Abstract: A wireless sensor assembly for monitoring conditions in an ambient environment, such as for use in a climate control system for a data center is disclosed. The sensor assembly has a small form-factor housing extending along a longitudinal axis and defining an interior space. A sensor circuit is disposed within the housing and includes at least one sensor element for detecting temperature and/or humidity that is enclosed within a vented sub-chamber of the housing. A mounting member forming part of an exterior surface of the housing mounts the sensor assembly vertically along the at an installation location within an ambient environment being monitored.

Abstract: A thermal switch assembly includes a dielectric spacer and a switch blade member of shape memory metal sandwiched between a pair of flat metal plates. The spacer provides a cavity between the plates and the switch blade member has a switch blade portion projecting into the cavity. The switch blade member has a mounting portion engaging one of the metal plates, and the switch blade portion normally is under bending stress in engagement with the other metal plate to provide a current path between the plates. At elevated temperatures, the switch blade portion of shape memory metal moves out of engagement with the other metal plate to interrupt the current path. Fasteners integral with the dielectric spacer cooperate with the metal plates and the switch blade member to hold the switch assembly together with the spacer and the mounting portion of the switch blade member compressively sandwiched between the metal plates.

Abstract: A thermal switch having a current carrying switch blade actuator of shape memory metal has a resistance less than 20 milliohms and a contact force greater than 150 grams. The actuator is deformed to less than about 8% strain, and a very hard high strength dielectric material is used for a spacer.

Abstract: A protective PTC device is heated by a heater PTC device or by a resistor to an elevated temperature greater than ambient but less than its switching temperature. The elevated temperature of the protective PTC device reduces its switching response time, and minimizes variations in such response time with variations in ambient temperature. The protective PTC device is connected in series with an electrical load to reduce current to a load when the protective PTC device is switched to its high-resistance state by a temperature increase resulting from overcurrent. The heater PTC device or the heater resistor may be in parallel or in series with the protective PTC device. The heater PTC device does not carry load current, but the heater resistor may be placed in series with the load and the protective PTC device so as to carry load current along with the protective PTC device.

Abstract: Positive temperature coefficient thermistors are mounted in heat transfer relationship to a support member of a material that is pervious to light. The thermistors are positioned on the support member to provide a large unobstructed area through which light may pass. The self-limiting nature of the thermistors eliminates the need for a separate temperature responsive heater control switch. The heater is useable for heating liquid crystal displays, and allows back lighting of such displays by a light source positioned on the opposite side of the heater from the display.

Abstract: A sealed bimetal snap disc thermostat is disclosed which is suitable for use in environmental locations in which severe thermocycling occurs. The thermostat provides a disc cup having an imperforate end wall which is the only portion of the thermostat per se which is exposed. A non-metallic enclosure cup is formed with an aperture closely encircling the disc cup and which defines a cavity surrounding the remaining portions of the thermostat. A sealing compound, such as epoxy, fills such cavity. The disc cup is crimped onto the thermostat body and provides an extended portion which is spaced from the thermostat body so that the sealing adhesive provides an interface of substantial area with the metal disc cup to assure a continuing seal. Because the sealant and enclosure cup surround the entire thermostat except for the disc cup, the thermostat is thermally insulated from its environment except for the disc cup end face.

Abstract: A fiber optics condition sensor and a method of producing such a device is disclosed. A bundle of optical fibers provides a planar termination on one end and is bifurcated to provide one group adapted to be connected to a light source and another group adapted to be connected to a detector. A shallow, curved, thin metallic diaphragm provides a central portion movable toward and away from the termination in response to the condition being sensed in order to vary the light reflected to the detector and therefore produce a detector output signal which is a function of the changes in conditions being sensed. The diaphragm may be formed of bimetal for sensing temperature conditions, or of a homogeneous metal to sense pressure.