JP2012241784A - Mechanical seal device for high-pressure fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably reduce running costs and initial costs without requiring a pressure unit by charging/filling an intermediate area with a seal liquid without circulating and supplying the seal liquid.SOLUTION: In a mechanical seal device for a high-pressure fluid, an intermediate area C is formed between a first mechanical seal 1a at a sealed fluid area side and a second mechanical seal 2a at an atmospheric area side and the intermediate area C is charged/filled with a seal liquid L of lower pressure than a sealed fluid area A. The mechanical seal device includes a pressure equalizer 4a configured by partitioning the inside of a cylinder 41 into a low-pressure fluid space 43b and a high-pressure fluid space 43a of which the piston pressure receiving area is smaller than that of the low-pressure fluid space 43b, by a piston 42. The intermediate area C is communicated and connected with the low-pressure fluid space 43b of the pressure equalizer 4a and the sealed fluid area A is communicated and connected with the high-pressure fluid space 43a of the pressure equalizer 4a, so that the pressure ratio of the sealed fluid area A and the intermediate area C can be kept fixed.

Description

  The present invention relates to a mechanical seal device used as a shaft sealing means of a rotating device (for example, a process pump, a blower, a compressor, a turbine, a stirrer, etc.) that handles high-pressure fluid, and a plurality of end-contact mechanical seals Are arranged in series in the axial direction, and the present invention relates to a mechanical seal device for high pressure fluid configured to seal a sealed fluid region and an atmospheric region through an intermediate region formed between mechanical seals.

  As this type of mechanical seal device, a pair of end-face contact type mechanical seals are arranged in series in the axial direction, and a sealing liquid (sealing) having a pressure different from the pressure of the sealed fluid region is formed in an intermediate region formed between the two mechanical seals. And a sealed fluid region and an atmospheric region are shielded and sealed via an intermediate region. Conventionally, a sealed fluid region is provided in the intermediate region. A tandem seal configured to circulate and supply a lower pressure sealing liquid (see, for example, Patent Document 1) or a double seal configured to circulate and supply a higher pressure sealing liquid from the sealed fluid region to the intermediate region (for example, (See Patent Document 2).

JP 2010-223332 A Japanese Utility Model Publication No. 63-119969

  However, in such a conventional mechanical seal device, it is necessary to attach a pressure unit in order to circulate and supply the seal liquid maintained at a predetermined pressure to the intermediate region. Such a pressure unit requires a high-performance circulation pump or the like and is extremely expensive. Therefore, there is a problem that the initial cost and running cost of the mechanical seal device are increased by attaching the pressure unit.

  In addition, the pressure relationship between the sealed fluid region and the intermediate region may be reversed due to pressure fluctuations in the sealed fluid region, and a reverse pressure may act on the mechanical seal. There was a problem that the pressure action could not be properly handled and a good sealing function could not be exhibited. In order to cope with the reverse pressure, an advanced and expensive pressure control system is required, and the cost including the maintenance cost is significantly increased.

  Furthermore, when the circulation pump of the pressure unit is stopped due to a power failure or the like, there is a problem that the pressure in the intermediate region is not properly maintained and the seal is damaged due to overload.

  An object of the present invention is to provide a practical high-pressure fluid mechanical seal device that can exhibit a good sealing function without causing such problems.

  The present invention is configured such that a plurality of end face contact type mechanical seals are arranged in series in the axial direction, and the sealed fluid region and the atmospheric region are shield-sealed through an intermediate region formed between the mechanical seals. In the high-pressure fluid mechanical seal device, in order to achieve the above-mentioned purpose, each intermediate region is filled and sealed with a sealing liquid having a pressure different from the pressure of the intermediate region adjacent thereto or the sealed fluid region. The number of pressure equalizers equal to the number of intermediate regions formed by partitioning the space for low pressure fluid and the space for high pressure fluid whose piston pressure receiving area is smaller than the space for low pressure fluid is provided by a piston in which the sealed space of Each intermediate region is connected to one of the space for low pressure fluid and the space for high pressure fluid of each pressure equalizer and is connected to the intermediate region adjacent to the intermediate region or the sealed fluid region. Connect to the other of the low pressure fluid space and the high pressure fluid space so that the pressure ratio between each intermediate region and the adjacent intermediate region or sealed fluid region is kept constant. This is a proposal. In the present invention, the pressure means a gauge pressure based on the atmospheric pressure.

  As a preferred first embodiment of such a mechanical seal device for high-pressure fluid, a sealed fluid is provided in an intermediate region formed between a first mechanical seal on the sealed fluid region side and a second mechanical seal on the atmospheric region side. A tandem seal filled and sealed with a lower pressure sealant than the region is proposed. In this tandem seal, the intermediate region is connected to the low pressure fluid space of the pressure equalizer and the sealed fluid region is connected to the high pressure fluid space of the pressure equalizer so that the sealed fluid region and the intermediate region are connected. The pressure ratio is maintained constant.

  As a second preferred embodiment of the mechanical seal for high-pressure fluid of the present invention, the second mechanical seal located between the first mechanical seal on the sealed fluid region side, the third mechanical seal on the atmospheric region side, and both mechanical seals is used. A triple seal is proposed in which the first and second mechanical seals form a double seal structure and the second and third mechanical seals form a tandem seal structure. In this triple seal, the first intermediate region formed between the first and second mechanical seals is filled and sealed with a first seal liquid having a pressure higher than the fluid to be sealed, and between the second and third mechanical seals. The second intermediate region to be formed is filled and sealed with a second sealing liquid having a pressure lower than that of the first intermediate region, and the first intermediate region is connected in communication with the high pressure fluid space of the first pressure equalizer and the high pressure of the second pressure equalizer. The fluid to be sealed is connected to the fluid space, the sealed fluid region is connected to the low pressure fluid space of the first pressure equalizer, and the second intermediate region is connected to the low pressure fluid space of the second pressure equalizer. The pressure ratio between the region and the first intermediate region and the pressure ratio between the two intermediate regions are each kept constant.

  As a preferred third embodiment of the mechanical seal for high-pressure fluid of the present invention, the second mechanical seal located between the first mechanical seal on the sealed fluid region side, the third mechanical seal on the atmospheric region side, and both mechanical seals is used. The mechanical seal is disposed so as to form a tandem seal structure, and the first intermediate liquid formed between the first and second mechanical seals is filled and sealed with a first seal liquid having a pressure lower than the fluid to be sealed. A second intermediate region formed between the second and third mechanical seals is proposed by being filled and sealed with a second sealing liquid having a lower pressure than the first intermediate region. In this mechanical seal device, the first intermediate region is connected in communication with the low pressure fluid space of the first pressure equalizer and is connected in communication with the high pressure fluid space of the second pressure equalizer, and the sealed fluid region is connected in the first pressure equalizing space. A pressure ratio between the sealed fluid region and the first intermediate region and a pressure in both intermediate regions are communicated with the high pressure fluid space of the pressure device and the second intermediate region is communicated with the low pressure fluid space of the second pressure equalizer. Each ratio is configured to be kept constant.

