JP5535749B2 - Dry gas seal structure - Google Patents

Description

  The present invention relates to a dry gas seal structure provided through a housing.

  In a rotating machine provided with a rotating shaft through a housing, a dry gas seal structure is widely used as a sealing structure for sealing between the rotating shaft and the housing (for example, see Patent Document 1). Here, FIG. 13 is a schematic longitudinal sectional view showing a dry gas seal structure 70 according to a conventional example. As shown in the figure, the dry gas seal structure 70 is composed of a rotating ring 72 fixed to a rotating shaft 71 and integrally rotating, and a stationary ring 74 provided in a housing 73 so as to face the rotating ring 72. Then, a spiral groove (not shown) is formed on the surface of the rotating ring 72, and the stationary ring 74 is urged toward the rotating ring 72 by the coil spring 75. According to such a configuration, when the rotating shaft 71 is stopped, the rotating ring 72 and the stationary ring 74 are in contact with each other by the biasing force of the coil spring 75. On the other hand, when the rotating shaft 71 rotates, the gas in the housing 73 is introduced into the spiral groove, and a minute seal gap 76 is generated between the rotating ring 72 and the stationary ring 74 by the dynamic pressure effect. A small amount of gas in the housing 73 leaks to the outside through the seal gap 76, so that the space between the rotating shaft 71 and the housing 73 is sealed.

JP 2004-190783 A

However, when the conventional dry gas seal structure 70 is applied to a pump having a high discharge pressure such as a so-called CO ₂ injection pump, there is a problem that a problem occurs in the seal gap 76 generated between the rotating ring 72 and the stationary ring 74. There is. Here, FIG. 14 is an explanatory diagram for explaining the problems of the conventional dry gas seal structure 70. When applying the dry gas seal structure 70 in CO ₂ injection pump, CO ₂ accommodated in the housing 73, such as temperature pressure a 20MPa is supercritical state such as 30 ° C. or higher. Under such a supercritical state, when the temperature of CO ₂ in the housing 73 is still low before the rotation shaft 71 starts to be driven, for example, when the temperature of CO ₂ is 50 ° C. as shown in FIG. When this CO ₂ passes through the seal gap 76 and is depressurized, its state changes from the supercritical state, and a gas-liquid two-phase state, that is, a state where gas and liquid are mixed is obtained. Then, physical properties of CO _2, specifically density and viscosity changes rapidly. When rotation driving is started in this state, the behavior of the stationary ring 74 urged by the coil spring 75 becomes unstable, and damage such as the stationary ring 74 and the rotating ring 72 coming into contact with each other and burning occurs. The “supercritical state” in the present invention means a point having a limit temperature or pressure at which a gas and a liquid can coexist, that is, a state exceeding the critical point.

Further, when the temperature of CO ₂ in a pre-start driving the housing 73 of the rotary shaft 71 is still low, for example when the temperature of CO ₂ as shown in FIG. 7 is 40 ° C., CO ₂ in the supercritical state is Viscosity is high compared to CO ₂ in a gaseous state. When rotational driving is started in this state, the amount of viscous heat generated when CO ₂ passes through the seal gap 76 becomes large, and excessive thermal deformation is caused such that the rotating ring 72 and the stationary ring 74 come into contact with each other. Occurs.

Further, when the temperature of the CO ₂ in the housing 73 is still low before the rotation shaft 71 starts to be driven, the CO ₂ adiabatically expands when passing through the seal gap 76, so that the CO at the exit portion of the seal gap 76. The temperature of ₂ may be below freezing. In this case, the moisture in the atmosphere becomes ice around the outlet portion of the seal gap 76, and there arises a problem that the seal gap 76 is blocked or the sealing surfaces of the rotary ring 72 and the stationary ring 74 are damaged.

  The present invention has been made in consideration of such circumstances, and its purpose is to start driving the rotating shaft even when applied to a rotating machine in which a fluid in a supercritical state is accommodated inside the housing. It is an object of the present invention to provide a dry gas seal structure that does not sometimes cause problems in the seal gap.

In order to achieve the above object, the present invention employs the following means. That is, a dry gas seal structure according to the present invention includes a housing that contains a fluid in a supercritical state, a rotary shaft that is provided through the housing and is driven to rotate, and is provided so as to surround the rotary shaft. A rotating ring that rotates integrally with the rotating ring, provided in the housing, contacting the rotating ring all around when the rotating shaft is stopped, and having a seal gap between the rotating ring and the rotating shaft when rotating. A stationary ring that is stationary at a point, a piping that supplies a portion of the fluid contained in the housing to the inlet portion of the seal gap, a temperature control device that adjusts the temperature of the fluid flowing through the piping, A controller for controlling the operation of the temperature control device so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotating shaft, and the inlet portion of the seal gap is provided in the pipe line Fluid supplied to A circulation pump that circulates and supplies the fluid to the inlet portion of the seal gap is provided, and the temperature control device includes a heater that heats the fluid flowing through the piping, and the heat source of the heater is the circulation pump or the It is one of lubricating oil pumps that supplies lubricating oil to a bearing that rotatably supports a rotating shaft .

According to such a configuration, the supercritical fluid heated by the temperature control device is supplied before the rotation shaft starts to be driven, so that the inlet portion of the seal gap is heated to a predetermined temperature in advance.
In addition, since a part of the fluid accommodated in the housing is circulated and repeatedly supplied to the inlet portion of the seal gap, it is not necessary to heat all of the fluid accommodated in the housing. Therefore, it is possible to shorten the time required for controlling the temperature of the fluid by the temperature control device, and it is possible to reduce the capacity of the heater constituting the temperature control device.
In addition, since it is not necessary to provide a dedicated heater for heating the fluid, cost reduction can be achieved.

