US2659391A - Pneumatic accumulator - Google Patents

Description

Nov. 17, 1953 M. P. BERGER PNEUMATIC ACCUMULATOR 3 Sheets-Sheet 1 Filed July 2, 1947 INVENTDR mum: new Began BY Nov. 17, 1953 M. P. BERGER 2,659,391

PNEUMATIC ACCUMULATOR Filed July 2, 1947 s Sheets-Sheet 2 R M 5 R a 7% w. w m w m 4 w 5 m 5 y N 2 g 8 .l k 1 a 2 I H NOV. 17, 1953 M BERGER 2,659,391

PNEUMATIC ACCUMULATOR Filed July 2, 1947 3 Sheets-Sheet 3 Ty. Z

INVENTOR Mamas New CBERL'aE Patented Nov. 17, 1953 UNITED STATES PATENT OFFICE 2 Claims.

The present invention relates to pressure accumulators and similar apparatus of the kind in which pressure is exerted on the power transmitting gaseous or liquid fiuid by means of a source of energy constituted by a gaseous fluid under pressure and separated from said power transmitting fluid by a deformable partition for instance as described in my French Patent No. 842,835 filed August 31, 1938,

The chief object of my invention is to provide an apparatus of this kind which is better adapted to meet the requirements of practice than those used for the same purpose up to the present time.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:

Fig. 1 is a diagrammatic elevation, with portions in section, of a combination engine starter and compressed air accumulator according to my invention, for supplying liquid under pressure to operate said starter;

Fig. 2 is a part view analogous to Fig. 1, and showing elements thereof in another position.

Figs. 3 and 4 show, similarly to Fig. 2, in two different working positions, an accumulator made according to another embodiment of my invention.

Fig. 5 similarly shows an accumulator made according to a modification.

Fig. 6 is a separate plan view of one of the parts of the accumulator of Figs. 3 to-5.

Figs. '7 and 8 show, respectively in plan and sectional views, a portion of a cut ofi valve to be included in an apparatus of this kind and made according to another embodiment of my invention.

Fig. 9 is a plan view of a modified element of this device according to the invention.

Fig. 10 is a plan view analogous to that of Fig. 7 of a further modified device.

Figs. 11 and 12 are respective plan views of one of the elements of the device of Fig. 10, in still further modified forms. 1

By way of illustration, I have reproduced in Fig. 1 a system of the kind described in my above mentioned prior patent, which comprises:

a. The accumulator proper, constituted by a fiuidtight container l inside which is mounted a deformable bag or partition 2 (of rubber or another material) containing a reserve of compressed air or in communication with an external source of compressed air; 1

b. A reservoir 3 of power transmitting liquid, in combination with a pump 4 capable, through a suitable automatic control (operated for instance when the pressure, due to expansion of said bag 2, has dropped down to a given minimum in container I) of delivering this liquid under pressure into said container, where it occupies the annular space 5 between the wall and bag 2, said liquid being thus constantly subjected to the action of the pressure in said bag; and

c. Starters 6 (or any other apparatus to be controlled), including for instance two cylinders with pistons therein adapted to move under the action of the power transmitting liquid pressure, when this liquid is allowed by means of a valve 1 to enter said cylinders, the pistons acting for in stance on racks in mesh with a pinion fixed on the shaft to be started.

8 and 9 are an inlet conduit and an exhaust conduit respectively, the return of liquid to the reservoir 3 taking place through pipe [0.

In a system of this kind, it may happen that, when a starting operation requires an important and quick flow of fluid, the wall of deformable bag 2, upon expanding and moving toward the liquid outlet orifice II, blocks this orifice or the cut-oil valve associated therewith. This will tend to happen under the effect of the liquid stream suction due to the high local velocity of the liquid streamlines as they flow past the cutoff valve.

