Abstract: The present invention provides an acoustic particle alarm comprising a particle sensor for indicating the concentration of particles exceeding a specified size and specified concentration, for particles entrained in a fluid flow impinging on a front face of the sensor, and a nozzle for directing the fluid flow such that the particles impact the sensor in a direction substantially normal to the front face of the sensor. Each particle impacting the front face of the sensor causes a response in an output of the sensor with amplitude that is monotonic in the momentum of the impinging particle.

Abstract: The present invention provides an acoustic particle alarm comprising a particle sensor for indicating the concentration of particles exceeding a specified size and specified concentration, for particles entrained in a fluid flow impinging on a front face of the sensor, and a nozzle for directing the fluid flow such that the particles impact the sensor in a direction substantially normal to the front face of the sensor. Each particle impacting the front face of the sensor causes a response in an output of the sensor with amplitude that is monotonic in the momentum of the impinging particle.

Abstract: An improved safe is provided which offers the security of currently known more complex safes at substantially less cost. The safe preferably includes a cabinet having apertured door frame structure, with a door having inner, outer and sidewalls. Locking apparatus located within the door includes a series of selectively operable toggle mechanisms, each having a pair of pivotal links coupled to a locking bolt. The locking bolts are designed to extend through the aligned frame and door apertures to lock the door. The frame structure is formed of interconnected, seamless webs integral with the cabinet walls and presenting a recess to receive the door lip. Additional security is achieved by reinforcing the door lip with flange structure forming a part of the marginal door frame and by attaching the handle to the actuator for the toggle mechanisms so that excess force renders the handle inoperative.

Abstract: A high performance, low cost filter having a capacitor electrically connected therein to effectively block electromagnetic noise signals that are generated by certain electrical and electromechanical devices, including an electric motor, such as that commonly associated with either of the engine of a motor vehicle or a household appliance. In one embodiment of the invention, the filter is provided in combination with a fuse link that is particularly structured to have both relatively low inductance and low fusing current characteristics. The capacitor and the fuse link may be contained within a filter housing. Moreover, both the capacitor and the fuse link may be flexibly mounted within the filter housing, to thereby reduce the application of mechanical stresses and minimize the likelihood of possible damage thereto during the handling and installation of the filter.

Abstract: An acoustic communication method and system are disclosed for transmitting information through a well-bore drill string by using the acoustic noise inherently generated in the drill string by drilling operations as a "carrier" propagated therealong to be modulated by the information to be transmitted. In the drilling of wells, the action of the drill tool on the bottom of the bore hole creates acoustic noise within the drill string. Other suitable sources of "noise" are often present during "drilling operations", as broadly defined, even while bore drilling, as such, is suspended. This noise usually consists both of wide-band continuous acoustic energy and of narrow spectral lines of acoustic energy and is usually present in a variety of acoustic modes such as longitudinal and torsional acoustic waves. The detailed characteristic of this acoustic noise depends on the type of drill tool used, the drilling speed and the type of formation being drilled.