US1006100A - Differential-pressure gage. - Google Patents

Description

W. G. KENT & J. L. HODGSON.

DIFFERENTIAL PRESSURE GAGE APPLICATION FILED APR.25,1910.

Patented Oct. 17,1911.

WWII/E8358 INVENTORS Walter G Kent fiaflyzlmi JIM i John LHodgson UNITED STATES PATENT OFFICE.

WALTER GEORGE KENT AND JOHN LAWRENCE HODGSON, OF LONDON, ENGLAND.

DIFFERENTIAL-PRESSURE GAGE.

Patented Oct. 17, 1911.

and useful Improvements in Differential- Pressure Gages, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to gages adapted to be controlled by the diflerence between two pressures, and the object of the invention is to provide a gage of this type which shall be very sensitive to a small difference of pressure, less sensitive to a large difference of pressure, and incapable of being damaged by an overload or excess of difference of pressures.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described and particularly pointed out in the appended claims.

The accompanying drawing is a side elevation, partly in section, of so much of an apparatus embodying our invention as.is necessary to understand the same.

The rincipal features of the device, are incloseki in a casing C, said casing forming also, as will be hereinafter explained, an essential part of the invention. The casing is connected by two pipes P and P with a conduit H through which aofluid is supposed to be passing. This conduit is shown as what is known as a Venturi tube such device being well known in connection with fluid meters. The pipeP connects with the throat of the Venturi tube, while the pipe P connects with the up-stream portion of the tube or that portion from which the fluid is approaching the throat. As is well known in connection with such 'Venturi tubes, the pressure at the point where the in the spaces between the disks which we i will now roceed to describe.

In the simplest form ofthe invention the gage might consist of a single pair of corrugated isks or diaphragms J J, but in the a preferred embodiment illustrated we have shown five of such pairs of disks, two being illustrated in section and three in side elevation. The lower disk of each pair has its outer edge or flange bent over and crimped upon the outer edge of the upper disk of the pair as indicated at 1. In the center of each pair of disks and inside thereof are two thickened and relatively stiif center pieces 7' j, the upper one of each pair of center pieces having a threaded nipple.v 2 to engage a threaded hole 3 in the lower center piece of the next pair of disks above it. The nipple, however, of the uppermost center piece j enters a cap 4, while the lower center piece j of the lowermost pair of disks is coupled, as by a threaded nipple 5, with an opening in the bottom of the casing C with which opening the pipe P communicates.

To eifect tight joints between the different pairs of disks or diaphragms we interpose washers 1' there being also a similar washer below the lowermost pair of disks.

Through an opening in the cap 4 a rod or wire J 3 extends, said rod or wire having a head at its lower end inside of the cap. Said rod or wire J 3 leads through gland J 4 to the 'point or device where the accumulated motion resulting from expansion or contrac tion of the several pairs of disks will be transmitted to a suitable device which may be a pointer p cooperating with a scale S to indicate the conditions of expansion or con'- traction of the pair or pairs of diaphragms due to variations of the pressure inside and outside of said pairs of diaphragms.

The casing is pressure tight, and to said casing is led the fluid from the main, while the pressure from the throat is conveyed to the interior of the diaphra Owing to the fact that the structure 1s such that the greater pressure is outside of the diaphragms, any excess of such outside pressure will only serve to collapse the diaphragms until the center pieces 7' and y" contact with each other in' the manner illustrated in the drawing after which any further increase of outside pressure can have no efl'ect upon the diaphragms and conse-w supported disks exposed to the pressure p the difference of pressure can cause further motion.

It is to be understood that we do not limit ourselves to a plurality of pairs of disks or diaphragms, since the invention in its simplest form might embody only a single pair. But owi to the structure illustrated and described, the capacity can be increased to any amount by increasing the number of pairs of disks which are connected together and threaded holes of the center p1eces. It is also to 'be understood that. we do not limit ourselves to the scale and pointer employed for indicating the results of the operation of the gage, since any other device that may be desired may be substituted for the scale S and pointer p;

Having thus described our invention, what we claim is:

1. A device for measuring the difference of two fluid pressures consisting of a closed casing subjected to the greater pressure and containing a second casing having flexible walls subjected to the lesser pressure, the flexible walls being connected at their mary the nipples gins and arranged to "contact against each other as the difierence'of pressure increases, said contact progressing continuously from the outer ed e toward the center, whereby the increased external pressure will cause the contacting walls to support each other to prevent permanent distortion, and an exhibitor actuated by the movement of said flexible walls.

2. A device of the character described comprising a casing, means for supplying fluid under pressure thereto, flexible diaphragms supported in said casing and united at their margins, means for introducing fluid under pressure between said diaphragms, the walls of said diaphragms being adapted to contact continuously from their margins inwardly when the external pressure is greater than the internal pressure, whereby said excess external pressurefwill cause the contacting portions of said diaphragms to support each other to prevent permanent distortion, and an exhibitor connected to said diaphragms.

In testimony whereof we aflix our signatures in presence of two witnesses.

WALTER GEORGE KENT.

JOHN LAWRENCE HODGSON.

Witnesses:

H. D. JAMnsoN,

A. NUTIING.

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