Method of protecting a limited-displacement mechanical system against an agressive medium

• US 4,830,520 A
• Filed: 11/09/1987
• Issued: 05/16/1989
• Est. Priority Date: 06/27/1983
• Status: Expired due to Fees

• Current Assignee: Alsthom-Atlantique
• Original Assignee: Alsthom-Atlantique
• Inventors: Obrecht, Georges
• Primary Examiner(s): Footland, Lenard A.
• Application Number:
  US07/119,271
• Time in Patent Office: 554 Days
• Field of Search: 277/72 FM, 277/135, 277/136, 384/526, 384/527, 384/576, 384/477, 384/478, 384/906, 105/226, 74/574, 464/20, 464/91
• US Class Current: 384/477
• CPC Class Codes: E21B 4/003 Bearing, sealing, lubricating details for roller bits E21B10/22
• CPC Class Codes: E21B 4/02 Fluid rotary type drives
• CPC Class Codes: F16C 11/04 Pivotal connections hinges for doors, windows or wings E05D
• CPC Class Codes: F16C 2352/00 Apparatus for drilling
• CPC Class Codes: F16C 33/72 Sealings
• CPC Class Codes: F16J 15/3436 Pressing means
• CPC Class Codes: F16J 15/36 connected by a diaphragm or bellow to the other member
• CPC Class Codes: Y10S 384/906 Antirotation key

Abstract

The mechanical system is surrounded by a protective chamber (33) and is filled with a liquid material which is transformed in situ into a resilient material that adheres to the inside walls of the chamber and which protects the operative surfaces of the mechanical system.

Claims

1. In an operative limited-displacement mechanical system protected from a surrounding aggressive medium, said mechanical system comprising:

operative parts having hard operative surfaces in moving contact with each other in working zones for directly transmitting working forces in operation of said system, said operative parts having limited displacements,

surrounding parts defining a protective chamber surrounding said operative surfaces together with an internal volume enabling said limited displacements of said operative parts,

at least one rigid link part fixed to one of said operative parts for transmitting motion thereof outside said protective chamber, said link part having therefor transmission motion between extreme positions,

said protective chamber having at least one outlet through which said rigid link part passes defining an outlet gap around said link part for enabling said transmission motion,

and a filler material filling said protective chamber for protecting said mechanical system from said surrounding aggressive medium,

the improvement comprising;

said filler material including at the same time portions in a resilient state and portions in a liquid-like state,

said filler material portions in said resilient state being made of a high polymer which chemical bonds therein, said high polymer having a tensile strength of 3 to 30 newtons per square millimeter, a shear strength of at least 20 newtons per centimeter, and an elastic limit of at least 150%,

said system comprising means for adhering said filler material portions in said resilient state to said operative, surrounding and link parts in said protective chamber,

said outlet gap being filled with an outlet filler material which is a said portion of said filler material in said resilient state and which is subject to deformation during said transmission motion, said outlet gap being large enough beyond said extreme positions of said link part such that said deformation of said outlet filler material never exceeds said elastic limit of said filler material in said resilient state,

said filler material including said portions in said liquid like state at least in said working zones, said filler material portions in said liquid like state being made of said high polymer in which some of said chemical bonds have been destroyed by said working forces,

whereby, at the same time,

overpressures of said surrounding medium can be accommodated by said outlet filler material which is backed up by the remaining portions of said filler material filling said chamber,

said chemical bonds enable said outlet filler material to resist said aggressive surrounding medium,

and said filler material does not hinder said limited displacements of said operative parts.

2. The system according to claim 1, wherein said filler material has a thermal conductivity of greater than 0.2 W/m°

K.

3. The system according to claim 1, wherein said filler material has a hardness lying in the range of 20 to 70 on the Shore A scale.

4. The system according to claim 1, wherein said filler material has a Young'"'"'s modulus in the range of 0.5 to 20 N/mm².

5. The system according to claim 1, wherein said means forming said rigid protective chamber comprises at least one compensation opening for increasing the range of possible variations in the inside volume of said chamber by enabling the soft resilient high polymer to deform elastically through said opening.

6. The system according to claim 1, wherein said improvement further resides in said filler material being one material chosen from the group consisting of chlorosilanes and siloxanes, thus ensuring good resistance to chemical attack.

7. The system according to claim 6 or 1, wherein said improvement further resides in said operative parts being made of a metal capable of withstanding stresses of greater than 100 N/mm² in the zones adjacent to the operative surfaces in contact with other operative surfaces.

8. An improved operative limited-displacement mechanical system for operation in a surrounding aggressive medium, said mechanical system comprising:

operative parts having limited displacements in said mechanical system and having hard operative surfaces for forming a contact therebetween in at least one bearing point, said bearing point having limited displacements in at least one working zone for directly transmitting working forces for operation of said mechanical system,

surrounding parts defining a protective chamber which surrounds said operative surfaces together with an internal volume enabling said limited displacements of said operative parts, and which has at least one outlet,

at least one rigid link part passing through said outlet and fixed to one of said operative parts for transmitting motion thereof outside said protective chamber, said link part having limited displacements between extreme positions and defining an outlet gap therearound in said outlet,

and a soft filler material filling said protective chamber for protecting said mechanical system from said aggressive medium without substantially hindering said limited displacements, a portion of said filler material which is in said outlet gap being an outlet portion which is exposed to overpressure thrusts and to erosion from said aggressive medium,

the improvement comprising;

said filler material including, after operation of said mechanical system, resilient portions wherein said filler material is in a resilient state and liquid like portions wherein said filler material is in a liquid like state, said filler material in said resilient state being a high polymer including breakable chemical bonds which confer on it a tensile strength of 3 to 30 newtons per square millimeter, a shear strength of at least 20 newtons per centimeter, and an elastic limit of at least 150%, said breakable chemical bonds being breakable under deformation so as to place said filler material into said liquid like state,

said resilient portions occupying zones which are distant from said working zone and in which deformations applied to said filler material by said limited displacements are relatively small whereby said relatively small deformations allow said breakable chemical bonds to be maintained, without substantially hindering said limited displacements,

said outlet gap being large enough beyond any one of said extreme positions of said link part such that said limited displacements of said link part apply relatively small deformations to said outlet portion whereby said resilient portions include said outlet portion, and said maintained breakable chemical bonds allow said outlet portion to resist said erosion by said aggressive medium,

said system further comprising means for adhering at least said outlet portion of said filler material to said surrounding and link parts, and

said liquid like portions occupying at least said working zone wherein said limited displacements of said bearing point applies relatively great deformations which have broken said breakable chemical bonds, whereby said filler material no longer hinders said forming of said contact and said limited displacements of said bearing point while said breakable chemical bonds are maintained in said outlet portion against said thrusts of said aggressive medium thanks to said outlet portion being backed up by a plenum which is made of the remaining resilient portions and the said liquid like portions.