KR970010869B1

KR970010869B1 - Sealing of shaft

Info

Publication number: KR970010869B1
Application number: KR1019930015781A
Authority: KR
Inventors: 히로후미 아리쯔보; 토시히코 후세
Original assignee: 닛뽄필러코오교오 가부시키가이샤; 이와나미 키요히사
Priority date: 1993-08-14
Filing date: 1993-08-14
Publication date: 1997-07-01
Also published as: KR950006285A

Abstract

내용없음No content

Description

Shaft

제1도는 본 발명에 의한 축봉장치의 제1실시예를 표시하는 반단면도.1 is a half cross-sectional view showing a first embodiment of the shaft device according to the present invention.

제2도는 본 발명의 제2실시예를 표시하는 개략적인 반단면도.2 is a schematic half sectional view showing a second embodiment of the present invention.

제3도는 본 발명의 제3실시예를 표시하는 개략적인 반단면도.3 is a schematic half sectional view showing a third embodiment of the present invention.

제4도는 본 발명의 제4실시예를 표시하는 개략적인 반단면도.4 is a schematic half sectional view showing a fourth embodiment of the present invention.

제5도는 종래 장치를 표시하는 반단면도.5 is a half sectional view showing a conventional device.

본 발명은 각종 펌프 등의 유체기계에 장비되는 축봉(軸封)장치에 관한 것으로, 특히 시일케이싱 및 그것을 관통하는 회전축의 한쪽에 제1밀봉환(密封環)을 고정, 지지함과 아울러, 다른쪽에 제1밀봉환에 대해 눌러서 밀어주는 제2밀봉환을 축선방향으로의 미끄럼작동이 가능하도록 지지하여 이루어지는 2조(組)의 메커니컬시일(mechanical seal)에 의해, 양쪽의 메커니컬시일 사이에 형성된 퍼어지유체영역을 개재하여 피밀봉유체영역과 대기영역을 차폐, 밀봉하도록 구성된 축봉장치에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a shaft rod device that is equipped with a fluid machine such as various pumps. The fur formed between both mechanical seals by two sets of mechanical seals formed by supporting the second sealing ring pressed against the first sealing ring on the side so as to enable sliding in the axial direction. The present invention relates to a shaft device configured to shield and seal a hermetically sealed fluid region and an atmospheric region via a selvage fluid region.

종래의 이와 같은 종류의 축봉장치로서는 제5도에 표시하듯이, 2조의 접촉형 메커니컬시일(1a,1b)을 반대방향으로 배치한 소위 이중밀봉이 잘 알려져 있다.As a conventional rod device of this kind, a so-called double seal in which two sets of contact type mechanical seals 1a and 1b are arranged in opposite directions is well known, as shown in FIG.

즉, 양쪽의 메커니컬시일(1a,1b)은, 각각 시일케이싱(5)에 정지밀봉환(2a,2b)을 고정지지시킴과 아울러, 회전축(6)에, 정지밀봉환(2a,2b)에 힘을 가하여 밀어주는 회전밀봉환(3a,3b)을 축선방향을 따라 미끄럼이동이 가능하도록 지지하여 구성되며, 이들 밀봉환(2a,3a 및 2b,3b)의 상대회전 미끄럼접촉작용에 의하여 적당한 압력(이하의 설명에 있어서, 압력이라고 할 때에는 대기압을 기준으로 한 게이지압력을 의미한다)의 퍼어지액(물, 기름 등)(L)을 주입한 퍼어지유체영역(C)을 개재하여, 피밀봉유체영역(A)과 대기영역(B)을 차폐, 밀봉하도록 구성되어 있다.That is, both mechanical seals 1a and 1b hold the stationary sealing rings 2a and 2b to the seal casing 5, respectively, and to the rotary shaft 6 to the stationary sealing rings 2a and 2b. It is configured to support the sliding sealing ring (3a, 3b) for pushing by applying a force to the sliding movement along the axial direction, the appropriate pressure by the relative rotation sliding contact action of these sealing rings (2a, 3a and 2b, 3b) (In the following description, the pressure means the gauge pressure on the basis of atmospheric pressure.), And through the purge fluid region C into which the purge liquid (water, oil, etc.) L is injected, It is comprised so that the sealing fluid area | region A and the air | atmosphere area B may be shielded and sealed.

