JP3517710B2 - Shaft sealing device for liquefied gas - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied gas shaft sealing device which is suitable for use in rotary equipment such as a vertical pump that handles liquefied gas such as liquefied ethylene.

[0002]

2. Description of the Related Art In general, a liquefied gas shaft seal device of this type is provided with a seal case surrounding a rotary shaft portion projecting to the outside of a main body casing of a rotary machine.
A shaft seal means composed of a mechanical seal is arranged in the seal case, and a single seal, a double seal or a tandem double seal is adopted as the shaft seal means. In the double or tandem double seal, generally, seal oil (antifreeze oil or the like) having a pressure higher than the internal pressure (liquefied gas pressure) is sealed between the mechanical seals.

[0003]

However, when the shaft sealing means is a single seal, frictional heat generated between the sealing end faces causes the liquefied gas to evaporate (vaporize) between the sealing end faces, and the sealing end faces The contact becomes unstable and the good sealing function is not exhibited. Also, in the double or tandem double seal, since the seal oil with a pressure higher than the internal pressure of the machine is sealed between the mechanical seals, the above problems do not occur, but if the mechanical seal inside the machine reduces the sealing function, the seal oil will be removed. There is a risk of leaking inward and mixing with the liquefied gas that is the fluid inside the machine, and adversely affecting the liquefied gas. Such a problem is particularly remarkable in a rotating device that handles a cryogenic liquefied gas such as liquefied ethylene.

An object of the present invention is to provide a liquefied gas shaft sealing device which can perform a shaft sealing function in a rotating device handling liquefied gas in a good and stable state without causing such a problem. To do.

[0005]

A liquefied gas shaft sealing device according to the present invention, which has solved this problem, has a main body casing of a rotary device that handles liquefied gas, and a seal case surrounding a rotary shaft portion projecting to the outside. A shaft sealing means composed of a mechanical seal is provided in the seal case, and a space between the shaft sealing means and the main body casing in the seal case is rotated by a partition wall through which the rotary shaft penetrates. It is characterized by being partitioned into a plurality of seal chambers arranged in parallel in the axial direction of the shaft. When the rotating device is a vertical pump, the seal case is
It is provided so as to surround the rotating shaft portion that penetrates through and projects upward. The shaft sealing means arranges the first and second mechanical seals, which are non-contact type mechanical seals, in parallel in the axial direction of the rotary shaft, and liquefies the liquid inside the machine in a purge chamber formed between the mechanical seals. It is preferable to supply the purge gas at a pressure lower than the gas pressure. Further, a communication passage that passes outside the seal case is provided between the seal chamber adjacent to the shaft sealing means and the seal chamber adjacent thereto, and heat exchange for vaporizing the liquefied gas in the communication passage portion outside the seal case. It is preferable to provide a heater or a heater.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
4 will be described. In the following explanation,
The upper and lower sides mean the upper and lower sides in FIGS.

This embodiment relates to an example in which the present invention is applied to a shaft seal device for a vertical pump that handles cryogenic liquefied gas such as liquefied ethylene. That is, as shown in FIG. 1, the liquefied gas shaft sealing device 1 according to the present invention in this embodiment includes a main body casing (pump casing) 2 of a vertical pump,
A seal case 4 surrounding the rotary shaft portion 3a penetrating therethrough and protruding upward is provided, and in the seal case 4, a shaft sealing means 5 constituted by a mechanical seal is arranged and a plurality of seal chambers 6 ... It will be provided. The rotary shaft 3 of the vertical pump is an impeller shaft that is suspended from a prime mover (not shown) supported above the main body casing 2 into the main body casing 2 (pump chamber), and an impeller 7 is provided at the lower end portion. It is installed.

As shown in FIG. 2, the seal case 4 has a cylindrical shape that concentrically surrounds the upper end portion 3a of the rotary shaft 3 protruding from the main body casing 2, and is attached to the upper surface of the main body casing 2. ing.

