Abstract: The invention relates to a device for the collection, pre-analytic treatment, transport and grinding of solid samples, comprising a flask (1) having an opening (11) closed by a removable stopper (2), for receiving a solid sample. Said flask contains a pre-analytic medium (4), a plurality of balls (3) consisting of a solid material, and a means for holding the balls in place, that is designed to lose its effect when the flask is mechanically shaken or closed by the stopper, in such a way that, when the flask is mechanically shaken, the impact of the balls causes the grinding of the solid sample and the mixing thereof with the pre-analytic medium.

Abstract: A rotary milling system includes a rotatable body having a cylindrical portion and at least one variable diameter portion. The variable diameter portion is tapered toward an opening in a sidewall of the rotatable body a discharge grate. The body can include grinding media for abrading a product when the body is rotated. The product can be milled as a dry product or within a liquid medium. The tapered shape of the body urges milled product toward the opening and the discharge grate. The system can include a discharge housing surrounding the discharge grate and a conveying pipe in fluid communication with the discharge housing, with a valve disposed between the conveying pipe and the discharge to selectively allow milled product to be conveyed through the conveying pipe.

Abstract: Disclosed herein is a method and system for grinding fragmentary starting material, in particular ores, with a dry grinding system. An embodiment of the method includes the steps of determining the moisture of starting material for a certain period of time, preparing at least one screening stage, the cut point of which is selected depending on the determined moisture in such a manner that the moisture of a screen oversize does not exceed a predetermined moisture limit value when starting material having the determined moisture is fed to the screening stage, feeding starting material to the screening stage, transferring a screen oversize arising in the screening stage to the dry grinding system, and grinding the screen oversize in the dry grinding system.

Abstract: A tube mill has a body arranged for rotation about an axis of rotation. Material to be ground can be introduced into the body for comminution. The tube mill has an electric motor for rotationally driving the body. The electric motor has a rotor arranged around the body and connected to the body for rotation therewith and has a stator arranged stationarily around the rotor. The tube mill has a concrete element running around at least half the circumference of the stator yoke which is connected to the concrete element in such a way that forces acting on the stator yoke are transferred to the concrete element.

Abstract: A grinding process, in a grinding unit including a first shop including a first mill and a first separator, an outlet from the first mill being connected to an inlet of the first separator; a second shop including a second separator and a second mill, an outlet from the second separator being connected to an inlet of the second mill; the second separator being fed by the material coming from the first separator, wherein the first separator is operated at a tangential speed of 15 to 25 m/s and a radial speed of 3.5 to 5 m/s; and the second separator is operated at a tangential speed of 20 to 50 m/s and a radial speed of 2.5 to 4 m/s.

Abstract: A grinding mill comprising an essentially horizontally oriented, rotatable drum, a support bearing supporting the drum, and a riding ring connecting the drum to the support bearing is provided. The drum has a circumferential wall having a first end and a second end, a first end wall arranged at the first end of the circumferential wall, and a second end wall arranged at the second end of the circumferential wall. The riding ring is integrally formed with the first end wall.

Abstract: The invention relates to an agitator ball mill having a vertically arranged container, in which there an agitator that can be rotated about a vertical axis is arranged, and having at least one wear prevention element that can be fitted to the container inner wall with the aid of a fixing system, wherein the fixing system comprises a fixing pin and a fixing cut-out, which are arranged on the container inner wall and/or the rear side of the wear prevention element in such a way that the wear prevention element can be fixed to the container inner wall by means of a movement of the wear prevention element in a direction which forms an angle ?>0° with the vertical axis of the rotatable agitator, in that the fixing pin is guided into the fixing cut-out.

Abstract: A process for treating fly ash to activate the fly ash so that it may be used as a substitute for Portland cement, with the process including the use of a specialized rotary mill having variably sized and shaped media to increase the surface area of one fly ash component by grinding, avoiding milling a second fly ash component, while roughing up the surface of the second component to increase its surface area.

Abstract: A system and methods for recycling lithium-containing battery materials are disclosed. More specifically, the system and method use a high energy ball mill for recrystallizing, reordering and/or reconstituting the lithium-ion containing battery material. In one embodiment, the system for recrystallizing the lithium-containing battery material restores it to its original state of functionality.

