US 5,307,678 A · Material level probe having crimp seal

Abstract

A level measuring probe in which all potential leakage paths are closed by concentrically shrinking the outmost diametrical surface of the probe by some mechanical means such as a crimper or rotary swager to provide sufficient force to substantially uniformly deform the ground, guard, and active elements and insulators around the circumference of the probe such that multiple seals are created. A circumferential notch is preferably provided in the active probe element at the point of the crimping or swaging to provide "blowout protection" whereby the active probe electrode is held in place when used in a high pressure vessel. A pressure seal between the electrodes and insulation material is also maintained by using an elastomeric insulator which returns to its original shape after heating or a thin electrode which "gives" a little when the insulator expands radially during heating. The arrangement of the invention thus eliminates the need for costly machined parts and bushings to provide pressure seals.

Claims30

Dependent claims

A probe for measuring the level of a material in a container, comprising:

a rod-shaped probe element having a central axis;
a tubular ground element coaxially surrounding and radially spaced from said probe element but having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said ground element;
an insulating layer completely surrounding said probe element between said ground element and said probe element to insulate said ground element from said probe element;
a seal formed along said central axis of said probe element by substantially uniformly deforming said ground element and said insulating layer in a radially inward direction towards said probe element until all leakage paths among said probe element, said ground element and said insulating layer are substantially eliminated;
and
means for mounting said probe within said container for measurement of the level of said material.

3 more elements

A probe for measuring the level of a material in a container, comprising:

a rod-shaped probe element having a central axis;
a tubular guard element coaxially surrounding and radially spaced from said probe element but having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said guard element;
a first insulating layer completely surrounding said probe element between said guard element and said probe element to insulate said guard element from said probe element;
a tubular ground element coaxially surrounding and radially spaced from said guard element but having a length along said central axis which is shorter than a length of said guard element along said central axis whereby said guard element projects from one end of said ground element;
a second insulating layer completely surrounding said guard element between said ground element and said guard element to insulate said ground element from said guard element;
a seal formed along said central axis of said probe element by substantially uniformly deforming said guard element, said ground element and said first and second insulating layers in a radially inward direction towards said probe element until all leakage paths among said probe element, said guard element, said ground element and said first and second insulating layers are substantially eliminated;
and
means for mounting said probe within said container for measurement of the level of said material.

5 more elements

A method of manufacturing a probe for measuring the level of a material in a container, comprising the steps of:

providing a rod-shaped probe element having a central axis;
inserting said probe element into a tubular insulating layer which coaxially surrounds and is radially spaced from said probe element after insertion of said probe element, said insulating layer completely surrounding said probe element;
inserting said probe element and said insulating layer into a tubular ground element which coaxially surrounds and is radially spaced from said insulating layer after insertion of said probe and said insulating layer, said ground element having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said ground element and is separated from said ground element by said insulating layer;
forming a seal along said central axis of said probe element by substantially uniformly deforming said ground element and said insulating layer in a radially inward direction towards said probe element until all leakage paths among said probe element, said ground element and said insulating layer are substantially eliminated;
and
mounting a resulting assembly within said container for measurement of the level of said material.

3 more elements

A method of manufacturing a probe for measuring the level of a material in a container, comprising the steps of:

providing a rod-shaped probe element having a central axis;
placing a tubular ground element so as to coaxially surround and be radially spaced from said probe element, said ground element having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said ground element after placement;
injection molding insulation material in a one-piece unitary construction surrounding said probe element between said probe element and said ground element such that said insulation material completely insulates said probe element from said ground element;
forming a seal along said central axis of said probe element by substantially uniformly deforming said ground element and said insulation material in a radially inward direction towards said probe element until all leakage paths among said probe element, said ground element and said insulation material are substantially eliminated;
and
mounting a resulting assembly within said container for measurement of the level of said material.

3 more elements

A method of manufacturing a probe for measuring the level of a material in a container, comprising the steps of:

providing a rod-shaped probe element having a central axis;
inserting said probe element into a first tubular insulating layer which coaxially surrounds and is radially spaced from said probe element after insertion of said probe element, said first insulating layer completely surrounding said probe element;
inserting said probe element and said first insulating layer into a tubular guard element which coaxially surrounds and is radially spaced from said first insulating layer after insertion of said probe and said first insulating layer, said guard element having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said guard element and is separated from said guard element by said first insulating layer;
inserting said probe element, said first insulating layer and said guard element into a second tubular insulating layer which coaxially surrounds and is radially spaced from said guard element after insertion of said guard element, said second insulating layer completely surrounding said guard element;
inserting said probe element, said first insulating layer, said guard element and said second insulating layer into a tubular ground element which coaxially surrounds and is radially spaced from said guard element, said ground element having a length along said central axis which is shorter than a length of said guard element along said central axis whereby said guard element projects from one end of said ground element;
forming a seal along said central axis of said probe element by substantially uniformly deforming said ground element, said guard element and said first and second insulating layers in a radially inward direction towards said probe element until all leakage paths among said probe element, said ground element, said guard element and said first and second insulating layers are substantially eliminated;
and
mounting a resulting assembly within said container for measurement of the level of said material.

5 more elements

A method of manufacturing a probe for measuring the level of a material in a container, comprising the steps of:

providing a rod-shaped probe element having a central axis;
placing a tubular guard element so as to coaxially surround and be radially spaced from said probe element, said guard element having a length along said central axis which is shorter than a length of said probe element along said central axis whereby said probe element projects from one end of said guard element after placement;
placing a tubular ground element so as to coaxially surround and be radially spaced from said guard element, said ground element having a length along said central axis which is shorter than a length of said guard element along said central axis whereby said guard element projects from one end of said ground element after placement;
injection molding insulation material in a one-piece unitary construction surrounding said probe element between said probe element and said guard element and surrounding said guard element between said guard element and said ground element such that said insulation material completely insulates said probe element from said guard element and said guard element from said ground element;
forming a seal along said central axis of said probe element by substantially uniformly deforming said ground element, said guard element and said insulation material in a radially inward direction towards said probe element until all leakage paths among said probe element, said ground element, said guard element, and said insulation material are substantially eliminated;
and
mounting a resulting assembly within said container for measurement of the level of said material.

4 more elements

Dependencies are inferred from the claim text.

Material level probe having crimp seal

Life of this patent

Material level probe having crimp seal

Life of this patent

Abstract

Claims30