Steam compressor

Abstract

The present invention comprises: a rotor (1); bearings (2) that supports a rotating shaft (11) of the rotor (1) using a lubricant; a casing (3) that houses the rotor (1) and the bearings (2); a compression chamber (6) that is formed between the rotor (1) and the casing (3), and in which steam introduced into the casing (3) is compressed by the rotor (1); a first shaft sealing device (4b) that is disposed between one of the bearings (2) and the compression chamber (6), and seals the gap between the rotating shaft (11) and the casing (3); an introduction path (36) that is provided in the casing (3) so as to be open to a first space (7) between a bearing (2b) and the first shaft sealing device (4b) in the casing (3); a blower (8) that supplies a gas outside the casing (3) into the first space (7) through the introduction path (36); and a first discharge path (37) that is provided in the casing (3) so as to be open to the first space (7), and discharges the gas in the first space (7) supplied from the blower (8) to the outside of the casing (3).

Description

Steam compressor

[0001] The present invention relates to a steam compressor.

[0002] In a steam compressor, a shaft seal device is provided in the gap between a casing and a rotating shaft between a compression chamber where steam is compressed and a bearing to prevent lubricating oil (lubricant) of the bearing that supports the rotating shaft of a rotor from being contaminated by steam or water droplets, thereby suppressing leakage of steam from the compression chamber side to the bearing side.

[0003] However, it is difficult to completely eliminate steam leakage only with a shaft seal device, and a shaft seal structure that suppresses steam leaked from the shaft seal device from reaching a bearing is disclosed in, for example, Patent Document 1.

[0004] Japanese Patent No. 5670072

[0005] The shaft seal structure disclosed in Patent Document 1 sucks water vapor leaked into the space between the shaft seal device (oil seal) and the bearing together with outside air by a vacuum pump and discharges the water vapor to the outside, thereby suppressing steam from reaching the bearing.

[0006] However, in the shaft seal structure disclosed in Patent Document 1, since the gas in the space between the shaft seal device and the bearing is sucked by the vacuum pump, the space becomes negative pressure, and the absolute amount of steam flowing into the space from the compression chamber can increase. When the absolute amount of steam flowing into the space from the compression chamber increases, the amount of compressed steam produced by the steam compressor decreases. At this time, the work of compressing steam by the steam compressor does not decrease, and as a result, the efficiency of the steam compressor decreases, which is not preferable.

[0007] An object of the present invention is to provide a steam compressor capable of suppressing contamination of lubricating oil of a bearing that supports a rotating shaft by steam or water droplets without reducing the efficiency of the steam compressor.

[0008] The present invention includes several means for solving the above problems, but to give one example, it includes a rotor, a bearing that supports the rotation axis of the rotor using a lubricant, a casing that houses the rotor and the bearing, a compression chamber formed between the rotor and the casing, in which steam introduced into the casing is compressed by the rotor, a first shaft seal device disposed between the bearing and the compression chamber and sealing the gap between the rotation axis and the casing, an introduction passage provided in the casing so as to open into a first space which is the space between the first shaft seal device and the bearing inside the casing, a blower that supplies gas from outside the casing to the first space via the introduction passage, and a first discharge passage provided in the casing so as to open into the first space and discharges the gas in the first space supplied by the blower to the outside of the casing.

[0009] According to the present invention, since gas from outside the casing is introduced into the first space from the introduction passage by a blower, the space between the first shaft seal device and the bearing is pressurized, the absolute amount of steam flowing into the space from the compression chamber can be reduced, and the decrease in the efficiency of the steam compressor can be suppressed. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

[0010] This is a schematic diagram showing a cross-section of a steam compressor according to the first embodiment of the present invention. This is a schematic diagram showing a cross-section of a steam compressor according to the second embodiment of the present invention, a control device for controlling a blower, and a plurality of sensors for inputting physical quantities to the control device. This is a diagram showing an example of a flowchart of processing performed by the processing device of the control device according to the second embodiment of the present invention. This is a blower control map showing the ratio of the blower's airflow to the initial airflow based on the discharge pressure of the steam compressor and the absolute humidity of the outside air according to the second embodiment of the present invention. This is a schematic diagram showing a cross-section of a steam compressor according to the third embodiment of the present invention, a control device for controlling a blower, and a plurality of sensors for inputting physical quantities to the control device.

[0011] The steam compressor of the present invention is a device that compresses low-pressure steam and converts it into high-pressure steam by changing its volume using a rotor (for example, a screw rotor or a Roots rotor).

[0012] The configuration and operation of the steam compressor according to the first to third embodiments of the present invention will be described below with reference to the drawings. In each figure, the same reference numerals indicate the same part.

[0013] (First Embodiment) Figure 1 is a schematic diagram showing a cross-section of a steam compressor according to the first embodiment of the present invention.

[0014] As shown in Figure 1, the steam compressor 100 comprises a rotor 1, a bearing 2 that supports the rotation shaft 11 of the rotor 1, a casing 3 that houses the rotor 1 and the bearing 2, and a first shaft sealing device 4 that seals the gap between the rotation shaft 11 and the casing 3.