Further, the dry gas seal structure according to the present invention includes a housing that contains a fluid in a supercritical state, a rotating shaft that is provided to pass through the housing and is driven to rotate, and is provided so as to surround the rotating shaft. A rotating ring that rotates integrally with the rotating ring, provided in the housing, contacting the rotating ring all around when the rotating shaft is stopped, and having a seal gap between the rotating ring and the rotating shaft when rotating. A stationary ring that is stationary, a heater provided in at least one of the rotating ring and the stationary ring, and an inlet portion of the seal gap is heated to a predetermined temperature before driving the rotating shaft, and a control unit for controlling the operation of the heater, inside formed flow passage through which fluid flows in the supercritical state of the housing, immediately before the portion of the sealing gap is formed narrower than other portions And wherein the door.

According to such a configuration, the entrance portion of the seal gap is heated in advance to a predetermined temperature by the heater provided in the rotating ring or the stationary ring before the driving of the rotating shaft is started. Further, since it is not necessary to install a temperature control device for adjusting the temperature of the fluid outside the housing, it is possible to save space as the entire rotating machine.
According to such a configuration, after the driving of the rotating shaft is started, the inlet portion of the seal gap is heated by the stirring loss when the fluid flows through the narrow portion of the flow passage. Therefore, the temperature control device and the heater used for heating the inlet portion of the seal gap before the start of driving can be stopped after the driving of the rotary shaft is started. Therefore, the cost can be reduced because the running cost of the temperature control device and the heater becomes unnecessary.

Further, the dry gas seal structure according to the present invention includes a housing that contains a fluid in a supercritical state, a rotating shaft that is provided to pass through the housing and is driven to rotate, and is provided so as to surround the rotating shaft. A rotating ring that rotates integrally with the rotating ring, provided in the housing, contacting the rotating ring all around when the rotating shaft is stopped, and having a seal gap between the rotating ring and the rotating shaft when rotating. The heater is provided at a position immediately before the seal gap in the housing, and before the rotary shaft is driven, the inlet portion of the seal gap is heated to a predetermined temperature. and a control unit for controlling the operation, inside formed flow passage through which fluid flows in the supercritical state of the housing, this immediately before portions of the sealing gap is formed narrower than other portions The features.

According to such a configuration, the inlet portion of the seal gap is heated in advance to a predetermined temperature by the heater provided in the housing before the driving of the rotating shaft is started. Further, since it is not necessary to install a temperature control device for adjusting the temperature of the fluid outside the housing, it is possible to save space as the entire rotating machine.
According to such a configuration, after the driving of the rotating shaft is started, the inlet portion of the seal gap is heated by the stirring loss when the fluid flows through the narrow portion of the flow passage. Therefore, the temperature control device and the heater used for heating the inlet portion of the seal gap before the start of driving can be stopped after the driving of the rotary shaft is started. Therefore, the cost can be reduced because the running cost of the temperature control device and the heater becomes unnecessary.

Further, the dry gas seal structure according to the present invention includes a housing that contains a fluid in a supercritical state, a rotating shaft that is provided to pass through the housing and is driven to rotate, and is provided so as to surround the rotating shaft. A rotating ring that rotates integrally with the rotating ring, provided in the housing, contacting the rotating ring all around when the rotating shaft is stopped, and having a seal gap between the rotating ring and the rotating shaft when rotating. A stationary ring that is stationary at a point, a piping that supplies a portion of the fluid contained in the housing to the inlet portion of the seal gap, a temperature control device that adjusts the temperature of the fluid flowing through the piping, A controller that controls the operation of the temperature control device so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotating shaft, and is formed inside the housing and is in the supercritical state. Fluid flows Flow passage, characterized in that the immediately preceding portion of the sealing gap is formed narrower than the other portions.
In addition, a circulation pump may be provided in the pipeline so that the fluid supplied to the inlet portion of the seal gap is circulated and supplied again to the inlet portion of the seal gap.
In addition, the temperature control device includes a heater that heats the fluid flowing through the piping, and the heat source of the heater supplies lubricating oil to the circulating pump or a bearing that rotatably supports the rotating shaft. Any of lubricating oil pumps may be used.

  According to such a configuration, after the driving of the rotary shaft is started, the inlet portion of the seal gap is heated by the stirring loss when the fluid flows through the narrow portion of the flow passage. Therefore, the temperature control device and the heater used for heating the inlet portion of the seal gap before the start of driving can be stopped after the driving of the rotary shaft is started. Therefore, the cost can be reduced because the running cost of the temperature control device and the heater becomes unnecessary.

  According to the dry gas seal structure of the present invention, the inlet portion of the seal gap is heated in advance before starting the driving of the rotary shaft, so the temperature of the fluid in the supercritical state that passes through the seal gap at the start of driving of the rotary shaft. Becomes higher. Therefore, when the fluid in the supercritical state is depressurized when passing through the seal gap, the fluid changes from the supercritical state to the gas state. As a result, the physical properties of the fluid do not change abruptly and the behavior of the stationary ring is stable, so that it is possible to prevent the stationary ring and the rotating ring from coming into contact with each other and causing seizure.

  In addition, the temperature of the fluid passing through the seal gap at the start of driving of the rotating shaft increases, so the viscosity of the fluid decreases. As a result, the amount of viscous heat generated when the fluid passes through the seal gap is reduced, and thermal deformation does not occur in the stationary ring or the like.

  Furthermore, since the temperature of the fluid that passes through the seal gap increases when driving of the rotary shaft starts, even if the fluid adiabatically expands when passing through the seal gap, the temperature of the fluid falls below the freezing point at the exit portion of the seal gap. Can be prevented. Accordingly, there is no problem that moisture in the atmosphere becomes ice around the outlet portion of the seal gap, thereby closing or damaging the seal gap.

