JP3008013B2 - Shaft sealing device for fluid equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for fluid equipment, and more particularly to volatile or low-boiling fluids such as liquid ammonia and hydrocarbons, and harmful substances such as cleaning agents and solvents commonly used in the chemical industry. The present invention relates to a shaft sealing device for a fluid device applied to a process pump, a stirrer, a compressor, and the like that handles a fluid containing a fluid.

[0002]

2. Description of the Related Art In this type of shaft sealing device for fluid equipment, when the above-mentioned internal fluid leaks into the atmosphere through a minute gap between the equipment casing and the rotating shaft, it is traced to a low concentration. Nevertheless, strict regulations are required for its leakage because inhalation for a long time may adversely affect health.

[0003] Conventionally, a shaft sealing device for a fluid device has been generally adopted. The device includes a casing and a rotating shaft penetrating the casing. A stationary sealing ring fixedly held on the device casing, a rotating sealing ring disposed opposite to the stationary sealing ring and held slidably in the axial direction on the rotating shaft; and And two sets of contact seals which are urged toward the stationary sealing ring side, and a sealing liquid such as oil or water is injected into a sealing chamber formed between these two sets of contact seals, A double or tandem type contact seal that shields the inside of the machine and the atmosphere side through the relative rotational sliding action of the two sealing rings of each contact seal and the sealing liquid injected into the sealing chamber. Shaft seal device It has been.

[0004] In addition to the shaft sealing device constituted by the double or tandem type contact seal as described above, as disclosed in Japanese Patent Publication No. 7-69018 and Japanese Patent Application Laid-Open No. 5-33871, A dynamic pressure type in which one of the two seals is a contact seal and the other is relatively rotated in a non-contact state by dynamic pressure generated through a dynamic pressure generating groove formed in an end face of the rotary seal ring. Non-contact seals, JP-A-7-71613 and JP-A-6-161
As seen in Japanese Patent Application Laid-Open No. 74108 and the like, there is also known a type in which two sets of seals are both dynamic pressure type non-contact seals.

[0005]

However, among the above-mentioned prior arts, in the shaft sealing device for a fluid device which is constituted by a double or tandem type contact seal, there are two types.
The end faces of both seal rings of each pair of contact seals are in sliding contact with each other, causing not only severe wear and extremely short service life, but also the fluid lubricating film formed between the end faces of both seal rings due to sliding heat. As a result, the sealing function tends to deteriorate, and the sealing liquid leaks to the sealed fluid side in the machine or leaks to the atmosphere, so that the reliability of the seal as a whole is low. In addition, in order to prevent the temperature of the sealing liquid from gradually increasing due to the sliding heat, a sealing liquid circulating supply system using a cooler is required, and there is a problem that the structure of the entire apparatus is complicated and the cost is increased.

Further, in a shaft sealing device for a fluid device in which a contact seal and a dynamic pressure type non-contact seal are combined, or where two sets of seals are both dynamic pressure type non-contact seals, a double or tandem type contact seal is used. Since at least one of them is a non-contact seal as compared with the one using a seal, the overall degree of wear can be reduced and the service life can be improved, but since the non-contact seal is a dynamic pressure type, fluids such as pumps The torque required when starting or stopping the equipment is large, so fluid equipment such as a pump with a small power source that has been installed conventionally requires replacement of the power source and cannot be applied as it is . In addition, the dynamic pressure type non-contact seal is liable to deteriorate the sealing performance due to breakage or wear of the end face of the sealing ring mainly at the time of starting the equipment. Therefore, two sets of the dynamic pressure type non-contact seal are doubled. Even if it is arranged, the sealing performance of both of them will be reduced at an early stage, and it will not be possible to exert a stable sealing function in long-term use, the reliability of the seal is insufficient, and severe Leakage regulations cannot be met.

[0007] In addition, the above-mentioned conventional shaft sealing device for a fluid device is provided at two locations on the inside of the machine and on the atmosphere side, which are spaced apart in the axial direction between the machine casing and the rotating shaft penetrating the machine casing. Since the contact seal and / or the dynamic pressure type non-contact seal are respectively arranged in a double or tandem form, the whole can be easily enlarged in the axial direction of the rotating shaft, and is particularly already assembled in a plant or the like. It cannot be applied to a fluid device as it is, and if it is to be applied, there is a problem that the entire plant must be largely remodeled.

Accordingly, the present invention has been made in view of the above circumstances, and it is possible to improve the service life by reducing the degree of wear, to save energy by reducing the torque, and to expand the applicable range. An object of the present invention is to provide a shaft sealing device for a fluid device which can exhibit a reliable and stable sealing function comparable to that of a double or tandem type while reducing the size of the entire device by using a shape seal.