[0015] The rotor 1 is a component that rotates to change its volume and compress the steam. In this embodiment, the steam compressor 100 is of the screw type, and the rotor 1 is preferably a pair of screw rotors. If the steam compressor is of the Roots type, the rotor is a Roots rotor. If the steam compressor is of the vane type, the rotor is a vane rotor.

[0016] A pair of screw rotors comprises a male rotor 12 and a female rotor (not shown).

[0017] The male rotor 12 and the female rotor are provided with lobes 13, which are helical portions that mesh with each other and rotate to draw in and compress low-pressure steam LPS and discharge it as high-pressure steam HPS, and a rotating shaft 11 that supports and rotates the lobes 13.

[0018] The rotating shaft 11 has an intake-side rotating shaft 11a that is connected to the end face 13a of the lobe 13 that inhales low-pressure steam LPS, and a discharge-side rotating shaft 11b that is connected to the end face 13b of the lobe 13 that discharges high-pressure steam HPS.

[0019] An electric motor 5 is coupled to the intake-side rotating shaft 11a of the male rotor 12, driving the male rotor 12 to rotate. The male rotor 12, driven by the electric motor 5, then drives the female rotor to rotate. As the male rotor 12 and the female rotor rotate together, low-pressure steam LPS is drawn in, compressed, and discharged as high-pressure steam HPS.

[0020] The bearing 2 is a bearing that rotatably supports the rotating shaft 11 of the rotor 1 using a lubricant (oil or grease, etc.), and has an intake-side bearing 2a that rotatably supports the intake-side rotating shaft 11a, and a discharge-side bearing 2b that rotatably supports the discharge-side rotating shaft 11b. In this embodiment, the bearing 2 uses lubricating oil stored in a bearing chamber 35, which will be described later, as the lubricant.

[0021] The casing 3 is a rigid body that houses the rotor 1 and the bearing 2, and seals the space where steam intake, compression, and discharge take place from the outside. The casing 3 is provided with an intake passage 31, a discharge passage 32, an operating space 33, a shaft hole 34, and a bearing chamber 35.

[0022] The intake passage 31 is a passage for drawing in low-pressure steam (LPS) supplied from boilers, evaporators, etc. The discharge passage 32 is a passage for discharging compressed high-pressure steam (HPS).

[0023] The working space 33 is a space that covers the lobes 13, which are the helical portions of a pair of screw rotors, and has a cylindrical inner surface 33a facing the tips of the lobes 13. Within the working space 33, a compression chamber 6 is formed, surrounded by the cylindrical inner surface 33a and the tooth grooves of the lobes 13, which draws in low-pressure steam LPS from the intake passage 31 and compresses it, and discharges high-pressure steam HPS into the discharge passage 32. In other words, the steam compressor 100 has a compression chamber 6 formed between the rotor 1 and the casing 3, into which the introduced low-pressure steam LPS is compressed by the rotor 1.

[0024] The shaft hole 34 is a hole through which the rotating shaft 11 of the rotor 1 passes into the casing 3, and has an intake-side shaft hole 34a through which the intake-side rotating shaft 11a passes, and a discharge-side shaft hole 34b through which the discharge-side rotating shaft 11b passes.

[0025] The bearing chamber 35 is a room-like space that houses the bearing 2 attached to the rotating shaft 11, and communicates with the shaft hole 34 across the bearing 2. As described above, the bearing chamber 35 stores lubricating oil LO to reduce friction and wear of the bearing 2 and to help the rotating shaft 11 rotate smoothly. The bearing chamber 35 has an intake-side bearing chamber 35a that houses the intake-side bearing 2a and a discharge-side bearing chamber 35b that houses the discharge-side bearing 2b.

[0026] The first shaft sealing device 4 is positioned between the bearing 2 and the compression chamber 6 and seals the gap between the rotating shaft 11 and the casing 3. The first shaft sealing device 4 prevents the low-pressure steam LPS drawn in from the intake passage 31 and the high-pressure steam HPS compressed in the compression chamber 6 from flowing out into the shaft bore 34, reaching the bearing 2, condensing, and contaminating the lubricating oil LO.

[0027] In this embodiment, the first shaft sealing device 4 is preferably a non-contact type shaft sealing device (for example, a labyrinth seal). By making the first shaft sealing device 4 a non-contact type shaft sealing device, the rotating shaft 11 does not come into contact with the first shaft sealing device 4, thereby suppressing energy loss and wear due to friction with the rotating shaft 11.

[0028] The first shaft sealing device 4 includes an intake-side shaft sealing device 4a located in the intake-side shaft hole 34a and a discharge-side shaft sealing device 4b located in the discharge-side shaft hole 34b.

[0029] On the other hand, because the high-pressure steam HPS compressed by the compression chamber 6 is at a high pressure, it is difficult to completely eliminate leakage (zero leak) by the discharge-side shaft seal device 4b. As a result, there is a risk that the high-pressure steam HPS may leak from the discharge-side shaft seal device 4b to the discharge-side bearing 2b, reach the bearing 2b, condense, and contaminate the lubricating oil LO. For this reason, the casing 3 of this embodiment is provided with an inlet passage 36 and a first discharge passage 37.

