JP2511205B2 - Shaft seal 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 shaft seal device, and more particularly to improvement of a shaft seal device incorporating a dry gas seal.

[0002]

2. Description of the Related Art Dry gas seals are, for example, power
International 1987-2 (Chris Dickenson
, “Why fit dry running gas seals?”, POWER INT
ER-NATINAL 1987-2), a rotating ring and a stationary ring are provided, and the surface of the rotating ring facing the stationary ring is provided with a shallow spiral groove, and gas is supplied to these rings. On entry, the grooves direct the gas in the direction and compress the gas, whereby the increased gas pressure maintains the sealing gap between the rings.

Dry gas seals are used, for example, in shaft sealing devices for gas compressors. FIG. 2 shows a shaft seal device in a carbon dioxide centrifugal compressor. A shaft b that supports the impeller a is held by bearings c and d, and is sealed by labyrinth seals g and h and labyrinth seals j and k. Dry gas seals e and f are labyrinth seals g and h and labyrinth seals j and k, respectively.
It is located between . Room between dry gas seal e and labyrinth seal h and dry gas seal f
Labyrinth sheet - the room is between Le k, pressure switch m, n month flows, Doraigasushi - Le e or Doraigasushi - le f or both Doraigasushi - Le e,
When f becomes abnormal and the amount of leak suddenly increases, pressure rises in these rooms are detected, alarms and warning lights are activated, and compressor operation is automatically shut down. are doing.

[0004]

Thus, the conventional shaft seal device is thus provided only when the leak from the dry gas seal exceeds the allowable limit, that is, after or just before the occurrence of the accident. It only gives an alarm or shuts down the system automatically. If changes in the amount of leak from the dry gas seal are monitored in detail-
Is as long as it can be, Doraigasushi - Ki out to know Le of the abnormality in advance, dry Gasushi - until the accident in Le occurs, perform preventive maintenance. However, since the gas constantly leaks from the labyrinth seal, dry gas seal
Since the absolute amount of leaks from the dry gas seal cannot be measured, it is not possible to monitor the dry gas seal in the sense of preventive maintenance, and the leak guaranteed by the manufacturer of the dry gas seal is not only possible. Even the amount cannot be actually confirmed.

An object of the present invention, Doraigasushi - by measuring the click amount, dry Gasushi - - Actual Li in Le is to provide a shaft sealing device in which the preventive maintenance Le on the line of obtaining such.

[0006]

In the shaft sealing device of the present invention, a shaft is sealed by a labyrinth seal and a dry gas seal which are sequentially arranged from a bearing side supporting the shaft, and the shaft is adjacent to the dry gas seal. labyrinth sheet - the shaft seal the bearing side Le is open to the atmosphere, the labyrinth sheet - le of the dry gas <br/> sheet - signal based on the difference between the pressure and the bearing-side pressure of the Le side < first means for generating br /> No., the signal from the first means
Based, wherein Doraigasushi - the Le labyrinth sheet -
Second means for obtaining and displaying the amount of leakage into the
And are characterized.

The shaft sealing device of the present invention comprises a third means for outputting a signal when the signal from the second means has a magnitude related to a value exceeding the amount of leak permitted by the dry gas seal. <br/> Can be provided. The third means may be connected to means for automatically shutting down the system in which the bearing device is incorporated, means for issuing a warning, or both. These means are, for example, a level transmitter in which the first means outputs an air pressure signal related to the differential pressure, and the second means displays the leak amount by the air pressure signal from the level transmitter and the differential pressure. A receiver for outputting an air signal associated with the pressure gauge, a third means for operating the pressure switch operated by an air pressure signal output from the receiver, and a fourth means for alarming or warning. Each is composed of lights.

The shaft sealing device of the present invention may further comprise a fifth means for making the chamber for accommodating the bearing have a negative pressure when the rotation of the shaft is stopped. Fifth means, for example, and the like exhaust blower or a vacuum pump connected to a drain piping system of the lubricating oil against the bearing.

[0009]

[Action] When the shaft seal device is employed for example, gas compressors, the compressor is operated, Doraigasushi - Le KARARI - click to gas Doraigasushi - is flow Le - Labyrinth sheet adjacent to the Le this gas labyrinth sheet - flows to the bearing side through the clearance between Le and the shaft, a dry Gasushi <br/> - labyrinth adjacent to Le sheet - bearing side pressure Le and Doraigasushi - between Le side pressure Differential pressure is generated.

In the shaft sealing device of the present invention, the first means
Measures the pressure difference between the bearing side pressure and the dry gas seal side pressure of the labyrinth seal and outputs a signal related to this pressure difference. The second means indicates the differential pressure by the signal from the first means. The displayed differential pressure can be converted into the flow rate of the labyrinth seal, that is, the amount of gas leaked from the dry gas seal, by the physical property formula. Dry gas sheet
Li from Le - by converting the Kugasu amount Doraigasushi - playable rows click to gas volume monitoring - actually Li Le.

