JP2018189079A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor which cools a motor from the inner side while inhibiting deterioration of a cooling medium and inhibits deterioration of motor output and the efficiency.SOLUTION: A compressor 1 includes: a compressor body 2 which compresses a gas; a motor 3 in which a rotor 33 and a stator 34 are housed in a motor chamber 37 of a motor casing 31 and which rotationally drives the compressor body 2; a gas cooler 6 which cools a compressed gas compressed by the compressor body 2; an introduction passage 15 for introducing the compressed gas cooled by the gas cooler 6 into the motor chamber 37; and a return passage 16 for returning the compressed gas, which is introduced into the motor chamber 37 to cool the interior of the motor 3, to the upstream side of the gas cooler 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a compressor, and more particularly, to a motor cooling structure in a screw compressor.

  In the screw compressor, a pair of male and female screw rotors are rotationally driven by a motor. When the motor is driven to rotate at high speed, the motor generates heat due to electrical loss such as so-called iron loss (hysteresis loss and eddy current loss) and copper loss (loss due to winding resistance).

  In order to cool the generated motor, a cooling jacket is provided on the outer periphery of the motor casing. The motor is cooled by heat exchange with a coolant such as coolant or coolant flowing through the cooling jacket.

  In a screw compressor using a motor that rotates at high speed, as the size of the motor decreases, the cooling jacket provided on the outer periphery of the motor casing also decreases. The cooling jacket cools the motor from the outside and does not cool the motor from the inside. Therefore, the cooling of the motor is insufficient only by cooling with a small cooling jacket, the temperature rises on the surface of the stator coil and the rotor, and the motor output and efficiency are reduced. Therefore, in order to efficiently cool the stator of the motor, a liquid cooling motor having a double cooling structure has been proposed (see Patent Document 1).

JP 2004-343857 A

  The liquid-cooled motor of Patent Document 1 has a double cooling structure of a cooling jacket that cools the outer portion of the motor casing and a coolant passage that cools the inner portion of the motor casing. In the double cooling structure, the motor casing is cooled from the outside and the inside, and the stator of the motor attached to the inside of the motor casing is cooled from the outside. That is, the liquid cooling motor of Patent Document 1 has a structure for cooling the motor from the outside.

  Further, in addition to the above-described double cooling structure, Patent Document 1 discloses a cooling liquid passage or a cooling jacket with respect to a winding end portion that protrudes from both end faces of the stator and is located away from the cooling jacket. It is disclosed that the coolant is sprayed. However, the coolant as the cooling medium also comes into contact with the rotor, resulting in mechanical loss (rotational resistance of the rotor) and lowering the motor output and efficiency. In addition, when lubricating oil is used as the cooling medium, the lubricating characteristics of the lubricating oil that is in direct contact with the heat generating portion are deteriorated, and the life of the lubricating oil is reduced.

  Therefore, the technical problem to be solved by the present invention is to provide a compressor that suppresses deterioration of the cooling medium and cools the motor from the inside to suppress reduction in motor output and efficiency.

  In order to solve the above technical problem, according to the present invention, the following compressor is provided.

  That is, a compressor main body that compresses gas, a rotor and a stator are accommodated in a motor chamber of a motor casing, and a motor that rotates the compressor main body and a compressed gas compressed by the compressor main body are cooled. A gas cooler, an introduction flow path for introducing the gas cooled by the gas cooler into the motor chamber, and a return flow path for returning the compressed gas introduced into the motor chamber and cooling the inside of the motor to the upstream side of the gas cooler And.

  According to the above configuration, the compressed gas cooled by the gas cooler is introduced into the motor chamber through the introduction flow path, and the rotor and stator in the motor are cooled from the inside of the motor by the compressed gas. The compressed gas used for cooling the motor is cooled by the gas cooler through the return channel. Therefore, it is possible to cool the motor from the inside while suppressing deterioration of the compressed gas acting as a cooling medium, and to suppress a decrease in motor output and efficiency.

  In addition to the above features, the present invention can have the following features.

  The compressed gas introduced into the motor chamber is configured to flow through an air gap formed between the rotor and the stator. According to the said structure, a rotor and a stator can be cooled effectively, suppressing generation | occurrence | production of mechanical loss (rotation resistance of a rotor) with the compressed gas which flows through the air gap of a motor.

  The compressed gas introduced into the motor chamber is configured to flow through a multi-groove formed in an inner portion of the motor casing and corresponding to the stator. According to the said structure, a stator and a motor casing can be cooled effectively with the compressed gas which flows through a multi-slot.

  The multi-grooves are formed in a spiral shape. According to the said structure, since compressed gas flows spirally along the surrounding surface of the inner part of a motor casing, a stator and a motor casing can be cooled uniformly.

  The compressed gas cooled by the gas cooler is configured to flow in a cooling jacket portion provided on the outer peripheral portion of the motor. According to this configuration, the motor is cooled from the outside by the compressed gas.

  Oil supplied to the compressor body is configured to flow through a cooling jacket portion provided on the outer peripheral portion of the motor. According to this configuration, the effect of cooling the motor from the outside can be enhanced.

  The temperature of the compressed gas introduced into the motor chamber is configured to be lower than the temperature of the oil flowing through the cooling jacket portion. According to the said structure, a motor can be cooled from an inner side, without raising the temperature of the oil which flows through the cooling jacket part.

  A drain separator that separates and removes moisture contained in the compressed gas is disposed in the introduction flow path. According to the said structure, the damage to a motor can be reduced because the compressed gas which does not contain a moisture flows through the inside of a motor.

