US3148953A - Titanium or zirconium lining structure - Google Patents

Description

SePt- 15, 1954 AsAHlKo GoTo TITANIUM 0R zxRcoNTUM LIN'ING STRUCTURE Filed Jan. 17, 1961 FGTB Inventor AJA/#Ko GOTO A Homey United States Patent() 3,148,953 'IlTANlUM @R ZllCNUM LINING STRUCTURE Asko Goto, Nada-ku, Kobe, Japan, assigner to Kobe Steel Works, Ltd., Kobe, Japml Filed lan. 17, 1961, Ser. No. $3,259 Claims priority, application Japan Aug. 19, 196? 1 Qlaiin. (Cl. 29-191) The present invention relates to a titanium or zirconium lining structure. More particularly, the present invention relates to mounting a titanium or zirconium liner inside a body made of another metal.

It should be understood that the term titanium or zirconium as used in the specification and claims is intended to mean not only pure titanium or zirconium respectively but also titanium base alloys or zirconium base alloys respectively. lt should also be understood that a body to which the titanium or zirconium liner is to be mounted according to this invention refers to any equipment made of a metal (such as soft steel, stainless steel) other than titanium and zirconium. Typical examples of such body are distillation towers, columns, reaction vessels, tanks and the like which are employed in the field of petrolio chemical and other chemical industries and various huid transportation and storage and which are desired to be rendered corrosion resistant by means of a liner.

Titanium, zirconium and their alloys are Well known to be excellent in corrosion resistant property, so that they have been used in the manufacture of various parts, articles and equipments, such as distillation columns for the purification of petroleum and various chemical reaction vessels and apparatus which are required to be anti-corrosive. However, this proposal has encountered difficulties in that titanium, zirconium and their base alloys are costly as compared with other conventional metals such as stainless steel, and are not readily weldable to other metals.

lt has been proposed, therefore, to mount a titanium or zirconuim liner inside bodies such as reaction towers or distillation columns made of another metal such as soft steel or stainless steel. However, this proposal has not fully been successful because titanium and zirconium do not lend themselves to welding. This drawback is particularly notable when a liner is to be applied locally or partly only on a portion of the body where corrosion esistance is particularly desired. Furthermore, there has been another diiculty that those portions of the liner which are not welded or are not weldable to the body are distended from the inner Wall toward the interior of the body (vessel, column and the like) when it is subjected to negative pressure.

Therefore, where it is desired to locally mount a liner only on the area where corrosion is particularly noticeable, it has been inevitable to insert a foil or leaf of silver, silver-manganese or the like between the wall (stainless steel, soft steel, etc.) and the liner and then to subject the assembly to seam welding. This operation, however, is very troublesome and diilicult, particularly when the diameter of the body such as vessel, column is relatively large. When the body is to be employed in the applications where it is subjected to a negative pressure, it has been necessary to fasten the zirconium or titanium liner to the body wall by means of a number of titanium (or zirconium) locking or set screws or the like and then to edge arc-weld the head of each of the screws to the Wall. However, according to this procedure, the number and pitch w aitaasa Patented Sept. l, 1964 of the screws required depends upon the thickness of the liner and the vacuum degree to which the vessel or column is subjected. It is very diflicult to determine the number of the srcews and the pitch of the arrangement ofthe screws. Thus, sometimes it is excessive so that the apparatus becomes unduly expensive, and sometimes it is less than actually required so that the liner is unstable under'the negative pressure. Furthermore, due tothe use of a number of screws the possibility of leakage is increased and the life of the apparatus is shortened.

Therefore, it is an object of this invention to overcome all these drawbacks heretofore encountered in mounting a titanium or zirconium liner to a body of another metal.

lt is another object of this invention to effectively mount a titanium or zirconium liner to a body made of another metal, with a minimum number of screws or without such screws so as to avoid the possibility of leakage and to lengthen the life of the body.

lt is still another object of this invention to mount a titanium or zirconium liner to a body made of another metal, in such a manner as to effectively avoid a distention or displacement of the liner when subjected to a negative pressure.

lt is still another object of this invention to provide a titanium or zirconium lining structure on a body made of another metal, said lining structure being rigid and strong and not adversely affected by pressure variation.

Finally, it is an object of this invention to provide a titanium or zirconium lining structure of the type men-v tioned above which can be easily accomplished by a person who is not skilled in the art of high grade welding or xing technique.

