US2455539A - Joint construction - Google Patents

Description

E. A. WAHL JOINT CONSTRUCTION Dec. 7, 1948.

Filed D55. 29, 1944 INVENTOR.

' fies/v54 1414/.

ATZWRZYEY Patented Dec. 7, i948 i Allied Chemical Sq Dye Corporation a. corpora- Ihis invention relates to tight joints particularly adaptable f or use in connectiontwith communicating gas conduits. -In the practice of chemical processes involving the manufacture of gases and the handlingeof the same .in conduits usuallyof relatively large cross-section, it-is oftendesirable to provide a wgas lti-ght'joint in at gasline onesectionof which is movable with respect to another. As one lpracticaltexa-mple, in thel production of hydrogen .fiuoride gas,:fluorspar and sulfuric acid are reactedin a horizontal rotary furnace to form an :I-lF-gaswvhich isadischarged from one enduof the furnacethru a shortexit pipe which is axially 'alignednwith the horizontal axis oi the furnace F anol which is fixed to and rotates' with the furnace shell. This exit pipe is connected by a joint" to -astationary flue serving to iconductlthergas stream tto the subsequent gas purificationand HF recovery stages'oftheprocess. \Whilethe pipe rattaclhed; tow and rotating with the furnace; and the stationary; gas main are j designed so as :to be at least theoretically coaxial, it iswell known that in actual operation thesepipe sections are almost al-ways out :ottalignment to some greater org lesser extent. In the past, this circumstance has caused considerabletdifiiculty in connection with the construction of leakproofl joints between the fixed and rotating pipe sections, The usual packed gland type of joint has provedinade'quate, particularly after the apparatus has been inuusefor son c period of time. Tendency ifor gasleahage at the oint u has-l beenlso pronounced that; particularly in he manufacture of noxious gases, it has been the practice -almostuniversallyto operate at least the gas a generating portion of 1 the system undennegativepressurein order to prevent escape of harmful gases tothelatrnosphere andiavoid injury to workmen. Since commercially available .joint; constructions ofprevious design have not rbeen gasproof, the result of negative pressure operation has been infiltration of airthruthe connectingjoint to such 'an extent as to dilute the gas stream as much g-as 50% by volume. This difficulty requires the use of gas purification and recovery apparatus substantially larger than its objects and aaanaasiwm construction;.of ggas r Hpplication December 29, I944,-;Serial No. 570,34 i 1,4 Claims (crass-3 97.1)

appear from the following description taken? in connection with the accompanying drawings in whichFlg. 1 shows in section a preferredembodiment, and Figs. 2-3 show siinilar views of modifications. t l

The improvements of the invention are particularly adapted for use in situations in which one pipe section rotates and the other is stationary; both sections rotatebut one rotates at ahigher velocity than the other; andboth sections rotate but in opposite directions. i

To exemplifytutility of one embodiment time invention Fig. 1 illustrates application thereof in connection with manufacture of hydrogenfluoride gas. In Fig. 1, it indicates in section the gas out- .letend ofra horizontal cylindrical furnace'rotatably mounted on roller supports, one of which flappears at ll, Exit pipe section i is-fixed to and rotates with the furnace. this particular apparatusthe end of the main gas conduit M is stationary and-is held imposition by a support (5. Whilepipes Ed t-and Mappear coaxial ontthe drawing it will beunderstood that, because of irregularities arising from wear and tear and warping caused by heat, the axis of rotation of furnace H! is variable, and in operation the axes (of pipes it and M are almost always out of alignment which results in a substantially continuous eccentric rotation of pipe 13. Further, wear and tear on roller H and the associated track causes pipe 13 to have atsmall but appreciable axial movement relative to fixed pipe M. Both of these movements contribute to gas leakage at the connection between the pipe sections. In accordance prevent theingress of air if the system is operated .under negative pressure. l l

lfixedin gas-tight relation on the end of pipe I4, aslby welding, is an annulardiaphragm l8 providing a plane, non-flexible sealing face [9 of substantial radial dimension. Annular flange 22 isshrunk onto the outer surface of and rotates with pipe I3. Numeral24 indicates a generally annular shaped sealingmembrane the bead -26 of which is fastened to flange 22 by an annular ring 21 "and boltsZB; The bead 26 may he *OfvflIlY suitable length radially, depending upon "the particular installation. In cross-section membrane 24 issemi-circular andprovidesasealing facetll in the form of a convex arc. The entire membrane including the bead thereof is made of any suitable flexible and preferably abrasion-resistant material, for example, its construction and composition may be the same as those of a motor truck tire; thus it may be made of rubber with a fabric carcass. When the present improvements are used in conjunction with apparatus employed in the manufacture of gases such as hydrogen fluoride, the rubber constituent of the membrane is entirely of butyl rubber, or at least the bearing surface of the membrane is provided with a butyl rubber layer of suitable thickness, since it has been found that this material is particularly resistant to the acids such as hydrofluoric and sulfuric, and also possesses the required properties of flexing and resistance to abrasion.

Annular disk 33 is welded to pipe section I 3 and rotates therewith. The disk is formed with a plurality, e. g. four, of sleeves 34 into which are threaded studs 35 of such length as to permit substantial axial adjustment. A floating annular backing ring 38 is provided with a corresponding number of cylindrical sockets 39 each of suflicient inner diameter to receive loosely the end of a stud, and of suflicient depth to permit support of the ring 38 on the ends of the studs. One end of each of a plurality, say eight or twelve, of compression springs 4| is welded to the backing ring 38, and the other end of each spring is welded to the adjacent surface of an annular bearing ring 44. This ring is preferably of rectangular cross-section and of such width as to form an unobstructed annular air pocket 45 between the ring and the inner concave surface of the membrane.

