JP2006083889A - Tandem type dry contact shaft seal device - Google Patents

Tandem type dry contact shaft seal device Download PDF

Info

Publication number
JP2006083889A
JP2006083889A JP2004266756A JP2004266756A JP2006083889A JP 2006083889 A JP2006083889 A JP 2006083889A JP 2004266756 A JP2004266756 A JP 2004266756A JP 2004266756 A JP2004266756 A JP 2004266756A JP 2006083889 A JP2006083889 A JP 2006083889A
Authority
JP
Japan
Prior art keywords
seal
region
sealing ring
ring
stationary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2004266756A
Other languages
Japanese (ja)
Other versions
JP4000324B2 (en
Inventor
Masaki Miyamoto
正樹 宮本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Pillar Packing Co Ltd
Original Assignee
Nippon Pillar Packing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Pillar Packing Co Ltd filed Critical Nippon Pillar Packing Co Ltd
Priority to JP2004266756A priority Critical patent/JP4000324B2/en
Publication of JP2006083889A publication Critical patent/JP2006083889A/en
Application granted granted Critical
Publication of JP4000324B2 publication Critical patent/JP4000324B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tandem type dry contact shaft seal device for suppressing the leakage of gas of gasified process liquid into atmospheric air. <P>SOLUTION: First and second mechanical seals 3, 4 have rotary sealing rings 7, 15 provided on a rotating shaft 2, static sealing rings 11, 17 provided on a shaft seal portion casing 1, and springs 12, 18 for thrusting and energizing one sealing ring to the other sealing ring, respectively. The static sealing ring 17 of the second mechanical seal 4 has a communication passage 31 for communicating a back region of the static sealing ring 17 with an annular recessed groove 30 formed in a sealing end face 17a of the static sealing ring 17. A first throttle portion 23 is formed in a flow path which communicates the back region of the static sealing ring 17 of the second mechanical seal 4 to which purge gas is supplied with an outer periphery outward region E of a sealing end face 17a of the static sealing ring 17 of the second mechanical seal 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、２組のメカニカルシールが回転軸の軸方向に沿って並列配置されており、ポンプやミキサー等の回転機器に使用されるタンデム型ドライコンタクト軸封装置に関する。   The present invention relates to a tandem dry contact shaft seal device in which two sets of mechanical seals are arranged in parallel along the axial direction of a rotation shaft, and used for a rotary device such as a pump or a mixer.

従来より、揮発性の液体を扱う産業用プロセスポンプやミキサー等の回転機器の軸封装置として、２組のメカニカルシールが前記回転機器の回転軸の軸方向に沿って並列配置されたタンデム型軸封装置が用いられている。このような軸封装置では、プロセス液が気化することにより発生した気体が大気側に漏れるのを抑制するために、例えば両メカニカルシール間に画成された軸封空間に潤滑油等のサーキュレーション液を充填し、このサーキュレーション液を、大気側のメカニカルシールに設けられたパーシャルインペラによって、軸封装置の外周に配設されたリザーバタンクとの間で強制循環させることが行われている（例えば、特許文献１参照）。
しかしながら、サーキュレーション液を強制循環させる方式では、リザーバタンクを別途設ける必要があり、そのためのスペースを要するのでシステムのコンパクト化を図ることができず、またコストアップの要因となっていた。さらに、良好なシール効果を得るためには、サーキュレーション液の品質劣化等を常時管理する必要があり、また、使用済のサーキュレーション液を処分しなければならず、手間がかかっていた。 Conventionally, as a shaft seal device for rotating equipment such as industrial process pumps and mixers that handle volatile liquids, two sets of mechanical seals are arranged in parallel along the axial direction of the rotating shaft of the rotating equipment. A sealing device is used. In such a shaft seal device, in order to prevent the gas generated by the vaporization of the process liquid from leaking to the atmosphere side, for example, in the shaft seal space defined between the two mechanical seals, circulation of lubricating oil or the like is performed. The liquid is filled, and this circulation liquid is forcibly circulated between a reservoir tank provided on the outer periphery of the shaft seal device by a partial impeller provided on a mechanical seal on the atmosphere side ( For example, see Patent Document 1).
However, in the method of forcibly circulating the circulation liquid, it is necessary to separately provide a reservoir tank, and a space for that is required, so that the system cannot be made compact and the cost is increased. Furthermore, in order to obtain a good sealing effect, it is necessary to always manage the deterioration of the quality of the circulation liquid, and the used circulation liquid must be disposed of, which is troublesome.

そこで、このようなサーキュレーション液循環方式における問題点を解決するために、二次側（大気側）にドライコンタクトシールを配置したタンデム型軸封装置が提案されている。この軸封装置では、図３に示されるように、回転機器の回転軸５０の廻りに配設された軸封部ケーシング５１に形成された供給路５２を介してパージガスが二次側シール５３の外周の領域Ｆに供給される。このパージガスは、前記軸封ケーシング５１の内周面に形成された環状凸部５５の先端面５５ａと、二次側シール５３の回転密封環６０が固定されるスリーブ５０ａの環状鍔部６２の外周面６２ａとの間の狭路５６を通って回転密封環６０の背部の領域Ｇに至り、ついで軸封ケーシング５１に形成された排出路５８を通って装置外に排出される。その際、前記狭路５６を高速で通過するパージガスの流れによって、プロセス液が気化することにより発生した気体が大気側領域Ｈに漏れるのを抑制している。   Therefore, in order to solve such problems in the circulation liquid circulation system, a tandem shaft seal device in which a dry contact seal is arranged on the secondary side (atmosphere side) has been proposed. In this shaft seal device, as shown in FIG. 3, the purge gas passes through the supply passage 52 formed in the shaft seal casing 51 disposed around the rotation shaft 50 of the rotary device, and the purge gas is discharged from the secondary side seal 53. It is supplied to the peripheral region F. This purge gas is generated at the outer periphery of the annular flange 62 of the sleeve 50a to which the tip end surface 55a of the annular convex portion 55 formed on the inner peripheral surface of the shaft seal casing 51 and the rotary seal ring 60 of the secondary side seal 53 are fixed. It passes through a narrow path 56 between the surface 62a and reaches a region G at the back of the rotary seal ring 60, and then is discharged out of the apparatus through a discharge path 58 formed in the shaft seal casing 51. At this time, the gas generated by the vaporization of the process liquid is prevented from leaking to the atmosphere side region H by the flow of the purge gas passing through the narrow path 56 at a high speed.

