US3001488A - Latching mechanism for access door - Google Patents

Description

Sept. 26, 1961 R. GoDsHALK ETAL LATCHING MECHANISM FOR ACCESS DOOR Filed April l5, 1958 2 Sheets-Sheet 1 IN V EN TORS Russell L. Godshalk R beri E. Lowe ATTORNEY SePt- 26, 1961 R. L GoDsHALK ETAL 3,001,488

LATCHING MECHANISM FOR ACCESS DOOR Filed April l5, 1958 2 Sheets-Sheet 2 FIG. 4

56 1 f 72k- Issm :i 72B/` /L f|1 M 44 I INVENToRs Russell L. Godshalk BY Roberr E. Lowe MAM' ATTORNEY LATCG MlECSM EUR ACCESS DOOR Russell L. Godshalk, Akron, hio, and Robert E. Lowe,

Westport, Conn., assignors to The Babcock 8L Wilcox glompany, New York, NY., a corporation of New ersey Filed Apr. 15, 1958, Ser. No. 728,683 6 Claims. (Cl. 11d- 176) This invention relates to an access door assembly particularly adapted for an opening formed in a boundary wall of a furnace or chamber within which high temperature gases at a pressure considerably above atmospheric pressure are generated or flowing.

When a wall opening is provided through which access may be had to a furnace or chamber of the character described lfor `cleaning or observation, it is essential that the opening be iitted with -a door assembly so constructed and arranged as to safeguard the operator from blasting by hot gases when the `door is opened. With the usual door construction for a furnace under pressure, high pressure aspirating air is introduced into the access opening to counter the discharge of hot gases, with the aspirating air supply control valve interlocked with the door latching mechanism to prevent opening of the door until the air control valve is in operating position and with the door completely free to move from its closed to fully open position once the latching mechanism is released. Experience has proven that a definite hazard exists with this door construction under a condition Where the air control valve is turned on preparatory to unlatching the door and aspirating air flow is either inadequate or non-existent for some reason, such as pluggage of the valve, or fails prior to release of the door. Frequently the operator is unaware of the air flow deficiency or failure until the door is opened. Since the latching mechanism on this type of door has to be wholly released before the door can be opened, an incautious operator rapidly swing the door open would be blasted by the hot gases in the absence of mechanical constraint of the door in its outward movement from closed position. Even a cautious operator would be subject to this danger upon the sudden opening of a sticky door after the application of force.

The main object of the present invention is to provide an access door assembly of the character described which is simple to construct and operate, and has components so interlocked as to insure positive protection at all times to the operating personnel despite possible carelessness on their part or sticking of the door to its seat. In accordance with the present invention, the outer end of an opening formed in a boundary wall of a chamber conning high temperature gases under superatmospheric pressure is closed by a door pivotally connected to the wall. Provision is made for directing high pressure aspirating gaseous fluid into the opening in the direction of the chamber to counter the discharge of hot gases when the door is opened for lancing or observation purposes; and for preventing outward movement of the door until the control for high pressure aspirating iluid supply is set in flow position. The door latching mechanism comprises a latch normally interlocked with the door and pivotally connected to the wall for movement into and out of locking relation with the door; and latch adjusting means associated with the latch and cooperating therewith to lock and unlock the door. Provision is made for effecting outward movement of the door, while preventing pivotal movement of the latch and maintaining the latch in interlocking relation with the door until the door is at least partially opened. This arrangement provides positive constraint of the door in its outward ddlASS Patented Sept. 26, 1961 movement from closed position until the operator is assured that the aspirating air supply system is functioning properly and to the extent that the operator will be apprised of and protected `from gas blasting in the event that the aspirating air supply is deficient or non-existent.

rThe various features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a specific embodiment of our invention.

Of the drawings:

FIG. 1 is a front elevation of an access door assembly constructed in accordance with our invention;

FIG. 2 is a plan section taken along the line 2-2 of FIG. l;

FIG. 3 is a sectional elevation taken along the line 3-3 of FIG. l;

FIG. 4 is an enlarged fragmentary plan section showing the door latching mechanism;

FIG. 5 is a vertical section taken along the line 5-5 of FIG. 4; and

FIG. 6 is a vertical section taken along the line 6--6 of FIG. 4.

In the embodiment of the invention shown in the drawings the door assembly is associated with a wall 10 including vertically extending fluid cooled tubes l2, having an opening 14 therein, and providing a boundary for a chamber or furnace 16 within which high temperature generated or flowing. The opening 14 is formed in known manner by displacing intermediate portions of adjoining pairs of some of the tubes 12 laterally or outgases at a pressure well above atmospheric pressure are wardly. The wall lil includes inner metal casing 18 suitably secured to the tubes l2, insulation 20 and outer metal casing 22; and cooperates with other walls of similar construction to provide a sealed chamber permitting operation at high positive gas pressures.

