JPH086818B2 - Seal for rotating shaft - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a rotating shaft for sealing a liquid medium against a gaseous medium, and more particularly to a stern tube of a ship, the shaft comprising: Or at least one radially extending main lip packing arranged around the shaft bush and sealingly contacting the shaft or the shaft bush, and arranged around the shaft or shaft bush, the contact edge of which in normal operation is The invention relates to a sealing arrangement with at least one radially extending spare lip packing which is located away from the shaft or shaft bushing but whose contact edge is in pressure contact with the shaft or shaft bushing in the event of failure of the main lip packing.

2. Description of the Related Art As a conventional sealing structure of this type, for example, there is one described in German Patent No. 202842. In this sealing structure, the support member holding all the radially extending lip packings including the radially extending spare packing is axially moved with respect to the shaft or the shaft bush arranged so as not to be displaced in the axial direction. It is either movable or the support member is arranged so as not to be displaced axially so that the shaft or bush can move axially. For this reason, the contact edges of the packing are lifted or spaced from the shaft or bush surface. In any of these cases, the auxiliary lip packing is separated from the shaft upper surface or the bush upper surface at one end position of the axial movement and comes into contact with the shaft upper surface or the bush upper surface at the other end position. There is.

SUMMARY OF THE INVENTION This arrangement has the disadvantage that it requires a great deal of manufacturing costs and that in many cases the operational safety of the spare lip packing cannot be achieved to justify the cost.

Therefore, an object of the present invention is to provide a spare lip packing that extends in the radial direction and that can be manufactured at a lower cost in order to eliminate such drawbacks.

Means for Solving the Problem and Its Action In order to solve the above problems, according to the present invention, there is provided a seal structure for a rotating shaft for sealing a liquid medium against a gaseous medium, the shaft or At least one radially extending main lip packing disposed around the shaft bush and sealingly contacting the shaft or the shaft bush, and disposed around the shaft or shaft bush, the contact edge of which in normal operation is the shaft or At least one of two positions, a first position away from the shaft bushing and a second position in which the contact edge is pressed against the shaft or shaft bushing to seal the shaft or shaft bushing in the event of failure of the main lip packing. An elastically deformable hollow core that extends radially. With lip packing
In a seal structure having a pressure line connected to the cavity of the auxiliary lip packing and moving the auxiliary lip packing from the first position to the second position by introducing the pressurized medium into the cavity, the pressurized medium is pressurized water. The preliminary lip packing is formed with a plurality of holes communicating from the cavity to the space on the gaseous medium side, and the openings of the holes are circumferentially distributed in the vicinity of the contact edge of the preliminary lip packing. A seal structure for the characteristic rotating shaft is constructed.

A hollow ring-shaped radially extending lip packing for a shaft or a shaft bush is already known (German Published Patent No. 2606813 and French Published Patent No. 2315045), but this lip packing has a radius relative to the main lip packing. It is not a directional spare lip packing, but rather a primary lip packing for devices that only require temporary shaft sealing.

It is obvious that the manufacturing cost can be reduced by using the hollow ring-shaped lip packing extending in the radial direction. This is because this lip packing consists only of an elastically deformable hollow ring connected to the compression source via the pressure line and the control.

According to a preferred embodiment of the invention, grooves are formed circumferentially in the respective areas of the openings of the holes of the auxiliary lip packing, so that the water flowing out of the holes is hydrodynamically brought into contact with the contact edges. It is sent in the direction to go. By intentionally leaking the pressurized water slightly in this way, the preliminary lip packing is lubricated with the pressurized water.

According to another preferred embodiment of the invention, the rotating shaft comprises the stern tube of the ship, such that the external water is sealed against the air, and the two main lip packings are axial in the shaft. The secondary lip packing is arranged to face the external water, and the auxiliary lip packing is arranged to face the external water in front of the main lip packing.

According to yet another preferred embodiment of the present invention, a spare lip packing is provided for each of the main lip packings.

According to a further preferred embodiment of the invention, the pressure exerted on the contact edge of the spare lip packing is adjustable.

Also, a slide ring packing can be used instead of the radial lip packing.

Embodiment FIG. 1 is an axial sectional view showing a seal structure according to the present invention applied to a stern tube of a ship. In FIG. 1, a bush (2) is arranged around the screw shaft (1). The shaft (1) is supported by a bearing (not shown), and the bearing is supported by a mounting member (3). A seal housing (4) surrounding the outside of the bush (2) is fixed.

The housings (4) are arranged side by side in the axial direction in close contact with each other, and the housings (4.1), (4.2), (4.
It consists of 3) and (4.4). Between the adjacent housing rings of the three housing rings (4.2), (4.3) and (4.4) from the bow, the main lip packings (5.1) and (5.2) extending in the radial direction are respectively sandwiched, and the bushes are held. It is placed around (2). Further, the housing ring (4.1) closest to the stern directly surrounds the outer side of the shaft (1), and the spare lip packing (6) is provided in the inner recess of the housing ring (4.1) which is open toward the shaft. Is attached,
It is arranged around the shaft (1).

The main lip packings (5.1) and (5.2) are arranged facing the external water (W). In front of these packings, a spare lip packing (6) is arranged facing the external water (W).

The main lip packings (5.1) and (5.2) are formed as solid packings by a conventional method, while the auxiliary lip packings (6) are formed as elastically deformable hollow lip packings.