  The introduction flow path is provided with an on-off valve that is closed during unload operation. According to the said structure, the power loss of a motor can be reduced because the compressed gas does not flow through the inside of a motor at the time of unload operation with a small load of a motor.

  A flow rate adjusting valve that adjusts the flow rate of the compressed gas according to the coil temperature of the stator is disposed in the introduction flow path. According to this configuration, an appropriate amount of compressed gas flows inside the motor, and the supply loss of compressed gas to the customer can be reduced.

  A check valve for preventing the compressed gas discharged from the compressor main body from flowing into the motor chamber is disposed in the return flow path. According to the said structure, the high temperature compressed gas discharged from a compressor main body can be prevented from flowing back into a motor chamber at the time of unloading driving | operation.

The compressor includes a first compressor body that compresses gas,
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body for compressing the compressed gas cooled by the intercooler;
An aftercooler that is disposed in the discharge flow path and cools the compressed gas compressed by the second compressor body;
A first motor that rotates and drives the first compressor body, with a rotor and a stator housed in a motor chamber of a motor casing;
A second motor for rotating and driving the second compressor body, the rotor and the stator being housed in a motor chamber of a motor casing;
An introduction flow path for introducing the compressed gas cooled by the aftercooler into at least one of the motor chamber of the first motor and the motor chamber of the second motor;
A return flow path that returns the compressed gas that has been introduced into the motor chamber to which the introduction flow path is connected and has cooled the interior of the motor to the upstream side of the intercooler of the intermediate flow path. According to the said structure, compared with the case where a some compressor main body is driven with one motor, each motor is reduced in size and the fall of the motor output and efficiency in each reduced motor can be suppressed.

Moreover, according to another 1st aspect, a compressor is a compressor main body which compresses gas,
A motor in which a rotor and a stator are housed in a motor chamber of a motor casing and rotationally drive the compressor body;
An introduction flow path for introducing the compressed gas compressed by the compressor body into the motor chamber;
An introduction valve provided in the introduction flow path and opening and closing the introduction flow path,
During the unloading operation of the compressor, the introduction valve is opened.

  According to the above configuration, the compressed gas released to the outside during the unload operation can be effectively used for cooling the motor.

  The other first aspect preferably further comprises the following configuration.

  The introduction flow path is provided with an introduction cooler that cools the compressed gas introduced into the motor chamber.

  According to the said structure, since the compressed gas cooled with the introduction cooler is introduce | transduced into a motor chamber, a motor can be cooled efficiently.

According to another second aspect, the compressor includes a plurality of compressor bodies that compress gas,
A motor that is provided for each of the plurality of compressor bodies, a rotor and a stator are housed in a motor chamber of a motor casing, and rotates the compressor body;
At least one introduction flow path for introducing compressed gas compressed by at least one of the compressor bodies into at least one of the motor chambers;
An introduction valve provided in the introduction flow path and opening and closing the introduction flow path,
During the unload operation of the compressor, the introduction valve is opened, and compressed gas is introduced into a predetermined motor chamber among the plurality of motor chambers.

  According to the said structure, when the motor is provided with two or more, it can cool about the predetermined motor which needs cooling.

  The another second aspect preferably further comprises the following configuration.

A first compressor body for compressing gas;
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body that compresses the compressed gas cooled by the intercooler,
The introduction channel introduces the compressed gas cooled by the intercooler into the motor chamber.

  According to the above configuration, since the compressed gas cooled by the intercooler is introduced into the motor chamber, the motor can be efficiently cooled.

  The another first aspect or the another second aspect preferably further includes the following configuration.

A first compressor body for compressing gas;
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body for compressing the compressed gas cooled by the intercooler;
An aftercooler that is disposed in the discharge flow path and cools the compressed gas compressed by the second compressor body;
A return flow path for returning the compressed gas introduced into the motor chamber and cooling the inside of the motor to the upstream side of the intercooler;
An air release valve connected to the motor chamber and communicating or closing the motor chamber and the outside of the machine;
During the unloading operation of the compressor, the release valve is opened, the compressed gas compressed by the second compressor body is introduced into the motor chamber, and the compressed gas introduced into the motor chamber is the motor. Released from the chamber through the air release valve,
During the load operation of the compressor, the discharge valve is closed, the compressed gas cooled by the aftercooler is introduced into the motor chamber, and the compressed gas introduced into the motor chamber is passed through the return flow path. It is returned to the upstream side of the intercooler.

  According to the above configuration, the motor can be cooled by introducing the compressed gas into the motor chamber both during the unload operation and during the load operation. Further, during the load operation, the compressed gas introduced into the motor chamber is returned to the upstream side of the intercooler, so that the compressed gas can be effectively utilized without releasing the compressed gas to the outside.

According to another third aspect, the compressor comprises a compressor body that compresses gas,
A motor in which a rotor and a stator are housed in a motor chamber of a motor casing and rotationally drive the compressor body;
An introduction flow path for introducing the compressed gas compressed by the compressor body into the motor chamber;
A gas discharge part for discharging the gas in the motor chamber to the outside,
The gas in the motor chamber is replaced through the introduction flow path and the gas discharge part.

  According to the said structure, the gas in a motor chamber can be substituted and a motor can be cooled by an introduction flow path and a gas discharge | release part.

  According to the present invention, it is possible to cool the motor from the inside while suppressing deterioration of the cooling medium, and to suppress a decrease in motor output and efficiency.