Brielly, the above and further objects of the invention.

are achieved by the utilization of a separate member and Without any direct and face to face integral welding between the body and the liner. Thus, according to this invention, the liner is superposed at the end portion on the body wall together with a separate ring or annular member, and the annular member and the liner end portion are xed together onto the body Wall by means of a screw, bolt or the like made of titanium or zirconium. This screw or bolt is welded to the liner. According to a preferred embodiment of the invention the liner is formed with a number of internally projected ribs or undulations at intervals longitudinally of the liner for the purpose of reinforcement and prevention of an inward distention or displacement of the liner. Alternatively or additionally, for the same purposes, a number of annular support members made of titanium or zirconium are welded on the liner at intervals longitudinally of the liner.

The invention, both as to the liner structure and method for accomplishing the same, together with further objetcs and advantages thereof, will best be understood from the following detailed description taken in connection with the accompanying drawings in which:

FlG. 1 is a longitudinal section of a part of a column or vessel body with a liner of this invention;

FlG. 2 is a view similar to FIG. 1 but showing another embodiment of the invention; and

FlG. 3 is a view similar to FIG. l but showing still another embodiment of the invention and various additional features of the invention.

For convenience of explanation, in the following description a liner is described as to be made of titanium,

3 coniurn, a titanium alloy or a zirconium alloy where the liner is made of these materials respectively.

The structure shown in FIG. 1 is a particularly useful to mount a liner only on a local area of a. column or vessel. Indicated with the reference numeral 1 is a column body Wall made of a soft steel or stainless steel. A titanium liner sheet 2 is placed along and in contact with the inner surface of the wall 1 and its lower end portion 2 is bent and removed from contact with the inner surface of the wall 1 so as to form a gap therebetween, into which gap an upper end portion of a separate annular or ring member 3 made of soft steel or stainless steel is inserted and tted. Preferably, the member 3 has a thickness approximately equal to that of the liner 2. Thus the lower end portion 2 of the liner 2 and the upper end portion of the annular member 3 are superposed together on the inner surface of the wall 1. The annular member 3 is placed along and in contact with the inner face of the wall 1. Through the superposed portions a set screw 4 made of titanium is threaded into the wall 1 so as to bond them together. It will be understood that there exist a number of such screws 4 arranged at suitable intervals along the inner periphery of the superposed portions. In FIG. l there appear four screws (one being in section). The head 4 of each of the screws 4 is arc welded to the liner and then brazed at 5. The lower edge of the liner 2 is brazed throughout its length at 6 to the adjacent face of the ring member 3. It has been found .that a satisfactory result is obtained when this brazing is carried out by using pure silver or a silver alloy. The lower edge of the ring member 3 is welded throughout its length to the adjacent face of the wall 1 as shown at 7. Furthermore, the ring member 3 is bonded to the wall 1 adjacent the superposed portion by means of a number of plug or spot welds 8 at intervals along the inner periphery thereof.

The upper end portion of the liner 2 may be of the structure same as that shown and described in respect of the lower end portion.

According to this lining structure, the liner is rigidly secured to the wall and is very stable. The brazed portion has a strength of 20-25 kg./cm.2. Since the brazing or welding can be carried out easily and completely by an edge arc torch or twin arc torch there is required no high grade technique and care.

The embodiment shown in FIG. 2 is particularly eifective in those applications where the lined body is exposed to a negative pressure. A titanium liner 12 to be secured or mounted on the inner surface of the body wall 11 is formed with a number of parallel inner periphery ribs or undulations 13 arranged at intervals longitudinally of the liner. The rib may have any suitable cross sectional shape. In the embodiment shown, it is a hollow semicircular shape in cross section. Here also, the wall 11 is made of soft steel or stainless steel. If desired, a reinforcement annular member 14 having a suitable crosssectional shape such as channel shape as shown and made of titanium is welded at 15 onto and along the periphery of the inner face of the liner 12 to obtain additional reinforcement. 'Ihe number and position of the ring(s) 14 may be determined in accordance with necessity.