  Furthermore, in the mechanical seal device for high pressure fluid of the present invention, it is preferable that a detector capable of detecting the moving position or moving amount of the piston is attached to the pressure equalizer.

  According to the mechanical seal device for high-pressure fluid of the present invention, since the sealing liquid (sealing liquid or buffer liquid) is filled and sealed without circulating supply to the intermediate region, no pressure unit is required, running cost and initial Cost can be greatly reduced. In addition, by connecting the sealed fluid area and the intermediate area adjacent thereto through a pressure equalizing device, when there are a plurality of intermediate areas, each intermediate area and the intermediate area adjacent thereto are equalized. By connecting with a pressure device, special pressure control is possible even when used under conditions in which the sealed fluid region fluctuates or when an unexpected situation occurs in which the pressure in the intermediate region fluctuates. Without requiring a system, the pressure relationship between the sealed fluid region and the intermediate region adjacent thereto and the pressure relationship (pressure ratio) between each intermediate region and the intermediate region adjacent thereto can be properly maintained. A good mechanical seal function can be exhibited. In addition, since no pressure unit is required, there is no possibility of troubles that may cause seal damage due to overload even in the event of an emergency such as a power failure.

FIG. 1 is a longitudinal sectional side view of a main part showing an example of a mechanical seal device for high pressure fluid according to the present invention. FIG. 2 is a system diagram showing the overall configuration of the mechanical seal device. FIG. 3 is a longitudinal side view of a main part showing a modification of the mechanical seal device for high pressure fluid according to the present invention. FIG. 4 is a system diagram showing the overall configuration of the mechanical seal device. FIG. 5 shows another modification of the mechanical seal device for high-pressure fluid according to the present invention, and is a system diagram showing the overall configuration of the mechanical seal device. FIG. 6 is a longitudinal side view showing an example of a pressure equalizer used for each high-pressure fluid mechanical seal device shown in FIGS.

  Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.

  That is, FIG. 1, FIG. 2 and FIG. 6 show a first embodiment of a high-pressure mechanical seal device according to the present invention, and FIG. 1 is a longitudinal side view of a main part of the mechanical seal device. FIG. 6 is a system diagram showing the overall configuration of the mechanical seal device, and FIG. 6 is a longitudinal side view showing an example of a pressure equalizer used for the mechanical seal.

  The mechanical seal device for high pressure fluid (hereinafter referred to as “first mechanical seal device”) shown in FIGS. 1 and 2 is a vertical rotating device (for example, a vertical axis) that handles liquid high pressure fluid (for example, high pressure water) K First and second mechanical seals 1a, which are used as shaft sealing means of a high-pressure pump or the like, in which a sealed fluid region A which is an in-machine region and an atmospheric region B which is an out-of-machine region are arranged in series in the axial direction. 2a is a tandem seal configured to be shield-sealed, and is connected to a sealed fluid region A and an intermediate region C formed between both mechanical seals 1a and 2a via a pressure equalizing device 4a. C is filled and sealed with a sealing liquid L slightly lower than the pressure of the sealed fluid region A, that is, the pressure of the high-pressure fluid (sealed fluid) K to be sealed, so that the sealed fluid region A and the atmospheric region B are intermediate regions. Is configured to seal through. Although the sealing solution L is selected according to the sealing conditions, Shimizu in this example is used.

  As shown in FIG. 1, the first mechanical seal 1 a is arranged on the stationary seal ring 11 fixed to the seal case 5 and the rotary shaft 6 that extends through the seal case 5 by being arranged on the sealed fluid region side (lower side). A rotary seal ring 12 held movably in the direction and a spring 13 that presses and urges the rotary seal ring 12 to the stationary seal ring 11, and the relative rotation of the sealed end faces as the opposed end faces of the seal rings 11, 12 is provided. An end face contact type mechanical seal configured to shield and seal the sealed fluid region A including the outer peripheral side region and the intermediate region C including the inner peripheral side region thereof by the sliding contact action. is there. The rotating shaft 6 includes a shaft body 6a and a sleeve 6b inserted and fixed to the shaft main body 6a by an appropriate sleeve fixing means (shrink ring in this example) 6c.

  The rotary seal ring 12 has a drive collar 12a connected to the base end portion, and is fitted and held on the sleeve 6b of the rotary shaft 6 through an O-ring 14 so as to be movable in the axial direction. A spring retainer 15 is fixed to the sleeve 6b of the rotary shaft 6 on the sealed fluid region side of the rotary seal ring 12, and is disposed near the sealed fluid region side (lower vicinity) of the spring retainer 15. Thus, the circulation ring 16 is fixed. The outer peripheral portion of the circulation ring 16 is configured as a cylindrical portion 16a protruding upward and close to the inner peripheral surface of the seal case 5, and the cylindrical portion 16a has a plurality of circulation holes 16b penetrating in the radial direction. Is formed. As shown in FIG. 1, the sealed fluid region A is provided with a first mechanical seal 1 that is a region on the outer peripheral side of a relative rotational sliding contact portion of both the sealing rings 11 and 12 by a circulation ring 16 having a labyrinth formed on the outer periphery. It is divided into an area (hereinafter referred to as “first flushing area”) A1 and other areas. Between the rotary seal ring 12 and the spring retainer 15, a spring 13 that biases the rotary seal ring 12 to press contact with the stationary seal ring 11 and a drive that prevents relative rotation of the rotary seal ring 12 with respect to the rotary shaft 6. A pin 17 is interposed.

  As shown in FIG. 1, the second mechanical seal 2 a is arranged in tandem with the first mechanical seal 1 a on the atmosphere region side (upper side) of the first mechanical seal 1 a and is fixed to the seal case 5. A rotating ring 22 disposed on the sealed fluid region side of the ring 21 and the stationary ring 21 and held on the rotating shaft 6 so as to be movable in the axial direction, and an idle ring 23 and a rotating ring held between both the rings 21 and 22. And a spring 24 that presses and urges 22 toward the stationary ring 21, and the outer periphery of the relative rotational sliding contact portion by the relative rotational sliding contact action of the sealing end surface that is the opposed end surface of the rotational ring 22 and the idle ring 23. This is an end surface contact type mechanical seal (floating ring type mechanical seal) configured to shield and seal the intermediate region C including the side region and the atmospheric region B including the inner peripheral region.

  The rotary ring 22 has a drive collar 22a connected to the base end portion, and is fitted and held on the sleeve 6b of the rotary shaft 6 through an O-ring 25 so as to be movable in the axial direction. A spring retainer 26 is fitted and fixed to the sleeve 6 b of the rotary shaft 6 on the sealed fluid region side (lower side) of the rotary ring 22. A circulation ring 27 is integrally formed at the base end portion (end portion on the sealed fluid region side) of the spring retainer 26. The outer peripheral portion of the circulation ring 27 is configured as a cylindrical portion 27a that protrudes upward and is close to the inner peripheral surface of the seal case 5. The cylindrical portion 27a has a plurality of circulation holes 27b that pass through the cylindrical portion 27a in the radial direction. Is formed. The intermediate region C includes a second mechanical seal 2a disposition region (hereinafter referred to as a “second flushing region”) C1 that is an outer peripheral side region of the relative rotational sliding contact portion between the rings 22 and 23 by the circulation ring 27 and the other regions. It is divided into areas. Between the rotary ring 22 and the spring retainer 26, there are interposed a spring 24 for urging the rotary ring 22 to press contact with the idle ring 23 and a drive pin 28 for preventing relative rotation of the rotary ring 22 with respect to the rotary shaft 6. It is disguised. The idle ring 23 is held between the stationary ring 21 and the rotating ring 22 by the urging force of the spring 24, and O-rings 29a and 29b are interposed between the stationary ring 21 and the seal case 5, respectively. Is loaded. An appropriate number of communication holes 23a and engagement holes penetrating the idle ring 23 in the axial direction are formed, and the drive pin 21a projecting from the stationary ring 21 is engaged with the engagement hole so as to be idle. The relative rotation of the ring 23 with respect to the stationary ring 21 (and the seal case 5) is prevented.