1 is a schematic longitudinal sectional view showing a dry gas seal structure according to a first embodiment of the present invention. Schematic diagram showing the structure of a CO ₂ circulation system. The schematic diagram which shows the structure of a leak discharge system. Flowchart showing a flow of processing when starting the CO ₂ injection pump having a dry gas seal structure according to a first embodiment of the present invention. Flowchart showing a flow of processing when starting the CO ₂ injection pump having a dry gas seal structure according to a first embodiment of the present invention. An explanatory diagram for explaining the operation and effect of heating the seal gap before start of driving the rotating shaft, the graph on the vertical axis the pressure of CO ₂ the enthalpy of CO ₂ in the horizontal axis. An explanatory diagram for explaining the operation and effect of heating the seal gap before start of driving the rotating shaft, the graph on the vertical axis the viscosity of the CO ₂ pressure of CO ₂ in the horizontal axis. The schematic longitudinal cross-sectional view which shows the dry gas seal structure which concerns on 2nd Embodiment of this invention. The partial expansion longitudinal cross-sectional view which shows the modification of 2nd Embodiment. The schematic longitudinal cross-sectional view which shows the dry gas seal structure which concerns on 3rd Embodiment of this invention. The schematic longitudinal cross-sectional view which shows the dry gas seal structure which concerns on 4th Embodiment of this invention. The partial expansion longitudinal cross-sectional view which shows the modification of 4th Embodiment. The schematic longitudinal cross-sectional view which shows the dry gas seal structure concerning a prior art example. An explanatory diagram for explaining a problem of a conventional dry gas seal structure, the graph on the vertical axis the pressure of CO ₂ the enthalpy of CO ₂ in the horizontal axis.

  Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the dry gas seal structure according to the first embodiment of the present invention will be described. FIG. 1 is a schematic longitudinal sectional view showing a dry gas seal structure 10 of the present embodiment. The dry gas seal structure 10 includes a housing 12 in which a plurality of flow paths 11 are formed, a rotary shaft 13 that is provided through the housing 12 and is driven to rotate, and a bearing 14 that rotatably supports the rotary shaft 13; A lubricating oil pump 15 for supplying lubricating oil to the bearing 14, a first seal structure 16 and a second seal structure 17 provided along the rotary shaft 13, and a first seal structure 16 of the housing 12 provided on the inner side of the machine. Two in-machine labyrinths 18, two out-of-machine labyrinths 19 provided outside the second seal structure 17 of the housing 12, and the inside of the first seal structure 16 via the circulation pipe 20. And a leak discharge system 23 connected to the outside of the machine from the first seal structure 16 via a discharge pipe line 22.

The housing 12 constitutes a wall surface of the CO ₂ injection pump. The housing 12 contains CO ₂ (carbon dioxide) in a supercritical state. In the housing 12, the first flow path 11 </ b> A is located in the middle of the two in-machine labyrinths 18, the second flow path 11 </ b> B is located in the machine-inside position from the first seal structure 16, and the first seal structure 16 is functional. Third flow paths 11C are formed at the outer positions, respectively.

  As shown in FIG. 1, the first seal structure 16 includes a rotary ring 25 fixed to a shaft sleeve 24 that rotates integrally with the rotary shaft 13, and a coil spring 27 having one end attached to a retainer 26 fixed to the housing 12. A stationary ring 28 fitted into a recessed groove formed in the retainer 26 and attached to the other end of the coil spring 27; a mounting position of the rotary ring 25 on the shaft sleeve 24; and a stationary ring 28 attached to the retainer 26. And O-rings 29 provided at various places for sealing the position. Although not shown in detail in FIG. 1, a spiral groove is formed on the seal surface 25 a of the rotating ring 25, that is, the surface facing the stationary ring 28. A spiral groove may be formed on the seal surface 28 a of the stationary ring 28, that is, the surface on the side facing the rotating ring 25.

According to the first seal structure 16 configured as described above, when the rotation of the rotating shaft 13 is stopped, the sealing surface 28a of the stationary ring 28 is changed to the sealing surface 25a of the rotating ring 25 by the biasing force of the coil spring 27. Close contact with. Thereby, the first seal structure 16 seals the space between the rotary shaft 13 and the housing 12 so that CO ₂ in the machine does not leak out of the machine. On the other hand, when the rotating shaft 13 starts to rotate, CO _{2 in} the machine is introduced into a spiral groove (not shown) formed on the seal surface 25a of the rotating ring 25, and the rotating ring 25 is caused by the dynamic pressure effect. And a small seal gap 30 is formed between the stationary ring 28 and the stationary ring 28. Only a small amount of CO _{2 in} the machine passes through the seal gap 30 and is discharged from the third flow path 11C to the leak discharge system 23 via the flow passage 31 formed between the retainer 26 and the shaft sleeve 24. Is done. Thus, by cabin CO ₂ leaks to the outside only trace amounts, the remaining of such a large portion of the CO ₂ from leaking to the outside, between the rotary shaft 13 and the housing 12 by a first seal structure 16 Sealed.

The second seal structure 17 is for preventing a small amount of CO ₂ that has passed through the seal gap 30 of the first seal structure 16 from leaking out of the machine other than the leak discharge system 23 as described above. . Since the configuration of the second seal structure 17 is the same as that of the first seal structure 16, the same reference numerals as those of the first seal structure 16 are used, and the description thereof is omitted. According to the second seal structure 17 constituted, among the small amount of CO ₂ which has passed through the seal gap 30 of the first seal structure 16, further part of the CO ₂ is the sealing gap of the second seal structure 17 By passing 30, most of the remaining CO ₂ is prevented from leaking out of the machine. A small amount of the CO _{2 that} has passed through the first seal structure 16 is discharged outside the apparatus through the third flow path 11C. Further, when the first seal structure 16 loses the seal function due to damage or the like, the second seal structure 17 replaces the seal function of the first seal structure 16 as a backup. In the present embodiment, a so-called tandem structure is provided by providing the second seal structure 17 in addition to the first seal structure 16. However, the second seal structure 17 is not an essential component of the present invention. It is good also as a structure provided with the structure 16 only.

