Apparatus for indicating the characteristics of a fluid is disclosed in accordance with the teachings of the present invention wherein the fluid is permitted to pass freely within a chamber which contains a float disposed for limited vertical movement and minimal lateral deflection. Vertical movement of the float is communicated to an electrically conductive member mechanically coupled thereto. The electrically conductive member is in close proximity and magnetically coupled to a magnetization inductance coil, causing variations in the inductive properties thereof thereby affecting the magnetic field generated by energization of the coil. Inductance of the coil or generated magnetic field is measured by remote measuring devices whereby the fluid characteristics are indicated. Alternatively, the electrically conductive material may be disposed in an electric field produced by a conducting plate, thereby effecting with said conducting plate, a variable capacitance means. This invention relates to an apparatus for measuring the density or displacement characteristics of a fluid to provide indications of such characteristics remote from the measuring element, and more particularly, to a proximity type measuring device. In order to ascertain particular characteristics, such as the liquid density or the liquid level of a fluid body in processing equipment, it is common to provide optical measuring devices in the form of liquid level gauges wherein the liquid level or fluid density of the liquid may be determined by visual observation at a point adjacent such processing equipment. In the large processing apparatus presently used in industry, in many instances, it is impossible to make direct visual observations of the liquid level or other characteristics of the liquid at the various points in the processing equipment. Even if such points are accessible to the operators, it is much more desirable to have multiple indications of the various characteristics of the fluid passing through the processing equipment conveniently shown at one central point which is usually remote from the processing equipment itself. In order to provide for remote indication of fluid characteristics, there have been developed various instruments including electrical means for remote signaling of the instantaneous fluid characteristics at one or more stations along the processing equipment. A conventional method for determining the specific gravity of a liquid or the liquid level of said liquid within processing apparatus is to employ a float of predetermined mass and volume which is wholly or partially submerged in the liquid whose characteristics are to be determined. The resulting force of displacement by the liquid on the float is therefore a measurement of the liquid level or specific gravity of the liquid displacing the float, and various electrical means have been provided for indicating the displacement force on the float at a point some distance from the float itself. Therefore, it is an object of this invention to provide an improved apparatus for measuring float displacement characteristics of a fluid in which the measuring element or transducer and the displacement element may be both mounted directly in the vessel or chamber forming a portion of the process equipment thereby totally eliminating errors in measurement due to the normal remote location of the measuring element from the chamber containing the float. It is a further object of this invention to provide an improved apparatus for measuring the displacement characteristics of a fluid in which the float is directly coupled to an electrical transducer in the form of a proximity sensing device employing magnetic coupling. It is a further object of this invention to provide an improved apparatus of this type in which the extremely small motion of the fluid displacement element needed to effect the desired output signal permits guiding of the float with a minimum effect on accuracy. It is a further object of this invention to provide an improved apparatus of this type in which the proximity sensing device may be easily protected from the atmosphere of the chamber carrying the fluid whose characteristics are to be measured. It is a further object of the invention to provide a measuring system of the proximity sensing type suitable for remote electrical indication which consumes extremely small amounts of power, operates for long periods of time, is intrinsically safe electrically, may be operated in hazardous areas, and requires minimum maintenance. Various other objects and advantages of the invention will become clear from the following detailed description of embodiments thereof, and the novel features will be particularly pointed out in connection with the appended claims. In accordance with this invention, apparatus for remotely indicating the characteristics of a fluid is provided wherein a float is positioned within a fluid vessel, said float being disposed for one dimensional movement and having a rigid shaft mechanically coupled thereto; said shaft has an electrically conductive member mounted therealong which is magnetically coupled to a source of magnetic field; the inductive properties of the source vary as the distance between the source and electrically conductive member varies; the inductive properties are measured at a remote location and indications thereof are representative of the characteristics of the fluid. A source of electric field may be substituted for said source of magnetic field to obtain a variable capacitive means, the capacitance of which is representative of the characteristics of the fluid.
A high temperature pressure transducer for measuring the total pressure adjacent the exit orifice of a crucible containing molten metal used in a continuous casting operation is disclosed. The pressure sensed includes a pressure head of the molten metal as well as the gas gauge pressure in the crucible above the metal. The transducer includes a sensor rod assembly having an immersible sensor rod fabricated of fused quartz and having a sensing surface, a sensor rod extension, an intermediate shaft, and a load cell connected to the intermediate shaft. A bellows provides a gas tight seal for the internal gas pressure in the crucible. The bellows is characterized by folds projecting inwardly and outwardly and providing equal volume in the two directions. By having a constant volume, it follows that the surface area of the folds in the two directions is the same so that any pressure changes along the bellows cancels out and does not adversely affect the reading at the load cell thereby assuring an accurate total pressure reading. In addition, a process is disclosed for controlling the flow rate of molten metal from the exit orifice of a closed crucible wherein the total gas and liquid pressure measurement obtained by the high temperature pressure transducer is used as an input into a control circuit which controls the amount of pressurized gas or vacuum applied to the crucible.
An autonomous apparatus for measuring the amount in volume, weight or level of a liquid in a tank. The invention provides an easy to read digital numerical display in what ever units the user has calibrated it for, indicating the amount of fluid in the tank. The self-contained electronic devise is normally mounted to a pipe nipple on the top of an above ground storage tank. An attached displacement device extends down through the pipe nipple into the liquid to sense the level of the liquid. This device relies on ambient light to power the solar cells and recharge a battery, which provides all the necessary power to operate the device both day and night. The apparatus is designed to be intrinsically safe and totally sealed. As such it operates electrically as a stand alone gauge and is intended as a general purpose indicator of tank contents for any tank location.
Apparatus for detecting the level of a liquid. A metal-detecting proximity sensor is placed near a non-metallic, vertically-positioned guide shaft. A float is placed on the liquid. A tube has one end attached to the float and the other end insertably placed within the guide shaft. A piece of metal is placed within the tube. When the apparatus is used for determining when the level of the liquid reaches a predetermined value, the metal piece has a boundary which is located at the height of the proximity sensor only when the liquid level is at its predetermined value. When the apparatus is used for measuring the level of the liquid, the proximity sensor has an output signal proportional to the distance from itself to metal and the metal piece has an outer surface whose distance to the proximity sensor at the height of the proximity sensor, changes with changes in the liquid level.
