Clark-reliance Corporation

Mark A Colman

David E Brown

Michael J Kett

Thomas H Lee

Thomas Eliott Lee

An improved boiler water-level controller. According to one aspect of the present invention, a positive blowdown signal is presented to indicate to the operator that the alarm probe is in steam; performing blowdown until this indicator turns on helps ensure that the alarm probe is working properly. According to another aspect of the present invention, the controller uses a novel methodology of sensing water level using conductivity probes. An embodiment of this methodology uses the charging and discharging of a capacitor through a resistive value to sense the presence of water.

Automatic boiler level controller

The present invention provides a method and system for detecting and cross-checking faulty sensors in liquid level indicators and controllers. A liquid level indicator and controller in which one embodiment of the present invention operates includes a control unit for controlling the other components of the liquid level indicator and controller, sensors electrically connected to the control unit for sensing the level of a liquid in a vessel, and an indicating device electrically connected to the control unit for displaying the liquid level. The control unit includes a monitor and a fault detector. In operation, the liquid level indicator and controller has two (2) basic modes. The first mode is a monitor mode. In this mode, the liquid level indicator and controller, under the control of the monitor, senses the liquid level in the vessel using the sensors and displays the liquid level on the indicating device. The second mode is a fault detection mode. In this mode, the liquid level indicator and controller, under the control of the fault detector, detects and cross-checks faulty sensors. If a faulty sensor is detected, the liquid level indicator and controller determines the type of fault, i.e., whether the sensor is open or shorted.

Method and system for detecting and cross-checking faulty sensors in liquid level indicators and controllers

Lighting assemblies are provided for visual indicators which indicate the level of fluid in a container. One such assembly comprises a backlighting assembly for a visual fluid level indicator having front and rear transparent viewing windows for viewing the level of a fluid contained therein, comprising (i) a substantially flat fiber optic panel located proximate the rear transparent viewing window; (ii) an attachment mechanism for attaching the substantially flat fiber optic panel to the visual fluid indicator proximate the rear transparent viewing window; and (iii) an illumination source optically coupled to the substantially flat fiber optic panel. The illumination source is a gas filled light source operating at less than 25 volts A.C. which is enclosed in a waterproof and explosion-proof enclosure, and which is optically coupled to the fiber optic panel by a fiber optic light cable. The lighting assembly may also be used for directly illuminating a magnetic fluid level indicator which indicates the level of fluid in a container to which it is attached.

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Duluth, GA, United States of America

Mark A Colman