An inner frame 24 is symmetrically arranged in the opening 14 and forms a passage 26 of circular crosssection opening to the chamber 16 at its inner end. The inner frame 24 comprises a cylindrical sleeve section 28 and a frusto-conical section 3d disposed coaxially of the sleeve 28 and having an apex angle of about 70. The sleeve 28 is secured by welding to an outer frame 32 disposed adjacent the perimeter of the opening 14 and surrounding most of the inner frame 24; .is beveled at its inner end; and is formed with an annular lip 28A at its outer end extending radially inward. The frusto-conical section 30 has its inner end disposed within and in sealing relation with the lip 28A, diverges outwardly from the sleeve 28, and is secured at its outer end by welding to the outer frame 32.

In order to prevent escape of hot gases when the access opening 14 is uncovered for lancing or observation of the chamber 16, provision is made for directing jets of high pressure, high velocity gaseous fluid, such as air or steam, into the passage 26 in the direction of the chamber 16. For this purpose, the outer frame 32 cooperates with the inner frame 24 to define an air manifold 34. Circumferentially spaced, angularly directed holes 36 are drilled in the lip 28A for the discharge of jets of air into the passage 26 in converging relation with the axis thereof and preferably at an angle of about 6 relative to the axis. Compressed air or other gaseous fluid relatively high pressure is delivered to the manifold 34 through pipes 38, 39 and 40, the supply of fluid being controlled by a three-way valve 42. The pipes 39 and 40 are connected by a T-titting 4.1 into which is threaded a cap screw 43 for adjustment of the aspirating air supply to the passage 26.

The outer end of the outer vframe 32 is formed with a rectangular lateral extension or flange 44 suitably secured to and overlapping the outer casing 22. A circular door 46 formed at one side with a pair of vertically spaced laterally extending a1ms 43 is pivotally connected toa pair of vertically spaced and aligned lugs Sil on the outer face of the ilange 44 by eccentric pivot pins S2 engaging the arms 48 and the lugs 50. Thus the door is hinged for movement about a Vertical axis parallel to the wall 10. T-he opposite side of the door is formed with an extension 54 projecting outwardly and then laterally yand having a U-shaped groove 56 formed in the outer end thereof. A groove 58 is formed in the inner face of the door 46 and illed with asbestos or other suitable packing material 66) to provide a gas-tight seal between the door and the ange 44 when the door is closed. The pivot pins 52 are eccentrically formed so that they can be adjusted to obtain maxim-um sealing contact between the llange 44 and the packing 60.

In accordance with the invention and as clearly illustrated in FIGS. 3-6, the door latching mechanism comprises latch guide means which includes a pair of vertically spaced and aligned lugs 62 secured to the flange 44 and each formed with an outwardly and horizontally projecting beveled stop 65. An externally threaded latch or eye bolt 66 of a diameter less than the spacing between the lugs 62 is interlocked with the door 46 in the groove 56 thereof and is pivotally connected between the lugs 62 by a pin 68 for movement into and out of locking relation with the door about a vertical axis substantially parallel to the wall l0. The outer end of the door extension 54 is disposed opposite the outer ends of the stops 64 in outwardly spaced relation thereto when the door is in its closed position. A hand knob 76 inclurlin-g an internally threaded tubular sleeve 72\ is threadably secured to the latch 66 and cooperates therewith to lock and unlock the door 46. The sleeve 72 includes an intermediate portion 72A of reduced diameter adapted to interlock with the door 46 in the groove 56 thereof; an outer portion '72B of an outside diameter greater than the distance between the legs of the groove 56 and arranged to engage the outer face of the door opposite the groove 56 when the door is in its closed position; and an inner portion 72C of an outside diameter greater than the spacing between either the legs of the gnoove 56 or the stops 64, inwardly and horizontally spaced yfrom the inner `face of the door opposite the groove 56 when the door is closed, and disposed alongside the beveled portion of the stops 64 in interlocking relation therewith when the door is in its closed position. The inner portion 72C of the sleeve 72 cooperates with the stops. 64 (to prevent pivotal movement of the latch 66 out of locking relation with the door and to maintain the latch 66 in locking relation with the door until the door is at least partially opened.

Movement of valve 42 is manually eiected by a pivotally mounted wrench 74 disposed outwardly of and interlocked with the knob 70 to prevent opening of the door 46 until after the wrench 74 is rotated 90 clock-wise. After the wrench 74 is so rotated and assuming that the aspirating air supply system is functioning properly, air discharges into the passage 26 by way of the pipes 38, 39 and 40 at a pressure suliicient to at least neutralize the pressure of the gases in the chamber i6, thereby preventing the discharge of hot gases through the passage Z6 and permitting lancing or other operations with safety when the door is opened.

