US2881943A - Access door for pressure vessels - Google Patents

Description

April 14, 1959 D. D. BOATRIGHT ETAL 2,881,943

ACCESS DOOR FOR PRESSURE VESSELS 2 Sheets-Sheet 1 Filed Jan. 29, 1958 INVENTORS. BOATRI GHT 8 DEAN D. I JOHN P. HOLT Maw V ATTORNEYS D D. BOATRIGHT ET AL 2,881,943

ACCESS DOOR FOR PRESSURE VESSEL-S A ril 14, 1959 'Filed Jan. 29, 1958 2 Sheet-Sheet 2 A WM W 2a; 1 a v I v V. /H "VI PR4 3 UP 9 N ll 5 3: l h 9 .1

INVENTQRS. DEAN o. BOATRIGHT &- JOHN P. HOLT ATTORNEYS United States Patent ACCESS DOOR FOR PRESSURE VESSELS Dean D. Boatright, Cleveland, and John P. Holt, Beachwood, Ohio, assignors, by mesne assignments, to Central National Bank of Cleveland, trustee, Cleveland, Ohio, a national banking association Application January 29, 1958, Serial No. 711,844

' 4 Claims. (Cl. 220-57) The present invention relates to an access door for a pressure vessel and, more particularly, to a closure having improved safety features for an opening in tanks and the like designed to withstand considerable internal pressures.

In various industrial applications, it is often necessary or desirable to confine solids and/or fluids within suitable containers at superatmospheric pressures. For example, in one instance, ground refractory material such as cementitious material, various aggregate mixtures, and the like are maintained in tanks or other suitable containers at elevated pressures. This pressure is then used to discharge the material from the tank through a nozzle and along a wall of a furnace to replace or repair the linings thereof. A tank or vessel of the type described for holding material under pressure is disclosed in U.S. Patent No. 2,615,693 to Matirko.

From the foregoing, it will be apparent that a door or like closure member for a pressure vessel must itself be able to withstand the pressures employed and desirably have safety means to prevent or guard against accidental and explosive openings of the door with possible attendant injuries to operating personnel.

The present invention provides an access door or closure for a pressure vessel and embodies improved safety features. These features are either automatically in place when the door is closed or must be put in proper place before the door can be tightened in a closed position to permit high pressures and temperatures to be established within a pressure vessel.

In our access door, a door member is carried by a beam or beams which are pivotally secured to a pressure vessel. Safety catches carried by the vessel directly engage the end portions of the beams, and latch means overlies the beam or beams to urge them and the door toward the pressure vessel. Preferably, the latch means engages 'a recess in the beams, so that the door may lift slightly to bleed ofl pressure from within the tank gradually, and yet the latch means still acts in this position as a positive restraint to prevent complete withdrawal or opening of the door. Preferably also, at least one of the safety catches prevents proper seating of the latch means until the safety catch is itself properly seated and the door is in readiness to be clamped in a closed position. In addition, the beams which carry the door may have seats for the safety catches which slant inwardly of the beams further to insure a strong and tight sealing of the door assembly with respect to a pressure vessel.

It is, therefore, a principal object of the present invention to provide an improved access door or closure for a pressure vessel.

Another object is to provide such a door having safety means to prevent accidental and explosive openings of the door.

A further object is to provide such a door having safety means which are either automatically in place when the door is closed or must be put in place before it is possible to clamp the door in a closed position.

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A still further object is to provide such a door which closes well even though all of the parts of the door assembly do not run in perfect alignment.

Other objects will become apparent as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention consists of the features hereinafter fully described and particularly pointed out in the claims, the annexed drawing and following disclosure describing in detail the invention, such drawing and disclosure illustrating, however, but one or more of the various ways in which the invention may be practiced.

In said annexed drawing:

Figure 1 is a side view of a pressure Vessel embodying the present access door.

Figure 2 is an enlarged fragmentary view of Figure 1 along the plane of the line 2-2.

Figure 3 is an enlarged fragmentary section of Figure l on the line 33.

Figure 4 is a plan view of Figure 3, and

Figure 5 is a right-hand end view of Figure 4.

Referring to the drawing, the embodiment shown includes a container or pressure vessel 10, usually made from steel plate, supported on a wheeled carriage or wagon 11 by which the pressure vessel 10 is transported from station to station. Suitable valves and other controls (not shown) are located on the carriage 11 to effect the operation of the container 10 during which pulverulent or ground material is discharged by means of superatmospheric pressure within the container 10 through an outlet pipe 12, flexible pressure hose 13, and discharge nozzle 14, in a manner disclosed by the cited Patent No. 2,615,693 to Matirko.