特開平７−１２２３８号公報Japanese Patent Laid-Open No. 7-12238

しかしながら、パージガスの供給口は１箇所であるため、前記二次側シール５３の外周全体において均一なガスの流れを作ることは困難であり、そのため前記回転密封環６０の密封端面と静止密封環５９の密封端面とで形成されるシール面から、前記気化した気体とパージガスとの混合ガスが大気側領域Ｈに漏れる惧れがある。プロセス液が気化した気体の中には、有害なものがあり、かかる気体の大気中への漏れは好ましくない。   However, since there is only one purge gas supply port, it is difficult to create a uniform gas flow over the entire outer periphery of the secondary side seal 53. For this reason, the sealing end face of the rotary sealing ring 60 and the stationary sealing ring 59 are difficult. There is a possibility that the mixed gas of the vaporized gas and the purge gas leaks to the atmosphere side region H from the sealing surface formed by the sealing end surface. Some gases in which the process liquid is vaporized are harmful, and leakage of such gases into the atmosphere is not preferable.

本発明は、このような従来技術の有する問題点を解消するためになされたものであり、プロセス液が気化した気体の大気中への漏れを抑制することができるタンデム型ドライコンタクト軸封装置を提供することを目的としている。   The present invention has been made to solve such problems of the prior art, and a tandem dry contact shaft seal device capable of suppressing leakage of gas, which is vaporized process liquid, into the atmosphere. It is intended to provide.

本発明のタンデム型ドライコンタクト軸封装置は、回転機器の機内領域と機外領域とを区画する軸封部ケーシングと、この軸封部ケーシングを洞貫する回転軸との間に、当該回転軸の軸線方向に並列する、機内側の第１メカニカルシール及び機外側の第２メカニカルシールが配置されているタンデム型ドライコンタクト軸封装置であって、
前記第１及び第２メカニカルシールは、それぞれ、前記回転軸に設けられた回転密封環と、前記軸封部ケーシングに設けられた静止密封環と、一方の密封環を他方の密封環へと押圧付勢するスプリングとを備えており、
前記第２メカニカルシールの静止密封環の背部には、当該静止密封環の背面にパージガスを供給する複数の供給ポートが周方向に所定間隔で配設されており、
前記第２メカニカルシールの静止密封環は、この静止密封環の背部領域と、当該静止密封環の密封端面に形成された環状凹溝とを連通する連通路を有しており、且つ
前記パージガスが供給される第２メカニカルシールの静止密封環の背部領域と、当該第２メカニカルシールの静止密封環の密封端面の外周外方領域とを連通する流路に第１絞り部が形成されていることを特徴としている。 The tandem dry contact shaft sealing device of the present invention includes a rotating shaft between a shaft sealing casing that divides an in-machine region and an out-of-machine region of a rotating device, and a rotating shaft that penetrates the shaft sealing portion casing. A tandem dry contact shaft seal device in which a first mechanical seal inside the machine and a second mechanical seal outside the machine are arranged in parallel in the axial direction of
The first mechanical seal and the second mechanical seal respectively press a rotary seal ring provided on the rotary shaft, a stationary seal ring provided on the shaft seal casing, and one seal ring to the other seal ring. With a spring to bias,
On the back of the stationary seal ring of the second mechanical seal, a plurality of supply ports for supplying purge gas to the back surface of the stationary seal ring are arranged at predetermined intervals in the circumferential direction.
The stationary sealing ring of the second mechanical seal has a communication path that communicates the back region of the stationary sealing ring and an annular groove formed in the sealing end surface of the stationary sealing ring, and the purge gas is The first throttle portion is formed in a flow path that communicates the back region of the stationary seal ring of the second mechanical seal to be supplied and the outer peripheral region of the sealing end surface of the stationary seal ring of the second mechanical seal. It is characterized by.

本発明のタンデム型ドライコンタクト軸封装置は、第２メカニカルシールの静止密封環の背部において周方向に所定間隔で配設された複数の供給ポートから当該静止密封環の背部領域にパージガスが供給されるので、第２メカニカルシールの外周全体において均一なガスの流れを作ることができる。そして、このガスは第１絞り部を通って第２メカニカルシールの静止密封環の密封端面の外周外方領域へと流れるが、第１絞り部を通ることで圧力損失が発生するため、前記静止密封環の密封端面の外周外方領域におけるパージガスの圧力は当該静止密封環の背部領域におけるパージガスの圧力よりも小さくなる。また、第２メカニカルシールの静止密封環には、この静止密封環の背部領域と、当該静止密封環の密封端面に形成された環状凹溝とを連通する連通路が形成されており、しかも前記環状凹溝からのガスの漏れは僅かであるので当該連通路内のガスの流れはほとんどなく、そのため静止密封環の背部領域におけるパージガスの圧力と、前記環状凹溝内のパージガスの圧力は略等しくなる。その結果、この環状凹溝内の圧力を、静止密封環の密封端面の外周外方領域の圧力よりも大きく保つことができ、プロセス液が気化した気体とパージガスとの混合ガスが前記環状凹溝内に、すなわち第２メカニカルシールのシール面に浸入して大気領域へ漏れるのを抑制することができる。   In the tandem dry contact shaft seal device of the present invention, purge gas is supplied to the back region of the stationary seal ring from a plurality of supply ports arranged at predetermined intervals in the circumferential direction at the back portion of the stationary seal ring of the second mechanical seal. Thus, a uniform gas flow can be created over the entire outer periphery of the second mechanical seal. This gas flows through the first throttle part to the outer peripheral outer region of the sealing end face of the stationary seal ring of the second mechanical seal, but pressure loss is generated by passing through the first throttle part. The purge gas pressure in the outer peripheral region of the sealing end face of the sealing ring is smaller than the purge gas pressure in the back region of the stationary sealing ring. Further, the stationary sealing ring of the second mechanical seal is formed with a communication path that communicates the back region of the stationary sealing ring and the annular concave groove formed on the sealing end surface of the stationary sealing ring, and Since there is little gas leakage from the annular groove, there is almost no gas flow in the communication path, so that the pressure of the purge gas in the back region of the stationary seal ring and the pressure of the purge gas in the annular groove are substantially equal. Become. As a result, the pressure in the annular groove can be kept larger than the pressure in the outer peripheral region of the sealing end face of the stationary seal ring, and the mixed gas of the gas vaporized from the process liquid and the purge gas is the annular groove. It is possible to suppress intrusion into the inside, that is, the seal surface of the second mechanical seal and leak into the atmosphere region.

