Explosion-proof acoustic source for hazardous locations

An explosion-proof system for generating airborne acoustic energy, comprising:

• a main housing including an open housing space and an opening;
• a cover structure configured for removable attachment to the main housing to cover the opening and provide an explosion-proof housing structure, the cover structure including an integral head mass having a front face, the cover structure and head mass forming a one-piece unitary structure having an inside surface and an outside surface from which the head mass protrudes, the explosion-proof housing structure configured to contain any explosive condition within the housing structure and prevent such condition from igniting an environment surrounding the housing structure;
• a Tonpilz acoustic transducer including a tail mass, a piezoelectric excitation assembly, and said head mass, said tail mass and said piezoelectric excitation assembly attached to the inside surface of the cover structure and configured to be disposed within said explosion-proof housing structure with the cover structure attached to the main housing, the head mass disposed outside the explosion-proof housing structure, with the piezoelectric excitation assembly sandwiched between the head mass and the tail mass by a stress bolt;
• a power source disposed within said explosion-proof housing structure;
• an electronic circuit disposed within said explosion-proof housing structure powered by the power source and electrically coupled to the piezoelectric excitation assembly, the electronic circuit configured to generate a drive signal for driving the piezoelectric excitation assembly to cause the Tonpilz transducer to resonate and generate airborne acoustic energy from the front face of the integral head mass;
• the outside surface of the cover structure further characterized as being uninterrupted by any openings;
• and
• wherein the cover structure and head mass are formed of a first, lightweight metal, and the tail mass is fabricated of a second metal different from the first metal, and wherein the second metal is heavier than the first metal;
• and
• wherein the power source is a rechargeable battery, and the main housing includes a battery charging port for electrical connection to a battery charger in a charging mode, the battery charging port revealed by removal of a threaded plug which seals the port.