Schematic which shows the whole structure of the screw compressor which concerns on 1st Embodiment of this invention. The typical longitudinal cross-sectional view of the screw compressor shown in FIG. The typical longitudinal section of the screw compressor concerning a 2nd embodiment of this invention. The typical longitudinal section of the screw compressor concerning a 3rd embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 4th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 5th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 6th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on the 1st modification of this invention. Schematic which shows the whole structure of the screw compressor which concerns on the 2nd modification of this invention. Schematic which shows the whole structure of the screw compressor which concerns on the 3rd modification of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 7th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 8th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 9th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 10th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 11th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 12th Embodiment of this invention. Schematic which shows the whole structure of the screw compressor which concerns on 13th Embodiment of this invention.

  First, the overall configuration of the screw compressor 1 according to the first embodiment of the present invention will be described with reference to FIG.

  1 shows a two-stage screw compressor 1, which includes a low-pressure side first-stage compressor body 2, a motor 3, a high-pressure side second-stage compressor body 4, an intercooler 5, a check valve 7, and an after-sale. A cooler 6, a suction flow path 11, an intermediate flow path 12 and a discharge flow path 13 are provided. For example, the rotor shaft 23 of the first stage compressor body 2 is configured to be rotated by the motor 3 and to rotate in synchronization with the rotor shaft of the second stage compressor body 4.

  A suction flow path 11 is connected to the suction port of the first stage compressor body 2. An intercooler 5 is disposed in the intermediate flow path 12 that connects the discharge port of the first stage compressor body 2 and the suction port of the second stage compressor body 4. A check valve 7 and an aftercooler 6 are disposed in the discharge passage 13 connected to the discharge port of the second stage compressor body 4. The intercooler 5 and the aftercooler 6 each function as a gas cooler that cools the compressed gas. An introduction flow path 15 branched from the discharge flow path 13 is connected to a gas introduction portion 38 (illustrated in FIG. 2) of the motor 3 or the like. A return flow path 16 connected to a gas discharge lower portion 39 (illustrated in FIG. 2) of the motor 3 is connected to the intermediate flow path 12. Since the compressed gas flowing through the return channel 16 is after the motor 3 is cooled, the temperature of the compressed gas is high. The return channel 16 is connected to the upstream side of the intercooler 5 in the intermediate channel 12, so that the compressed gas whose temperature has risen can be cooled by the intercooler 5.

  Next, the structure of the 1st stage compressor main body 2 and the motor 3 among the screw compressors 1 shown in FIG. 1 is demonstrated, referring FIG.

  The first stage compressor body 2 shown in FIG. 2 is a motor direct-coupled oil-free screw compressor. A main body casing 21 of the first stage compressor main body 2 is integrally coupled to a motor casing 31 of the motor 3 through a partition wall casing 24. In the rotor chamber of the main body casing 21, a pair of screw rotors 22 that mesh with each other are rotatably accommodated. The discharge-side shaft portion and the suction-side shaft portion of the rotor shaft 23 are rotatably supported and shaft-sealed by a discharge-side bearing shaft sealing portion 25 and a suction-side bearing shaft sealing portion 27, respectively. A discharge-side bearing shaft seal 25 is disposed in the partition casing 24, and a suction-side bearing shaft seal 27 is disposed on the suction side of the main body casing 21. The suction side of the main casing 21 is closed by a cover 26.

  The rotor shaft 23 of one screw rotor 22 and the output shaft 32 of the motor 3 are directly connected. One screw rotor 22 is rotated by the output shaft 32 via the rotor shaft 23. The rotational driving force transmitted to one screw rotor 22 is transmitted to the other screw rotor 22 via a timing gear. In this way, the pair of screw rotors 22 rotate synchronously in a non-contact state and compress the gas.

  A rotor 33 and a stator 34 are accommodated in a motor chamber 37 of the motor casing 31 of the motor 3. The motor casing 31 has a substantially cylindrical shape, and the non-load side of the motor casing 31 is closed with a cover 42. A gas introduction portion 38 that penetrates the cover 42 is provided at a substantially central portion of the cover 42 so as to face the output shaft 32. A gas discharge upper part 40 that penetrates the motor casing 31 is provided on the upper part of the motor casing 31. A gas discharge lower portion 39 that penetrates the partition casing 24 is provided at the lower portion of the partition casing 24.

  A cooling jacket portion 36 is provided so as to surround the outer peripheral portion of the motor casing 31. Oil is supplied to the cooling jacket portion 36 through an oil passage (not shown). The oil is also supplied to the first-stage compressor body 2 and the second-stage compressor body 4, supplied from the lower side of the cooling jacket portion 36, and discharged from the upper side of the cooling jacket portion 36. The motor casing 31 is effectively cooled by the oil flowing through the cooling jacket portion 36. If only the cooling jacket portion 36 is cooled with oil, the temperature of the oil does not rise so much, so that the deterioration of the oil is small. Further, since the amount of oil used is reduced compared to the case where oil is introduced into the motor chamber 37 and cooled, a small oil cooler and oil pump can be used.

  The temperature of the compressed gas introduced into the motor casing 31 is configured to be lower than the temperature of the oil flowing through the cooling jacket portion 36. According to this configuration, the motor 3 can be cooled from the inside by the compressed gas without increasing the temperature of the oil flowing in the cooling jacket portion 36.

  The stator 34 is attached to the inner surface of the motor casing 31 and includes a core and a coil 35. The coil 35 extends in the axial direction in a cross-sectional view, and is provided with coil end portions that protrude toward the motor casing 31 at both ends in the axial direction of the coil 35. Since the stator 34 generates heat when current flows through the coil 35, the stator 34 functions as a heat generating portion. The heat generated from the stator 34 is conducted to the motor casing 31 and is transferred to the rotor 33 via the air gap 41.