  The seal case 5 has a cylindrical shape having a circular inner peripheral surface, and as shown in FIGS. 1 and 2, a high-pressure fluid port 51a that opens to the sealed fluid region A and a low-pressure fluid port 51b that opens to the intermediate region C are formed. Has been. The high-pressure fluid port 51a is opened to the sealed fluid region A. In this example, as shown in FIG. 1, the high-pressure fluid port 51a is located at a suitable position in the sealed fluid region A excluding the first flushing region A1 and in the vicinity of the circulation ring 16. The low-pressure fluid port 51b is opened at an appropriate position in the second flushing region C1 and between the idle ring 23 and the circulation ring 27.

  Thus, as shown in FIGS. 1 and 2, the pressure ports 51a and 51b are connected in communication via the pressure equalizer 4a. The pressure equalizer 4a is connected to the piston in the cylinder 41 as shown in FIG. 42, and has the same structure as a general piston / cylinder.

  That is, the cylinder 41 is a cylindrical sealed container that extends in the vertical direction. The piston 42 is a disk-shaped member formed by connecting an upwardly extending piston rod 42 a to the center of the upper surface that is one end surface. By allowing the piston rod 42 a to penetrate and support the upper wall of the cylinder 41, It is loaded so that it can move forward and backward (movable in the axial direction). The contact portion between the piston 42 and the inner wall surface of the cylinder 41 and the contact portion between the piston rod 42a and the upper wall of the cylinder 41 through which the piston rod 42a penetrates are sealed by an O-ring so as to be relatively movable.

  The sealed space in the cylinder 41 is partitioned by the piston 42 into a high-pressure fluid space 43a where the piston rod 42a exists and a low-pressure fluid space 43b where the piston rod 42a does not exist. The area for receiving the fluid pressure in the working spaces 43a and 43b varies depending on the presence or absence of the piston rod 42a. That is, the piston pressure receiving area S2 in the low pressure fluid space 43b matches the internal space sectional area of the cylinder 41, but the piston pressure receiving area S1 in the high pressure fluid space 43a is determined from the internal space sectional area of the cylinder 41, that is, the piston pressure receiving area S2. The value is obtained by subtracting the cross-sectional area S3 of the piston rod 42a, which is smaller than the piston pressure receiving area S2 in the low pressure fluid space 43b.

  As shown in FIG. 6, the cylinder 41 has a high-pressure fluid port 41a that opens at the upper end of the high-pressure fluid space 43a and a low-pressure fluid port 41b that opens at the bottom of the low-pressure fluid space 43b. As shown, the high-pressure fluid port 51a and the low-pressure fluid port 51b formed in the seal case 5 are connected in communication. That is, the high-pressure fluid ports 41a and 51a are connected by a high-pressure fluid pipe 71a and the low-pressure fluid ports 41b and 51b are connected by a low-pressure fluid pipe 71b. A fluid (sealed fluid) K in the sealed fluid region A that is a high-pressure fluid is introduced into the low-pressure fluid piping 43b and a fluid (sealing fluid) L in the intermediate region C that is a low-pressure fluid from the low-pressure fluid pipe 71b. Has been introduced.

  When the pressure of the sealed fluid K is P1 and the pressure of the sealing liquid L is P2, in the pressure equalizer 4a, the pressures P1, P2 (P1> P2) on both sides of the piston 42 and the piston pressure receiving areas S1, S2 The relationship P1 · S1 = P2 · S2 is established between (S1 <S2) and Pascal's principle. That is, the ratio of the pressure P1 of the high-pressure fluid (sealed fluid) K to the pressure P2 of the low-pressure fluid (sealing fluid) L (hereinafter referred to as “pressure ratio”) P1 / P2 and the low pressure relative to the piston pressure receiving area S1 in the high-pressure fluid space 43a A relationship (P1 / P2 = S2 / S1) is established in which the ratio of the piston pressure receiving area S2 in the fluid space 43b (hereinafter referred to as “piston pressure receiving area ratio ξ”) S2 / S1 is equivalent. On the other hand, the piston pressure receiving area ratio ξ (= S2 / S1) can be arbitrarily set by changing only the cross-sectional area S3 of the piston rod 42a.

  Thus, in the pressure equalizer 4a, the piston pressure receiving area ratio ξ is the pressure of the sealed fluid K set at the design stage or the operation start stage of the first mechanical seal device (hereinafter referred to as “sealed fluid set pressure P1a”). And a pressure ratio P1a / P2a with respect to the pressure in the intermediate region C (hereinafter referred to as “sealing fluid set pressure P2a”) set lower by a predetermined pressure (slight pressure) (ξ = S2 / S1 = P1a / P2a). In the operation start stage (when P1 = P1a and P2 = P2a), as shown in FIG. It is set to be positioned at the “reference position”.

  Therefore, when the pressure P1 in the sealed fluid region A increases due to a change in the operating condition of the rotating equipment, or when the pressure P2 in the intermediate region C decreases due to leakage of seal liquid from the second mechanical seal 2a to the atmospheric region B, etc. 6B, the piston 42 moves in a direction to decrease the volume of the low-pressure fluid space 43b (for example, moves downward from the reference position (position shown in FIG. 6A)). The increased pressure corresponding to the volume reduction amount of the low pressure fluid space 43b is propagated from the low pressure fluid pipe 71b to the intermediate region C, and the pressure P2 in the intermediate region C increases. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P1 of the high-pressure fluid space 43a and the pressure P2 of the low-pressure fluid space 43b. P1 / P2 is equivalent to the piston pressure receiving area ratio ξ (= P1a / P2a) and does not change. That is, the pressure P1 in the sealed fluid region A does not become higher than necessary with respect to the pressure P2 in the intermediate region C, and the pressure ratio P1 / P2 is kept the same as before the pressure fluctuation, that is, It is held constant (P1 / P2 = ξ).

  As described above, even when the pressure P1 in the sealed fluid region A increases and / or the pressure P2 in the intermediate region C decreases, the differential pressure between the pressures P1 and P2 is set to the preset differential pressure (P1a-P2a). ) More than necessary, an excessive load does not act on the first mechanical seal 1a, and the sealing function of the first mechanical seal 1a is exhibited well.

