Elastic diaphragm

A. H. MORIN elastic diaphragm

June 16, 1953

Filed Dec. 19, 1947

2,642,091

Sheets-Sheet 1

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June 16, 1953 a. h. morin 2,642,091

ELASTIC DIAPHRAGM

Filed Dec. 19, 1947 2 Sheets-Sheet 2 , fig .21. ^F,G -¹⁸·

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FIG 1θ· FIG 2o.

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FIG 17 //W£7V7Zie' ..

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Patented June 16, 1953

2,642,091

UNITED STATES PATENT OFFICE

2,642,091

ELASTIC DIAPHRAGM

Aiwrand™ Henri Morin, Montlucon, France

Application December 19,1.947, Serial No. 792,771 In France January 3,1947

137—793) form of diaphragm constructed in accordance with the present invention; ._

Fig. 11 is a similar view of a modified form of a diaphragm;

Fig. 12 is a fragmentary sectional view of a diaphragm constructed in accordance with the present invention;_

Fig. 13 is a diagrammatic representation of the formation of a: diaphragm according to the present invention;

Fig. 14 is another diagrammatic representation showing a further step in the formation of the diaphragm; ..

Fig. 15 is a longitudinal sectional view of the device of the present invention showing: the connection between the diaphragm and the rigid members; .

Fig. 16 is a similar view showing modified forms of the connection between the diaphragm and rigid members;

Fig. 17 is a longitudinal sectional view of a device constructed according to the present invention for actuating the lever;

Fig. 18 is a longitudinal sectional view of a device embodying the principles of the present invention applied to a valve;_

Fig. '19 is a transverse sectional view of the device of Fig. 21;...

Fig. 20 is a similar transverse sectional view of 30 a modified form of device;

Fig. 21 is a longitudinal sectional view showing a modified form of the present invention applied to a valve..

Referring to Figures 1 and 2 of the drawings, 35 it can be seen that when a thread a whose ends are fastened to pieces A and B is subjected to such forces as the forces P, which may be, for instance, at right angles to the thread, it tends to draw the pieces A and B nearer to each other. If 40 the thread is nearly rectilinear, the forces which tend to draw the pieces A and B nearer become very great, even if the forces P are. very small.

Suppose now (Fig. 2) that, according to the invention, a certain number of threads a, forming ⁴⁵ one or several networks, are fastened to the pieces A and B on which each of them exerts a pull under the action of elementary forces such as P: they will tend to draw the pieces A and B towards each other. If there is placed on the networks of threads a up to the pieces A and B, a fluid-tight film &amp; made of any elastic substance such as rubber for example, the wall thus made in the shape of a sleeve can be subjected to the 55 pressure of any fluid either on the inner or on the

Claims. (Cl.

My present invention has for its object an elastic diaphragm adapted to be subjected to the pressure of any fluid and adapted to transmit any change in the pressure of said fluid to a con- _Rtrolling device, such as measuring instruments, regulators, valves and similar devices.

The diaphragms already known and used have generally a corrugated wall as an accordionpleated bellows of metal or of any elastic substance enclosing often threads or fabric. In all the diaphragms made up of a heterogeneous substance (e. g. rubber and threads) in which threads are enclosed in the elastic substance, deformations are obtained through straightening of the threads. In fully metallic diaphragms, deformations are obtained through a variation of curvature of the walls or of the corrugated sui faces and a straightening of the metal.. In these conditions in order to avoid a lengthening of the ₂θ wall and damage of the diaphragm, either the deformations and above all the transmitted forces must remain limited or when these forces are large, they require the use of devices of large dimensions. ... 25

One object of my present invention is to provide an elastic diaphragm which is free of this inconvenience and is capable of working with large stresses, although having small dimensions and leading consequently to devices of moderate volumes. ...

Figure 1 is a diagrammatic representation illustrating the principles of the present invention;

Fig. 2 is a diagrammatic perspective view representing a further stage of the present invention; , .

Fig. 3 is a longitudinal sectional view of one embodiment of the present invention; .

Fig. 4 is a similar longitudinal sectional view showing another embodiment of the present invention;

Fig. 5 is a transverse sectional view of the structure shown in Fig. 3;. . . .

Fig. 6 is a longitudinal sectional view of a modified form of the invention; . .

Fig. 7 is a transverse sectional view of the structure shown in Fig. 6;

Fig. 8 is a diagrammatic perspective view of the thread-like elements of one embodiment of the present invention;

Pig. 9 is a similar diagrammatic perspective view showing a modified arrangement of the thread-like elements of the present invention;

Fig. 10 is a longitudinal sectional view of one

2,642,091 outer side of the sleeve or simultaneously on both sides of the wall.

