US1292392A - Piston-packing. - Google Patents

Description

' R. ESNAULT-PELTERIE.

PISTON PACKING.

APPLICATION FILElMuLY 6.1911.

Patented Jan. 21,1919.

2 SHEETS-SHEETI .L dcwfoo/v da@ 6 w w R. EsNAuLT-PELTERIE.

FIS-ION PACKING.

- APPLICATION FILED JULY 5, |917. 1,292,392.

. \\\\\.4//A\` 7M l fli F PtBIlIed Jan. 21, 1919.

2 sHEETs-sHEET 2 JL f f ROBERT .'ESNAULT-PELTERIE, 0F PARIS, FRANCE.

IPISTON-IPACKING.

Specication of Letters Patent.

Patented Jan. 21, 1919.

Application filed July 6, 1917. Serial No'. 179,103.

To all whom #may concern:

Be it known that I, Bonner ESNAULT- PnLTnRrn, a citizen of the Republic of France, residing in Paris, France, have invented certain new and useful Improvements in Piston-Packings, of which the following is a specification.

The present invention relates to a plston packing device, specially intended for work at very high pressures.r

The principle of the packing forming the subject-matter ofthe present invention consists in utilizing, for the purpose of obtaining fluidtightness, rings or washers o f eX- tremely soft metal, which crush under pressure and become fitted with great exactness to the walls of the cylinder.

It is necessary however to point vout that this arrangement is not by itself sufficient to be applied to very high pressures, for it may bring about losses of power which in .certain instances would render the arrangement inapplicable.

In fact if it is desired to make a packing consisting solely of one soft metal, arranged in such a way that the pressure crushes it and applies it against the walls of the cylinder, one finds oneself caught between two opposite conditions :-l

On the one hand it is necessary in order that the fluidtightness may become primed, for the elastic limitI of the metal to be far below the pressure that it is desired to obtain, but in that case, when the pressure reaches itsv maximum, the metal is crushed to such an extent thatit works its way in between the cylinder and the hardmetal parts that are compressing it.

From this there results a jamming, a heating and a loss of power, which render certain applications impracticable.

The chiefv object of the present invention is to obviate this disadvantage, and it consists essentially of arrangingon both sides of the soft metal, two washers of` metal slightly harder, and then, on. both sides of these two washers, two others of metala little harder still, and so on, right up to the piston proper, which may be of bronze, cast iron or steel.

Experience proves that if the scale of hardness is suiiiciently graduated, there no longer occurs any spreading of the metals between the rubbing surfaces, and that under these conditions the operation is satisfactory.

v of the pressure.

In the event of the piston having to work in both directions, as forinstance, a piston which is, compressing a gas and which is subject to pressure not only during the compression stroke but also during a part of the expansion stroke, it is necessary that there should be on each side, starting from the soft metal, a range of metals gradually becoming harder.

Referring to the drawings Figure 1 illustrates such a packing device, designed for working in both directions.

F ig. 2, a packing designed'for working in one direction only, with a plunger piston.

Fi 3, a packing intended for working in one irection with a non-plunger piston. FFig. 4, a modification of the packing of ig. 5, a modication of Fig. 2.

Fig. 6, another modification of Fig. 1.

Fig. 7, an improved modification of Fig. 5.

In the arrangement that is illustrated in Fig. 1, the soft metal may consist for instance of a sheet of lead a, comprised between two sheets of tin or antifriction metal b, b, which are themselves comprised between two sheets of silver or gold c, c, which in turn are comprised between a sheet and a ieee of copper or bronze d, e.

he whole of these washers are threaded upon a rod f, which retains them by means of its ca g, and which is itself comprised in the axls of the piston it, where it is maintained by a transverse cotter i.

It goes without saying that to enable the packing to act the slotin the rod f throu h which the cotter z' passes should allow Sucient play or clearance for the cap g to be able to compress the washers under the It also goes without saying that the depth of the central cylindrical cavity in the iston 7L, which receives the rod f, shoul ybe greater than the length of the said rod, for the same purpose.

