JPH0137625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to seal assemblies and, more particularly, to composite seal assemblies for use with rotating shaft and housing devices where differential pressures of liquid exist.

In many industrial fields, seals are used to prevent fluids or bearing lubricants that are pumped or mixed from leaking out of housings or bearings, and to prevent fluids being pumped or foreign objects from entering the bearings. It is extremely important to have a

There is a real need for a more effective sealing arrangement than that for conventional ball bearing shafts and housings, such as that disclosed in U.S. Pat. No. 4,114,902 (1978) to the present inventor.

The above-mentioned patent shows a seal structure consisting of two rings, the flange of one ring having at least one groove relative to the groove on the other ring, into which the flange fits. However, grooves are further provided on the inward walls of the grooves on the other ring, and these grooves serve to prevent foreign matter from entering in the axial direction along the shaft.

The present invention is effective when prior art seal structures are not effective, i.e. when the seal structure is submerged below the level of the lubricant, or when differential pressure exists, such as in the case of rotary pumps or mixers. This provides an excellent sealing device. In situations such as those described above, if the seal structure is below the lubricant liquid level, a pressure difference from high pressure to low pressure will occur, and the prior art seal will not be as effective as the improved sealing device of the present invention. , cannot prevent leakage of lubricant or fluid or intrusion of foreign objects.

The sealing system of the present invention is a "radial" seal and is not susceptible to the factors that damage conventional "axial end" mechanical seals.
The seal according to the invention is essentially a pressure differential seal, which can prevent leakage of lubricant from the bearing and the passage of pumped fluid into or out of the sealed inner area. The sealing device according to the present invention is extremely effective for the above purposes.

The present invention provides an improved seal assembly for differential fluid pressures exerted on a shaft and housing. The seal assembly includes a multi-ring seal structure disposed between the shaft and the housing, the multi-ring structure having a first ring press-fit into the housing and a second ring press-fit onto the shaft. It is arranged so that it is done. The seal assembly of the invention further includes a pressure seal device of the self-compensating seal type disposed in a multi-ring structure radially relative to the shaft, said pressure seal device comprising a cover and a pressure seal device disposed in a multi-ring structure. It has a support spring partially encased in the cover.

The cover of the pressure seal means is U-shaped and has legs or lips that press against each ring of the multi-ring seal structure, thereby sealing the member against the sealing surface of the shaft. contact, thus preventing leakage of liquid from the bearing and housing and the ingress of foreign matter into the bearing.

The seal assembly according to the invention can be used with a stationary shaft and a rotating housing, a stationary housing and a rotating shaft, or a shaft and a housing that rotate together relative to each other. obtain. Note that the housing may be a pump housing or a bearing housing.

Next, this invention will be explained according to examples.

FIG. 1 shows the manner in which the seal assembly of the present invention is used. As shown, the seal assembly is placed between the rotating shaft 10 and the housing 12, and races and bearings such as those shown in the aforementioned U.S. Pat. The races and bearings are provided with lubricant or, in the case of a rotary pump or mixer, energy is provided to impart pressure and motion to the fluid.

Seal assembly 14 includes multi-ring seal structure 1
6 and a sealing device 18, which includes an annular enclosure or a first gland (annular recess) 2 of a multi-ring structure 16 arranged around the rotation axis 10.
It is installed within 0.

The multi-ring structure 16 includes a first ring 22, a second ring 24, and a third ring 26 located at the opposite end of the first ring. An insert 28 is placed in the gland 20 formed by the first ring 22 and the second ring 24 . The second gland (annular recess) 30 is connected to the first ring 22 and the third
ring 26.

As shown in FIGS. 1 and 2, there is only a sealing device 18 located within the multi-ring structure, which may be located in either gland 20 or 30.

As shown in FIGS. 1 and 2, the sealing device 18 includes a seal of the multi-ring structure,
and provides a highly effective seal to the housing 12. The sealing device 18 has an annular cover 32 and a support spring 34 partially encapsulated in the cover 32, the support spring 34 serving to keep the sealing device 18 in its particular shape. Supplement sufficient resilience.

A pressure seal device 18 is placed within the gland 20 of the multi-ring structure 16 and is connected to the second ring 24 (rotor).
When opened by internal or external pressure, it is pressed against the surfaces of the insert 28 and the first ring 22 and second ring 24 (FIG. 3).

The first ring 22 of the multi-ring structure 16 has annular grooves 35 and 36 extending in the axial direction at both ends,
A second ring 24 placed on both ends of the first ring 22
and the third ring 26 each have an annular flange 37.
and 38, with flange 37 fitting into groove 35 and flange 38 fitting into groove 36.

The first ring 22 has two outer annular grooves 40 in which a conventional O-ring 41 is inserted.
is placed, the O-ring 41 is brought into pressure contact with the groove of the corresponding shape in the housing 12, and the first ring 22 (stator)
is fixed to the housing 12.

