Abstract: A device for detecting tampering with standard mechanical locksets has a pair of electrical contacts placed within the recess that receive lock's bolt and a third conductor positioned to run vertically along the door frame. A control box sends a low-level radio frequency (RF) signal to the first contact that in turn energizes the entire lockset when the bolt is in its extended position. The second contact returns RF energy to the control box to signal that the bolt is in its extended or locked position. Measured changes in capacitance serve to automatically enable tamper detection when the lockset is in its locked position; further, to automatically signal an alarm when the locked lockset is tampered with, to automatically disable tamper detection when the lockset is in its unlocked position and to define one or more protected areas whose status may then be signaled through conventional multi-zone security systems.

Abstract: A multi-stage treatment system for infectious waste includes a shredding stage, a granulating stage, a wetting stage, a disinfecting stage, and a dewatering stage which define a continuous treatment flowpath for the infectious waste. A plurality of blades shred the waste in the shredding stage, then the waste is injected with volatile disinfectant chemicals which are mixed immediately before injection. A plurality of blades in a granulating stage then fragment the waste to a smaller particle size. The granulating stage insures that the waste is granulated to a sufficiently small size to facilitate the use of a relatively low concentration of a highly reactive disinfectant. Chemicals are mixed to form a volatile, highly reactive disinfectant which is then immediately injected into the waste downstream of the shredding stage. A plurality of jets wet the waste mixture in the wetting stage with the heated aqueous disinfectant.

Abstract: A multi-stage treatment system for infectious waste includes a shredding stage, a granulating stage, a wetting stage, a disinfecting stage, and a dewatering stage which define a continuous treatment flowpath for the infectious waste. A plurality of blades shred and then granulate the waste in the shredding and granulating stages while simultaneously mixing the waste with disinfectant chemicals. The granulating stage insures that the waste is granulated to a sufficiently small size to facilitate the use of a relatively low concentration of a highly reactive disinfectant. Chemicals are mixed to form a volatile, highly reactive disinfectant which is then immediately injected into the waste stream. A plurality of jets wet the waste mixture in the wetting stage with the heated aqueous disinfectant. A flow restriction removes excess aqueous liquid from the disinfected waste in the dewatering stage and renders the product suitable for landfilling.

Abstract: A control system for regulating the decontamination of waste in a reaction chamber is provided. The control system monitors the chamber temperature and disinfectant concentration. Using the disinfectant concentration, the control system then calculates the minimum temperature required to maintain a specified level of decontamination. This minimum temperature is then compared to the actual temperature by the control system. If the actual temperature is below the minimum, the control system operates a heater to heat the reaction chamber. Additional temperature control can also be provided by the control system. If desired, the control system compares the actual chamber temperature to an ideal operating temperature. If the actual temperature exceeds the ideal temperature, the system cools the chamber by pumping in additional low temperature disinfectant. In this manner, the additional disinfectant maintains the level of decontamination as the chamber temperature decreases.

Abstract: A method and apparatus for continuously monitoring the concentration of a target chemical in a solution, such as chlorine dioxide in sewage or waste water, includes a holding tank, a bubbler chamber, and an air pump for directing air bubbles through the solution held in the bubbler chamber. Gases discharged from the solution by the air bubbles are collected in the bubbler chamber. These discharged gases include a quantity of the target chemical present in the solution as a dissolved gas. The concentration of the chemical in the discharged gases is then measured with a sensor such as a polarographic probe. This concentration along with the measured temperature of the solution is used as an analog to determine the concentration of the chemical in the solution.

Abstract: An infectious waste, a solid chlorite salt, a solid acid and a preheated aqueous solvent are mixed in a treatment volume. At least a portion of the chlorite salt and acid is dissolved in the preheated aqueous solvent incident to mixing and is reacted to form a treatment solution containing a chlorine dioxide disinfectant and a byproduct acid salt. The infectious waste is contacted with the chlorine dioxide in the treatment solution which attacks and destroys the infectious constituents of the waste, thereby decontaminating the waste. Upon dewatering, the decontaminated waste is suitable for landfilling. Process control is exercised by controlling the temperature of the aqueous solvent. A solvent temperature is selected which optimizes both the chlorine dioxide concentration in the treatment solution and the reactivity of the chlorine dioxide with the infectious constituents.

Abstract: A device for pumping fluid through a resilient tube has a platen for holding the tube and a pumping mechanism for squeezing the tube against the platen. The pumping mechanism includes a first pumping finger which squeezes the tube at a first location and a second pumping finger which squeezes the tube at a second location. For their respective alternating pumping actions, the first finger is configured and operated to displace approximately twice the fluid volume displaced by the second pumping finger. A valve means is also mounted on the base and is positioned to alternately occlude the tube upstream from the first and second pumping fingers during the pumping action of the first pumping finger and to occlude the tube between the first and second locations upstream from the second pumping finger during the pumping action of the second pumping finger.

Abstract: A drive mechanism for actuating the fingers of a peristaltic pump has a base, and a drive member reciprocally mounted on the base. A jointed arm is pivotally attached at one end to the drive member and at the other end to a fixed point on the base. A rotary cam actuator is mounted on the base to urge against the arm to reciprocate the drive member.

Abstract: A method for sterilizing infectious waste includes placing the waste in a disposal apparatus which has an isolated volume for holding the waste. A dry granulated medium which has a disinfectant constituent is also placed within the isolated volume along with the waste. When the disposal apparatus is activated, an atomized mist is introduced into the volume and the waste, the medium, and the moisture in the mist are thoroughly blended together. The resulting destroyed waste is thoroughly moistened with the disinfectant solution which is formed by the mist and the disinfectant constituents of the medium. Then, the moistened, destroyed waste is heated to a predetermined temperature for a predetermined time to ensure efficacious sterilization of the waste.