Abstract: A trunnion seal assembly for joining a stationary inlet/outlet box of a ball tube mill to a rotational interior of the ball tube mill includes an outer ring component configured to be mounted to an outer wall of the stationary inlet/outlet box. An inner ring component is joined to the outer ring component substantially concentrically with the outer ring component. A flexible pad seal is configured to be joined to the outer wall of the stationary inlet/outlet box proximate outer ring component. The pad seal includes a first annular sealing surface. A mill head extension ring configured to be joined to a rotational mill head is located proximate to and substantially concentric with the inner ring component. The mill head extension includes a second annular sealing surface sealingly engaged with the first annular sealing surface of the flexible pad seal.

Abstract: A stirred ball mill assembly includes multiple vessels each having a body supporting sets of magnets rotatable with respect to the body. Each vessel defines an enclosed milling chamber, and has a stirring arm assembly extending in the respective enclosed milling chamber and connected for rotation with the respective sets of magnets. The sets of magnets and the stirring arm assembly are completely enclosed within the respective vessel. The vessels are configured to be stacked with one another so that adjacent ones of the sets of magnets are magnetically coupled with one another. A drive motor assembly has another set of magnets magnetically coupled with one of the sets of magnets of the stacked vessels. The drive motor can rotate the stirring arm assemblies within the milling chambers of the milling chambers of the stacked vessels via magnetic coupling of the magnets.

Abstract: The invention relates to a tube mill for the wet grinding of lumpy material with a grinding cylinder, an inlet opening for inlet of lumpy material, means for addition of an aggressive medium and also an outlet opening (5), wherein the grinding cylinder has an internal lining of epoxy material.

Abstract: Methods for comminuting the pozzolanic material include (i) providing a comminuting apparatus including a rotatable drum and an agitation medium positioned within the rotatable drum and configured to slidably move along the interior surface of the drum when the drum is rotated (ii) introducing a pozzolanic material into the comminuting apparatus and operating the comminuting apparatus so as to create a static charge on the agitation medium; and (iii) comminuting the pozzolanic material in the comminuting apparatus by rotating the rotatable drum without causing the media to crush the pozzolanic material so as to yield a reduced-size pozzolanic material comprising a majority of particles having a substantially globular shape.

Abstract: According to one embodiment, a ball mill for working generally spherically shaped target particles into a flake-shaped end product is provided. The ball mill includes a milling tube, one or more milling balls disposed within the milling tube, and a vibration source that is positioned and adapted to move the milling tube such that its central axis follows along a substantially circular path. The continuously changing direction of the acceleration of the milling tube results in each of the milling balls following a respective, substantially orbital path about the milling tube's central axis. As the milling balls follow the respective, orbital paths, the milling balls come into contact with and transform the target particles into flakes. In a further embodiment, the ball mill may further include a virtual particle separator configured to route intermediate particles back to an inlet portion of the milling tube for additional processing time.

Abstract: A method capable of manufacturing, by using a ball mill apparatus, powdered tea having the same quality as that manufactured by using a millstone. By using the ball mill apparatus having synthetic resin pots, a powdered tea material and synthetic resin balls are sealed in the pot, and the pot is revolved or revolved and rotated on its axis to crush the powdered tea material.

Abstract: A tubular vessel is loaded with a combination of grinding media and a material to be ground. The vessel is capped to contain the grinding media and material therein. Grinding of the contained material is effectuated by reciprocating the capped vessel in a direction parallel to its longitudinal axis. The grinding media may comprise either a ball or a slug, and may further utilizing a plurality of balls, perhaps of different sizes. To increase volume, a plurality of vessels may be gathered together into a sample holder. The sample holder is them reciprocated in a direction parallel to the axes of the included vessels.

Abstract: A grinding mill has a rotating container (40) into which particulate material is fed. The container is rotated above critical speed to form a layer which is retained under high pressure against the container inner surface. Shearing discs (58) mounted inside the container induce shearing of the layer to promote particle fracture by shearing and abrasion in the pressurized layer. Fine ground material travels axially to the container discharge end (64). In one form of the invention, the container is rotated at sufficient speed to form a series of solidified zones (70) alternated with stirred zones (72) next to non-rotating shearing discs (58). These solidified zones act as solid discs rotating with the container.

Abstract: Method and device for fine grinding of mineral particles A method for fine grinding of mineral particles consists of producing pellets (38), made from steel with a high carbon content, or cast iron, by means of atomisation with a granular size range less than 15 mm and mixing the pellets (38) with balls (36), made from steel or cast iron with dimensions between 20 mm and 120 mm, in a rotating grinding mill, the proportion by weight of pellets (38) depending on the granular size of the mineral particles for grinding and the desired reduction ratio.

