim 1 or 2, characterized in that, The motor housing (2) is provided with a non-drive end flange (10) for connecting the head (11) to the motor housing (2), wherein the supply channel (7) having the valve (8) is integrated in the non-drive end flange (10) or the head (11).

5. The drive motor according to claim 1 or 2, characterized in that, The motor housing (2) is provided with a sheath (12), wherein the supply channel (7) having the valve (8) is integrated in the sheath (12).

6. The drive motor according to any one of claims 1 to 3, characterized in that, The supply channel (7) is provided with a filter (13) upstream of the valve (8).

7. The drive motor according to any one of claims 1 to 3, characterized in that, The supply channel (7) is provided with a limiter (14) for the gas supply.

8. The drive motor according to any one of claims 1 to 3, characterized in that, The motor shaft (5) is mounted in the motor chamber (3) via a liquid lubricating bearing (15), wherein the motor housing (2) is provided with a drain channel system (16) for extracting liquid leaking from the liquid lubricating bearing (15) from the motor housing (2) via a vacuum source (17).

9. The drive motor according to claim 8, characterized in that, The drainage channel system (16) is provided with a limiting device (18) for limiting the flow of fluid through the drainage channel system (16).

10. The drive motor according to any one of claims 1 to 3, characterized in that, The valve (8) is a check valve.

11. A compressor device for compressing gas, comprising a compressor element (20) having a compressor element housing (21) wherein a compression chamber (22) is provided in the compressor element housing. The compression chamber (22) includes at least one compression member (23) for compressing the gas in the compression chamber (22). Its features are, The compressor unit (19) further includes a drive motor (1) according to any one of the preceding claims for driving the compression member (23).

12. The compressor device according to claim 11, characterized in that, The compressor component housing (21) has an inlet portion for supplying gas into the compression chamber (22), and the motor housing (2) of the drive motor (1) is directly connected to the inlet portion of the compressor component housing (21), such that the motor chamber (3) and the compression chamber (22) are in fluid connection.

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