[0009]

In order to achieve the above object, a shaft sealing device for fluid equipment according to claim 1 of the present invention is provided between an equipment casing and a rotating shaft passing through the equipment casing. A rotary seal ring that rotates with the rotary shaft, and an annular member that is disposed opposite to the rotary seal ring and is fitted and fixed to the casing for the device, and is slidably held in the axial direction via a plurality of O-rings . With a stationary sealing ring,
And a shaft seal device for a fluid device configured by disposing a non-contact seal configured to press and urge the stationary seal ring from the atmosphere side to the rotary seal ring side, wherein the stationary seal in the non-contact seal is provided. Grooves are formed on the end face of the ring in three stages at intervals in the radial direction along the circumferential direction of rotation, and among these circumferential grooves, the radially outermost circumferential groove and the radially innermost circumferential groove are located. A gas supply hole which communicates with the circumferential groove and supplies gas pressure toward the end face of the rotary seal ring to keep the end faces of both seal rings in a non-contact state, and a circumferential groove located in the middle in the radial direction. a gas vent hole for discharging the supplied communicated between the end faces of both seal rings gas to the outside of the predetermined portion it
Re the stationary seal ring, and is characterized in that it is formed in the annular member and the pump casing.

That is, the flow according to the first aspect of the present invention.
According to the body device shaft sealing device, the radially outermost circumferential groove and the radially outermost groove among the grooves along the rotational circumferential direction formed on the end face of the stationary sealing ring at three radially spaced steps. The gas pressure supplied to the inner circumferential groove through the gas supply hole keeps the end faces of both sealing rings in a non-contact state, and the gas pressure is supplied more than the radially outermost circumferential groove. The sealing surface formed by the end face portion of the radially outer stationary sealing ring and the end face portion of the stationary sealing ring opposed thereto prevents leakage of the fluid to be sealed, and prevents any leakage from the sealing face. The end face of the stationary sealing ring radially inward of the radially outermost circumferential groove and radially inward of the radially intermediate circumferential groove through which the gas vent hole communicates, and the stationary sealing ring opposed thereto. Seat formed by the end face of the ring While sealing a plane it is possible to discharge to the outside of the predetermined portion through the gas vent hole.
Therefore, since it is a static pressure type non-contact seal, the degree of wear on the end faces of both sealing rings is reduced, the service life is extended, the sealing function is not reduced by sliding heat, and the starting torque is halved. It is possible to save energy and improve the seal reliability as a whole,
There is no need for a liquid sealing and circulating supply system using a cooler, so that the structure of the entire apparatus can be simplified and the cost can be reduced.

[0011] In addition, as described above, it is possible to exert the same function as the double or tandem type seal even though it is a single type seal using a single static pressure type non-contact seal. In addition, it is possible to reliably prevent leakage of the sealed fluid while reducing the size of the entire apparatus.

Further, at least four stages of sealing functions can be performed in the radial direction between the end surfaces of the two sealing rings, and leakage of the sealed fluid can be more reliably prevented.

[0013] In the shaft sealing device for a fluid device having the above-described structure, the gas pressure supplied to the circumferential groove through the gas supply hole may be higher than the pressure of the fluid to be sealed of the fluid device. It is also desirable that the pressure is set to 0.5 kgf / cm ² or more, and furthermore, the gas discharged from the gas vent hole is subjected to an extinguishing process so that the amount of the gas is reduced to a very low level. The adverse health effects associated with the release of gas containing concentrated fluid to the atmosphere can be avoided.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half-section longitudinal sectional view when a shaft sealing device for a fluid device according to the present invention is applied to a shaft sealing device for a pump. In FIG. 1, reference numeral 1 denotes a pump casing of, for example, a process pump. The pump casing 1 penetrates the inside M and the atmosphere side N, and an impeller (not shown) is fixed to the inside M. Rotating shaft 2
Are rotatably supported, and a shaft sleeve 3 is externally fitted to the rotating shaft 2 so as to be integrally rotatable. Reference numeral 4 denotes a static pressure type non-contact seal provided between the rotary shaft 2 and the pump casing 1.

The static pressure type non-contact seal 4 is fixed and held by a shaft sleeve 3 fitted externally to the rotating shaft 2 and
Rotating seal ring 5 that rotates with
And a stationary sealing ring 8 slidably held in an axial direction via a plurality of O-rings 7 on an annular member 6 fixed to the inside of the pump casing 1 and fixed to the pump casing 1. 8 is urged from the atmosphere side N to the rotary seal ring 5 side via a spring 9.