Abstract: A method for fabricating a gearless grinding mill motor includes fabricating a plurality of linear stator portions and assembling a grinding mill stator from the linear stator portions.

Abstract: A low-fiber method for obtaining a fiber material (21) that is suitable for use as a raw material for insulation purposes, for the production of fiber mattresses or as a filing or padding material, from the fruits of poplars, willows, composites or similar plants. The closed fruits of said plants are dried and/or opened using an air flow and agitated in a treatment chamber (17), whereby the fiber material (21) contained in the fruit capsules (19) is substantially separated from the other constituent parts of said fruits.

Abstract: This invention relates to the mill wherein balls which are loading members in a milling chamber are made to move reciprocating motion certainly in the axis direction of a revolving shaft in addition to vertical motion so that a mass of objects can be milled in a short time, and which comprises of: a drum body providing an introduction inlet on one end thereof and the exhaust outlet on the other end thereof; a revolving shaft running through the inside of the dram body in the axis direction of the body; division members mounted on the revolving shaft with tilted angle to the vertical of said shaft dividing the inside of dram body, and forming plural milling chambers communicating through mutually in said dram body and pleural loading members for milling charged in said milling chamber, wherein said loading members repeat raising and falling by rotating said division members and move with reciprocating motion in the axis direction of the shaft.

Abstract: A mill for grinding loose materials, which comprises a closed container provided with at least one opening for introducing and removing the materials and has, at its two poles, a first coupling shaft and a second coupling shaft articulated thereto, a fixed frame which has centering elements for said first shaft and supports a driving shaft which is actuated so that it can rotate continuously, a flange which is fixed to said driving shaft and has eccentric elements for supporting said second shaft with a rotary coupling element interposed, said eccentric elements being adapted to make said second shaft perform a substantially circular orbit.

Abstract: A grinding mill has a rotating container (40) into which particulate material is fed. The container is rotated above critical speed to form a layer which is retained under high pressure against the container inner surface. Shearing discs (58) mounted inside the container induce shearing of the layer to promote particle fracture by shearing and abrasion in the pressurised layer. Fine ground material travels axially to the container discharge end (64). In one form of the invention, the container is rotated at sufficient speed to form a series of solidified zones (70) alternated with stirred zones (72) next to non-rotating shearing discs (58). These solidified zones act as solid discs rotating with the container.

Abstract: A mill in a coal-burning utility electrical power generation plant has a rotary drum for pulverizing coal, and has a mill head at an axial end thereof. A stationary divider plate divides the mill head into an entrance receiving coal, and an exit discharging pulverized coal dust. An openable door on the mill head is moveable between a closed position and an open position. The door in the closed position is intersected by the rotational axis of the drum and has a lateral dimension transverse to such axis and greater than the inner diameter of the mill head. The door in the closed position spans the divider plate and closes both the entrance and exit of the mill head. The door in the open position exposes both the entrance and the exit. The divider plate may be removed by withdrawing it axially through the door opening without cutting the divider plate into multiple sub-pieces.

Abstract: In accordance with a preferred embodiment, a rolling-type planetary ball mill apparatus for producing nanometer-scaled powders is disclosed, the apparatus comprising (a) a main rotary wheel comprising supporting members, (b) a plurality of mill pots which are revolvable by receiving a rotational force from the main rotary wheel through their corresponding supporting members, and are disposed around the main rotary wheel with substantially equal distance between one mill pot and another, each mill pot comprising a tiltable pivotal shaft having rotary coupling means so that the pot can also rotate about its own axis, each pivotal shaft having one end being supportably connected to its corresponding supporting member of the main rotary wheel; (c) motor means in drive relation to the main rotary wheel for providing rotational forces thereto; and (d) a non-revolvable counter-acting supporting ring disposed coaxially with the main rotary wheel and in the close, working vicinity of the mill pots; each tiltable pivot

Abstract: A mill for grinding and/or mixing a material. In one presently preferred embodiment of the present invention, the mill includes a first container rotatably mounted at a first end of a gyration arm. The container rotates about a first axis, and the gyration arm rotates about a second axis. The mill may further include a second container mounted at a second end of the gyration arm. The second container is rotatable about a third axis. As the gyration arm rotates about the second axis, the containers move with the gyration arm. In addition, the containers themselves rotate about their own respective axes thereby greatly enhancing the forces within the containers effecting the grinding and/or mixing. A first motor may be used to rotate the gyration arm, and a second motor may be used to rotate the containers about their respective axes. The mill may be operated in a continuous mode or in a batch mode.