The in-machine labyrinth 18 and the out-of-machine labyrinth 19 are so-called labyrinth seals used for sealing compressed gas. As shown in FIG. 1, the in-machine labyrinth 18 and the out-of-machine labyrinth 19 alternately form narrow portions and wide portions between the rotary shaft 13 and the housing 12. According to such a configuration, the CO ₂ pressure expands in the widened portion after the in-machine CO ₂ passes through the narrow portion, so that a pressure drop occurs in the CO ₂ , and the leaked gas gradually decreases by repeating this. It has become. A leak discharge system 23 is also connected to the fourth flow path 11 </ b> D provided between the second seal structure 17 and the outboard labyrinth 19 via the discharge pipe line 22. The in-machine labyrinth 18 and the out-of-machine labyrinth 19 are not indispensable components for the present invention, but may be installed on the inside of the first seal structure 16 and the outside of the second seal structure 17 as in the present embodiment. There are the following merits. The inboard labyrinth 18, the volume CO ₂ recycled to the first flow path 11A CO ₂ circulation system 21 through, because less than the volume of the cabin CO _2, it is possible to reduce the capacity of the later of the heater, the temperature Control time can be shortened. Further, by supplying nitrogen or air gas from the fifth flow path 11E between the outboard labyrinth 19, it is possible to prevent the lubricating oil of the bearing from entering the inside of the machine. Of course, the number and installation positions of the in-machine labyrinth 18 and the out-of-machine labyrinth 19 can be appropriately changed.

The CO ₂ circulation system 21 is for supplying repeatedly cabin CO ₂ with respect to the sealing gap 30 generated between the rotary ring 25 circulates cabin CO ₂ and the stationary ring 28. Here, FIG. 2 is an explanatory diagram showing a configuration of the CO ₂ circulation system 21. The CO ₂ circulation system 21 has a supply pipe extending from the inside of the machine to a predetermined location of a circulation pipe line 20 having one end connected to the first flow path 11A of the housing 12 shown in FIG. 1 and the other end connected to the second flow path 11B. One end of the path 32 is connected, and various components are installed at various locations of the circulation piping 20 and the supply piping 32.

As shown in FIG. 2, the circulation piping 20 has a CO ₂ flow indicated by an arrow in the figure from the connection point to the first flow path 11 </ b> A to the connection point to the second flow path 11 </ b> B. A first filter unit 33, a circulation pump 34, a check valve 35, a second filter unit 36, a temperature control device 37, a flow meter 38, a pressure gauge 39, and a thermometer 40 are installed in this order.

The first filter unit 33 is installed in the circulation pipeline 20 to remove foreign matter from CO ₂ , a preliminary filter 33b that functions in a preliminary manner when the filter 33a is clogged, and the filter 33a. And a differential pressure gauge 33c for measuring the pressure difference between the upstream position and the downstream position. The second filter unit 36 also includes a filter 36 a, a spare filter 36 b, and a differential pressure gauge 36 c, and the function of each component is the same as that of each component of the first filter unit 33.

The circulation pump 34 forcibly circulates CO ₂ along the circulation pipeline 20. The check valve 35 is a valve having a function of keeping the flow of CO ₂ in the circulation pipeline 20 constant at all times and preventing backflow.

The temperature control device 37 arbitrarily adjusts the temperature of CO ₂ flowing through the circulation pipeline 20. As shown in FIG. 2, the temperature control device 37 includes a heat exchanger 37a that lowers the temperature of CO ₂ by exchanging heat with cooling water, and a heater that heats CO ₂ and raises its temperature. 37b. The operation of the temperature control device 37 is controlled by the control unit C. Although not shown in detail in FIG. 2, the control unit C controls not only the operation of the temperature control device 37 but also the operation of each part constituting the dry gas seal structure 10. Furthermore, the heater 37b may use a component provided in the dry gas seal structure 10 for another purpose as a heat source. Specifically, the circulating pump loss generated in the circulating pump 34 or the lubricating oil pump loss generated in the lubricating oil pump 15 shown in FIG. 1 is converted into thermal energy, and this thermal energy is used as a heat source for the heater 37b. May be. The heat source of the heater 37b is not limited to the circulation pump 34 and the lubricating oil pump 15, and various pumps installed in the dry gas seal structure 10 can be used for other purposes. According to such a configuration, as compared with the case where the dedicated heater 37b is provided, there is an advantage that the cost can be reduced because the dedicated heater 37b is unnecessary and the running cost is not required. Moreover, the heat exchanger 37a is not indispensable as a structure of the temperature control apparatus 37, and the temperature control apparatus 37 should just have the heater 37b at least.

The flow meter 38 measures the flow rate of CO ₂ circulating through the circulation pipeline 20. The pressure gauge 39 measures the pressure of CO ₂ in the vicinity of the connection point to the second flow path 11B. The temperature gauge 40 is to measure the temperature of the CO ₂ in the vicinity of the connection into the second flow path 11B.

On the other hand, as shown in FIG. 2, a pressure regulating valve 41 and a check valve 42 are installed in the supply pipe line 32 in order in the CO ₂ flow direction. The pressure adjustment valve 41 is a valve that can arbitrarily adjust the supply pressure of CO ₂ by adjusting the degree of opening and closing of the supply piping 32. On the other hand, the check valve 42 is a valve having a function of always maintaining the flow of CO ₂ in the supply piping 32 in a certain direction and preventing backflow, and CO ₂ circulating through the circulation piping 20 is supplied to the supply piping 32. Prevents inflow.

