Abstract: A liquid level detection device includes a signal source for generating one or more unique signals on low impedance signal electrodes, a lock-in amplifier, and a reference signal directly connecting the signal source to the lock-in amplifier. The unique signals generated by the signal source are connected to one or more low impedance signal electrodes. The low impedance signal electrodes may be positioned at different levels inside the tank so that at any given level of liquid in the tank, each low impedance individual electrode may or may not be in contact with the liquid in the tank. Alternatively, the low impedance signal electrodes may be attached to the external wall of the tank at different levels. An antenna is connected to an input of the lock-in amplifier. The antenna may be placed inside the tank at the lowest level for the liquid, or the antenna may be attached to the outside wall of the tank near the bottom of the tank.

Abstract: A liquid handling system having a tank with a centrifugal pump for pumping the liquid out of the tank is disclosed. The centrifugal pump is located beneath tank and has a coaxial inlet-outlet. Capacitive sensors are used to detect the level of liquid in the tank, and control circuits are connected to the capacitive sensors and control the operation of the pump.

Abstract: A condensate pump for an HVAC system includes a reservoir for collecting condensate water, a pump motor connected to an impeller pump for pumping the condensate water out of the reservoir, and a floatless pump control module. The floatless pump's microcontroller detects the water level in the reservoir and, based on the water level in the reservoir, controls the operation of the pump motor, and if necessary, sounds an alarm and shuts down the HVAC system. The floatless pump microcontroller may employ an ultrasonic transducer or capacitance sensors to detect the level of condensate water in the reservoir. The microcontroller implements a variable water lift feature to pump the water using the lowest possible speed for the pump. The microcontroller implements a self-cleaning feature to pump stagnant water out of the reservoir and to pulse water in the drain line and the agitation of the water in the reservoir.

Abstract: A condensate pump for an HVAC system includes a reservoir for collecting condensate water, a pump motor connected to an impeller pump for pumping the condensate water out of the reservoir, and a floatless pump controller. The floatless pump controller detects the water level in the reservoir and, based on the water level in the reservoir, controls the operation of the pump motor, and if necessary, sounds an alarm and shuts down the HVAC system. The floatless pump controller may employ an ultrasonic transducer or capacitance sensors to detect the level of condensate water in the reservoir.

Abstract: A condensate pump for an HVAC system includes a reservoir, a solenoid pump assembly with a solenoid pump, and a solenoid pump electronic control module for limiting the amount of energy delivered to the solenoid pump during one half cycle from an AC current source. The solenoid pump is mounted in the solenoid pump assembly by means of shock absorbing material, and the solenoid pump assembly is mounted on a support member with shock absorbing material interposed between the solenoid pump assembly and the support member.

Abstract: A service gauge for determining refrigerant pressure and the saturated vapor equivalent temperature, or other parameters, for a refrigerant in an HVAC system. In one embodiment, the service gauge employs a bourdon tube with at least one attached strain gauge to sense the refrigerant pressure and produce an electronic pressure signal. In another embodiment, a magnet and rotary position sensor produces an electronic signal proportional to the refrigerant pressure. The electronic pressure signal from the output of the strain gauge or the rotary position sensor is connected to a microprocessor, which calculates and displays the refrigerant pressure, the saturated vapor equivalent temperature for a variety of refrigerants, produces instantaneous and time lapsed representations of those parameters, and other parameters of the refrigerant.

Abstract: A condensate pump for an HVAC system includes a reservoir for collecting condensate water, a pump motor connected to an impeller pump for pumping the condensate water out of the reservoir, and a floatless pump controller. The floatless pump controller detects the water level in the reservoir and, based on the water level in the reservoir, controls the operation of the pump motor, and if necessary, sounds an alarm and shuts down the HVAC system. The floatless pump controller may employ an ultrasonic transducer or capacitance sensors to detect the level of condensate water in the reservoir.

Abstract: A condensate pump for an HVAC system includes a reservoir for collecting condensate water, a pump motor connected to an impeller pump for pumping the condensate water out of the reservoir, and a floatless pump controller. The floatless pump controller detects the water level in the reservoir and, based on the water level in the reservoir, controls the operation of the pump motor, and if necessary, sounds an alarm and shuts down the HVAC system. The floatless pump controller may employ an ultrasonic transducer or capacitance sensors to detect the level of condensate water in the reservoir.

