US2132814A - Plaited packing ring - Google Patents

Description

Oct. 11, 1938. H, HEE ER 2,13%

PLAITED PACKING RING Filed July so, 1934 '2 Sheets-Sheet 1 ew e9 IN V EN TOR.

firm BY m 9. M

A TTORNEYS.

Oct. 11, 1938. H. T. WHEELER PLAITED PACKING RING Filed July so, 1954 2 Sheets-Sheet 2 INVENTOR.

Mm; BY i -S AM ATTORNEYS.

Patented Oct. 11, 1938 UNITED STATES PATENTOFFICE PLAITED"PACKING RING Harley T. Wheeler, Dallas, Tex.

Application July 30, 1934, Serial No. 737,579

8 Claims.

My invention relates to packing rings to be used in forming a seal along a moving member such as a rod, shaft or piston and pertains more particularly to packing rings made up of flexible,

porous material adapted to be fitted against the moving surface. p

It is an object of the invention to provide an annular packing, member in which the ring is folded or plaited so as to form a packing member better adapted to adjust itself to and obtain a better packing effect along the moving area, and in which the pressure fluid assists in such adjustment.

It is an object to form a packing ring of this character having various degrees of density toward the outer or inner side thereof to correspond to the conditions necessary to obtain the proper packing effect.

It is another object toprovide a ring in which there is one or more folds of the packing material and so construct the ring that it may be opened on one side so as to fit it about a rod;

shaft or similar member and still form a ring with overlapping ends which tend to form a close seal.

It is another object to provide a ring of this character in which the packing surfaces either at the inner or outer edge of the ring orthroughout its width, may be made flexible and porous in such manner as to resist hardening or gumming up of the ring and thus injure the effectiveness.

In the drawings herewith Fig. 1 is a central, longitudinal section through a stuffing-box of ordinary construction having one embodiment of my packing therein. I

Fig. 2 is a similar, longitudinal section through a piston working within a cylinder and having my packing rings employed thereon.

Figs. 3a to 37:. inclusive show a series of transverse sections taken through packing rings made in accordance with my invention and molded thereafter into different cross-sectional shapes.

Figs. 41' to 4m inclusive illustrate a plurality of cross-sectionsthrough packing strips folded in various ways in accordance with my invention.

Figs. 5a to 501 show a series of finished packing rings the same being perspective views of the ring illustrating the manner in which the rings are folded and adapted to overlap in two or more layers.

Fig. 6 is a perspective view of the finished ring folded with the open side toward the outer portion of the ring.

Fig. 7 is a similar perspective view showing a ring folded more than once and arranged to show the manner in which the ends of the ring overlap.

Fig. 8 is a diagram showing graphically the frictional effects obtained with this kind of packing illustrated therein.

Fig. 9 is a central, vertical section through a mold which maybe employed in producing a finished ring according to this invention.

Figs. 10 and 10a illustrate the manner in which a strip of porous packing material may be folded in the process of forming one of my improved rings.

Fig. 11 is a top view illustrating two different ways in which the strip may be formed into a circular packing member.

Fig. 12 is a somewhat diagrammatical view illustrating cross-sections of a single plaited ring.

Figs. 13 and 13a show in perspective the manner in which a blank of packing material may be folded to obtain a multiple plaited ring.

Fig. 14 is a top plan View of a ring after it has been partially formed.

' Fig. 15 is a diagrammatic view showing a section of a multiple-fold ring. y

Fig. 16 is a side view in perspective of a packing ring made up of two semi-circular portions fitted together to form the finished ring.

Fig. 1'7 is an end view of-a strip folded as indicated in Fig. 13.

My packing rings are adapted to be used in a stuffing-box about a moving shaft as shown in Fig. 1, or they may be used upon a moving member such as a piston disclosed in Fig. 2, and sealing against a stationary surface such as the cylinder wall.

In Fig. 1 I have shown a stufiing-box I having arod or shaft 2 working therein. The direction of the pressure flow is indicated at P. Within the stuffing-box are a series of annular packing members I 5 adapted to be compressed in the box by a gland 3 adjusted in position by cap screws 4 in the usual manner.

In Fig. 2, the piston is of the usual construction in which the head 8 of the piston has a flange at one end and a removable follower plate 9 at the other, so as to clamp between said flange and the plate a series of packing rings I l and I2, said rings II and I2 being separated by an adapter ring. or plate l3. This piston is mounted upon a piston rod or shaft 1, the follower plate being held in position by a jamb nut I0. In the reciprocation of the piston the pressure is alternately in opposite directions as indicated by the arrows P.

In Fig. 3 I have shown various cross-sections of finished packing rings, it being understood that the ring when folded can be then molded into various shapes. Fig. 3a shows the square shape; Fig. 3b, the cupped-shape; Fig. 3c, the V- ring type; and Fig. 3d, the conical ring. These shapes are mostly old. Shapes, shown in Figs. 3c to 3h, inclusive, are special shapes originated by me to be used in special situations where such forms are desirable. The form shown in Fig. 3e is called the frusto-conical; Fig. 3f, the concave cone; Fig. 39, the convex cone; and Fig. 3h, the concavo-convex shape. There are. many variations different from these forms. which may be designed.

In Fig. 4 I have illustrated how the blank strip of packing may be folded in accordance with the particular use to which itis. put. The inner surface of the ring is represented by the plane 1' V and the outer surface by the plane w. Thus the single plaited form shown in. Fig. 42' has the open portion of the fold toward the inner surface, while the form shown in Fig. 47' has the open side toward the outer surface. The form shown. in Fig. 4k is folded once and a half andis adapted to present the same surface. toward the outer or inner side. The form shown in Fig. Ll is the double plait withthe open ends presented: in.- wardly. The form shown in Fig. 4m is the multiple plait also arranged withthe open ends inwardly. These different forms of the ring will be later developed.

In forming a packing ring I contemplate using a quadrilateral of thin, porous material, and it is to be understood that various kinds of material may be employed, the most common being a fabric madev from cotton, asbestos. or other material, the most satisfactory for general service being asbestos.

In Fig. 10 I havev shown, in. the upper. View, a blank of absorbent material cut into. the. form of an acute angled quadrilateral which. is to. be folded along a central line indicated at 48.. Thisline is. slightly to. one side of. the transverse center thereof, so that when. the blank. of. material is folded along the. line 48. into. the position shown at 69, the upper edge will lie slightly inside. the lower edge- Also, it is. to be noted thatv when folded along the line 43 the end portion of. the upper fold has its edge 49a diverging. atv an. angle from the end of the lower fold 49d. This. isv due to the shape of the. original blank, asv will. be obvious.

Also at. the opposite end' of the. folded strip.

the end of the upper fold will project beyond the. end of the lower fold. The arrangement. of the lapped ends of the folded strip adapts the said ends. to interfi't when the strip is formed into. circular shape. The fact that. the. upper fold is. slightly shorter in. width than the lower foldenables the strip to be better formed into frustoconical shape as. will be. later noted.

When the strip has been thus folded into the shape shown in Fig. 10., it must be then distorted into a circular shape. In Fig. 11',v atthelefthandportion of the figure, I have shown. one manner in which the circular form may be obtained.

parallel areas as indicated between the two dotted lines it in Fig. 10. These areas are arranged to be stretched at the outer margin, as indicated at 5th in Fig. 11. The area b is of original width at the inner edge of the ring, but has been stretched at the outer margin to a greater length. Each individual area between the parallel lines is thus distorted by stretching the outer margin until it assumes the circular form, the ring being then formed so that the outer margin is indicated-by the line 0y and the inner margin by the radius 02.

In Fig. 12 the same radii are indicated at oy and 0's. At the right of Fig. 12 the strip 5| was folded with the open end inwardly while at the left thereof at 52 the open sides are presented outwardly. It will be seen that when the ring has been formed in the frusto-conical shape shown in Fig. 12, that the edge of the folds fall into the position in which both the outer and inner margins. of the ring are. in. cylindrical surfaces.