The leak discharge system 23 is for discharging a small amount of CO ₂ that has passed through the seal gap 30 of the first seal structure 16 to the outside of the apparatus. Here, FIG. 3 is a schematic diagram showing the configuration of the leak discharge system 23. In the leak discharge system 23, a discharge pipe line 22 having one end connected to the third flow path 11 </ b> C of the housing 12 shown in FIG. 1 is drawn out to the outside of the apparatus, and various components are installed in various places of the discharge pipe line 22. It is a thing.

As shown in FIG. 3, a thermometer 43, a pressure gauge 44, a flow meter 45, and a back pressure valve 46 are installed in the discharge pipe line 22 in order from the third flow path 11 </ _b > C toward the CO ₂ flow direction.

The thermometer 43 measures the temperature of CO ₂ in the vicinity of the connection location to the third flow path 11C shown in FIG. Further, the pressure gauge 44 measures the pressure of CO ₂ in the vicinity of the connection location to the third flow path 11C. The flow meter 45 measures the flow rate of CO ₂ flowing through the discharge pipe line 22. Further, the back pressure valve 46 is a valve for keeping the pressure of CO ₂ upstream from itself constant. That is, when the upstream pressure becomes equal to or higher than the set value, the back pressure valve 46 keeps the upstream pressure constant by reducing the pressure through CO ₂ .

Next, a procedure for starting the CO ₂ injection pump that employs the dry gas seal structure 10 according to the first embodiment will be described. 4 and 5 are flowcharts showing the flow of processing performed by the control unit C included in the CO ₂ injection pump at startup.

When starting the CO ₂ injection pump, first, the control unit C supplies CO ₂ in a gas state to the supply piping 32 (S1). Then, it is determined whether or not there is leakage of CO ₂ gas from various places of the piping, specifically, the circulation piping path 20, the supply piping path 32, and the discharge piping path 22 (S2). As a result, when it is determined that there is a leakage of CO ₂ gas (S2: Yes), this is notified to the user (S3), and it waits until there is no leakage. The user who has received the notification determines whether or not there is a CO ₂ gas leak by, for example, determining whether or not bubbles are produced by applying soapy water to the joint portion of the pipe. Specific means for notifying the user includes a method of displaying a warning on a display screen and a method of generating a warning sound from a speaker, although details are not shown in the figure.

On the other hand, when it is determined that there is no CO ₂ gas leakage (S2: No), the control unit C determines whether the seal leak amount is within an allowable range (S4). That is, the control unit C detects the measurement value of the flow meter 45 installed in the discharge pipe line 22 shown in FIG. 3, thereby causing the amount of seal leak, that is, CO ₂ leaking from the seal gap 30 of the first seal structure 16. Detect the amount of. Then, it is determined whether or not the detected seal leak amount is within a range allowable as the seal leak amount in a state where the rotation of the rotary shaft 13 is stopped. As a result, when it is determined that the seal leak amount is not within the allowable range (S4: No), the control unit C notifies the user (S5) and waits until the seal leak amount falls within the allowable range. In this case, there is a possibility that CO ₂ is leaking from the stationary ring 28, the rotating ring 25 or the like. Take appropriate measures such as replacement. On the other hand, when it is determined that the seal leak amount is within the allowable range (S4: Yes), the control unit C proceeds to the next step.

Next, the control unit C raises the temperature of the machine until the circulation pump 34 installed in the circulation pipeline 20 shown in FIG. 2 can be activated, specifically until the CO _{2 in the} machine reaches a supercritical state. The pressure is increased (S6). Subsequently, the control unit C activates the circulation pump 34 (S7). Furthermore, the control unit C detects the measurement value of the flow meter 38 installed in the circulation pipeline 20 shown in FIG. 2, and the circulation pump 34 so that the flow rate of CO ₂ circulating through the circulation pipeline 20 becomes a predetermined flow rate. Is appropriately adjusted (S8). Thus, by setting the flow rate of CO ₂ to a predetermined flow rate or more, CO ₂ flowing from the circulation pipe line 20 to the second flow path 11B is also on the inlet side of the sealing gap 30 of the first seal structure 16, inboard Since a sufficient amount also flows on the labyrinth 18 side, the inlet portion of the seal gap 30 can be sufficiently heated as will be described later, and foreign matter or the like enters from the inboard labyrinth 18 side toward the first seal structure 16. Can be prevented.

  Next, the control unit C detects the measured value of the differential pressure gauges 33c and 36c of the first filter unit 33 and the second filter unit 36 installed in the circulation pipe line 20 shown in FIG. The pressure difference between the upstream side and the downstream side is detected across the filters 33a and 36a. Then, it is determined whether or not the detected filter differential pressure has reached a predetermined filter exchange differential pressure (S9). As a result, when it is determined that the filter differential pressure has reached the filter replacement differential pressure (S9: Yes), the control unit C displays on a display screen (not shown) to indicate that the filter 33a should be replaced. The user is notified (S10) and waits until the filter differential pressure falls below the filter exchange differential pressure. The user who has received the notification performs appropriate measures such as switching to the spare filters 33b and 36b or replacing the filters 33a and 36a with new ones.

On the other hand, when the control unit C determines that the filter differential pressure has not yet reached the filter replacement differential pressure (S9: No), the controller C subsequently heats the inlet portion of the seal gap 30 of the first seal structure 16 to a predetermined temperature. (S11). That is, the control unit C controls the temperature adjustment device 37 shown in FIG. 2 so that the inlet portion of the seal gap 30 of the first seal structure 16 is heated to CO ₂ flowing from the second flow path 11B and reaches a predetermined temperature. The operation of the heat exchanger 37a and the heater 37b to be configured is controlled. In the present invention, the “inlet portion of the seal gap 30” means the vicinity of the most upstream portion of the seal gap 30 in the CO ₂ flow direction, and the rotating ring 25, the stationary ring 28, the shaft sleeve 24, and the retainer. 26 and the housing 12 are included.