[0030] The introduction passage 36 is a flow path provided in the casing 3 so as to open into the first space 7, which is the space between the first shaft seal device (discharge side shaft seal device 4b) and the bearing (discharge side bearing 2b) of the casing 3. When gas from outside the casing 3 (hereinafter sometimes referred to as outside air OA) is introduced through the introduction passage 36, the high-pressure steam HPS and the outside air OA mix in the first space 7, and the humidity decreases, thereby suppressing condensation in the first space 7.

[0031] The blower 8 is a device that supplies gas from outside the casing 3 (outside air OA) to the first space 7 via the introduction passage 36. The blower 8 can be a centrifugal, axial flow, or Roots type blower. The blower 8 in this embodiment is a centrifugal blower that blows air by rotating an impeller, and the amount of air blown can be increased or decreased by increasing or decreasing the rotation speed of the impeller.

[0032] A heater 82 may be provided in the connecting passage 81 that connects the blower 8 and the introduction passage 36. By providing the heater 82, the relative humidity of the incoming outside air is lowered by heating the outside air, thereby further reducing the risk of condensation in conditions where condensation is likely to occur, such as when the absolute humidity AHa of the outside air OA is high, the temperature Ta is low, or when the steam compressor 100 is stopped or during the aforementioned startup.

[0033] The first discharge passage 37 is provided in the casing 3 so as to open into the first space 7, and is a passage that discharges the gas in the first space 7 supplied from the blower 8 to the outside of the casing 3.

[0034] As a result, even if the high-pressure steam HPS compressed in the compression chamber 6 leaks from the discharge-side shaft seal device 4b into the first space 7, it is discharged to the outside of the casing 3 through the first discharge passage 37 by the outside air OA introduced into the first space 7 from the inlet passage 36. Therefore, it is possible to suppress the high-pressure steam HPS from reaching the discharge-side bearing 2b, causing condensation and contamination of the lubricating oil LO.

[0035] Furthermore, it is preferable that the first discharge passage 37 connects the bottom 71 of the first space 7 with the lower part of the casing 3. This allows not only steam but also water droplets that have condensed in areas other than the discharge side bearing 2b and accumulated at the bottom 71 of the first space 7 to be discharged from the first space 7.

[0036] [Effects] The steam compressor 100 according to this embodiment includes a rotor 1, a bearing 2 that supports the rotating shaft 11 of the rotor 1 using a lubricant, a casing 3 that houses the rotor 1 and the bearing 2, a compression chamber 6 formed between the rotor 1 and the casing 3, in which steam introduced into the casing 3 is compressed by the rotor 1, a first shaft seal device 4 positioned between the bearing 2 and the compression chamber 6 to seal the gap between the rotating shaft 11 and the casing 3, an introduction passage 36 provided in the casing 3 so as to open into a first space 7 which is the space between the first shaft seal device 4b and the bearing 2b inside the casing 3, a blower 8 that supplies gas from outside the casing 3 (outside air OA) to the first space 7 via the introduction passage 36, and a first discharge passage 37 provided in the casing 3 so as to open into the first space 7 and discharges the gas in the first space 7 supplied by the blower 8 to the outside of the casing 3.

[0037] As a result, high-pressure steam HPS leaking from the first shaft seal device 4b into the first space 7 is discharged to the outside of the casing 3 through the first discharge passage 37 by outside air OA introduced into the first space 7 from the inlet passage 36, thus preventing it from reaching the discharge side bearing 2b. Furthermore, since the first space 7 is pressurized by outside air OA introduced into the first space 7 by the blower 8 from the inlet passage 36, it becomes less likely for high-pressure steam HPS to leak from the first shaft seal device 4b into the first space 7. Therefore, the absolute amount of steam leaking from the compression chamber 6 into the first space 7 is reduced, and the decrease in the efficiency of the steam compressor 100 can be suppressed.

[0038] (Second Embodiment) Figure 2 is a schematic diagram showing a cross-section of a steam compressor according to the second embodiment, a control device for controlling a blower, and a plurality of sensors for inputting physical quantities to the control device.

[0039] The steam compressor 200 of this embodiment differs from the steam compressor 100 of the first embodiment in that it includes a control device 83 that controls the amount of air blown by the blower 8, and a plurality of sensors 9 that detect the physical quantity of the gas and input the physical quantity to the control device 83.

[0040] The control device 83 is electrically connected to the blower 8 and controls the blower 8 to optimize the amount of air introduced into the intake passage 36. In this embodiment, the steam compressor 200 uses a centrifugal blower for the blower 8, so the control device 83 controls the rotation speed of the impeller.

[0041] In this embodiment, the steam compressor 200, controlled by the control device 83, not only prevents high-pressure steam HPS leaking from the discharge-side shaft seal device 4b from reaching the discharge-side bearing 2b and contaminating the lubricating oil through condensation, but also reduces the power consumption of the blower 8.

[0042] The control device 83 is equipped with a processing unit (such as a CPU or other processor) 82a and a storage device (such as RAM or ROM memory) 82b.

[0043] The plurality of sensors (9) are devices that detect physical quantities of high-pressure steam HPS, outside air OA, and a mixture gas MA obtained by mixing outside air OA into high-pressure steam HPS, and output the detected physical quantities as electrical signals to a control device 83 electrically connected thereto. The vapor compressor 200 of the present embodiment includes the following sensors as the plurality of sensors (9).

