Abstract: An improved fluid pressure sensor/sensor array is shown to provide high resolution, sensitivity which can be easily controlled based on anticipated or detected pressure range, and reliable pressure measurements with easy installation and low fabrication cost. A fluid pressure sensor is provided having a substantially incompressible mounting structure with a cavity formed therein. An elastic membrane is attached to said mounting structure and across said cavity, separating the cavity from the fluid to be measured. At least one non-contact transducer is attached to the mounting structure in the cavity to detect deflection at a selected plurality of regions on the membrane. The sensitivity and pressure range of the sensor can be chosen by preselecting the elasticity of the membrane, stretching the membrane across the cavity under a preselected tension, maintaining a predetermined reference pressure in the cavity, and/or actively controlling the membrane tension.

Abstract: A water heater tank is designed to be installed within a wall to provide substantially instantaneous and continuous hot water when the faucet is activated. The tank maintains water at a hot temperature to be mixed, if necessary, with standing water from the main hot water line. The tank includes a narrow channel through which the water traverses as it proceeds through the tank. A controller calculates the appropriate mixing ratio of the water sources depending on the desired water temperature.