前記第２メカニカルシールの静止密封環の密封端面の外周外方領域と、当該第２メカニカルシールの回転密封環の背部領域であって前記パージガスの排出口が開口している領域とを連通する流路に第２絞り部が形成されているのが好ましい。この第２絞り部を通るパージガスの流れによって、プロセス液が気化することにより発生した気体が、静止密封環の密封端面の外周外方領域に漏れるのを抑制することができる。   A flow that communicates between the outer peripheral outer region of the sealing end surface of the stationary sealing ring of the second mechanical seal and the region that is the back region of the rotary sealing ring of the second mechanical seal and that is open to the purge gas discharge port. It is preferable that a second throttle portion is formed in the path. The flow of the purge gas passing through the second throttle portion can suppress the gas generated by the vaporization of the process liquid from leaking to the outer peripheral area of the sealing end face of the stationary sealing ring.

また、前記パージガスの供給路が前記軸封部ケーシングに形成されており、この供給路に連通するように環状のガスヘッダーが当該軸封部ケーシングの内周部に設けられており、且つ、前記ガスヘッダーが、前記供給路に連通して接続される広路と、この広路と連通しており、当該広路よりも前記回転軸を基準とした半径方向の寸法が小さい狭路とで構成されているのが好ましい。このように広路と狭路とからなるガスヘッダーを設けると、供給路からガスヘッダーの広路に供給されたパージガスは、広路のほうが狭路よりも圧力損失が小さいので、その多くが前記広路を周方向に流れる。その結果、ガスヘッダーの全周に均等にパージガスを供給することができる。   The purge gas supply path is formed in the shaft seal casing, and an annular gas header is provided in the inner periphery of the shaft seal casing so as to communicate with the supply path. A gas header is configured by a wide path connected to the supply path and a narrow path that is in communication with the wide path and has a smaller radial dimension with respect to the rotation axis than the wide path. Is preferred. When a gas header composed of a wide path and a narrow path is provided in this way, the purge gas supplied from the supply path to the wide path of the gas header has a smaller pressure loss in the wide path than in the narrow path. Flow in the direction. As a result, the purge gas can be evenly supplied to the entire circumference of the gas header.

さらに、前記環状のガスヘッダーが、前記軸封部ケーシングの内周面に形成された環状の深溝と、この深溝と並設された環状の浅溝と、両溝を覆うように前記軸封部ケーシングの内周面に当接して固定された短円筒体とで形成されており、且つ、前記短円筒体における、前記浅溝を覆う部分にパージガスを供給する複数の供給ポートが形成されているのが好ましい。このようにして、軸封部ケーシングに形成した溝とこの溝を覆う短円筒体とでガスヘッダーを構成することで、部品数を減らして構造を簡略化することができる。   Further, the annular gas header covers the annular seal groove so as to cover the annular deep groove formed on the inner peripheral surface of the shaft seal casing, the annular shallow groove arranged in parallel with the deep groove, and both grooves. And a plurality of supply ports for supplying purge gas to a portion of the short cylinder that covers the shallow groove. Is preferred. In this way, by forming the gas header with the groove formed in the shaft seal casing and the short cylindrical body covering the groove, the number of parts can be reduced and the structure can be simplified.

本発明のタンデム型ドライコンタクト軸封装置は、第２メカニカルシールの静止密封環の密封端面に形成された環状凹溝内におけるパージガスの圧力を、静止密封環の密封端面の外周外方領域におけるパージガスの圧力よりも大きく保つことができるので、プロセス液が気化した気体とパージガスとの混合ガスが前記環状凹溝内に、すなわち第２メカニカルシールのシール面に浸入して大気側へ漏れるのを抑制することができる。   The tandem dry contact shaft seal device according to the present invention is configured so that the pressure of the purge gas in the annular groove formed in the sealing end surface of the stationary sealing ring of the second mechanical seal is changed to the purge gas in the outer peripheral region of the sealing end surface of the stationary sealing ring. Therefore, it is possible to prevent the gas mixture of the process liquid and purge gas from entering the annular groove, that is, entering the sealing surface of the second mechanical seal and leaking to the atmosphere side. can do.

以下、添付図面に基づいて、本発明のタンデム型ドライコンタクト軸封装置の実施の形態を詳細に説明する。
図１は、本発明の一実施の形態に係るタンデム型ドライコンタクト軸封装置Ｔ（以下、単に軸封装置ともいう）の断面説明図である。この軸封装置Ｔは、ポンプやミキサー等の回転機器の機内領域と機外領域とを区画する軸封部ケーシング１と、この軸封部ケーシング１を洞貫する回転軸２との間に、当該回転軸２の軸線方向に並列する、機内側の第１メカニカルシール３及び機外側の第２メカニカルシール４が配置されているタンデム型ドライコンタクト軸封装置である。なお、図１において、左が機外側、右が機内側である。 Embodiments of a tandem dry contact shaft sealing device according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional explanatory view of a tandem dry contact shaft seal device T (hereinafter also simply referred to as a shaft seal device) according to an embodiment of the present invention. The shaft seal device T is provided between a shaft seal casing 1 that partitions an in-machine region and an external region of a rotary device such as a pump or a mixer, and a rotary shaft 2 that penetrates the shaft seal casing 1. This is a tandem dry contact shaft seal device in which a first mechanical seal 3 on the inside of the machine and a second mechanical seal 4 on the outside of the machine are arranged in parallel in the axial direction of the rotary shaft 2. In FIG. 1, the left is the outboard side and the right is the inboard side.