Here, FIG. 6 and FIG. 7 are explanatory diagrams for explaining the effect of heating the inlet portion of the seal gap 30. When the inlet portion of the seal gap 30 is heated, the temperature of CO ₂ when passing through the seal gap 30 rises. Then, as shown in FIG. 6, when the temperature of CO ₂ is increased, for example, from 50 ° C. to 60 ° C., the CO ₂ is decompressed during passage of the sealing gap 30, the state of the CO ₂ is to the gaseous state from the supercritical state And change. Therefore, the physical properties of CO ₂ do not change drastically compared with the case where the gas phase changes from the supercritical state to the gas-liquid two phase as described above. Therefore, the behavior of the stationary ring 28 is stable, and the seizure does not occur due to the contact between the stationary ring 28 and the rotating ring 25. Furthermore, as shown in FIG. 7, when the temperature of CO ₂ rises from, for example, 40 ° C. to 60 ° C., the viscosity of CO ₂ decreases. As a result, the amount of viscous heat generated when CO ₂ passes through the seal gap 30 is reduced, and excessive thermal deformation such as contact between the rotating ring 25 and the stationary ring 28 does not occur.

Next, the control unit C increases the supply pressure of CO _{2 to} a predetermined pressure (S12). That is, the control part C raises the supply pressure of CO ₂ by controlling the operation of the pressure regulating valve 41 installed in the supply pipeline 32 shown in FIG. The control unit C, together with this, CO ₂ in the seal at the inlet portion of the gap 30 so that CO ₂ is a predetermined pressure, the outlet portion of the sealing gap 30 of the first seal structure 16 of the second seal structure 17 Is controlled by controlling the operation of the back pressure valve 46 installed in the discharge pipe line 22.

Thereafter, the control unit C determines whether or not the temperature of the outlet portion of the seal gap 30 of the first seal structure 16 is below freezing (S13). That is, the control unit C detects the temperature of the outlet portion of the seal gap 30 of the first seal structure 16 by detecting the measurement value of the thermometer 43 installed in the discharge pipe line 22 shown in FIG. When the detected temperature is below freezing (S13: Yes), the control unit C further heats the inlet portion of the seal gap 30 (S14). That is, the control unit C is configured to adjust the temperature control device shown in FIG. 2 so that the inlet portion of the seal gap 30 of the first seal structure 16 is heated by CO ₂ flowing from the second flow path 11B and the temperature thereof further increases. The operation of 37 is controlled.

Thus, if the temperature of the inlet portion of the seal gap 30 of the first seal structure 16 is prevented from becoming below freezing point, the moisture in the atmosphere does not become ice at the outlet portion of the seal gap 30. Therefore, the problem that the seal gap 30 is blocked by ice and the problem that the seal surface 25a of the rotary ring 25 and the seal surface 28a of the stationary ring 28 are damaged by ice can be prevented. If the temperature of the CO ₂ cannot be further increased due to the performance of the temperature control device 37, details are not shown in the figure, but the gas heated to the outlet portion of the seal gap 30 of the first seal structure 16 is not shown. For example, the outlet portion of the seal gap 30 may not be below freezing point by spraying.

Next, the controller C determines again whether or not the seal leak amount is within the allowable range (S15). That is, the control unit C detects the measurement value of the flow meter 45 installed in the discharge pipe line 22 shown in FIG. 3, thereby causing the amount of seal leak, that is, CO ₂ leaking from the seal gap 30 of the first seal structure 16. Detect the amount of. Then, it is determined whether or not the detected seal leak amount is within a range allowable as the seal leak amount in a state where the rotation of the rotary shaft 13 is stopped. As a result, when it is determined that the seal leak amount is not within the allowable range (S15: No), the control unit C notifies the user (S16) and waits until the seal leak amount falls within the allowable range. The user who has received the notification performs appropriate measures so that the seal leak amount falls within the allowable range.

Here, as an appropriate measure, when it is determined that the seal leak amount is outside the allowable range, particularly when the seal leak amount is zero, the user has the CO ₂ air volume at the exit portion of the seal gap 30. Confirm whether or not. As a result, when there is no air volume of CO ₂ at the outlet portion, from elsewhere in the sealing gap 30, for example, CO ₂ from where the O-ring 29 is damaged there is a possibility that leaked to the outside. In this case, the user takes measures such as repair after finding the leaking portion. On the other hand, if a location where CO ₂ leaks outside the seal gap 30 cannot be found, the supply of CO ₂ is stopped, and it is confirmed whether or not the pressure inside the device decreases. As a result, when the pressure in the machine does not decrease, the seal gap 30 may be closed, and thus a measure such as hand turning is performed. In addition, the user checks whether a failure has occurred in various sensors as other measures. On the other hand, when it is determined that the seal leak amount is outside the allowable range, particularly when the seal leak amount is excessive, the user inspects the rotary ring 25 and the stationary ring 28 and then performs measures such as repair and replacement. Apply.