As shown in FIG. 1, the shaft sealing means 5 includes an upper end portion of the seal case 4 and a rotary shaft 3 which concentrically penetrates the upper end portion.
The first and second mechanical seals 8 and 9 which are non-contact type mechanical seals are arranged in parallel in the axial direction (vertical direction) of the rotary shaft 3 between the opposing peripheral surface portions of the tandem seal structure. A purge gas control mechanism 12 for supplying and controlling a purge gas 11 to a purge chamber 10 formed between both mechanical seals 8 and 9 is provided. The first mechanical seal 8 is arranged on the main body casing 2 side and is located below the second mechanical seal 9.

The seal chambers 6 ... Are provided in a region below the shaft sealing means 5 in the seal case 4. That is,
Two or more sealing chambers arranged in parallel in the vertical direction by one or more partition walls 13 through which the rotating shaft 3 penetrates a region between the shaft sealing means 5 and the main body casing 2 in the seal case 4. It is divided into 6 ... In this example, as shown in FIGS. 1 and 2, in this example, three seal chambers are provided by the first and second partition walls 13a and 13b that are provided in parallel in the seal case 4 at predetermined intervals in the vertical direction. It is divided into 6 ... In the following description, the "first seal chamber 6a", the "second seal chamber 6b", and the "third seal chamber 6a" are sequentially arranged from the highest order.
The seal chamber 6c ". The first seal chamber 6a is formed between the lower first mechanical seal 8 and the first partition wall 13a, and the second seal chamber 6b is formed between both partition walls 13a and 13b. , The third
The seal chamber 6c is formed between the second partition wall 13b and the main body casing 2 (more accurately, between the second partition wall 13b and the bottom wall 4a of the seal case 4 attached to the main body casing 2). It is a thing. Further, the seal chamber 6 ... The partition walls 13a, 13b between the seal chamber 6 and the inside of the main body casing 2 and the seal chamber 6 adjacent thereto (third lowest seal chamber 6c)
A partition wall (which is the bottom wall 4a of the main body casing 2 or the seal case 4, which corresponds to the latter bottom wall 4a in this example) is provided with a through hole through which the rotary shaft 3 passes.
The annular gap 14 between each through hole and the rotary shaft 3 is minute so as to prevent the fluid from entering through the annular gap 14 as much as possible. In this example, the partition walls 4a, 13a, 13
By providing a simple seal member (a bush seal is used in the illustrated example) 15 such as a bush seal or a labyrinth seal in the through hole of b, the rotary shaft 3 forms a minute annular gap 14 in each partition wall. It is devised so that it has a through hole. The constituent materials of the seal case 4 including the partition wall and each seal member 15 are selected according to the property of the liquefied gas, and in this example, a metal material having excellent low temperature resistance is used.

By providing such a seal chamber 6 between the main body casing 2 and the shaft sealing means 5 (first mechanical seal 8), the liquefied gas (in-machine liquid) 16 in the main body casing 2 is sealed. When it has entered the case 4, the in-machine liquid 16 that has entered the case 4 or the second seal chamber 6c
In the region below the shaft sealing means 5 in the seal case 4 after being vaporized (vaporized) in the seal chamber 6b, the pressure of the in-machine liquid 16 and the pressure of the vaporized gas (ethylene gas or the like) 16a are balanced. The liquid phase is maintained, and at least the uppermost first seal chamber 6a is maintained in the gas phase where no liquid phase exists. That is, the first seal chamber 6a is filled with the evaporative gas 16a. Each seal room 6
And the number of installed seal chambers 6 are set according to the pressure and properties of the in-machine liquid 16 so that the in-machine liquid 16 is filled with the evaporative gas 16a at least in the first seal chamber 6a. It