機内側の第１メカニカルシール３は、回転軸２のスリーブ２ａにＯリング５でシールした状態でホロセットボルト８により固定されたリテーナ３５に、Ｏリング６でシールし
た状態で軸線方向摺動可能に且つ相対回転不能に保持された回転密封環７と、前記軸封部ケーシング１にＯリング９でシールした状態でピン１０により固定された静止密封環１１と、前記回転密封環７を静止密封環１１へと押圧付勢するスプリング１２とを備えている。この第１メカニカルシール３では、両密封環７、１１の対向端面である密封端面７ａ、１１ａの相対回転摺接作用により、被密封流体領域Ａと、後述するパージガスの排出領域Ｂとをシール（一次シール）している。なお、静止密封環１１はセラミックスや超硬合金等の硬質材で作製され、一方、回転密封環７は静止密封環１１より比較的軟質の材料、例えばカーボン等で作製されている。 The first mechanical seal 3 on the inside of the machine is slidable in the axial direction while being sealed with an O-ring 6 on a retainer 35 fixed by a holoset bolt 8 while being sealed with a sleeve 2a of a rotary shaft 2 with an O-ring 5 And a rotary seal ring 7 held in a relatively non-rotatable manner, a stationary seal ring 11 fixed to the shaft seal casing 1 with a pin 10 in a state of being sealed with an O-ring 9, and the rotary seal ring 7 being statically sealed. A spring 12 that presses and urges the ring 11 is provided. The first mechanical seal 3 seals a sealed fluid region A and a purge gas discharge region B, which will be described later, by the relative rotational sliding contact action of the sealing end surfaces 7a and 11a, which are the opposite end surfaces of the both sealing rings 7 and 11. Primary seal). The stationary seal ring 11 is made of a hard material such as ceramics or cemented carbide, while the rotary seal ring 7 is made of a material that is relatively softer than the stationary seal ring 11, such as carbon.

二次シールとして機能する機外側の第２メカニカルシール４は、前記第１メカニカルシール３の前方位置（機外側）に配置されており、当該第１メカニカルシール３と同様に、回転軸２のスリーブ２ａにＯリング１３でシールした状態でピン１４により固定された回転密封環１５と、前記軸封部ケーシング１にＯリング１６でシールした状態で軸線方向摺動可能に且つ相対回転不能に固定された静止密封環１７と、この静止密封環１７を前記回転密封環１５へと押圧付勢するスプリング１８とを備えている。この第２メカニカルシール４では、両密封環１５、１７の対向端面である密封端面１５ａ、１７ａの相対回転摺接作用により、パージガスの排出領域Ｂと、大気領域Ｃとをシール（二次シール）している。なお、回転密封環１５はセラミックスや超硬合金等の硬質材で作製され、一方、静止密封環１７は回転密封環１５より比較的軟質の材料、例えばカーボン等で作製されている。   A second mechanical seal 4 on the outside of the machine that functions as a secondary seal is disposed in front of the first mechanical seal 3 (on the outside of the machine), and similarly to the first mechanical seal 3, the sleeve of the rotating shaft 2. Rotating sealing ring 15 fixed by pin 14 in a state sealed with O-ring 13 in 2a, and axially slidable in a state sealed with O-ring 16 in shaft sealing portion casing 1 and fixed in a relatively non-rotatable manner. The stationary sealing ring 17 and a spring 18 that presses and urges the stationary sealing ring 17 toward the rotary sealing ring 15 are provided. In the second mechanical seal 4, the purge gas discharge region B and the atmospheric region C are sealed (secondary seal) by the relative rotational sliding contact action of the sealing end surfaces 15 a and 17 a which are the opposite end surfaces of the both sealing rings 15 and 17. is doing. The rotary seal ring 15 is made of a hard material such as ceramics or cemented carbide, while the stationary seal ring 17 is made of a material that is relatively softer than the rotary seal ring 15, such as carbon.

前記第２メカニカルシール４の静止密封環１７の密封端面１７ａには環状凹溝３０が形成されており、また当該静止密封環１７には、この静止密封環１７の背部領域Ｄと前記環状凹溝３０とを連通する連通路３１が形成されている。この連通路３１の数は、本発明において特に限定されるものではないが、通常、３〜１６本程度である。   An annular groove 30 is formed in the sealing end face 17a of the stationary seal ring 17 of the second mechanical seal 4, and the back region D of the stationary seal ring 17 and the annular groove are formed in the stationary seal ring 17. A communication path 31 that communicates with 30 is formed. The number of the communication passages 31 is not particularly limited in the present invention, but is usually about 3 to 16.

前記軸封部ケーシング１には、第２メカニカルシール４の静止密封環１７の背部領域Ｄにパージガスを供給する供給路１９、及びパージガスの排出領域Ｂからパージガスを排出する排出路２０が形成されている。パージガスとしては、被密封流体領域Ａ又は大気領域Ｃに漏洩しても支障のないガスが使用されるが、通常、被密封流体と不活性であり且つ無害な窒素ガスが使用される。   The shaft seal portion casing 1 is provided with a supply passage 19 for supplying purge gas to the back region D of the stationary seal ring 17 of the second mechanical seal 4 and a discharge passage 20 for discharging purge gas from the purge gas discharge region B. Yes. As the purge gas, a gas that does not interfere with leakage into the sealed fluid region A or the atmospheric region C is used. Usually, nitrogen gas that is inert and harmless with the sealed fluid is used.