Abstract: The present invention provides a pulverizer which can readily miniaturize a whole pulverization apparatus including the pulverizer and can be used for various purposes such as grinding aggregate or pigments, polishing decorative stones or pinballs, and mixing and stirring liquid of high density. The pulverizer is formed by a hollow rotator rotating with an article to be pulverized introduced inside and a pulverizing medium consisting of a necessary number of members, and pulverizes the article by up-and-down motions of the pulverizing medium as the hollow rotator rotates. The hollow rotator is provided with apertures formed on its outer surface at necessary portions which communicate inside to serve both as inlets and outlets for the article.

Abstract: A fine powder heat treating apparatus which includes a container rotated by an electric motor, a quantity of rolling media disposed in the container and a heater provided for heating the container and the rolling media, wherein the rolling media are mixed with each other as the container is rotated and a finely powdered raw material in a fluid state containing fine powder and a liquid component is supplied from a raw material discharge pipe.

Abstract: A process and an apparatus for separation of relatively volatile from non-volatile material, typically an organic component of agglomerate waste material from an inorganic solid component of the waste. The process includes milling material in a container partially immersed or floating in a bath of molten material to break up the material, typically an agglomerate, and thermally releasing the relatively volatile component as vapor therefrom. The apparatus relates to a desorption vessel at least partially immersed in a molten tin bath for heat transfer from the bath to the interior of the vessel for desorption of the relatively volatile component from such material.

Abstract: A mobile fluorescent lamp digesting system which crushes, cleans and classifies various lamp components into distinct groups i.e. clean glass, phosphor powder and metal end-caps, utilizing a crusher fan mounted inside a screen drum which is mounted on single rotating axis. An air knife is directed into fractured material during processing further enhancing cleaning action. The system is operated under negative air pressure to collect any ambient phosphor dust and or mercury vapor via a two stage filtering arrangement. First stage filter media is resistant to plugging by fine dust. The second stage is activated carbon media to collect metallic mercury vapors. Classified components are neumatically transported into collection chambers or drums after processing is completed for easy handling.

Abstract: A ball mill for use in mechanical alloying and grinding comprising a plurality of ferromagnetic balls within a spherical or cylindrical chamber or cell of a paramagnetic material. The chamber has a substantially horizontal axis of rotation. At least one magnet is mounted outside the chamber to produce a magnetic field within the chamber. The magnet is physically moveable, relative to the chamber, between a plurality of locations on an arc centered on the axis of rotation of the chamber.

Abstract: A method and apparatus for recycling wallboard employs a tumbling barrel for receiving wallboard pieces and metal weights. The tumbling barrel is sealed and the barrel is rotated so as to drop the weights against the wallboard. Once the materials are separated into gypsum and relatively large pieces of paper, the barrel doors are opened and the materials are transferred to a vibrating conveyor including a number of filtering screens for segregating the gypsum into consistently sized particles. A screen across the conveyor prevents the paper from continuing beyond a trap point. A chute transfers the paper particles to a paper collection bin while various sized gypsum particles are collected at the end of the conveyor in several bins according to size.

Abstract: The invention relates to a dispersing process in which a mill base consisting of solids and of a liquid phase is conveyed through a stirred ball mill containing a grinding medium, energy is supplied in this stirred ball by rotating rotors, and the solids are dispersed, and wet with the liquid phase, wherein the rotors rotate at such a high speed that the grinding medium moved by them forms, as the result of the centrifugal force, a rotating grinding medium charge which is in contact with the inner wall of the stirred ball mill, a space which is essentially free of a grinding medium being formed in the center of this grinding medium charge, the mill base is fed radially into the stirred ball mill, flows radially through the grinding medium charge in such a way that a centrifugal fluidiesd bed is formed with respect to the grinding medium, and is removed from the space which is free of grinding medium through an apparatus for separating off grinding medium.

Abstract: The invention relates to a tube mill partition as the discharge or transfer wall. With a view to an improved air passage and a simple material flow regulation, in the case of this partition a substantially tubular central part is used, in that a rotary and/or wholly or segmentally axially displaceable adjusting ring regulates the material flow.

