JP2580157Y2 - Rotary shaft sealing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft sealing device applied to a compressor, a blower, a pump, a turbine and the like.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of a conventional rotary shaft sealing device used for a compressor or the like. In the figure, the sealing device has a seal oil head tank 5 installed at a position higher than the main body of the compressor, and a gas side above the head tank 5 is connected to a gas pressure extraction line 6 of the compressor. The seal oil side below the head tank 5 is connected to a seal oil supply line 7. The level controller 8 is set so that the oil level H of the head tank 5 is always kept constant.
Is controlled by Therefore, supply pressure P ₂ of the seal oil supplied to the seal housing 4 through the seal oil supply hole 4a is differential pressure P corresponding to the oil level height of the head tank 5 than the gas pressure P ₁ in the compressor ₂ −P ₁ = γ · H
(Γ is the specific weight of the seal oil).

The seal housing 4 is provided with an inner seal ring 2 and an outer seal ring 3 having a rectangular cross section. Before and after the inner seal ring 2, the above-described differential pressure γ
H is applied, so that a small amount of the seal oil leaks little by little from the gap with the rotating shaft 1 in the machine direction indicated by the arrow C. Normally, the pressure P ₃ outside the seal housing 4 is atmospheric pressure, but the supply pressure P ₂ of the seal oil is the gas pressure P inside the compressor.
Follow ₁ Therefore, when the operating condition of the compressor gas pressure P ₁ in the compressor varies, but also the outer seal ring 3 the differential pressure across P ₂ -P ₃ changes, the rotary shaft 1 by the pressure difference P ₂ -P ₃ outside The seal oil leaks little by little from the gap with the seal ring 3 to the outside of the machine as indicated by the arrow D. In this way, the compressor is sealed so that gas inside the compressor does not leak out of the compressor. In the figure, reference numeral 9 denotes a pressure balance line, and 10 denotes a balance connector.

[0004]

In the conventional rotary shaft seal device as described above, in the case of a recycle compressor for a methanol plant or a hydrogen recycle compressor for a petroleum refining plant by hydrodesulfurization, it is difficult to operate the compressor in normal operation. high gas pressure P ₁ of the compressor is therefore the supply pressure P of the seal oil
₂ is high, but the gas pressure P in the compressor during the catalytic reduction operation
₁ is lowered, thus supplying the pressure P ₂ of the seal oil is also low. For example, during normal operation, the gas pressure in the compressor P ₁ =
200 kgf / cm ² g, seal oil supply pressure P ₂ = 200.3
Even 5kgf / cm ² g, the gas pressure of the compressor at the time of the catalytic reduction operation ^{_{P 1 = 10.0kgf / cm 2 g}} , may be such as supply pressure P ^₂ = 10.35kgf / cm ₂ g of the seal oil is there. With such supply pressure P ₂ of the seal oil is lowered, the rotary shaft 1
The amount of seal oil passing through the gap between the outer seal ring 3 and the outer seal ring 3 is reduced, and the temperature of the outer seal ring 3 may increase due to frictional heat or the like in this gap and seizure may occur.

In order to prevent seizure of the outer seal ring 3, a seal oil bypass system such as a seal oil bypass hole 4b and a seal oil bypass valve 4c is provided in the seal housing 4 so that the seal oil is allowed to flow out and the outer seal ring is actively sealed. Although the ring 3 is cooled, this seal oil bypass system complicates the structure and control of the present seal device, resulting in high equipment costs and the like. In addition, the outer seal ring 3
When the gap between the outer seal ring 3 and the rotary shaft 1 is increased to increase the amount of seal oil in order to prevent seizure of the seal, the amount of seal oil increases during normal operation, and the size of the seal device is increased, resulting in increased equipment cost and Maintenance costs become expensive.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary shaft sealing device for supplying a seal oil into a seal housing provided around a rotary shaft. In a rotary shaft sealing device that leaks the seal oil out of the machine through a gap between the seal ring fitted to the rotary shaft and the rotary shaft and seals gas in the machine, the rotary shaft is engraved on the inner side surface of the seal ring. It is characterized by having a plurality of grooves for reducing the rigidity inside the machine.

