A pocket size laser power meter adapted to measure the power of laser energy emitted by a laser. The power meter includes a thermal mass adapted to receive the laser energy. A temperature sensor coupled to the thermal mass translates temperature changes in the thermal mass into an electrical sensor signal having a variable voltage. A differentiator coupled to the temperature sensor receives the electrical sensor signal and produces a differentiated signal indicative of the rate of change of voltage of the electrical sensor signal. A cooling rate holding circuit coupled to the differentiator receives a cooling portion of the differentiated signal indicating a lowering of the temperature of the thermal mass. A heating rate holding circuit coupled to the differentiator receives a heating portion of the differentiated signal indicating a raising of the temperature of the thermal mass. A display meter coupled to the holding circuits adds the cooling and heating portions of the differentiated signal together, translates the differentiated signal into a power reading, and displays the power reading to a operator.

Pocket size laser power meter

A laser power meter and associated method are disclosed. The laser power meter has an absorber that is placed in a path of a laser beam during a power measurement, a temperature sensor for measuring the temperature of the absorber, a differentiator for determining a rate of change of the temperature of the absorber, and a processor that computes an estimated power of the laser beam based on the temperature and its rate of change without considering power related loss effects and then computes the power of the laser beam based on the estimated power and the temperature and its rate of change.

Laser power meter

Disclosed is a method for testing the performance of a heat pipe and an apparatus for conducting the performance test. The apparatus includes a heating device and a cooling device. Two ends of the heat pipe are thermally connected to the heating device and the cooling device, respectively. The heating device is applied to supply thermal energy to the heat pipe. When the quantity of thermal energy being transferred to the heat pipe reaches to a specified value, the temperatures at the two ends of the heat pipe are detected. If the temperature difference between the two ends is lower than a predetermined value, the heat pipe being tested is deemed as acceptable.

Method and apparatus for conducting performance test to heat pipe

A laser beam LB, which has entered a housing, travels via a reflection mirror and through a beam diffusion plate, ND filters 42 and a visible rays cut-off filter 44 to impinge on a beam receiving surface of a photodiode 46. A resistance heating element 48 in the form of, e.g., a metal film resistor and a power transistor 50 for the supply of electric power to the resistance heating element 48 are fixedly secured by bolts via respective insulating sheets with thermal conductivity to external wall surfaces of thick sidewalls 28d and 28e of a thermally conductive second retainer 28. The second retainer 28 is heated by both heat generated by the resistance heating element 48 and heat generated by the transistor 50. The second retainer 28 is provided also with a temperature sensor 52. A temperature control circuit accepts an output signal from the temperature sensor 52 and provides control of an output signal from the transistor 50 so as to allow the temperature of the second retainer 28 to conform to a set temperature.

Laser output measuring apparatus

An energy metering method and apparatus for liquid flow systems comprising first and second segments of one or more conduits through which a liquid flows, comprising: attaching a first temperature sensor for connection to an outside of the first conduit segment; attaching a second temperature sensor for connection to an outside of the second conduit segment; via a programmable control unit, receiving data from the sensors and calculating energy data therefrom; and communicating energy data from the meter; whereby the method and apparatus operate without need to temporarily disconnect or alter the first or second conduit segments The invention operates with both variable and fixed flow systems, and is especially useful for both active and passive solar energy systems

Non-invasive energy meter for fixed and variable flow systems

A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

James V. Micali

Papers

Radiation beam calorimetric power measurement system