  Also, when the pressure P1 in the sealed fluid region A decreases due to a change in the operating condition of the rotating device, or when the pressure P2 in the intermediate region C increases due to leakage of the sealed fluid from the first mechanical seal 1 to the intermediate region C, etc. As shown in FIG. 6C, the piston 42 moves in the direction of increasing the volume of the low pressure fluid space 43b (for example, moves upward from the reference position), and the volume of the low pressure fluid space 43b is increased. A pressure decrease corresponding to the increase amount is propagated from the low-pressure fluid pipe 42 to the intermediate region C, and the pressure P2 in the intermediate region C decreases. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P1 of the high-pressure fluid space 43a and the pressure P2 of the low-pressure fluid space 43b. P1 / P2 is equivalent to the piston pressure receiving area ratio ξ (the set pressure ratio P1a / P2a) and is constant, as in the case described above.

  Accordingly, even when the pressure P1 in the sealed fluid region A decreases and / or the pressure P2 in the intermediate region C increases, the differential pressure between the pressures P1 and P2 becomes a preset differential pressure (P1a-P2a). In comparison, the reverse pressure phenomenon (P1 <P2) in which the relationship between the pressures P1 and P2 is reduced more than necessary does not occur, and the sealing function by the first mechanical seal 1a is satisfactorily exhibited.

  Thus, in the first mechanical seal device, even when the pressure P1 in the sealed fluid region A and / or the pressure P2 in the intermediate region C changes, the pressure ratio P1 / P2 is always constant. As a result, the pressure function P1 / P2 is increased or decreased abnormally or the back pressure phenomenon (P1 <P2) is caused. To be prevented.

  By the way, in the pressure equalizer 4a, as described above, the piston 42 moves in the cylinder 41 in order to keep the pressure ratio P1 / P2 between the pressure P1 in the sealed fluid region A and the pressure P2 in the intermediate region C constant. (Moving up and down) By attaching a detector for detecting the amount or position of movement to the pressure equalizer 4a, it is possible to detect abnormalities in rotating equipment or mechanical seals, and to determine the operating status of rotating equipment or mechanical seals. It becomes possible to monitor. Various detection devices for detecting the movement amount or the movement position of the piston 42 can be considered. In this example, as shown in FIG. 6, the pressure equalizing device 4a moves the piston 42 up and down as shown in FIG. A limit switch 45a, 45b that is turned ON / OFF by a piston rod 42a protruding upward from the cylinder 41 and a measure 46 for visually detecting the movement amount of the piston 42 at the upper end position of the piston rod 42a are attached. It is. That is, the upper end of the piston rod 42a (or the piston rod 42a is provided when the piston 42 is positioned on the upper surface of the cylinder 41 at the upper limit position (a chain line position in FIG. 6C) where the piston 42 is raised by a predetermined amount from the reference position. The piston rod when the upper limit switch 45a and the piston 42, which are turned on (or turned off) by the actuator, are positioned at the lower limit position (chain line position in FIG. 6A) that is lowered by a predetermined amount from the reference position. A lower limit switch 45b that is turned off (or turned on) by the upper end of 42a (or an actuator provided on the piston rod 42a) is supported to detect that the piston 42 has moved to the upper limit position or the lower limit position. It has become. Accordingly, it is possible to detect that the pressure P1 of the sealed fluid K is abnormally decreased or the pressure P2 of the intermediate region C is abnormally increased by the ON operation (or OFF operation) of the upper limit switch 45a. When the limit switch 45b is turned OFF (or ON), it can be detected that the pressure P1 of the sealed fluid K has abnormally increased or the pressure P2 of the intermediate region C has abnormally decreased. Performing some countermeasures (for example, stopping rotating equipment) by the above operation of 45b artificially (for example, issuing an appropriate alarm by operating the limit switches 45a and 45b, so that the operator can manually perform the countermeasures) Or can be done automatically, causing fatal problems with rotating equipment and mechanical seals. It can be avoided.

  Further, as shown in FIG. 6, a measure 46 for visually detecting the amount of movement of the piston 42 by an upper end of the piston rod 42a (or a pointer provided on the piston rod 42a) is erected on the upper wall of the cylinder 41 so as to be sealed. The pressure fluctuation in the fluid area A or the pressure fluctuation in the intermediate area C can be visually monitored, so that the operator can accurately grasp the operating status of the rotating device and the mechanical seal. Such monitoring can also be performed by electrically detecting the amount of movement of the piston rod 42a and displaying it on the monitor screen.

  By the way, in the first mechanical seal device, the intermediate region C is merely filled and sealed with the sealing liquid L having a predetermined pressure P2a. Therefore, a simple means such as a hand pump can be used as the filling and sealing means for the sealing liquid L. It is sufficient to use a pump, and a pressure unit having a high-performance pump or the like as in the case of circulating and supplying a sealing liquid having a predetermined pressure as described at the beginning does not need this. Accordingly, the initial cost and running cost of the mechanical seal device can be greatly reduced in combination with the pressure equalizing device 4a having a simple piston / cylinder structure as compared with the case where a pressure unit is provided. The device structure can also be greatly simplified and downsized. Moreover, since the sealing liquid L is filled and sealed only at the start of operation, the pressure equalizing device 4a is used not only when a hand pump is used as a filling and sealing means but also when a pump requiring a power source is used. In combination with the fact that the power source does not require a power source, there is no problem that the pressure in the intermediate region is not properly maintained due to the stoppage of the pump due to a power failure or the like and the seal is damaged due to overload.

  Thus, in this example, as shown in FIG. 2, the hand pump 71c is used as the filling / sealing means for the sealing liquid L. At the start of operation, the hand pump 71c causes a predetermined pressure from the low pressure fluid pipe 71b. The sealing liquid L of P2a is filled and sealed in the intermediate region C (and the low-pressure fluid space 43b of the pressure equalizer 4a). If necessary, the high-pressure fluid pipe 71a is provided with a pressure gauge 71d, and the low-pressure fluid pipe 71b is provided with a pressure transmitter 71e, a safety valve 71f, a pressure gauge 71g, an accumulator 71h, and the like.

  Further, in the first mechanical seal device, as shown in FIGS. 1 and 2, the seal case 5 is opened to the first supply / drainage ports 51c and 51d and the second flushing region C1 which are opened to the first flushing region A1. As shown in FIG. 2, circulation paths 51i, 51j having coolers 51g, 51h are provided between the first and second liquid supply ports 51c, 51d and 51e, 51f, respectively. And the seal portion of the first mechanical seal 1a (the relative rotational sliding contact portion of both seal rings 11 and 12) and the seal portion of the second mechanical seal 2a (the relative rotational sliding contact portion of both rings 22 and 23). It is devised to flush. In general, fresh water or the like is used as the flushing liquid. In this example, a part of the sealed fluid K that fills the first flushing region C1 is used for the first mechanical seal 1a, and the second mechanical seal 2a. In contrast, a part of the sealing liquid L filling the second flushing region C1 is used. The second liquid supply port 51e is opened between the stationary ring 21 and the idle ring 23, and the flushing liquid L supplied between the rings 21 and 23 from the second liquid supply port 51e is: It passes through the communication hole 23 of the idle ring 23 and reaches the seal portion of the second mechanical seal 2a. Further, the flushed liquids K and L are separated from the flushing areas A1 and C1 by the pumping action of the circulation rings 16 and 27 (the sealed fluid area portion excluding the first flushing area A1 or the second flushing area C1). The liquid is discharged from the flushing areas A1 and C1 to the drainage ports 51d and 51f without flowing into the intermediate area portion. That is, the flushing liquids K and L supplied from the liquid supply ports 51c and 51e to the flushing areas A1 and C1 are received by the circulation rings 16 and 27 and guided to the cylindrical portions 16a and 27a by the centrifugal force due to the rotation. Then, the liquid is discharged from the circulation holes 16b and 27b of the cylindrical portions 16a and 27a to the drainage ports 51d and 51f that open oppositely.