[0044] First is a pressure sensor 91 that detects the pressure Pd of high-pressure steam HPS discharged from a discharge flow path 32.

[0045] Second is a temperature sensor 92 that detects the temperature Td of high-pressure steam HPS discharged from the discharge flow path 32.

[0046] Third is an upstream temperature and humidity sensor 93 that detects the temperature Ta and humidity Ha of gas outside the casing (outside air OA) introduced into an introduction path 36.

[0047] Fourth is a downstream temperature and humidity sensor 94 that detects the temperature Tm and humidity Hm of gas discharged from a first discharge path 37, which is a mixture gas MA of high-pressure steam HPS leaking from a discharge-side shaft seal device 4b into a first space 7 and outside air OA introduced into the first space 7 from the introduction path 36.

[0048] In the control device 83 of the present embodiment, it is preferable to increase the air blowing volume of the blower 8 (the rotation speed of the impeller) as the pressure Pd of the high-pressure steam HPS detected by the pressure sensor 91 increases.

[0049] This is because an increase in the pressure Pd of high-pressure steam HPS discharged from a compression chamber 6 increases the amount of high-pressure steam HPS leaking from the discharge-side shaft seal device 4b into the first space 7.

[0050] Therefore, it is preferable for the vapor compressor 200 to increase the air blowing volume of the blower 8 as the pressure Pd of the high-pressure steam HPS discharged from the compression chamber 6 increases. This increases the amount of outside air OA introduced into the first space 7 from the introduction path 36, thereby reducing the humidity in the first space 7 and suppressing dew condensation in the first space 7.

[0051] Furthermore, as the amount of outside air OA discharged from the first discharge passage 37 increases, the amount of high-pressure steam HPS discharged from the first discharge passage 37 increases due to the outside air OA, reducing the amount of high-pressure steam HPS in the first space 7 and preventing the high-pressure steam HPS from reaching the discharge-side bearing 2b.

[0052] In this embodiment, it is preferable that the control device 83 increases or decreases the airflow rate of the blower 8 according to the temperature Td of the high-pressure steam HPS detected by the temperature sensor 92.

[0053] This is because, if the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is low, the dew point temperature of the high-pressure steam HPS leaking from the discharge-side shaft seal device 4b into the first space 7 will also decrease. On the other hand, if the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is high, the dew point temperature of the high-pressure steam HPS leaking from the discharge-side shaft seal device 4b into the first space 7 will also increase.

[0054] Therefore, it is preferable for the steam compressor 200 to increase or decrease the airflow rate of the blower 8 in accordance with the temperature Td of the high-pressure steam HPS discharged from the compression chamber 6.

[0055] As a result, when the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is low and the dew point temperature in the first space 7 is reduced, the amount of outside air OA introduced into the first space 7 from the introduction passage 36 is increased, which reduces the humidity in the first space 7 and suppresses condensation in the first space 7.

[0056] Furthermore, if the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is high and the dew point temperature in the first space 7 rises, the amount of outside air OA introduced into the first space 7 from the introduction passage 36 is reduced, thereby suppressing condensation in the first space 7 while also reducing the power consumption of the blower 8.

[0057] Furthermore, in this embodiment, it is preferable that the control device 83 increases the airflow rate of the blower 8 in response to a decrease in the temperature Ta of the outside air OA detected by the upstream temperature and humidity sensor 93.

[0058] In other words, as the temperature Ta of the outside air OA introduced from the introduction passage 36 decreases, the relative humidity in the first space 7 increases, making it easier for the high-pressure steam HPS leaking from the discharge side shaft seal device 4b into the first space 7 to condense.

[0059] Therefore, it is preferable that the amount of air blown by the blower 8 is increased in the steam compressor 200 as the temperature Ta of the gas outside the casing 3 (outside air OA) decreases.

[0060] As a result, the amount of outside air OA introduced into the first space 7 from the introduction path 36 increases, which lowers the humidity in the first space 7 and suppresses condensation of high-pressure steam HPS in the first space 7.

[0061] Furthermore, as the amount of outside air OA discharged from the first discharge passage 37 increases, the amount of high-pressure steam HPS discharged from the first discharge passage 37 increases due to the outside air OA, the amount of high-pressure steam HPS in the first space 7 decreases, and it is possible to suppress the high-pressure steam HPS from reaching the discharge-side bearing 2b.

[0062] The heater 82 may also be electrically connected to the control device 83. This allows for precise control of the output of the heater 82, thereby suppressing condensation within the first space 7 and reducing wasted power consumption.

[0063] Figure 3 is a diagram showing an example of a flowchart of the process executed by the processing unit of the control device according to this embodiment. The processing unit 83a of the control device 83 executes the process shown in Figure 3 using the program stored in the storage device 83b and the input pressure Pd, temperature Td, Ta, Tm, and humidity Ha, Hm.

[0064] Pressure Pd is the discharge pressure of the high-pressure steam (HPS) detected by the pressure sensor 91.

[0065] Temperature Td is the temperature of the high-pressure steam HPS detected by the temperature sensor 92, temperature Ta is the temperature of the outside air OA detected by the upstream temperature and humidity sensor 93, and temperature Tm is the temperature of the mixed gas MA detected by the downstream temperature and humidity sensor 94.