On the other hand, when it is determined that the seal leak amount is within the allowable range (S15: Yes), the control unit C starts rotation of the rotary shaft 13 by starting a motor (not shown), and the rotation speed is set to a predetermined speed. (S17). At this time, the control part C accelerates rapidly until the rotating shaft 13 reaches a predetermined minimum rotational speed or more. Further, as the rotational speed of the rotary shaft 13 increases, the temperature of the seal gap 30 increases due to CO ₂ agitation loss or viscous heat generation in the seal gap 30. Therefore, the control unit C appropriately controls the operation of the temperature adjustment device 37 shown in FIG. 2 so that the temperature of the inlet portion of the seal gap 30 can be maintained at an appropriate temperature regardless of the temperature increase. And the control part C stops the operation | movement of the heater 37b which comprises the temperature control apparatus 37 in the stage where the temperature of the seal gap 30 fully raised finally by stirring loss, viscous heat_generation | fever, etc. Further, the controller C measures the shaft vibration of the rotating shaft 13 as the rotating shaft 13 starts to be driven, and if the measured shaft vibration exceeds a predetermined seal allowable value alarm value, the rotating shaft 13 rotates. And adjust the balance of the rotary shaft system so that the shaft vibration is within the allowable seal value.

Next, the control unit C determines again whether or not the seal leak amount is within the allowable range (S18). That is, the control unit C detects the measurement value of the flow meter 45 installed in the discharge pipe line 22 shown in FIG. 3, thereby causing the amount of seal leak, that is, CO ₂ leaking from the seal gap 30 of the first seal structure 16. Detect the amount of. Then, it is determined whether or not the detected seal leak amount is within a range allowed as the seal leak amount when the rotary shaft 13 is in a rotating state. As a result, when it is determined that the seal leak amount is not within the allowable range (S18: No), the control unit C notifies the user (S19) and waits until the seal leak amount falls within the allowable range. The user who has received the notification performs appropriate measures so that the seal leak amount falls within the allowable range.

Here, as an appropriate measure, when it is determined that the seal leak amount is outside the allowable range, particularly when the seal leak amount is zero, the user has the CO ₂ air volume at the exit portion of the seal gap 30. Confirm whether or not. As a result, when there is no CO ₂ air volume at the exit portion, the user immediately stops the rotation of the rotary shaft 13. This is because, when the rotary shaft 13 is rotating, if the seal gap 30 is not generated, there is a possibility that seizure may occur due to the contact between the seal surface 25a of the rotary ring 25 and the seal surface 28a of the stationary ring 28. is there. Then, after the rotary shaft 13 stops, the control unit C detects the seal leak amount again, and the detected seal leak amount is allowed as the seal leak amount in a state where the rotation of the rotary shaft 13 is stopped. Check if it is inside. On the other hand, when it is determined that the seal leak amount is outside the allowable range, particularly when the seal leak amount is excessive, the user immediately stops the rotation of the rotary shaft 13 and inspects the rotary ring 25 and the stationary ring 28. Above, take measures such as repair and replacement.

Finally, the control unit C decreases the rotational speed of the circulation pump 34 installed in the circulation pipeline 20 shown in FIG. 2 and circulates CO ₂ supplied from the inside of the machine through the circulation pipeline 20. And finally, the control part C stops the circulation pump 34 and performs rated operation (S20).

  Next, the configuration of the dry gas seal structure according to the second embodiment will be described. FIG. 8 is a schematic longitudinal sectional view showing the dry gas seal structure 50 of the present embodiment. The dry gas seal structure 50 is different from the dry gas seal structure 10 of the first embodiment in that the configuration of the rotary ring 51 of the first seal structure 16 is different and the CO2 circulation system 21 is not provided. . Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIG. 1 are used, and description thereof is omitted here.

The rotary ring 51 of the first seal structure 16 houses a heater 52 therein, and the operation of the heater 52 is controlled by a control unit (not shown). Then, the control unit heats the inlet portion of the seal gap 30 of the first seal structure 16 to a predetermined temperature by turning on the heater 52 before starting the driving of the rotary shaft 13. According to such a configuration, space saving can be achieved as compared with the first embodiment. That is, in the configuration in which the inlet portion of the seal gap 30 of the first seal structure 16 is heated by supplying heated CO ₂ as in the first embodiment, a space for installing the CO ₂ circulation system 21 outside the apparatus is necessary. It is. On the other hand, in this embodiment, it is possible to save space because the CO ₂ circulation system 21 does not need to be installed outside the apparatus.

  FIG. 9 is a view showing a modification of the present embodiment. In the modification shown in FIG. 9A, the heater 52 is accommodated in the stationary ring 53. On the other hand, in the modification shown in FIG. 9B, the heater 52 is accommodated in the rotating ring 51 and the heater 52 is accommodated in the stationary ring 53. And before starting the drive of the rotating shaft 13, by turning on these heaters 52, the inlet portion of the seal gap 30 of the first seal structure 16 is heated to a predetermined temperature. Since the rotary ring 51 is generally made of silicon carbide, which is a material that is not easily thermally deformed, it is preferable to accommodate the heater 52 in the rotary ring 51 because thermal deformation can be suppressed. is there.

Next, the configuration of the dry gas seal structure according to the third embodiment will be described. FIG. 10 is a schematic longitudinal sectional view showing the dry gas seal structure 60 of the present embodiment. The dry gas seal structure 60 differs from the dry gas seal structure 10 of the first embodiment in that the configuration of the housing 61 is different and the CO ₂ circulation system 21 is not provided. Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIG. 1 are used, and description thereof is omitted here.

In the housing 61 of this embodiment, a heater 62 is accommodated in the periphery of the second flow path 11B. And before starting the drive of the rotating shaft 13, this heater 62 is turned ON, and the entrance part of the seal gap 30 of the 1st seal structure 16 is heated to predetermined temperature. According to such a configuration, as in the second embodiment, there is an advantage that the space can be saved because the space for installing the CO ₂ circulation system 21 outside the apparatus is unnecessary.

