JPS6225578Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of a mechanical seal suitable for use under high pressure, such as the shaft seal of a canned water circulation pump in a thermal power plant.

Generally, this type of mechanical seal includes a rotating ring 2 fixed to the rotating shaft 1 side, as shown in FIG.
A stationary ring 4 is held on the side of the seal housing 3 so as to be non-rotatable and slidable in the axial direction, and is pressed in the direction of the rotating ring 2, and a stationary ring 4 interposed between the rings 2 and 4 A floating ring 6 is not rotatable but is allowed to move in the axial direction by a pin 5 protruding from the ring 5, and between the floating ring 6 and the stationary ring 4, both rings 4,
The ring 6 is provided with an elastic seal ring 7 such as an O-ring interposed under pinching pressure to seal between the rotating ring 2 and the floating ring 6, and the sealing fluid is sealed by the relative sliding rotation between the rotating ring 2 and the floating ring 6. It's becoming like that.

By the way, although the floating ring 6 is held non-rotatably by the pin 5, it is not completely prevented from moving in the radial direction, that is, in the direction orthogonal to the axis. There is a risk that the floating ring 6 may swing in the radial direction due to vibrations of the rotating ring 2 or fluctuations in the pressure of the sealing fluid. As a result, a good sealing function cannot be expected.

Therefore, in a mechanical seal equipped with the floating ring 6, preventing the swinging ring 6 from swinging in the radial direction is an important issue in terms of seal function.

Therefore, regarding conventional mechanical seals,
In order to solve this problem, as shown in FIG. 1, a cylindrical adapter 8 is provided which is fixed to the seal housing 3 to surround the outer peripheral surface of the floating ring 6.
The gap 9 between the inner peripheral surface of the adapter 8 and the inner peripheral surface of the adapter 8 is set to be narrow in order to prevent swinging of the floating ring 6 in the radial direction on the inner peripheral surface of the adapter 8 as much as possible.

However, even with this method, it is impossible to reliably prevent swinging of the floating ring 6 in the radial direction, and rather, because the gap 9 is narrowed, slurry etc. can clog and accumulate in the gap 9. As a result, the movement of the floating ring 6 in the axial direction is obstructed, causing problems such as malfunction of the floating ring 6 or damage or wear of the floating ring 6.

The present invention provides an improved mechanical seal that reliably prevents the radial movement of the floating ring without causing the above-mentioned disadvantages.

Next, one embodiment will be described with reference to FIG.

In the mechanical seal shown in Figure 2,
11 is a rotating ring retainer fixed to the rotating shaft 12;
13 is the O-ring 14, 15 attached to the rotating ring retainer 11.
and a rotating ring 17 fixed via a pin 16 or the like.
20 is a spring retainer fixed to the seal housing 18 via a flange 19; 20 is a stationary ring held non-rotatably and axially slidably on the spring retainer 17 via an O-ring 21;
A spring member 2 is inserted between the spring retainer 17 and the stationary ring 20 and presses the stationary ring 20 in the direction of the rotating ring 13;
A floating ring 24 is interposed between 3 and 20 so as to be movable in the axial direction, and is held unrotatable by a pin (not shown) protruding from the stationary ring 20 (see FIG. 1). and the floating ring 23 are interposed in a clamped state by the spring member 22,
An O-ring is an elastic sealing ring that seals between the two rings 20 and 23, and 25 is a stationary ring 20 and a floating ring 23.
This is a cylindrical adapter that protrudes from the spring retainer 17 to surround the outer peripheral surface of the spring retainer 17. This adapter 25 has a communication hole 25a facing the coolant inflow hole 18a formed in the seal housing 18.
The floating ring 23 is also provided with a coolant guide hole 23c that penetrates from the stationary ring 20 side toward the sealed end surface 26 with the rotating ring 13, and a coolant inlet hole 18a. The cooling liquid that has flowed into the gap 27 between the adapter 25 and the stationary ring 20 through the communication hole 25a is guided to the sealing end face 26 through the guide hole 23c of the floating ring 23 to the upper sealing fluid side 28.
It is designed so that the sealed end face 26 can be cooled well. Incidentally, a pumping ring (not shown) is attached to the rotating ring retainer 11, and the pumping ring allows the cooling fluid to be guided to the sealing fluid side 28 in a good manner. Note that 29 is an O-ring.

Although the structure of the mechanical seal described above is the same as that of a conventionally known one, the mechanical seal according to the present invention has been further improved in accordance with the present invention as follows.

That is, the opposing surface portions 20a, 23a of the stationary ring 20 and the floating ring 23 have the opposing surface portions 20a, 23a.
O-ring 24 interposed between 3a in a pinched state
An annular stepped portion 20 with the same outer diameter that can be fitted into the
b and 23b are formed in a protruding manner, respectively, and an O-ring 24 is fitted and engaged with the outer periphery of both stepped portions 20b and 23b in a state in which the O-ring 24 is straddled approximately evenly. Both step portions 20b and 23b are a stationary ring 20 and a floating ring 2, respectively.
3, and the amount of protrusion from the opposing surface portions 20a, 23a is approximately the same, and when the end surfaces of both step portions 20b, 23b are abutted, the opposing surface portions 20a, The O-ring 24 is set to be clamped between the O-rings 23a to produce a predetermined sealing force.

Furthermore, in this embodiment, the gap 30 between the outer circumferential surface of the floating ring 23 and the inner circumferential surface of the adapter 25 is set relatively large, and
Although the O-ring 31 provided on the inner circumference of the floating ring 23 allows the floating ring 23 to move in the axial direction, the floating ring 2
3 and the inner peripheral surface of the adapter 30 are sealed.