[0007]

That is, in the rotary shaft sealing device according to the present invention, the seal oil is supplied into a seal housing provided around the rotary shaft, and the seal ring and the rotary shaft fitted to the rotary shaft in the seal housing are provided. A plurality of grooves are cut on the inside surface of the seal ring in the rotary shaft sealing device that seals gas inside the machine by leaking seal oil out of the machine from the gap of the outside, so that the rigidity inside the machine is reduced, and the outer seal ring Is small on the inside of the machine and large on the outside of the machine, but the rigidity of the seal ring is small on the inside of the machine where the groove is formed. As a result, the deformation of the seal ring due to the supply pressure of the seal oil becomes uniform, the difference between the inner clearance and the outer clearance between the rotary shaft and the seal ring becomes uniform, and the gas pressure inside the device increases as the gas pressure increases. The characteristic that the gap becomes small is obtained. Therefore, even if the gap between the seal ring and the rotary shaft is provided larger than before, if the supply pressure of the seal oil increases, the seal ring deforms more than before, and the gap between the rotary shaft and the seal ring becomes smaller. The supply oil amount of the seal oil is averaged. Also, when the supply pressure of the seal oil decreases, the deformation of the seal ring decreases,
By providing a larger gap between the rotating shaft and the seal ring than before, the amount of seal oil required for cooling such as frictional heat can be secured. Therefore, it is possible to seal the rotating shaft even at a lower supply pressure of the sealing oil than before.

[0008]

1 to 3 are explanatory diagrams of a rotary shaft sealing device according to an embodiment of the present invention. In the figure, the rotary shaft sealing device according to the present embodiment is applied to a compressor, a blower, a pump, a turbine, and the like. A seal oil head tank 5 is installed at a position higher than a main body of the compressor, The gas side above the head tank 5 is connected to a gas pressure extraction line 6 of the compressor, and the seal oil side below the head tank 5 is connected to a seal oil supply line 7. The oil level height H of the head tank 5 is controlled by the level controller 8 so as to be always kept constant. Therefore, supply pressure P ₂ of the seal oil supplied to the seal housing 4 through the seal oil supply holes 4a are compressor of the gas pressure P
Differential pressure P ₂ equivalent to the oil level of head tank 5 than ₁
−P ₁ = γ · H (γ is the specific weight of the seal oil) is supplied at a higher pressure.

A seal housing 4 is provided with an inner seal ring 2 and an outer seal ring 3 having a rectangular cross section. Before and after the inner seal ring 2, the above-described differential pressure γ
H is applied, so that a small amount of the seal oil leaks little by little from the gap with the rotating shaft 1 in the machine direction indicated by the arrow C. Normally, the pressure P ₃ outside the seal housing 4 is atmospheric pressure, but the supply pressure P ₂ of the seal oil is the gas pressure P inside the compressor.
Follow ₁ Therefore, when the operating condition of the compressor gas pressure P ₁ in the compressor varies, but also the outer seal ring 3 the differential pressure across P ₂ -P ₃ changes, the rotary shaft 1 by the pressure difference P ₂ -P ₃ outside The seal oil leaks little by little from the gap with the seal ring 3 to the outside of the machine as indicated by the arrow D. In this way, the compressor is sealed so that gas inside the compressor does not leak out of the compressor. In the figure, reference numeral 9 denotes a pressure balance line, and 10 denotes a balance connector.

Further, in the present rotary shaft sealing device, the working limit pressure of the outer seal ring 3 is reduced by effectively utilizing the deformation of the outer seal ring 3 due to the pressure distribution around the outer seal ring 3, and the compression is performed. Even if the gas pressure inside the machine increases, the amount of seal oil leaking out of the machine does not increase. That is, as shown in FIGS. 2 (a) and 2 (b), a plurality of deep grooves A having an L-shaped bottom are formed on the inner side surface of the outer seal ring 3 or as shown in FIGS. 2 (c) and 2 (d). A plurality of tapered grooves B whose bottoms are inclined are provided. The deep groove A and the tapered groove B are respectively provided at equal intervals on the inner side surface of the outer seal ring 3 so as to be cut out in the radial direction from the outer peripheral portion, and l ₁ / l ₂ = 0.3 to
0.7, l ₃ / l ₄ = 1.5-3.5, l ₅ / l ₆ =
0.2-0.7, l ₇ / l ₈ = 1.0-3.0, θ ₁ =
10 degrees to 30 degrees, and θ ₂ = 10 degrees to 45 degrees.