前記供給路１９は、軸封部ケーシング１の内周部に形成された環状のガスヘッダー２１に開口しており、このガスヘッダー２１によりパージガスを第２メカニカルシール４の静止密封環１７の外周全体に均一に行き渡らせることができる。前記ガスヘッダー２１は、パージガスの供給路１９が連通して開口する広路２１ａと、この広路２１ａよりも半径方向（回転軸２を基準として半径方向のことであり、図１〜２においては上下方向である）の寸法が小さい狭路２１ｂとで構成されており、前記広路２１ａと狭路２１ｂは互いに連通するように回転軸２の軸方向に沿って並設されている。本実施の形態では、前記広路２１ａ及び狭路２１ｂは、軸封部ケーシング１の内周面１ａに形成された環状の深溝と、この深溝と並設された環状の浅溝と、両溝を覆うように前記軸封部ケーシング１の内周面１ａに当接して固定された短円筒体２４とで形成されている。前記狭路２１ｂは広路２１ａよりも半径方向の寸法が小さいので、パージガスが通過する際の抵抗、すなわち圧力損失は広路２１ａを通過する際のものよりも大きくなる。したがって、供給路１９から広路２１ａに供給されたパージガスは、その多くが圧力損失の小さい広路２１ａを周方向に流れようとし、その結果、環状のガスヘッダー２１の全周において均等にパージガスを供給することができる。   The supply passage 19 is open to an annular gas header 21 formed in the inner peripheral portion of the shaft seal casing 1, and purge gas is supplied to the entire outer periphery of the stationary sealing ring 17 of the second mechanical seal 4 by the gas header 21. Can be evenly distributed. The gas header 21 has a wide passage 21a in which a purge gas supply passage 19 communicates and opens, and a radial direction with respect to the wide passage 21a (the radial direction with reference to the rotary shaft 2; in FIGS. The narrow path 21b has a small dimension, and the wide path 21a and the narrow path 21b are juxtaposed along the axial direction of the rotary shaft 2 so as to communicate with each other. In the present embodiment, the wide path 21a and the narrow path 21b include an annular deep groove formed in the inner peripheral surface 1a of the shaft seal casing 1, an annular shallow groove arranged in parallel with the deep groove, and both grooves. It is formed with a short cylindrical body 24 fixed in contact with the inner peripheral surface 1a of the shaft seal casing 1 so as to cover it. Since the narrow path 21b has a smaller radial dimension than the wide path 21a, the resistance when the purge gas passes, that is, the pressure loss, is larger than that when passing through the wide path 21a. Accordingly, most of the purge gas supplied from the supply passage 19 to the wide passage 21 a tends to flow in the circumferential direction through the wide passage 21 a with a small pressure loss, and as a result, the purge gas is supplied uniformly over the entire circumference of the annular gas header 21. be able to.

パージガスは、前記短円筒体２４において、前記浅溝を覆う部分に形成された複数の供給ポート２２から静止密封環１７の背部の領域Ｄに供給される。この供給ポート２２は、短円筒体２４の周方向に沿って所定間隔で配列されており、その形状は、本発明において特に限定されるものではなく、丸孔、長孔、矩形の孔等適宜の形状を採用することができる。また、図１〜２に示される実施の形態のように、短円筒体２４の縁部に半円形や矩形の切欠を形成し、この切欠を供給ポート２２とすることもできる。図１〜２に示される実施の形態では、短円筒体２４の縁部を第２メカニカルシール４の静止密封環１７のリテーナ３４に当接させて、前記切欠とリテーナ３４の表面とで供給ポート２２を構成している。   The purge gas is supplied from the plurality of supply ports 22 formed in the portion covering the shallow groove in the short cylindrical body 24 to the region D at the back of the stationary sealing ring 17. The supply ports 22 are arranged at predetermined intervals along the circumferential direction of the short cylindrical body 24, and the shape thereof is not particularly limited in the present invention, and a round hole, a long hole, a rectangular hole or the like is appropriately used. The shape can be adopted. Also, as in the embodiment shown in FIGS. 1 and 2, a semicircular or rectangular cutout may be formed at the edge of the short cylindrical body 24, and this cutout may be used as the supply port 22. In the embodiment shown in FIGS. 1 and 2, the edge of the short cylindrical body 24 is brought into contact with the retainer 34 of the stationary sealing ring 17 of the second mechanical seal 4, and the supply port is formed by the notch and the surface of the retainer 34. 22 is constituted.

供給ポート２２は、短円筒体２４の周方向において等ピッチで配置してもよいが、パージガスの供給路１９から離れるにしたがい徐々にピッチを小さくすると、さらに均等にパージガスを静止密封環１７の背部の領域Ｄに供給することができる。さらに、等しいピッチで供給ポート２２を配置する場合、当該供給ポート２２の大きさをすべて同一にしてもよいが、パージガスの供給路１９から離れるにしたがい徐々にサイズを大きくすると、より均等にパージガスを静止密封環１７の背部の領域Ｄに供給することができる。なお、供給ポート２２のピッチとサイズは、両方とも変化させるようにしてもよい。   The supply ports 22 may be arranged at an equal pitch in the circumferential direction of the short cylindrical body 24, but when the pitch is gradually reduced as the distance from the purge gas supply path 19 is increased, the purge gas is more evenly distributed to the back of the stationary seal ring 17. Can be supplied to the region D. Further, when the supply ports 22 are arranged at the same pitch, the sizes of the supply ports 22 may all be the same. However, as the size is gradually increased as the distance from the purge gas supply path 19 increases, the purge gas is more evenly distributed. It can be supplied to the region D at the back of the stationary sealing ring 17. Note that both the pitch and the size of the supply port 22 may be changed.

