US2797907A - Fastener for bubble caps - Google Patents

Description

P. DE BIE FASTENER FOR BUBBLE CAPS July 2, 1957 2 Shee'ts-Sheet l Filed Aug. 17, 1954 FIG.

FIG.

INVENTOR:

PIET DE BI HS TTJRNEY July 2, 1957 I P, DE B15 2,797,907

FASTENER FOR BUBBLE CAPS Filed Aug. 1'7, 1954 2 Sheets-Sheet 2 'lOb Fls f Fla? INVENTOR PlET DE BlE HIS ATTORNEY 2,797,907 Patented July 2, 195.7

FAS'YENER FR BEUEBLE CAPS Piet de Bie, The Hague, Netherlands, assigner to Shell Development Company, New York, N. Y., a corpora- Y This invention relates to a fastener or hold-down for securing a bubble cap over an opening in a contacting tray deck,I e. g., a bubble tray or deck of a fractionating tower, and to the combination of such a deck with a bubble cap and the fastener. More particularly, the invention relates to a fastener that includes an upright stem or fastening bolt and a transverse support for engaging the edge of the opening and lower face of the deck when in place, said fastener being adapted both for insertion into and removal from the opening from a position above the deck without the services of a workman beneath the deck, and being frictionally retained to the de k against falling during assembly to and disassembly from the deck.

Various hold-downs for bubble caps have heretofore been described. One (U. Patent No. 2,338,928), includes a central stern and a transverse support having shouldered arms that are alternately provided with lugs at their lower and upper sides for engaging the lower and upper surfaces, respectively, of the tray deck and thereby securing the stem against both upward and downward movements. During installation, the hold-down is tilted and hooked into the deck opening to place all arms initially beneath the deck; the stem is then righted and raised with the stem centered in the opening. The arms that have their lugs at ti e top, having the` ends rounded off, ex inwardly upon engaging the edge of the opening so as to pass through the latter and thereafter spring outwards when their lugs emerge above the deck.

An important disadvantage of this construction is the dilliculty in removing the hold-down from the deck; this operation involves flexing the arms whose lugs are above the deck manually to pass the lugs downwards through the opening. lt is obvious that this operation involves a considerable amount of time and labor when applied to a distillation or scrubbing tower having a large number of bubble caps. Further, such a hold-down can be .used only on a tray deck presenting at the edge of the opening a deck thickness that corresponds to the vertical interval between the upper and lower lugs; hence decks of different thicknesses require correspondingly dimensioned holddowns.

Another hold-down construction (U. IS. Patent No. 2,443,812) uses an inverted Lil-shaped spring clip with out-turned lugs at the bottoms of the spring arms, the said arms pressing against the vapor riser for frictional support to hold the fastening bolt against falling during asn sembly and disassembly. One drawback of this construction is that the spring clip requires a vertically enlarged contacting surface, such as the inner face of a riser tube, and cannot, therefore, be installed in a simple opening in a plate forming a deck. Another drawback is that, because the arms of the spring clip terminate in lugs that engage the under side of the deck, the clip can be removed upwards from the opening only by detaching or bending the lugs, which must be done from a position beneath the deck; two men are, therefore, required for removing bubble caps held down with such clips.

It is an object of the invention to provide an improved hold-down for bubble caps that, as well as the bubble cap held thereby, can be installed and removed by one Workman from a position above the tray deck without the necessity of flexing any arm or the like by a special manipulation.

A further object is to provide a hold-down for bubble caps that can be installed within an opening in a plate-type of tray deck of any thickness, working only from a position above the tray, for centering or otherwise correctly positioning the fastening bolt or stem within the opening and frictionally securing the hold-down within the opening against falling during assembly and disassembly.

In summary, the improved hold-down comprises an upright fastening stem to the top of which the bubble cap is secured and a transverse resilient support secured to the stem and comprising a plurality of arms having shoulders providing lugs adapted to engage the under side of the deck, said arms having lateral retaining surfaces adapted for frictional engagement with the inner edge of the opening in the deck and having earn surfaces for flexing the support by engagement with the deck when it is moved upwards through the opening, all parts of the support above the said retaining surfaces being situated within a closed plane geometric ligure, such as a circle, that is smaller than the similar figure enclosing the several retaining surfaces, whereby the support is retained frictionally in the opening solely by the resiliency of the support. The geometric relation between the stem and support is such that the hold-down can be tilted and inserted into the deck opening from the top to bring the support entirely beneath the deck. The device is then moved to position the stem vertically and center it, and drawn upwards into the deck opening to flex the support inward and engage the retaining surfaces to the inner edge of the opening. The device can be removed from the deck by simply pushing it down to free the support from the edge of the opening, tilting it, and drawing it up through the opening.