  3, 4, and 6 show a second embodiment of the high-pressure mechanical seal device according to the present invention, and FIG. 3 is a longitudinal side view of the main part of the mechanical seal device. FIG. 6 is a system diagram showing the overall configuration of the mechanical seal device, and FIG. 6 is a longitudinal side view showing an example of a pressure equalizer used for the mechanical seal.

  The mechanical seal device for high-pressure fluid (hereinafter referred to as “second mechanical seal device”) shown in FIG. 3 and FIG. 4 is a saddle type that handles liquid high-pressure fluid (for example, high-pressure water) as in the first mechanical seal device. Used as a shaft sealing means of a rotating device (for example, a vertical axis high pressure pump), a first mechanical seal 1b on the sealed fluid region side, a third mechanical seal 3b on the atmospheric region side, and both mechanical seals 1b, The second mechanical seal 2b located between 3b is arranged between the seal case 5 and the rotary shaft 6 having the same structure as that in the first mechanical seal device, and is arranged in series in the axial direction. When the first intermediate sealing region L formed between the second mechanical seals 1b and 2b is filled and sealed with the first sealing liquid L1 having a pressure higher than that of the sealed fluid (the high pressure liquid in the sealed fluid region A). The second intermediate region E formed between the second and third mechanical seals 2b and 3b is filled and sealed with the second seal liquid L2 having a pressure lower than that of the first intermediate region D, and the sealed fluid region which is the in-machine region A triple seal configured to seal A and the atmospheric region B, which is an out-of-machine region, via the first and second intermediate regions D and E. The seal liquids L1 and L2 are the first mechanical components. As with the sealing device, fresh water is used.

  As shown in FIG. 3, the first mechanical seal 1 b is moved in the axial direction to the stationary seal ring 31 fixed to the seal case 5 and the rotary shaft 6 penetrating the seal case 5 by being arranged on the atmosphere region side (upper side). A rotary seal ring 32 held in a possible manner and a spring 33 for pressing and urging the rotary seal ring 32 to the stationary seal ring 31 are provided, and the relative rotational sliding contact of the sealing end surfaces as opposed end surfaces of the both seal rings 31 and 32 is provided. By the action, an end face contact type mechanical seal configured to shield and seal the sealed fluid region A including the inner peripheral region of the relative rotational sliding contact portion and the first intermediate region D including the outer peripheral region thereof. is there. The rotary seal ring 32 is fitted and held on the sleeve 6b of the rotary shaft 6 via an O-ring 34 so as to be movable in the axial direction. A spring retainer 35 is fixed to the sleeve 6 b of the rotary shaft 6 on the atmosphere region side of the rotary seal ring 32, and the rotary seal ring 32 is stationary between the spring retainer 35 and the rotary seal ring 32. A spring 33 that biases the sealing ring 31 so as to be pressed and a drive pin 37 that prevents relative rotation of the rotary sealing ring 32 with respect to the rotary shaft 6 are interposed. In addition, the 1st mechanical seal 1b and the 2nd mechanical seal 2b mentioned later have comprised the double seal structure which reverses the sealing ring arrangement | positioning in an up-down direction.

  The second and third mechanical seals 2b and 3b are tandem seals having the same structure as the first and second mechanical seals 1a and 1b of the first mechanical seal device. Accordingly, the constituent members of the second and third mechanical seals 2b and 3b that are the same as the constituent members of the first and second mechanical seals 1a and 2a are shown in FIGS. 3 and 4 in FIGS. The details are omitted by attaching the same reference numerals.

  As shown in FIG. 3, the second mechanical seal 2b has the same structure as that of the first mechanical seal 1a, and the relative rotational sliding contact action of the sealing end surfaces which are the opposite end surfaces of the two sealing rings 11 and 12 It is an end face contact type mechanical seal configured to shield and seal the first intermediate region D including the outer peripheral side region of the rotating sliding contact portion and the second intermediate region E including the inner peripheral side region. A circulation ring 38 is formed at the base end of the spring retainer 15 of the second mechanical seal 1b. The circulation ring 38 has the same configuration as the circulation ring 27 of the second mechanical seal 2b, and its outer peripheral portion is formed as a cylindrical portion 38a that protrudes upward and is close to the inner peripheral surface of the seal case 5. The cylindrical portion 38a is formed with a plurality of circulation holes 38b penetrating therethrough in the radial direction. The first intermediate region D includes an arrangement region (hereinafter referred to as “first flushing region”) D1 of the second mechanical seal 2b which is an outer peripheral side region of the relative rotational sliding contact portions of the sealing rings 11 and 12 by the circulation ring 38. It is partitioned into other areas.

  As shown in FIG. 3, the third mechanical seal 3b has the same structure as that of the second mechanical seal 2a. The relative rotation of the third mechanical seal 3b is achieved by the relative rotational sliding contact action of the sealed end surfaces of the two rings 22 and 23. This is an end face contact type mechanical seal configured to shield and seal the second intermediate region E including the outer peripheral side region of the sliding contact portion and the atmospheric region B including the inner peripheral side region thereof. The second intermediate region E is provided with a third mechanical seal 3b (hereinafter referred to as “second region”) which is an outer peripheral side region of the relative rotational sliding contact portion of both rings 22 and 23 by a circulation ring 27 formed integrally with the spring retainer 26. It is divided into E1 and other areas.

  The seal case 5 has a cylindrical shape having a circular inner peripheral surface. As shown in FIGS. 3 and 4, the first low-pressure fluid port 52 a that opens to the sealed fluid region A and the high-pressure fluid that opens to the first intermediate region D are used. A second low-pressure fluid port 52c that opens to the port 52b and the second intermediate region E is formed. The high pressure fluid port 52b is an appropriate place in the first intermediate region D excluding the first flushing region D1 and is opened in the vicinity of the circulation ring 38, and the second low pressure fluid port 52c is an appropriate location in the second flushing region E1. An opening is formed between the idle ring 23 and the circulation ring 27.

  Thus, the high-pressure fluid port 52b, the first low-pressure fluid port 52a, and the second low-pressure fluid port 52c are connected in communication via the first and second pressure equalizers 4b and 4c, as shown in FIGS. The pressure ratio P4 / P3 between the pressure in the sealed fluid region A (pressure of the sealed fluid Kb) P3 and the pressure in the first intermediate region D (pressure of the first sealing liquid L1) P4 and the first intermediate region D The pressure ratio P4 / P5 between the second pressure P3 and the pressure in the second intermediate region E (the pressure of the second cylinder fluid L2) P5 is kept constant.