As shown in FIG. 2, the end face 8a of the stationary sealing ring 8 in the static pressure type non-contact seal 4 is intermittently interrupted along the rotational circumferential direction at three stages with a radial interval therebetween. The arc-shaped grooves 10a, 10b, and 10c are formed, and the arc-shaped groove 10 located at the outermost side in the radial direction is formed.
a and the innermost arc-shaped groove 10c are opened to communicate with the end face 5a of the rotary seal ring 5 by 0.5 from the pressure of the sealed fluid sealed in the inside M of the machine.
An orifice hole 11 serving as a gas supply hole for supplying a buffer gas having a pressure higher than kgf / cm ² or more, for example, N ₂ gas, to keep the end faces 5a, 8a of both sealing rings 5, 8 in contact with each other has a stationary sealing ring. 8 and this orifice hole 1
1 is formed in the annular member 6 and the pump casing 1, while the gas supply holes 12 communicate with the arc-shaped grooves 10b located in the middle in the radial direction so as to communicate with the end faces of the sealing rings 5, 8. Gas vent holes 13 and 1 for discharging the gas supplied between 5a and 8a to a predetermined location outside the pump casing 1, for example, to a collection and cancellation processing unit (not shown).
4 is formed on the stationary sealing ring 8, the annular member 6, and the pump casing 1. It is desirable to form a labyrinth seal between the rotary shaft 2 on the atmosphere side N and the pump casing 1 to enhance the sealing effect.

In the pump shaft sealing device constructed as described above, the seal disposed between the pump casing 1 and the rotary shaft 2 is a non-contact type seal 4 of a static pressure type. The degree of wear of the rotating seal ring 5 of the seal 4 and the end faces 5a, 8a of the stationary seal ring 8 is reduced, so that the service life can be extended and the sealing function does not decrease due to sliding heat. It is possible to improve the performance and to reduce the starting torque by half by making the end faces 5a and 8a of the rotating and stationary sealing rings 5 and 8 in a non-contact state at the time of starting and stopping the pump. Further, a liquid-circulating supply system using a cooler is not required, so that the structure of the entire apparatus can be simplified and the cost can be reduced.

In addition, the end face of the stationary sealing ring 8 radially outside the arc-shaped groove 10a through which the high-pressure buffer gas is supplied through the gas supply hole 12 and the orifice hole 11, and the stationary sealing ring 5 opposed thereto. Leakage of the sealed fluid is prevented by the sealing surface A formed by the end surface portion, and in the unlikely event of leakage from the sealing surface A, a gas discharge hole is provided inside the arc-shaped groove 10a. The stationary sealing ring 8 radially inside the middle arc-shaped groove 10b with which the communication ring 13 communicates.
Seal surfaces B and C and an arc-shaped groove 10c formed by an end surface portion of
The gas containing an extremely small amount of leaked fluid is discharged through a gas vent hole while being sealed with a sealing surface D formed by the end face portion of the stationary sealing ring 8 located radially inside and the end face portion of the stationary sealing ring 5 opposed thereto. It is possible to discharge the waste to an external collection / removal processing unit through the 13 and 14 for disposal, and it is possible to use a single-type seal to achieve almost the same sealing performance as a double or tandem-type seal. Such a leaked fluid is not released to the atmosphere, so that adverse effects on health can be avoided.

FIG. 3 is a half sectional vertical sectional view showing another embodiment of the pump shaft sealing device shown in FIGS. 1 and 2. The end face 8 of the stationary sealing ring 8 in the static pressure type non-contact seal 4 is shown.
a, arc-shaped grooves 10a, 10b, 10c formed in three stages at intervals in the radial direction are alternately arranged in the rotating circumferential direction so that they do not linearly overlap each other in the radial direction. The orifice hole 11 is penetrated by making the orifice hole 11 penetrate the outermost arc-shaped groove 10a and the innermost arc-shaped groove 10c, respectively, and is communicated with the arc-shaped groove 10b positioned radially inward. Since the gas vent hole 13 is formed and the other configuration is the same as that of FIG. 2, the corresponding portions are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the pump shaft sealing device constructed as shown in FIG. 3, since the orifice hole 11 and the gas vent hole 13 do not linearly overlap in the radial direction, the end surfaces 5a, The gas supplied between 8a is not immediately discharged to and collected by a collection / cancellation processing unit (not shown) outside the pump casing 1, so that the gas functions more effectively as a barrier against the sealed fluid. . In addition, the leaked fluid is likely to leak from the area where the gas vent hole 13 is provided, and the discharge and recovery of the leaked fluid is ensured.