In operation, studs 35 are adjusted to move the plane of backing ring 38 far enough toward pipe section |4 so that springs 4| and bearing ring 44 exert enough pressure on membrane 24 to form a gas-tight seal between the convex face of membrane 24 and the adjacent plane face IQ of diaphragm l8. Since membrane 24 and diaphragm l8 are connected in gas-tight relation to pipes l3 and I4 respectively, the seal formed by contact of sealing face 30 of membrane 24 and flange |8 closes off the annular port 41 through which gas normally egresses from or ingresses to the gas stream being fed into conduit M from furnace l0. The adjacent ends of pipes l3 and M are out of metal-to-metal contact, thus permitting relative axial motion, and the radial dimension of annular port 41 is substantial in order to permit a relatively large eccentric movement of pipe l3 with respect to conduit I4. The large radial dimension of diaphragm l8 permits substantial eccentric movement of the circle of actual contact between sealing faces l9 and 30. The convex sealing face 30, the flexible nature of the material from which the membrane is made, and the unobstructed pocket 45, all cooperate to permit, on eccentric movement of pipe 3, a slight rolling of the curved face 30 over the plane face 9 thus providing a relatively broad annulus of actual contact and avoiding any tendency of such faces to pull apart and break the seal. Being flexible itself and flexibly or hingedly connected to pipe l3, membrane 24 affords means for absorbing axial motion between pipe I3 and conduit |4. Bearing ring 44, because of its spring suspension, is readily movable universally, and hence changes in its vertical position do not interfere with maintenance of steady pressure of springs 4| holding the sealing faces in contact.

Numeral 50 indicates a trough which may be filled with water or other material serving to lubricate sealing faces I9 and 30, and to cool the flexible membrane assembly as it rotates with pipe l3.

The invention is subject to several modifications. For example, in Fig. 1 the relationship of the operative parts may be reversed, that is, diaphragm l8 may be fixed to and rotate with pipe l3, while flexible membrane 24, springs 4|, backing plate 38, the adjusting studs and their supporting disk 33 may be fixed to and remain stationary on pipe M. The sealing construction may also be applied to the solid residue outlet end of a furnace as well as to the gas outlet end. In this instance, as shown in Fig. 2, the only modification necessary is that pipe |3 be provided with a ribbon conveyor which discharges solid material into fixed conduit l4 terminating in a downwardly directed passage 56 provided at its lower end with a conventional air-lock not shown.

Fig. 3 illustrates adaptation of the invention to prevention of gas leakage at the connection between a reaction chamber and an associated rotary element. Numeral 60 indicates the side wall of a, stationary reaction chamber in which a gaseous reaction may be taking place. Wall 60 is provided with a circular opening 6| thru which projects a shaft-like member 63 which may be a rotary agitator shaft or a rotary electrode such as is used in some chemical operations. The shaft bearings, means for rotating the shaft, and insulating facilities if member 83 is used as a rotary electrode, are not shown. Bolted to the face of wall 60 is a sleeve 65 on the outer end of which diaphragm I8 is secured. The flexible membrane 24, stud supporting disk 33 and the intermediate associated parts are then fixedly attached to shaft 63 in the same manner in which such elements are secured to pipe I 3 as shown in Fig. 1. It will be noted that, since the diameter of shaft 63 is substantially less than the inside diameter of sleeve 65, the shaft and sleeve are arranged in non-gas tight relation, and that annular passage 66 provides a port thru which gas may egress or ingress. It will be seen'that the construction illustrated in Fig. 3 affords room for substantial eccentric and axial movement of shaft'53 without breaking the seal formed by diaphragm |8 and membrane 24.

I claim:

1. A pipe joint comprising communicating pipe sections having adjacent end disposed in non-gas tight relation and arranged to facilitate passage of a gas stream from one section into the other, at least one of said sections being rotatable about its axis, a diaphragm associated in gas tight relation with one of said sections and having a sealingface, a flexible membrane associated in gas tight relation with the other section and having a convex sealing face adapted to contact said first named face to form a gas seal, and resilient means for maintaining said sealing faces in gas tight contact whereby egress of gas from and ingress of gas to said gas stream is prevented.

2. A pipe joint comprising communicating pipe sections having adjacent ends disposed in nongas tight relation and arranged to facilitate passage of a gas stream from one section into the other, at least one of said sections being rotat able aboutits axis, a diaphragm associated in gastight relation with one of said sections and having a sealing face, a flexible membrane associated in gas tight relation with the other section and having a convex sealing face adapted to contact said first named face to form a gas seal, and adjustable spring actuated means for maintaining said sealing faces in gas tight contact whereby egress of gas from and ingress of gas to said gas stream is prevented. l

3. A pipe joint comprising communicating pipe sections having adjacent ends disposed in nongas tight relation and arranged to facilitate passage of a gas stream from one section into the other, at least one of said sections being rotatable about its axis, an annular diaphragm fixed in gas tight relation to and extending outwardly from one of said sections and having a sealing face of substantial radial dimension, a flexible membrane hingedly connected in gas tight relation to the other section and having a convex sealing face made of butyl rubber adapted to contact said first named face to form a gas seal, and adjustable spring actuated means for maintaining said sealing faces in gas tight contact whereby egress of gas from and ingress of gas to said gas stream is prevented.

4. A pipe joint comprising communicating pipe sections having adjacent ends disposed in nongas tight relation and arranged to facilitate pasfaces in gas tight contact whereby egress of gas from and ingress of gas to said gas stream is prevented.

EUGENE A. WAHL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,859,975 Malkin May 24, 1932 1,934,717 Johnson Nov. 14, 1933 2,038,855 Rosenblad Apr. 28, 1936 2,361,811 Badger Oct. 31, 1944

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