[0011] The room housing the bearing is provided with a means for negative pressure, not only in operation, by Kassel work found the means even after stopping, Doraigasushi - to the room housing the bearings from Le The air flow of
Lubricating oil or lubricating oil mist against the bearing Doraigasushi - to prevent from entering the Le, Doraigasushi - the reliability of the Le can further high Mel it.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the shaft sealing device of the present invention will be described below with reference to FIG .

[0013] The shaft sealing device, in shall use the centrifugal compressor of carbon dioxide, 10 impeller 11 holding the impeller 10
The shafts to carry are shown. Shaft 11 of
Both ends are supported by bearings 12 and 13. The labyrinth seals 14 to 16 are arranged on one side of the impeller 10 and the labyrinth seals 17 to 19 are arranged on the opposite side of the impeller 10, and are fixed to a casing 31 of this centrifugal compressor. Furthermore, Doraigasushi - Le 20 labyrinth sheet - between Le 15, Doraigasushi - - Le 14 and labyrinth Shi Le 21 Labyrinth sheet - is arranged between the Le 18 - Le 17 and labyrinth sheet. These dry gas seals have a known structure including a rotating ring and a stationary ring, and the rotating ring is fixed to the shaft 11 and the stationary ring is fixed to the casing. On the surface facing the stationary ring of the rotary ring is has a shallow spiral groove, gas enters between the rings,
And he counter selfish guide beauty to groove center is between compressed, which gas pressure increased by shea between the rings - and is adapted to maintain the annular gap.

[0014] In the shaft sealing device according to the invention, the labyrinth sheet - le 15 and labyrinth sheet - room formed between the Le 16 is opened to the atmosphere, the level transmitter 22 is the room and Doraigasushi - and Le 20 An air pipe is connected to a room formed between the labyrinth seal 15 adjacent thereto. The Labyrinth sheet - Labyrinth adjacent to the Le 18 - room formed between the Le 19 is opened to the atmosphere, the level transmitter 23 is the room and Doraigasushi - Labyrinth sheet adjacent thereto and Le 21 - It is connected to the room formed between the base 18 and the base 18 by air piping.

The level transmitter 22 includes a dry gas seal 20 and a labyrinth seal 15 adjacent to the dry gas seal 20.
Room located between the pressure and labyrinth sheet - le 15 and the labyrinth sheet - measures the difference between the pressure room located between the Le 16, and outputs a signal related to the measured differential pressure. In addition, the level transmitter 23 is a dry gas seal 2
1 and labyrinth sheet adjacent thereto - pressure and labyrinth sheet room is between Le 18 - Le 18 and the labyrinth sheet - measures the difference between the pressure room located between the Le 19, the measured differential pressure Output the relevant signal . These level transmitters 22 and 23 are connected to the receiving gauges 24 and 25 by air pipes , respectively, and the signals from the level transmitters 22 and 23 dry the labyrinth seals 15 and 18 to the dry gas seals 20 and 21, respectively. What
The absolute value of the leak amount is displayed. Furthermore, the level transmitter 22 and 23 are connected respectively by the air pipe to a pressure switch 26, 27. Although not shown, the output of these pressure switches, by an electrical signal line, alarm is automatically connected to means to shut down warning light, or this <br/> centrifugal air compressor of.

In this shaft seal device, when the shaft 11 is rotated, carbon dioxide gas is compressed by the impeller 10. At this time, the gas compressed by the impeller leaks from the dry gas seals 20 and 21, and the labyrinth seal is released.
It flows out to Le 15, 18. Level transmitter 22 is labyrinth sheet - bearing 12 on the side rooms and Doraigasushi of Le 15 - the pressure difference between the room on the side of the Le 20, level transmitters 23 Labyrinth sheet - Bear <br/> ring le 18 13 of the side rooms and Doraigasushi - the pressure difference between the room on the side of the Le 21 were measured, these levels Tran limiter outputs a signal related to is come large differential pressure. The receiving gauges 24 and 25 display the differential pressure measured by the level transmitters 22 and 23, for example, as numerical values according to the pneumatic signals output from the level transmitters 22 and 23. The pressure switch 26 and 27, level trans-mission-data 22, 24, 32
It exceeds the value of the air pressure signal is preset from 3, more specifically, Doraigasushi - Gasuri acceptable Le 20, 21 - working to reach the value set in relation to click amount , Activate alarms and warning lights.

In this shaft seal device, the room between the labyrinth seals 15 and 16 and the labyrinth seal 1
Since the room between 8 and 19 is open to the atmosphere as described above and can be regarded as almost atmospheric pressure, the level transmitters 22 and 23 are connected to the labyrinth seals 15 and 18 from the dry gas seals 20 and 21 in operation. The pressure of the leaking gas is to be measured, and the receiving gauges 24 and 25 indicate the pressure of the leaking gas. Dry gas seal 2
0,21 KARARI - actual amount of gas G to click, these levels transmitters 22, 23 and Residencial - bar gate - di 2
It is obtained by converting from the differential pressure ΔP measured by 4 and 25 by the following formula.