In Fig. 9 I. haveshown the manner in which the third step of the process is taken. The ring formed into circular shape as illustrated in. Fig. 11, is placed'in the mold 41 and arranged as shown at 49. against. the lower wall of an upper recess 49a in the mold. The ends of the strip are brought together and i'nterfitted with the ends overlapping in an. obvious manner. and the strip is then subjected to heavy pressure. by the. punch 63,. said punch having. a tapered area 4811 which is parallel with the lower wall of the die. Downward pressure exerted on the die will j'amb the ring, tightly into the die so as to give it a permanent irusto-conical set. In arranging the ring in the mold the short portion of the fold indicated' at 5030 in Fig. II will be arranged uppermost so that the ring may more easily assume the .frusto-conical shape which is desired.

InFigs 10', II and I2. I have illustrated the. single fold or plait for the packing ring. Where more than one fold is desired, the arrangement will be accomplished as shown in Figs. 12,. i4 and 1'7. Thus in Fig. 1'3 the blank 53 is marked. out with parallel lines. to indicate the position of' the folds and it is to be noted that the widths of the folds are not exactly equal. When the blank is. folded. along the lines. as indicated in the manner disclosed in Fig. 1'3, an end. view thereof. will be approximately as shown at 55 in Fig. 17. end 54 of the blank will be presented in a position. above the fold of the next adjacent lap in the strip as can be understood best from Fig. 17. This strip thus folded will be formed. into the circular shape indicated in Fig. 14,. by either of the methods previously described, but the stretching. process is illustrated. That is, transverse areas across the strip indicated by the dotted lines u in Fig. 13 are stretched along one margin as indicated at d in Fig. 14, thus lengthening the outer edge of the strip. This process being conti'nued the full length of the. stripdistorts the strip into. the circular shape. The particular shape of the. blank 53 leaves the ends of the strip stepped or terraced as shown in Fig. 14 in such. a manner as to overlap and interfit in an: obvious manner. The finished form of. the strip. is indiecatedat 51 in Fig. 15.

This form of ring is illustrated in finished form in Figs. 5, 6, and 7. In Fig. 6 the single lap. formof ring is shown, and in Fig. '7' the multiple l'apring is shown. The manner in which the ends of the ring interfit is best shown in these views; In Fig. 6- the dottedline IS -l6 The will contact with the end of the strip indicated by the lines I8-l9. On the other hand, the) outer fold of the ring indicated at l4--|5 will contact with the upper fold on the adjacent end indicated at I1|8. This will make a peculiarly close interfitting engagement between the ends of the ring so that they may be opened up to fit about a rod or piston, and when thus engaged in. operating position the ends will so closely interfit as to prevent any material amount of escape of pressure fiuid across the ends of the ring.

InFig. '7 the meeting edges of a multiple fold ring are illustrated. In this ring there are ends .on the various folds of the ring which are adapted to contact. with the ends of the corresponding folds on the meeting portion of the ring. Thus the edge 3840 will engage with the line 33-34; the edge 38-39 will engage with the edge 34-35; the edge 32-33 will engage with the edge 31-38; While the edge 3l32 will engage with the edge 36-41, corresponding thereto on the adjacent end of the ring. This manner in which the ends of the ring overlap is a feature of some importance which can only be accomplished with my plaited form of ring. It allows the ready assembly of the ring in the position in which it is to operate without materially impairing the sealing effect of the ring.

In Fig. 16 I have shown how thering may be made up of two! strips, each formed in; semi-circular shape and interfitted so as to form a complete ring. Where the rings are particularly large and are intended for heavy duty such a ring may be particularly desirable. It is obvious, however, that by forming such a ring in the manner described herein one-half 60 of I the ring may be made to interfit with the other torted out of their form as originally folded they will be curved on the arc' of a circle with a radius corresponding to that of the finished ring.

It is obvious that rings formed according to the different processes which have been noted, will have various degrees of density on different portions of the ring, and that the various laminated designs of annular conformation will produce widely varying amounts of contact friction. In Fig. 8 I have attempted to graphically illustrate the relation of friction to pressure which will be experienced. In this figure the ordinates OF show the measured pressure. The abcissas OP show the impressed pressure. The ideal relation of constant friction is indicated by the line 42-42.

All annular laminated rings such as forms it, o, and p of Fig. 5 give a proportional increased curve such as 4344, and other similar graphs indicated by the straight dotted lines; A helical, laminated packing" such as shown at q in Fig. 5 will produce a curved graph 45-46, and by the curved dotted lines 45a-46a. This diagram when produced from data obtained from the operation of a slow moving expansion joint requiring great reaction, would produce a curve 45a--46w. A fast moving compresser rod requiring low friction and a. reasonable reaction would result in the curve 43-44.

Rings made in plaited form as illustrated may be termed accordion rings and when adapted for use under high temperatures are ordinarily made of asbestos fabric. Such rings are preferably specially processed to, overcome faults of construction. When first installed without special treatment, all asbestos rings are found to shrink about ten per cent of their length when exposed to high temperatures of gas or steam. This is detrimental to continuous operation because at the first opportunity the box must necessarily be opened and the shrinkage in depth made up by the insertion of more rings. I find that about three per cent of theloss in size of the rings is due to the charring of the cotton twill which is used to bind the asbestos fibres during fabrication. About seven per cent is commonly supposed to be due to the evaporation of moisture which has been absorbed duelv to the humidity of the atmosphere. This is believed to be erroneous.

Chemically pure asbestos or magnesium silicate may be obtained in almost any form, but, the first cost of pure asbestos is prohibitive, and, also, it is too soft and flexible to be suitable for dependable molding operations. The impure commercial product is reasonable in cost, but is subject to ten per cent loss previously mentioned. It may be molded into any required shape by the process which I have described and will he readily in parallel laminations. I have found that the supposed moisture loss is due to the dehydration of several impure combinations with the.

asbestos, these impurities being very expensive to separate by the usual combing process employed in manufacture. Several forms of impurities'are found to be present, including hydrous silicate, iron oxide, potash, soda and a1umina. These impurities may be dissipated by heating, leaving a basis of magnesium silicate which is infusible.

I therefore prepare packing rings for high temperature usewhere shrinkage is undesirable, by heating them to a red heat after they have been formed into their annular shape. When cool they will be found to have shrunk and will be veny soft and flexible. The ,residue of the reduction under heat is often highly abrasive and is then removed by either shaking vigorously or subjecting the rings to a stream of compressed air. The rings are then recompressed in the mold and may be placed in service thereafter without experiencing appreciable shrinkage.

It isobvious that ordinary strip packing not folded in accordance with this invention, would not withstand that dehydration process as they would fall apart and not be suitable for shipment. I find that the laminations of my plaited type of packing will stand any degree of heat before or after use and may be removed from the stufiing-box many times without harm to the shape or to the fabric.

It is also desirable to use pure asbestos under conditions of moderate temperature at various times as where natural gas and compressed air are to be sealed off. Cements containing rubber or similar synthetic components, will harden under such service while pure asbestos remains flexible for long periods of time.

In Fig. 5 in the embodiment marked Q, I have shown a method of reducing the hydrates and other impurities in the asbestos at the points of contact with the surfaces to be sealed. Such packing may be formed by folding and processing in the usual manner and then an oxyacetylene torch 86 which is capable of developing high degrees of temperature is employed to treat the edges of the folds in the packing ring. lhe flame from the torch is directed along the ridges of the folds and the intense heat developed thereby quickly brings the fabric to an incandescent heat thus dehydrating and dissipating the impurities from the heated portions of the asbestos. A slow passage of the flame along the folds is all that is necessary. The i npurities are dissipated by the force of the torch and the ring may then be recompressed ready for service.

