SU1227881A1 - End contact sealing - Google Patents

Description

one

The invention relates to power and chemical engineering and can be used in turbines, pumps and mixing devices.

The aim of the invention is to increase the tightness of the seal by maintaining the plane-parallel shape of the sealing gap with small gaps.

Figure 1 shows the design of the mechanical contact seal; in fig. 2 - diagram of forces, acting on the ring.

On the shaft 1, a rotatable sealing ring 2, mounted in the sleeve 3, is fixed. A non-rotatable sealing ring 4 is glued into the sleeve 5. Then the rings installed in the sleeves are rubbed to a non-flatness less than 0.5 µm. To the holder 5 and the body 6 of the node is welded- with the bellows 7, which presses the non-rotating ring to the rotating body. Inside the bellows assembly, a sleeve 8 is installed with a rubber ring 9, which seals the space between sleeve 8 and ring 4 and rubber ring 10, also sealed to the space between sleeve 8 and holder 5. Sleeve 8 has a variable cross section and can move in the axial direction . The ring 11 is screwed into the holder 5 with a spring 12 attached to it. The spring kinematically connects the holder 5 and the sleeve 8 and affects the position of the sleeve. In the space between the ring, the sleeve and the holder, the chamber A of the barrier fluid is connected, connected by a hole in the ring 4 to an annular groove on the working surface and compacted with rubber rings 9, 10 and 13. The annular groove divides the working surface into two working paths. the sleeve 8 and the holder 5 are arranged by an additional chamber B connected by holes in the holder 5 and the ring 4 with a group of grooves located on the outer working path of the ring, and sealed with rubber rings 10 and 14. The movement of the sleeve 8 in the axial direction is limited by a retaining ring 15 and : spring stiffness.

Mechanical contact seal works as follows.

12278812

At the initial moment of time, after the sealing rings 2 and 4 are pressed together by the bellows 7, the stress state of the rings changes, the flatness of the working surfaces is broken. The position of the sleeve 8 with a rubber ring 9 is determined by the stiffness of the spring 12. In this case, the rubber ring 9 occupies an intermediate position among its possible positions (the axial movement of the sleeve is limited by the retaining ring 15 and the rigidity of the spring 12 and, as a result, the position of the rubber ring 9 is limited on the left by the section of the ring, passing through the center of mass, on the right by the non-working end of the ring). Then chamber A is filled with a closing liquid under pressure of 0.2 MPa

20 greater than the pressure in the sealed cavity. At the same time, the sealing gap and chamber B. are filled. The power circuit of the auxiliary, axially movable ring 4, ring

25 is subject to deformation. As a result, the shape of the seal gap is from

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40

45

50

55

Is from the plane-parallel, which leads to a decrease in tightness, and consequently, reliability. With the confused form of the sealing gap, the pressure in chamber B connected to the group of grooves increases. The differential pressure acting on the sleeve 8 changes. The sleeve moves to the left, which is also facilitated by the spring 12. The power circuit of the ring changes in such a way that there is a tilting moment relative to the center of mass of the ring, which leads to such a deformation of the ring that a plane-parallel restoration takes place sealing gap forms. Thus, chamber B is a sensitive element with respect to the shape of the sealing gap and when the shape of the gap deviates from the plane-parallel pressure in chamber B changes, which leads to a change in the pressure drop that constantly acts on the sleeve. At the same time, the sleeve moves, the position of the secondary seal, the rubber ring 9, changes. This leads to a change in the power circuit of the ring. There is a tilting moment relative to the center of mass of the ring. The ring is deformed in such a way that the plane-parallel shape of the sealing gap is restored.

subjected to deformation. As a result, the shape of the seal gap

Is from the plane-parallel, which leads to a decrease in tightness, and consequently, reliability. With the confused form of the sealing gap, the pressure in chamber B connected to the group of grooves increases. The differential pressure acting on the sleeve 8 changes. The sleeve moves to the left, which is also facilitated by the spring 12. The power circuit of the ring changes in such a way that there is a tilting moment relative to the center of mass of the ring, which leads to such a deformation of the ring that a plane-parallel restoration takes place sealing gap forms. Thus, chamber B is a sensitive element with respect to the shape of the sealing gap and when the shape of the gap deviates from the plane-parallel pressure in chamber B changes, which leads to a change in the pressure drop that constantly acts on the sleeve. At the same time, the sleeve moves, the position of the secondary seal, the rubber ring 9, changes. This leads to a change in the power circuit of the ring. There is a tilting moment relative to the center of mass of the ring. The ring is deformed in such a way that the plane-parallel shape of the sealing gap is restored.

Similarly, work takes place with the diffuser shape of the sealing gap.

12278814

When the shaft rotates, the locking fluid lubricates the rubbing surfaces and protects them from contact.

Center of mass

FIG. 2

Editor A.Gulko

Compiled by I. Pashchenko

Tehred I. Veres Proofreader I. Muska

Order 2277/38 Circulation 880 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Claims (1)

END CONTACT SEAL, including rotating and non-rotating sealing rings, mounted in cages and pressed against each other by an elastic element, while non-rotating: the sealing ring with a cage covers an axially movable sleeve and forms a locking fluid chamber with with an annular groove made on the working surface of a non-rotating o-ring, dividing the working surface into two working tracks, and on the surface of the outer work? whose tracks a group of grooves is made, characterized in that, in order to increase the tightness of the seal, an additional chamber is formed between the axially movable sleeve and the cage enclosing it, which is connected to the group of grooves, the axially movable sleeve and the cage being kinematically connected by means of a spring. 5/1 10 8B of FIG. 1 1227881 A1