US3502300A

US3502300A - Diaphragm with tapered ribs

Info

Publication number: US3502300A
Application number: US563496A
Authority: US
Inventors: Derek John Harris
Original assignee: Saunders Valve Co Ltd
Current assignee: Crane Process Flow Technologies Ltd
Priority date: 1965-07-26
Filing date: 1966-07-07
Publication date: 1970-03-24
Anticipated expiration: 1987-03-24
Also published as: NL148394B; NL6609947A; DE1550506B2; DE1550506C3; GB1090868A; DE1550506A1

Description

March 24, 1-970 D. J. HARRIS DIA1?HRAGM WITH I'APERED RIBS Filed July 7, 1966 Inve-rzfol- D J Hal/+08 United States Patent 3,502,300 DIAPHRAGM WITH TAPERED RIBS Derek John Harris, Cwmbran, England, assignor to Saunders Valve Company Limited, Cwmbran, England Filed July 7, 1966, Ser. No. 563,496

Claims priority, application Great Britain, July 26, 1965,

31,774/ 65 Int. Cl. F16k 7/16 US. Cl. 251331 2 Claims ABSTRACT OF THE DISCLOSURE A diaphragm for a flow control valve having a conical side opening in the valve body running tangentially into the valve bore and the diaphragm having a hollow conical body with a flat peripheral flange with two diametrically opposed ribs upstanding from the body and tapering in height and base width.

This invention relates to fluid controlling valves of the kind having a substantially straight through bore and a seating formed by an opening extending from one side of the valve casing, of generally tapering form running tangentially into the valve bore, the closure member being a diaphragm of shape corresponding to the seating, moulded in a form corresponding to the closed portion of the valve and clamped at its margin to the valve casing. Valves of this kind are well known and a further development of such valve in which there is a markedly more rounded junction between the side and clamped margin of the diaphragm and in which this margin is not flat but continues the slope of the side through less steeply is also well known.

In these prior constructions of valve in order to give the diaphragm adequate strength with the necessary flexibility, it has been provided with a plurality, say six, of ribs on the back. In practice, the compressor has been shaped to match the back of the ribs and not the diaphragm because the latter would involve grooving the compressor, while by pressing on the ribs rather than the diaphragm between the ribs, pressure is concentrated and a better seal made to the relevant part of the seating.

It has been found that adequate strength of diaphragm can be obtained Without the ribs and in recent times the number of ribs has been reduced to two, arranged dia: metrically opposite, which come at the sides of the diaphragm (i.e. at the intersection of a mid transverse plane with the valve bore) because it is here that the seal is made from the tangent points up to the rounded margin of the casing adjacent the clamping surface. But these ribs have hitherto been made of rectangular section and under commercial production conditions the proportion of scrap produced is undesirably high, the. faults being in the region of the ribs which are produced by flow of the material in the mould. An object of the present invention is to reduce the proportion of scrap while retaining the advantages of the ribs.

According to the present invention, there is provided a diaphragm for a diaphragm type flow control valve having a conical side opening in the valve body running tangentially into the valve bore, said diaphragm comprising a hollow conical body rounded to hemispherical form at its apex and provided with a flat peripheral flange by which it is to be clamped in position in use, the concave interior surface of the body having two diametrically opposed ribs upstanding therefrom, such ribs tapering in height and base width to maxima at the base of the hemispherical portion of the body. The ribs taper from the maxima to nothing at the clamped zone and are arranged to come at the sides when in place in the valves,

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i.e. at the intersection with the valve of a mid plane normal to the bore of the valve, theribs are made of trapezoidal cross section with inwardly curving sides, well rounded corners and fillets at the junctions with the rest of the diaphragm. It has been found that with this form of diaphragm not only is the production of scrap reduced,

' but that if anything the valve is easier to open than with the known forms of diaphragm referred to above. Also that other things being equal, a tight closure can be made with rather less pressure, this easier closing being most marked at low line pressures.

It is believed that the reduction of scrap is due to the new cross-section of the ribs making the necessary flow of material in the mould easier, while as regards sealing, the new cross-section appears to give an effect somewhat akin to a narrow rib on the outside of the diaphragm while avoiding the susceptibility of such an external rib to damage by abrasivefluids.