  An output shaft 32 extending from the rotor shaft 23 is inserted into a through-hole at the center of the rotor 33, and the rotor 33 is attached to the rotor 33 by bolts or the like. Therefore, when the rotor 33 rotates, one of the screw rotors 22 rotates via the rotor shaft 23 connected to the output shaft 32.

  An air gap 41 is formed between the stator 34 and the rotor 33. The size of the air gap 41 is, for example, about 1 mm. The compressed gas introduced from the gas introduction part 38 flows through the air gap 41 in the axial direction, whereby the rotor 33 and the stator 34 are cooled. Therefore, the air gap 41 functions as a gas passage through which the compressed gas for cooling flows.

  A spiral multi-slot 43 is formed in the inner portion of the motor casing 31 and corresponding to the stator 34. The spiral multi-slot 43 has a plurality of grooves extending spirally in the axial direction. Since the compressed gas introduced from the gas introduction part 38 flows spirally along the circumferential surface of the inner portion of the motor casing 31 through the spiral multi-grooves 43, the stator 34 and the motor casing 31 can be cooled uniformly. . Accordingly, the helical multi-grooves 43 similarly serve as gas passages.

  Further, in the process in which the compressed gas flows from the gas introduction portion 38 toward the spiral multi-slot groove 43, the counter-load side of the coil end portion of the coil 35 is cooled by the compressed gas. Further, in the process in which the compressed gas flows from the spiral multi-groove 43 toward the gas discharge lower portion 39 and the gas discharge upper portion 40, the load side at the coil end of the coil 35 is cooled by the compressed gas. Conventionally, the coil end portion of the coil 35, which has been difficult to cool, is effectively cooled by the compressed gas related to the spiral multi-groove 43.

  The compressed gas that has flowed through the air gap 41 and the spiral multi-groove 43 is discharged through the gas discharge lower portion 39 and the gas discharge upper portion 40. By providing the gas discharge lower part 39 at the bottom of the motor chamber 37, the drain generated by cooling when the operation is stopped is discharged together with the compressed gas when the operation is restarted, so that it is difficult for the drain to accumulate inside the motor chamber 37.

  A temperature sensor 49 for measuring the coil temperature is attached to the coil 35 of the stator 34. The temperature sensor 49 is used, for example, when controlling the flow rate adjustment valve 54 disposed in the introduction flow path 15 as will be described later.

  According to such a cooling structure using compressed gas, when the operation of the screw compressor 1 is started, the compressed gas cooled by the aftercooler 6 is introduced into the motor chamber 37 through the gas introduction unit 38. In the motor chamber 37, the compressed gas flows in the air gap 41 in the axial direction, and flows in a spiral shape in the spiral multi-groove 43 along the peripheral surface of the inner portion of the motor casing 31. The rotor 33 and the stator 34 in the motor 3 are cooled from the inside of the motor 3 by the compressed gas flowing through the air gap 41 and the spiral multi-grooves 43. The compressed gas used for cooling the motor 3 is returned to the intermediate flow path 12 through the return flow path 16 and cooled by the intercooler 5. Therefore, it is possible to cool the motor 3 from the inside while suppressing deterioration of the compressed gas that functions as a cooling medium, and to suppress a decrease in motor output and efficiency.

  Next, the screw compressor 1 of 2nd Embodiment of this invention is demonstrated, referring FIG. In the second embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the second embodiment, straight multi-grooves 44 are formed in the inner portion of the motor casing 31 and corresponding to the stator 34. The straight multi-row groove 44 has a plurality of groove portions extending linearly in the axial direction. The compressed gas introduced from the gas introduction part 38 flows in the axial direction along the circumferential surface of the inner portion of the motor casing 31 through the linear multi-slot 44, so that the stator 34 and the motor casing 31 can be cooled uniformly. . Accordingly, the straight multi-groove 44 serves as a gas passage.

  According to such a cooling structure using compressed gas, when the operation of the screw compressor 1 is started, the compressed gas cooled by the aftercooler 6 is introduced into the motor chamber 37 through the gas introduction unit 38. In the motor chamber 37, the compressed gas flows in the axial direction through the air gap 41, and flows in the linear multi-slot 44 along the circumferential surface of the inner portion of the motor casing 31 in the axial direction. The rotor 33 and the stator 34 in the motor 3 are cooled from the inside of the motor 3 by the compressed gas flowing through the air gap 41 and the linear multi-grooves 44. The compressed gas used for cooling the motor 3 is returned to the intermediate flow path 12 through the return flow path 16 and cooled by the intercooler 5. Therefore, it is possible to cool the motor 3 from the inside while suppressing deterioration of the compressed gas that functions as a cooling medium, and to suppress a decrease in motor output and efficiency.

  A screw compressor 1 according to a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the third embodiment, the compressed gas cooled by the aftercooler 6 is supplied to the cooling jacket portion 36 disposed on the outer peripheral portion of the motor casing 31. The compressed gas is introduced from the jacket introduction part 46 on the upper side of the cooling jacket part 36 and discharged from the jacket discharge part 47 on the lower side of the cooling jacket part 36. The motor casing 31 is cooled by the compressed gas flowing through the cooling jacket portion 36. In addition, since the drain which generate | occur | produced by cooling by an operation stop is discharged | emitted with compressed gas by restarting an operation | movement, a drain becomes difficult to accumulate in the inside of the cooling jacket part 36. FIG.