FIG. 4 is a longitudinal sectional view showing another embodiment of the shaft sealing device for the pump shown in FIGS. 1 and 2 and shows a stationary sealing ring 8 in the static pressure type non-contact seal 4. Of the grooves 10a, 10b, and 10c formed in the inner face and the outer three steps on the end face 8a at intervals in the radial direction, a radially intermediate groove 10b in which the gas vent hole 13 is formed to communicate is formed in a circumferential shape. Since other configurations are the same as those in FIGS. 2 and 3, the same reference numerals are given to the corresponding portions, and detailed description thereof will be omitted.

In the pump shaft sealing device constructed as shown in FIG. 4, the groove 10 for communicating with the gas vent hole 13 is formed.
Since b is formed in a circumferential shape, all of the sealed fluid leaking in the radial direction passes through the area of the circumferential groove 10b, and the discharge and recovery of the leaked fluid is further ensured.

[0023]

As described above, according to the first to third aspects of the present invention, the use of a static pressure type non-contact seal reduces the degree of wear of the end faces of both sealing rings, thereby shortening the service life. In addition to extending the power and reducing the starting torque by half to save energy, the sealing function does not decrease due to sliding heat and the overall sealing reliability can be improved.
A sealing liquid circulation supply system using a cooler is not required, so that the structure of the entire apparatus can be simplified and the cost can be reduced.

In addition, although a single type seal using a single static pressure type non-contact seal, a sealing function comparable to that of a double or tandem type seal can be exerted. It can be easily applied to fluid equipment installed in plants and other facilities without requiring major modifications, etc., while reliably and stably preventing leakage of sealed fluid. It has the effect that it can be done.

In particular, according to the third aspect of the present invention, in addition to the above-mentioned effects, even if a small leak occurs in the sealed fluid, the leak is removed together with the gas discharged from the vent hole. It is also possible to avoid the adverse effects on health due to the release of a gas containing a trace amount and low concentration of the sealed fluid into the atmosphere.

[Brief description of the drawings]

FIG. 1 is a half sectional vertical side view showing a configuration of a pump shaft sealing device to which a fluid device shaft sealing device according to the present invention is applied.

FIG. 2 is a half sectional vertical front view taken along line YY of FIG. 1;

FIG. 3 is a half sectional vertical front view showing another embodiment of the shaft sealing device for a pump in FIGS. 1 and 2;

FIG. 4 is a longitudinal sectional front view showing another embodiment of the shaft sealing device for a pump in FIGS. 1 and 2;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 pump casing (equipment casing) 2 rotating shaft 4 non-contact seal 5 rotating seal ring 8 stationary seal ring 10 a, 10 b, 10 c arc-shaped groove (circumferential groove) 11 orifice hole (gas supply hole) 12 gas supply hole 13 , 14 Gas vent hole M Inside machine N Atmospheric side

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16J 15/00-15/14

Claims (3)

(57) [Claims] 1. A rotary sealing ring that rotates together with the rotating shaft between an equipment casing and a rotating shaft that penetrates the equipment casing, and is disposed to face the rotating sealing ring and is fitted and fixed to the equipment casing. a plurality of O-the annular member which is
And a stationary seal ring held axially slidably through the ring and the stationary seal ring disposed non-contact seal formed by pressed and urged from the atmosphere side to the rotary seal ring side A fluid sealing device for a fluid device, comprising: a groove formed along the rotational direction in three stages at radially spaced intervals on an end face of the stationary sealing ring in the non-contact seal; The gas is supplied to the end face of the rotary seal ring by communicating with the radially outermost circumferential groove and the radially innermost circumferential groove of the directional grooves, and a gap is formed between the end faces of the two seal rings. The gas supply hole for maintaining the contact state and the gas vent hole communicating with the circumferential groove located in the middle in the radial direction and discharging the gas supplied between the end faces of both sealing rings to a predetermined external location are respectively described above. Stationary sealing ring , annular member
And a shaft sealing device for a fluid device formed on a pump casing . 2. The fluid according to claim 1, wherein a gas pressure supplied to the circumferential groove through the gas supply hole is set to be 0.5 kgf / cm ² or more higher than the pressure of the sealed fluid of the fluid device. Shaft sealing device for equipment. 3. The shaft sealing device for a fluid device according to claim 1, wherein the gas discharged from the gas vent hole is configured to be eliminated.