Abstract A composite sealing structure for sealing the gap between stationary and moving surfaces of a gas impelling device, for example a turbine. Preferably, the sealing structure is on the surface of the stationary member. The sealing structure is adapted, in the event of a rub, to melt immediately at the rubbed surface whereby the metal is molten and readily displaced to allow free passage of the rubbing surface of the other member. The sealing structure includes an outer sealing layer as the proximate surface of one member and an intermediate bonding layer bonding the sealing layer to the surface of the member. The sealing layer is of a metal alloy having a melting point close to, but above the operating temperature in the impelling device and below the melting point of the surface of the one member. The bonding layer is of an alloy compatible with the sealing layer alloy and with the base metal, forms a firm bond with both the sealing layer and the base metal surface, is adapted to melt initially at a temperature lower than that of either, has a remelt temperature above the operating temperature of the impelling device, and good strength at the operating temperature. Preferably, the alloys used for the sealing and bonding layers are brazing alloys.
Sealing means for a gas impelling device including surfaces in close proximity between which there is relative movement, one surface being that of a stationary member and the other surface being that of a rotating member, comprising, a composite sealing structure including an outer sealing layer constituting the proximate surface of one member and an intermediate bonding layer bonding the sealing layer to the base surface of said one member, the sealing layer being of a metal alloy such that its melting point is close to but above the operating temperature in the impelling device and below the melting point of the other member, the bonding layer being of an alloy compatible with the alloy of the sealing layer and with the base metal and forming a firm bond with both the sealing layer and the base metal surface and being adapted to melt initially at a temperature lower than the temperature of either and having a remelt temperature above the operating temperature of the impelling device, and having good strength at said operating temperature, the sealing structure being adapted, in the event of a rub, to melt immediately at the rubbed surface whereby the metal is molten and readily displaced to allow free passage of the rubbing surface of the other member.
Claim 2
Dependent Claim
213 words
Sealing means for a gas impelling device including surfaces in close proximity between which there is relative movement, one surface being that of a stationary member and the other surface being that of a rotating member, comprising, a composite sealing structure including an outer sealing layer constituting the proximate surface of one member and an intermediate bonding layer bonding the sealing layer to the base surface of said one member, the sealing layer being of a metal alloy such that its melting point is close to but above the operating temperature in the impelling device and below the melting point of the other member, the bonding layer being of an alloy compatible with the alloy of the sealing layer and with the base metal and forming a firm bond with both the sealing layer and the base metal surface and being adapted to melt initially at a temperature lower than the temperature of either and having a remelt temperature above the operating temperature of the impelling device, and having good strength at said operating temperature, the sealing structure being adapted, in the event of a rub, to melt immediately at the rubbed surface whereby the metal is molten and readily displaced to allow free passage of the rubbing surface of the other member.
Claim 3
Dependent Claim
20 words
Sealing means, as defined in claim 1, in which the sealing structure is on the surface of the stationary member.
Claim 4
Dependent Claim
17 words
Sealing means, as defined in claim 2, in which the gas impelling device is a gas turbine.
Claim 5
Dependent Claim
23 words
Sealing means, as defined in claim 1, in which the alloys used for the sealing layer and the bonding layer are brazing alloys.
Claim 6
Dependent Claim
42 words
Sealing means as defined in claim 1, in wHich the sealing layer consists of an alloy having the following composition: Cr: 14.0 B : 3.5 Si: 4.5 Fe: 4.5 C : 0.7 Ni: balance the parts being in per cent by weight.
Claim 7
Dependent Claim
39 words
Sealing means as defined in claim 5, in which the bonding layer consists of an alloy having the following composition: Cr: 15.0 Fe: 7.0 Si: 0.75 B : 0.2 Ni: balance the parts being in per cent by weight.