KR101184597B1 - Double mechanical seal - Google Patents

Abstract

The present invention relates to a double mechanical seal, and a pair of stator parts fixed to the case of the impeller side and the motor side, respectively comprising a sheet having a perturbation surface and a sealing member for sealing the case; and a motor A collar fixed to the shaft, a plurality of driving pins protruding in the longitudinal direction of the motor shaft from both ends of the collar, a plurality of springs provided in the through-holes in the longitudinal direction of the motor shaft provided in the collar, and installed at both ends of the spring It consists of a pair of retainers, and a rotor portion which is fastened to one side of the retainer and composed of a pair of seal faces provided with a perturbation surface, the outer periphery of the seal face is formed in the distal end of the drive pin A corresponding groove is provided, and the end of the driving pin rotated in conjunction with the motor shaft and the groove of the seal face are fastened to the seal face. It characterized in that the axis rotating force is transmitted.
According to the present invention, since the rotational force of the motor shaft can be transmitted to the seal face through the drive pin by using the distal end of the drive pin and the groove on the seal face, there is no fear of the bellows tearing under high temperature and high pressure conditions or even in a large size. There is an advantage that the transmission of more stable rotational force is possible, and the collar can be fixed to the proper position on the motor shaft by adjusting the free length of the spring, so that one person can easily install the double mechanical seal. .

Description

Double mechanical seal {DOUBLE MECHANICAL SEAL}

The present invention relates to a double mechanical seal, and more particularly, to a double mechanical seal capable of transmitting the rotational force of the motor shaft to the rotor more stably, and easily fixing the collar even under no load.

A mechanical seal is a surface contact sealing device for sealing a motor shaft that is fastened to a pump or a turbine of a generator, and specifically, a stator and a rotor forming two perturbation surfaces perpendicular to the motor shaft are face contacted. The sealing is achieved by an oil film generated while the rotor rotates together with the motor shaft so that the sealing with the stator can be continuously maintained by the tension of the spring or the pressure of the fluid. Such a mechanical seal is an absolutely necessary device for preventing the leakage of fluid to the motor, and the perturbation surface is lubricated by a fluid film (1 to 3 µm) formed by itself.

For example, in the case of a mechanical seal used in a slurry pump, when the rotating shaft to which the propeller is connected is rotated, the rotor connected to the rotating shaft is also rotated, so that fluid is minutely introduced into the contact portion between the rotor and the stator and the lubricating film Is formed. On the other hand, as the decelerator accelerates and decelerates, the rotor vibrates back and forth. In this case, the rotor is elastically supported by the spring to maintain the sealed state.

As such, the mechanical seal is characterized by preventing visible leakage, no abrasion of the shaft, but instead all abrasion only at the seal face. In addition, there is an advantage that the automatic compensation is made as much as the portion worn by the tension of the spring is mounted can be continuously made.

Fig. 1 (a) is a sectional view of a conventional single mechanical seal, and Fig. 1 (b) shows a sectional view of a conventional double mechanical seal.

As shown in Figure 1 (a), the conventional mechanical seal is a seal face (①), rubber bellows (②), rotary housing (③), spring (④), seat (⑤), cup gasket (⑥) )

Specifically, the seal face (①) is assembled to the rubber bellows (②), and fixed by pressing the seal so that the seal face (①) is not separated from the rubber bellows (②) using a rotary housing (③). The spring (④) is inserted while being compressed between the two rotary housing (③), so that a constant surface pressure can be formed and maintained between the seal face (①) and the seat (⑤) when the seal is assembled. This prevents leakage.

However, such a conventional mechanical seal has some problems. In other words, when the rotational force of the motor shaft is transmitted to the seal face, it is transmitted through the rubber bellows.Therefore, there is a risk of tearing the rubber bellows in the case of high temperature, high pressure, or large size. It does not work consistently, which increases the risk of leakage and shortens the life of the seal. In addition, due to the limitations of the spring wire diameter, when the shaft is a large size, there is a problem in that it is impossible to produce a spring that can give sufficient surface pressure.