The spare lip packing (6) has a first position where the contact edge (6 ') moves away from the shaft (1) during normal operation, and a contact edge (6) when the main lip packing (5.1), (5.2) fails. ′) Takes two positions, a second position which is pressed against the shaft (1) to seal the shaft (1).

Connected to the cavity (7) of the spare lip packing (6) is one end of a pressure line (8) that moves the spare lip packing (6) from the first position to the second position by introducing pressurized water into the cavity. Has been done. The other end of the pressure conduit (8) is connected to a compression source (not shown) for supplying pressurized water.

Thus, when the pressurized water is not supplied to the cavity (7) of the preliminary lip packing (6), the contact edge (6 ') of the preliminary lip packing (6) is changed by the elastic repulsive force.
Located slightly above the upper surface of the shaft (1).

When the pressurized water is supplied to the cavity (7), the preliminary lip packing (6) is deformed and its contact edge (6 ') is pressed against the upper surface of the shaft (1). At that time,
By appropriately adjusting the pressure of the pressurized water, the contact edge (6 ') can be easily pressed against the shaft (1) with a desired contact pressure.

The spare lip packing (6) is in a position spaced from the shaft (1) during normal operation, that is, when the main lip packing is performing its normal function.

When the main lip packing (5.1) or (5.2) fails or leaks, the backup lip packing (6) is moved from the first position to the second position by a detection / notification system (not shown). , Acts as an extremely effective emergency packing.

As shown in FIG. 2, the preliminary lip packing (6) is formed with a plurality of holes (9) communicating from the cavity (7) to the space on the gaseous medium side. The openings of the holes (9) are circumferentially distributed in the vicinity of the contact edges (6 ') of the spare lip packing (6). This hole (9) makes it possible to always form a water film sufficient for the lubrication of the contact edge (6 ') of the spare lip packing (6).

Further, grooves (10) are circumferentially formed in the areas of the openings of the holes (9) of the auxiliary lip packing (6). By this groove (10), the water flowing out from the hole (9) is sent in the direction of the hydrodynamic direction toward the contact edge (6 '), the generation of the water film is promoted along this direction, and the lubrication is effective. It is supposed to be done.

EFFECTS OF THE INVENTION As described above, according to the present invention, since the spare lip packing is a hollow lip packing that can be elastically deformed, and pressurized water is introduced into the cavity of the lip packing in an emergency to operate the spare lip packing. The structure is extremely simple and the manufacturing cost can be reduced. Furthermore, since the pressurized water introduced into the cavity of the spare lip packing is intentionally leaked slightly to the outside from the area near the contact edge, effective lubrication of the contact edge of the spare lip packing is achieved. Can be achieved.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a seal structure according to the present invention applied to a stern tube of a ship, and FIG. 2 is a partially enlarged view showing a main part of a spare lip packing in the seal structure of FIG. It is a figure. (1) …… Shaft (2) …… Bushing (4.1), (4.2), (4.3), (4.4) …… Housing ring (5.1), (5.2) …… Main lip packing (6) …… Spare lip Packing (6 ′) …… Contact edge (7) …… Cavity (9) …… Hole (10) …… Groove (W) …… Liquid medium (L) …… Gaseous medium

Claims (5)

[Claims] 1. A seal structure for a rotating shaft for sealing a liquid medium (W) against a gaseous medium (L), the seal structure being arranged around a shaft (1) or a shaft bush (2). At least one radially extending main lip packing (5.1,5.2) in sealing contact with the shaft (1) or the shaft bush (2), and the shaft (1) or the shaft bush (2)
And a first position where the contact edge (6 ') is separated from the shaft (1) or the shaft bush (2) during normal operation, and when the main lip packing (5.1,5.2) fails. Two positions, a second position in which the contact edge (6 ') is pressed against the shaft (1) or the shaft bush (2) to seal the shaft (1) or the shaft bush (2). At least one radially extending elastically deformable hollow spare lip packing (6), which is connected to the cavity (7) of the spare lip packing (6) and introduces a pressurized medium into the cavity. A sealing structure comprising a pressure line (8) for moving the preliminary lip packing (6) from the first position to the second position by means of A plurality of holes (9) communicating from the cavity (7) to the space on the side of the gaseous medium are formed in the preliminary lip packing (6), and the opening of the holes (9) is the preliminary lip packing (6). ) Contact edge (6 ')
A seal structure for a rotating shaft, which is distributed in the circumferential direction in the vicinity of the. 2. A groove (10) is circumferentially formed in the area of the opening of the hole (9) of the spare lip packing (6) so as to flow out from the hole (9). Sealing structure for a rotating shaft according to claim 1, characterized in that water is delivered hydrodynamically in a direction towards the contact edge (6 '). 3. The rotating shaft is formed of a stern tube of a ship so that external water (W) is sealed against air (L), and two main lip packings (5.1, 5.).
2) are arranged in the axial direction of the shaft so as to face the external water (W), and the auxiliary lip packing (6) is provided in front of the main lip packing (5.2). ), The seal structure for the rotating shaft according to claim 1 or 2. 4. A rotating shaft according to claim 1 or 2, characterized in that the spare lip packing (6) is provided for each of the main lip packings. Seal structure. 5. Rotating shaft according to claim 1 or 2, characterized in that the pressure exerted on the contact edge (6 ') of the spare lip packing (6) is adjustable. Seal structure against.