With the above configuration, the O-ring 24 for sealing between the stationary ring 20 and the floating ring 23
is fitted onto the step portion 20b of the stationary ring 20 which is slidable in the axial direction but held immovable in the radial direction, and is held immovable in the radial direction with respect to the stationary ring 20, In addition, the floating ring 23 has its stepped portion 23b fitted into the O-ring 24, so that the O-ring
Since it is held immovably in the radial direction with respect to the ring 24, the floating ring 23 is held immovably in the radial direction by the stationary ring 20 via the O-ring 24. In other words, the floating ring 23 and the stationary ring 20 are held in a state where their axes coincide with each other.

Therefore, the floating ring 23 is effectively prevented from swinging in the radial direction due to vibrations of the equipment to which the mechanical seal is attached or fluctuations in the pressure of the sealing fluid. Moreover, since the O-ring 24 that holds the floating ring 23 is made of an elastic material, this combined with the fact that the stationary ring 20 is also held by the O-ring 21 made of an elastic material means that the vibrations of the device are transmitted to the stationary side member. It is absorbed and relaxed without being transmitted to 20 and 23, and the swinging of the floating ring 23 in the radial direction is more effectively prevented.

Furthermore, unlike the conventional device mentioned at the beginning, there is no need to restrict the movement of the floating ring 23 in the radial direction by the inner circumferential surface of the adapter 25, so the gap 30 between the floating ring 23 and the adapter 25 is made larger than necessary. There is no need to set the gap 30 to a narrow one, and the gap 30 can be set relatively large.
There is no risk that slurry or the like will accumulate on the ring, and it is possible to reliably prevent the occurrence of inconvenient situations such as malfunction, damage, or wear of the floating ring 23 due to the accumulated slurry or the like. This effect becomes more remarkable because, as described above, the floating ring 23 does not swing in the radial direction, and there is no possibility that the floating ring 23 will come into contact with the adapter 25.

From the above, according to the mechanical seal according to the present invention, the sealing function at the sealed end face 26 of the rotating ring 13 and the floating ring 23 is always well exhibited.

By the way, there is an O-ring 24 which is a seal ring for sealing between the stationary ring 20 and the floating ring 23, and a stepped portion 2 of the floating ring 23 into which the O-ring 24 is fitted.
3b is also present and necessary in conventional mechanical seals, as can be easily understood with reference to FIG.

Therefore, in the mechanical seal according to the present invention, the parts that require structural changes in order to achieve the above-mentioned effects are, to put it simply, the stationary ring 20.
Since only the stepped portion 20b is formed, the structure of the mechanical seal does not become unnecessarily complicated. This effect is particularly important in mechanical seals that require a simple structure.

Further, in the above embodiment, the floating ring 23 is provided with the coolant guide hole 23c facing the sealed end surface 26, and the gap 30 between the floating ring 23 and the adapter 25 is also covered by the O-ring 31. 30 is set relatively large to prevent the accumulation of slurry, etc., the coolant flowing in from the coolant inflow hole 18a does not flow out from the gap 30 to the sealing fluid side 28 and is ensured. Guide hole 2
3c to the sealed end surface 26. Therefore, the sealing end face 26 can be cooled more effectively, which is extremely advantageous in terms of sealing function.

Furthermore, since the O-ring 31 also has the function of holding the outer circumferential surface of the floating ring 23, together with this, it is possible to more reliably prevent the floating ring 23 from swinging in the radial direction.

It should be noted that the present invention is not limited to the above-mentioned embodiment. For example, as shown in FIG. . In this way, the stepped portions 20b and 23 formed on the stationary ring 20 and the floating ring 23
In short, b may be an annular member that can be engaged with the O-ring 24 at the same time.

In addition, as shown in FIG.
It is also possible to eliminate the ring 31. In this case as well, the swinging of the floating ring 23 in the radial direction causes the O-ring 2
4, it is not necessary to set the gap 30 so narrow that there is a risk that slurry or the like may accumulate therein. The outer circumferential surface of the floating ring 23 is shaped so that the cooling liquid flowing out from the gap 30 can be guided to the sealed end surface 26 in a good manner.

Further, the elastic seal ring interposed between the stationary ring 20 and the floating ring 23 is not limited to the O-ring 24 as in each of the above embodiments, but may be a square ring, for example. Of course, the shapes of the stepped portions 20b and 23b formed in the stationary ring 20 and the floating ring 23 are appropriately designed depending on the shape of the seal ring to be used.

In any case, as is clear from the above explanation, the mechanical seal of the present invention prevents vibrations of the floating ring in the radial direction due to equipment vibrations, pressure fluctuations of the sealed fluid, etc., and interference between the floating ring and the adapter. It is possible to reliably prevent the accumulation of slurry or the like in the gap, and it is possible to always perform the sealing function satisfactorily at the sealed end surfaces of the rotating ring and the floating ring.

Moreover, although the mechanical seal of the present invention has such effects, its structure is not complicated in any way, and there is no problem in terms of seal function and manufacturing.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of the main parts of a conventional example, FIG. 2 is a longitudinal sectional side view of an embodiment of the mechanical seal according to the present invention with the lower half omitted, and FIGS. FIG. 4 is a vertical sectional side view of the main parts showing other embodiments. 13... Rotating ring, 20... Stationary ring, 23... Floating ring, 24... O ring (elastic seal ring),
25...adapter, 30...gap, 31...O
ring.

Claims (1)

[Scope of utility model registration request] A mechanical seal in which a floating ring is interposed between a rotating ring and a stationary ring, and an elastic seal ring is interposed between the floating ring and the stationary ring under clamping pressure. An annular stepped portion that can be engaged with the seal ring is formed on either of the rings, and the engagement between the stepped portions and the seal ring prevents the floating ring from moving in the radial direction relative to the stationary ring. A mechanical seal that is characterized by: