Abstract: A device for photoelectrically starting and stopping the operation of a bunsen burner in response to the shadow of an operator's hand holding an object to be heated includes a solenoid valve in a line supplying gas to the burner and electronic control circuitry having secondary and primary photoelectric cells arranged in a differential response circuit. Changes in the intensity of the ambient light are cancelled by the differential response circuit, while a hand shadow, which affects only the primary cell, triggers the solenoid valve, via a gate circuit and solenoid switch.

Abstract: A steam generating apparatus which includes a novel gas burner and consisting of a pair of spaced coaxial cylinders, the outer of which is of considerably greater axial length than the inner and both of which are provided with apertures for admixing the gas with air. The inner cylinder functions as an integral pilot burner which is highly stable. The steam generating apparatus heats water to provide steam, heats it still further, then condenses the steam into liquid to assist in the formation of still more steam.

Abstract: A device for electrically starting and stopping the operation of a gas burner in response to the shadow of the user's hand holding an object to be heated, the device including a solenoid valve in the gas line and a dimmer circuit with a directional photoelectric sensor, a switching amplifier, and a valve relay controlling the solenoid valve. The dimmer circuit can be bypassed for continuous operation by means of a selector switch.

Abstract: Gas burner which is constructed of a connecting part in which the gas is mixed with primary air and of an outflow part of sheet material, with a number of annularly arranged and radially directed slits folded into a star-shaped configuration in which the height H of the star-shaped folds is a multiple of the radial dimension R of these folds, while the cross sectional area of each slit is larger near the circumference of the ring than in the center.