GB2173265A

GB2173265A - An adjustable sealing apparatus for a rotation shaft and an auto-circulating lubrication system therefor

Info

Publication number: GB2173265A
Application number: GB08531207A
Authority: GB
Inventors: Huang Yongguan
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-04-01
Filing date: 1985-12-18
Publication date: 1986-10-08
Also published as: DE3605883A1; JPS61236970A; GB8531207D0; DE3605883C2; GB2173265B; CN85101501A; CN85101501B

Abstract

A sealing apparatus for a rotating shaft extending through a housing comprises a running seal ring (7) which carries out radial and axial seals simultaneously, and an adjustable compression spring (9) sleeved on the shaft, which presses the running seal ring against stationary seal ring 6. An auto-circulating lubrication system for said sealing apparatus without oil pump and circulator is used to circulate the lubricant within the system whether the shaft is running clockwise or counterclockwise. <IMAGE>

Description

SPECIFICATION An adjustable sealing apparatus for a rotation shaft and an auto-circulating lubricating system therefor The present invention relates to an adjustable sealing aparatus for rotation shaft and an autocirclutating lubrication system therefor suitable for axial and radial seals.

It is well known that the sealing apparatus plays an important role in various kinds of shaft, and the conventional sealing apparatus can, to certain extent, well perform in seal of the shaft running in general working condition. There exists, however, a common defect in such conventional sealing apparatus of losing efficacy before its service life when it works in adverse working condition, which not only increses the maintenance cost, but also leads to leakage and contamination, even the serious accident, such as stopping work.

For example, a kind of rotation shaft sealing apparatus is disclosed in US Patent No.

41,391,450, in which a stationary seal ring is pressed toward to a running seal ring by a coil spring, as shown in Fig. 1 of the specification, so that a axial seal face with tight contact is formed between a running seal ring and a stationary seal ring. The radial seal is performed by using an "0" type ring seal in order to permit the stationary seal ring to move along the shaft slightly. It is apparent that such kind of sealing apparatus has a defect that, because a stationary seal ring must be fixed by an "0" type seal ring and movable pins (keys) on the housing unmovable relative to the rotation shaft, the range of adjustment is limited thereby.Furthermore, in practice operation, the radial uncentering and subsiding of the rotation shaft, particularly, of the shaft with cantilever bearing is not avoidable so that there is a possibility of shaft wearing and stationary seal ring rotating with the shaft due to only the tiny clearance existing between a stationary seal ring and the rotation shaft. Such radial uncentering and subsiding of the rotation shaft will cause the "0" type radial seal ring to be contracted irregularly and to be worn away rapidly when the stationary seal ring rotates with the rotation shaft, the radial seal of the sealing apparatus will lose its effectiveness much quickly.At the same time, it is also apparent that it is quite difficult for said "0" type seal ring to either ensure a stationary seal ring to slide along the shaft slightly or ensure the reliable radial seal, because the interference between the "0" type seal and the rotation shaft is not easy to control when the said seal ring is being fixed on the shaft. Particularly, when the sealing apparatus has been used for certain period, this interference can not ensured perfectly. Additionally, it can be seen that, since the axial thickness of the stationary seal ring is requested to be increased in order to fix the "0" type seal ring and remain a certain dimention for guide portion, the size of whole seal apparatus must be increased apparently.Furthermore, if such sealing apparatus is used in water containing sand, the wear of sealing face is also greatly increased as water comes into the said sealing face.

Another kind of mechanical rotation shaft sealing apparatus is also disclosed in US Patent No 4,463, 958, in which the stationary seal ring is directly fied on the housing and a running seal ring which is sleeved on the shaft carries out both axial and radial seal simultaneously. In order to overcome the defects abovementioned a coil spring sleeved on the shaft causes a running seal ring to rotate by means of a thrust ring. However, such radial seal is not reliable when the running seal ring rotates because it is difficult for thrust ring to rotate the "0" portion of said running seal ring only by means of the contact therebetween. It can be seen that the running seal ring is liable to deform when the coil spring is pressed thereon, so that the sealing element is no longer workable.Moreover, when lubricant under pressure enters into the chamber formed by running seal ring and rotation shaft, the pressure force of lubricant will intend to resist the pressure force applied to "0" portion of running seal ring by thrust ring and the seal will be entirely unworkable when the pressure of lubricant is sufficiantly high. It can be observed that, since there is a large clearance between the inner wall of running seal ring and the shaft except at "0" portion and there is no shoulder for stopping, the running seal ring will move alternatively thereby the abnormal wear and the leakage of lubricant on sealing face is unavoidable.