  According to such a cooling structure using compressed gas, the compressed gas cooled by the aftercooler 6 is introduced into the motor chamber 37 through the gas introduction unit 38, and the rotor 33 and the stator 34 in the motor 3 are connected. Cooling from the inside of the motor 3. At the same time, the compressed gas cooled by the aftercooler 6 is introduced into the cooling jacket portion 36 through the jacket introduction portion 46, and the motor 3 is cooled from the outside. Therefore, the cooled compressed gas cools the motor 3 from the inside and the outside, and the reduction in motor output and efficiency can be suppressed.

  A screw compressor 1 according to a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, components having the same functions as the components in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the fourth embodiment, as shown in FIG. 5, the drain separator 51 is disposed in the introduction flow path 15. The drain separator 51 separates and removes moisture contained in the compressed gas. According to the said structure, the damage to the motor 3 can be reduced when the compressed gas which does not contain a water | moisture content flows in the inside of the motor 3. FIG.

  A screw compressor 1 according to a fifth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the fifth embodiment, as shown in FIG. 6, the on-off valve 52 is disposed in the introduction flow path 15. The on-off valve 52 is electromagnetically opened and closed by a control unit (not shown), and is closed during the unload operation. According to the said structure, the power loss of the motor 3 can be reduced because the compressed gas does not flow into the intermediate flow path through the inside of the motor 3 during the unload operation where the load of the motor is small. In addition, a check valve 53 is provided in the return flow path 16 in order to prevent the hot gas discharged from the first stage compressor body 2 from flowing back into the motor chamber 37 during the unload operation. Instead of the check valve 53, an open / close valve that is closed before or simultaneously with the open / close valve 52 by a control unit (not shown) may be used.

  A screw compressor 1 according to a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the sixth embodiment, as shown in FIG. 7, the flow rate adjustment valve 54 is disposed in the introduction flow path 15. The flow rate adjusting valve 54 adjusts the flow rate of the compressed gas according to the coil temperature of the stator 34 measured by the temperature sensor 49. When the coil temperature of the stator 34 becomes high, the flow rate adjustment valve 54 is controlled to open, and the flow rate of the compressed gas increases to cool the inside of the motor 3. The flow rate adjusting valve 54 is an orifice or needle valve that can change the flow path area. According to this configuration, an appropriate amount of compressed gas flows through the motor 3 and the supply loss of the compressed gas to the customer can be reduced.

  In addition, this invention is not limited to the specific structure and number of each embodiment mentioned above, The various modifications considered in the range which does not deviate from the content described in the claim can be included. .

  The present invention can also be applied to an oil-cooled screw compressor that supplies oil to a rotor chamber that compresses gas with the screw rotor 22 for the purpose of sealing and cooling. Moreover, although this invention illustrated the two-stage type as the screw compressor 1, it is a single-stage type having only one compressor body, and a multi-stage type having three or more compressor bodies. Is also applicable.

  In each of the above-described embodiments, the rotor shafts of the first-stage compressor body 2 and the second-stage compressor body 4 are connected, and the two compressor bodies 2 and 4 are driven in synchronization by a single motor 3. The screw compressor 1 of the type was illustrated. The present invention is not limited to the above embodiment, and, like the first modification shown in FIG. 8, the rotor shaft of the first stage compressor body 2 and the rotor shaft of the second stage compressor body 4 are connected to two pinion gears. It is also applicable to a two-stage screw compressor 1 that is connected to one motor 3 via one bull gear and drives both compressor bodies 2 and 4 synchronously with one motor 3. Further, as in the second modification shown in FIG. 9, a plurality of compressor bodies are fluidly connected in series, and the motors 3 (that is, the first motor 3a and the second motor 3) provided for each compressor body. This can also be applied to the multistage screw compressor 1 driven by the motor 3b). In the multistage screw compressor in which a motor is provided for each compressor body, each motor is reduced in size as compared with the case where a plurality of compressor bodies are driven by a single motor. Therefore, the present invention can be applied more suitably. .

  In each of the embodiments described above, the drain separator 51, the on-off valve 52, the check valve 53, and the flow rate adjustment valve 54 are provided independently for the screw compressor 1, but the first modification shown in FIG. As in the third modification shown in FIG. 10, two or more of them may be provided in combination.

  As shown in FIG. 9 and FIG. 10, the screw compressor 1 is disposed in a first compressor body 2 that compresses a gas and an intermediate flow path 12, and a first-stage compressor body (first Of the compressor main body) 2, the intercooler 5 that cools the compressed gas compressed by the intercooler 2, the second-stage compressor main body (second compressor main body) 4 that compresses the compressed gas cooled by the intercooler 5, and the discharge An aftercooler 6, which is disposed in the flow path 13 and cools the compressed gas compressed by the second compressor body 4, and the rotor and stator are accommodated in the motor chamber of the motor casing, and the first stage compressor A first motor 3a for rotating the main body (first compressor main body) 2, a rotor and a stator are accommodated in a motor chamber of a motor casing, and a second stage compressor main body (second compressor main body). ) A second motor 3b for rotationally driving 4; The inlet channel 15 for introducing the compressed gas cooled by the aftercooler 6 into at least one of the motor chamber of the first motor 3a and the motor chamber of the second motor 3b, and the one to which the inlet channel 15 is connected A return passage 16 is provided for returning the compressed gas introduced into the motor chamber and cooling the inside of the motor to the upstream side of the intercooler 5 of the intermediate passage 12.

  In each embodiment described above, the return flow path 16 is connected to the intermediate flow path 12 in order to reduce compression loss, but may be connected to the suction flow path 11. When the intercooler 5 is disposed on the intermediate flow path 12, the return flow path 16 is preferably connected to the upstream side of the intercooler 5. In the single-stage screw compressor 1, the return channel 16 is connected to the suction channel 11. In three or more multi-stage screw compressors 1, the return flow path 16 is connected to the intermediate flow path 12 positioned in front of the final stage compressor body, and the intercooler 5 is arranged on the intermediate flow path 12. If it is provided, it is connected to the upstream side of the intercooler 5.