[0018]

[Equation 1]

Further, in this shaft sealing device, the shaft 11
Room bearing 12, 13 for supporting is accommodated to the Oiruriza by oil discharge header tube 28 - is connected to the bus 29, Oiruriza lubricating oil of the bearing chamber I through the oil discharge header pipe 28 - flows to the server 29 It has become so. And
An exhaust blower 30 is connected to the vent port of the oil reservoir 29. Exhaust blower 30, oil reservoir - Bas 29,
From the room that holds the oil drain mother pipe 28 and the bearings 12 and 13, that is, the bearing chamber is maintained at a negative pressure and is open to the atmosphere between the labyrinth seal 15 and the labyrinth seal 16. Air flow through the bearing chamber, oil drain mother pipe 28 and reservoir 29, and labyrinth sheet
Bearing chamber from the room which is open to the atmosphere located between the Le 19, oil discharge header pipe 28 and the oil reservoir - the bus 29
Flow of air through the respectively is generated, the mist of the lubricating oil or lubricating oil in the bearing chamber Doraigasushi by this air flow - is prevented from entering the Le 20,21. explain in detail.

[0020] This type of shaft sealing apparatus, if in operation, Doraigasushi - by Kugasu, from the bearing chamber Doraigasushi - - Le or Lawah Zukaniri - click to Li of lubricating oil or lubricating mist to Le intrusion Can be prevented. However, when you stop driving,
Because missing internal gas pressure, Doraigasushi - Le of Li - click flow naturally also eliminated. Bearing chamber, if after shutdown
Barak lubricating oil suspended in the mist is continued Iteori, the lubricating oil mist considerable time has not elapsed with the vanishing pictorial, such as by diffusion effects or capillary action, Doraigasushi from the bearing chamber - countercurrent selfish invade Le. Lubricant Doraigasushi - le of sheet - and enters Le plane, because that would have a stationary ring and the rotating ring should a touch non-close originally contacted by intervening oil film, Li - amount clause or increases, Causing imbalance,
Not only the vibration becomes excessive, the rotational speed of the rotating ring fried high though because <br/> pole, lubricant sheet - seizing Le plane, sheet - may damage the Le itself.

[0021] In the shaft seal apparatus according to the present invention, after the <br/> stop operation, or even during, and after the shutdown operation Bro
A) 30 is operated to make the bearing chamber negative pressure. Room between Labyrinth Seal 15 and Labyrinth Seal 16 and Labyrinth Seal 18 and Labyrinth Seal 1
Since the room between 9 and 9 is open to the atmosphere as described above, the atmosphere is sucked into the bearing chamber from this room, and is sucked by the blower 30 via the oil discharge mother pipe 28 and the oil reservoir 29. Will be issued. At the same time, the lubricating oil or mist of lubricating oil in the bearing chamber is sucked out of the bearing chamber together with this air flow. For this reason, the dry gas seal 20 of the lubricating oil or the lubricating oil mist in the bearing chamber,
Entering the 21 is prevented, Doraigasushi - it is possible to improve the reliability of the Le.

[0022]

According to the present invention, since the actual amount of gas leaked from the dry gas seal can be measured,
Doraigasushi - withered line preventive maintenance Le, reliable axial
A sealing device is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a shaft sealing device of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an example of a conventional shaft sealing device.

[Explanation of Codes] 11 ... Shaft, 12, 13 ... Bearings, 14-1
6, 17 to 19 ... Labyrinth seal, 20, 21 ... Dry gas seal, 22, 23 ... First means, 24, 25 ...
Second means.

Claims (6)

(57) [Claims] 1. A rotatable shaft and a support for the shaft.
The bearing to hold and the bearing of the shaft
Labyrinth seal and drier installed adjacent to the inside
In the shaft sealing device, wherein the bearing side of the labyrinth seal is open to the atmosphere, the pressure on the dry gas seal side of the labyrinth seal is provided.
And a first means for generating a signal based on the difference between the pressure on the bearing side and a means for displaying the amount of leakage from the dry gas seal to the labyrinth seal based on the signal generated by the first means. A shaft sealing device characterized in that it is provided with a second means. 2. A rotatable shaft and a support for the shaft.
The bearing to hold and the bearing of the shaft
Labyrinth seal and drier installed adjacent to the inside
In the shaft sealing device, wherein the bearing side of the labyrinth seal is open to the atmosphere, the pressure on the dry gas seal side of the labyrinth seal is provided.
And a first means for generating a signal based on the difference between the pressure on the bearing side and a means for displaying the amount of leakage from the dry gas seal to the labyrinth seal based on the signal generated by the first means. and second means, the leakage amount is shaft seal device characterized by comprising a third means for generating a warning signal exceeds a predetermined value. 3. The level transmitter said first means outputs an air pressure signal, said second means receiver gauge, said third means comprises respective pressure switch
And it has a shaft sealing apparatus according to claim 2. 4. A warning signal generated by the third means.
The shaft sealing device according to claim 3, further comprising a fourth means that operates in accordance with the above. 5. When the rotation of the shaft is stopped,
Shaft sealing apparatus according to claim 1, wherein the bearing chamber is provided a fifth means for negative pressure that houses the bearing. 6. A drive for discharging lubricating oil from the bearing
A rain piping system is provided in the shaft sealing device, and the fifth means is
The shaft sealing device according to claim 5, which is an exhaust blower provided in the drain piping system .