静止密封環１７の背部の領域Ｄと、当該静止密封環７の密封端面１７ａの外周外方領域Ｅとを連通する流路には、第１絞り部２３が形成されている。本実施の形態では、この第１絞り部２３は、静止密封環１７の外周面１７ｂと、軸封部ケーシング１の内周面に当接して固定された前記短円筒体２４の内周面２４ａとで構成されている。前記外周面１７ｂと内周面２４ａ間の距離、すなわち第１絞り部２３の幅（図1〜２において上下方向の寸法）は、パージガスの流れの円滑性や後述する圧力損失の効果等を考慮して選定され、本発明において特に限定されるものではないが、通常、２５０〜２５μｍ（内周面２４ａと外周面１７ｂの直径の差で表すと５００〜５０μｍ）程度である。   A first restricting portion 23 is formed in a flow path that connects the region D of the back portion of the stationary seal ring 17 and the outer peripheral outer region E of the sealed end surface 17 a of the stationary seal ring 7. In the present embodiment, the first throttle portion 23 has an outer peripheral surface 17 b of the stationary seal ring 17 and an inner peripheral surface 24 a of the short cylindrical body 24 fixed in contact with the inner peripheral surface of the shaft seal portion casing 1. It consists of and. The distance between the outer peripheral surface 17b and the inner peripheral surface 24a, that is, the width of the first throttle portion 23 (the vertical dimension in FIGS. 1 and 2) takes into account the smoothness of the purge gas flow and the effect of pressure loss described later. Although not particularly limited in the present invention, it is usually about 250 to 25 μm (500 to 50 μm in terms of the difference in diameter between the inner peripheral surface 24a and the outer peripheral surface 17b).

複数の供給ポート２２から静止密封環１７の背部領域Ｄに供給されたパージガスは、前記第１絞り部２３を通って静止密封環７の密封端面１７ａの外周外方領域Ｅへと流れるが、狭い第１絞り部２３を通過する間に圧力損失が発生するため、領域Ｅにおけるパージガスの圧力ＰＥは、領域Ｄにおけるパージガスの圧力ＰＤよりも小さくなる。すなわち、ＰＥ＜ＰＤの関係が成立する。また、前記環状凹溝３０から両密封端面１５ａ、１７ａ間の隙間を経由して周辺領域に漏れるパージガスの量は僅かであるので、前記連通路３１内のパージガスの流れはほとんどなく、そのため静止密封環１７の背部領域Ｄにおけるパージガスの圧力ＰＤと、前記環状凹溝３１内のパージガスの圧力Ｐは略等しくなる。すなわち、ＰＤ＝Ｐの関係が成立する。その結果、この環状凹溝３１内のパージガスの圧力Ｐを、静止密封環１７の密封端面１７ａの外周外方領域Ｅの圧力ＰＥよりも大きく保つことができ（ＰＥ＜Ｐ）、たとえプロセス液が気化した気体が領域Ｅに流れ込んだとしても、かかる気体とパージガスとの混合ガスが前記環状凹溝３１内に、すなわち第２メカニカルシール４のシール面に浸入して大気領域Ｃへ漏れるのを抑制することができる。 The purge gas supplied from the plurality of supply ports 22 to the back region D of the stationary sealing ring 17 flows through the first throttle 23 to the outer peripheral region E of the sealing end surface 17a of the stationary sealing ring 7, but is narrow. Since a pressure loss occurs while passing through the first throttle 23, the purge gas pressure P E in the region E is smaller than the purge gas pressure P D in the region D. That is, the relationship P E <P D is established. Further, since the amount of purge gas leaking from the annular concave groove 30 to the peripheral region via the gap between both sealed end faces 15a and 17a is small, there is almost no flow of purge gas in the communication path 31, and therefore static sealing is achieved. and pressure P D of the purge gas in the dorsal region D of the ring 17, the pressure P in the purge gas in the annular concave groove 31 is substantially equal. That is, the relationship P D = P is established. As a result, the pressure P in the purge gas in the annular groove 31, the stationary seal ring 17 sealing end face 17a outside outer side can be maintained higher than the pressure P E in the region E of the (P E <P), even if the process Even if the gas in which the liquid is vaporized flows into the region E, the mixed gas of the gas and the purge gas enters the annular groove 31, that is, enters the seal surface of the second mechanical seal 4 and leaks into the atmospheric region C. Can be suppressed.

本実施の形態では、前記第２メカニカルシール４の静止密封環１７の密封端面１７ａの外周外方領域Ｅと、当該第２メカニカルシール４の回転密封環１７の背部領域であって前記パージガスの排出口２０ａが開口している領域、すなわちパージガスの排出領域Ｂとを連通する流路に第２絞り部２５が形成されている。この第２絞り部２５は、回転密封環１５が固定されるスリーブ２ａの環状鍔部３２の外周面３２ａと、軸封部ケーシング１の内周面に突出形成された環状リブ３３の内周面３３ａとで構成されている。この第２絞り部２５を通ることでパージガスに圧力損失が発生するため、前記第２メカニカルシール４の静止密封環１７の密封端面１７ａの外周外方領域Ｅにおけるパージガスの圧力ＰＥよりも排出領域Ｂにおけるパージガスの圧力ＰＢが小さくなる（ＰＢ＜ＰＥ）。この差圧とパージガスの流れによって、プロセス液が気化することにより発生した気体が、静止密封環１７の密封端面１７ａの外周外方領域Ｅに漏れるのを抑制することができる。 In the present embodiment, the outer peripheral outer region E of the sealing end surface 17a of the stationary sealing ring 17 of the second mechanical seal 4 and the back region of the rotary sealing ring 17 of the second mechanical seal 4 are exhausted of the purge gas. A second throttle portion 25 is formed in a flow path that communicates with a region where the outlet 20a is open, that is, a purge gas discharge region B. The second restricting portion 25 includes an outer peripheral surface 32a of the annular flange 32 of the sleeve 2a to which the rotary seal ring 15 is fixed, and an inner peripheral surface of an annular rib 33 formed to protrude from the inner peripheral surface of the shaft seal casing 1. 33a. Thus the second pressure loss in the purge gas by passing through the throttle portion 25 is generated, the discharge region than the pressure P E of the purge gas in the outer peripheral outer region E of the sealing end face 17a of the stationary seal ring 17 of the second mechanical seal 4 The pressure P B of the purge gas at B becomes smaller (P B <P E ). By this differential pressure and the flow of the purge gas, it is possible to suppress the gas generated by the vaporization of the process liquid from leaking to the outer peripheral outer region E of the sealing end surface 17a of the stationary sealing ring 17.

なお、前述した実施の形態では、溝と短円筒体を用いてパージガスを周方向に供給しているが、これ以外に、例えば前記供給路１９に連通して接続された環状のダクト（このダクトの内周面には複数の供給ポートが形成されている）を用いることもできる。   In the above-described embodiment, the purge gas is supplied in the circumferential direction using the groove and the short cylindrical body. However, in addition to this, for example, an annular duct connected in communication with the supply path 19 (this duct) A plurality of supply ports are formed on the inner peripheral surface of the same.

