Heat units using a solid fuel capable of undergoing an exothermic metal oxidation-reduction reaction propagated without an igniter

Inventors

Sharma, Krishnamohan • Lei, Mingzu

Assignees

Alexza Pharmauceticals Inc • Alexza Pharmaceuticals Inc

Abstract

A heating unit comprising an electrically conductive substrate. A solid fuel layer comprising a metal reducing agent, a metal containing oxidizing agent and a binder is coated on a surface of the substrate, the solid fuel layer having a solid fuel surface spaced from the substrate. A first electrode coupled to the substrate. A second electrode coupled to the solid fuel surface. A power supply is configured to be selectively coupled to the first and second electrodes to provide a voltage between the metallic substrate and the solid fuel surface. The voltage acts to propagate an exothermic metal oxidation-reduction reaction without the use of an igniter.

Core Innovation

The disclosed invention relates to an igniter-free heat unit and a drug supply unit that uses an electrically conductive substrate with an interior-coated solid metal oxidation-reduction fuel layer. The solid fuel layer includes a metal reducing agent, a metal containing oxidizing agent, and an inorganic binder, and is electrically coupled to electrodes so that selective energization propagates an exothermic metal oxidation-reduction reaction without an external starter.

A drug layer capable of vaporization upon being heated to a select temperature is provided on the exterior surface of the electrically conductive substrate. Selective electrical energization provides 9 volts or higher between the electrically conductive substrate and a solid fuel surface to heat the fuel layer and thereby heat the drug layer to its select temperature for vaporization.

The disclosed structures and configurations support multiple ways of providing ignition without an igniter, including electrode and substrate arrangements with a single substrate-fuel layer, sandwiched conductive substrates, and multiple discrete fuel layers that can be selectively engaged. The document further describes constraints related to fuel resistance and activation behavior, and it states that the approach enables vaporization of drug films to form aerosols within sub-second timescales after ignition.

Claims Coverage

The document provides one independent claim, covering a drug supply unit with an electrically conductive substrate, an interior-coated solid fuel layer containing a metal reducing agent, a metal containing oxidizing agent, and an inorganic binder, an exterior drug layer that vaporizes when heated, and an electrode/power supply arrangement that applies 9 volts or higher between the conductive substrate and the solid fuel surface.

Overall, the claim coverage centers on coupling selective electrical energization between a conductive substrate and an interior-coated metal oxidation-reduction solid fuel layer to heat a vaporize-capable drug layer on the exterior surface, with the independent claim requiring at least 9 volts between the substrate and the solid fuel surface.

Stated Advantages

Documented Applications