Abstract: A ball-tube mill in which an inclined wall dividing the mill into coarse and fine grinding chambers occupied by grinding bodies has through holes for the passage of the material being ground provided in a portion of contact of the surface of the inclined wall with the grinding bodies present in the coarse grinding chamber. The through holes have a length much greater than their width with their elongated side running in parallel with an outer contour of the inclined wall.

Abstract: A ball tube mill in which an inclined wall dividing a housing of the mill into coarse and fine grinding chambers is fabricated from rigidly interconnected rods forming therebetween through slots for the passage of the material being ground. Part of each slot in the area of contact of the inclined wall with the grinding bodies at the side of the fine grinding chamber has a width smaller than the part of each slot at the remaining portion of the inclined wall at the side of the fine grinding chamber.

Abstract: A ball-tube mill includes a rotatable drum enclosed at the opposite sides by bottoms having a charging port and a discharge port, the drum accommodating an even number of perforated walls having the form of an ellipse, arranged at an angle to the centerline of the drum, and offset along the like axes of the ellipse one relative to another to define milling chambers occupied by grinding bodies. The bottoms are inclined to the longitudinal centerline of the drum at an inclination angle equal to the angle of inclination of the perforated walls, each bottom and one of the perforated walls being inclined in pairs to the opposite directions, the bottoms and the perforated walls being successively offset along the like axes of the ellipse one relative to the other at an angle .beta.=360.degree.:n, where n is the total number of bottoms and perforated walls.

Abstract: A rotary-type mill is provided with a system for charging powder to a mill under seal from atmospheric air, the system being comprised of a sealable loading conduit and a valve assembly. The valve assembly, which controls the opening to the mill, is disposed in part in the sealable loading conduit, and is operable without breaking the seal to the atmosphere. In addition to permitting charging and operations of the mill in a protective environment, the system is designed for gravity-dependent essentially unencumbered vertical entry of feed to the mill and for minimization of the problem of wear of machine parts during operation of the mill.

Abstract: A centrifugal fluidized grinding apparatus having balls as a grinding medium therein, comprises a parting vessel having a vertical axis, composed of inner and outer vessel parts both forming a circumferential groove. The circumferential groove has a continuous and smooth surface and provides a completely open inner space allowing the grinding medium and starting material to move freely through any part of the entire area of the inner space without encountering any obstacles. The groove has a generally ovoid profile with an upper part thereof cut away in a vertically cross-sectional view taken along a plane including the axis. The ovoid has a longitudinal axis intersecting the vertical axis at a position over the parting vessel. The inner and outer vessel parts are mounted for relative rotation about the vertical axis, in such a manner that the inner vessel part is rotated while the outer vessel part is stationary, or the latter is rotated in a reverse direction.

Abstract: A rotary batch-type grinding mill for processing powder is provided with an improved system for discharging material under seal from the atmosphere. The discharge system comprises a sealable collection chute having a banana-like configuration secured on the mill shell at an outlet port in the shell and extending substantially parallel to the circumference of the shell, a grate which prevents discharge of the grinding media from the mill during unloading of material from the mill and an elastomeric faced sealing plate which covers the grate during operation of the mill. The sealing plate is operated from outside the sealed system so that discharge from the mill can be effected without breaking the seal and the sealing plate is so disposed that in the open position it does not interfere with the flow of powder out of the mill.

Abstract: The annular gap-type ball mill for the continuous pulverization in particular of hard mineral substances comprises a closed grinding container (12) driven rotatingly and accommodating a rotor (13) driven in opposite direction. The outer surface of the rotor defines with the inner face of the grinding container (12) a grinding gap (20) which may contain grinding pellets.

Abstract: A drive body (4) which is rotationally driven via a shaft (6) projects into a fixed housing (1) closed by a cover (2). The annular-gap-shaped grinding chamber (M) formed between the housing (1) and the drive body (4) is partially filled with grinding balls, for example to 75%, and grinding stock flows continuously through it. The grinding stock enters from a product inlet (8) via the inlet gap (7) into the grinding chamber and leaves the latter through the discharge gap (3) which does not let through the grinding balls.The grinding chamber (M) is continuously widened from the mouth of the inlet gap (7) up to a deflection point (U).This results in a better starting behavior and a substantially more effective grinding, because a considerably higher grinding ball filling ratio can be achieved at the same circulating time of the grinding balls.