그러므로, 이러한 종래의 장치에 있어서는, 회전밀봉환(3a,3b)에 퍼어지유체(L)의 압력(P')이 배압(背壓)으로 작용하는 까닭에, 피밀봉체영역(A)측의 메커니컬시일(1a)에 있어서의 양 밀봉환(2a,3a)의 접촉을 적정하게 유지시키기 위해 퍼어지유체압력(P')을 피밀봉유체압력(P)보다도 소정량(△P)높게하고 있다(P'=P+△P). 왜냐하면, 퍼어지유체압력(P')이 피밀봉유체압력(P)보다 낮으면, 양 밀봉환(2a,3a)이 적정한 접촉상태를 유지할 수 없으므로, 스프링(4a)에 의한 눌러서 밀어주는 힘을 필요 이상으로 크게 하지 않으면 안된다고 하는 결점이 발생하기 때문이다.Therefore, in such a conventional apparatus, since the pressure P 'of the purge fluid L acts as a back pressure on the rotational sealing rings 3a and 3b, the side to be sealed is subjected to the area A. The purge fluid pressure P 'is a predetermined amount (ΔP) higher than the sealed fluid pressure P in order to properly maintain the contact between the two sealing rings 2a and 3a in the mechanical seal 1a. (P '= P + ΔP). If the purge fluid pressure P 'is lower than the sealed fluid pressure P, both sealing rings 2a and 3a cannot maintain an appropriate contact state, and thus the pushing force by the spring 4a is applied. This is because a disadvantage arises that it must be made larger than necessary.

그러나, 피밀봉유체영역(A)과 퍼어지유체영역(C) 사이를 밀봉하는 제1메커니컬시일(1a)에 대해서는 상기한 바와 같이 퍼어지유체압력(P')을 피밀봉유체압력(P)보다 높게 해둘 필요가 있으므로, 특히, 피밀봉유체가 액체 암모니아 등의 휘발성 유체 내지 저비등점 유체인 경우에는, 밀봉환(2a,3a) 사이에 형성되는 유체윤활막이 미끄럼작동시 발생되는 열에 의해 파손되기 쉽고, 그것이 원인이 되어 시일이 파손될 우려가 있다. 그리고, 시일이 파손되면 퍼어지액(L)이 피밀봉유체영역(A)측으로 누설된다.However, for the first mechanical seal 1a that seals between the sealed fluid region A and the purge fluid region C, as described above, the purge fluid pressure P 'is defined as the sealed fluid pressure P. Since it is necessary to make it higher, especially when the to-be-sealed fluid is a volatile fluid such as liquid ammonia or a low boiling point fluid, the fluid lubricating film formed between the sealing rings 2a and 3a may be damaged by the heat generated during the sliding operation. It is easy to cause it, and there exists a possibility that a seal may be damaged. When the seal is broken, the purge liquid L leaks to the sealed fluid region A side.

한편, 대기영역(B)과 퍼어지유체영역(C) 사이를 밀봉하는 제2메커니컬시일(1b)에 대해서는, 그것이 접촉형 시일이기 때문에, 양 영역(B,C) 사이의 차압(P+△P)이 극히 크게 되는 고압조건 하에서는 밀봉기능이 손상될 우려가 있다.On the other hand, for the second mechanical seal 1b that seals between the atmospheric zone B and the purge fluid zone C, since it is a contact type seal, the differential pressure P + ΔP between both zones B and C Under high pressure conditions where)) is extremely large, the sealing function may be impaired.

이와 같이, 종래 장치는 전체적으로 신뢰성이 낮아서, 밀봉조건(피밀봉유체의 성상(性狀)이나 압력조건)에 따라서 적당하게 사용할 수 없는 것이다. 또, 퍼어지액(L)을 순환시키기 위한 주변기기가 필요하게 되므로 장치구조가 복잡화되는 문제도 있다.As described above, the conventional apparatus is generally low in reliability and cannot be suitably used in accordance with the sealing conditions (the properties and the pressure conditions of the sealed fluid). In addition, since a peripheral device for circulating the purge liquid L is required, there is a problem that the device structure is complicated.

본 발명의 목적은, 고압조건 하, 또는, 액체 암모니아 등의 휘발성 유체 내지 저비등점 유체에 대해서도 양호하고, 또한 안정된 밀봉기능을 발휘하는, 신뢰성이 높은 축봉장치를 제공함에 있다.SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable storage device that exhibits a good and stable sealing function even under a high pressure condition or a volatile fluid such as liquid ammonia or a low boiling point fluid.