It should here be mentioned that for reasons of economic production it has hitherto been impossible to provide the compressor with a contour which followed on over the rounded junction between the diaphragm clamp ing surface of the casing and the seating, and the compressor has been made straight sided.

As a result there is no direct pressure on the diaphragm in the region of the rounded junction when the valve is closed and the greatest tendency to leakage is in this region.

Various proposals have been made to deal with this problem but until recently the practical way of dealing with the problem has been to dimension the diaphragm so that though moulded in a form corresponding to the closed position of the valve, its axial length is a little short so that when the valve is actually closed the diaphragm is under axial tension and this tension has been relied on to hold the diaphragm sufiiciently tightly over the rounded junction to obtain tight closure without the necessity for imposing excessive pressure on the part of diaphragm against which the compressor actually bears. The diaphragm of the present invention is preferably similarly dimensioned in regard to axial length.

An example of diaphragm according to the present invention is illustrated in the accompanying drawings FIGURE 1 is a cross section FIGURE 2 is a plane view of FIGURE 1 FIGURE 3 is a detail section on the line III-III of FIG. 1.

The diaphragm illustrated comprises a conical portion 12 terminating at its apex in a hemispherically contoured part 13 to match the cross-section of the lower part of the valve bore. On the back of the diaphragm the centre part is bounded by a transverse flat 14. The mass of material thus formed provides material for the embedding of the head 15 of a screwed stud 16, by which attachment to the diaphragm is made. At the margin, the diaphragm has a sweeping curve 24 extending from the conical portion 12 towards the edge of diaphragm and in this particular example a circumferential rib 25 is provided which helps to ensure a tight seal when the diaphragm is clamped in the valve.

On the back of the diaphragm are formed two opposite radial ribs 26 which taper from a maximum height and maximum base width at the fiat 14 and die away to nothing at the clamped margin. As can be seen from FIG- URE 3, these ribs are of trapezoidal cross-section but sides are inwardly curved, the upper comers are well rounded and there is a good fillet joining each side at the base to the rest of the diaphragm.

It will be seen from the distribution of the. bolt holes 21 in FIGURE 2 that the diaphragm can only be inserted into the valve in two positions at to one another, thereby ensuring that the ribs come at the sides. In large sizes it is usual to make the diaphragm of circular outline with a larger number of bolt holes.

Correct positioning can be ensured by slightly unequal spacing of the bolt holes or by some similar device.

No reinforcement is shown in the drawing, but it will be understood that the diaphragm is reinforced with embedding fabric (which may engage the stud 16) in the well-known manner.

What I claim is:

1. A diaphragm for a diaphragm type flow control valve having a conical side opening in the valve body running tangentially into the valve bore, said diaphragm comprising a hollow conical body rounded to hemispherical form at its apex and provided with a flat peripheral flange by which it is to be clamped in position in use, the interior surface of the body having two diametrically opposed ribs upstanding therefrom, such ribs tapering in height and base width from maxima in the region of the hemispherical portion of the body to minima in the region of the flange, said diaphragm formed by moulding therein the ribs of trapezoidal cross-section with the convergent sides of the trapezium inwardly curved to facilitate release of the diaphragm from the mould in which it is formed, and, wherein the curvature of the convergent sides of the ribs is such that the top face of each rib is of substantially uniform width from end to end.

2. A diaphragm for a diaphragm type flow control valve having a conical side opening in the valve body running tangentially into the valve bore, said diaphragm comprising a hollow conical body rounded to hemispherical form at its apex and provided with a flat peripheral flange by which it is to be clamped in position in use, the interior surface of the body having two diametrically opposed ribs upstanding therefrom, such ribs tapering in height and base width from maxima in the region of the hemispherical portion of the body to minima in the region of the flange, said diaphragm formed by moulding therein the ribs of trapezoidal cross-section with the convergent sides of the trapezium inwardly curved to facilitate release of the diaphragm from the mould in which it is formed and wherein the curvature of the convergent sides of the ribs is such that the top face of each rib is of substantially uniform width from end to end, and wherein the curvature of the sides of the ribs is such as to provide a smooth transition at the junction of such sides with the interior surface of the conical portion of the body.

References Cited UNITED STATES PATENTS ARNOLD ROSENTHAL, Primary Examiner