The access door of the present invention is indicated in Figure 1 by the reference numeral 15 and includes a cover plate or door member 16 having an annular gasket 17 which tightly engages the rim of a collar 18 set in the wall of the vessel 10, thereby defining an opening. The collar 18 is preferably welded to the pressure vessel 10, and the various parts of the present access door assembly, hereinafter described are similarly secured together unless otherwise indicated to withstand the pressures involved.

A pair of generally parallel beams or pressure bars 19 and 20 are pivotally secured at a medial portion of the bars by a pin 21 to upstanding lugs 22 and 23, respectively, which are fixed to the plate or door 16 and straddle the bars, as indicated. It is possible to construct the access door of the present invention using only one of such beams 19 or 20, but two beams are preferred since each may then be designed with sufficient strength to hold the door in a closed position under the contemplated working conditions of the pressure vessel should the remaining beam or pressure bar fail. Each beam or pressure bar has an ear portion 24 at corresponding ends which is hingedly secured to upstanding lugs or webs 25 and 26 by a pin 27. The free ends of the beams 19 and 20 have a recessed area indicated at 23 which may be slightly concave. Also, the bars 19 and 20 are each formed with seats 29 and 30 which are placed on opposite sides of the point of attachment of the bars to the lugs 22 and 23 and slant or tilt in that direction.

A safety catch is provided directly to engage each of the corresponding end portions of the beams or bars 19 and 20. Such a safety catch may conveniently comprise a bolt or shank 31 having an eyelet portion 31a at one end to receive a pin 32. The pin 32 secures the bolt 31 to the upstanding lugs 25 (Figure 4) carried by the pressure vessel. Each bolt 31 terminates at its other end in a flat head 33 which is parallel to and jointly cont-acts the corresponding seats 29 and 30 of the generally parallel bars 19 and 20 when the bolts 31 are swung to a closed position,

8 as shown in Figures 2 through 4. In addition, the safety bolt adapted to overlie the free ends of the hinged bars 19 and (the right-hand bolt as viewed in Figure 3) has a projection 34 which extends toward but terminates short of the seat 28 on the bars 19 and 20 which is adapted to receive suitable latch or lugging means.

The latch means may be any of those normally used for such purposes, such as a cam-operated lever or a threaded type of lock or latch. In the embodiment illustrated, the last mentioned type is shown wherein a threaded shank or bolt 35 has an eyelet end portion 35a. A pin 36 pivotally secures the latter to the lugs or ribs attached to the pressure vessel 10. A cross-bar 37 has an oversized opening to pass the shank 35 and is provided with a convex underside to conform with the concave seats 28 in the bars 19 and 20. A wing nut 38 engages the threaded end of the shank 35 and forces the cross-bar 37 to bear on the bars 19 and 20 in the seat 28.

In practice, assuming the access door to be initially open, the beams 19 and 20 are swung about the pin 27 to place the cover plate 16 over the collar 18. It will be noted that the beams 19 and 20 extend from their hinged ends across the plate 16 to the latching mechanism. One purpose of this arrangement is to enable the cover plate or door to swing through a suitable arc, so that a tight closing can be achieved even though not all of the parts are in exact alignment. The door 16 seats accurately because it is hung loosely from the beams 19 and 20 by means of the pin 21 and lugs 22 and 23. In closing the door, the left-hand bolt 31, as viewed in Figures 2 and 3, automatically positions itself so that it is an effective safety device should the pin 27 or beams 19 and 21 fail. The right-hand bolt 31 is now swung into place and must be positioned on its seat across the beams before the latch bolt can be itself positioned for tightening the door in a closed position. This results because the projection 34 does not permit the proper positioning of the latch bolt 35 until the bolt 31 associated with the projection 34 is in place. On the latch side of the door 16 as on the hinge side, pin 36 and the lugs or webs 25 and 26 together with appropriate sections of the beams or bars 19 and 20 are all of suflicient size and strength so that if some parts of the assembly fail, those remaining are strong enough to hold the door closed. Further, the sizes of the various members of the door are so proportioned that should any part fail, the pressure within the vessel is relieved comparatively slowly in a safe manner so that the door may ultimately be opened without danger of its being thrown open violently. With the right-hand bolt 31 in proper position, the latch bolt 35 is swung over the bars 19 and 20 and the wing nut 38 tightened to complete the lugging of the door assembly over the collar 18.