Various embodiments of the invention are illustrated in the accompanying drawings forming a part of this specilication, wherein:

Figure 1 is a sectional view taken on a vertical plane through the diameter of the opening in a tray deck and showing a bubble cap fastened to a tray deck with the hold-down according to the invention;

Figure 2 is a bottom plan view, looking in the direction of the arrows 2 2 in Figure l;

Figure 3 is a sectional view taken on a vertical plane through the diameter of the opening and illustrating the insertion of the hold-down;

Figure 4 is a sectional View taken on the section line 4 4 of Figure 2 and showing the hold-down in operative position;

Figures 5, 6 and 7 are bottom plan views of three alternative constructions; and

Figure 8 is a perspective view of an arm of a support according to Figure 5 or 6.

Referring to the drawings in detail, and particularly to Figures 1-4, the bubble cap l is supported by vertical spacer plates 2 that are positioned in notches in the upper rim of a tubular riser 3. The bubble cap is situated over a circular opening 4 formed within a tray deck 5, against which the bottom of the riser 3 is seated to support the bubble cap upwardly. The bubble cap is fastened by a fastening stem or bolt 6 which is permanently fastened at the bottom to a flexible, transverse support 7, the said stem and support together constituting the hold-down. The top of the stem is threaded to receive nuts S which bear on a washer 9 for holding the bubble cap in place.

agregara' ThesupportI 7l (-see Figure 2) consists ofV four' hori' zontal, flexible arms formed by two resilient metal strips that are thin in relation to their vertical dimensions and are bent toward each other at their intermediate parts', atf which they are fastened't'o each other'and to the bottom of the stem 6, e. g., by welding. The arms thus form an tei-shapedy support, The outermost parts advantageously intersect the edge of the opening at an angle to the radius, as shown, so as to be readily defi'ectable inwardsin" the manner to be described presently. The'shape of the support, when in the relaxed state, prior to installation, isshown in chain lines in Figure'Z. The end of'each'armis shouldered to provide a lug 11 at the bottom thereof and alateral retaining surface 12 extending vertically from thel lug. A cam surface 13 extendsv upwards from the retaining surface and is inclined generally toward the steme6; thecam surface may bestra'ight, as" shown, orl rounded as shown in Fig. 8.

Referring to Figure 4, three steps can-be distinguished in the support in its installed position when'viewed in side elevation.: (a), The lowest'step is formed by the lugs 11, the ends of which may be circumscribed by a circle of diameter D1 which is larger than the diameter of the opening 4; hence, the lugs engagethe lowerfaceof the tray deck to hold the stem 6 down and secure the riser 3 and bubble cap 5 when the nuts 8 are tightened. (b)

The second step is fonned'by the retaining surfaces 12,v

which fall within a circumscribed circle of diameter D2 equal to the diameter of theV hole 4. Prior to being locked inplace, i; e., in aV resiliently released condition as-shown in chain lines in Figure 2, the diameter D2 of the circumscribed circle enclosing the retaining surfaces 12 exceeds slightly that' ofthe opening 4. (c) The third step, formed by the cam surfaces 13, has circumscribed circlesof diameters that diminish towards the top tov a; limiting diameter D3 which is much smaller than the diameter ofV the opening 4, bothin thelocked and relaxed positions ofthe. support. It followsY that all parts of the support above the vertical retaining surfaces 12 are situated'within a circlethat is smaller than the circle enclosingl the retaining surfaces.

Installation of the hold-down and mounting of the bubble cap can be carried out in the following manner:

The operator, working above the tray 5, inserts the hold-down into the opening 4 with the stem 6 inclined to the vertical, as shown in Figure 3, to hook the ends of two parallel arms 10 atv one side of the stem under the tray and then swings the device to move the stem into vertical position so that the support-7 is entirely below' the tray. He then centers the stem approximately and pulls up on it. Engagement of the cam surfacesV 13 with theeinner edge of the opening 4-centers the stemaccurately and causes flexure of the arms from the chain line positions to the solid line positions (Figure 2), which reduces D2, the diameter of the circle enclosing the retaining surfaces 12, toa value equal to the diameter of the opening 4. When the lugs 11 engage the under side of the tray deck 5 the supportv 7 is resiliently locked to the deck. The stern 6 may now be released without its falling through the opening 4, after which the riser 3 with the spacers 2 and the cap lare placed over the opening' and around the stem 6. The upper part of the stem then extends through the cap 1 and the washer 9 and nuts 8 are applied.