  A screw compressor 1 according to a seventh embodiment of the present invention will be described with reference to FIG. Note that in this seventh embodiment, components having the same functions as those in the first embodiment are given the same reference numerals, and redundant descriptions are omitted.

  In the seventh embodiment, as shown in FIG. 11, an introduction valve 55 is disposed in the introduction flow path 15. The introduction valve 55 is a solenoid valve, and is opened when the compressor is unloaded. The suction flow path 11 is provided with a suction adjustment valve 11a, which is closed during the unload operation of the compressor. The motor chamber of the motor 3 is provided with a gas discharge portion 61 that discharges the gas in the motor chamber to the outside of the motor chamber. The gas discharge part 61 corresponds to either the gas discharge lower part 39 or the gas discharge upper part 40 of the first embodiment, for example. The gas discharge unit 61 may be configured to further release the gas released therefrom to the outside of the machine (atmosphere), or may be configured to return the gas released therefrom to the flow path of the compressor.

  According to the above configuration, since the introduction valve 55 is opened during the unloading operation of the compressor, the compressed gas that has not been used so far can be effectively used for cooling the motor 3. The introduction passage 15 and the gas discharge portion 61 can replace the gas in the motor chamber and cool the motor 3. In the present embodiment, the introduction valve 55 may be omitted, and an air release valve (not shown) that communicates or closes the motor chamber and the outside of the apparatus via the gas discharge unit 61 may be provided. Also by this, the compressed gas is always introduced into the motor chamber via the introduction flow path 15, and the air release valve is opened during the unloading operation of the compressor so that the gas in the motor chamber is discharged from the gas discharge unit 61 to the motor. It can be discharged outside the chamber.

  A screw compressor 1 according to an eighth embodiment of the present invention will be described with reference to FIG. Note that in this eighth embodiment, components having the same functions as those in the seventh embodiment are given the same reference numerals, and duplicate descriptions are omitted.

  In the eighth embodiment, as shown in FIG. 12, an introduction cooler 81 is disposed in the introduction flow path 15.

  According to the above configuration, the introduction flow passage 15 is provided with the introduction cooler 81 that cools the compressed gas introduced into the motor chamber, so that the compressed gas cooled by the introduction cooler 81 is introduced into the motor chamber. Therefore, the motor 3 can be efficiently cooled. In the present embodiment, the introduction cooler 81 is provided on the downstream side of the introduction valve 55, but may be provided on the upstream side of the introduction valve 55.

  A screw compressor 1 according to a ninth embodiment of the present invention will be described with reference to FIG. In the ninth embodiment, components having the same functions as those in the seventh embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the ninth embodiment, as shown in FIG. 13, the motor 3 (3a, 3b) is provided for each of the compressor bodies 2, 4, and the introduction valve 55 (in the introduction flow path 15 to the motor 3a is provided. 55a) is provided, and an introduction valve 55 (55b) is provided in the introduction flow path 15 to the motor 3b. At the time of unloading operation of the compressor, at least one of the introduction valve 55a and the introduction valve 55b is opened, and compressed gas is introduced into a predetermined motor chamber among the plurality of motor chambers. That is, when the compressed gas is introduced into the motor chamber of the motor 3a, the introduction valve 55a is opened, and when the compressed gas is introduced into the motor chamber of the motor 3b, the introduction valve 55b is opened.

  According to the above configuration, at the time of unloading operation of the compressor, at least one of the introduction valve 55a and the introduction valve 55b is opened, and the compressed gas is introduced into the predetermined motor chamber among the plurality of motor chambers. The predetermined motor that needs to be cooled can be cooled. In this embodiment, two motors 3 (motors 3a and 3b) are provided. However, three or more compressor main bodies are provided, motors are provided for the respective compressors, and three motors are provided. More than the body may be provided. In this case, it is desirable to provide as many introduction valves as there are motors. However, the present invention is not limited to this, and one introduction valve may be provided corresponding to two or more motors.

  A screw compressor 1 according to a tenth embodiment of the present invention will be described with reference to FIG. Note that in the tenth embodiment, components having the same functions as those in the seventh embodiment are given the same reference numerals, and redundant description will be omitted.

  In the tenth embodiment, as shown in FIG. 14, an intercooler 5 that cools the compressed gas compressed by the first compressor body 2 is provided in the intermediate flow path 12, and the second compressor body 4 is The compressed gas cooled by the intercooler 5 is further compressed and discharged to the discharge flow path 13. The introduction flow path 15 is connected to the intermediate flow path 12 on the downstream side of the intercooler 5 and the motor chamber. Thereby, the introduction flow path 15 introduces the compressed gas cooled by the intercooler 5 into the motor chamber.

  According to the above configuration, since the compressed gas cooled by the intercooler 5 is introduced into the motor chamber, the motor 3a can be efficiently cooled. In this embodiment, the compressed gas cools only the motor 3a. However, the compressed gas may cool only the motor 3b as shown by the broken line. Further, the compressed gas may cool both the motor 3a and the motor 3b. Here, in FIG. 14, since the gas discharge | release part 61 of the motor 3b is provided as needed, illustration is abbreviate | omitted (FIG. 15 is also the same).

