Seal between mutually fixed surfaces

Abstract

Seal between mutually fixed surfaces comprises a metal ring, placed between graphite layers, where sections of the metal ring to be coated with graphite have a jagged profile. Both sides of the metal ring are coated with graphite in such a way that graphite layers and the metal ring form a seamless whole. Recesses are made in the seal on both sides between graphite rings, a hole is placed in their centre.

Claims

1. A seal assembly comprising a metal ring having or more holes, a first recess, and a second recess, wherein: the one or more holes extend from a first surface of the metal ring to a second surface of the metal ring, the first recess is located in the first surface and the second recess is located in the second surface, the first and second recesses are in communication with the one or more holes, the first and second recesses are concentric to the metal ring, and the first and second surfaces comprise a jagged portion; a first graphite layer and a second graphite layer, wherein the first graphite layer coats at least the jagged portion of the first surface of the metal ring, and wherein the second graphite layer coats at least the jagged portion of the second surface of the metal ring, whereby the metal ring and the first and second graphite layers form a unitary structure; a lid for a container, said lid comprising a lower surface, an upper surface, and one or more grooves, wherein the one or more grooves are formed in the lower surface of the lid; and one or more screws securing the lid to the metal ring, wherein the one or more screws are inserted through the one or more holes and into the one or more grooves in the lower surface of the lid; wherein the first and second recesses divide the seal into two sections, thereby creating two circuits which increase a tightness of the seal, and wherein the first and second recesses prevent radial extrusion outside of the metal ring over and entire operating pressure range.

2. The seal of claim 1, wherein at least two screws and at least two holes fasten the seal to the lid.

3. The seal of claim 1, wherein at least one hole is designed for a medium flow during a drying process and when seal cavity tightness is monitored.

4. The seal of claim 1, wherein thermally expanded graphite is used as graphite, and wherein the first and second recesses form a triangular profile.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Top view of the seal and cross section of the seal in points where holes for fastening the gasket by screws (A-A) are made and holes for medium flow during drying process and when gasket cavity is sealed (B-B) are shown on FIG. 1.

(2) Fastening of the seal is shown on FIG. 2.

EMBODIMENT OF THE INVENTION

(3) The seal is made of stainless steel ring 1, that is coated on both sides by thermally expanded graphite 2. Sections of the metal ring 1 to be coated by graphite 2, have jagged profile and graphite 2 is coated in the shape of rings on both sides of the metal ring 1. Height of teeth is from 0.3 to 0.5 mm, angle between teeth is 90°, thickness of graphite layer shall not exceed the height of teeth. Total thickness of the seal is from 3 to 6 mm.

(4) The metal base shall be coated by graphite using known technologies in such a way that layer of graphite and metal base shall be integral.

(5) Recess is made inside the seal on both sides and hole 3, designed to fasten the gasket by screws 4 in a groove of the lid 5, recess and hole 6 for medium flow during drying process and when gasket cavity is sealed.

(6) The gasket shall be installed on lower surface of the lid 5 and fastened by screws 4, installed in holes 3 including recess in the gasket. Then the lid 5 shall be installed on the body 7 and fastened by pins and nuts (they are not shown on Fig.). The seal is ready for operation.

(7) Test pressure shall be produced in cavity to monitor tightness through the hole 6, for this purpose, a hole connecting both parts of gasket with atmosphere is made in the lid 5. Hole outside the lid 5 shall be sealed by a plug with sealing ring made of thermally expanded graphite in operation condition. When tightness is monitored, a pipe connector shall be installed in hole 6, which can be connected to monitoring devices, for example, a pressure meter.

(8) Recess also allows to perform de-watering (dehydration) of the seal.

INDUSTRIAL APPLICABILITY

(9) Technical decision in compliance with the invention can be used to seal protective lids in casks (containers) for transportation and/or long-term storage of radioactive materials. The proposed seal shall provide tightness of protective lids in casks (containers) in normal operation and during emergencies in compliance with the requirements to casks (containers) of the specified purpose stipulated by the regulatory documents of the RF and recommendations of IAEA.