The structure of sealing apparatus according to this invention is substantially different from the conventional sealing apparatus. Not only can it keep effective seal in various circumstances, but also no special workman is needed for management and reparation when in service. Therefore, the present invention overcomes the abovementioned defect relating to conventional sealing apparatus rationally so that the seal of the rotation shaft is effected.

The sealing apparatus according to this invention characterized by: using at least one elastic seal ring having a sufficient sectional area to carry out simultaneously sealing in both radial and axial directions; using a compression sring to adjustably press and drive the seal ring, so as to bring the seal ring into contact with the shaft and to keep the sufficient specific pressure at any time in order to remain the seal of end face; at least one helical grooves on the inner wall of bearing which supports the shaft, or on the surface of the shaft itself, as the lubricant passage which enables the lubricant automatically to be circulated when the shaft is running.

Object of the invention; The object of the invention is to provide a sealing apparatus for rotation shaft which is lubricated and cooled by oil or water without the defect of the abovementioned conventional sealing apparatus; The another object of the invention is to provide a sealing apparatus for rotation shaft wherein the specific pressure of seal surface can be compensated automatically or adjusted manually easilly when the sealed end face is under being worn; Still another object of the invention is to provide a sealing apparatus for rotation shaft which has long service life, simple construction, perfect seal effectiveness and has no phenomena of drip, ooze and leakage of lubricant, and which is easy for adjustment, suitable for emergency use and low initial cost, and which can be used in various working conditions without management needed in service.

The further object of the invention is to provide an auto-circulating lubrication system for the sealing apparatus according to the invention to improve the working condition of the working faces of the sealing parts and the bearings, in which the lubricant can be circulated, filtered, settled and cooled automatically without oil pump and circulator.

The principle and construction of the said sealing apparatus according to the present invention will be explained in detail herebelow by taking a stern shafting as an example because the seal of a stern shafting which works in very adverse circumstances as the ship is navigated in different water areas is extermely difficult in comparison with the other kind of shafting.

In marine shafting, the sealing apparatus of stern tube bearing is used to seal the water and the oil.

Its reliability will directly effect on the operation efficiency of the ship. The marine stern tube bering is devided into two groups, i.e. open type and close type. In general, the open type stern tube bearing using water as lubricant and coolant has the features of simple construction, economic operation, no leakage at stern shaft, but when it is used in water area containing much sand, the wear of the stern tube bearing is serious. For the close type stern tube bearing, the oil is used as lubricant and coolant and it can be used for any water area, but one set of reliable sealing arrangement is necessary, otherwise it is difficult to overcome the leakage of the stern shafting.

In the prevailing methods for end face seal, the radial and axial seals are generally carried out by two components, respectively, i.e. a soft compound, such as a rubber ring, is used for radial seal and a hard component, such as a metsal or bakelite ring, is used for axial seal. Thus, the contact between running ring and stationary ring is rigid or semi-rigid. As a result, if the sealing faces are perfectly contacted, the oil film or water film is not so easy to be formed. Therefore, the friction between running ring and stationary ring will be dry friction or semi-dry friction and its service life will be effected sharply thereby. Contrarily, if the sealing faces are not perfectly contacted, the oil (water) will leak out in large quantity. It means that the reasonable range of specific pressure for enabling the seal is very narrow and it is difficult to control and adjust.As the anti-wear performance of some hard material used at present, such as hard alloy, is limited, their service life and sealing ability can not be increased greatly. Moreover, in traditional end face sealing a fork or key mounted on the shaft is specially used for driving the running ring. If the running ring is worn seriously or the key is fitted unproperly, it will be disengaged from the fork or the key and the serious leakage will occur accordingly. Since the auto-circulation of lubricant has not been realized properly, the lubrication of sealing elements in conventional sealing apparatus goes from bad to worse.This will speed up the wears occurred on the contact faces between sealing rings and on the shaft or bearing: The present inventjion will be described in great detail with the preferred embodiments of sealing apparatus according to the present invention referring paning drawings, in which: Figure 1 is a cross section view of the first embodiment of sealing apparatus according to this invention; Figure 2 is a cross section view of the second embodiment of sealing apparatus accordingthis invention; Figure 3 is a cross section view of the third embodiment of sealing apparatus according to this invention; Figure 4 is a cross section view of the fourth embodiment of sealing apparatus according to this invention; Figure 5 is a cross section view of the fifth embodiment of sealing apparatus according to this invention; ; Figure 6 is a schematic view of auto-circulating lubrication system according to this invention.

