US 4,374,475 A · Differential pressure gauge

Abstract

A differential pressure gauge of the type comprising a controlling magnetic helix device carrying a pressure indicating pointer, the position of which is controlled by a magnet magnetically coupled to same and mounted on the free end of a helically coiled bourdon tube exposed to differential pressures within the gauge and anchored in the gauge housing at its other end for this purpose. The magnet has a planar pole face paralleling the axis of the helix and defines a magnetic axis that is normal to and intersects the helix axis. The gauge housing defines an integral one piece pressure wall that separates and physically seals the helix from the magnet and bourdon tube and defines within the gauge housing pressure cavity an operating space within which the magnet and its supporting bourdon tube are mounted and operate. Between the helix and the magnet the pressure wall is of film dimensions to allow close placement of the magnet and helix relative to each other, and for defining a magnetic flux passing "window"; the pressure wall is contoured to stress in bending. The bourdon tube is mounted on a mounting plate or crossmember disposed within the pressure cavity, and the mounting plate is arranged for calibrating the gauge by adjustment of the mounting plate, the bourdon tube it carries, and the magnet, as a unit, toward and away from the helix. The gauge includes a zero datum and a device for setting the indicating pointer on the zero datum from exteriorly of the gauge, including an adjustment mechanism coupled to the helix and seated on the housing in alignment with the helix axis.

Claims20

Dependent claims

In a gauge that includes linear to rotary motion transforming means including a helix journalled for rotation about its longitudinal axis, and a magnet for producing rotational movement of said helix about its said axis in response to movement of the magnet alongside and lengthwise of said helix axis,

the improvement including:
a bourdon tube spaced from said helix,
one end of said tube being sealed and mounting a support arm on which the magnet is mounted,
means for mounting said tube at the other end of same,
with the other end of said tube being sealed and including means for connecting said tube other end to a fluid pressure source,
said mounting means including means for adjusting said tube toward and away from said helix axis.

3 more elements

In a gauge that includes linear to rotary motion transforming means including a helix journaled for rotation about its longitudinal axis, with the helix having an indicator connected thereto, a magnet for producing rotational movement of said helix about its said axis in response to linear movement of the magnet alongside and lengthwise of said helix axis, and a housing for the helix and magnet, with the magnet liner movement path and the helix axis being in coplanar relation,

the improvement including:
a bourdon tube helically coiled about a rectilinear axis and disposed in said housing spaced from said helix with said magnet disposed between the helix and said tube and said tube axis extending crosswise of said plane,
one end of said tube being sealed and mounting a support arm lying in said plane on which the magnet is mounted for movement in said plane,
means for mounting said tube in fixed relation to the housing at the other end of same,
with the other end of said tube being sealed and including means for connecting said tube other end to a fluid pressure source exterior of the housing,
said mounting tube means including means for adjusting said tube toward and away from said helix axis.

3 more elements

In a pressure gauge that includes linear to rotary motion transforming means including a helix journaled for rotation about its longitudinal axis, with the helix having an indicator connected thereto, a magnet for producing rotational movement of said helix about its said axis in response to linear movement of the magnet alongside and lengthwise of said helix axis, and a housing for the helix and magnet, a zero datum adjacent to which the indicator is disposed, with the housing defining a pressure chamber in which the magnet is mounted, and including sensing means mounted in said pressure chamber for shifting said magnet in a path extending lengthwise of said helix in response to differential pressure changes in said chamber, with the magnet path and the helix axis being in coplanar relation,

the improvement including:
a bourdon tube helically coiled about a rectilinear axis and disposed in said housing pressure chamber spaced from said helix with said magnet disposed between the helix and said tube and said tube axis extending crosswise of said plane of said magnet path and helix axis,
one end of said tube being sealed and mounting a support arm lying in said plane on which the magnet is mounted for movement in said plane,
means for mounting said tube in fixed relation to the housing at the other end of same,
with the other end of said tube being sealed and including means for connecting said tube other end to a first fluid pressure source exterior of the housing,
said tube comprising said sensing means,
and means for connecting the housing pressure chamber to a second fluid pressure source exterior of the housing,
said mounting means including means for adjusting said tube toward and away from said helix axis.

5 more elements

Dependencies are inferred from the claim text.

Differential pressure gauge

Life of this patent

Differential pressure gauge

Life of this patent

Abstract

Claims20