본 발명의 다른 목적은 퍼어지유체를 순환시키기 위한 주변기기를 필요로 하지 않고, 장치의 구조를 간소화 할 수 있는 축봉장치를 제공함에 있다.Another object of the present invention to provide a shaft device that can simplify the structure of the device, without the need for a peripheral device for circulating the purge fluid.

제1도는 본 발명의 축봉장치의 바람직한 실시예를 표시하는 것으로, 이 축봉장치는, 시일케이싱(15)과 그것을 관통하는 회전축(16) 사이에, 회전축(16)의 축선방향으로 병렬배치된 상태에서, 그 사이에 설치된 2조의 메커니컬시일(11,21)에 의해 양 메커니컬시일(11,21) 사이에 형성된 퍼어지유체영역(C)을 개재하여, 피밀봉유체영역(A)과 대기영역(B)을 차폐, 밀봉하도록 구성된 것이다.1 shows a preferred embodiment of the shaft device of the present invention, wherein the shaft device is arranged in parallel in the axial direction of the rotation shaft 16 between the seal casing 15 and the rotation shaft 16 passing therethrough. In the sealed fluid region (A) and the atmosphere region (2) via a purge fluid region (C) formed between the two mechanical seals (11, 21) by two sets of mechanical seals (11, 21) provided therebetween. B) is shielded and sealed.

각 메커니컬시일(11,21)은 회전축(16)에 고정 지지된 회전밀봉환인 제1밀봉환(12,22)과, 시일케이싱(15)에 축선방향으로의 미끄럼작동이 가능하도록 지지된 정지밀봉환인 제2밀봉환(13,23)과, 제2밀봉환(13,23)을 제1밀봉환(12,22)에 대해 눌러서 밀어주는 스프링(14,24)을 구비하여 구성된다.Each mechanical seal (11, 21) is a first sealing ring (12, 22), which is a rotation sealing ring fixedly supported on the rotating shaft 16, and the stationary sealing supported to enable the sliding operation in the axial direction to the seal casing (15) The second sealing ring 13, 23 which is a ring, and the spring 14,24 which presses and pushes the 2nd sealing ring 13,23 with respect to the 1st sealing ring 12,22 are comprised.

그리고, 피밀봉유체영역(A)측의 제1메커니컬시일(11)은 양 밀봉환(12,23)이 피밀봉유체에 의한 유체윤활막을 개재한 접촉상태에서 상대회전하므로써 피밀봉유체영역(A)과 퍼어지유체영역(C)을 밀봉하는 접촉형 시일로 구성되어 있다.The first mechanical seal 11 on the side of the sealed fluid region A has a sealed fluid region A as both sealing rings 12 and 23 rotate relative to each other in a contact state via a fluid lubrication membrane by the sealed fluid. ) And a purge fluid region (C).

한편, 대기영역(B)측의 제2메커니컬시일(21)은 제1밀봉환(22)의 끝면에, 외주측 또는 내주측으로 개구하는 나선형상, T자형상, 직사각형상 등의 동압발생홈(22a)을 형성하여, 양 밀봉환(22,23)을, 그 사이에 발생되는 동압에 의하여 비접촉상태로 상대회전시키므로써, 대기영역(B)과 퍼어지유체영역(C)을 밀봉하는 비접촉형 시일로 구성되어 있다.On the other hand, the second mechanical seal 21 on the side of the standby region B has a dynamic pressure generating groove such as a spiral, T-shape, rectangular shape, and the like, which is opened to the outer circumferential side or the inner circumferential side on the end face of the first sealing ring 22 22a), and the non-contact type sealing the air space B and the purge fluid area C by rotating both sealing rings 22 and 23 in a non-contact state by the dynamic pressure generated therebetween. It consists of a seal.

또, 양쪽의 메커니컬시일(11,21)은 제2밀봉환(13,23)이 제1밀봉환(12,22)보다 대기영역(B)쪽으로 접근한 위치가 되도록 같은 방향으로 배치되어 있고, 제2밀봉환(13,23)에는, 제1메커니컬시일(11)에 있어서는 피밀봉유체영역(A)의 유체압력(P)이, 그리고, 제2메커니컬시일(21)에 있어서는 퍼어지유체영역(C)의 유체압력(P')이 각각 배압으로서 작용하도록 되어 있다.In addition, both mechanical seals 11 and 21 are arranged in the same direction so that the second sealing rings 13 and 23 are closer to the standby area B than the first sealing rings 12 and 22, In the second sealing rings 13 and 23, the fluid pressure P of the sealed fluid region A in the first mechanical seal 11 is, and the purge fluid region in the second mechanical seal 21. The fluid pressure P 'of (C) acts as a back pressure, respectively.

또, 퍼어지유체영역(C)에는, 피밀봉유체압력(P)보다 저압(P')(=P-△P)인 퍼어지가스(G)가 봉입되어 있다. 그런데, 양자의 차압(△P)이 너무 크면 접촉형의 제1메커니컬시일(11)에서는 부하가 크게 되고, 그에 따르는 발열량도 증가하므로 휘발성이나 비등점이 낮은 피밀봉유체를 밀봉하는 경우에는, 밀봉환(12,13) 사이에 형성되는 유체윤활막이 파손될 우려가 있다. 따라서, 이와 같은 우려를 발생시키지 않기 위하여, 상기한 차압(△P)은, 밀봉조건 등에 따라서 0.5 내지 10kg/㎠의 범위에서 적당하게 설정하는 것이 좋고, 특히, 5kg/㎠정도로 하는 것이 더욱 바람직하다. 또, 퍼어지가스(G)로는 피밀봉유체의 성상에 따라 선택되는데, 일반적으로는 불활성인 질소가스 등을 사용하는 것이 바람직하다.In the purge fluid region C, purge gas G which is lower in pressure P '(= P-ΔP) than the sealed fluid pressure P is enclosed. However, when the differential pressure DELTA P is too large, the load is increased in the first mechanical seal 11 of the contact type, and the amount of heat generated accordingly increases. Therefore, when the sealed fluid having a low volatility or low boiling point is sealed, There is a fear that the fluid lubricating film formed between the (12, 13) breaks. Therefore, in order to avoid such a concern, it is preferable that the above-mentioned differential pressure ΔP is appropriately set in the range of 0.5 to 10 kg / cm 2 depending on the sealing conditions and the like, and more preferably about 5 kg / cm 2. . The purge gas G is selected depending on the properties of the hermetic fluid. In general, inert nitrogen gas or the like is preferably used.

또, 제1메커니컬시일(11)의 상대회전부분에 대해서는 플러싱액(F)이 분사되도록 되어 있다.In addition, the flushing liquid F is injected to the relative rotational portion of the first mechanical seal 11.

이상과 같이 구성된 축봉장치에 있어서는, 피밀봉유체가 고압인 경우나 액체 암모니아 등의 휘발성유체 내지 비등점이 낮은 유체인 경우에도 양호한 밀봉기능이 발휘된다.In the storage device configured as described above, a good sealing function is exhibited even when the sealed fluid is a high pressure or a volatile fluid such as liquid ammonia or a fluid having a low boiling point.

즉, 피밀봉유체영역(A)과 퍼어지유체영역(C)을 밀봉하는 제1메커니컬시일(11)에 있어서는, 피밀봉유체압력(P)이 미끄럼작동하는 제2밀봉환(13)의 배압으로서 작용하므로, 퍼어지유체압력(P' )을 위에 설명한 바와 같이 피밀봉유체압력(P)보다 저압(P-△P)으로 하여도 밀봉환(12,13)에 적정한 접촉상태로 유지할 수 있다. 따라서, 이와 같이 퍼어지유체압력(P' )을 저압으로 하므로써, 양 밀봉환(12,13)에 의한 밀봉부분에 작용하는 부하를 대폭 낮출 수 있고, 피밀봉유체의 성상이나 압력조건에 관계없이 양호하고도 안정된 밀봉기능을 발휘시킬 수 있다. 만일, 밀봉기능이 손상되었을 경우라도 피밀봉유체는 퍼어지유체영역(C)측으로 누설되므로, 종래와 같이 퍼어지유체가 피밀봉체영역(A)측으로 침입하는 일이 없다.That is, in the first mechanical seal 11 for sealing the sealed fluid region A and the purge fluid region C, the back pressure of the second sealing ring 13 in which the sealed fluid pressure P slides is operated. Since the purge fluid pressure P 'is lower than the sealed fluid pressure P (P-ΔP) as described above, it can be maintained in proper contact with the sealing rings 12 and 13. . Thus, by lowering the purge fluid pressure P 'in this manner, the load acting on the sealing portions by the two sealing rings 12 and 13 can be greatly reduced, regardless of the properties of the sealed fluid and the pressure conditions. It is possible to exert a good and stable sealing function. Even if the sealing function is impaired, the sealed fluid leaks to the purge fluid region C side, so that the purge fluid does not intrude into the sealed fluid region A side as in the prior art.

또, 제2메커니컬시일(21)에 대해서는 그것이 비접촉형 가스시일이므로, 미끄럼작동하는 제2밀봉환(23)에 배압으로서 작용하는 퍼어지가스압력(P' )이 피밀봉유체압력(P)보다 저압인 경우와 함께, 고압조건 하에서도 양호한 기능을 발휘할 수 있다.In addition, as for the second mechanical seal 21, since it is a non-contact gas seal, the purge gas pressure P 'acting as a back pressure to the sliding second sealing ring 23 is more than the sealed fluid pressure P. In addition to the case of low pressure, a good function can be exhibited even under high pressure conditions.

또, 퍼어지유체(G)가 가스이고, 대기영역(B)측의 메커니컬시일(21)을 가스밀봉으로 하고 있으므로 퍼어지유체(G)를 순환시키기 위한 주변기기는 그것을 전혀 필요로 하지 않는다.Further, since the purge fluid G is a gas and the mechanical seal 21 on the standby area B side is gas sealed, a peripheral device for circulating the purge fluid G does not need it at all.

또, 본 발명은 상기한 실시예로 한정되는 것을 아니고, 본 발명의 기본원리를 이탈하지 않는 범위 내에 있어서 적당히 개량·변경할 수 있다. 예를 들면, 제2도에 표시하는 축봉장치에서는, 각 메커니컬시일(11,21)이 제1밀봉환(12,22)을 제2밀봉환(13,23)보다 대기영역(B)쪽으로 가깝게 배치한 상태에서, 제1밀봉환(12,22)을 시일케이싱(15)에 고정, 지지함과 아울러, 제2밀봉환(13,23)을 회전축(16)에 축선방향으로의 미끄럼작동이 가능하도록 지지하여 구성된다. 또, 제3도에 표시하는 축봉장치에서는, 제1메커니컬시일(11)이 제2밀봉환(13)을 제1밀봉환(12)보다 대기영역(B)쪽으로 가깝게 배치한 상태에서, 제1밀봉환(12)을 회전축(16)에 고정, 지지함과 아울러, 제2밀봉환(13)을 시일케이싱(15)에 축선방향으로의 미끄럼작동이 가능하도록 지지하여 구성되며, 제2메커니컬시일(21)이, 제1밀봉환(22)을 제2밀봉환(23)보다 대기영역(B)쪽으로 가깝게 배치한 상태에서, 제1밀봉환(22)을 시일케이싱(15)에 고정, 지지함과 아울러, 제2밀봉환(23)을 회전축(16)에 축선방향으로의 미끄럼작동이 가능하도록 지지하여 구성된다. 또, 제4도에 표시하는 축봉장치에서는, 제1메커니컬시일(11)이 제1밀봉환(12)을 제2밀봉환(13)보다 대기영역(B)쪽으로 가깝게 배치한 상태에서, 제1밀봉환(12)을 시일케이싱(15)에 고정, 지지함과 아울러, 제2밀봉환(13)을 회전축(16)에 축선방향으로의 미끄럼작동이 가능하도록 지지하여 구성되며, 또, 제2메커니컬시일(21)이, 제2밀봉환(23)을 제1밀봉환(22)보다 대기영역(B)쪽으로 가깝게 배치한 상태에서, 제1밀봉환(22)을 회전축(16)에 고정, 지지함과 아울러, 제2밀봉환(23)을 시일케이싱(15)에 축선방향으로의 미끄럼작동이 가능하도록 지지하여 구성된다.In addition, this invention is not limited to the above-mentioned Example, It can improve suitably and change in the range which does not deviate from the basic principle of this invention. For example, in the shaft sealing device shown in FIG. 2, each mechanical seal 11, 21 makes the first sealing ring 12, 22 closer to the atmospheric region B than the second sealing ring 13, 23. In the arranged state, the first sealing rings 12 and 22 are fixed and supported to the seal casing 15, and the second sealing rings 13 and 23 are slid in the axial direction to the rotary shaft 16. It is constructed to support it. In addition, in the shaft sealing apparatus shown in FIG. 3, in the state where the 1st mechanical seal 11 arrange | positions the 2nd sealing ring 13 closer to the waiting area B than the 1st sealing ring 12, The sealing ring 12 is fixed to the rotating shaft 16, and the second sealing ring 13 is supported by the seal casing 15 so as to enable sliding in the axial direction. The first sealing ring 22 is fixed to and supported by the seal casing 15 in a state where the first sealing ring 22 is arranged closer to the standby area B than the second sealing ring 23. In addition, the second sealing ring 23 is configured to be supported by the rotating shaft 16 so as to be slidable in the axial direction. In addition, in the shaft sealing apparatus shown in FIG. 4, in the state where the 1st mechanical seal 11 arrange | positions the 1st sealing ring 12 closer to the standby area B than the 2nd sealing ring 13, The sealing ring 12 is fixed to and supported by the seal casing 15, and the second sealing ring 13 is supported on the rotating shaft 16 so as to be slidable in the axial direction. In the state where the mechanical seal 21 arrange | positions the 2nd sealing ring 23 closer to the atmospheric zone B than the 1st sealing ring 22, the 1st sealing ring 22 is fixed to the rotating shaft 16, In addition to supporting, the second sealing ring 23 is supported by the seal casing 15 so as to be able to slide in the axial direction.