In addition, at least a seal chamber (first mechanical seal 8 to be more precise) adjacent to the shaft sealing means 5 (first mechanical seal 8)
In order to reliably maintain the seal chamber 6a in the vapor phase state as described above, it is preferable to provide a means for actively evaporating the in-machine liquid 16 in the seal chambers 6 other than the seal chamber 6a. In this example, as the positive evaporation means, as shown in FIGS. 1 and 2, a first seal chamber 6a adjacent to the shaft sealing means 5 and a second seal chamber 6b adjacent to the first seal chamber 6a.
A communication passage 17 passing outside the seal case 4 is provided between the heat exchanger 19 and a dry gas (dry air, etc.) 18 having a temperature higher than that of the in-machine liquid 16 and introduced into the communication passage outside the seal case 4. Even if the in-machine liquid 16 enters the second seal chamber 6b from the third seal chamber 6c, the in-machine liquid 16 is introduced from the second seal chamber 6b to the heat exchanger 19 and dried. It is evaporated (vaporized) by heat exchange with the gas 18, and the evaporated gas 16a is connected to the communication passage 17
Is designed to be supplied to the first seal chamber 6a. That is, the liquid level of the in-machine liquid 16 is the second seal chamber 6b.
Does not rise beyond the opening position of the communication passage 17 (the opening position of the in-machine liquid overflow port 17b) and at least the first seal chamber 6a is filled with the evaporating gas 16a. The temperature of the dry gas 18 is arbitrarily set according to the property of the in-machine liquid 16 (particularly the liquid temperature), but in this example, the temperature is set to a temperature at which the evaporative gas 16a at a normal temperature can be generated. The communication passage 17 is provided in the seal case 4, and has an evaporative gas supply port 17a opening at an upper end portion of the first seal chamber 6a and an in-machine liquid overflow port 17b opening at appropriate places in the second seal chamber 6b, and an in-machine liquid. In-machine liquid introduction path 1 from the overflow port 17b to the heat exchanger 19 arranged outside the seal case 4
7c and an evaporative gas supply path 17d from the heat exchanger 19 to the evaporative gas supply port 17a. In-machine liquid introduction path 17c
The heat exchanger 19 is arranged at the same height as the in-machine liquid overflow port 17b or at a position lower than this.

As shown in FIG. 3, each of the mechanical seals 8 and 9 has a rotary seal ring 21 fixed to the rotary shaft 3 and a static seal ring 22 directly opposed to the rotary seal ring 21 above the seal case 4. Is movably held in the axial direction via a holding ring 23, and a static sealing ring 22 is pressed and urged toward the rotary sealing ring 21 by a spring 24 interposed between the seal case 4 and the holding ring 23. , One of the sealing end faces 25, 26 which is an opposing end face of the two sealing rings 21, 22 (in this example, the sealing end face 25 of the rotary sealing ring 21), is disposed between the sealing end faces 25, 26 with the relative rotation of the sealing rings 21, 22. Dynamic pressure generating groove 2 for generating dynamic pressure by the fluid in the outer diameter side region of the relative rotation portion
7, the sealing end surfaces 25 and 26 rotate relative to each other while being held in a non-contact state by the above dynamic pressure, so that the outer diameter side region of the relative rotation portion (the first mechanical seal 8 is That is the first seal chamber 6a, and the second mechanical seal 9 is the purge chamber 10).
And its inner diameter side region (the purge chamber 10 in the first mechanical seal 8 and the upper region (atmosphere region) 28 of the seal case 4 in the second mechanical seal)
It is a dynamic pressure type gas seal (a non-contact type mechanical seal) configured to seal a gap between and. That is,
The sealing end surfaces 25 and 26 are held in a non-contact state having a minute gap by balancing the opening force acting in the opening direction between them and the closing force acting in the closing direction.
Here, the opening force is due to the dynamic pressure generated between the sealed end faces 25 and 26, and the closing force is the spring pressure (spring 2
4) and back pressure acting on the stationary seal ring 22 in the direction of pressing it against the rotary seal ring 21 (in the case of the first mechanical seal 8, the back surface (upper surface) of the stationary seal ring 22).
The pressure of the evaporative gas 16a acting on the second mechanical seal 9 is the rear surface (upper surface) of the stationary seal ring 22.
(Which is the pressure of the purge gas 11 that acts on).