In view ofthe fact that the present packing device offers a frictional resistance which is greater in proportion as its surface of'contact with the cylinderlis itself greater, 1t is expedient, when applying it to a pump for liquid acting in one direction only, to reduce the said rubbing surface by arranging only one of the two sets of washers of decreasing hardness. This is what is shown in Fig. 2, in which the same letters designate force Lacasse the same washers and consequently do 'not require any fresh explanation, the only difference consisting in the fact that the piston 'mis of the plunger type.

In Fig. 3 the saine arrangement isv illustrated for1 a pump for liquid, having a nonplunger piston, and this also does not call for any further explanation. j

In applying the present device there may however arise a special case, viz: one in which the conditions of temperature or the chemical conditions do not leave such a well graduated scale of hardnesses available as might be desired.

In this case, in order to prevent the soft metal from working between the harder metal and the cylinder wall, it is desirable to utilize the arrangement illustrated. in Fig. 4, which consists in not making the obturating washers flat but of arrangingy them in such a way that the' washer of the hardest metalmeets to join against the face of the cylinder at an acute angle, the softv metal meeting at an obtuse angle equal to the supplement of the preceding angle, these two langles 'being further removed from 90o according as the difference in hardness between the two metals is greater.

This is what is illustrated in Fig. 4,. for a piston arranged as in Fig. .1, assuming that one has been compelled to include the lead washer directly between two silver washers.

Fig. 5 illustrates an arrangement equivalent to the preceding, applied to the arrangement of Fig. 2.

In the event ofI it being desired to compress a gas up to an exceptionallyhigh pressure it is advantageous not to put a single soft metal washer in the center of the packing but to arrange several soft metal washers separated from one another by slightly harder washers.

In Fig. 6 a piston similar to that of Fig. l is outlined, but comprising at its center a series of three lea'd washers separated by two washers of tin or antifriction metalfor instance.

Fig. -7 relates to an. improved construc tional form of the packing of Fig. 45, en-

abling a packing toV be obtained which isI more compact and more homogeneous and therefore more capable of resisting wear and less fragile.

The various superposed washers a, b, c, d have the faces that are intended to come into contact with one another cut to a V- shape all having the same degree of opening, 'in such` a way that the "said washersv can fit exactly into one another. r1`he upper vsurface of the irst washer a, formed of the softest metal, may be plain, and is preferably almost iush with the upper edge of the next washer b.

The inclination of the faces of the washers that are in contact with one another, and consequently the angle they make with the wall of the piston h, are determined as before according to the difference in hardne between the metals employed.

The various washers may advantageously be united to anotherI by welding so as to increase the compactness of the packing.l

What l claim and desire to secure by Letters Patent of the United States is 1. A piston packing for high pressure apparatus, said packing comprising several layers of metal of different hardness, the

t layer of softest metal having adjacent thereto theilayers of metal in the order'of their Olncreasing hardness, the metal of said layer of softest metal being adapted to be crushed against the sliding part against'which the packing bears.

2. A piston packing according to claim 1 further characterized by the layer of softest metal being on the pressure side of the packing. j

3. A piston packing according to claim 1 further characterizedby the layer of softest metal meeting the sliding part against-- which it bears at an obtuse angle and the metal layers inmediately adjacent said softest metal layer meeting said sliding part at an acute angle forming the supplement t of the obtuse angle referred to. A 4. A piston packing according to claim 1 further characterized by plural layers of softest metal and 'its immediately adjacent layer.

. 5. A piston packing according to claim 1 further characterized by the layers of metal being V-shaped in cross-section.

6. A piston packing according to claim 1 further characterized by the layers of metal being superposed [in series on either side of said layer of. softest metal.

In witness whereof l have hereunto signed my name in the presence of two subscribing witnesses. l

Witnesses:

CHAs. P. Pimsleur, HENRI CARTIER.

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