Referring to Figures 3, 4 and 5, diaphragm i is composed of threads a covered with one or several fluid-tight elastic films b forming a sleeve. Threads a and film b are fastened to rigid members in the form of plates A and B by any suitable means ensuring fluid-tightness, for example by means of semi-circular clamps 2 and 2' screwed up by means of screws 3.

In the embodiment represented on Fig. 3, the plate B is solid whereas the plate A is provided with an orifice 8 through which any fluid under pressure can be introduced.

The fluid exerts a thrust F on each of the plates A and B which tend to be driven apart from each other. Moreover, the inner side of the diaphragm is subjected to a pressure which compels each thread to take a tension T. The resultant of all the tensions T of the threads applied to the plates A and B is on each plate a force U. These equal and opposite forces U tend to bring plates A and B nearer.

It must be pointed out that if the system is left alone, the diaphragm, being originally cylindrical for instance, becomes deformed and takes through the action of the inner pressure of the fluid, the shape of a barrel which grows more and more swollen in the middle until the forces that tend to draw plates A and B apart from each other balance the forces which tend to bring them nearer. At this moment the system is in equilibrium and F=Z7.

It should be further noticed that if at the beginning of its deformation the diaphragm is cylinder-shaped and made up of supple yet practically inextensible threads (placed along a generating line or a helix with a constant pitch), the forces U which tend to bring the plates A and B nearer are always greater than the forces F which tend to drive them apart. Consequently, plate B will draw nearer to plate A and during this displacement will be able to exert a certain amount of work and a force whose value reaches its maximum at the beginning of the deformation process.

It should be noticed that this force is limited only by the breaking of the threads and that, by increasing the number of the threads it is always possible to increase the force without altering the inner pressure of the fluid. If, for instance, the , plate A is fastened to the frame of a machine 5, £ J the plate B fitted with a rod 7 will be able to exert a pull on this rod and to cause a certain displacement of this rod. This result can be used for producing any motion or effort.

In the example of mounting shown on Fig. 4, 55 the diaphragm I consisting of the threads a and the film b is fastened, as explained before, to the plates A and B and put inside a vessel 6 to which the plate A is fixed. This vessel 6 receives through the orifice 9 a fluid under pressure which GO acts on the outer side of the diaphragm I which becomes deformed through a reduction of its diameter in its central part. Plate B is drawn nearer to plate A, Which causes the displacement of a rod 7 fastened to plate B and sliding through 65 the orifice 8 of plate A.

It should be noticed that the deformations of the diaphragm can take place even if the threads or cables are nearly inextensible. Only the fluidtight, elastic films connecting the threads to- 70 gether undergo a lengthening or a contraction.

It should also be noticed that if the original shape of the diaphragm is not cylindrical, it is possible to produce in the case of the device shown in Fig. 3, an action tending to drive the plates A 75 and B apart from each other. Such is the case when the forces U are weaker than the forces F previously defined.

Generally speaking it may be said that the ₅ original shape of a diaphragm, the number of threads or cables and the diameter for the plates A and B can be selected so that the force exerted by the plate B may take any direction and intensity desired.

Figure 6 shows a section along the axis of a third construction resulting from the combination of the embodiments of the diaphragms represented on Figs. 3 and 4. In this third embodiment there are two concentric diaphragms ! and lj i' which are fastened by any means whatever to the plates A and B (e. g. by such clamps as 2 and 2') provided with fixing rings A' and B'. The plate A has an orifice 8 communicating with the duct 8' through which a fluid undei’ pressure can _2U be introduced between the diaphragms i and

It can be seen how the clamps 2 and 2' can be adjusted, since they are locked by the screws 3 and 3' fixing the diaphragms I and I' to the flanges A' and B' of the plates A and B.

The working of the apparatus represented in Figs. 6 and 7 is as follows: under the action of a fluid under pressure introduced between the diaphragms, the threads of these diaphragms are tightened and if the sleeves of these diaphragms 30 ^were originally cylindrical, the deformation of the diaphragms would cause the plates A and B to come closer to each other. The diameter of the outer diaphragm I grows wider in the middle while the diameter of the diaphragm i' becomes _g. smaller in the central part.

Figures 8, 9, 10, 11 and 12 clearly show how this diaphragm can be made up of networks of threads linked together and covered with an elastic, fluid-tight wall or film.

