Abstract: A monitoring apparatus for pressure sensitive devices is provided which detects the operating state of the monitored device, and which is designed to provide a reliable output even when operated in hostile, corrosive environments. The monitoring apparatus preferably includes a light source for transmitting a beam of light along a path of travel proximal to the monitored device, a light detector for detecting the light beam, and a member for adjusting the path of travel of the light beam in response to the actuation of the pressure sensitive device. Several alternative embodiments are disclosed.

Abstract: An improved construction is provided for fluid pressure responsive electrical switching apparatus, which achieves physical miniaturization, quick response time, sensitivity to relatively low levels of change or differential in fluid pressures, adaptability for employment in corrosive environments and under a very wide range of temperature conditions, simplicity and economy of fabrication and assembly, reliability of operation and general versatility for utilization in diverse applications. The improved apparatus involves, besides suitable housing structure that may provide for installation accommodating to various pressure and other conditions dictated by the application, a thin, wafer-like laminated switch assembly peripherally sealed in the housing structure and disposed for direct fluid communication with the fluid whose pressure is to be monitored for the purpose of controlling actuation of the switch assembly.

Abstract: Nozzle structure particularly adapted for use with pressurized fire suppressants is disclosed which includes an elongated, tubular, apertured body, and a visible, easily replaceable, fluid flow-directing slug disposed therein for controlling and directing lateral fluid flow from the nozzle. The slug is located in partial or complete blocking relationship to certain of the body sidewall apertures so as to define therewith outlet ports of desired effective dimensions and to control the spray patterns emanating therefrom. Use of a slug of different configuration serves to alter nozzle performance, discharge direction and discharge rate without need for any additional modifications of the nozzle. The annular end wall of the body allows the adjacent end face of the slug to be seen, such that appropriate coding can be applied to the slug end face for easy determination of the design discharge rate of the nozzle.