JPH0615170Y2 - Sealing device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a sealing device, and in particular, when leakage occurs from a mechanical seal, it exerts an emergency sealing function by utilizing the pressure of the leaked internal fluid. Regarding those equipped with an emergency seal.

[Conventional technology]

2. Description of the Related Art Some sealing devices are designed to activate an emergency seal when various main seals such as mechanical seals lose their sealing functions. Conventionally, this kind of emergency seal is usually operated at the discretion of an operator.

[Problems to be Solved by the Invention] According to the above-mentioned conventional configuration, there is a problem that it is difficult to set a timing such as how much leakage occurs from the main seal to activate the emergency seal.

Therefore, there is a demand for a structure in which the sealing device itself has a self-acting type emergency seal, and when the main seal loses the sealing function, the emergency seal automatically operates.

An example of such a structure is shown in Japanese Patent Publication No. 39-2255. This is to provide a preliminary seal on the sealed space side of the main sealing mechanism, and when the main seal loses the sealing function, activate the preliminary seal by utilizing the pressure difference, thereby exerting an emergency sealing function.

However, according to such a configuration, it is difficult to reliably and promptly exert the emergency seal when leakage occurs from the main seal, and further improvement has been required.

The present invention has been made based on such a point, and an object of the present invention is to provide a self-acting type sealing device capable of promptly and reliably exhibiting an emergency sealing function. .

[Means for Solving the Problems]

In order to achieve the above object, the present invention is a sealing device including a main mechanical seal provided on the fluid side to be sealed and an emergency seal provided on the atmospheric side of the main mechanical seal. A fixed ring that is airtightly supported on the inner periphery of the housing, and a rotating ring that is airtightly supported on the outer periphery of a rotary shaft that is rotatably arranged through the inner periphery of the housing and that slides closely with the fixed ring. The emergency seal includes a second rotary ring that is airtightly fixed to the outer circumference of the rotary shaft, and an airtight seal that is located on the main mechanical seal side of the second rotary ring and that is on the inner circumference of the housing. And a labyrinth ring which is normally arranged to be movable in the axial direction and which includes a second rotary ring and a non-contact labyrinth ring. main Is obtained by a structure formed by opening a drain hole faces the upper portion of the shaft circumference space between Kanikarushiru and emergency seal.

[Action]

In the above configuration, when the sealing function of the main mechanical seal is normally exerted, in the emergency seal, the labyrinth ring is not in contact with the second rotary ring. Also,
The labyrinth groove on the inner periphery of the labyrinth ring has a non-contact type labyrinth seal function with the outer peripheral surface of the rotating shaft.

However, if the sealing function of the main mechanical seal deteriorates and the leak amount exceeds the allowable leak amount by the labyrinth seal mechanism of the labyrinth ring, the shaft circumference between the main mechanical seal with a drain hole in the upper part and the emergency seal will increase. The fluid leaking from the main mechanical seal accumulates in the space and its pressure (head) rises, so the labyrinth ring is pressed axially by this pressure and comes into close contact with the second rotary ring, and the emergency seal is the labyrinth ring. The non-contact sealed state due to the contact with the second rotary ring shifts to the sliding sealed state due to the close contact with the second rotary ring. The leaked fluid, which has been prevented from flowing out of the machine by the emergency seal and accumulated in the shaft circumferential space, is recovered by overflowing from the drain hole opened in the upper part.

〔Example〕

An embodiment of the sealing device according to the present invention will be described below with reference to FIG.

That is, in FIG. 1, reference numeral 1 is a rotary shaft rotatably arranged in the inner periphery of the housing 3 containing the pressure fluid. A main mechanical seal interposed between the rotary shaft 1 and the housing 3, and a rotary ring 7 airtightly supported on the outer periphery of the rotary shaft 1 and a fixed ring 9 airtightly supported on the inner peripheral portion of the housing 3. The rotating ring 7 and the fixed ring 9 are in close contact with each other due to the urging force of an elastic member (not shown), and prevent the fluid 11 to be sealed in the machine from leaking from the shaft periphery. Reference numeral 13 in the drawing is a sleeve.

An emergency seal 1 is provided on the atmosphere side of the main mechanical seal 5.
5 are installed. The emergency seal 15 includes a sleeve collar 17 that is airtightly fixed to the sleeve 13 and serves as a second rotary ring, and a labyrinth ring made of a PTFE resin material disposed on the main mechanical seal 5 side of the sleeve collar 17. 19 and. Labyrinth ring 19
It is supported in the inner periphery of the housing 3 in an airtight manner and axially movably via a packing 21 which is fitted in an annular groove on the outer periphery of the housing 3 and is slidable on the inner periphery of the housing 3.

The inner peripheral surface of the labyrinth ring 19 is not in contact with the outer peripheral surface of the sleeve 13, and the labyrinth groove 23 is provided in this inner peripheral surface, which allows a kind of non-contact with the rotary shaft 1 side. It constitutes a labyrinth seal mechanism that is a seal. Further, the labyrinth ring 19 is prevented from rotating by a pin 27 fixed to the housing 3 by penetrating a flange 25 formed at the outer diameter end portion,
The end surface of the sleeve collar 17 is separated by a gap δ.