The second ring 24 and the third ring 26 have inner annular grooves 42 and 43, respectively, in which are mounted O-rings 44 and 45, respectively, for friction drive and static sealing. The second and third rings placed around the rotational shaft 10 rotate around the rotational shaft 10 due to the frictional engagement of the O-rings 44 and 45 between them and the rotational shaft 10.
It is fixed to a rotating shaft so that it rotates at the same time. Therefore, in the above three rings, the first ring 22 is attached to a stationary body (for example, the housing 12), and the second ring 22 is attached to a stationary body (for example, the housing 12).
Ring 24 and third ring 26 are mounted for rotation (eg, rotation shaft 10). In the seal function,
The first ring 22 and the second ring 24 and the first ring 22 and the third ring 26 are sealed along radial (circumferential) lines of contact, i.e., the stationary first ring 22 is sealed. sealed against the second ring 24 rotating along the surface 46;
The first ring 22 is sealed against the rotating third ring 26 along a sealing surface 47. These sealing surfaces must have a certain degree of smoothness and high hardness to form a stable and reliable seal to prevent fluid leakage. Contaminants, such as foreign matter and wear particles in the pumped fluid, are centrifuged at the contact surface between the rotating body and the stationary body before reaching the sealing surface.

In case the radial sealing surfaces deteriorate or break, fluid leakage is prevented by a specially shaped labyrinth groove 48 created in the stationary first ring 22 (see FIG. 5). That is, as shown by arrow 49 in FIG.
A hydraulic dam effect is provided between the two to prevent fluid leakage.

Additionally, the symmetrical shape of the seal assembly 14 (i.e., the presence of a rotating second ring 24 and a third ring 26) allows for e.g.
Leakage liquid due to damage to the ring 24 is transferred to the housing 1.
It is discharged from the discharge hole 52 provided in 2. Since the seal device 18 is not provided between the first ring 22 and the third ring 26 on the opposite side, the problem of seal deterioration as described above does not occur.

As shown in FIGS. 1, 2 and 3, the sealing device 18 includes a cover 32 made of Teflon compound or the like and having a U-shaped cross section.
The support spring 34 is partially enclosed in the cover 32. The support spring 34 is preferably made from helically wound flexible wire, said wire being made in the form of a flexible tube. Cover 32 may be made from a chemically inert, low friction material, Teflon being highly suitable, although other chemically inert, low wear materials may also be used.

The cover 32 has legs 54 having lips 56 that are pressed against a surface 58 of the first ring 22 and a surface 60 of the second ring 24, respectively (FIG. 3). Furthermore, the cover 32
2 and a flat back surface 62 for pressing against the side of gland 20 formed by second ring 24 to secure sealing device 18 in position. Furthermore, an insert 28 can be provided to secure the sealing device 18 in place. Note that the interpolator 28 is not used in the embodiment shown in FIG.

3 and 4 show sealing device 18 placed within gland 20 of multi-ring structure 16. FIG.
As shown in the figure, the spring force (of the support spring 34) causes the material of the cover 32 (for example, Teflon) to flex and deform, so that the surface 58 of the first ring 22, the surface 60 of the second ring 24, and the surface 64 of the first ring are bent. A discontinuously separated face seal is formed. Due to this cold deformation of Teflon, the first to third rings of the multi-ring structure 16 are
The shape of the contact portion of the cover 32 matches the ring, and these members are pressed to bring them into sealing contact, and the rotating shaft 1
0 sealing surface 50 to provide an effective and reliable seal against differential pressure (ΔP). That is, when the legs 54 of the cover 32 are opened by internal or external pressure, the lips 56 open the first ring 22 and the second ring 2.
4 and into sealing contact, these rings are pressed against the surface 50 of the rotating shaft 10, thereby preventing leakage of fluid from the bearing and housing and entry of foreign matter into the bearing and fluid from outside the housing. Things can be prevented. The above foreign matter is
Since its specific gravity is greater than that of the fluid, it is separated outwardly by centrifugal force before entering the contact surface.

The support spring 34 in the sealing device 18 is made of resilient wire and provides permanent elasticity to the sealing device 18, so that the lip of the cover 32 can be attached to the components of the multi-ring structure ( For example, the first
It remains pressed against the surface of the ring 22).

The Teflon cover 32 is thermally and chemically resistant, chemically inert, and resistant to virtually all solvents. Furthermore, this cover 32 can be heated from approximately -254℃ (-425〓) to approximately
Can withstand temperature ranges up to 500°C.

The pressure applied at the location where the sealing device is used determines the effective seal obtained according to the means or force that presses the lips against the surfaces of the first and second rings. When the seal assembly is used, for example, when low pressure is applied to the rotating shaft and housing, the surface 58 of the first ring 22 on which the lip 56 of the cover rests due to the support spring 34 and the surface of the second ring 24 on rotation. It is lightly pressed against 60. When the seal assembly is used at high pressure differentials, the fluid pressure around the axis of rotation and the housing forces the lip 56 against the surfaces of the first ring 22 and second ring 24 more strongly in proportion to said pressure. .