Detailed description of the present invention Referring to Fig. 1, the sealing apparatus is divided into two parts which are located on the two ends of the stern tube, respectively. The principle of these two parts is substantially the same, but the structures are slightly different. The inboard part of the sealing apparatus which is located on the stern tube tank within the vessel (briefly called "inboard part" hereinafter), consists of ring (7) which has a sufficient thickness and is made of oil-proof and wear-resistant material, such as oil-proof and wear-resistant rubber, as running seal ring (briefly called "running ring" hereinafter), a cylindrical pressure sping (9) provided for pushing a runing tube (7) towards a stationary seal ring (6) (briefly called "stationary ring" hereinafter) and another sealing component (11) sleeved on the stern shaft.The interference fit between running ring (7) and the strern shaft is obtained for getting the radial stationary seal. With the pressure spring tray (10) and running ring tray (8), running ring (7) is pushed by compression spring (9) towards the friction face of the stationary ring to get the axial seal of stern shaft. The stationary sealing component (12) is a hollow plug which has at least one annular groove provided for fitting "0" type sealing ring (11) on the outer surface of plug, and which has at least one groove on the inner surface of the plug winding in the same direction as that of rotation of the stern shaft rotating clockwise, and the plug, stationary sealing component (12), stationary ring (6) and running ring (7) define a sealing chamber.The stationary ring (6) and stationary selaing component (12) are connected to the stern shaft tube by at least two bolts so as to carry out a complete seal. In order to ensure the auto-circulation of lubricant, there is at least one helical groove on the inner surface of stern tube bearing. The helical grooves together with the ahead oil supply pipe of statiuonary ring, the sealing chamber, hollow plug (12), the ahead oil return pipe of stern tube constitute and autocirculating lubrication system, which will be described in detail later referring to Fig. 6.

The bead of running ring tray is pressed to the outer circumference of running ring in order to ensure the shrink force to fit the running ring on the stern shaft and to keep it maintaining antipressed so that the shrinkage in size and oil lakage due to oil immerssion all year round and aging can be avoided. Compression spring tray (10) is fitted on the stern shaft. There is a key slot on pressure spring tray (10) and running ring tray (8). A square key located on the outside of each end of spring (9) is put into the said slot. The side clarance of key is rather big, the shaft not only can move backwards and forwards freely in axial direction, but also can make some slidings between running ring (7) and stern shaft to prevent the sticking which may occur due to no sliding between running ring (7) and stern shaft for a long time.When the stern shaft shifts in axial direction or for some reasons, running ring (7) can move backwards and forwards in axial direction in time by means of spring (9) and contact closely with the anti-friction face of the stationary ring, so as to keep a good sealing condition.

In order to keep free sliding of running ring on stern shaft and maintain a good radial seal as well, one or more ring grooves may be made at the inner face of running ring.

Stationary ring (6) is made of wear-resistant hard material. An antiwear material is inlaid on the sealing face of running ring (7). It is effective to overcome over-wearing of rings occerred during the initial operation due to very high pressure or unfinished sealing face. Since the sealing face has a certain self-lubricating ability, the effective seal can be carried out by the seling ring without any over-wearing. During operation, the stationary ring made of hard material is polished by the running ring, therefore, a mirror finish will emerge in the sealing face of stationary ring within a certain period after operation.

For increasing sealing reliability, a set of stand-by sealing arrangement is also used, which consists of running sealing ring (5) and its. fixing and adjusting parts (2), (3), (4). When the stern shaft shifts in axial direction, the said stand-by sealing arrangement will increase sealing ability and be of stopping function.

Bolts (13) are not only to connect stationary ring (6) and hollow plug (12) to the stern tube, but also to move stationary ring (6) in axial direction by adjusting bolts (13), so as to adjust the specific pressure between running ring (7) and the anti-friction face of stationary ring (6) and to get optimum sealing result.

The structure of the seal located at the outboard end (briefly called "outboard seal" here-inafter) is substantially the same as the structure above-mentioned. The sealing chamber is formed through the contact between running rings (15), (19) and the anti-friction faces of stationary rings (14), (20). In the sealing chamber, the lubrication is carried out by grease. In the same way, there is stand-by sealing ring (21) located between the outside of stationary ring (20) and the propeller for improving sealing ability.