本発明の軸封装置の一実施の形態の断面説明図である。It is a section explanatory view of one embodiment of the shaft seal device of the present invention. 図１に示される軸封装置の要部断面説明図である。It is principal part cross-sectional explanatory drawing of the shaft-seal apparatus shown by FIG. 従来のタンデム型軸封装置の断面説明図である。It is sectional explanatory drawing of the conventional tandem-type shaft seal apparatus.

符号の説明Explanation of symbols

１軸封部ケーシング
２回転軸
３第１メカニカルシール
４第２メカニカルシール
７回転密封環（第１メカニカルシール）
１１静止密封環（第１メカニカルシール）
１２スプリング（第１メカニカルシール）
１５回転密封環（第２メカニカルシール）
１７静止密封環（第２メカニカルシール）
１８スプリング（第２メカニカルシール）
２２供給ポート
２３第１絞り部
２５第２絞り部
Ａ被密封流体領域
Ｂパージガスの排出領域
Ｃ大気領域 1-shaft seal casing 2 rotating shaft 3 first mechanical seal 4 second mechanical seal 7 rotating seal ring (first mechanical seal)
11 stationary seal ring (first mechanical seal)
12 spring (first mechanical seal)
15 rotation seal ring (second mechanical seal)
17 stationary seal ring (second mechanical seal)
18 spring (second mechanical seal)
22 Supply port 23 1st restrictor 25 Second restrictor A Sealed fluid area B Purge gas discharge area C Atmosphere area

Claims (4)

回転機器の機内領域と機外領域とを区画する軸封部ケーシングと、この軸封部ケーシングを洞貫する回転軸との間に、当該回転軸の軸線方向に並列する、機内側の第１メカニカルシール及び機外側の第２メカニカルシールが配置されているタンデム型ドライコンタクト軸封装置であって、
前記第１及び第２メカニカルシールは、それぞれ、前記回転軸に設けられた回転密封環と、前記軸封部ケーシングに設けられた静止密封環と、一方の密封環を他方の密封環へと押圧付勢するスプリングとを備えており、
前記第２メカニカルシールの静止密封環の背部には、当該静止密封環の背面にパージガスを供給する複数の供給ポートが周方向に所定間隔で配設されており、
前記第２メカニカルシールの静止密封環は、この静止密封環の背部領域と、当該静止密封環の密封端面に形成された環状凹溝とを連通する連通路を有しており、且つ
前記パージガスが供給される第２メカニカルシールの静止密封環の背部領域と、当該第２メカニカルシールの静止密封環の密封端面の外周外方領域とを連通する流路に第１絞り部が形成されていることを特徴とするタンデム型ドライコンタクト軸封装置。 A first on the inside of the machine, which is parallel to the axial direction of the rotary shaft, between a shaft seal casing that divides the in-machine region and the outside region of the rotary device and a rotary shaft that penetrates the shaft seal casing. A tandem dry contact shaft seal device in which a mechanical seal and a second mechanical seal outside the machine are arranged,
The first mechanical seal and the second mechanical seal respectively press a rotary seal ring provided on the rotary shaft, a stationary seal ring provided on the shaft seal casing, and one seal ring to the other seal ring. With a spring to bias,
A plurality of supply ports for supplying purge gas to the back surface of the stationary sealing ring are arranged at predetermined intervals in the circumferential direction on the back of the stationary sealing ring of the second mechanical seal.
The stationary sealing ring of the second mechanical seal has a communication path that communicates the back region of the stationary sealing ring and an annular groove formed in the sealing end surface of the stationary sealing ring, and the purge gas is The first throttle portion is formed in a flow path that communicates the back region of the stationary seal ring of the second mechanical seal to be supplied and the outer peripheral region of the sealing end surface of the stationary seal ring of the second mechanical seal. A tandem type dry contact shaft seal device. 前記第２メカニカルシールの静止密封環の密封端面の外周外方領域と、当該第２メカニカルシールの回転密封環の背部領域であって前記パージガスの排出口が開口している領域とを連通する流路に第２絞り部が形成されている請求項１に記載のタンデム型ドライコンタクト軸封装置。   A flow that communicates between the outer peripheral outer region of the sealing end surface of the stationary sealing ring of the second mechanical seal and the region that is the back region of the rotary sealing ring of the second mechanical seal and that is open to the purge gas discharge port. The tandem dry contact shaft seal device according to claim 1, wherein a second throttle portion is formed in the path. 前記パージガスの供給路が前記軸封部ケーシングに形成されており、この供給路に連通するように環状のガスヘッダーが当該軸封部ケーシングの内周部に設けられており、且つ、前記ガスヘッダーが、前記供給路に連通して接続される広路と、この広路と連通しており、当該広路よりも前記回転軸を基準とした半径方向の寸法が小さい狭路とで構成されている請求項１〜２のいずれかに記載のタンデム型ドライコンタクト軸封装置。   The purge gas supply path is formed in the shaft seal casing, and an annular gas header is provided on the inner periphery of the shaft seal casing so as to communicate with the supply path, and the gas header However, it is constituted by a wide road connected in communication with the supply path, and a narrow road communicating with the wide road and having a smaller radial dimension with respect to the rotation axis than the wide road. The tandem dry contact shaft seal device according to any one of claims 1 and 2. 前記環状のガスヘッダーが、前記軸封部ケーシングの内周面に形成された環状の深溝と、この深溝と並設された環状の浅溝と、両溝を覆うように前記軸封部ケーシングの内周面に当接して固定された短円筒体とで形成されており、且つ、前記短円筒体における、前記浅溝を覆う部分にパージガスを供給する複数の供給ポートが形成されている請求項３に記載のタンデム型ドライコンタクト軸封装置。   The annular gas header includes an annular deep groove formed in an inner peripheral surface of the shaft seal casing, an annular shallow groove arranged in parallel with the deep groove, and the shaft seal casing so as to cover both grooves. And a plurality of supply ports for supplying purge gas to a portion of the short cylinder that covers the shallow groove. 4. The tandem dry contact shaft seal device according to 3.
JP2004266756A 2004-09-14 2004-09-14 Tandem dry contact shaft seal device Active JP4000324B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2004266756A JP4000324B2 (en) 2004-09-14 2004-09-14 Tandem dry contact shaft seal device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2004266756A JP4000324B2 (en) 2004-09-14 2004-09-14 Tandem dry contact shaft seal device