The contact pressure in the radial contact between the first ring 22 and the second ring 24 of the multi-ring structure 16 is:
Differential pressure applied to the seal at sealing surface 46 (ΔP)
This differential pressure opens the cover legs 54 and increases the contact force at the sealing surface.

The sealing body according to the present invention can be widely used from high pressure to low pressure when it is necessary to seal liquids having differential pressures. That is, the packing box lubricant of a centrifugal pump or a rotary pump (constant volume pump) can be used for lubricated bearings that are placed higher than the seals and apply static pressure to the seals.

Typically, this seal assembly is a plug-in cartridge type that is simple in design and easy to install in equipment, so it is suitable for use on rotating machinery (e.g., pumps, transmissions, turbines, motors, mixers, and pillow blocks). can be conveniently used during transfers). The contact of this seal assembly is not axial but radial.
Therefore, factors that would have an adverse effect on the ``axial end face contact type'' sealing means are eliminated or their influence is drastically reduced.

The above factors include axial movement, radial eccentricity or misalignment, shock loads, lack of verticality due to thermal or mechanical causes, axial misalignment during installation, and axial alignment between engaging parts. directional tension, etc.

In addition, the contact surfaces within the seal assembly can be processed in a variety of ways, regardless of whether the equipment in which it is used is rotary, stationary, or reciprocating. input, smoothing, etc.).

[Brief explanation of drawings]

FIG. 1 is a sectional view of a seal body, rotating shaft and housing according to the present invention, FIG. 2 is an enlarged partial sectional view of the seal assembly, and FIG. 3 is a sectional view of the seal assembly placed in the gland of the seal assembly. FIG. 4 is an enlarged partial view of the sealing device shown in FIG. 3, and is an enlarged view of the area circled in FIG. The condition diagram, FIG. 5, shows the relationship between the groove of the first ring of the seal assembly and the surface of the rotating shaft, and also shows the control of fluid flow in the event that the contact part of the seal device is damaged or worn. FIG. DESCRIPTION OF SYMBOLS 10... Rotating shaft, 12... Housing, 14... Seal assembly, 16... Multi-ring seal structure, 18...
Seal device, 22...first ring, 24...second ring, 26...third ring, 32...cover, 34...support spring, 41, 44, 45...O ring, 48...labyrinth groove.

Claims (1)

[Scope of Claims] 1. A hydraulic pressure differential seal assembly used with a rotating shaft and a housing and disposed between the rotating shaft and the housing, comprising: a first ring, a second ring, and a third ring 3;
a multi-ring seal structure comprising members, the first ring having an annular recess opening in the axial direction at opposite ends thereof, and a second ring and a third ring having an annular recess at opposite ends of the first ring; an annular flange disposed in each of the annular recesses of the first ring and in close engagement with the annular recesses of the first ring, b. 1. A hydraulic pressure differential seal assembly comprising: a U-shaped cover having an opening; and a pressure seal body comprising a support spring housed within the U-shaped cover and imparting a restoring force to the U-shaped cover. 2. The U-shaped cover according to claim 1, wherein the U-shaped cover is brought into pressure contact with the members of the multi-ring seal structure, thereby bringing these members into pressure contact and sealing contact with the sealing surface of the rotating shaft. Hydraulic pressure differential seal assembly. 3. The hydraulic differential seal assembly of claim 1, wherein said U-shaped cover is comprised of a chemically inert, low friction material. 4. The hydraulic pressure differential seal assembly according to claim 3, wherein the U-shaped cover is made of tetrafluoroethylene polymer. 5 The U-shaped cover is heated from approximately -254℃ to approximately 260℃.
5. A hydraulic differential seal assembly as claimed in claim 4, characterized in that it has resistance to damage in a temperature range of . 6. A hydraulic pressure differential seal assembly according to claim 1, wherein said support spring comprises a helically wound elastic flat wire. 7. The hydraulic pressure differential seal assembly according to claim 1, wherein the wire has elasticity to permanently impart elasticity to the pressure seal device. 8. The support spring presses the U-shaped cover, with the U-shaped opening extending axially, against the members of the multi-ring seal structure, thereby sealing these members radially with respect to the axis of rotation with minimal pressure. A hydraulic pressure differential seal assembly as claimed in claim 1, characterized in that the seals are formed by contacting each other to form a seal. 9 Pressure within the shaft of rotation and the housing presses the U-shaped cover, with the U-shaped opening extending axially, against the multi-ring seal structure, thereby causing these members to radially rotate relative to the shaft of rotation. 2. The hydraulic pressure differential seal assembly according to claim 1, wherein the seal is formed by making sealing contact in proportion to the pressure contact force.