JPH0614145Y2 - Double mechanical seal type shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a double mechanical seal type shaft sealing device having two sets of mechanical seals.

[Conventional technology]

When a double mechanical seal type shaft sealing device with two sets of mechanical seals is used to seal the shaft circumference of a device, if both mechanical seals are arranged in the axial direction and assembled, the entire shaft sealing device The mounting length in the axial direction becomes very long,
As described in the publication, one mechanical seal is arranged on the inner diameter side and the other mechanical seal is arranged on the outer diameter side so as to overlap each other, and the rotary rings of both mechanical seals are supported by a common collar. By adopting a structure in which the springs are biased in the same direction and slidably contact the non-rotating fixed rings, the axial mounting length can be greatly shortened.

[Problems to be solved by the device]

However, according to the above-described conventional structure, the springs of both mechanical seals are supported by a common collar to urge the rotating ring in the same direction, so that a large thrust load is applied to the rotating shaft by its reaction, and When the pressure of the fluid supplied to the space between both mechanical seals is high, this pressure acts in the direction to open the sliding surface of the mechanical seal on the outer diameter side, and there is a problem that leakage easily occurs.

The present invention has been made in view of the above problems, and an object thereof is to significantly reduce the axial mounting length of a double mechanical seal type shaft sealing device, and to rotate the rotating shaft in one direction. There is no thrust load that would cause a displacement, and the structure has excellent sealing performance.

[Means for Solving the Problems]

In order to solve the above problems, a double mechanical seal type shaft sealing device according to the present invention comprises two sets of mechanical seals, an inner diameter side and an outer diameter side, and the inner diameter side mechanical seal is
A first fixed ring fitted to one casing side, a first rotary ring axially movable around the outer circumference of the rotary shaft via a first packing, and a biasing force applied to the rotary ring. And a collar that supports the rear end of the spring, and a mechanical seal on the outer diameter side is defined by the outer diameter of the collar and the outer circumference of the first packing. The second rotary ring fitted to the flange at the tip of the tubular portion extending so as to cover the side space, the cartridge case fitted to the other casing, and the inner circumference having the second packing in this cartridge case. A second fixed ring supported movably in the axial direction via the second fixed ring and a second spring for urging the fixed ring to bring it into close contact with the second rotary ring.

[Action]

According to the configuration of the present invention, the two sets of mechanical seals are radially overlapped with each other, so that the axial mounting length is shortened,
The urging forces of the first spring in the mechanical seal on the inner diameter side and the second spring in the mechanical seal on the outer diameter side act in opposite directions in the axial direction with respect to the rotating shaft. There is no thrust load that displaces to the side.

Also, the pressure of the space sealed between both mechanical seals acts in the direction to press the first rotating ring of the inner diameter side mechanical seal against the first fixed ring, while the pressure of the second fixed ring of the outer diameter side mechanical seal. Is directed in the same direction as the first rotary ring, the pressure also acts on the second fixed ring in the direction of pressing against the second rotary ring. Even if is raised, the sealing sliding surfaces of both mechanical seals do not open.

〔Example〕

Hereinafter, the present invention will be described with reference to the illustrated embodiment.

A double mechanical seal type shaft sealing device 8 of the present embodiment shown in FIG. 1 seals the shaft circumference of a submersible pump as shown in FIG. 2, 1 is a motor casing of the submersible pump, and 2 is this motor. A pump casing 4 fixed below the casing 1 with bolts 3, 4 is a motor housed in the motor casing 1, 5 is connected to the motor 4, and is rotatably supported by bearings 7. The motor casing 1 and the pump casing It is a rotary shaft that penetrates the shaft hole 2 and rotates the impeller 6 in the pump chamber 2a. An oil chamber 11 in which lubricating oil is enclosed is formed between the motor casing 1 and the pump casing 2.

The shaft sealing device 8 is composed of two sets of mechanical seals 9 and 10 on the inner diameter side and the outer diameter side, and the mechanical seal 9 on the inner diameter side is fitted to the upper end portion of the shaft hole of the pump casing 2 via a cup gasket 26. The first fixed ring 20 worn,
A first rotary ring 21 is disposed on the outer periphery of the rotary shaft 5 via the first packing 22 so as to be movable in the axial direction, and a free end of the first packing 22 is fixed to the first rotary ring 21. Case 2 engaged with the first rotary ring 21 in the circumferential direction
3, the fixed end portion of the first packing 22 is fastened and fixed to the outer peripheral surface of the rotary shaft 5, and the drive ring 24 circumferentially engaged with the case 23 and the rotary ring 21 are connected to the case 2
3 and a first spring 25 that is pressed and urged from behind via the free end of the first packing 22 to be brought into close contact with the fixed ring 20.

