Fluid seal for use in rotary regenerator

Claim 2

A rubbing contact fluid seal for use on the hot side in the rotary regenerator portion of a gas turbine engine, which portion includes a rotatable annular matrix, said seal comprising: a seal member made of carbon base material, said seal member having first and second surfaces, said first surface being contactable with the rotatable radial face on the hot side of said rotatable annular matrix, said second surface being directly contactable with hot exhaust gases before they pass through the matrix and with hot intake air after it passes through the matrix; and a heat-resistant layer formed on said second surface, allowing the major part of said first surface of carbon base material to be exposed as it is for rubbing contact with the hot side radial face of the rotatable annular matrix.

Claim 3

A rubbing contact fluid seal as claimed in claim 1, in which said heat-resistant layer comprises silicon carbide.

Claim 4

A rubbing contact fluid seal as claimed in claim 2, in which said heat-resistant layer is formed by contacting said second surface of said seal member with silicon monoxide gas under conditions so that said surface and the silicon monoxide gas react with each other.

Claim 5

A rubbing contact fluid seal as claimed in claim 3, in which the thickness of said heat-resistant layer is in the range from 0.1 to 0.4 mm.

Claim 6

A rubbing contact fluid seal as claimed in claim 2, in which said heat-resistant layer is formed by first putting silicon powder on said second surface of said seal member and thereafter heating the silicon powder on said second surface in an atmosphere of inert gas to a temperature sufficient to produce silicon carbide.

Claim 7

A rubbing contact fluid seal as claimed in claim 5, in which the thickness of said heat-resistant layer is in the range from 0.1 to 0.4 mm.

Claim 8

A rubbing contact fluid seal as claimed in claim 3, further comprising a stationary holder on which said seal member is securely mounted.

Claim 9

A rubbing contact fluid seal as claimed in claim 7, in which said seal member includes an annular portion having inner and outer cylindrical side surfaces which are concentrically arranged with each other, the inner cylindrical side surface being directly contactable with the exhaust gases before they pass through the matrix and comprising a portion of said second surface, and top and bottom annular flat surfaces which are parallel with each other, the top flat annular surface being directly contactable with the rotatable radial face of the matrix and comprising said first surface, and the bottom flat annular surface being secured to said stationary holder.

Claim 10

A rubbing contact fluid seal as claimed in claim 8, in which said heat-resistant layer is formed on the inner and outer cylindrical side surfaces and on the bottom flat annular surface of said annular member.

Claim 11

A rubbing contact fluid seal as claimed in claim 3, in which said heat-resistant layer is formed by partly covering the surfaces of said seal member with a covering member, maintaining said second surface of said seal member uncovered, and thereafter contacting said uncovered surface of said seal member with silicon monoxide gas to cause carbon of said with uncovered surface to react with silicon monoxide gas.

Claim 12

A rubbing contact fluid seal as claimed in claim 8, in which said heat-resistant layer is formed by covering the outer cylindrical side surface and the top and bottom flat annular surfaces with a covering member, and thereafter contacting the inner cylindrical side surface with silicon monoxide gas to cause carbon of the inner cylindrical side surface of said seal member to react said with silicon monoxide gas.

Claim 13

A rubbing contact fluid seal as claimed in claim 9, in which said heat-resistant layer is formed by covering only the top flat annular surface of said seal member with a covering member, and thereafter contacting the inner and outer cylindrical surfaces and the bottom flat annular surface with silicon monoxide gas to cause carbon of the three surfaces of the seal member to react with said silicon monoxide gas.

Claim 14

A rubbing contact fluid seal as claimed in claim 1, in which said heat-resistant layer is a coating formed by spraying a mixture of nickel oxide and calcium fluoride onto said second surface of said seal member.

Claim 15

A rubbing contact fluid seal as claimed in claim 13, in which the thickness of said heat-resistant layer is in the range from 0.1 to 1.0 mm.

Claim 16

A rubbing contact fluid seal for use on the hot side in the rotary generator portion of a gas turbine engine, which portion includes a rotatable annular matrix, said seal comprising: a seal member comprising a carbon base material and formed with first and second surfaces, said first surface being contactable with the rotatable radial face on the hot side of said rotatable annular matrix, said second surface being directly contactable with hot exhaust gases before they pass through the matrix and hot intake air after it passes the matrix; and a heat-resistant layer formed on said second surface, allowing the major part of said first surface of carbon base material to be exposed as it is for rubbing contact with the hot side radial face of the rotatable annular matrix, said heat-resistant layer comprising a material selected from the group consisting of silicon carbide and a mixture of nickel oxide and calcium fluoride.

Claim 17

A rubbing contact fluid seal for use on the hot side in the rotary generator portion of a gas turbine engine, which portion includes a rotatable annular matrix, said seal comprising: a seal member comprising a carbon base material and formed with first and second surfaces, said first surface being contactable with the rotatable radial face on the hot side of said rotatable annular matrix, said second surface being directly contactable with hot exhaust gases before they pass through the matrix and hot intake air after it passes the matrix; and a heat-resistant layer formed on said second surface, allowing the major part of said first surface of carbon base material to be exposed as it is for rubbing contact with the hot side radial face of the rotatable annular matrix, said heat-resistant layer comprising a material selected from the group consisting of silicon carbide and a mixture of nickel oxide and calcium fluoride.

Claim 18

A rubbing contact fluid seal for use on the hot side in the rotary regenerator portion of a gas turbine engine, which portion includes a rotatable annular matrix, said seal comprising: a seal member comprising a carbon base material and formed with an annular portion having inner and outer cylindrical side surfaces which are concentrically arranged with each other, the inner cylindrical side surface being directly contactable with hot exhaust gases before they pass through the matrix and hot intake air after it passes through the matrix, and top and bottom annular flat surfaces which are parallel with each other, said top flat annular surface being directly contactable with the hot side rotatable radial face of the matrix and the bottom flat annular surface being secured to a stationary holder; and a heat-resistant layer formed on the inner cylindrical side surface of the annular portion of said seal member, allowing the major part of said top flat annular surface of carbon base material to be exposed as it is for rubbing contact with the hot side radial face of the rotatable annular matrix, said heat-resistant layer comprising a material selected from the group consisting of silicon carbide and a mixture of nickel oxide and calcium fluoride.

Claim 19

A rubbing contact fluid seal for use on the hot side in the rotary regenerator portion of a gas turbine engine, which portion includes a rotatable annular matrix, said seal comprising: a seal member comprising a carbon base material and formed with an annular portion having inner and outer cylindrical side surfaces which are concentrically arranged with each other, the inner cylindrical side surface being directly contactable with hot exhaust gases before they pass through the matrix and hot intake air after it passes through the matrix, and top and bottom annular flat surfaces which are parallel with each other, said top flat annular surface being directly contactable with the hot side rotatable radial face of the matrix and the bottom flat annular surface being secured to a stationary holder; and a heat-resistant layer formed on the inner cylindrical side surface of the annular portion of said seal member, allowing the major part of said top flat annular surface of carbon base material to be exposed as it is for rubbing contact with the hot side radial face of the rotatable annular matrix, said heat-resistant layer comprising a material selected from the group consisting of silicon carbide and a mixture of nickel oxide and calcium fluoride.

Claim 20

A fluid seal according to claim 16, wherein said seal member further comprises a cross-piece extending across said annular portion, said cross-piece having a top surface which comprises exposed carbon base material and which is directly contactable with the hot side rotatable radial face of the matrix, and two side surfaces which are coated by said heat-resistant layer.