Abstract: A condensate pump for an HVAC system includes a reservoir for collecting condensate water, a pump motor connected to an impeller pump for pumping the condensate water out of the reservoir, and a floatless pump control module. The floatless pump's microcontroller detects the water level in the reservoir and, based on the water level in the reservoir, controls the operation of the pump motor, and if necessary, sounds an alarm and shuts down the HVAC system. The floatless pump microcontroller may employ an ultrasonic transducer or capacitance sensors to detect the level of condensate water in the reservoir. The microcontroller implements a variable water lift feature to pump the water using the lowest possible speed for the pump. The microcontroller implements a self-cleaning feature to pump stagnant water out of the reservoir and to pulse water in the drain line and the agitation of the water in the reservoir.

Abstract: A noninvasive security device for detection of blocked fluid flow within a conduit includes clamping body that may be affixed to the conduit and a safety overflow circuit mounted to the clamping body. The safety overflow circuit includes first and second sensor pads that act as the metal plates of a capacitor. The sensor pads are connected to the clamping body and positioned proximate the conduit to measure the capacitance within the conduit. The capacitance will be low when water is freely flowing through the conduit, since the dielectric constant will be similar to that of air. However, when the water level increases in the conduit, the dielectric constant will increase as will the capacitance, such that a pulse signal is generated to notify the user of the occlusion and to further disable the source of the water to the conduit.

Abstract: A two-piece plastic equipment pad with a top portion and an identical bottom portion. Each portion has a base with an underlying grid structure comprising cells formed by perpendicular ribs. The top portion and the bottom portion are aligned and connected together by connector strips that slots formed in the perpendicular ribs of the grid structure of the top portion and the bottom portion.

Abstract: A service gauge for determining refrigerant pressure and the saturated vapor equivalent temperature, or other parameters, for a refrigerant in an HVAC system. In one embodiment, the service gauge employs a bourdon tube with at least one attached strain gauge to sense the refrigerant pressure and produce an electronic pressure signal. In another embodiment, a magnet and rotary position sensor produces an electronic signal proportional to the refrigerant pressure. The electronic pressure signal from the output of the strain gauge or the rotary position sensor is connected to a microprocessor, which calculates and displays the refrigerant pressure, the saturated vapor equivalent temperature for a variety of refrigerants, produces instantaneous and time lapsed representations of those parameters, and other parameters of the refrigerant.

Abstract: A pressure gauge for determining refrigerant pressure and the saturated vapor equivalent temperature for a refrigerant in an HVAC system. The pressure gauge employs a bourdon tube with at least one attached strain gauge to sense the refrigerant pressure and produce an electronic pressure signal. The electronic pressure signal from the output of the strain gauge is attached to a microprocessor, which calculates and displays the refrigerant pressure, the saturated vapor equivalent temperature for a variety of refrigerants, and produces instantaneous and time lapsed representations of those parameters.

Abstract: A condensate pump for an HVAC system includes a reservoir, a solenoid pump assembly with a solenoid pump, and a solenoid pump electronic control module for limiting the amount of energy delivered to the solenoid pump during one half cycle from an AC current source. The solenoid pump is mounted in the solenoid pump assembly by means of shock absorbing material, and the solenoid pump assembly is mounted on a support member with shock absorbing material interposed between the solenoid pump assembly and the support member.

Abstract: A tie for insulated concrete forms that has a Z-bend configuration so that the tie is nestable with similar Z-bend ties in order to optimize the cubic volume and the weight of a container of nested ties for shipment.

Abstract: A cooler having an integrated seat assembly, includes a cooler body which can have one or more compartments. The cooler body is coupled with a seat assembly bracket by a coupling means, such as a hinge. Seat backs are integrally formed in one sidewall of the cooler body and seat bottoms are formed on the bracket, such that when the bracket is opened, it forms a seat with the seat backs. The bracket can be folded up flat against the cooler in a closed and locked position, for easy storage or transportation.

Abstract: A safety switch for sensing the level of water in a condensate pan has a molded plastic body with an attachment section and a float probe. The attachment section includes a collar that fits over and connects to the side edge of the condensate pan. The float probe comprises a hollow elongated housing with a grille opening to allow entry of water. A float, position within the hollow elongated housing, moves in response to entry of water into the elongated housing. The float includes a magnet that activates a reed switch mounted in a watertight compartment extending along one wall of the elongated housing. The float probe may be fixedly or adjustably attached to the molded body of the safety switch. For adjustable attachment, the float probe is snugly fit into the opening of a yoke so that the float probe can be raised or lowered or inclined with respect to the yoke.