[0066] Humidity Ha is the humidity of the outside air OA detected by the upstream temperature and humidity sensor 93, and humidity Hm is the humidity of the mixed gas MA detected by the downstream temperature and humidity sensor 94.

[0067] First, when the processing unit 83a detects the operator's start operation of the steam compressor 200, it starts the flow shown in Figure 3.

[0068] In step 1, the processing device 83a operates the blower 8 so that the initially set airflow is introduced into the first space 7.

[0069] In step 1, the blower 8 is operated before the rotor 1 in order to prevent condensation from forming when steam comes into contact with the casing 3, whose temperature has decreased due to the stopping of the steam compressor 200. For this reason, the initially set airflow rate is greater than the airflow rate of outside air OA introduced into the first space 7 of the steam compressor 200, where the temperature of the casing 3 has risen due to continuous operation.

[0070] Next, in step 2, the processing device 83a operates the rotor 1. The operation of the rotor 1 causes the steam compressor 200 to draw in and compress the low-pressure steam LPS and discharge it as high-pressure steam HPS.

[0071] Next, in step 3, the processing unit 83a determines whether or not the operator has performed a stop operation on the steam compressor 200.

[0072] If the steam compressor 200 is not stopped (NO), in step 4, the processing device 83a determines whether the temperature Td of the high-pressure steam HPS detected by the temperature sensor 92 is greater than a predetermined temperature Ts. The predetermined temperature Ts is the discharge temperature of the high-pressure steam HPS at which condensation does not occur even when the steam comes into contact with the casing 3.

[0073] If the processing device 83a determines that the temperature Td is not greater than a predetermined temperature Ts (NO), in step 5, it maintains the airflow rate (impeller rotation speed) of the blower 8 and returns to step 3.

[0074] If the processing device 83a determines that the temperature Td is greater than a predetermined temperature Ts (YES), it determines in step 6 whether or not this is the first time the airflow rate has been changed.

[0075] If the processing unit 83a determines that it is the first time the airflow rate has been changed (YES), in step 7, it changes (controls) the airflow rate of the blower 8 based on the pressure Pd of the high-pressure steam HPS discharged from the discharge channel 32 and the humidity Ha of the outside air OA introduced into the inlet channel 36. (That is, it is preferable that the airflow rate of the blower 8 is controlled by the pressure Pd of the high-pressure steam HPS discharged by the rotor 1 and the humidity Ha of the gas (outside air OA) introduced into the inlet channel 36.) The reason for changing (controlling) the airflow rate of the blower 8 using the pressure Pd of the high-pressure steam HPS discharged from the discharge channel 32 is as follows.

[0076] In other words, as the pressure Pd of the high-pressure steam HPS discharged from the compression chamber 6 increases, the amount of high-pressure steam HPS leaking from the discharge-side shaft seal device 4b into the first space 7 increases, the humidity in the first space 7 rises, and condensation is more likely to occur in the first space 7.

[0077] Furthermore, the reason for changing (controlling) the airflow rate of the blower 8 using the humidity Ha of the outside air OA introduced into the introduction path 36 is as follows:

[0078] In other words, when the humidity Ha of the outside air OA introduced into the introduction path 36 increases, the humidity inside the first space 7 increases, making condensation more likely to occur inside the first space 7.

[0079] Therefore, since the airflow rate of the blower 8 is controlled by the pressure Pd of the high-pressure steam HPS discharged by the rotor 1 and the humidity Ha of the gas (outside air OA) introduced into the introduction passage 36, the occurrence of condensation in the first space 7 can be suppressed.

[0080] The following is an example of the processing that the processing device 83a performs in step 7.

[0081] First, the processing unit 83a substitutes the temperature Ta and humidity Ha of the outside air OA detected by the upstream temperature and humidity sensor 93 into the absolute humidity calculation formula to calculate the absolute humidity AHa of the outside air OA introduced from the introduction path 36 (a value that expresses the mass of water vapor in the air as a unit volume of air). Absolute humidity is a value that expresses the mass of water vapor in the air as a unit volume of air.

[0082] Next, the processing unit 83a applies the calculated absolute humidity AHa of the outside air OA and the pressure Pd detected by the pressure sensor 91 to Figure 4 (a blower control map showing the ratio of the blower's airflow rate based on the discharge pressure of the steam compressor and the absolute humidity of the outside air) stored in the storage device 83b. Then, the processing unit 83a changes the airflow rate of the blower 8 from the initially set airflow rate to the airflow rate obtained by multiplying it by the ratio of the blower's airflow rate identified in Figure 4.

[0083] On the other hand, if the processing unit 83a determines that the change in airflow rate is not the first time (NO), it skips step 7 and executes step 8.

[0084] Next, in step 8, the processing unit 83a substitutes the temperature Tm and humidity Hm of the mixed gas MA detected by the downstream temperature and humidity sensor 94 into the absolute humidity calculation formula to calculate the absolute humidity AHm of the mixed gas MA.

[0085] Next, the processing device 83a determines whether the absolute humidity AHm of the mixture MA calculated in steps 9 and 10 is equivalent to the target absolute humidity AHs. The target absolute humidity AHs is, for example, the absolute humidity AHa of the outside air OA. The range for determining whether they are equivalent is, for example, a range of ±1 g / kg (DA) relative to the target absolute humidity AHs.