Claims

Sealed area A through two purge fluid areas C formed between two mechanical seals 11 and 21 by two sets of mechanical seals 11 and 21 arranged in parallel in the axial direction of the rotating shaft 16. And a sealing device configured to close and seal the standby zone (B), wherein each mechanical seal (11, 21) has a first sealing ring (12, 22) on one side of the seal casing (15) and the rotating shaft (16) passing therethrough. ), A shaft formed by supporting the second sealing ring (l3, 23) pushed against the first sealing ring (12, 22) on the other side to enable sliding in the axial direction. In the apparatus, the first mechanical seal 11 on the side of the sealed region A is composed of a contact type seal in which the fluid pressure of the sealed region A acts as a back pressure on the second sealing ring 13, The second mechanical seal on the side of the atmospheric zone B is spread out on the second sealing ring 23, and the non-contact type seal furnace in which the fluid pressure in the fluid region C acts as a back pressure. And a purge gas (G) such as nitrogen gas having a lower pressure than the sealed fluid, is injected into the purge fluid region (C).

The first sealing according to claim 1, wherein each of the mechanical seals (11, 21) is arranged closer to the atmospheric zone (B) than the first sealing rings (12, 22). The ring 12 and 22 are fixed and supported on the rotating shaft 16, and the second sealing rings 13 and 23 are supported by the seal casing 15 so as to be able to slide in the axial direction. Shaft device made of.

The method of claim 1, wherein each of the mechanical seals (11, 21), the first sealing ring (12, 22) is arranged closer to the standby area (B) than the second sealing ring (13, 23), the first It is configured to fix and support the sealing rings (12, 22) to the seal casing (15), and to support the second sealing rings (13, 23) to the rotating shaft (16) to enable sliding in the axial direction. A shaft device characterized in that.

The first sealing ring (12) according to claim 1, wherein the first mechanical seal (11) is arranged closer to the standby area (B) than the first sealing ring (12) than the first sealing ring (12). And the second sealing ring 13 to the seal casing 15 so as to be slidable in the axial direction, and the second mechanical seal 21 is fixed. The first sealing ring 22 is fixed to and supported by the seal casing 15 in a state where the first sealing ring 22 is disposed closer to the atmospheric region B than the second sealing ring 23, A shaft rod device, characterized in that configured to support the sealing ring (23) in the axial direction to the sliding shaft (16).

The first sealing ring 12 is placed on the seal casing 15 in a state where the first mechanical seal 11 is arranged closer to the standby area B than the second sealing ring 13. In addition to being fixed and supported, the second sealing ring 13 is supported on the rotational shaft 16 so as to be slidable in the axial direction, and the second mechanical seal 21 is the second sealing ring 23. In the state in which is disposed closer to the standby area B than the first sealing ring 22, the first sealing ring 22 is fixed and supported on the rotating shaft 16, and the second sealing ring 23 is sealed. A shaft rod device, characterized in that configured to support the casing (15) to enable sliding in the axial direction.

The storage device according to claim 1, wherein the pressure difference between the purge gas (G) and the sealed fluid is 0.5 to 10 kg / cm 2.

The storage device according to claim 1, wherein the pressure difference between the purge gas (G) and the sealed fluid is 5 kg / cm 2.

2. A storage device according to claim 1, wherein the flushing liquid (F) is sprayed toward the contact portion of both sealing rings (12, 13) in the first mechanical seal (11).