A heating bulb for a liquid boiler includes a metal pressure shell of titanium or the like and contains an inner pressure plenum that stores pressurized inert gas, such as argon. The inner pressure plenum is sealed with a ceramic isolation plug that also contains a power conduit supplying a resistance heating element within the inner pressure plenum. Preferably, from approximately five to 100 atmospheres of pressure may be used to make the heating of the pressurized inert gas more efficient for heating a liquid within a boiler into which the heating bulb is placed. Thermocouples are used to control the flow of power to the resistance heating element.

A heating bulb for a liquid boiler includes a metal pressure shell of titanium or the like and contains an inner pressure plenum that stores pressurized inert gas, such as argon. The inner pressure plenum is sealed with a ceramic isolation plug that also contains a power conduit supplying a resistance heating element within the inner pressure plenum. Preferably, from approximately five to 100 atmospheres of pressure may be used to make the heating of the pressurized inert gas more efficient for heating a liquid within a boiler into which the heating bulb is placed. Thermocouples are used to control the flow of power to the resistance heating element.

A double-ended high intensity discharge lamp includes a luminous tube which comprises an inner tube and an outer tube. At least one electrical member is securely fastened inside the luminous tube and at least one illuminator supported inside the luminous tube with a distributor connected with the electrical member to receive power and supply the illuminator. The outer tube is another protective shield to stop spreading in explosion of the illuminator.

A double-ended high intensity discharge lamp includes a luminous tube which comprises an inner tube and an outer tube. At least one electrical member is securely fastened inside the luminous tube and at least one illuminator supported inside the luminous tube with a distributor connected with the electrical member to receive power and supply the illuminator. The outer tube is another protective shield to stop spreading in explosion of the illuminator.