[0086] Specifically, in step 9, the processing device 83a determines whether the absolute humidity AHm of the calculated mixture MA is greater than the value obtained by adding 1 g / kg (DA) to the target absolute humidity AHs.

[0087] If the processing device 83a determines that the absolute humidity AHm of the mixture MA is not greater than the value obtained by adding 1 g / kg (DA) to the target absolute humidity AHs (NO), then in step 10, it determines whether the absolute humidity AHm of the mixture MA is less than the value obtained by subtracting 1 g / kg (DA) from the target absolute humidity AHs.

[0088] On the other hand, if the processing device 83a determines that the absolute humidity AHm of the mixed gas MA is greater than the value obtained by adding 1 g / kg (DA) to the target absolute humidity AHs, it increases the airflow rate of the blower 8 in step 11 to suppress condensation in the first space 7, and then returns to step 3.

[0089] Furthermore, if the processing device 83a determines that the absolute humidity AHm of the mixed gas MA is less than the value obtained by subtracting 1 g / kg (DA) from the target absolute humidity AHs (YES in step 10), it reduces the airflow rate of the blower 8 in step 12 to suppress the power consumption of the blower 8, and returns to step 3.

[0090] On the other hand, if the processing device 83a determines that the absolute humidity AHm of the mixed gas MA is not less than the value obtained by subtracting 1 g / kg (DA) from the target absolute humidity AHs (NO in step 10), it maintains the airflow rate of the blower 8 in step 5 and returns to step 3.

[0091] On the other hand, if the processing device 83a determines that the steam compressor 200 has been stopped (YES in step 3), it stops the rotor 1 in step 13.

[0092] After stopping the rotor 1 in step 13, the processing unit 83a determines in step 14 whether the elapsed time t1 has exceeded a predetermined time ts.

[0093] If the processing unit 83a determines that the elapsed time t1 has not exceeded the predetermined time ts (NO), it continues operating the blower 8 in step 15 and returns to step 14.

[0094] If the processing device 83a determines that the elapsed time t1 has exceeded a predetermined time ts (YES), it stops the blower 8 in step 16 and ends the process.

[0095] If it is determined that the steam compressor 200 has been stopped (YES in step 3), the reason why the processing device 83a executes steps 13 to 16 is as follows:

[0096] In other words, when the rotor 1 is stopped, high-pressure steam HPS remains in the compression chamber 6 and may leak from the discharge-side shaft seal device 4b into the first space 7, potentially causing condensation. Therefore, the processing device 83a continues to operate the blower 8 until a predetermined time ts has elapsed, during which the high-pressure steam HPS remaining in the compression chamber 6 leaks from the discharge-side shaft seal device 4b into the first space 7, causing the pressure of the high-pressure steam HPS to decrease and preventing further leakage from the discharge-side shaft seal device 4b into the first space 7.

[0097] In addition, instead of determining in step 14 whether the elapsed time t1 has exceeded a predetermined time ts, the processing device 83a may determine whether the absolute humidity AHm of the mixed gas MA is less than or equal to the absolute humidity AHa of the outside air OA (AHm ≤ AHa).

[0098] If the absolute humidity AHm of the mixture MA is less than or equal to the absolute humidity AHa of the outside air OA, then the amount of vapor in the mixture MA has not increased from the amount of vapor in the outside air OA. Therefore, it can be inferred that high-pressure steam HPS is not leaking from the discharge-side shaft seal device 4b into the first space 7.

[0099] Therefore, by continuing to operate the blower 8 until the absolute humidity AHm of the mixed gas MA is less than or equal to the absolute humidity AHa of the outside air OA, condensation in the first space 7 is suppressed.

[0100] [Effects] In this embodiment, it is preferable that the airflow rate of the blower 8 of the steam compressor 200 is controlled by the pressure Pd of the high-pressure steam HPS discharged by the rotor 1 and the humidity Ha of the gas (outside air OA) introduced into the introduction passage 36. That is, it is preferable that the control device 83 increases or decreases the airflow rate of the blower 8 (for example, the rotation speed of the impeller) based on the pressure Pd of the high-pressure steam HPS discharged by the rotor 1 and the humidity Ha of the gas (outside air OA) introduced into the introduction passage 36. This suppresses condensation in the first space 7, reduces contamination of the lubricating oil of the discharge-side bearing 2b, and prevents excessive outside air OA from being introduced into the first space 7 from the introduction passage 36, thereby reducing the power consumption of the blower 8.

[0101] The steam compressor 200 according to this embodiment includes an upstream temperature and humidity sensor 93 that detects the temperature and humidity of the gas (outside air OA) introduced from the introduction passage 36, a downstream temperature and humidity sensor 94 that detects the temperature and humidity of the gas (mixed gas MA) discharged from the first discharge passage 37, and a processing device 83a that calculates the absolute humidity AHa of the gas (outside air OA) introduced from the introduction passage 36 and the absolute humidity AHm of the gas (mixed gas MA) discharged from the first discharge passage 37 from the values ​​detected by the upstream temperature and humidity sensor 93 and the downstream temperature and humidity sensor 94. Preferably, the processing device 83a increases or decreases the airflow rate of the blower 8 (for example, the rotation speed of the impeller) based on the absolute humidity AHa of the outside air OA and the absolute humidity AHm of the mixed gas MA. This suppresses condensation in the first space 7, preventing contamination of the lubricating oil in the discharge bearing 2b. Furthermore, it prevents excessive intake of outside air OA from the introduction passage 36 into the first space 7, thereby reducing the power consumption of the blower 8.