Reference numeral 101 is a collar that supports the rear end of the first spring 25, the back surface of which is in contact with the end portion of the sleeve 102 that is mounted on the rotary shaft 5, and the O-ring 103.
The rotary shaft 5 is hermetically sealed. The collar 101 has a cylindrical portion 101a extending so as to cover the outer peripheral side space of the first packing 22 and the flange 10 at the tip thereof.
4 is integrally formed, and the mechanical seal 10 on the outer diameter side is arranged on the outer peripheral side of the tubular portion 101a.

The mechanical seal 10 on the outer diameter side includes a second rotary ring 109 fitted to the flange 104 of the collar 101 via a cup gasket 110 and an annular fitting portion 105 formed on the end surface of the motor casing 1. A cartridge case 106 that is airtightly fitted to the inner periphery, and a second fixed ring 108 that is fixed to the front end of the cartridge case 106 and is axially movably supported via a second packing 107. The second fixed ring 108, which is housed in the cartridge case 106, is pressed and urged from the rear via the spring holder 112 and the free end of the second packing 107 to be brought into close contact with the second rotary ring 109. The spring 111 is included.

Double mechanical seal type shaft sealing device 8 having the above configuration
Since the two sets of mechanical seals 9 and 10 overlap each other in the radial direction, the mounting length L is significantly shortened as compared with the case where both mechanical seals are arranged in the axial direction. Further, the first spring 25 in the mechanical seal 9 on the inner diameter side acts so as to press the rotating shaft 5 toward the motor casing 1 side via the collar 101, while the second spring 1 in the mechanical seal 10 on the outer diameter side.
Since 11 acts to press the rotary shaft 5 toward the pump casing 2 side via the second fixed ring 108, the second rotary ring 109, the cup gasket 110 and the collar 101, the rotary shaft 5 has an axial direction. Thrust load that displaces to one side does not occur.

Further, the mechanical seals 9 and 10 prevent water in the pump chamber 2a from entering the motor 4 side, and prevent lubricating oil in the oil chamber 11 from leaking to the pump chamber 2a side and the motor 4 side. It is a thing. Here, heat generation of the motor 4 during driving and the fixed ring 2 of both mechanical seals 9 and 10
Sealing sliding surfaces 9S, 1 of 0, 108 and rotary rings 21, 109
When the temperature in the oil chamber 11 rises due to the sliding heat at 0S, the pressure of the lubricating oil sealed in the oil chamber 11 rises, but this pressure is the first pressure in the mechanical seal 9 on the inner diameter side. The first fixed ring 2 is attached to the rotary ring 21.
It acts in the direction of increasing the close force to 0, and similarly,
In the mechanical seal 10 on the outer diameter side, the second fixed ring 108 acts on the second fixed ring 108 in the direction of increasing the close contact force with respect to the second rotary ring 109. Therefore, the sealing sliding surfaces 9S, 1
The leakage of the lubricating oil due to the opening of 0S does not occur.

[Effect of device]

As described above, according to the double mechanical seal type shaft sealing device of the present invention, the thrust that displaces the rotary shaft to one side in the axial direction is formed despite the structure in which the two sets of mechanical seals are overlapped in the radial direction. The load is not generated, and the sealed sliding surfaces of the mechanical seals do not open due to the pressure of the space sealed between the mechanical seals, and an excellent shaft sealing function is achieved.

[Brief description of drawings]

FIG. 1 is a half sectional view of a shaft sealing device in a mounted state showing an embodiment of the present invention, and FIG. 2 is a sectional view of a submersible pump in which the shaft sealing device is mounted. DESCRIPTION OF SYMBOLS 1 ... Motor casing 2 ... Pump casing 5 ... Rotation shaft, 9 ... Inner diameter side mechanical seal 10 ... Outer diameter side mechanical seal 20 ... First fixed ring, 21 ... First rotating ring 22 ... First packing 25 ... first spring, 101 ... collar 101a ... tubular part, 104 ... flange 106 ... cartridge case 107 ... second packing 108 ... second fixed ring 109 ... second rotary ring 111 ... second spring

Claims (1)

[Scope of utility model registration request] 1. A mechanical seal comprising two sets of an inner diameter side and an outer diameter side. The inner diameter side mechanical seal is provided with a first fixed ring fitted to one casing side and a first packing. A first rotating ring disposed on the outer periphery of the rotating shaft so as to be movable in the axial direction, a first spring for biasing the rotating ring to bring it into close contact with the first fixed ring, and supporting a rear end of the spring. The mechanical seal on the outer diameter side, including a collar, is a second rotary member fitted to a flange at the tip of a cylindrical portion extending from the outer diameter of the collar so as to cover the outer peripheral side space of the first packing. A ring, a cartridge case fitted to the other casing, a second fixed ring whose inner periphery is axially movably supported by the cartridge case via a second packing, and a biasing force applied to the fixed ring. Close to the second rotary ring The second double mechanical seal type shaft sealing device which comprises a spring for.