In order to obviate these drawbacks, I interpose, in the accumulator, betweenthe deformable bag and the outlet orifice, means for limit ing the velocity of the liquid streams, in particular by causing expansion to take place in a chamber of suitable dimensions, into which the liquid can be admitted through one or several orifices of sufiicient total section. v

For instance, as shown by Fig. 1, I provide at the end of the accumulator, preferably inside the removable end piece or chamber l2, a bellshaped casing l3 of sulficiently large diameter and into which the liquid flows laterally through a multiplicity of holes such as H.

If a out ch valve is provided between the chamber in which this casing I3 is positioned and the chamber in which deformable wall 2 is arranged, the suction effect will be reduced to a minimum on the one hand due to the plurality of saidby a bell-shaped piece l5 of large diameter, which surrounds casing I 3 and is subjected to the action of a return spring It, said piece l5 being provided with passage holes l1 in sufllcient number and laterally disposed. This valve includes a plate ll that fits laterally upon a seat I9, so as to constitute for deformable wall 2, when the latter expands to the maximum degree, a support free from projections capable of injuring it.

It willbe seen that On the one hand, bell 13, with its. lateral openings ll of relatively large total section, prevents any suction capable of causing valve I5 to be.- unduly closed,

n the other hand, valve l5, being of large diameter, does not risk causing a suction of deformable wall 2, and

Finally, said wall 2, at the end oi? its expan sion, rests upon a support of suitable shape preventing injury thereof (account being taken of the very high stresses applied thereto, which may, for instance, average 150 kgs. per sq. cm.).

Fig, 2 shows the. position assumed: by dei50rmalie wail2 in this last case. Advantageously andasshown by this figure, the valve is covered with a wider rubber or another flexible material such as 20, projecting therearound.

Thedevicemay further include means for limiting, displacements of valve l5 toward the accumulator, such as a screw with a projection 2| cooperating with a slot 22 provided in the valve wall. This screw will be tightened on a fiuidtight pad so as to prevent leakage.

Figs. 3 and 4 illustrate another embodiment, according to which the valve is constituted by flexible discs cooperating with a multiplicity of orifices so as to close them when deformable wall 2 is expanded to the maximum.

According to this feature, above bell-shaped casing l2. theretis provided a disc 23 (which may be fixed to this. casing at 24), having a convex curved face toward bag 2 and cooperating with one or several deformable plates (-of metal, or rubber, or any other plastic material), such as 25, 25, with orifices 21, 28 provided in said disc, and other orifices 2-9 in at least one of said plates, the whole being arranged in such manner that said orifices are closed when the plates are deformed so as to be applied upon said curved face of.disc.23.

Of course, the same result might eventually be obtained with a flat disc and curved plates, or with a disc and plates both of curved shape, but with different. curvatures.

The use of a multiplicity of plates permits of reducing the closing displacement of the outer edge of each of said plates to some tenths of a millimeter, while keeping suflicient sections of flow, as wide as possible in order to reduce the velocity of the liquid and to avoid suction of the plates before the liquid is wholly emptied.

A portion of this liquid therefore passes be-- tween curveddisc 23 and big plate 25, then tlnough holes 21.

Another portion passes between big plate 25 and small plate 26, then through holes 29 and 28.

The total section of flow is thus as high as possible. Consequently, the bag is not sucked in. owing to the low velocities of the liquid streams, which further are transverse to the axis, as above.

The plates will be made, for instance, of spring steel of a thickness of some tenths of a millimeter, so that they can bend and subsequently come back to their initial position; but any other material giving analogous qualities might be utilized.

Concerning the shape of the curved top part of disc 23, it is advantageously chosen in correspondence with the shape that must be imparted to big plate 25, when it is applied by deformable wall 2 against said disc.

I may further provide, between plates 25 and 26, a curved disc 30, the top curvature of which czegrrespends to the shape assumed by small plate When the accumulator is nearly empty of liquid and is still caused to deliver liquid, deformable wall 2 comes into contact with small plate 23 which is curved and comes to stop the passage holes 23 of the big plate. Then bag 2 comes into contact with the periphery of big plate 25, causes it to curve down and brings it into contact with disc 23, thus closing holes 21. This position is shown by Fig. 4.