The apparatus of the first embodiment has the feature of simple structure and easy for adjusting. Furthermore, by increasing or reducing the number of the number of gaskets (1) of the coupling, adjusting the thrust bearing within the tank and changing the axial displacement of stern shaft, the sealing condition of sealing face will be adjustable. At the same time, the specific pressure of antifriction face of running ring (7) and stationary ring (6) can be adjusted separately by adjustable bolts (13). Moreover, the auto-circulating lubrication system which will be described later can be used.

The 2nd embodiment according to this invention will be described referring to Fig. 2, it is very clear that the principle and structure are completely the same as 1st embodiment above mentioned. The only difference is that at the inboard sealing end there is no stand-by ring (5) and fixing parts (2), (3), (4) and statioary ring sleeve (37) is fitted on the stern tube only. The hollow plug is fitted adjustably on the stationary ring sleeve and on the sealing face there is at least one annular groove ring for filling the anti-wear material as a stationary ring (6) which contacts with two rings (7). The specific pressure of the contact face between running ring, (7) and hollow plug (stationary ring) (6) can be adjusted by adjusting bolts (38).The shrink fore acted on the stern shaft by the running ring is stabilized through the running ring tray pressed by spring as inner conical surface. At the portion of tray sleeved on the stern shaft, there is at least a through groove for slide fit with the key of stern shaft to ensure that compression spring (9) rotates together with running seal ring (7). Two running ring (18, 19) of the outboard seal and stationary ring (20) constitute the contact sealing surface. The inboard seal and the outboard seal are communicated through the helical groove of stern tube bearing. At the same time, it is lubricated by auto-circulating lubrication system.

In this embodiment, the axial displacement of stern shaft can be changed by increasing or decreasing the number of gaskets (1) of coupling (35) for adjusting the sealing condition of each sealing surface, just as same as shown in 1st embodiment. The specific pressure of contact surface between running seal ring and hollow plug (stationary ring) can be adjusted separately by adjusting bolt (38). Moreover, the outboard seal of stern tube also can be lubricated by the auto-circulating lubrication system.

The 3rd and 4th embodiments of this invention will be described in detail by reference to Fig.

3 and Fig. 4. The 3rd and 4th embodiments are simple construction type. They have no adjusting part located on front of the inboard stationary seal ring, the stand-by ring and the gap seal located on front end face of the propeller and its water-proof rubber ring, the running ring of outboard seal ring is sticked reversely on the stationary ring. Its adjusting method is the same as that of the 1st embodiment, i.e. by increasing or decreasing gaskets (1) of coupling (35) and adjusting the thrust bearing to move the stern shaft backwards for pressing tightly the outboard seal and to move the inboard seal separately for adjusting the specific pressure of sealing face.

Their service performances are satisfactory, even if it is wound by fishing net, the out-board seal also could not be damaged. They have advantages of simple construction, lower cost of production (lower than that of 1st embodiment), to it is more suitable to be used on medium and small ships. In the 4th embodiment the stationary rings of inboard and outboard seals are dismoutable, therefore it is easy to be made separately and to select proper material of the stationary ring which is light and has a good thermal conductivity. It is also easy to inspect the wear of seal ring. However, it is also suitable for large stern shaft.

The 5th embodiment of this invention will be described refering to Fig. 5. In this embodiment, only the inboard seal is different. Running ring (7) is contacted by friction with the front face of stationary ring (6) fitted on the stern tube to form sealing face. Compression spring (9) which is sleeved on the stern shaft is pressed on running ring (7) by means of trays (8), (10). At the end adjacent coupling (35), a supporting flange (3) with regulator (such as adjusting screw) is fitted.

The specific pressure of contact surface between running ring (7) and stationary ring (6) can be regulated separately by adjusting screw (2).

The features of the installation described in the 5th embodiment are as follows: simple structure; The wear and seal condition of the sealing end face can be inspected directly since the complete set of seal is open type.

Easy to adjust, When increasing or dereasing the number of gaskets (1) of coupling (35) and adjusting the thrust bearing to move the stern shaft in axial direction, the specific pressure of stern shaft sealing face at both inboard and outboard and outboard can be regulated simultaneously and there are no needs to regulate separately; In the 6th embodiment of this invention (no Figure), the stationary rings including sleeves of each embodiment as shown in Fig. 1 to 5 are designed in half-ring type in order to install and inspect the wear condition of each sealing face easily. Frome the technical point of view, it is more important for large ships.