Meanwhile, the double mechanical seal illustrated in FIG. 1 (b) is a double seal structure having a pair of seal faces 110A and 110B, and may not provide an appropriate lubricating fluid to the perturbation surface, or may be different from each other. It is mainly used when both kinds of fluids need to be prevented from leaking at the same time, or when it is necessary to increase the stability and the life for the abrasive fluid. However, such a double mechanical seal had the same problem as the single mechanical seal described above.

The present invention has been made to solve the problems described above, and an object of the present invention is to provide a double mechanical seal capable of transmitting the rotational force of the motor shaft to the seal face through the driving pin, rather than the bellows.

In addition, another object of the present invention is to provide a double mechanical seal that can maintain a constant surface pressure over the entire seal face regardless of the size of the motor shaft.

In addition, another object of the present invention is to provide a double mechanical seal that can be easily installed at no load without applying compressive force to the spring when the collar is fixed to the motor shaft.

In order to achieve the above object, the double mechanical seal according to the present invention is fixed to the case of the impeller side and the motor side, respectively, a pair consisting of a seat having a perturbation surface and a sealing member for sealing the case. And a collar fixed to the motor shaft, a plurality of driving pins protruding in the longitudinal direction of the motor shaft from both ends of the collar, a plurality of springs installed in the through-holes in the motor shaft longitudinal direction provided in the collar, And a pair of retainers installed at both ends of the spring and a pair of rotor parts fastened to one side of the retainer and having a perturbation surface, and having a perturbation surface. The groove corresponding to the shape of the distal end of the driving pin is provided, so that the distal end of the driving pin and the groove of the seal face are engaged with the motor shaft. It is characterized in that the rotational force of the motor shaft is transmitted to the seal face.

In this case, the driving pin is provided with a guide portion having a stepped portion smaller than the diameter of the distal end portion, the guide groove corresponding to the guide portion is formed on the outer periphery of the retainer, the retainer can be moved back and forth along the guide portion In addition, it is preferable that one side of the retainer and the side of the distal end may be in contact with each other to prevent separation / separation of the retainer from the driving pin.

In addition, it is preferable that the sum of the free length of the spring and the thickness of the pair of retainers is smaller than the inner gap between the distal ends.

According to an embodiment of the present invention as described above, first, since the rotational force of the motor shaft can be transmitted to the seal face through the driving pin, even in high temperature and high pressure conditions or large size, there is no fear of tearing the bellows and more stable It is possible to transmit the rotational force and to prevent leakage.

Second, by providing a plurality of springs, regardless of the size of the motor shaft can maintain a constant surface pressure over the entire seal face, there is an advantage of less risk of leakage and extend the life of the seal.

Third, the sum of the free length of the spring and the thickness of the pair of retainers is made smaller than the inner gap between the distal ends, so that the collar can be fixed at an appropriate position on the motor shaft without load, so that a single mechanical seal can be easily There is an advantage to install.

1 is a cross-sectional view of a conventional mechanical seal,
2 is a perspective view of the double mechanical seal in accordance with an embodiment of the present invention,
3 is an exploded perspective view of a double mechanical seal according to an embodiment of the present invention;
4 is a cross-sectional view of a double mechanical seal according to an embodiment of the present invention;
5 is a fastening state of the driving pin and the seal face according to an embodiment of the present invention,
6 is a fastening state of the driving pin and the retainer according to an embodiment of the present invention,
7A to 7E are cross-sectional views of installation stages of the double mechanical seal according to the exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to describe in detail enough to be able to easily carry out the invention by those skilled in the art to which the present invention belongs, This does not mean that the technical spirit and scope of the present invention is limited.

2 to 4 are combined perspective and exploded perspective and sectional views of the double mechanical seal 100 according to an embodiment of the present invention, Figure 5 is a drive pin 22 and the seal according to an embodiment of the present invention The fastening state diagram of the face 25 is shown.

The double mechanical seal 100 according to an embodiment of the present invention includes a pair of stator parts 10 and motor shafts 3 fixed to the case 1 and 2 on the impeller side and the motor side, respectively. It consists of a rotor portion 20 to rotate with.

The stator 10 is composed of a seat 11 and a sealing member in a ring shape so that the motor shaft 3 can pass therethrough. The seat 11 is provided with a perturbation surface 111 in which friction with the seal face 25 to be described later, the sealing member serves to seal the case (1, 2) and the O-ring 12 as shown in FIG. It may be configured as, or may be composed of a cup gasket 13 as shown in FIG. Type or arrangement of the sealing member may be configured and modified in various ways at the level of those skilled in the art.