When dismantling the bubble cap, the nuts 8 and washer 9 are detached and they capand riser are lifted and removed, while the stem 6remains locked in the opening 4; the'reafterthe hold-down is removed with a' continuous motion' of the hand, which includes a downwardmovement to movefthe support entirely beneath thedeck, tiltingv theV hold-down, and lifting it, in reverse of-v themovements described previously in connection with.Figure 3.

The support 7 may also be constructed in various-ways; care should, however, be taken to insure that it can pass throughtheopening 4'fwhenA the stern 6is in' an oblique position and can engage the edges of the opening when the stem is in a central, vertical position. It is not necessary that the support have more than two arms, that all the arms be flexible or shaped identically or symmetrically, that all cam surfaces 13 be inclined away from the periphery, although all of these characteristics are highly advantageous in affording a better centering action and in providing a support having maximum durability and security for a given weight and flexibility. Thus, it is, broadly, sufficient that two diametrically opposed parts of the support or three parts disposed at the apices of a triangle and` suitably distributed about the periphery of the opening have such retaining surfaces, and that one or more of the cam surfaces 13:` beinclined so that the plane geometric figure enclosing the retaining surfaces (a circlein the case illustrated) is reduced when the support is pulled'upwards through the opening. As regards flexibility, it is highly advantageous, although again not essential, that the arms intersect the edge of the opening at an' inclination tothe radius, as shown, so thatthey are readily deflected horizontally by the action of the cam surface. Finally, each arm may provide more thanV one lug for engaging the under side of the deck and/ or more than one retaining surface for resiliently engaging the interior surface of the deck opening. Examples are:

In Figure 5 the stern 6 is attached to a support having two identically shaped arms 10a that are also'thin, -vertically elongated metal strips generally J-shaped in plan. As shown in Figure 8, the upper part of the metal is cut away from the radially outermost part of each arm to leave an abutment or lug' 11a and two retaining edges 12a, 12b, that merge into'v inwardly sloping cam surfacesv 13a, 13b that Iare rounded' with a rad of curvature R'. The diametersY D1, Dz and D3 of thecircumscribed circles are indicated; they havethe'signic'ance previously described for the first embodiment. The hold-down is installed and removed in the same manneras above.

InFigure 6 the construction is as was described for Figures 5 and 8?' but th're'e'armsl 10a of identical construetion are' provided.

In Figure 7 the support has'two identically shaped arms 10b forming loops, thesupportV as a whole being -shaped in plan. Each arm again providesa pair of retaining sur-Y faces and a pairof cam surfaces, differing from Figure 8 only in that'bo'th ends of the strip are attached to the stem 6.

Iclaim as my invention:

1. A hold-down for fastening a bubble cap over an opening in a contacting trayy deck, comprising an upright fastening stem adapted for connection at the top thereof to the bubble cap and a transverse, resilient support.' secured to the bottom of the stern so as to permit downward Vpassage of the support through said opening from above the deck and upward passage therethrough from below yin' the'v undeformed state of the support andy having aV plurality of upwardly directed abutments dlsposed to engage the under side of the deck to limit upward movement of the support, a plurality of lateral retaining surfaceson the resilient support urged resiliently outwards forfrictional engagement with the interior surfaceV of said opening, and cam surfaces above said retaining surfaces on the support merging therewith to move said retaining surfaces resiliently inwards by engagement of said cam surfaceswith said interior surface of the opening, all parts of the support above said retaining suri faces being situated inwardsV with respect tothe retaining surfaces, whereby said support is restrained against downward movement during' assembly and disassembly solely by said resilient, frictional engagement.

2. A hold-down vaccording to claim 1 wherein saidsup'- port comprises a plurality of resilient arms formed of. stripsv that are vertically elongated and laterally flexible, at least two of said-arms bein'gshouldered at their outer ends to provide lugs constituting the said upwardly directed abutments, the end of each said arm immediately above the lug constituting one of said retaining surfaces, the part of each arm above said retaining surface being inclined generally toward the stem to constitute the said cam surface, and the part of each strip adjoining the said cam surface thereon being inclined to the radial plane through said retaining surface thereon.

3. A hold-down according to claim 2 wherein the support consists of four arms grouped about the stem in the form of an H.

4. A hold-down according to claim 2 wherein said arms are rounded at their outer ends and each arm has a pair of spaced retaining surfaces and an intermediate lug.