Fig. 6 is a schematic drawing of auto-circulating lubrication system for the sealing apparatus of this invention. As shown in Fig. 6, it can be seen that it is the first time that the oil pump and circulator are cancelled in the auto-circulating lubrication system. When the ship is sailing the auto-circuit of lubricant is carried out by stern shaft rotation and pulsation. The auto-circulting lubrication system consists of a circulating oil tank (51), an ahead oil supply pipe (53) with filter net on the inlet which is higher than and the bottom of circulating tank (51) with a height H. The auto-circulating system also consists of an ahead return oil pipe (58) without filter net on the corresponding inlet which is also higher than the bottom of the circulating tank (51) is h. On ahead oil supply pipe (53) there is a check valve (56) and on ahead return oil pipe (58) there is also a check valve (57). A flow speed and flow capacity meter (54) can be installed on ahead oil supply pipe (53), if necessary. There is a pipe (52) controlled by a cock (55) for measuring the oil level and the leakage, which is located between the outlet of check valve (56) and the top of circulating tank (51) in order to check the oil leakage of each sealing surface easily.

The ahead oil supply pipe of auto-circulating lubrication system is inserted into the sealing chamber of inboard seal on stern shaft through a connecting member and it links up with an ahead oil return pipe through the helical grooves of hollow plug (12), the stern tube bearing and the sealing chamber of stern shaft outboard seal (as shown in Fig. 2, Fig. 3, Fig. 4, and Fig. 5) or directly links up with an ahead oil return pipe (as shown in Fig. 1). Therefor, whether the ship goes ahead or astern, the lubricant always can circulate automatically due to those helical grooves. The only difference is the direction of flow. After opening cock (55), closing check valve (56), (57), it can be found that the leakage condition of the seal surface in this system from the level variation of liquid indicating tube (52) made of transparent nylon.

In the sealing apparatus according to this invention shown in Fig. 2-5, the lubricant pressure is forced from the back face of both inboard and outboard runnign rings, so that the specific pressure of sealing ring can be regulated by changing the height of oil tank or by using another pressing means instead of moveing the stern shaft. This regulating method not only is simple and easy, but also can ensure the uniformity of specific pressure round the sealing ring. By this way, the stern shaft adjusting interval will be much longer and the adjusting times will be decreased which must move the stern shaft when such adjustment is done.

This invention solves fairly completely the leakage of stern shaft seal and the auto-circulating lubrication. It also has the advantages of simple structure, long service life, lower consumption of power, no maintenance needed, easily inspecting and adusting etc. Furthermore, when the seal apparatus is installed, it is unnecessary to change the structure of original shafting so that the cost is lower than the traditional stern shaft sealing apparsatus. It, through measuring , is proved that when the used lubricant is employed as lubricant of the seal, the specified lubricant consumption is about 20 g/1000HP. hr and can be adjusted. The weardown comes near the natural wear rate basically.The stern shaft seal and its bearing can be used about 70,000 hrs without dock repair, due to the friction resistance of seal is very low, the power consumption of seal is about 3HP when it is used on a 10,000 HP ocean-going ship. Therefore, the seal can be used normally under the severe service condition, such as in deep water, in water containing sand or when the stern shaft shifts in axial direction moves up and down and is uncentering and subsiding in a large range. When using it, under the condition abovementioned, the ship type and the water area are not limited. Its endurance and suitability are good.When the outboard seal is damaged for some causes, the oil circulation will be stopped, the emergency performance of sealing arrangement is also very reliable as long as supplying lubricant at regular intervals and in a fixed quantity to a ship evigating in a long voyage until yard repair. Of course, it is based on the inboard seal (including piping) being in a good condition.

Table 1 is a table of economic benefit comparison. This table shows that this invention has got a benefit of RMB Y 32,750 in first year after deducting the refitting cost of RMB 1,5000.

When using this new sealing apparatus on a middle size passenger/cargo ship (500 HP, 600 seats, 5000 GRT) sailing in diameter of stern shaft is 110 mm. Two shafts and two propellers are installed.

