Vacuum insulated blast tube
AssigneeRaytheon Company
InventorsJohn Rascon, Anthony V. Formica, John Regis Leach
Life of this patent
Estimating the term…
Abstract
A vacuum insulated blast tube includes an insulating layer of a burn resistant material such as phenolic resin formed on an interior surface of the blast tube to provide the necessary erosion and thermal insulation properties to protect the blast tube and a vacuum insulated layer formed in the walls of the blast tube itself to provide the additional thermal insulation properties to protect any non-propulsive sub-systems positioned in the void space around the blast tube. A void space in the walls of the blast tube is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form the vacuum insulation layer.
Claims20
A vacuum insulated blast tube, comprising:
- a hollow blast tube shell defining a void space therein along a length of the shell;
- and
- an insulating layer formed of a burn resistant material on an interior surface of the shell,
- wherein the void space is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form a vacuum insulation layer.
A vacuum insulated blast tube, comprising:
- a hollow blast tube shell defining a void space therein along a length of the shell;
- and
- an insulating layer of phenolic resin having a thermal conductivity Tcond_phenolic on an interior surface of the shell,
- wherein the void space is held under vacuum with a pressure of less than 10−3 Torr and a thermal conductivity Tcond_vac of less than one-fifth of the thermal conductivity of air Tcond_air to form a vacuum insulation layer, wherein Tcond_vac is less than one-two hundredth the thermal conductivity of the phenolic resin Tcond_phenolic.
A rocket motor, comprising:
- a cylindrical rocket motor casing having a diameter D1;
- a combustion chamber including a propellant positioned in the cylindrical rocket motor casing;
- a nozzle positioned aft of the combustion chamber to expel hot gases resulting from combustion of the propellant;
- a vacuum-insulated blast tube that couples the combustion chamber to the nozzle, said blast tube having a diameter D2<D1 that defines a first void space between the blast tube and the rocket motor casing;
- one or more sub-systems positioned in the first void space,
- wherein the vacuum-insulated blast tube comprises,
- a hollow blast tube shell defining a second void space therein along a length of the shell;
- and
- an insulating layer formed of a burn resistant material on an interior surface of the shell that erodes as hot gases pass through the blast tube and protects the blast tube from elevated temperatures,
- wherein the second void space is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form a vacuum insulation layer to provide additional thermal insulation to thermally insulate the one or more sub-systems.
Dependencies are inferred from the claim text.