  As shown in FIG. 6, each of the pressure equalizers 4b and 4c is formed by loading a piston 42 in a cylinder 41, and a piston pressure receiving area ratio (low pressure fluid space 43b with respect to piston pressure receiving area S1 in high pressure fluid space 43a). Except for the ratio (S2 / S1) of the piston pressure receiving area S2 in FIG.

  As shown in FIG. 4, the high-pressure fluid port 52b of the seal case 5 is connected to the high-pressure fluid port 41a of the first pressure equalizing device 4b by the first high-pressure fluid pipe 72a and is secondly connected by the second high-pressure fluid pipe 73a. The high pressure fluid port 41a of the pressure equalizer 4c is connected in communication. 4, the first low-pressure fluid port 52a of the seal case 5 is connected to the low-pressure fluid port 41b of the first pressure equalizing device 4b through the first low-pressure fluid pipe 72b. The low pressure fluid port 52c is connected in communication with the low pressure fluid port 41b of the second pressure equalizing device 4c by a second low pressure fluid pipe 73b.

  In the first pressure equalizing device 4b, the piston pressure receiving area ratio ξ1 is the pressure of the sealed fluid Kb set at the design stage or the operation start stage of the second mechanical seal device (hereinafter referred to as “sealed fluid set pressure P3a”). And a pressure ratio P4a / P3a equivalent to the pressure in the first intermediate region D (hereinafter referred to as “first seal fluid set pressure P4a”) set higher by a predetermined pressure (slight pressure) than this (ξ1 = S2 / S1 = P4a / P3a) In the operation start stage (when P3 = P3a and P4 = P4a), as shown in FIG. It is set to be positioned at a position (hereinafter referred to as “reference position”).

  In the second pressure equalizer 4c, the pressure in the second intermediate region E in which the piston pressure receiving area ratio ξ2 is set to be a predetermined pressure lower than the first seal fluid set pressure P4a at the design stage or operation start stage of the second mechanical seal device. It is set to be equivalent to the pressure ratio P4a / P5a (hereinafter referred to as “second seal fluid set pressure P5a”) and the first seal fluid set pressure P4a (ξ2 = S2 / S1 = P4a / P5a). In the operation start stage (when P4 = P4a and P5 = P5a), the piston 42 is positioned at the intermediate position in the vertical direction of the cylinder 41 (hereinafter referred to as “reference position”) as shown in FIG. Is set to

  The second high-pressure fluid pipe 73a (or the first high-pressure fluid pipe 72a) is a simple pump (in this example, for filling the first intermediate region D with the first seal liquid L1 having a predetermined pressure P4a at the start of operation). Hand pump) 73c is disposed, and a pressure gauge 73d and the like are further provided as necessary. The second low-pressure fluid pipe 73b is provided with a simple pump (in this example, a hand pump) 73e for filling the second intermediate region E with the second seal liquid L2 having a predetermined pressure P5a at the start of operation. Further, a pressure transmitter 73f, a safety valve 73g, a pressure gauge 73h, an accumulator 73i, and the like are provided as necessary.

  Even in the second mechanical seal device, the second and third mechanical seals 2b and 3b are devised so as to be flushed, similarly to the first mechanical seal device. That is, as shown in FIGS. 3 and 4, the seal case 5 has first supply / drain liquid ports 52d and 52e opened in the first flushing area D1 and second supply / drain liquid ports 52f and 52g opened in the second flushing area E1. As shown in FIG. 4, the first and second liquid supply and discharge ports 52d, 52e and 52f, 52g are connected by circulation paths 52j, 52k having coolers 52h, 52i, respectively, and the second mechanical seal 2b. The seal portion (the relative rotational sliding contact portion between both seal rings 11 and 12) and the seal portion (the relative rotational sliding contact portion between both rings 22 and 23) of the third mechanical seal 3b are devised. In general, fresh water or the like is used as the flushing liquid. In this example, a part of the first seal liquid L1 filling the first flushing region D1 is used for the second mechanical seal 2b, and the third mechanical seal is used. For 3b, a part of the second sealing liquid L2 filling the second flushing region E1 is used. The flushed liquids L1 and L2 are discharged from the flushing areas D1 and E1 as they are to the drainage ports 52e and 52g by the pumping action by the circulation rings 27 and 38, as in the first mechanical seal device.

  In the second mechanical seal device configured as described above, when the pressure P3 in the sealed fluid region A is reduced due to a change in the operating state of the rotating equipment (for example, lower than the sealed fluid set pressure P3a). 6B, the piston 42 moves in the direction in which the volume of the high-pressure fluid space 43a is increased in the first pressure equalizing device 4b as shown in FIG. 6B (for example, the reference position (shown in FIG. 6A)). The pressure decrease corresponding to the volume increase amount of the high-pressure fluid space 43a is propagated from the high-pressure fluid pipe 72a to the first intermediate region D, and the pressure P4 in the first intermediate region D is increased. It will descend. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P4 in the high-pressure fluid space 43a and the pressure P3 in the low-pressure fluid space 43b. P4 / P3 is equivalent to the piston pressure receiving area ratio ξ1 (= P4a / P3a) and does not change. That is, the pressure P4 in the first intermediate region D does not become higher than necessary as compared with the pressure P3 in the sealed fluid region A, and the pressure ratio P4 / P3 is kept the same as before the pressure fluctuation. Will be. Therefore, even when the pressure P3 in the sealed fluid region A decreases, there is a problem that the differential pressure between the pressure P3 and the pressure P4 in the first intermediate region D becomes abnormally high (for example, in the first mechanical seal 1a An excessive load is applied), and the sealing function by the first mechanical seal 1b is satisfactorily exhibited.

  Further, when the pressure P3 in the sealed fluid region A increases due to a change in the operating condition of the rotating equipment, or due to leakage of the first seal liquid L1 from the second mechanical seal 2b to the second intermediate region E, the first intermediate region D As shown in FIG. 6C, the piston 42 moves in the direction of decreasing the volume of the high pressure fluid space 43a in the first pressure equalizing device 4b (for example, upward from the reference position), as shown in FIG. The pressure increase corresponding to the volume reduction amount of the high pressure fluid space 43a is propagated from the high pressure fluid pipe 72a to the first intermediate region D, and the pressure P4 in the first intermediate region D increases. Become. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P4 in the high-pressure fluid space 43a and the pressure P3 in the low-pressure fluid space 43b. As in the case described above, P4 / P3 is equivalent to the piston pressure receiving area ratio ξ1 (= P4a / P3a) and is kept constant.

  Therefore, even when the pressure P3 in the sealed fluid region A increases and / or the pressure P4 in the first intermediate region D decreases, both the pressures P3 and P4 do not reverse, that is, the reverse pressure (P4 <P3) does not act on the first mechanical seal 1b, and the sealing function by the first mechanical seal 1b is satisfactorily exhibited.