From the table, it can be known that the economic benefit and the social benefit of shaft sealing apparatus described in this invention is remarkable while the water pollution is prevented effectively. Besides, this sealing apparatus also can be used for sealing the rotation shaft of the other machineries.

Although the descriptions of adjustable rotation shaft sealing apparatus and its auto-circulating lubrication system of this invention above mentioned are based on the said 5 embodiments, it should be understood that this invention is not limited to the ranges above mentioned. Any modification and improvement based on this invention made by the person skilled in the art should be considered as within the spirit and scope of what is claimed herein-below. COMPARISION OF ANNUAL MAJOR ECONOMIC TARGETS OF THE TESTINO SHIP BEFORE AND AFTER MODIFICATION

h w X o o u 1,0 comsup. fl consump. Repair v Suspension loss MannemA,nt h dification I . cost C . > - RMB Times Cost 1),s 9 > V V R V ling lube oil each dehan Sefore 4500 9000 145 36250 " 3000 20 20000 ing gland once 8250 15 * $ t::ttion per season I tS X I 1500 After *I rlBC w O 135 33750 o 150 0 No a c, re oco o s, Ce J c lp C b 0 0 0 I on e aw V 8000 e zD 10 t Saving RAIB V 2570%0 1.9 times ffi days e sE V 2850 RI Q O N 2 20000 95,' N -0] Nain tnc)ical Ship type: steel passenger/argo ship . Overall r 52 M, d breadth: S.2 M &num; depth: Load draft: data or the m o a a M fiend hip 8are O passengers, 4OCt cargo; propulsion po't(ir: O HP x w4 Sasic diameter of C ZD Shaft speed: 500 rpm; Sealing type & oil typo before modification: internal seal is .o oi k external seal is turn-in & turn-out type rubber plate type, using X hand pump for oil 8 fication, this o arrangement is o n ~~ N 1. fuel is from | 4 Crieon loss by using the said sealing arrangemant.

2. As shown in the above table, after using the suid sealing arrangement, a avna of Rl V 34,250 is obtained deducing the modification cost of ao c X ,500, The oonomic benifit in t4 C.) X O ~ El 1 r4 ,4 .o C , Y n ~l > h ,4 v a t t4 4' 1 : &commat; o to > z: rs ~ o p 0 4 e Hc p ,4 N O ~ : . o, t4 > , 3 U ~ O $*,4 4n 54 X X ò4 X e 1 4 X 4 De o o o X a Ei a ^ o a > 0 > tzOt & t f04 a t2 n to U > o c * Yc a -o, o O,t b ,4 h o 4 4 o ~ & .4 {1 0o O 4 > C h 0z t g ,4 > 4 4 t to O p a E; B ,t CQt ei a ~ ~ g ho 4 7 > 4 OEI ~ | -4 > g r.tt C > srt to tt ,qt a < E tSr 8 8 xZ 8 - -X4 es t '4 X O ~ O 0bs vo a e 4 9 C a ot a 8 a &commat; eSt, > 4 Q a) tD, 4: > . t4,4 Ot 2 ' a O . 4 4 C 4 &commat; g > hD O O tXl o 4v h 4 4 > O .Y 0 uo t2 f4t t ff ct 4 > t ~ ~~ Be/ t~ rsX - ot ,4 4 / > > ss &commat; C . Et X M R X s

Claims

1. A rotation shaft sealing apparatus having an elastic seal ring carring out both radial and axial seal and a coil spring sleeved on said rotation shaft press the seal face formed by a running seal ring and a stationary seal ring, characterised in that said elastic seal ring is a running seal ring which has two parallel end faces between which the axial distance is smaller than deviation between the outer radius of said seal ring and the radius of said rotation shaft and which is sleeved on said rotation shaft with interference, one of the said end faces being contacted with said stationary seal ring to form a axial seal face tightly, and the other end face being pressed by means of compression spring which has an outer diameter smaller than the diameter of said running seal ring, a spring tray and a running seal ring tray so that the whole running seal ring comes to contact with said stationary seal ring uniformely to form an adjustable selft-tight system, thereby said sealing face being conpensatable when it is being worn.

2. A rotation shaft sealing apparatus according to claim 1, characterized in that the distance between said two parallel end faces is approximately 15-30% of the diameter of said rotation shaft.

3. A rotation shaft sealing apparatus according to claim 1 or 2, characterized in that the antiwear agent is inlaid on the end face formed by a running seal ring and a stationary seal ring when they are contacted.