[0102] In this embodiment, it is preferable that the steam compressor 200 continues to operate the blower 8 for a predetermined time ts after the rotor 1 has stopped.

[0103] This is because when rotor 1 is stopped, high-pressure steam (HPS) remains in the compression chamber 6, and there is a risk that it will leak from the discharge-side shaft seal device 4b into the first space 7 and condense.

[0104] In this embodiment, the processing device 83a of the steam compressor 200 continues to operate the blower 8 until a predetermined time ts (the time until the high-pressure steam HPS remaining in the compression chamber 6 stops leaking from the discharge side shaft seal device 4b into the first space 7) has elapsed, thereby suppressing condensation in the first space 7.

[0105] In this embodiment, it is preferable that the steam compressor 200 increases or decreases the airflow rate of the blower 8 according to the temperature Td of the high-pressure steam HPS discharged from the compression chamber 6.

[0106] As a result, when the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is low and the dew point temperature in the first space 7 is reduced, the amount of outside air OA introduced into the first space 7 from the introduction passage 36 is increased, which reduces the humidity in the first space 7 and suppresses condensation in the first space 7.

[0107] Furthermore, if the temperature of the high-pressure steam HPS discharged from the compression chamber 6 is high and the dew point temperature in the first space 7 rises, the amount of outside air OA introduced into the first space 7 from the introduction passage 36 is reduced, thereby suppressing condensation in the first space 7 while also reducing the power consumption of the blower 8.

[0108] (Third Embodiment) Figure 5 is a schematic diagram showing a cross-section of a steam compressor according to the third embodiment, a control device for controlling a blower, and a plurality of sensors for inputting the physical quantity of gas to the control device.

[0109] The differences between the steam compressor 300 of this embodiment and the steam compressor 200 of the second embodiment are as follows.

[0110] Firstly, the first space 7 is divided into a second space 7a, which is the space on the discharge side bearing 2b side, and a third space 7b, which is the space on the discharge side shaft seal device 4b side, and a second shaft seal device 4c is provided to seal the gap between the discharge side rotating shaft 11b and the casing 303.

[0111] Secondly, the casing 3 is provided with a second discharge passage 338 that opens to the third space 7b and discharges the gas in the third space 7b to the outside of the casing 3.

[0112] Thirdly, the first discharge channel 337 has greater flow resistance than the inlet channel 36.

[0113] In detail, the second shaft seal device 4c is located within the first space 7 and is a shaft seal device that seals the gap between the discharge-side rotating shaft 11b and the casing 303.

[0114] The first space 7 is divided by the second shaft sealing device 4c into a second space 7a, which is the space on the discharge side bearing 2b side, and a third space 7b, which is the space on the discharge side shaft sealing device 4b side.

[0115] The second shaft seal device 4c is preferably a non-contact type shaft seal device (e.g., a labyrinth seal), similar to the first shaft seal device 4. By making the second shaft seal device 4c a non-contact type shaft seal device, the discharge-side rotating shaft 11b does not come into contact with the second shaft seal device 4c, thereby suppressing energy loss and wear due to friction with the discharge-side rotating shaft 11b.

[0116] The second discharge passage 338 is a flow path that connects the third space 7b and the outside of the casing 3, and can discharge high-pressure steam (HPS) that has leaked from the discharge-side shaft seal device 4b into the third space 7b.

[0117] The second discharge passage 338, like the first discharge passage 37, preferably connects the bottom 71b of the third space 7b with the lower part of the casing 3. This allows not only steam but also water droplets that have condensed and accumulated at the bottom 71b of the third space 7b to be discharged from the third space 7b.

[0118] Preferably, the first discharge passage 337 has a smaller flow area than the inlet passage 36, so that its flow resistance is greater than that of the inlet passage 36. As a result, the discharge of outside air OA introduced into the inlet passage 36 by the blower 8 from the first discharge passage 337 is suppressed, and the second space 7a is pressurized.

[0119] [Effects] The steam compressor 200 of this embodiment preferably divides the first space 7 into a second space 7a and a third space 7b, and includes a second shaft seal device 4c that seals the gap between the discharge side rotating shaft 11b and the casing 303, and a second discharge passage 338 provided in the casing 3 so as to open the third space 7b, and for discharging the gas in the third space 7b to the outside of the casing 3. As a result, even if high-pressure steam HPS leaks from the discharge side shaft seal device 4b into the third space 7b, the second shaft seal device 4c prevents it from leaking into the second space 7a, and the second discharge passage 338 can discharge it to the outside of the casing 3. Therefore, it is possible to prevent high-pressure steam HPS from reaching the discharge side bearing 2b, condensing, and contaminating the lubricating oil.