Abstract: A method and apparatus are disclosed for monitoring the contents of a container in order to detect when the contents are below a predetermined level. An optical metering signal from a light source driven by a multivibrator is projected at a predetermined level across the space within the container. A light sensor on the opposite side of the space within the container detects incident illumination there. The metering signal is incident there only when the contents of the container are below the predetermined level. Otherwise, the contents either block or refract the metering signal from its normal path, and the metering signal goes undetected. A unity gain amplifier of variable sign coupled to the light sensor and to the multivibrator determines when signal from the light sensor are synchronized with the output of the multivibrator, so as to be deemed to correspond to pulses of the metering signal.

Abstract: A highly efficient switching regulator for a field effect transistor employed in a regulated power supply as the switching element for an unregulated power source. The emitters of a pair of complementary control transistors are coupled to the gate of the field effect transistor, while the bases of each of the control transistors are coupled to a driver circuit. The driver circuit includes a switch operated by a control unit that senses the level of the output voltage of the regulated power supply and constant current circuit. The control transistors are connected for Class C operation, so that only one control transistor is conductive at any time. A charging capacitor charged from the unregulated voltage source is coupled to the gate of the field effect transistor when one of the control transistors is conductive, causing the field effect transmission to be conductive.

Abstract: A thermal discriminator including two temperature sensitive switching devices having substantially identical electrical characteristics and exhibiting regenerative switching at a power level which is dependent on the temperature sensed by the switching devices. Both switching devices are exposed to the same ambient temperature in a surrounding medium but only one of them is exposed to variations in the heat exchange properties of the surrounding medium. Sufficient power is applied to both switching devices from an increasing voltage source to cause the switching devices to dissipate about the same amount of heat under certain conditions of the medium so that both switching devices would normally switch substantially simultaneously.

Abstract: The apparatus includes two temperature sensitive switching devices having substantially identical electrical characteristics and exhibiting regenerative switching at a power level which is dependent on the temperature sensed by the switching devices. Both switching devices are exposed to the same ambient temperature in a surrounding medium but only one of them is exposed to variations in the heat exchange properties of the surrounding medium. Means are provided for applying D.C. power to both switching devices at a level such as to maintain them below their switching point under preset conditions of the medium. A coupling device is interconnected between the two switching devices for inducing regenerative switching in one of the switching devices in response to unbalance in the heat dissipated by the switching devices due to variations in the heat exchange properties of the surrounding medium from the preset conditions.

Abstract: An adjustable temperature actuated switching apparatus using a fixed transition type negative temperature coefficient device is disclosed. Such device exhibits regenerative switching at a predetermined temperature and power level and a monotonic shift in the power level required to induce regenerative switching, this shift being a function of ambient temperature at the device. The apparatus comprises means for passing a controlled current through the device to thermally bias the same so as to make it switch at a desired ambient temperature at the device below its transition temperature, and means for detecting regenerative switching of such device as an indication that the desired temperature at the device has been reached. The source of controlled current may be a D.C. or an A.C. source.

Abstract: An analog memory system is disclosed which uses a temperature sensitive device exhibiting a significant hysteresis centered about a predetermined transition temperature and a significant impedance change about such transition temperature to allow discrimination of a large number of identical temperature impedance levels with conventional electronic circuitry. The memory system comprises means for adjusting the temperature of such temperature sensitive device to write-in an input signal in the form of a predetermined impedance of said temperature sensitive device, means for subsequently adjusting the temperature of said temperature sensitive device at such transition temperature to store the input signal, and a converter for accurately converting the impedance of the temperature sensitive device to an analog of the signal stored in the memory system.

Abstract: A temperature control circuit is disclosed for controlling the firing angle of a thyristor such as a silicon controlled rectifier connected in series with a heater across an alternating power source. The control circuit comprises a field effect transistor having its source and drain electrodes connected for firing of the rectifier when the field effect transistor is rendered conductive, and a bias phase control connected to the gate of the field effect transistor for generating a fixed A.C. voltage component which is phase shifted by about 90.degree. with respect to the voltage of the power source together with a temperature dependent D.C. voltage component to control the firing angle of the silicon controlled rectifier in accordance with the heat generated by the heater, the sum of the A.C. and D.C. voltage components being fed to the gate of the field effect transistor. The temperature dependent D.C.

Abstract: A semi-conductor thermal protection arrangement is disclosed for use with class AB, B, or C power amplifiers or in any other circuit configuration wherein a reduction in drive signal at a stage prior to that of the protected semi-conductor results in a lessening of the protected semi-conductor dissipation. The arrangement comprises a temperature sensor thermally coupled with the protected semi-conductor for detecting the absolute temperature of the semi-conductor and electrically connected so as to reduce the drive signal of the semi-conductor when the temperature of such semi-conductor exceeds a predetermined temperature above the normal operating temperature of the semi-conductor.

Abstract: A temperature discrimination apparatus is disclosed which comprises a first switching device exhibiting regenerative switching action at a power level which is dependent on the temperature sensed by such first switching device, a second switching device exhibiting regenerative switching action solely in response to a pre-selected power level, means connected to the first and second switching devices for determining if the first switching device has switched before the second switching device in the cycle of the a.c. power source as the magnitude of the voltage increases from zero. This will serve as an indication that the temperature to be sensed has been reached.