t is found that where the asbestos fabric is supported by a wire gauze as is sometimes done, as metal and the gauze may be oxidized by the application of the heat so that it may also be removed leaving a chemically pure asbestos at the folds along the movable surface. Such a ring is very elastic when subjected to pressure. responds quickly to pressure changes and to misalignment of the rod in the box, and is at the same time strongly reenforced at the portions of the folds which are removed from the area of friction. V

In my plaited or accordion type of ring, thus described, it will be obvious that the density of the rings will vary according to the manner in which the strip of fabric has been treated. When the strip is brought into circular form by crirnping or corrugating one marginal edge more ceply than the other, it is obvious that when this ring is placed in the mold and compressed the inner margin will be denser than the outer margin. It will also be denser than was the original fabric. However, when the ring is brought into circular shape by distorting one marginal edge to increase its original length, as has been described relative to Figs. 11 and 14, then the outer edge of the ring will be caused to be of lesser density than the inner edge, and will also be less than was the density of the original fabric.

These different density packing rings are those adopted for different purposes, and when arranged for use in a stuffing box the ring will be employed which is best suited for the particular sealing operation which is to be accomplished. By varying the number of folds and the original composition of the fabric various forms of packing may be developed suitable for use in various situations which may develop. in fact the mateial need not be entirely porous as the inventive idea may be adapted to other forms of flexible material.

My improved annular plaited ring is, therefore, adapted for use in various situations, depending upon the comparative density of the different portions of the ring and the number of folds which are employed. It has the advantage of being able to be easily inserted in position about a shaft and to form a seal because of the particularly effective manner in which the ends of the ring may interfit to form a close seal. Various other advantages will be obvious to those skilled in the art.

Having described my invention, What I claim 1; A sealing ring of the character described including, an annular strip of absorbent material folded into approximately equal folds, said ring being divided transversely to enable the same to be inserted about a cylindrical member, the line of division being stepped and the ends adjacent thereto being overlapped so that the ends of each fold will abut closely against each other.

2. A sealing ring of the character described including, an annular strip of absorbent material folded into approximately equal folds, said ring being divided transversely to enable the same to be parted at one point to be arranged about a cylindrical member, the endsof said ring where p rted being adapted to overlap and interfit to form a seal, the ends of each fold being staggered r lative to the ends of the adjacent folds and arranged to' abut when the ring is assembled.

3. A sealing ring of flexible, porous, fabric material folded transversely and divided along a single longitudinally inclined line, the crest of each fold lying in inner and outer cylindrical surfaces adapted to contact with a rod and a box.

A sealing ring of flexible, porous, fabric material folded transversely and divided along a single longitudinally inclined and stepped line, the crest of each fold lying in inner and outer cylindrical surfaces, the material of said ring varying in density from one cylindrical surface to the other cylindrical surface.

5. A sealing ring of flexible, porous, fabric material folded transversely and divided along a single longitudinally inclined line, the crests of the folds lying in inner and outer cylindrical surfaces, the end surfaces of said ring forming the frustrurn of a cone.

6. A. sealing ring of flexible, porous material folded transversely into annular accordion shape, said ring being longitudinally divided, the end faces of the folds of said ring lying in a conical surface, the ends. of each fold being inclined relative to the axis of the ring and to the ends of adjacent folds and adapted to abut each other when assembled,

A frusto-conical packing ring for sealing between a rod and the walls of a box including an annular strip of porous material folded into a plurality of approximately equal folds, the inner and outer margins of the folds being arranged to lie in cylindrical surfaces and the sides of said folds formed to lie in the frustrum of a cone.

8. A sealing ring for stuffing boxes, said ring being of flexible, porous material folded transversely in folds of approximately equal width, the said ring being divided longitudinally along a stepped line, the ends of the folds being adapted to contact each other, the crests of the folds on the inner and outer sides of the ring lying in cylindrical surfaces, and the adjacent faces of the folds being inclined relative to the rod and box.

' HARLEY T. WHEELER.

iii)

Images