Publications (2)

Publication Number Publication Date
JP2006083889A true JP2006083889A (en) 2006-03-30
JP4000324B2 JP4000324B2 (en) 2007-10-31

Family

ID=36162570

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2004266756A Active JP4000324B2 (en) 2004-09-14 2004-09-14 Tandem dry contact shaft seal device

Country Status (1)

Country Link
JP (1) JP4000324B2 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009066664A1 (en) 2007-11-20 2009-05-28 Eagle Industry Co., Ltd. Mechanical seal and tandem seal
EP2169282A1 (en) * 2008-09-25 2010-03-31 Siemens Aktiengesellschaft Assembly with a shaft seal
JP2010209937A (en) * 2009-03-06 2010-09-24 Nippon Pillar Packing Co Ltd Contact type mechanical seal
WO2011135016A1 (en) * 2010-04-30 2011-11-03 Siemens Aktiengesellschaft Assembly comprising a shaft seal
DE102014218937A1 (en) 2014-09-19 2016-03-24 Siemens Aktiengesellschaft Shaft seal, method of operation
CN107747630A (en) * 2017-09-27 2018-03-02 当涂县金龙机械有限公司 A kind of squeezer bearing shell sealing structure
JP2021081021A (en) * 2019-11-21 2021-05-27 日本ピラー工業株式会社 Shaft sealing device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105757256A (en) * 2016-04-26 2016-07-13 成都通密封股份有限公司 Dry-gas sealing device for can-type three-in-one equipment

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5372772B2 (en) * 2007-11-20 2013-12-18 イーグル工業株式会社 Tandem seal
WO2009066664A1 (en) 2007-11-20 2009-05-28 Eagle Industry Co., Ltd. Mechanical seal and tandem seal
US20100270749A1 (en) * 2007-11-20 2010-10-28 Eagle Industry Co., Ltd. Mechanical seal device and tandem seal device
US8585060B2 (en) 2007-11-20 2013-11-19 Eagle Industry Co., Ltd. Tandem seal device
EP2169282A1 (en) * 2008-09-25 2010-03-31 Siemens Aktiengesellschaft Assembly with a shaft seal
WO2010034601A1 (en) 2008-09-25 2010-04-01 Siemens Aktiengesellschaft Arrangement comprising a shaft seal
WO2010034605A1 (en) * 2008-09-25 2010-04-01 Siemens Aktiengesellschaft Arrangement comprising a shaft seal
US8714907B2 (en) 2008-09-25 2014-05-06 Siemens Aktiengesellschaft Arrangement comprising a shaft seal
US8647052B2 (en) 2008-09-25 2014-02-11 Siemens Aktiengesellschaft Arrangement comprising a shaft seal
JP2010209937A (en) * 2009-03-06 2010-09-24 Nippon Pillar Packing Co Ltd Contact type mechanical seal
CN102869907A (en) * 2010-04-30 2013-01-09 西门子公司 Assembly comprising a shaft seal
WO2011135016A1 (en) * 2010-04-30 2011-11-03 Siemens Aktiengesellschaft Assembly comprising a shaft seal
RU2560971C2 (en) * 2010-04-30 2015-08-20 Сименс Акциенгезелльшафт System including shaft seal
US9341077B2 (en) 2010-04-30 2016-05-17 Siemens Aktiengesellschaft Assembly comprising a shaft seal
DE102014218937A1 (en) 2014-09-19 2016-03-24 Siemens Aktiengesellschaft Shaft seal, method of operation
CN107747630A (en) * 2017-09-27 2018-03-02 当涂县金龙机械有限公司 A kind of squeezer bearing shell sealing structure
JP2021081021A (en) * 2019-11-21 2021-05-27 日本ピラー工業株式会社 Shaft sealing device
JP7291064B2 (en) 2019-11-21 2023-06-14 日本ピラー工業株式会社 Shaft seal device

Also Published As

Publication number Publication date
JP4000324B2 (en) 2007-10-31

Similar Documents

Publication Publication Date Title
JP7214722B2 (en) Seal ring
JP5367423B2 (en) Sealing device
CN112088266B (en) Sealing ring
JP4763920B2 (en) Multistage shaft seal device
WO2020196145A1 (en) Sliding component
CN111033066B (en) Sliding component
CN112334690B (en) Sliding assembly
KR940007405A (en) Seal array spiral seal system and how to seal against leaks in processing fluid
EP2233802B1 (en) Shaft-seal device for a high-speed rotation apparatus
JPWO2009066664A1 (en) Mechanical seal and tandem seal
GB2216964A (en) Rotating shaft seal
JP4000324B2 (en) Tandem dry contact shaft seal device
US6761359B2 (en) Spacing element for centering components in a mechanical seal and for promoting circulation of a seal fluid therein
JP4001594B2 (en) Tandem dry contact shaft seal device
JP2003074712A (en) Mechanical seal device
JP2903459B2 (en) Shaft sealing device for pump
JP3008013B2 (en) Shaft sealing device for fluid equipment
JP2003227570A (en) Shaft sealing device
US5368313A (en) Bushing for trapped bushing seal
JP6002537B2 (en) Shaft seal device
JP2001074225A (en) Regenerative treating device
JP2001140888A (en) Bearing device and turbocharger provided therewith
JP6863857B2 (en) Shaft sealing device
JP2005249007A (en) Rotary joint
JP2023135955A (en) mechanical seal

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20070628

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20070724

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20070813

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

Ref document number: 4000324

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100817

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100817

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110817

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110817

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120817

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120817

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130817

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140817

Year of fee payment: 7