The stationary seal ring 22 is formed by the seal case 4
In addition, it is internally fitted and held so as to be movable in the axial direction with a very small gap therebetween (for example, with a dimensional tolerance of clearance fit in JIS-B0401). Further, as shown in FIG. 3, drive pins 29 and 30 allow relative rotation between the stationary seal ring 22 and the holding ring 23 and between the seal case 4 and the holding ring 23 while allowing relative movement in the axial direction. Impossiblely linked. Further, the stationary seal rings 22 and 23 are held in a non-contact state in which they are sealed (secondary seal) by an O-ring 31. The O-ring 3 is provided between the seal case 4 and the retaining ring 23.
2, the retaining ring 23 is sealed (secondary seal) in a state in which it is allowed to move in the axial direction. Also, each sealing ring 2
1, 22 are made of a super-hard material such as WC or SiC or a steel material having a hard layer such as titanium nitride formed on the surface (sealing end surface) according to the sealing condition, and the retaining ring 23 is made of SUS3.
It is made of a metal material such as 04 or Ti.

The purge gas control mechanism 12 is provided in the seal case 4 as shown in FIGS.
A purge gas supply port 34 and a purge gas discharge port 35 that are open to the air, a purge gas supply route 36 that is connected to the purge gas supply port 34, and a purge gas discharge route that is connected to the purge gas discharge port 35 and is guided to a flare (not shown). 37,
An orifice 38 arranged in the purge gas discharge path 37,
A bypass 39 connected between an upstream side portion and a downstream side portion of the orifice 38 in the purge gas discharge passage 37,
The bypass valve 39 includes a solenoid valve 40 and a pressure switch 41, and a pressure gauge 42 disposed upstream of the purge gas discharge path 37. According to the purge gas control mechanism 12, the purge gas 11 having a pressure lower than the pressure of the liquid 16 in the machine, that is, the pressure of the filling gas (evaporated gas) 16a in the first seal chamber 6a in a pressure equilibrium state with the purge gas is supplied from the purge gas supply passage 36. 10 and supplies the purge gas 11 with the sealed end surfaces 25, 2 of the first mechanical seal 8.
Along with the evaporative gas 16a leaking into the purge chamber 10 from between 6, the purge gas is discharged from the purge gas discharge path 37 to the flare. The pressure of the purge chamber 10 is maintained at a predetermined pressure lower than the pressure of the first seal chamber 6a by the orifice 38, but the leak amount of the evaporative gas 16a from the first seal chamber 6a increases and the pressure of the purge chamber 10 increases. When the pressure rises and reaches the upper limit set pressure, the pressure switch 41 is turned on, an alarm is issued, the solenoid valve 40 is opened, and the leakage gas (evaporated gas 16
The purge gas 11 containing a) is discharged to the flare from the bypass 39, and prevents the pressure in the purge chamber 10 from rising. When the pressure in the purge chamber 10 falls and reaches the lower limit set pressure due to the purge gas discharged from the bypass 39, the pressure switch 41 is turned off, the electromagnetic valve 40 is closed, and the purge gas discharge from the bypass 39 is stopped. By opening and closing the solenoid valve 40 with such a pressure switch 41, the purge chamber 10
Is maintained at a pressure lower than the first seal chamber 6a by a predetermined pressure.
As the purge gas 11, a dry gas inert to the in-machine liquid 16 or its evaporated gas 16a is used.
In this example, nitrogen gas at room temperature is used. In addition, in this example, the quench passage 43 branched from the purge gas supply passage 36 is provided in an upper region (atmosphere region) of the seal case 4.
It is devised so that the second mechanical seal 9 is quenched with nitrogen gas at room temperature, which is the purge gas 11, by guiding the second mechanical seal 9 to a portion in the vicinity of the second mechanical seal 9.

According to the liquefied gas shaft sealing device 1 configured as described above, the shaft can be satisfactorily and stably sealed in the vertical pump that handles the cryogenic liquefied gas 16 such as liquefied ethylene.

That is, the in-machine liquid 16 that has entered the third seal chamber 6c from the penetrating portion of the rotary shaft 3 in the main body casing 2 is in the third seal chamber 6c or in the second seal chamber 6c.
In the region below the shaft sealing means 5, the pressure of the in-machine liquid 16 and the pressure of the vaporized gas 16a thereof are kept in a gas-liquid two-phase state in which the pressure is balanced, and at least the first uppermost layer is evaporated. The seal chamber 6a is filled with the evaporative gas 16a. That is, the rise of the liquid level of the in-machine liquid 16 in the seal case 4 is stopped when the pressure of the evaporative gas 16a is balanced, and the volume of each seal chamber 6 and the number of installed seal chambers 6 ... The in-machine liquid 16 does not enter the first seal chamber 6 by appropriately setting it according to the properties and the like. In the case where the evaporation in the third seal chamber 6c or the second seal chamber 6b is not sufficiently performed and the liquid level of the in-machine liquid 16 rises to the first seal chamber 16a, the second seal chamber 6c In-flight liquid 16 that entered 6b
Is overflowed and discharged from the communication passage 17 to the heat exchanger 19, and the in-machine liquid 16 is evaporated by heat exchange with the dry gas 18 in the heat exchanger 19, and the vaporized gas 16a is discharged from the communication passage 17 into the first seal. It is supplied to the chamber 6a. Therefore,
The liquid level of the in-machine liquid 16 does not rise beyond the opening portion (in-machine liquid overflow port) 17b of the communication passage 17 in the second seal chamber 6b, and the in-machine liquid 16 does not enter the first seal chamber 6a. Certainly blocked.

Thus, the first seal chamber 6a thus filled with the evaporative gas 16a is sealed by the shaft sealing means 5, and the leakage of the in-machine liquid 16 to the outside of the machine is reliably prevented.

That is, the first seal chamber 6a and the purge chamber 1
In the first mechanical seal 8 that seals between the sealed end surfaces 25 and 2 of the first seal chamber 6a, the vaporized gas 16a that fills the first seal chamber 6a is introduced into the dynamic pressure generation groove 27.
By balancing the opening force due to the dynamic pressure generated between 6 and the closing force due to the spring pressure and the pressure (back pressure) of the vaporized gas 16a acting on the back surface of the stationary seal ring 22,
The sealed end faces 25, 26 are held in a non-contact state. Since the opening force and the closing force for holding the sealed end faces 25 and 26 in the non-contact state are due to the evaporative gas 16a and the spring pressure as described above, the pressure fluctuations in the first seal chamber 6a or the purge chamber 10 are caused. Even if it occurs, the balance between the opening force and the closing force does not change, and the sealed end faces 25 and 26 are always kept in a proper non-contact state. Similarly, in the second mechanical seal 9 as well, since the opening force and the closing force acting on the sealed end surfaces 25 and 26 are due to the purge gas 11 and the spring pressure, the pressure in the purge chamber 10 is the first mechanical seal 8.
Even if the sealed end faces 25 and 26 change due to leakage of evaporative gas from the sealed end faces 25 and 26, the sealed end faces 25 and 26 are held in a proper non-contact state. Therefore, the shaft sealing function of both mechanical seals 8 and 9 is performed satisfactorily and stably, and the leakage of the in-machine liquid 16 is reliably prevented. The evaporative gas 1 in the first seal chamber 6a
A small amount of 6a leaks from the first mechanical seal 8, which is a non-contact type mechanical seal, to the purge chamber 10. The leaked evaporative gas 16a is discharged to the flare together with the purge gas 11 from the purge gas discharge passage 37.

