Abstract: Disclosed, in one general aspect, is a boiler controller that includes an input for receiving a boiler water level signal, a screen having a data display that displays information. The data display includes an alphanumeric status indicator area responsive to the water level signal and operative to display status information about the water level signal in alphanumeric format, and a background indicator that extends around the alphanumeric status area and is operative to display a visual treatment that communicates different boiler safety levels. Disclosed in another general aspect is a boiler controller that includes an input for receiving a boiler water level signal and a compound level indicator that includes a vertically extending level-indicating device, a baseline reference level indicator positioned along the vertically extending level level-indicating device, and a visual treatment for the vertically extending level-indicating device that communicates different boiler safety levels.

Abstract: Disclosed in one aspect is an echo-ranging sensor system that gives reliable and accurate measurements when used in high-temperature(s), high-pressure(s), and over all hostile environment(s). An example of a novel application is for sensing, monitoring, and controlling water level measurement in boilers where the environment is extremely challenging and caustic. Although disclosed systems are not limited to the ultrasonic frequency range, many applications in which they will most likely be used would work best with transducers that operate at ultrasonic frequencies. This disclosure includes a robust and optimized mechanical and electronic design for mounting, and a design for transducers that are thermally matched and allow transmission and reception of energy with precision in harsh environments and can also be used with a controller. The system performs in high-temperature, high-pressure, and can withstand extreme conditions, such as boiling water, steam, and other gaseous substances and caustic chemicals.

Abstract: An electronic scoring apparatus for use in a plurality of dart games, which apparatus minimizes a user's mathematical calculations, thus keeping scoring errors to a minimum and avoiding tedious mental calculations. The apparatus includes input switches to input data, lighted displays which inform the user, and selection input switches by which the user selects and customizes a plurality of games and enters scoring information. The apparatus is provided with displays which inform users and spectators of game circumstances. The apparatus suggests targets at which to throw, in response to game situations. Games can be played versus the apparatus at various selected skill levels. A plurality of games can be played with more than two teams. Lighted displays portray characters historically used in the dart game of Cricket.