Abstract: The two dimensional processing path along which the electron beam of a welder is to be deflected during a processing cycle is approximated by a sequence of points separated by predetermined distances from one another. The deflection signals for the beam are derived from analog signals having levels corresponding to the points, and interpolation there between. The rate of interpolation depends on the distance between the points and time intervals specified so as to create preselected beam velocities. Since a weld is improved when there is micromotion of the beam around the processing, a modulation path generator is also provided. Since the coordinates furnished by this modulation path generator are in a fixed coordinate system and the micromotion of the beam is relative to the processing path, a coordinate rotation is carried out before the modulation signals are superimposed upon the processing path deflection signals.

Abstract: A welder utilizes a focussed electron beam which is deflected along the processing path required to weld two pieces together and is also oscillated about the processing path in accordance with a modulation curve. The modulation curve is approximated by a sequence of points. The coordinates of the points in a predetermined coordinate system are read out sequentially from a digital storage and converted to analog signals. The analog signals are subjected to low pass filtering and then applied to the deflection system for the electron beam. The cut-off frequency of the low pass filter is a predetermined multiple of the readout frequency of the digital data. When the velocity of the beam along the modulation curve changes, the cut-off frequency and the readout frequency are adjusted simultaneously. Additionally, the position of the focus and/or the intensity of the electron beam can be varied as the beam traces out the modulation curve.

Abstract: Heat of liquefaction and solidification is transmitted between a heat storing material undergoing the phase transition and a heating medium in a heat exchanger by means of a partly gaseous, partly liquid fluid sealed in a heat pipe a portion of which is received in the container for the aforementioned material, and which is equipped with fins in direct contact with the heat storing material while a second portion of the heat pipe is in thermal contact with the heating medium in the heat exchanger.