Vhen it is desired to open the access door, Wing nut 38 is loosened to allow the beams 19 and 20 to rise slightly and thereby lift the cover 16 somewhat away from the collar 18. This provides a vent to relieve the pressure within the vessel 10 from beneath the lips 16a of the door in a safe manner. Because of the recess 28 in the beams the latch bolt 35 is not forced free of the ends of the beams. Instead the bolt 35 catches at the side of the recess 28 to act as a positive restraint to a further rise in the cover plate 16. To permit this slight rise of the door, there is preferably some freedom of movement or play between the flat heads 33 of the safety catches and the seats 29 and 30 on the beams as indicated in Figures 2 and 3. After sufiicient pressure has been relieved, the door 16 may be pushed back against the collar 18 or allowed to fall back by its own weight, and the latching bolt 35 then pivoted about the pin 36. The righthand bolt 31 is then similarly pivoted out of the Way of the bars 19 and 20 and door 16 lifted about the hinge pin 27. During this time, the left-hand bolt 31 automatically moves away from its seat 29 in the beams and about the pin 32.

It will now be apparent that we have provided an improved access door for a pressure vessel and particularly one having safety means to prevent accidental and explosive opening of the door. The safety means of our door are either automatically in place when the door is closed or must be put in place to enable the door to be locked in position. Our access door closes well even though all of the parts are not in perfect alignment. The door opens from the outside of the vessel, leaving nothing in the opening to interfere with free access to the interior of the pressure vessel. The door is easily and quickly opened or closed and is held in a closed position by only one fastening. The major parts of the doors hinges and latches or supporting beams may be severely damaged or destroyed and the door will still not fly open.

Other forms embodying the features of the invention may be employed, change being made as regards the features herein disclosed, provided those stated by any of the following claims or the equivalent of such features be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A closure assembly for a pressure vessel and the like including a door member, a bar member secured to the door member adjacent a medial portion of the bar member and pivotally mounted on the pressure vessel adjacent an end of the bar member, safety catches pivotally carried by the pressure vessel and adapted to overlie and engage each end portion of the bar member, and latch means pivotally mounted on the pressure vessel and adapted to bear against the bar member adjacent its free end and urge said bar member toward the pressure vessel.

2. A closure assembly for a pressure vessel and the like including a door, a pair of substantially parallel bars, said bars being secured to the door adjacent a medial portion of the bars and pivotally mounted on the pressure vessel adjacent corresponding ends of the bars, safety catches pivotally carried by the pressure vessel and adapted to seat upon the adjacent end portions of the substantially parallel bars, and latch means pivotally mounted on the pressure vessel and adapted to bear jointly on the bars adjacent their free ends to urge the bars against the pressure vessel.

3. An access door for a pressure vessel and the like including a plate member to engage and close an opening in the pressure vessel, a pair of substantially parallel pressure bars, said bars being pivotally secured to theplate member adjacent a medial portion of the bars and pivotally mounted on the pressure vessel adjacent corresponding ends of the bars, safety bolts pivotally carried by the pressure vessel and adapted to seat upon the adjacent end portions of the pressure bars, latch means pivotally mounted on the pressure vessel and adapted to seat jointly on the bars adjacent their free ends to urge the bars toward the pressure vessel, and a projection on the safety bolt adapted to seat upon the adjacent free ends of the pressure bars which extends toward and terminates short of said seat of the latch means on said bars to prevent positioning of said latch means until said last mentioned safety bolt is properly placed.

4. An access door for a pressure vessel and the like including a plate member to engage and close an opening in the pressure vessel, a pair of substantially parallel pressure bars, said bars being pivotally secured to the plate member adjacent a medial portion of the bars and hingedly mounted on the pressure vessel adjacent corresponding ends of the bars, said bars having seats on opposite sides of said medial portion slanting toward said medial portion, safety bolts pivotally mounted on the pressure vessel and adapted to swing over the opposite ends of the bars and engage said seats on the bars, and latch means pivotally mounted on the pressure vessel References Cited in the file of this patent UNITED STATES PATENTS Tinney Feb. 23, 1897 6 Pagano Feb. 6, 1934 Hill June 26, 1938 Williamson et a1 June 12, 1951 FOREIGN PATENTS Germany Sept. 13, 1893

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