  Further, when the pressure P5 in the second intermediate region E decreases due to leakage of the second seal liquid L2 from the third mechanical seal 3b to the atmospheric region B, or as the pressure in the sealed fluid region A increases, the first pressure equalizer When the pressure P4 in the second intermediate region D rises due to 4b, as shown in FIG. 6 (B), the piston 42 moves in the direction in which the volume of the low-pressure fluid space 43b is reduced in the second pressure equalizer 4c ( For example, the pressure increases according to the volume reduction amount of the low pressure fluid space 43b from the reference position (position shown in FIG. 6A) to the second intermediate region E from the low pressure fluid pipe 73b. Propagated and the pressure P5 in the second intermediate region E increases. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P4 in the high-pressure fluid space 43a and the pressure P5 in the low-pressure fluid space 43b. P4 / P5 is equivalent to the piston pressure receiving area ratio ξ2 (= P4a / P5a) and does not change. That is, the pressure P4 in the first intermediate region D does not become higher than necessary as compared with the pressure P5 in the second intermediate region E, and the pressure ratio P4 / P5 is kept the same as before the pressure fluctuation. Will be. Accordingly, even in the above-described case, there is a problem that the differential pressure between the pressure P4 in the first intermediate region D and the pressure P5 in the second intermediate region E becomes abnormally large (for example, an excessive pressure is applied to the second mechanical seal 2b). No load is applied), and the sealing function by the second mechanical seal 2b is satisfactorily exhibited.

  Further, when the pressure P4 in the first intermediate region D is reduced by the first pressure equalizing device 4b as the pressure in the sealed fluid region A decreases, the first seal liquid L1 leaks from the second mechanical seal 2b to the second intermediate region E. Thus, when the pressure P5 in the third intermediate region E increases (or when the pressure P4 in the first intermediate region D decreases), as shown in FIG. 6C, the piston 42 in the second pressure equalizer 4c. Moves in a direction to increase the volume of the low-pressure fluid space 43b (for example, moves upward from the reference position), and the pressure decrease corresponding to the volume increase amount of the low-pressure fluid space 43b is reduced to the low-pressure and high-pressure fluid pipe 73b. To the second intermediate region E, the pressure P5 in the second intermediate region E decreases. The piston 42 stops at a position where the pressing force due to the fluid pressure acting on both sides of the piston 42 is balanced. At this time, the pressure ratio between the pressure P4 in the high-pressure fluid space 43a and the pressure P5 in the low-pressure fluid space 43b. As in the case described above, P4 / P5 is equivalent to the piston pressure receiving area ratio ξ2 (= P4a / P5a) and is kept constant.

  Therefore, even when the pressure P4 in the first intermediate region D decreases and / or the pressure P5 in the second intermediate region D increases in this way, both the pressures P4 and P5 do not reverse, that is, reverse The pressure (P4 <P5) does not act on the second mechanical seal 2b, and the sealing function by the second mechanical seal 2b is exhibited well.

  Thus, in the second mechanical seal device, the pressure relationship (pressure ratio) among the pressure P3 in the sealed fluid region A, the pressure P4 in the first intermediate region D, and the pressure P5 in the second intermediate region E is as follows. Is properly held by the first and second pressure equalizers 4b and 4c, and a good sealing function is exhibited.

  In addition, the piston moving position or moving amount detection device (limit switches 45a, 45b and measure 46) provided in each of the pressure equalizers 4b, 4c can be used to accurately check the operation status of the second mechanical seal device and the rotating equipment equipped with the second mechanical seal device. It is the same as that of the above-mentioned 1st mechanical seal apparatus that it can grasp | ascertain.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately improved and changed without departing from the basic principle of the present invention.

  For example, the mechanical seal device having a mechanical seal number n of 2 is not limited to a tandem seal such as the first mechanical seal device, but the first mechanical seal 1a and the second mechanical seal 2a are reversed in their sealing rings. It is also possible to use a double seal arranged in the direction. In this case, when the first intermediate region C is filled and sealed with a sealing liquid having a pressure higher than that of the sealed fluid region A, the sealed fluid region A and the first intermediate region D in the second mechanical seal device are divided into both regions A and C. The configuration is the same as that in the case where the first pressure equalizing device 4b is connected in communication.

  Further, as a mechanical seal device in which the number of mechanical seals n is 3, a double seal structure (a seal structure formed by the first mechanical seal 1b and the second mechanical seal 2b) and a tandem seal structure ( Instead of the combination of the second mechanical seal 2b and the third mechanical seal 3b), as shown in FIG. 5, all the mechanical seals may have a tandem seal structure.

  That is, in the high-pressure fluid mechanical seal device shown in FIG. 5 (hereinafter referred to as “third mechanical seal device”), the first, second, and third mechanical seals 1c, 2c, 3c are provided in the seal case 5, respectively. An end face contact type mechanical seal configured to exhibit a sealing function by a relative rotational sliding contact action between the stationary seal ring (or idle ring) 101 and the rotary seal ring (or rotary ring) 102 provided on the rotary shaft 6. Each mechanical seal and a mechanical seal adjacent thereto form a tandem seal structure, and the first intermediate region F between the first and second mechanical seals 1c, 2c has a lower pressure than the sealed fluid region A. 1 seal liquid is filled and sealed, and the second intermediate liquid G having a lower pressure than the first intermediate area F is filled and sealed in the second intermediate area G between the second and third mechanical seals 2c and 3c. To, and is configured to seal through the ambient air into the region B the sealed fluid region A middle region F, G. And in this 3rd mechanical-seal apparatus, as shown in FIG. 1 between 1st intermediate | middle area | region F and the to-be-sealed fluid area | region A and 2nd intermediate | middle area | region G adjacent to this, The pressure equalizers 4a, 4b, 4c used in the mechanical seal device are connected in communication via pressure equalizers 4d, 4e having the same structure. That is, as shown in FIG. 5, the high-pressure fluid port 53a of the seal case 5 that opens to the sealed fluid region A and the high-pressure fluid port 41a of the first pressure equalizing device 4d are connected by the first high-pressure fluid pipe 74a. The first low-pressure fluid port 53b of the seal case 5 opening in the intermediate region F and the low-pressure fluid port 41b of the first pressure equalizing device 4d are connected by a first low-pressure fluid pipe 74b, and the first low-pressure fluid port 53b and the second pressure-equalization port are connected. The high-pressure fluid port 41a of the pressure device 4e is connected by the second high-pressure fluid pipe 75a, and the second low-pressure fluid port 53c of the seal case 5 that opens to the second intermediate region G and the low-pressure fluid port 41b of the second pressure equalizer 4e Are connected by a second low-pressure fluid pipe 75b. The piston pressure receiving area ratio in the first pressure equalizing device 4d depends on the pressure relationship between the sealed fluid region A and the first intermediate region F, and the piston pressure receiving area ratio in the second pressure equalizing device 4e is the pressure in the intermediate regions F and G. Each is set according to the relationship. Thus, in the third mechanical seal device, by the same action as in the case where the pressure relationship between the sealed fluid region A and the intermediate region C is properly held by the pressure equalizer 4a in the first mechanical seal device, The pressure relationship (pressure ratio) between the first intermediate region F, the sealed fluid region A, and the second intermediate region G is properly maintained by the pressure equalizers 4d and 4e. The second high-pressure fluid pipe 75a (or the first low-pressure fluid pipe 74a) is a simple pump (in this example, for filling the first intermediate region F with the first seal liquid having a predetermined pressure at the start of operation). (Hand pump) 75c, and a pressure gauge 75d and the like are further provided as necessary. The second low-pressure fluid pipe 75b is provided with a simple pump (in this example, a hand pump) 75e for filling the second intermediate region G with a second seal liquid having a predetermined pressure at the start of operation. A pressure transmitter 75f, a safety valve 75g, a pressure gauge 75h, an accumulator 75i, and the like are provided as necessary. Further, even in the third mechanical seal device, it is possible to provide flushing means similar to the first mechanical seal device or the second mechanical seal device.