Further, since the pressure of the purge chamber 10 is lower than that of the liquid 16 in the machine or the evaporative gas 16a, the purge gas 11 is the first mechanical seal 8 even though the first mechanical seal 8 is a non-contact type mechanical seal. There is no risk that the in-machine liquid 16 will be adversely affected by the contact and mixing with the purge gas 11 without leaking to the seal chamber 6a.
Even if the sealing function of the first mechanical seal 8 deteriorates for some reason, the purge gas 11 does not leak to the first seal chamber 6a, and the above-mentioned fear does not occur. Further, even when a large amount of the evaporated gas 16a leaks into the purge chamber 10 due to the deterioration of the sealing function of the first mechanical seal 8, the purge gas control mechanism 12 prevents a large pressure fluctuation in the purge chamber 10 as described above. Therefore, the purge chamber 11 does not become higher in pressure than the first seal chamber 6a and the purge gas 11 does not leak to the first seal chamber 6a in a large amount.

Even when the in-machine liquid 16 is a cryogenic liquefied gas and the evaporative gas 16a filling the first seal chamber 6a is a low temperature gas, the purge chamber 10 between the mechanical seals 8 and 9 is dried at room temperature. Since the purge gas 11 that is a gas (nitrogen gas) is supplied and the quench gas having the same property as the purge gas 11 is supplied from the quench passage 43 to the vicinity of the second mechanical seal 9 in the atmosphere region 28, the shaft sealing means The occurrence of the icing phenomenon in 5 or its peripheral region is reliably prevented, and the shaft-sealing function of the shaft-sealing means 5 is excellent and stable. This anti-icing action is
Evaporative gas 16a at around room temperature is generated in the heat exchanger 19 and is supplied to the first seal chamber 6a in the vicinity of the first mechanical seal 8 from the communication passage 17, so that it is performed more effectively.

The present invention is not limited to the above-mentioned embodiments, but can be appropriately improved or modified within the range not departing from the basic principle of the present invention.

For example, the heat exchanger 19 provided in the communication passage 17
When the in-machine liquid 16 is a cryogenic liquefied gas such as ethylene gas, a part of the communication passage 17 is placed in the atmosphere region outside the seal case 4 and introduced into the communication passage 17 by heat exchange with the atmosphere. It may be configured to evaporate the in-machine liquid 16 thus generated. In this case, it is preferable to provide a heat transfer part such as a fin for improving the efficiency of heat exchange with the atmosphere in the communication passage portion arranged in the atmosphere region. Further, instead of the heat exchanger 19, a heater (heater) that positively heats the in-machine liquid 16 may be used.

The number of the sealing chambers 6 ... Installed in the sealing chamber 6 adjacent to the shaft sealing means 5 is the vaporized gas 16a of the liquid 16 in the machine.
Can be appropriately set according to the volume of each seal chamber 6 and the pressure and properties of the liquid 16 in the machine, provided that a communication passage 17 having a heat exchanger 19 or a heater is provided. By setting it, it is possible to reduce the number as much as possible (for example, not providing the third seal chamber 6c in the above example).

The mechanical seal constituting the shaft sealing means 5 is not limited to the tandem double gas seals 8 and 9 described above, and any single, double or tandem type can be used as long as it can seal the vaporized gas 16a. Double end face contact or non-contact mechanical seals can be used. For example, an end face contact type mechanical seal that exerts a sealing function by two rotary end faces facing each other sliding relative to each other, or a static seal that holds two opposing end faces in a non-contact state by supplying a seal gas therebetween. It is also possible to use a single pressure type gas seal (non-contact mechanical seal).

