Abstract: A felt conditioning system is disclosed for use in connection with paper-making apparatus wherein an endless belt of absorbent felt is pressed at a station along the path of belt motion, into contact with a paper sheet in order to de-water the latter. In accordance with the invention, the felt is purged of water and other foeign matter transferred thereto from the paper, by passing the belt around a hollow, foraminous conditioning roll at high speed. Air pressure controlled within selected limits is applied to a portion of the inside surface of the belt in contact with the roll. The combined action of centrifugal force, air pressure and gravity expels the water and foreign matter carried by the belt.

Abstract: A sensing device is used to measure absolute humidity of a sample stream of gas by measuring the mass flow rate of the sample, adding or subtracting a known amount of heat energy (per unit mass of the sample stream) to the heat energy of the sample and measuring the temperature of the sample before and after the heat energy of the sample is changed. These measured parameters are then used to calculate the specific heat of the sample, which in turn can be used to calculate the water vapor content of the gas.

Abstract: Inherent defects in the angular relationship between facets of a rotating polygonal mirror used to sequentially scan a beam of radiation are corrected by an optical reflecting or refracting element pivotally mounted in the path of the radiation. With the use of electromechanical devices energized by timed electrical signals of appropriate value, the mirror or refracting element is pivoted to correct the scanning errors caused by angular defects in the rotating mirror. The effect of variations in the angles between facets of the polygonal mirror are also corrected by an electronic circuit which includes a delay device capable of delaying the scanning by a predetermined amount. Control means for the electromechanical devices and for the delay device are pre-programmed so as to make the proper adjustments for each facet of the rotating polygonal mirror.