5. A hold-down according to claim 4 wherein said arms are generally J-shaped.

6. A hold-down according to claim 4 wherein said arms are closed loops having both ends thereof joined to said stem.

7. A hold-down for fastening a bubble cap over a circular opening in .a contacting tray deck, comprising an upright fastening stem adapted for connection at the top thereof to the bubble cap and a transverse support rigidly secured to the bottom of said stem so as to permit downward passage of the support through said opening from above the deck and upward passage therethrough from below in the undeformed state of the support and having a plurality of arms extending out from said stem to beyond the edge of the opening at points distributed about said edge, said arms providing at said points (a) a shoulder disposed for engagement with the underside of the tray to limit upward movement of the support, (b) an upright retaining surface adapted for resilient, frictional engagement with the interior surface of the opening to restrain the support against downward movement during assembly and disassembly, and (c) a cam surface extending upwards from said retaining surface, at least one cam surface being inclined generally toward the stem and at least one of said arms intersecting said edge at an angle to the radius to the point of intersection and being horizontally resilient to reduce the diameter of the circle enclosing said retaining surfaces upon flexure of said arm when said cam surfaces engage the interior surface of said opening during upward movement of the support, all parts of said support above said retaining surface being situated within a circle having a diameter less than that of the circle enclosing said retaining surfaces, whereby said support is restrained against downward movement solely by said resilient frictional engagement.

8. A hold-down according to claim 7 wherein all arms are resilient and intersect the edge of the opening at angles to the radii tothe respective points of intersection and all arms have cam surfaces inclined generally toward the stem.

9. The combination with a contacting tray deck having an opening therein, of a bubble cap situated over said opening and having a part thereof in upwardly supported relation to the deck, and a hold-down therefor comprising a vertical fastening stem aligned with said opening, screw-threaded means securing said bubble cap releasably to the stem against upward movement, and a transverse support within said opening secured to said stem, said support and stem being insertable and removable through said opening from above the tray in the undeformed state of the support and said support including a plurality of arms in engagement at the outer ends thereof with said deck at points spaced along the periphery of said opening and providing at each of said points (a) a shoulder in engagement with the underside of the tray to limit upward movement of the support, (b) a lateral retaining surface in frictional, resilient engagement with the interior surface of said opening to restrain the support against downward movement during assembly and disassembly, and (c) a cam surface extending upwards from said retaining surface, at least one cam surface being inclined generally toward the stem and at least one of said arms being resilient to reduce the size of the closed plane geometric figure enclosing said retaining surfaces upon exure of said one arm when said cam surfaces engage the interior surface of said opening during upward movement of the support, all parts of said support above said retaining surfaces being situated within a closed plane geometric figure smaller than a similar iigure enclosing said retaining surfaces.

Ackroid June 22, 1948 Kelley June 6, 1950

Claims (1)

1. A HOLD-DOWN FOR FASTENING A BUBBLE CAP OVER AN OPENING IN A CONTACTING TRAY DECK, COMPRISING AN UPRIGHT FASTENING STEM ADAPTED FOR CONNECTION AT THE TOP THEREOF TO THE BUBBLE CAP AND A TRANSVERSE, RESILIENT SUPPORT SECURED TO THE BOTTOM OF THE STEM SO AS TO PERMIT DOWNWARD PASSAGE OF THE SUPPORT THROUGH SAID OPENING FROM ABOVE THE DECK AND UPWARD PASSAGE THERETHROUGH FROM BELOW IN THE UNDEFORMED STATE OF THE SUPPORTT AND HAVING A PLURALITY OF UPWARDLY DIRECTED ABUTMENTS DISPOSED TO ENGAGE THE UNDER SIDE OF THE DECK TO LIMIT UPWARD MOVEMENT OF THE SUPPORT, A PLURALITY OF LATERAL RETAINING SURFACES ON THE RESILIENT SUPPORT URGED RESILIENTLY OUTWARDS FOR FRICTIONAL ENGAGEMENT WITH THE INTERIOR SURFACE OF SAID OPENING, AND CAM SURFACES ABOVE SAID RETAINING SURFACES ON THE SSUPPORT MERGING THEREWITH TO MOVE SAID RETAINING SURFACES RESILIENTLY INWARDS BY ENGAGEMENT OF SAID CAM SURFACES WITH SAID INTERIOR SURFACE OF THE OPENING, ALL PARTS OF THE SUPPORT ABOVE SAID RETAINING SURFACES BEING SITUATED INWARDS WITH RESPECT TO THE RETAINING SURFACES, WHEREBY SAID SUPPORT IS RESTRAINED AGAINST DOWNWARD MOVEMENT DRUING ASSEMBLY AND DISASSEMBLY SOLELY BY SAID RESILIENT, FRICTIONAL ENGAGEMENT.

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