Fill-level measuring device

Patent metadata

Field	Value
Publication number	US-9829367-B2
Application number	US-201314391187-A
Country	US
Kind code	B2
Filing date	Mar 19, 2013
Priority date	Apr 12, 2012
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A fill-level measuring device having an oscillatory system, which has at least one external, tubular, oscillatory element and an inner oscillatory element. The outer oscillatory element at least sectionally coaxially surrounds the inner oscillatory element. In an inner space of the inner oscillatory element, a compensation apparatus shiftable in the axial direction and having at least a first locking element, a second locking element and a coupling element is arranged. The locking elements and the coupling element are composed of piezoelectric material, wherein the coupling element, the first locking element and the second locking element are connected with one another, and wherein the first locking element and the second locking element in a resting state are each connected by force interlocking, e.g. friction interlocking, with a wall of the inner space, and the fill-level measuring device has an electronics unit, which is embodied to position the compensation apparatus at a predeterminable position by means of electrical signals.

First claim

The invention claimed is:

1. A fill-level measuring device comprising:
an oscillatory system, which is excitable to execute mechanical oscillations; and
an electronics unit,
wherein, said oscillatory system comprises;
at least one external, tubular, oscillatory element;
an inner oscillatory element; and
a compensation apparatus, wherein:
said external oscillatory element at least sectionally coaxially surrounds the inner oscillatory element;
said compensation apparatus is arranged in an inner space of said inner oscillatory element;
said compensation apparatus shiftable in the axial direction and has at least a first locking element, a second locking element and a coupling element;
said locking elements and said coupling element are composed of piezoelectric material;
said coupling element, said first locking element and said second locking element are connected with one another;
said first locking element and said second locking element, in a resting state, are each connected by force interlocking, e.g. frictional interlocking, with a wall of the inner space; and
said electronics unit is embodied to position said compensation apparatus at a predeterminable position by means of electrical signals.

2. The fill-level measuring device as claimed in claim 1 , wherein:
an added mass is secured to said first locking element and/or said second locking element.

3. The fill-level measuring device as claimed in claim 1 , wherein:
said inner oscillatory element is at least sectionally tubular.

4. The fill-level measuring device as claimed in claim 1 , wherein:
said compensation apparatus is embodied to move itself in the axial direction according to the inchworm principle.

5. The fill-level measuring device as claimed in claim 1 , wherein:
said locking elements are polarized in the radial direction; and
said coupling element is polarized in the axial direction.

6. The fill-level measuring device as claimed in claim 1 , wherein:
said coupling element is embodied in such a manner that said coupling element in the case of being supplied with an electrical voltage experiences a longitudinal extension in the axial direction.

7. The fill-level measuring device as claimed in claim 1 , wherein:
said electronics unit supplies said first locking element and said second locking element in the resting state with an electrical voltage; and for releasing the force interlocked connection between the wall and said first locking element or said second locking element, said electronics unit reduces the electrical voltage, which said first locking element or said second locking element is supplied in the resting state.

8. The fill-level measuring device as claimed in claim 1 , further comprising:
a driving/receiving unit, which excites said outer oscillatory element and the said inner oscillatory element to execute opposite mechanical oscillations with the resonant frequency of said oscillatory system.

9. The fill-level measuring device as claimed in claim 1 , wherein:
said electronics unit is embodied to shift said compensation apparatus upon a change of the frequency of the oscillations of said oscillatory system.

10. The fill-level measuring device as claimed in claim 1 , wherein:
said electronics unit is embodied to position said compensation apparatus in such a manner that the amplitude of the oscillations of said inner oscillatory element is maximum.

Assignees

• Endress Hauser Gmbh Co Kg

Inventors

• Pfeiffer Helmut
• Mack Benjamin

Classifications

• G01F23/2967 Primary

  for discrete levels · CPC title

• G01F23/296 Primary

  Acoustic waves · CPC title