  A screw compressor 1 according to an eleventh embodiment of the present invention will be described with reference to FIG. Note that in the eleventh embodiment, constituent elements having the same functions as those in the seventh embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the eleventh embodiment, as shown in FIG. 15, an introduction channel 17 is provided for introducing the compressed gas cooled by the aftercooler 6 into the motor chamber. An introduction valve 56 is disposed in the introduction channel 17. The introduction valve 56 is a solenoid valve, and is opened during the load operation of the compressor. An air release valve 57 for releasing the gas in the motor chamber to the outside of the motor chamber is connected to the motor chamber of the motor 3a. Further, a return passage 16 is provided for returning the gas in the motor chamber of the motor 3a to the intermediate passage 12 upstream of the intercooler 5, and the return passage 16 has a motor chamber of the motor 3a from the upstream side of the intercooler 5. Is provided with a check valve 58 for prohibiting gas flow.

  During the unloading operation of the compressor, the introduction valve 55 and the discharge valve 57 are opened, and the compressed gas compressed by the compressor body 4 is introduced into the motor chamber of the motor 3a through the introduction flow path 15. . The compressed gas introduced into the motor chamber is released from the motor chamber to the outside (atmosphere) through the air release valve 57. Further, during the load operation of the compressor, the introduction valve 56 is opened, and the introduction valve 55 and the air release valve 57 are closed. The compressed gas cooled by the aftercooler 6 is introduced into the motor chamber of the motor 3 a through the introduction flow path 17, and the compressed gas introduced into the motor chamber is introduced into the intercooler 5 via the return flow path 16. Returned upstream.

  According to the above configuration, the motor 3a can be cooled by introducing the compressed gas into the motor chamber both during the unload operation and during the load operation. Further, during the load operation, by returning the compressed gas introduced into the motor chamber to the upstream side of the intercooler 5, the compressed gas can be effectively used without releasing the compressed gas to the outside (atmosphere). . In this embodiment, the compressed gas cools only the motor 3a. However, the compressed gas may cool only the motor 3b as shown by the broken line. Further, the compressed gas may cool both the motor 3a and the motor 3b. In the present embodiment, the air release valve 57 is connected to a gas discharge path 61 that is different from the gas discharge section 61 connected to the return flow path 16, but the present invention is not limited to this, and the motor 3b side is not limited thereto. As shown by a broken line, an air release valve 57 may be connected to the gas discharge portion 61 connected to the return flow path 16. In this case, the release valve 57 may be connected to the return flow path 16 upstream of the check valve 58.

  In the eleventh embodiment, as in the twelfth embodiment shown in FIG. 16, the rotor shaft of the first stage compressor body 2 and the rotor shaft of the second stage compressor body 4 are connected to two pinion gears and one bull gear. It can be applied to a two-stage screw compressor 1 that is connected to one motor 3 via the motor 1 and drives both compressor bodies 2 and 4 synchronously with one motor 3.

  A screw compressor 1 according to a thirteenth embodiment of the present invention will be described with reference to FIG. Note that, in the thirteenth embodiment, constituent elements having the same functions as those in the eleventh embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the thirteenth embodiment, as shown in FIG. 17, a three-way valve is provided as an introduction valve 59 at the junction of the introduction passages 15, 17, and the return passage 16 is supplied with compressed gas in the motor chamber during loading. A three-way valve is provided as a return valve 60 that returns to the upstream side of the intercooler 5. The introduction valve 59, which is a three-way valve, introduces the compressed gas compressed by the second compressor body 4 into the motor chamber of the motor 3 during unloading operation of the compressor, and after-loading during the loading operation of the compressor. The compressed gas cooled by the cooler 6 is operated to be introduced into the motor chamber of the motor 3. The return valve 60, which is a three-way valve, releases the compressed gas introduced into the motor chamber of the motor 3 to the outside (atmosphere) during the unload operation of the compressor, and the motor 3 during the load operation of the compressor. The compressed gas introduced into the motor chamber is operated so as to return to the upstream side of the intercooler 5. In addition, as indicated by a broken line, a check valve 58 may be provided in the return flow path 16 on the downstream side of the return valve 60.

  According to the above configuration, there is no need to provide a plurality of valves in the introduction passages 15 and 17, and the return passage 16 can also be used as a passage for releasing the compressed gas introduced into the motor chamber to the outside. . As a result, the configuration of the compressor can be simplified.

  In each of the above-described embodiments, the compressed gas flows from the anti-load side of the motor 3 toward the load side. However, the compressed gas flows from the load side of the motor 3 toward the anti-load side. It can also be configured.

1: Screw compressor (compressor)
2: First stage compressor body (first compressor body)
3: Motor
3a: first motor (motor)
3b: second motor (motor)
4: Second stage compressor body (second compressor body)
5: Intercooler (gas cooler)
6: After cooler (gas cooler)
7: Check valve
11: Suction channel
11a: Suction adjustment valve
12: Intermediate flow path
13: Discharge flow path
15: Introduction channel
16: Return channel
17: Introduction channel
21: Body casing
22: Screw rotor
23: Rotor shaft
24: Bulkhead casing
25: discharge-side bearing shaft seal
26: Cover
27: Suction side bearing shaft seal
31: Motor casing
32: Output shaft
33: Rotor
34: Stator
35: Coil
36: Cooling jacket
37: Motor room
38: Gas introduction part
39: Lower gas discharge
40: Gas discharge upper part
41: Air gap
42: Cover
43: Spiral multi-groove
44: Straight multiple groove
46: Jacket introduction part
47: Jacket discharge section
49: Temperature sensor
51: Drain separator
52: Open / close valve
53: Check valve
54: Flow control valve
55: Introduction valve
56: Introduction valve
57: Air release valve
58: Check valve
59: Introduction valve
60: Return valve
61: Gas discharge part