[0011] differential pressure P _r1 -P _r2 radially in the outer seal ring 3, as shown in FIG. 3 has a large small outboard is inboard. Further, since the deep grooves A or the tapered grooves B are provided at equal intervals on the outer peripheral portion of the inner side surface of the outer seal ring 3, the rigidity of the outer seal 3 is small on the inside of the machine and large on the outside of the machine. By thus rigidity of the outer seal ring 3 is changed in the axial direction, uniformly deformed as shown by the dotted line by the outer seal ring 3 is provided a pressure P ₂ of the seal oil, and the rotary shaft 1 by the modification resulting inboard-side gap r ₂ and outboard gap difference the gap r _3, r ₄ becomes smaller with with increasing compressor of the gas pressure P ₁ becomes uniform characteristics between r ₄ of the outer seal ring 3 Can be Therefore, the outer seal ring 3 is also a gap between the rotation shaft 1 in advance provided greater than conventional, the supply pressure P ₂ of the seal oil increases the outer seal ring 3 and the rotary shaft 1 by increasing deformation than conventional The gap between the outer seal ring 3 and the outer seal ring 3 becomes smaller, and the supply oil amount of the seal oil is averaged. Also, becomes the deformation of the outer seal ring 3 small if the supply pressure P ₂ of the seal oil is lowered, by providing larger than the conventional gap between the rotary shaft 1 and the outer seal ring 3, the cooling of the friction heat The required amount of sealing oil is secured. Therefore,
A supply pressure P _2, even the rotating shaft 1 seal low seal oil than conventional can, if the minimum threshold supply pressure of the sealing oil in the sealing device and P _X, minimum threshold supply pressure in the conventional sealing apparatus P _X + P _Y , P _X / P
_Y = 0.15 to 1.5.

[0012] When from recycling compressor and hydrodesulfurization for methanol plants such as oil refining hydrogen recycle compressor for plant during normal operation, high gas pressure P ₁ of the compressor, thus the supply pressure of the seal oil also high, gas pressure P ₁ of the compressor is lowered during catalyst reduction operation, thus supplying the pressure P ₂ of the seal oil is also low. For example, during normal operation, the gas pressure in the compressor P ₁ = 200 kgf / cm ² g,
Even when the supply pressure P ₂ of the sealing oil is 200.35 kgf / cm ² g, the gas pressure P ₁ = 1 in the compressor during the catalytic reduction operation.
0.0 kgf / cm ² g, seal oil supply pressure P ₂ = 10.35
kgf / cm ² g. With such supply pressure P ₂ of the seal oil decreases, in the conventional rotation shaft seal device is reduced seal oil amount that passes through the clearance between the rotating shaft and the outer seal ring, the outer seal due to friction heat in the gap Although the temperature of the ring may increase and cause seizure, in this rotary shaft sealing device, the outer seal ring 3
A plurality of grooves are provided in the outer peripheral portion on the inner side of the machine to reduce the rigidity of the inner side of the machine, and the pressure acting around the outer seal ring 3 is effectively used, so that a wide range of gas pressure P _{1 in the} compressor is obtained.
, The supply amount of the seal oil is averaged, and even when the supply pressure P ₂ of the seal oil fluctuates, the rotary shaft 1 can be sealed without bypassing the seal oil.
This eliminates the need for a seal oil bypass system and large seal oil equipment, and simplifies the rotary shaft seal device.
The cost can be reduced and the reliability can be improved.

[0013]

The rotary shaft sealing device according to the present invention is configured as described above, and the rotary shaft can be sealed with a lower supply pressure of the seal oil than before. No equipment is required, and equipment and maintenance costs are reduced.

[Brief description of the drawings]

FIG. 1A is a system diagram of a rotary shaft sealing device according to an embodiment of the present invention, and FIG. 1B is a sectional view of a main part.

2 (a) and 2 (c) are perspective views of the outer seal ring, FIG. 2 (b) is a sectional view taken along line bb in FIG. 2 (a), and FIG. 2 (d) is FIG. It is dd sectional drawing in ().

FIG. 3 is an explanatory diagram of the operation.

FIG. 4 is a system diagram of a conventional rotary shaft sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Inner seal ring 3 Outer seal ring 4 Seal housing 4a Seal oil supply hole 5 Head tank 6 Gas pressure extraction line 7 Seal oil supply line 8 Level controller 9 Pressure balance line 10 Balance connector

Claims (1)

(57) [Scope of request for utility model registration] 1. A seal oil is supplied into a seal housing provided around a rotary shaft, and the seal oil is removed from a gap between the rotary shaft and a seal ring fitted to the rotary shaft in the seal housing. What is claimed is: 1. A rotary shaft sealing device for sealing a gas in a machine by leaking to the outside, comprising a plurality of grooves engraved on the inside surface of the seal ring to reduce rigidity inside the machine.