Abstract: A dual sided sheet surface property sensor has the capability to simultaneously measure both sides of a moving sheet at the same location of the sheet on the top and bottom surfaces of the sheet. The energy directed to each side of the sheet may include UV, visible light, infrared, radio frequency, microwave, broadband, or X-ray. The sensor has a source and associated detector on each side of the moving sheet and each source provides energy at a different modulation frequency and the associated detector is responsive only to that frequency.

Abstract: A dual sided sheet surface property sensor has the capability to simultaneously measure both sides of a moving sheet at the same location of the sheet on the top and bottom surfaces of the sheet. The energy directed to each side of the sheet may include UV, visible light, infrared, radio frequency, microwave, broadband, or X-ray. The sensor has a source and associated detector on each side of the moving sheet and each source provides energy at a different modulation frequency and the associated detector is responsive only to that frequency.

Abstract: A non-contact system for sensing a property of a passing web of material includes first and second sensors positioned on opposite sides of the web. The opposing sensors are repelled from the web and each other by gas bearings formed between the sensors and the web and attracted to each other by one or more polarized magnets embedded in the sensors. The resultant net force properly spaces the sensors from the web to ensure reliable and accurate sensing. The repelling force enables the sensors to react substantially instantaneously to changes in the pass line of the web. An automatic actuator/retractor can be provided to withdraw the sensors, extend the sensors to or retract the sensors from adjacent the feed path.

Abstract: A non-contact system for sensing a property of a passing web of material includes first and second sensors positioned on opposite sides of the web. The opposing sensors are repelled from the web and each other by gas bearings formed between the sensors and the web and attracted to each other by one or more polarized magnets embedded in the sensors. The resultant net force properly spaces the sensors from the web to ensure reliable and accurate sensing. The repelling force enables the sensors to react substantially instantaneously to changes in the pass line of the web. An automatic actuator/retractor can be provided to withdraw the sensors extend the sensors to or retract the sensors from adjacent the feed path.

Abstract: On-line measurement of fiber orientation and anisotropy in a non-woven web of material is performed by directing three light sources toward a sensing region of the web. Reflectively scattered light from each light source is detected by a pair of light sensors positioned on either side of an incidence plane including the beam of incident light. Back scattered light from each light source is also detected by at least one light sensor positioned generally above the sensing region. Preferably two back scattered light sensors are provided for each light source, one common light sensor and one dedicated light sensor. The signals from the light sensors for each of the light sources are combined to generate resultant fiber orientation signals which are used to compute a fiber orientation angle relative to the machine direction and an anisotropy characteristic for the web.