Abstract: A gas swept tube mill has a rotary shell (1) supported on a bearing (5) by a slide ring (3), which is reinforced by a stiffening web plate (4). Ground material and gas pass out of the mill shell through a sieve plate (10) and openings (8) in a frustoconical connecting section (12) into a stationary casing (9). The wider end of the section (12) is of similar diameter to the shell (1), to which it is fastened, and the narrower end of the section (12) is fastened to a drive shaft (7) for rotating the shell (1).

Abstract: A ball mill comprising a horizontal mill casing provided with means of magnetizing-force generation which are identically constructed and equidistantly spaced electromagnets forming a plurality of electromagnet rows, fixed in space, equally spaced apart and extending from one end to the other of the casing within two angular zones fixed in space, first from 135.degree. to 180.degree. and second from 225.degree. to 360.degree., thus presenting a plurality of magnet columns in circular direction, and which is provided with a switching circuit network for keeping the electromagnets of the lowermost row in the second zone in energized state and energizing and de-energizing all other electromagnets alternately and cyclically in two groups, such that every electromagnet of one group is sided, in crisscross directions through row and column, by electromagnets of the other group.

Abstract: A shell structure of a heavy-load type rod mill including a barrel having an outlet port and with a plate thickness of t.sub.1, and a pair of trunnions having journals integrally formed thereon and with a plate thickness of t.sub.2, which trunnions are welded to the barrel. At the weld joining the barrel and the trunnion, the relationship between the plate thickness t.sub.1 of the barrel and the plate thickness t.sub.2 of the trunnion is t.sub.1 .ltoreq.t.sub.2 .ltoreq.2t.sub.1.

Abstract: The invention relates to a tube mill in which the cylinder of the drying chamber and the transition wall which it supports are divided centrally or a number of times in the axial direction so that this cylinder and the transition wall can be replaced without the grinding elements having to be removed from the grinding chamber.

Abstract: A liner for the outlet port of a rod mill including a cylindrical body provided on the peripheral edge of an opening of the liner and projecting outwardly through the outlet port to prevent a rod from exiting the liner. The projecting length of the cylindrical body on the side close to the end portion of the barrel of the rod mill is preferably longer than that on the opposite side.

Abstract: A multi-function barrel finishing machine includes a central work processing section which is supported by a tiltable main spindle from horizontal to vertical or to inclined positions, and vice versa, the central work processing section including a turret rotatably supported by the main spindle and a plurality of barrel containers carried by the turret and which are capable of both axial rotation about their own axes, and orbital revolution about the main spindle. A single machine construction incorporates the various functions provided by the individual machines such as the horizontal-type high-speed centrifugal or planetary revolving barrel finishing machine, vertical-type high-speed centrifugal barrel finishing machine, horizontal-type rotating barrel finishing machine, and tiltable-type rotating barrel finishing machine. Those functions may be selected and performed singly or in any combination, depending upon the particular work processing requirements.

Abstract: Solid particulate material such as cement raw material, clinker, etc., is finely ground, crushed or pulverized, by means of a rotatable generally vertically oriented container of generally inverted frusto-conical shape, and having grinding media such as steel balls disposed therein. The discrete particles of the material to be pulverized are fed into the upper part of the container as it is rotated about a central vertical axis, and egress of the resulting finely ground material by centrifugal force from the container to external collection is accomplished by the provision of slits in the inclined side wall of the rotary container. A fixed cover enclosing the upper part of the container is provided with inner guide vanes which are typically curved or of a vortical form. A preliminary coarse crushing mechanism may be provided, and this mechanism may be integrated with the rotary container, so that coarse crushing and fine crushing may be performed by a single device.

Abstract: A journal and end closure for a tubular vessel particularly a shell supported tubular grinding mill. The mill shell is conventional to the point of the journal. The journal and end closure are formed by a pair of spaced apart cylindrical members and a T-shaped ring member, each secured to one another in an end-to-end relationship by welding. An annular plate is secured by welding to the leg of the T-shaped ring member to form part of the end enclosure for the mill. The T-shaped ring member is made from a material with controlled sulphur and impurity levels. The two cylindrical sections are rolled so that the grain structure of the metal is generally parallel to the longitudinal axis of the tubular vessel. The dimensions of the T-shaped member are selected to prevent high areas of stress from being concentrated at the junction of the T-shaped member with the two cylindrical members and the junction of the annular member with the leg of the T-shaped member.