₄₀ The shapes thus obtained can be of any kind, or of revolution and in this case the meridian profile can be of any kind, but it is convenient to lay the networks of threads on a cylindrical surface of revolution as it is simpler to make.

. Figures 8 and 9 show, for clearness’ sake, only 4 ) three of the threads a of the network forming the surface s. If the surfaces s are cylinders of revolution with an axis XX', in the case of Figure 8 the threads a are rectilinear and in the case of Figure 9 the threads a are helixes with a constant pitch. If there are several nets of helically wound threads, it is advantageous to give these helixes opposite pitches: some are. right-pitched, others left-pitched. Several sets of threads can be laid in a concentric manner.

Figure 12 represents a section perpendicular to the axis XX', showing the structure of a portion of a diaphragm. As an example, the networks of threads a and a' may be covered with the sheets b, b' and b made of any elastic substance, for example, rubber, and ensuring fluidtightness of the wall.

Two networks of threads are represented, but it is obvious that the number can be as great as desired according to the force to which the diaphragm is to be subjected.

The threads or cables of the diaphragm can be made of any substance, for example, cotton, rayon, asbestos or steel. The latter substance is particularly useful when it is desired to build small sized diaphragms capable of transmitting relatively high forces or when it is desired to use a substance having a small elongation. The film ensuring fluid-tightness and a connection between the threads can be made of any elastic

2,642,091 (j

Figure 16 represents two other modes of fixmg the'diaphragm. The rings A. and B ean be bonded to the wall of the ends of the diaphragm.. This adherence: to a metallic ring can be directly achieved, during; vulcanisation, in the case of a rubber diaphragm. The other mode of lastenmg consists inwidening out the end of the elastic diaphragm and in pressing it against the ring A by· means of a washer r locked by the nut e screwed on ring A (or B).

The diaphragm of the present invention, can be used to replace any diaphragm whatever or any piston. It can be worked by compressed air, water or oil under pressure, by steam or any other fluid.

It can serve as a thrust or pull member and the number of its applications is therefore very great.

Figures 17,18,19, 20 and 21 show as nonlimitative examples some of the applications of this diaphragm. . „

Figure 17 shows in. a section along the axis oi revolution of the diaphragm, how the rotation of a lever 10 about its axis ί I can be performed. For that purpose, the plate A. fixed, to one end of the diaphragm I is pivotally mounted on the frame 5 by means of the pin. i2. The other end is fixed to the plate B to which the end of the lever 10 is pivoted at 13. A helical spring 14 bears on the plates A and B which are kept in ’0 alignment by their telescoping parts Ί and 7' in the form of. rectilinear, hollow rods. The fluid under pressure is introduced through the orifices 8, 8' and 8”. The size and shape of the diaphragm can. be selected in such a way that 5 when the pressure of the fluid increases, the lever 10 turns for instance in the direction of the arrow Fl. When the pressure decreases, the spring pushes back the lever 10 in the direction of the arrow F2. In other words, it is possible to give : the lever 10 a reciprocating motion.

Figures 18 and 21 show how it is possible to produce the opening or the shutting of a valve 15 relative to its conical seat 15'. In the case of Fig. 18 a guided rod: 7 is fastened at one end to ,- thevalve 15, and at the other end to the plate B, which plate, in its turn, is fixed to the diaphragm

The plate A which is fixed to the other end of the diaphragm is fastened to the support 5 · .) by means of stiff rods 5'· A helical, spring 14 rests on the plates A and B. When the pressure of the fluid, introduced through the orifice 3 of the plate A, increases, the plate B comes nearer to A and lifts the valve 15. If the pressure of the fluid decreases: the valve tends to close and when the effective pressure of the; fluid is zero the spring 14 holds: the: valve 15 against its seat IB', so that there is no communication between the openings 16 and 17 of the valve.

(&gt;ό Figure 21 shows the application of a plurality of diaphragms which are concentric or arranged side by side in parallel.

It is possible to fasten two diaphragms to the end plates A and B as has been explained for the 0-, embodiment of Fig. 6. The rod 7 is fixed to the plate B and the valve 15. The spring 14 shuts the valve. The placing under pressure of the space comprised between the two diaphragms I and I' (by introducing a fluid under pressure 70 through the orifice 8) causes the compression of the spring and the opening of the valve 15 thus creating a connection between the openings 16 and 17 of thevalve.