A drain hole 31 is formed in the housing 3 so as to face the upper portion of the axial circumferential space 29 between the main mechanical seal 5 and the emergency seal 15.

The operation will be described based on the above configuration.

First, when the main mechanical seal 5 normally performs the sealing function, as shown in the figure, the emergency seal 15 has a labyrinth ring 19 and the sleeve collar 17 has a gap δ.
Labyrinth ring 1 which is axially separated from
A labyrinth sealing function is provided between the labyrinth groove 23 of 9 and the sleeve 13. The main mechanical seal 5
Has a slight leak due to the lubricating action of the sliding surface even when its sealing function is normal, but since the labyrinth groove 23 is a non-contact type seal, the main mechanical mechanism is used at such a minute flow rate. It does not completely prevent the fluid leaking from the seal 5 into the space 29 from flowing out to the atmosphere side.

Next, the main mechanical seal 5 includes a rotary ring 7 and a fixed ring 9.
The sealing function of the sliding surface of the shaft deteriorates due to some reason such as progress of wear or damage of the sliding surface of the sliding surface of the shaft circumferential space 29.
If the amount of leakage of the fluid 11 to be sealed into the labyrinth groove 23 exceeds the permissible flow rate due to the labyrinth seal function, the shaft peripheral space 2 between the main mechanical seal 5 and the emergency seal 15
9 has an upper portion opened by the drain hole 31,
The leaked fluid from the main mechanical seal 5 is the axial space 2
Accumulated in 9. Therefore, the pressure of the shaft circumferential space 29 acting as a back pressure on the labyrinth ring 19 increases, and the labyrinth ring 19 is axially pressed by this pressure and comes into close contact with the facing end surface of the rotating sleeve collar 17. Therefore, the emergency seal 15 shifts from the non-contact seal state by the labyrinth seal mechanism to the sliding seal state by the close contact with the sleeve collar 17.

Therefore, from the main mechanical seal 5 to the shaft circumferential space 29
It is possible to reliably prevent the fluid leaked to the atmosphere from flowing out to the atmosphere side. Further, the fluid accumulated in the shaft peripheral space 29 due to the emergency seal 15 shifting to the sliding seal state overflows from the drain hole 31 and is collected in a collecting unit (not shown).

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a packing 2 in which a labyrinth ring 19 is axially movably supported on an inner circumference of a housing 3.
1 is mounted in an annular groove formed on the housing 3 side, and other configurations are similar to those of the first embodiment.

According to this structure, the packing 21 is in sliding contact with the outer peripheral surface of the labyrinth ring 19 made of PTFE, so that the axial movement of the labyrinth ring 19 can be further smoothed when the leakage flow rate from the main mechanical seal 5 increases. ,
That is, the emergency seal 15 can be shifted to the sliding seal state with higher responsiveness.

[Effect of device]

As described above in detail, the seal device according to the present invention is designed so that when the sealing function of the main mechanical seal deteriorates and the leakage amount exceeds the allowable leakage amount by the labyrinth seal mechanism provided in the emergency seal, Due to the pressure increase in the shaft peripheral space between the seal and the emergency seal, the emergency seal shifts from the non-contact seal state to the sliding seal state, and when leakage exceeds the predetermined flow rate from the main mechanical seal, It has an excellent effect that the emergency seal can surely function.

[Brief description of drawings]

FIG. 1 is a half cutaway view of a sealing device showing a first embodiment of the present invention, and FIG. 2 is a half cutaway view of a sealing device showing a second embodiment. 1 ... Shaft, 3 ... Housing 5 ... Main mechanical seal, 7 ... Rotating ring 9 ... Fixed ring, 15 ... Emergency seal 17 ... Sleeve collar (second rotating ring) 19 ... Labyrinth ring , 21 …… packing 23 …… labyrinth groove

Claims (1)

[Scope of utility model registration request] 1. A main mechanical seal provided on the side of a fluid to be sealed, and an emergency seal provided on the atmospheric side of the main mechanical seal, the main mechanical seal being airtightly supported on the inner peripheral portion of the housing. A fixed ring, and a rotary ring that is airtightly supported by the outer circumference of the rotary shaft that is rotatably arranged through the inner circumference of the housing and that slides closely against the fixed ring. A second rotary ring that is airtightly fixed to the second rotary ring, and is located on the main mechanical seal side of the second rotary ring on the inner circumference of the housing so as to be airtight and movable in the axial direction through a packing. Of the labyrinth ring and the non-contacting labyrinth ring, the labyrinth groove is provided on the inner peripheral surface of the labyrinth ring that is not in contact with the outer peripheral surface of the rotating shaft, and the housing is equipped with a shaft circumference Sky Sealing device being characterized in that opened a drain hole faces the top of the.