Claims (18)

A compressor body for compressing gas;
A motor in which a rotor and a stator are housed in a motor chamber of a motor casing and rotationally drive the compressor body;
A gas cooler for cooling the compressed gas compressed by the compressor body;
An introduction flow path for introducing the compressed gas cooled by the gas cooler into the motor chamber;
And a return passage for returning the compressed gas introduced into the motor chamber and cooling the inside of the motor to the upstream side of the gas cooler.
The compressor according to claim 1,
A compressor configured such that compressed gas introduced into the motor chamber flows through an air gap formed between the rotor and the stator.
The compressor according to claim 1 or 2,
The compressor is configured such that the compressed gas introduced into the motor chamber flows in a multi-groove formed in an inner portion of the motor casing and corresponding to the stator.
The compressor according to claim 3, wherein
The compressor, wherein the multi-grooves are formed in a spiral shape.
The compressor according to any one of claims 2 to 4,
The compressor configured so that the compressed gas cooled by the gas cooler flows in a cooling jacket portion provided on an outer peripheral portion of the motor.
The compressor according to any one of claims 2 to 4,
A compressor configured such that oil supplied to the compressor main body flows in a cooling jacket portion provided on an outer peripheral portion of the motor.
The compressor according to claim 6, wherein
A compressor configured such that a temperature of compressed gas introduced into the motor chamber is lower than a temperature of oil flowing in the cooling jacket portion.
The compressor according to any one of claims 1 to 7,
A compressor in which a drain separator for separating and removing moisture contained in the compressed gas is disposed in the introduction flow path.
The compressor according to any one of claims 1 to 8,
The compressor is provided with an open / close valve that is closed during unload operation in the introduction flow path.
The compressor according to any one of claims 1 to 9,
The compressor, wherein a flow rate adjusting valve for adjusting a flow rate of the compressed gas according to a coil temperature of the stator is disposed in the introduction flow path.
The compressor according to any one of claims 1 to 10,
The compressor, wherein the return flow path is provided with a check valve that prevents the compressed gas discharged from the compressor body from flowing into the motor chamber.
A first compressor body for compressing gas;
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body for compressing the compressed gas cooled by the intercooler;
An aftercooler that is disposed in the discharge flow path and cools the compressed gas compressed by the second compressor body;
A first motor that rotates and drives the first compressor body, with a rotor and a stator housed in a motor chamber of a motor casing;
A second motor for rotating and driving the second compressor body, the rotor and the stator being housed in a motor chamber of a motor casing;
An introduction flow path for introducing the compressed gas cooled by the aftercooler into at least one of the motor chamber of the first motor and the motor chamber of the second motor;
A compressor including a return flow path that returns the compressed gas that has been introduced into the motor chamber to which the introduction flow path is connected and has cooled the interior of the motor to the upstream side of the intercooler of the intermediate flow path. .
A compressor body for compressing gas;
A motor in which a rotor and a stator are housed in a motor chamber of a motor casing and rotationally drive the compressor body;
An introduction flow path for introducing the compressed gas compressed by the compressor body into the motor chamber;
An introduction valve provided in the introduction flow path and opening and closing the introduction flow path,
The compressor, wherein the introduction valve is opened during unloading operation of the compressor.
The compressor according to claim 13,
The compressor, wherein the introduction flow path is provided with an introduction cooler that cools the compressed gas introduced into the motor chamber.
A plurality of compressor bodies for compressing gas;
A motor that is provided for each of the plurality of compressor bodies, a rotor and a stator are housed in a motor chamber of a motor casing, and rotates the compressor body;
At least one introduction flow path for introducing compressed gas compressed by at least one of the compressor bodies into at least one of the motor chambers;
An introduction valve provided in the introduction flow path and opening and closing the introduction flow path,
The compressor in which the introduction valve is opened and compressed gas is introduced into a predetermined motor chamber among the plurality of motor chambers during unloading operation of the compressor.
The compressor according to claim 15,
A first compressor body for compressing gas;
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body that compresses the compressed gas cooled by the intercooler,
The introduction flow path is a compressor that introduces the compressed gas cooled by the intercooler into the motor chamber.
The compressor according to claim 13 or claim 15,
A first compressor body for compressing gas;
An intercooler disposed in the intermediate flow path for cooling the compressed gas compressed by the first compressor body;
A second compressor body for compressing the compressed gas cooled by the intercooler;
An aftercooler that is disposed in the discharge flow path and cools the compressed gas compressed by the second compressor body;
A return flow path for returning the compressed gas introduced into the motor chamber and cooling the inside of the motor to the upstream side of the intercooler;
An air release valve connected to the motor chamber and communicating or closing the motor chamber and the outside of the machine;
During the unloading operation of the compressor, the release valve is opened, the compressed gas compressed by the second compressor body is introduced into the motor chamber, and the compressed gas introduced into the motor chamber is the motor. Released from the chamber through the air release valve,
During the load operation of the compressor, the discharge valve is closed, the compressed gas cooled by the aftercooler is introduced into the motor chamber, and the compressed gas introduced into the motor chamber is passed through the return flow path. A compressor returned to the upstream side of the intercooler.
A compressor body for compressing gas;
A motor in which a rotor and a stator are housed in a motor chamber of a motor casing and rotationally drive the compressor body;
An introduction flow path for introducing the compressed gas compressed by the compressor body into the motor chamber;
A gas discharge part for discharging the gas in the motor chamber to the outside,
The compressor in which the gas in the motor chamber is replaced through the introduction flow path and the gas discharge unit.

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