  Next, the configuration of the dry gas seal structure according to the fourth embodiment will be described. FIG. 11 is a schematic longitudinal sectional view showing the dry gas seal structure 70 of the present embodiment, and is an enlarged view of the periphery of the seal gap 30. Compared with the dry gas seal structure 10 of the first embodiment, the dry gas seal structure 70 differs in the shape of the flow passage 71 formed between the second flow path 11B and the inlet portion of the seal gap 30. Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIG. 1 are used, and description thereof is omitted here.

In the present embodiment, the peripheral portion of the rotary ring 25 in the shaft sleeve 72 is formed with a larger diameter compared to the first embodiment. As a result, the flow passage 71 through which CO ₂ flows inside the housing 12 is formed such that the portion immediately before the seal gap 30 of the first seal structure 16 is narrower than the other portions. According to such a configuration, it is necessary to heat the inlet portion of the seal gap 30 in the same manner as in the first to third embodiments before starting the driving of the rotating shaft 13, but after starting the driving of the rotating shaft 13. The temperature of the inlet portion of the seal gap 30 of the first seal structure 16 rises due to agitation loss when CO ₂ passes through this narrow portion. Therefore, after the drive of the rotary shaft 13 is started, the heaters 37b, 62, etc. used to heat the inlet portion of the seal gap 30 before the drive start can be turned off. As a result, the cost can be reduced by reducing the running cost of the heaters 37b and 62.

FIG. 12 is a view showing a modification of the present embodiment. In this modification, the peripheral portion of the second flow path 11B in the housing 73 is formed thicker than the other portions. Thus, in the flow passage 71 through which CO ₂ flows in the housing 73, the portion immediately before the seal gap 30 of the first seal structure 16 is formed narrower than the other portions. According to such a configuration, as in the fourth embodiment, after the driving of the rotary shaft 13 is started, the heaters 37b, 62, etc. used to heat the inlet portion of the seal gap 30 before the driving is turned off. can do. As a result, the cost can be reduced by reducing the running cost of the heaters 37b and 62.

  The various shapes, combinations, operation procedures, and the like of the constituent members shown in the above-described embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Dry gas seal structure 12 ... Housing 13 ... Rotating shaft 20 ... Circulation piping 25 ... Rotating ring 28 ... Static ring 30 ... Seal gap 37 ... Temperature control apparatus C ... Control part

Claims (6)

A housing for containing supercritical fluid;
A rotating shaft provided through the housing and driven to rotate;
A rotating ring that surrounds the rotating shaft and rotates integrally therewith;
A stationary ring that is provided in the housing, abuts on the entire circumference of the rotating ring when the rotating shaft is stopped, and is stationary with a seal gap formed between the rotating ring and the rotating ring;
A pipe for supplying a part of the fluid stored in the housing to the inlet portion of the seal gap;
A temperature control device for adjusting the temperature of the fluid flowing through the pipe line;
A controller that controls the operation of the temperature control device so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotary shaft;
Equipped with a,
A circulation pump that circulates the fluid supplied to the inlet portion of the seal gap and supplies the fluid again to the inlet portion of the seal gap is provided in the pipe line,
The temperature control device includes a heater that heats the fluid flowing through the piping, and the heat source of the heater supplies lubricating oil to the circulating pump or a bearing that rotatably supports the rotating shaft. A dry gas seal structure characterized by being one of oil pumps . A housing for containing supercritical fluid;
A rotating shaft provided through the housing and driven to rotate;
A rotating ring that surrounds the rotating shaft and rotates integrally therewith;
A stationary ring that is provided in the housing, abuts on the entire circumference of the rotating ring when the rotating shaft is stopped, and is stationary with a seal gap formed between the rotating ring and the rotating ring;
A pipe for supplying a part of the fluid stored in the housing to the inlet portion of the seal gap;
A temperature control device for adjusting the temperature of the fluid flowing through the pipe line;
A controller that controls the operation of the temperature control device so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotary shaft;
With
The dry gas seal structure according to claim 1, wherein the flow passage formed inside the housing and through which the fluid in the supercritical state flows is formed with a narrower portion immediately before the seal gap than other portions . 3. The dry gas seal structure according to claim 2 , wherein a circulation pump that circulates the fluid supplied to the inlet portion of the seal gap and supplies the fluid again to the inlet portion of the seal gap is provided in the pipe line. . The temperature control device includes a heater that heats the fluid flowing through the piping, and the heat source of the heater supplies lubricating oil to the circulating pump or a bearing that rotatably supports the rotating shaft. The dry gas seal structure according to claim 3 , wherein the dry gas seal structure is any one of oil pumps. A housing for containing supercritical fluid;
A rotating shaft provided through the housing and driven to rotate;
A rotating ring that surrounds the rotating shaft and rotates integrally therewith;
A stationary ring that is provided in the housing, abuts on the entire circumference of the rotating ring when the rotating shaft is stopped, and is stationary with a seal gap formed between the rotating ring and the rotating ring;
A heater provided in at least one of the rotating ring and the stationary ring;
A controller that controls the operation of the heater so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotary shaft;
With
The dry gas seal structure according to claim 1, wherein the flow passage formed inside the housing and through which the fluid in the supercritical state flows is formed with a narrower portion immediately before the seal gap than other portions . A housing for containing supercritical fluid;
A rotating shaft provided through the housing and driven to rotate;
A rotating ring that surrounds the rotating shaft and rotates integrally therewith;
A stationary ring that is provided in the housing, abuts on the entire circumference of the rotating ring when the rotating shaft is stopped, and is stationary with a seal gap formed between the rotating ring and the rotating ring;
A heater provided immediately before the seal gap in the housing;
A controller that controls the operation of the heater so that the inlet portion of the seal gap is heated to a predetermined temperature before driving the rotary shaft;
With
The dry gas seal structure according to claim 1, wherein the flow passage formed inside the housing and through which the fluid in the supercritical state flows is formed with a narrower portion immediately before the seal gap than other portions .

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