The upper and lower end portions may be secured or bonded to the wall 11 in the same manner as shown in FIG. 1. However when the liner 11 is considerably long, the liner becomes considerably heavy due to the length and the provision of the ribs (and reinforcement rings, if provided). In such circumstances, and particularly when the apparatus is subjected to an extremely high negative pressure, the mounting structure shown in FIG. l may be not fully satisfactory. Therefore, it is preferable to employ, at each end portion of the liner, a support ring member 16 made of titanium. If desired, the ring member 16 is flanged as shown so that the flange may support a part (such as a filter, tray, etc.) of the apparatus, if any, within the body 11. The support ring 16 also serves to prevent an inward displacement or distention of the 4 liner 12 under negative pressure, and to secure the liner 12 to the wall 11 as described below.

At each end portion of the titanium liner 12, a bolt 18 made of titanium is threaded and fastened into the wall 11 through the liner 12. The bolt 18 is Welded to the liner metal at 17 The ring 16 is mounted on this bolt 18 through its opening and the assembly is tightened by means of a cooperating nut 19 made of titanium. It is preferable to secure a reinforcement plate 20 on the surface of the wall 11 opposite to those areas where the bolts 18 are extended. The plate 2t) is made of soft steel or stainless steel and is welded at 21 to the outer surface of the body 11. It will be understood that there exist a desired number of such bolts arranged at suitable intervals along the inner periphery of the superposed (wall, liner and support ring) portion.

By .this structure, a sufficient resistance of the liner to negative pressure is assured. The liner is rigidly and stably secured and is not adversely affected by a variation in vacuum degree within the vessel. It is not necessary to employ a number of titanium screws or the like so thatk a troublesome operation is avoided. The operation to secure the liner is quite easy because only a simple welding operation is required in welding the bolts.

In some instances, it may be desired to avoid the use of a liner formed with ribs or undulations. In the embodiment shown in FIG. 3, reinforcement ring or annular members are separately attached to the inside of the liner 12 instead of integrally forming the ribs thereon.

In this embodiment, each of the upper and lower end portions of the titanium liner 12 is secured or bonded to the steel wall 11 in the same manner as shown in FIG. 2. Between these ends, a number of parallel reinforcement rings are secured on and along the periphery face of the liner at intervals longitudinally of the liner. These reinforcement ring or annular members are made of titanium and are secured to the liner by means of welding. The ring or annular member may have various cross sectional shape.

The ring shown in FIG. 3a consists of two ring shaped plates assembled and secured to the line 12 by spot welding 23 so as to be a triangular shape in cross section. Along the ridge line the plates are spot welded together at 23. Since the ring is spot Welded at intervals the interior of the triangle ring is not comple-tely sealed or closed but can communicate with the interior of the vessel 1 so that the pressure is equalized.

In the embodiment shown in FIG. 3b the ring is L- shaped in cross section, and the ring shown in FIG. 3c is rectangular in cross section. In each case, the ring is secured to the liner 12 by means of line welding 24 along the edge adjacent the liner face throughout the length.

In still another embodiment shown in FIG. 3d, the ring is a circular tubular (circular in cross section) and is line welded at 24 throughout the length to the liner 11. In this case, it is preferable to provide a suitable number of small openings 25 on the tubular ring so as to equalize the interior pressure thereof with that of the vessel 11.

While some particular embodiments of the invention have been shown and described it will be recognized that various modifications will readily occur to those skilled in the art and it is therefore contemplated by the appended claim to cover any such modifications as fall within the spirit and scope ofthe invention.

What I claim is:

A hollow body structure, comprising, in combination:

(a) a hollow body of a ferrous material;

(b) a liner of a material selected from the group consisting of titanium and zirconium;

(c) a support ring member, said liner being superposed on the inner surface of a wall of said body with said support ring member;

(d) a separate ring member of a ferrous material, the

end portions of said liner being superposed on an end portion of said separate ring member with the end portion of said liner spaced from said Wall and References Cited in the le of this patent said separate ring member contacting said wall; UNITED STATES PATENTS (e) set screws of a material selected from the group consisting of titanium and zirconium, said set screws 4392266 Seme- --f APL 6, 1943 securing the superposed portions to said body wall; 5

and OTHER REFERENCES (f) weld means bonding said separate ring member t0 The Welding Journal, Fabrication of a Zirconiumsaid body Wall and providing a connection at the Lined RaCOll Vessel, Febllaf/ 1954, PP- 115-118- junction of the end portion of said liner and said separate ring member. 10

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