4. A rotation shaft sealing apparatus according to claim 1 or 2, characterized in that there is at least one annular groove on the inner parietal surface of said running seal ring to permit the axial movement of said running seal ring along the shaft and to enhance radial seal between said running seal ring and the shaft.

5. A rotation shaft sealing apparatus according to claim 1, characterized in that said spring tray and running seal ring tray fixed on the shaft have, respectively, a bead with at least one axial key slot thereon within which the corresponding key on the end face of said spring is received, thereby to rotate the said spring together with the rotation shaft.

6. A rotation shaft sealing apparatus according-to claim 5, characterized in that a second bead extending oppositely from said bead on running seal ring tray is pressed against the outer circumference of said running seal ring to ensure said running seal ring to clip the shaft.

7. A rotation shaft sealing apparatus according to claim 1, characterized in that it is with a inner conical face that said running seal ring tray attaches to said running seal ring so as to ensure said rinning seal ring tray to thrust said running seal ring axially and said running seal ring to clip the shaft radially simultaneously.

8. A rotation shaft sealing apparatus according to Claim 1, characterized in that the tray of running seal ring, compression spring and its tray are sleeved on the roatation shaft and there is provided a fixed supporting flange with regulator on the shaft end adjacent to the compression spring tray, so that the specific pressure of the fricrtion surface between running seal ring and stationary seal ring can be adjusted by the regulator.

9. A rotation shaft sealing apparatus according to Claim 1, characteriaed in that the said stationary seal ring is fixed on the shaft sleeve by at least two adjusting bolts which are used to adjust the specific pressure of friction surface between stationary seal ring and running seal ring.

10. A rotation shaft sealing apparatus according to Claim 9, characterized in that the antiwear agent is inlaid on the end face between stationary seal ring and the running seal ring.

11. A rotation shaft sealing appratus according to Claim 1, characterized in that on the outside of said stationary seal ring, there is a stand-by seal ring to enhance the effects of sealing and limiting.

12. A rotation shaft sealing apparatus according to Claim 1, characterized in that there is at least one helical groove as the passage of lubricant on the inner surface of the bearing of the rotation shaft.

13. A rotation shaft sealing apparatus according to Claim 9, characterized in that the said stationary seal ring is an integral piece type.

14. A rotation shaft sealing apparatus according to Claim 9, characterized in that the end cover of said stationary seal ring is of a dismountable type.

15. A rotation shaft sealing apparatus according to Claim 9, characiterized in that said stationary seal ring is a half ring type.

16. A rotation shaft sealing apparatus according to Claim 1, characterized in that at least one set of said sealing apparatus is mounted on the sealing end of the shaft.

17. A rotation shaft sealing apparatus according to Claim 1, characterized in that the specific pressure of the seal end faces can be regulated by adjusting the axial displacement of the shaft.

18. An auto-circulating lubrication system used in said rotation shaft sealing apparatus having circulating lubricant tank, oil supply pipe, oil return pipe and check valve, characterized in that no circulating oil pump and circulation is needed and the auto-circulating circuit is formed by the said oil supple pipe, oil return pipe and the rotation shaft sealing apparatus.

19. An auto-circulating lubrication system according to Claim 18 characterized in that there is an altitude difference between the inlet of the oil supple pipe and the bottom of the circulating oil tank, and a filter is fitted as well, and in the same way, there is an altitude difference between the inlet of the oil return Dine and the bottom of the circulatina oil tank.

20. An auto-circulting lubrication system according to Claim 18, characterized in that the said oil supply pipe comes into the sealing chamber of said rotation shaft sealing apparatus through the stationary seal ring located on the end of the shaft.

21. An auto-circulating lubricantion system according to Claim 18, characterized in that the said oil return pipe is connected with oil supply passage through the helical groove of the bearing.

22. An auto-circulating lubrication system according to Claim 18, charzcterized in that for measuring the leakage quantity, a transparent tube with a cock is mounted on the check valve of the oil supply pipe, and the top of the measuring tube should be higher than the highest oil level in circulating oil tank.

23. An auto-circulating lubrication system according to Claim 18, characterized in that the said circulating oil tank is movable and the back pressure of elastic running seal ring can be regulated by adjusting the altitude of the circulating oil tank in order to adjust the specific pressure of the friction surface between elastic seal ring and stationary seal ring.

24. A rotation shaft sealing apparatus substantially as herein described with reference to the accompanying drawings.