  The present invention can also be applied to a high-pressure fluid mechanical seal device having a mechanical seal number n of 4 or more. In this case, the piston pressure receiving area ratio (the piston pressure receiving area of the low pressure fluid space divided by the piston area of the high pressure fluid space) is set between each intermediate region and the adjacent intermediate region and the sealed fluid region. Using n-1 pressure equalizers configured to match a preset pressure ratio between the high pressure fluid region and the low pressure fluid region (high pressure fluid divided by low pressure fluid pressure); The high pressure fluid region is connected to the high pressure fluid space of the pressure equalizer and the low pressure fluid region is connected to the low pressure fluid space of the pressure equalizer.

  Further, the mechanical seal device of the present invention is used as a shaft sealing means of a vertical rotating device that handles high-pressure liquid as described above, as well as a horizontal rotating device that handles high-pressure liquid and a vertical or horizontal type that handles high-pressure gas. It can also be suitably used as a shaft sealing means for a rotating device or the like.

1a First mechanical seal (end face contact type mechanical seal)
1b First mechanical seal (end face contact type mechanical seal)
1c First mechanical seal (end face contact type mechanical seal)
2a Second mechanical seal (end face contact type mechanical seal)
2b Second mechanical seal (end face contact type mechanical seal)
2c Second mechanical seal (end surface contact type mechanical seal)
3b Third mechanical seal (end face contact type mechanical seal)
3c 3rd mechanical seal (end face contact type mechanical seal)
4a Pressure equalizer 4b 1st pressure equalizer 4c 2nd pressure equalizer 4d 1st pressure equalizer 4e 2nd pressure equalizer 5 Seal case 6 Rotating shaft 11 Stationary seal ring 12 Rotation seal ring 13 Spring 21 Stationary ring 22 Rotation ring 23 Free ring 24 Spring 41 Cylinder 41a High Pressure Fluid Port 41b Low Pressure Fluid Port 42 Piston 42a Piston Rod 43a High Pressure Fluid Space 43b Low Pressure Fluid Space 45a Limit Switch (Detection Device)
45b Limit switch (detection device)
46 Major (detection device)
71a High-pressure fluid piping 71b Low-pressure fluid piping 72a First high-pressure fluid piping 72b First low-pressure fluid piping 73a Second high-pressure fluid piping 73b Second low-pressure fluid piping 74a First high-pressure fluid piping 74b First low-pressure fluid Pipe 75a Second high-pressure fluid pipe 75b Second low-pressure fluid pipe 101 Stationary seal ring 102 Rotating seal ring A Sealed fluid area B Atmosphere area C Intermediate area D First intermediate area E Second intermediate area F First intermediate area G Second intermediate region K Sealed fluid L Seal liquid L1 First seal liquid L2 Second seal liquid

Claims (5)

A mechanical system for high-pressure fluid in which a plurality of end-face contact type mechanical seals are arranged in series in the axial direction, and the sealed fluid region and the atmospheric region are shielded and sealed through an intermediate region formed between the mechanical seals. In the sealing device,
Each intermediate region is filled and sealed with a sealing liquid having a pressure different from that of the intermediate region adjacent to the intermediate region or the sealed fluid region,
The number of pressure equalizers equal to the number of intermediate regions, each of which is divided into a space for low pressure fluid and a space for high pressure fluid whose piston pressure receiving area is smaller than the space for low pressure fluid by a piston in which a sealed space in the cylinder is removably loaded. And each intermediate region is connected to one of the low-pressure fluid space and the high-pressure fluid space of each pressure equalizer, and the low-pressure fluid space of the pressure equalizer is connected to the intermediate region adjacent to the intermediate region or the sealed fluid region. And a high-pressure fluid connected to the other of the high-pressure fluid space so that the pressure ratio between each intermediate region and the adjacent intermediate region or sealed fluid region is kept constant. Mechanical seal device.   A tandem seal in which an intermediate region formed between a first mechanical seal on the sealed fluid region side and a second mechanical seal on the atmospheric region side is filled and sealed with a sealing liquid having a pressure lower than that of the sealed fluid region. The area is connected to the low pressure fluid space of the pressure equalizer and the sealed fluid area is connected to the high pressure fluid space of the pressure equalizer so that the pressure ratio between the sealed fluid area and the intermediate area is kept constant. The mechanical seal device according to claim 1, wherein the mechanical seal device is configured as described above.   The first mechanical seal on the sealed fluid region side, the third mechanical seal on the atmospheric region side, and the second mechanical seal located between the two mechanical seals, the first and second mechanical seals form a double seal structure and the second And the third mechanical seal is arranged so as to form a tandem seal structure, and the first intermediate liquid formed between the first and second mechanical seals is filled and sealed with a first seal liquid having a pressure higher than that of the sealed fluid. The second intermediate region formed between the second and third mechanical seals is filled and sealed with a second sealing liquid having a pressure lower than that of the first intermediate region, and the first intermediate region communicates with the high pressure fluid space of the first pressure equalizing device. And connected to the high pressure fluid space of the second pressure equalizer, the sealed fluid region is connected to the low pressure fluid space of the first pressure equalizer, and the second intermediate region is connected to the low pressure of the second pressure equalizer. The pressure ratio between the sealed fluid region and the first intermediate region and the pressure ratio between the two intermediate regions are respectively maintained constant by being connected to the body space. A mechanical seal device for high pressure fluid to be described.   The first mechanical seal on the sealed fluid region side, the third mechanical seal on the atmospheric region side, and the second mechanical seal located between the two mechanical seals are arranged to form a tandem seal structure, and the first and second The first intermediate region formed between the second and third mechanical seals is filled and sealed in the first intermediate region formed between the two mechanical seals and filled with the first seal liquid having a pressure lower than the fluid to be sealed. A lower pressure second sealing liquid is filled and sealed, and the first intermediate region is connected in communication with the low pressure fluid space of the first pressure equalizing unit and is connected in communication with the high pressure fluid space of the second pressure equalizing unit. Are connected in communication with the high pressure fluid space of the first pressure equalizing unit and the second intermediate region is connected in communication with the low pressure fluid space of the second pressure equalizing unit, so that the pressure ratio between the sealed fluid region and the first intermediate region and both Middle area pressure There characterized by being configured to be retained respectively constant, the mechanical seal device for a high-pressure fluid according to claim 1.   The mechanical seal device for high-pressure fluid according to any one of claims 1 to 4, wherein the pressure equalizer is provided with a detection device capable of detecting a movement position or movement amount of the piston.

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