The passages between disc 23 and plate 25 and 26, which are not quite fluidtight (metal on. metal) are: closed by therubher wall 2; which is fully applied on the whole.

I might also have. only one plate, such as 25', this-plate being thm solid that is to say without holes such as 29-.

arrangement of this kind is shown by Fig; 5, where it has been further supposed that disc 23 is integral with bell 13.

Besides, in order to give plate 25 or plates such as above mentioned a suitable dei'ormability, they should be provided with slits, for instance radially and near theperiphery, as shown at 31 on Fig. 8.

In. order to account for the fact that slits 3 I may allow liquid to leak past them, said plate or plates may be covered by a solid disc, for instance of foil,.such-.as 32 (Fig. 5)..

The system may be covered by a rubber disc such as 33 (Fig. 5).

According to still another feature of my invention, in systems including one or several platesintendedto be elastically deformed as above, the plates such as above described are replaced by a multiplicity of oblong elastic strips, fixed together for instance at their center, and overlapping one another.

Thus, according to a first embodiment shown by Figs. 7 and 8, Imake use of rectangular strips such as 34, provided in their centers with holes 35, these strips being for instance four in number to form a complete disc.

Eventually, they may be provided with lateral holes, as shown at 38 on Fig. '9, which permits of. reducing the suction effect of the liquid through the helm of supporting disc 23, by reduction of the. area of the strips opposite these holes.

In this case, the. angular overlapping of the successive strips may be more important, that is to: say the number of strips may be greater, so that the supplementary lateral holes are closed by the strips located above them.

According to another embodiment, shown by Figs. 10 to 12, the successive strips 34 are crossor star-shaped, being superposed in such manner that the solid portions of one star cover the intervals of the others.

Thethicknesses of the successive strips, crosses or stars may be diiferent'trorm one another. The last strip, to wit the bottom one, applied on supporting disc 23, will be the thickest one so as better to resist the suction effect of outlet holes 21, 28, the thicknesses of the other strips decreasing to the uppermost strip, which is the thinnest one.

Of course, the crosses or strips (Figs. 11 and 12) might, as above stated with reference: to Fig. 9,

be provided with supplementary holes 36, with a greater overlapping so that all the holes or intervals between branches are well closed.

The whole may be covered, as above, with a rubber pad 33, mounted on foil 32, or merely glued to a disk of fabric (or again merely covered with cloth on the side of the strips).

Such a system ensures a fiuidtight closing, and wholly prevents any injury of deformable wall 2.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An accumulator which comprises, in combination, a container, a flexible partition dividing the inside of said container into two spaces, one of said spaces being filled with a compressible fluid under pressure, said container being provided with an orifice adapted to connect the other space with the outside, whereby said second mentioned space can admit a power transmitting fluid or discharge it through said orifice, and cut-off valve means between the portion of said second mentioned chamber adjacent to said orifice and the remainder of said space, said cut-off valve means including a valve seat provided with holes and having a convex curved face toward said partition, and a plurality of elastically flexible plates fixed at their centers to said face, said plates angularly overlapping one another to constitute a composite disc deformable in response to deformations of said partition, said plates being normally fiat so as to be at a distance from said holes but to be applied thereon by said partition in the fully expanded state thereof.

2. An accumulator according to claim 1 in which said plates are in the form of elongated strips.

MAURICE PIERRE BERGER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 919,036 Langer Apr. 20, 1909 948,132 Clark Feb. 1, 1910 1,154,962 Bayles Sept. 28, 1915 1,634,949 Valley July 5, 1927 2,331,921 Mercier Oct. 19, 1943 2,342,356 Mercier Feb. 22, 1944 2,349,322 White May 23, 1944 2,385,016 Mercier Sept. 18, 1945 2,401,791 Overbeke June 11, 1946 2,427,287 Kochner et a1 Sept. 9, 1947 2,506,751 Trask May 9, 1950 FOREIGN PATENTS Number Country Date 521,783 Great Britain May 30, 1940

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