Bindicator Company

Berwind Corporation

Randall J Regentin

John T Knepler

Norman F Marsh

Phillip P Fleckenstein

A system for measuring level of liquid material in a containment vessel that includes a hollow conduit composed of a first conduit section having an upper end coupled to a pressure sensor and a lower end disposed within the vessel. A second conduit section is coupled to the lower end of the first conduit section and extends downwardly therefrom at least to a minimum material measurement level within the vessel. The second conduit section has a vertical height coordinated with the maximum desired material measurement level within the vessel such that pressure of air captured within the first conduit section at such maximum material level prevents entry of the liquid material into the first conduit section. The cross sectional area of air flow within the second conduit section is at least ten times, and preferably at least sixteen times, greater than the cross sectional area to air flow within the first conduit section. Thus, the volume of air captured within the air column formed by the first and second conduit sections is minimized, thereby minimizing the effects of temperature-induced fluctuations of column air pressure. On the other hand, liquid level within the air column remains at all times within the conduit section of larger diameter, thereby reducing the likelihood of clogging of the small-diameter conduit section due to sediments or the like carried by the liquid.

Liquid level measurement system

Apparatus for indicating level of material comprises a cable vertically suspended so as to contact and be surrounded by the material. The cable is suspended from a cam follower mechanism that engages a cam coupled to a motor for selectively introducing slack in the cable, such that the upper portion of the cable unsupported by the material engages and is suspended from a load cell. Circuitry is responsive to cable weight measured by the load cell for indicating level of the material. The motor comprises a rotary electric motor having a horizontal axis of rotation perpendicular to the vertical cable. The cam comprises a cam plate coupled to the motor to rotate about the motor axis and having an asymmetric periphery surrounding the axis of rotation. The cam follower mechanism comprises an arm pivotally mounted in fixed position adjacent to the cam plate and supporting a roller that engages the cam plate periphery. The cable is suspended from the pivot-remote end of the arm, so that weight of the cable and the roller arm hold the roller in contact with the cam plate periphery. The level-indicating circuitry is microprocessor-based and includes facility for indicating level over a 4-20 ma current range, with automatic output correction for changeds in circuit characters.

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Deckerville, MI, United States of America

Randall J Regentin