US 4,804,944 A · Hall effect liquid level sensing apparatus and method

Abstract

Disclosed herein is a Hall-effect liquid level sensing apparatus and method. The device may be mounted on a liquid storage tank and includes at least one float suspended within the tank and floating upon a hollow tube for guidance. The float carries a permanent magnet and a Hall-effect sensor may be reciprocated within the hollow tube to sense the location of the permanent magnet and thereby the location of the float. The device further includes a control device including an optical encoder which enables the device to sense the depth in the hollow tube to which the Hall-effect device has travelled when it senses the height of the permanent magnet. The invention may be used in conjunction with a plurality of floats to determine not only the liquid level but also the level between the liquid and a diverse liquid contained within the same container. In this embodiment, the invention may also be used in conjunction with a specific gravity measuring device so as to ensure that the pressure sensing orifice of the specific gravity measuring device is suspended within the liquid the specific gravity of which is desired to be measured.

Claims21

Dependent claims

An improved level sensing device for mounting in an enclosure, said enclosure having fluid therein, the level of which is to be monitored, said device comprising:

(a) an elongated tube mounted vertically in said enclosur and having a passageway therethrough;
(b) at least one float slidably guided by said tube and having a magnet mounted thereon;
(c) an accumulator mounted on said enclosure and having said tube mounted thereon, said accumulator having an opening in communication with said passageway;
(d) an elongated tape stored in said accumulator and adapted to be reciprocated through said opening and within said tube;
(e) said tape having a first end electrically connected to control means for controlling said device and a second end having connected thereto magnetic sensing means for sensing the magnetic field emanating from said magnet;
and
(f) tape sensing means for sensing the vertical position of said magnetic sensing means and communicating first signals indicative of said vertical position to said control means, said control means receiving second signals from said magnetic sensing means indicative of the vertical position of said float and calculating from said first and second signals the level of fluid in said enclosure.

4 more elements

Dependencies are inferred from the claim text.

Hall effect liquid level sensing apparatus and method

Life of this patent

Hall effect liquid level sensing apparatus and method

Life of this patent

Abstract

Claims21