[0120] Furthermore, it is preferable that the first discharge passage 337 has a greater flow resistance than the inlet passage 36. As a result, the discharge of outside air OA introduced from the inlet passage 36 from the first discharge passage 337 is suppressed, and the second space 7a is pressurized. Therefore, it is possible to suppress the leakage of high-pressure steam HPS that has leaked into the third space 7b from the second shaft seal device 4c into the second space 7a, thereby suppressing the reduction in the amount of compressed steam by the steam compressor 300 and suppressing the decrease in the efficiency of the steam compressor 300.

[0121] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0122] Furthermore, some or all of the above configurations and functions may be implemented in hardware, for example, by designing them as integrated circuits. Alternatively, the above configurations and functions may be implemented in software by a processor (microcontroller) interpreting and executing programs that implement each function. Information such as programs, tables, and files that implement each function can be stored in memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0123] 1...Rotor, 2...Bearing, 3...Casing, 36...Inlet passage, 37, 337...First discharge passage, 338...Second discharge passage, 4...Shaft seal device, 4c...Second shaft seal device, 6...Compression chamber, 7...First space, 71...Bottom of the first space, 7a...Second space, 7b...Third space, 8...Blower, 83a...Processing device, 9...Sensor, 93...Upstream temperature and humidity sensor, 94...Downstream temperature and humidity sensor, 100, 200, 300...Steam compressor, AHa...Absolute humidity of gas introduced from the inlet passage, AHm...Absolute humidity of gas discharged from the first discharge passage, Ha...Humidity of gas introduced into the inlet passage, HPS...High-pressure steam, OA...Outside air, Pd...Pressure of high-pressure steam, Td...Temperature of high-pressure steam discharged from the compression chamber, ts...Determined time

Claims

1. A steam compressor comprising: a rotor; a bearing that uses a lubricant to support the rotating shaft of the rotor; a casing that houses the rotor and the bearing; a compression chamber formed between the rotor and the casing, through which steam introduced into the casing is compressed by the rotor; a first shaft seal device disposed between the bearing and the compression chamber, sealing the gap between the rotating shaft and the casing; an introduction passage provided in the casing so as to open into a first space which is the space between the first shaft seal device and the bearing within the casing; a blower that supplies gas from outside the casing to the first space via the introduction passage; and a first discharge passage provided in the casing so as to open into the first space, for discharging the gas in the first space supplied by the blower to the outside of the casing.

2. A steam compressor according to claim 1, wherein the amount of air blown by the blower is controlled by the pressure of the high-pressure steam discharged by the rotor and the humidity of the gas introduced into the inlet passage.

3. A steam compressor according to claim 1, characterized in that the first discharge passage connects the bottom of the first space and the lower part of the casing.

4. A steam compressor according to claim 1, comprising: a second shaft seal device that divides the first space into a second space which is the space on the bearing side and a third space which is the space on the first shaft seal device side and seals the gap between the rotating shaft and the casing; and a second discharge passage provided in the casing so as to open into the third space and for discharging the gas in the third space to the outside of the casing.

5. A steam compressor according to claim 4, characterized in that the first discharge passage has greater flow resistance than the inlet passage.

6. A steam compressor according to claim 1, characterized in that the rotor is a pair of screw rotors.

7. A steam compressor according to claim 1, characterized in that the first shaft seal device is a non-contact type shaft seal device.

8. A steam compressor according to any one of claims 1 to 7, characterized in that the amount of air blown by the blower is increased in accordance with the increase in the pressure of the high-pressure steam discharged from the compression chamber.

9. A steam compressor according to any one of claims 1 to 7, characterized in that the amount of air blown by the blower is increased in response to a decrease in the temperature of the gas introduced into the introduction passage.

10. A steam compressor according to any one of claims 1 to 7, comprising: a downstream temperature and humidity sensor for detecting the temperature and humidity of the gas discharged from the first discharge passage; and a processing device for calculating the absolute humidity of the gas discharged from the first discharge passage based on the temperature and humidity detected by the downstream temperature and humidity sensor, wherein the processing device controls the amount of air blown by the blower so that the absolute humidity of the gas discharged from the first discharge passage is within a predetermined range.

11. A steam compressor according to any one of claims 1 to 7, comprising: an upstream temperature and humidity sensor for detecting the temperature and humidity of a gas introduced from the introduction passage; a downstream temperature and humidity sensor for detecting the temperature and humidity of a gas discharged from the first discharge passage; and a processing device for calculating the absolute humidity of the gas introduced from the introduction passage and the absolute humidity of the gas discharged from the first discharge passage based on the temperature and humidity detected by the upstream temperature and humidity sensor and the downstream temperature and humidity sensor, wherein the processing device increases the airflow rate of the blower when the absolute humidity of the gas discharged from the first discharge passage is greater than the absolute humidity of the gas introduced from the introduction passage, and decreases the airflow rate of the blower when the absolute humidity of the gas discharged from the first discharge passage is less than the absolute humidity of the gas introduced from the introduction passage.

12. A steam compressor according to any one of claims 1 to 7, characterized in that the operation of the blower is continued for a predetermined time after the rotor is stopped.

13. A steam compressor according to any one of claims 1 to 7, characterized in that the airflow rate of the blower is increased or decreased according to the temperature of the high-pressure steam discharged from the compression chamber.

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