Figure 19 represents the diaphragms I and I', 75 the rod 7, and the spring 14 in a section along substance such as natural or artificial rubber. An elastic substance mainly composed of silica, which is a good protection against heat and oxidation, can also be used.

Figures 10 and 11 show a special construction to fix the threads to the ends of the diaphragm. As an example, a network of threads d has feeen represented whose' ends are turned down, like hooks, around the rings t and t’ which can be metallic or made of any substance. The fluidtight and elastic sheets b and b' ensure flwatightness and can be turned down wito the threads around the rings t and t. . .,.

m the case of Fig. 11 the consruccion with hooking rings t and t' is exactly the same, but the threads and elastic sheets are so arranged as to close up one of the ends. In this case, the diaphragm is in the shape of a sack. The sackshaped disposition can be worked out wito nr without the rings t and f embedded in the elastic mass, the rings being replaced by inner or outer framings.. , .

in certain applications and also with a view to reducing the cost of_: these diaphragms, they can be made without the threads: σ being connected with such rings as t and t: Such a construction is represented in Figs. 8 and 9. In this case, the diaphragm is a part of a; cylinder of revolution which is obtained by rolling for instance a sheet of threads covered with rubber sheets or with any other elastic substance around a cylinder serving as a support during the making of the diaphragm.

Figures 13 and 14 clearly show, as an example, how these diaphragms can be built when the threads are to take, the shape of a cylindrical helix For that purpose, there should be rolled around a metallic tube d of an appropriate diameter a parallelogram-shaped piece of fabric a made up. of a set of threads or cables a. laid side by side and covered on both sides with a sheet of elastic substance, for example,, rubber. .. At the end of the rolling the two opposite edges of tne fabric butt against each other without overlapping, the edges of the gum-sheets can have a joint j in thin gum ensuring sealing.

This cylindrical tube d can serve as a support to the diaphragm during the vulcanisation if the sheets of elastic substance covering the threads are of. rubber. In· the case of the threads being ; laid along a generating line of the cylinder d, the fabric g is in the shape of a rectangle..:

The fixing of the diaphragm to the end plates can be ensured by means of clamps in several parts or split clamps in one part'. It can also be ensured, as is shown on Fig., 15,.m the case ox the threads of the: diaphragm being hooked, to rings t and t', either by means of a clamp 2 which compels the fabric to take the shape of a circular groove 9 of the ring A,: or by msaiis of , a ring h fastened to the flange B by bolts h'.

The ring li holds the enlarged end of the diaphragm by. pressing on the biconical ring Λ'' split in several pieces. These modes of fixing; the diaphragm to the rings A and B can be used, even if the ends of the threads are not fastened to such rings as. t and t'. . ...

All the devices known and used m engineering to fasten the ends of a flexible pipe to parts of machinery can be applied with a view to fastening the ends of the diaphragms to the rings A and B: for example, by means of metallic strips with •tighteners, by means' of split metallic clamps .forcing the diaphragm into a: groove after it has been put in place, and others.

2,642,001 a plane at right angles to the axis XX' of the rod 7. On Fig. 20, a section similar to that of Fig. 19 shows the diaphragms I when they are not concentric but arranged side by side, on the plate B and on parallel lines. These diaphragms can be arranged so that the increase of pressure causes the valve to shut rather than to open.

This diaphragm enables the valve or the movable element of a valve of any diameter to be remotely controlled by means of a small valve controlling the admission and the discharge of the fluid acting on the diaphragm.

The application of this diaphragm is particularly useful to replace the plane, conical or domeshaped diaphragms which are commonly used on certain valves. :.

It should be noticed that the action of this diaphragm is all the more sensitive and effective as its shape approaches that of a cylinder of revolution. This property can be utilized when it is desired to control automatically the expansion of the discharge of any fluid through a valve, the diaphragm serving as a driving member for controlling this expansion.

When it is desired to obtain a large displacement with these diaphragms without greatly varying the diameter of the latter it is possible to place a series of them end to end, separating them with rings fixing the extremities of two adjacent diaphragms. The displacement of the last ring equals the sum of the displacement of all the rings.

Lastly this diaphragm can be used in pumps to replace plane or dome-shaped diaphragms, or to replace pistons.

It can also be used in place of a spring, the stiffness of which can be adjusted at will and from a distance by altering the pressure of the actuating fluid.

Finally, the stretching of the central part or the diaphragm can be utilised to apply this central part against one or several orifices which can be closed by the wall of the diaphragm. In such cases the diaphragm is then directly used as a valve member.