When the door is fully closed, as shown in the drawings, the valve 42 is in position to allow low-pressure cooling air to ow from a pipe 76 to the passage 26 by way of the pipes 39, 49 and the `door 46 is sealed against the flange 44 throughout the perimeter of the packing 60 through the force of the sleeve portion 72 of the knob 70 engaging the latch 66 and bearing against the outer face of the lateral extension 54 of the door. When the door is to be opened, the wrench 74 is rotated to permit iow of high pressure air into the passage 26 and the knob 70 is turned counterclockwise to el'I'ect outward movement of the sleeve 72. As the knob is turned counter-clockwise, the outer portion 72B of the sleeve 72 `disengages from the outer face of the lateral extension 54 of the door; then the inner portion 72C of the sleeve 72 engages the inner face of the lateral extension 54 to effect cutwand movement of the door from its closed position; and then the inner portion 72C of the sleeve moves beyond the stops 64, thereby permitting pivotal movement of the latch 66 out of the door groove 56. Once the latch 66 is pivotally moved out of locking relation with the door, the Kdoor is completely free to swing outwardly. The lateral extension 54 is provided with `an upright handle 78 to facilitate movement of the door. Thus the inner portion 72C of the sleeve 72 and the stops 64 cooperate to prevent pivotal movement of the latch 66 and to maintain the latch 66 in interlocking relation with the door until the inner portion 72C of the sleeve moves beyond the stops 64, while the door is positively constrained in its outward movement from the ilange 44 until the latch is pivotally moved out of locking relation therewith. In the event that the aspirating air supply to the passage 26 is deficient or non-existent for some reason, such as pluggage of the valve 42 or pluggage of the holes 36 With ash or other foreign matter, the operator will become aware of this fact by the discharge of gases as soon as the door moves outwardly from the flange 44.

The positive constraint of the door in its initial movement from the ilange 44 and the protection afforded by the door when ythe unsafe condition becomes apparent, safeguard the operator from injury and permit immediate closing of the door to correct the condition.

While in accordance with the provisions of the statutes we have illustrated and ldescribed herein the best form of the invention now known to us, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed Without departing from the spirit of the invention covered by our claims, and that certain 'features of our invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

l. In combination with a wall having an opening therein and providing a boundary for a chamber conning high temperature gases under superatmospheric pressure, a door pivotally connected to said wall and normally closing the outer end of said opening, means for introducing a gaseous fluid under pressure into said opening in the direction of said chamber, and door latching means comprising latch guide means including ya stop secured to said wall, a latch normally interlocked with said door and pivotally connected to said latch guide means for movement into and out or locking relation with said door, and latch adjusting means associated with said latch and cooperating therewith to lock and unlock said door, said latch adjusting means coacting with said latch to eiect outward movement of said door, while cooperating with said stop of said latch guide means to prevent pivotal movement of said latch until the door is at least partially opened and maintain said latch in interlocking relation with door until the door is at least partially opened.

2. In combination with a wall providing a boundary for a chamber confining high temperature gases under superatmospheric pressure, means including a door frame in said wall `forming a passage extending through said wall and opening at its inner end to said chamber, a door pivotally connected at one side to said iframe and normally closing the outer end of said passage, means for introducing a gaseous lluid under pressure into said passage in the direction of said chamber, and door latching means comprising latch guide means including a stop secured to said frame, a latch normally interlocked with said door at the opposite side thereof and pivotally connected to said latch guide means for movement into and out of locking relation with said door, and latch adjusting means `associated with said latch and cooperating therewith to lock and unlock said door, said latch adjusting means coacting with said latch to eiect outward movement of said door, while cooperating with said stop of said latch guide means to prevent pivotal movement of said latch until the door is at least partially opened and maintain said latch in interlocking relation with said door until the door is at least partially opened.

3. In combination with a wall having an opening therein and providing a boundary for a chamber coniining high temperature gases under superatmospheric pressure, a door pivotally connected at one side to said wall and normally closing the outer end ot said opening, means including a valve controlled conduit for introducing a gaseous fluid under pressure into said opening inthe direction of said chamber, means for preventing opening of said door until the valve of said conduit is opened, and door latching means comprising latch guide means including a stop secured to said wall, a latch normally interlocked with said door at the opposite side thereof and pivotally connected to said latch guide means for movement into and out of locking relation with said door, and latch adjusting means associated with said latch and cooperating therewith to lock and unlock said door, said latch adjusting means coacting with said latch to effect outward movement of said door, while cooperating with Said stop of said latch guide means to prevent pivotal movement of said latch until the door is at least partially opened and maintain said latch in interlocking relation with said door until the door is at least partially opened.

