Abstract: A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface area of the capacitor plates, the dielectric properties of the fluid increase the capacitance of the cell proportionally. The plates are connected to an oscillator whose output frequency varies with the change in container fluid levels. By monitoring these frequency changes, the container fluid levels of the fluid in the container can be controlled.

Abstract: An air filter and particle removal system for eliminating impurities from air. The system is constructed with an upper electrode plate facing a lower electrode plate. A flypaper-like material is placed close to the lower plate with the sticky side of the material facing the upper plate. The plates have different voltage polarities so that when air is passed through the duct, charged particles within the air will move toward the lower plate and are caught by the flypaper-like material. Further, the upper plate is shaped to create turbulences in the air to cause other impurities to flow over and be caught by the flypaper-like material.

Abstract: A laser soldering system wherein a plurality of laser beams are simultaneously directed to a plurality of spatially separate locations on a printed circuit board for simultaneously soldering. Each of the laser beams is formed by combining the outputs of a plurality of fiber cables, each of which is connected to an individual laser diode.

Abstract: An ultrasonic grade and auger control for use on a road paving machine to compensate for uneven road surfaces is described. As the road paving machine travels, asphalt is centrally deposited along the road bed. An auger is connected to the back of the road paving machine and contains a series of spiral blades which moves the asphalt away from the center of the road bed toward its outer edges. The ultrasonic auger control apparatus detects the height of the asphalt positioned at the outer edges of the paving machine and regulates the speed of the auger to provide even distribution of the asphalt. A screed is located behind the auger to uniformly place and pack the paving material. The ultrasonic grade control apparatus regulates hydraulic actuators which control the thickness of the new road surface by adjusting the height of the screed.

Abstract: An X-ray tube exposure monitor for recording the emissions from a diagnostic X-ray tube. A photo diode is mounted inside the X-ray tube bulkhead and detects radiation from the X-ray tube. The photo diode is connected to a high gain amplifier and, in response to radiation being detected, the output of the amplifier sends an electronic signal to a microprocessor. The microprocessor records the emission duration and the temperature of oil around the X-ray tube and increments an exposure count. The recording and exposure count is stored in non-volatile memory which is read later by a service technician.

Abstract: A method and apparatus for regulating a microwave oven to a predetermined output power level. The anode current or a voltage corresponding to it is monitored to provide a signal indicative of the actual output power of the magnetron. Time is divided into a sequence of equal time intervals, each interval corresponding to fixed number of ac line cycles. In accordance with the signal, the number of ac cycles to be supplied to the power supply for each interval to regulate the output power towards the regulated level is determined. The determined number of cycles are supplied by switching at the zero current crossings between the line and the power supply. The switching is executed so that the supplied ac cycles are distributed substantially uniformly over the particular time interval.

Abstract: A microprocessor controlled microwave oven having a scale for providing a signal corresponding to the weight of a food body in the cavity to the microprocessor. Through a control panel, the operator inputs a second signal corresponding to the initial temperature of the food body. From these signal inputs, the microprocessor calculates the microwave exposure time period to raise the temperature of the food body to a predetermined temperature or to cook the food body. In accordance with the time period, the microprocessor then controls the magnetron through one or more active cycles as selected.

Abstract: A heat exchanger for efficiently transferring heat from a first fluid body to a second fluid body within a selected container, tank or reservoir, comprising an elongated tubular hoselike plastic body of deformable material wrapped around the container and filled with the first heated fluid, the plastic body being deformable under the pressure of the first fluid so as to conform to the exterior surface of the container whereby more efficient transfer of heat between the fluids is achieved.

Abstract: A bulkhead fitting for use with plastic material for conducting fluid through an aperture in the material and comprising coupling components on either side of the material which interfaces with the plastic material by an abrasive element pressed against the plastic material by an intermediate compressible member whereby leakage is prevented.