The rotor unit 20 includes a collar 21, a driving pin 22, a spring 23, a retainer 24, and a seal face 25.

The collar 21 is fixedly installed on the motor shaft 3. The collar 21 is formed in a ring shape and is provided with a through hole at an outer circumference thereof to be coupled to the motor shaft 3 using a set screw. It is preferable.

The driving pin 22 is formed in the shape of a rod and protrudes in the longitudinal direction of the motor shaft at both ends of the aforementioned collar 21. It may be fastened with the collar by a separate fixing means, it may be molded integrally with the collar. Therefore, as the motor shaft 3 rotates, the collar 21 and the driving pin 22 also rotate together.

The spring 23 is installed in the through hole in the longitudinal direction of the motor shaft 3 provided in the collar 21, it is preferably composed of a plurality of multi-springs spaced at a predetermined interval. Therefore, regardless of the size of the motor shaft can maintain a constant surface pressure over the entire seal face 25, there is an advantage that the risk of leakage is reduced and the life of the seal is extended.

The retainer 24 is formed in a pair of ring shapes and is disposed at both ends of the spring 23 described above, and the elastic force of the spring 23 is applied to the seal face 25 which is agitated with the stator to be described later. It serves to deliver uniformly.

The seal face 25 has a perturbation surface 252 which is in friction with the seat 11 of the stator part 10 described above, and has a spring 23 which is installed through the collar 21. Sealing is made while pressing the sheet 11 by the elastic force. The material of the perturbation surface is selected by the corrosiveness of the fluid, the temperature of use, or the content of the abrasive material.In general, the stator (sheet) uses silicon carbide (SiC), which is a wear-resistant material, and the rotor (sealing face) has self-lubrication and thermal conductivity. And the carbon material (excellent processability) is mainly used.

On the other hand, the seal face 25 is rotated in conjunction with the motor shaft (3), the conventional mechanical seal transfers the rotational force to the seal face through the rubber bellows bellows under high temperature and high pressure conditions or large size Could be compromised. Therefore, the double mechanical seal according to the present invention, as shown, to form a groove 251 that can be engaged with the distal end 221 of the driving pin 22 on the outer circumference of the seal face 25, The pin 22 is configured to transmit the rotational force to the seal face 25. Therefore, the rotational force of the motor shaft can be more stably transmitted, which has the advantage of increasing durability.

6 is a state diagram of the coupling between the drive pin 22 and the retainer 24 of the double mechanical seal according to an embodiment of the present invention.

The drive pin 22 of the double mechanical seal according to an embodiment of the present invention is further provided with a guide portion 222 having a stepped portion smaller than the diameter of the distal end portion 221, the outer periphery of the retainer 24 It is preferable that the guide groove 241 corresponding thereto is formed.

As described above, while the distal end portion 221 of the driving pin 22 protruding from both ends of the collar 21 fixed to the motor shaft 3 and the groove 251 provided in the seal face 25 are fastened, the collar 21, the driving pin 22 and the seal face 25 is rotated in conjunction with the motor shaft (3). At this time, if the retainer 24 which transmits the elastic force between the seal face 25 and the spring 23 is also not rotated together, wear progresses due to friction with the seal face 25 or the spring 23, and thus There is a problem of shortening the life.

Accordingly, the stepped guide portion 222 is smaller than the diameter of the distal end portion 221 of the driving pin 22 so that the retainer 24 may be rotated together with the collar 21 and the seal face 25. It is provided, the outer periphery of the retainer 24 to be further provided with a guide groove 241 corresponding thereto. This allows the retainer to rotate together with the motor shaft and also to move back and forth in the longitudinal direction of the motor shaft along the guide portion.

On the other hand, the side of the distal end 221 provided on the drive pin 22 and one side of the retainer 24 may be in contact with each other, preventing the retainer 24 from being separated / detached from the drive pin 22. It is desirable to.

7A to 7E are cross-sectional views of installation stages of the double mechanical seal according to the exemplary embodiment of the present invention.