4. In combination with a wall providing a boundary for a chamber confining high temperature gases under superatmospheric pressure, means including a door frame in said wall forming a passage extending through said Wall and opening at its inner end to said chamber, a door pivotally connected at one side to said frame and normally closing the outer end of said passage, means including a valve controlled conduit -for introducing a gaseous uid under pressure into said passage in the direction of said chamber, means for preventing opening of said door until the valve of said conduit is opened, and door latching means comprising latch guide means secured to said frame and including a lug formed with an outwardly projecting stop, a latch normally interlocked with said door at the opposite side thereof and pivotally connected to said latch guide means for movement into and out of locking relation with said door, and latch adjusting means including a sleeve normally interlocked with said door and threadably engaging said latch and cooperating therewith to lock and unlock said door, said sleeve having a portion normally engaging the outer face of said door when the door is in its closed position and another portion arranged to engage the inner face of said door and effect outward movement of the door as the sleeve is disengaged from said latch, said other portion of said sleeve being normally interlocked with said stop and cooperating therewith to prevent pivotal movement of said latch out of locking relation with said door until the door is at least partially opened and to maintain said latch in locking relation with said door until the door is lat least partially opened.

5. ln combination with a wall providing a boundary for a chamber conning high temperature gases under superatmospheric pressure, means including a door frame in said wall forming a passage extending through said wall and opening at its inner end to said chamber, a door pivotally connected at one side to said trame for movement about an axis substantially parallel to said wall and normally closing the outer end of said passage, said door having a groove at the opposite side thereof, means including `a valve controlled conduit for introducing air into said passage inthe direction of said chamber at a pressure sucient to at least neutralize the chamber pressure when the door is to be opened, means for preventing opening of said door until the valve of said conduit is opened, and door latching means comprising latch guide means secured to said frame and including a pair of lugs each formed with an outwardly projecting stop, a latch normally interlocked with said door in the groove thereof and pivotally connected to said latch guide means for movement into and out of locking relation with said door about an axis substantially parallel to said Wall, and latch adjusting means including a sleeve normally interlocked lwith said door in the groove thereof and threadably engaging said latch and cooperating therewith to lock :and unlock said door, said sleeve having a portion normally engaging the outer face of said door when the door is in its closed position and another portion arranged to engage the inner face of said door and effect outward movement of the door as the sleeve is disengaged from said latch, said other portion of said sleeve being normally interlocked with said stops and cooperating therewith to prevent pivotal movement of said latch out of locking relation with said door until the door is at least partially opened and to maintain said latch in locking relation with said door until the door is at least partially opened.

6. In combination with a Wall providing a boundary for a chamber confining high temperature gases under superatmospheric pressure, means including a door frame iu said wall forming a passage extending through said wall and opening at its inner end to said chamber, a door pivotally connected at one side to said frame for movement about a vertical axis substantially parallel to said wall and normally closing the outer end of said passage, said door being formed with an extension at the opposite side thereof having a groove, means including a valve controlled conduit for introducing lair into said passage in the direction of said chamber at a pressure sufficient to at least neutralize the chamber pressure when the door is to be opened, means for preventing opening of said door until the valve of said conduit is opened, and door latching means comprising latch guide means secured to said frame and including a pair of lugs each formed with an outwardly projecting stop, a latch normally interlocked with said door in the groove thereof and pivotally connected to said latch guide means for movement into and out of locking relation with said door about a vertical axis substantially parallel to said wall, and latch adjusting means including a sleeve normally interlocked with said door in the groove thereof `and threadably engaging said latch and cooperating therewith to lock and unlock said door, said sleeve having a portion normally engaging the outer face of said door when the door is in its closed position and another portion arranged to engage the inner face of said door and effect outward movement of the door as the sleeve is disengaged fromy said latch, said other portion of said sleeve being normally interlocked with said stops and cooperating therewith to prevent pivotal movement of said latch out of locking relation with said door until the door is at least partially opened and to maintain said latch in locking relation with said door until the door is at least partially opened.

References Cited in the le of this patent UNITED STATES PATENTS 781,371 Sherman Jan. 31, 1905 1,583,396 Demuth May 4, 1926 1,769,979 Whittam July 8, 1930 2,393,078 Wager Jan. 15, 1946 2,758,554 Ohman Aug. 14, 1956 FOREIGN PATENTS 652,009 Germany Oct. 23, 1937 6,1577 Great Britain 1889

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