Vibration method and apparatus for measuring the level of material in a container

Claim 3

The method according to claim 1, wherein the rope is continuously excited and wherein the response is continuously sensed.

Claim 6

The method according to claim 1, wherein the rope is placed within a variable electromagnetic field, causing the exciting frequency of the magnetic field to coincide with the resonance frequency of the rope and measuring the exciting frequency.

Claim 7

The method according to claim 4 wherein the variable electromagnetic field is provided with an exciting frequency range matched to the maximum range of frequency change of the free rope portion.

Claim 8

The method according to claim 5, including the step of measuring the resonance frequency of the free rope portion by determined the time intervals between the null nodes of the exciting frequency.

Claim 9

The method according to claim 1 including the step of arranging the sensing point offset from the exterior tensioning point and exciting the free rope portion so as to provide a succession of generated waves and waves reflected from the surface of the material in the container, sensing each wave and determining the time elapsed between a number of them, said elapsed time being indicative of the distance between the sensing point and the variable level of material.

Claim 10

The method according to claim 7, including the steps of obtaining an electrical control signal derived from successive generated and reflected waves passing the sensing point, the elapsed time between signals derived from the successive generated and reflected waves being proportionately to twice the distance from the sensing point to the variable level of the material.

Claim 11

The method according to claim 8, including the step of defining the time interval between successive signals in minute units whereby small distances may be indicated.

Claim 12

The method according to claim 1 including the step of arranging the sensing point offset from the exterior tensioning point and exciting the free rope portion so as to provide generated waves and waves reflected from the surface of the material in the container, sensing the amplitude of a generated wave and of a reflected wave, comparing said sensed amplitudes and corresponding to the dampening constant of said rope determining the distance between the sensing point and the variable level of material in the container.

Claim 13

The method according to claim 10, including the step of passing successive generated and reflected waves past the sensing point and deriving a control signal corresponding to each relative to the amplitude of the waves, the difference in amplitude between said successive signals being proportional to twice the distance from the sensing point to the variable level of the material.

Claim 14

The method according to claim 11 including the step of defining the ratio between amplitudes in minute units whereby small distances may be indicated.

Claim 15

The method according to claim 1 including the steps of indicating the response digitally.

Claim 16

The method according to claim 1 including the Step of indicating the responses as an analog.

Claim 17

The method according to claim 1 wherein a plurality of sensing points each associated with a container have their outputs successively fed through a timed multiplex system to individual indicator wherein the values are correspondingly displayed.

Claim 18

The method according to claim 15, wherein said indicators include storage means for retaining successive values.

Claim 19

The method according to claim 16 including the step of synchronizing the periodic obtaining of the sensed value with a periodically functioning stepping switch.

Claim 20

The method according to claim 17, including the step of tuning the output time of each sensing point to the measuring duraction of the corresponding maximum free rope portion.

Claim 21

The method according to claim 18 wherein the duration of the exciting period is selected greater than the given output time of the maximum free rope portion.

Claim 22

The method according to claim 19 including the step or arranging the rope so that the portion thereof exterior of the container is held fast whereby the length between the full condition of the container itself.

Claim 23

Apparatus for measuring the level of material in a container comprising a single rope, means for anchoring one end of said rope in the bottom wall of said container, and means for fastening the other end of said rope exterior of said container above the top thereof, means for maintaining said rope under constant tension, said rope passing through the material located in said container, said material surrounding a portion of said rope and leaving a portion thereof between the surface of the material and the exterior fastening means free, means for exciting the free rope portion between the exterior fastening point and the level of said material to vibrate transversely of its length, sensing means positioned adjacent said free rope portion for sensing the vibrations generated by rope in response to said excitement means and means for determining the level of material in said container as a function of the relative variations of this response in selected ones of resonance frequency, wave length and amplitude of said vibrations with respect to at least one of the distances between said sensing means and the level of said material, the level of said material and the anchoring point within said container and the level of said material and the exterior fastening point.

Claim 24

Apparatus for measuring the level of material in a container comprising a single rope, means for anchoring one end of said rope in the bottom wall of said container, and means for fastening the other end of said rope exterior of said container above the top thereof, means for maintaining said rope under constant tension, said rope passing through the material located in said container, said material surrounding a portion of said rope and leaving a portion thereof between the surface of the material and the exterior fastening means free, means for exciting the free rope portion between the exterior fastening point and the level of said material to vibrate transversely of its length, sensing means positioned adjacent said free rope portion for sensing the vibrations generated by rope in response to said excitement means and means for determining the level of material in said container as a function of the relative variations of this response in selected ones of resonance frequency, wave length and amplitude of said vibrations with respect to at least one of the distances between said sensing means and the level of said material, the level of said material and the anchoring point within said container and the level of said material and the exterior fastening point.

Claim 25

The apparatus according to claim 21, including means for periodically exciting the free rope portion and means for controlling the sensing and determination of the response in periodic intervals corresponding thereto.

Claim 26

The apparatus according to claim 21, wherein a portion of said rope is provided with ferromagnetic means and is set with a variable electromagnetic field, said electromagnetic means including means for causing the field frequency to correspond to the resonance frequency of the excited rope and means for determining the field frequency.

Claim 27

The apparatus according to claim 21 wherein the means for exciting the rope comprises a hammer adapted to strike the rope transversely of its direction of tensioning.

Claim 28

The apparatus according to claim 21 wherein the sensing means comprises an inductive transducer providing an electrically controlled impulse of constant amplitude and the determining means comprises a timing generator and stepping register controlled thereby.

Claim 29

The apparatus according to claim 21 including means for indicating the determined relative variations in level.

Claim 30

The apparatus according to claim 21 including means responsive to the determined relative variations for controlling the filling or emptying of said container.