In the double mechanical seal according to the exemplary embodiment of the present invention, the sum L1 of the free length of the spring 23 and the thickness of the pair of retainers 24 is an inner gap L2 between the distal ends 221. It is preferable to form smaller than).

In the conventional double mechanical seal, when the collar is fixed to the motor shaft, the collar has to be fixed while compressing the spring so as to exert a predetermined surface pressure on the perturbed seal face. Therefore, two or more people had to work at the same time, there was also a problem that the fixing position of the collar that can apply the surface pressure required for the seal face varies depending on the operator.

On the contrary, in the present invention, the sum L1 of the free length of the spring 23 and the thickness of the pair of retainers 24 is smaller than the inner space L2 between the distal end portions 221, whereby the collar 21 ) Is fixed to the motor shaft 3, there is an advantage that can be fixed to the collar 21 in the desired position even under no load without pressing the spring 23. This will be described through the installation process of the double mechanical seal according to an embodiment of the present invention with reference to the drawings.

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First, the stator part 10 including the O-ring 12 serving as a sealing member and the seat 11 provided with a perturbation surface is fixed to the motor side case 1 (FIG. 7A).

Then, the seal face 25 and the collar 21 to which the spring 23, the driving pin 22, and the retainer 24 are fastened are provided. At this time, the sum L1 of the free length of the spring 23 and the thickness of the pair of retainers 24 is formed to be smaller than the inner gap L2 between the distal ends 221. It is possible to create a play (S) between (24) (Fig. 7b).

Thereafter, the rotor part 20 is brought into close contact with the stator part 10 in a fixed manner so that there is no play between the seal face 25, the retainer 24, and the spring 23. ) Is fixed to the motor shaft 3 (Fig. 7C). Therefore, when fixing the collar 21 at the proper position on the motor shaft 3, one person can be easily fixed even under no load without applying a separate compressive force to the spring 23.

Finally, after the remaining seal face 25 is installed (FIG. 7D), the installation is completed by pressing the stator portion 10 fixed to the impeller side case 2 while pressing it in the direction of the collar 21 (FIG. 7E). ).

As described above, the double mechanical seal 100 of the present invention drives the rotational force of the motor shaft 3 by using the distal end portion 221 of the driving pin 22 and the groove 251 on the seal face 25. Since it can be transmitted to the seal face 25 through the pin 22, there is no fear of tearing the bellows even under high temperature and high pressure conditions or in a large size, and there is an advantage that a more stable rotational force can be transmitted. By adjusting the free length, the collar 21 can be fixed at an appropriate position on the motor shaft 3 with no load, so that one person can easily install a double mechanical seal.

100: mechanical seal 1: motor side case
2: impeller side case 3: motor shaft
10: stator part 11: sheet
111: perturbation surface 12: O-ring
13 cup gasket 20 rotor part
21: collar 22: drive pin
221: distal end 222: guide part
23: spring 24: retainer
241: guide groove 25: seal face
251: groove 252: perturbation

Claims (3)

A pair of stator parts fixed to the case of the impeller side and the motor side, respectively comprising a sheet provided with a perturbation surface and a sealing member for sealing the case; and
A collar fixed to the motor shaft, a plurality of driving pins protruding in the longitudinal direction of the motor shaft from both ends of the collar, a plurality of springs provided in the through-holes in the longitudinal direction of the motor shaft provided in the collar, and both ends of the spring And a pair of retainers to be installed and a rotor part which is fastened to one side of the retainer and comprises a pair of seal faces provided with a perturbation surface.
The outer periphery of the seal face is provided with a groove corresponding to the shape of the distal end of the drive pin, the end of the drive pin rotated in conjunction with the motor shaft and the groove of the seal face is fastened so that the rotational force of the motor shaft with the seal face Double mechanical seal, characterized in that delivered.
The method of claim 1,
The driving pin is provided with a guide portion having a stepped portion smaller than the diameter of the distal end portion, a guide groove corresponding to the guide portion is formed on the outer periphery of the retainer,
The retainer may be moved back and forth along the guide portion, and the side of one end of the retainer and the distal end may be in contact with each other to prevent separation / separation of the retainer from the driving pin. Seal.
The method of claim 2,
The sum of the free length of the spring and the thickness of the pair of retainers is formed smaller than the inner gap between the distal ends.

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