Further, the present invention is applicable to a shaft sealing device for any type of rotary equipment other than the above-mentioned pump, such as vertical rotary equipment, horizontal rotary equipment, rotary equipment handling liquefied gas at room temperature, etc. be able to. Further, when the present invention is applied to a rotary device that handles a liquefied gas at a temperature (normal temperature or the like) at which there is no risk of the icing phenomenon, it is not necessary to use a dry gas as the purge gas 11 or the like.

[0027]

As is apparent from the above description, according to the present invention, it is possible to exert a stable and good shaft-sealing function by a mechanical seal in various rotary devices that handle liquefied gas. You can drive safely.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view showing a vertical pump equipped with a liquefied gas shaft sealing device according to the present invention.

FIG. 2 is a detailed view showing an enlarged main part of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a front view showing a main part of a sealed end surface.

[Explanation of Codes] 1 ... Shaft sealing device for liquefied gas, 2 ... Main body casing, 3 ... Rotating shaft, 3a ... Rotating shaft portion protruding from main body casing,
4 ... Seal case, 4a ... Bottom wall of seal case, 5 ... Shaft sealing means, 6a ... First seal chamber (seal chamber adjacent to shaft sealing means), 6b ... Second seal chamber, 6c ... Seal chamber, 8 ... 1st mechanical seal, 9 ... 2nd mechanical seal, 10 ... Purge chamber, 11 ... Purge gas, 12 ... Purge gas control mechanism, 13a, 13b ... Partition wall, 16 ... In-machine gas (liquefied gas), 16a ... Evaporated gas, 17 ... Communication passage, 1
9 ... Heat exchanger.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-166766 (JP, A) JP-A-49-37047 (JP, A) Fukukaihei 3-130968 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) F16J 15/34 F04D 7/02 F04D 29/12

Claims (4)

(57) [Claims] 1. A main body casing of a rotary device that handles liquefied gas is provided with a seal case surrounding a rotary shaft portion protruding to the outside thereof, and a shaft sealing means constituted by a mechanical seal is provided in the seal case. and the space between the shaft sealing means and the body casing in the seal case, the partition wall rotary shaft passes, a plurality of liquefied gas shaft that is partitioned into the seal chamber in parallel to the axial direction of the rotary shaft Sealing device
And the shaft sealing means is a non-contact type mechanical seal.
The second mechanical seal is arranged in parallel in the axial direction of the rotating shaft.
And a purge chamber formed between both mechanical seals
In addition, the purge gas at a pressure lower than the pressure of the liquefied gas that is the liquid inside the machine
A liquefied gas shaft sealing device, characterized in that it is configured to supply . 2. A main body casing of a rotating device that handles liquefied gas
The seal surrounding the rotating shaft that projects to the outside.
A mechanical case inside the seal case.
In this seal case
The space between the shaft sealing means and the body casing in
Partition walls through which the rolling shaft penetrates allow for parallelization in the axial direction of the rotating shaft.
Shaft sealing device for liquefied gas divided into multiple sealing chambers
And a seal chamber adjacent to the shaft sealing means and a seal chamber adjacent to the seal chamber
If a communication passage that passes outside the seal case is provided between
In addition, the liquefied gas is evaporated in the communication passage outside the seal case.
Characterized by arranging a heat exchanger or heater for
A shaft sealing device for liquefied gas. 3. A shaft sealing means arranges first and second mechanical seals, which are non-contact type mechanical seals, in parallel in an axial direction of a rotary shaft, and a liquid inside the machine is placed in a purge chamber formed between the mechanical seals. characterized in that it is configured to provide a low pressure purge gas from the pressure of the liquefied gas is, shaft sealing instrumentation for liquefied gas according to claim 2
Place 4. The rotating device is a vertical pump,
A rotation that penetrates the top surface of the thing and projects upwards.
The shaft sealing device for liquefied gas according to claim 1, wherein a seal case surrounding the shaft portion is provided .