Consistometer with internal calibration means

Claim 1

A consistometer for continuous measuring the consistency of a stream of material from apparatus manufacturing the material comprising a rotatable resilient member located in said stream so that the opposite surface about which said member is flexible is substantially parallel to the direction of flow in said stream, means for rotating said member at a constant rotate about an axis which is parallel to the direction of flow in said stream, a reference member, means for rotating the reference member in synchronism with the resilient member, resilient member sensing means spatially related to the resilient member for providing a resilient member signal in accordance with the movement of the resilient member, reference member sensing means spatially related to the reference member for providing a reference member signal in accordance with the movement of the reference member, noise means connected to both sensing means for providing an enabling pulse in accordance with the reference member signal and the resilient member signal, first comparison means connected to the reference member sensing means and to the noise means for comparing the reference member signal with a predetermined voltage, corresponding to an acceptable reference member signal level, when enabled by an enabling pulse, and providing a first comparison signal at one level when the reference member signal is an acceptable signal and at another level when it is not acceptable and for not making the comparison when the noise means does not provide an enabling pulse when not making the comprison; reference member pulse means connected to the first comparison means for providing a reference member pulse in response to the first comparison signal going from the other level to the one level; resilient member pulse means connected to the resilient member sensing means for providing a resilient member pulse in accordance with the resilient member signal; a flip-flop connected to both pulse means provides a signal corresponding to the consistency of the material, in accordance with the resilient member, member pulses and the reference member pulses; output means connected to the flip-flop for providing an output corresponding to the consistency of the material in accordance with the signal from the flip-flop; and calibration means connected to the flip-flop, the resilient member pulse means and to the resilient member pulse means for providing calibration pulses of a predetermined repetition rate to the flip-flop while blocking the resilient member pulses and the reference member pulses so that output means may be calibrated.