US3731837A

US3731837A - Cover plate

Info

Publication number: US3731837A
Application number: US00157111A
Authority: US
Inventors: D Platts; K Hunter
Original assignee: General Descaling Co Ltd
Current assignee: General Descaling Co Ltd
Priority date: 1970-12-11
Filing date: 1971-06-28
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08
Also published as: GB1361397A; FR2117632A5; IT945380B; CA952830A; DE2134934B2; DE2134934A1; DE2134934C3

Abstract

A container for transport or storage of liquid in bulk having a filling opening defined by an upstanding neck, the combination of a cover plate having a depending flange, by which the cover plate, when in position, is located on said neck, interlocking means for positively securing the cover plate to the neck including annular seating surfaces formed respectively on the neck and flange of the cover plate, a plurality of circumferentially arranged balls for operative engagement with said seating surfaces and by which the cover plate is positively held in position thereon, an annular cage encircling the neck and by means of which the balls are normally held in their operative position, the cage being capable of displacement by which the balls can be withdrawn from their operative position to a release position to permit removal of the cover plate.

Description

United States Patent 1 Platts et al.

[54] COVER PLATE [75] Inventors: Douglas John Platts, Worksop; Keith Ellis Hunter, Sheffield, both ailin laaq.

[73] Assignee: General Descaling Company, Limited, Nottinghamshire, England 22 Filed: June28, 1971 21 Appl.No.: 157,111

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 11/1965 Sorensen ..220/55 R X 3/1936 Parker ..220/55 R X 1 May8,1973

Gordon ..220/55 R X Drucker ..220/55 A X [57] ABSTRACT A container for transport or storage of liquid in bulk having a filling opening defined by an upstanding neck, the combination of a cover plate having a depending flange, by which the cover plate, when in position, is' located on said neck, interlocking means for positively securing the cover plate to the neck in cluding annular seating surfaces formed respectively on the neck and flange of the cover plate, a plurality of circumferentially arranged balls for operative engagement with said seating surfaces and by which the cover plate is positively held in position thereon, an annular cage encircling the neck and by means of which the balls are normally held in their operative position, the cage being capable of displacement by which the balls can be withdrawn from their operative position to a release position to permit removal of the cover plate.

Patented May 8, 1973 3,731,837

4 Sheets-Sheet l Patented May 8, 1973 4 Sheets-Sheet 2 Patented May 8, 1973 I 3,731,337

4 Sheets-Sheet 5 COVER PLATE or lid for the filling opening of the container or tank of the vehicle.

Most large capacity vehicles of this kind, whether it be a road vehicle or a rail wagon, are equipped with power actuated braking systems. Both on starting and stopping a vehicle the resultant surge of liquid will cause an appreciable rise in pressure within the container, and in bringing it to a halt, especially should it be necessary to apply the brakes suddenly as in an emergency, the increase in pressure may prove highly dangerous unless the cover plate is securely held in position and sealed. Therefore, it becomes all the more important that cover plates are not only fluid tight to prevent any escape of liquid or gas vapor therefrom in the case of petroleum and other volatile compounds, but shall be capable of withstanding high pressure without shifting.

According to the present invention, in a cover plate or the like having a flange adapted to overlie the neck of a container opening and in which a sealing ring is placed in position between the flange and neck, there is provided interlocking means therefor comprising circumferentially located balls for engagement when in the locked or closed position of the cover plate with angularly inclined seating faces formed respectively on the said neck and flange portions, the balls being retained in a cage by means of which they can be withdrawn from the locked or closed position to a release position within an annular recess or recesses in the said fiange.

The arrangement has the advantage that any increase in pressure within the container tending to unseat the cover plate is transferred through the balls to the seating on the neck of the container opening. In practice the seating faces may be machined at an angle of 45, the seating on the neck of the container being formed as an undercut shoulder thereon and the seating on the flange of the cover plate being extended to form an entrant wall to the recess into which the balls can be withdrawn.

The invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a sectional view of a cover plate;

FIG. 2 is a detailed plan view;

FIG. 3 is a transverse section of a cover plate constructed in accordance with the invention but having means by which it is supported for lateral swinging movements when released;

FIGS. 4 and 5 are detail sectional views showing cam operated means for effecting displacement of the ball cage when releasing the cover plate, and

FIG. 6 is a part sectional view showing a cover plate having an internal sealing plate.

Referring to FIG. 1, 1 indicates the shell of a container or a cylindrical tank and 2 the neck or throat of a filling opening, 3 being part of a domed cover plate or lid.

The cover plate in accordance with this invention is retained in its closed position by a number of balls 4 mounted in openings in a caged formed as a carrier ring 5, the ring 5 having laterally projecting brackets 5' which, as shown in FIG. 2, are constructed in the form of a handle by means of which the cover plate as a whole can be raised prior to being lifted off the neck when it is to be removed.

To facilitate lift off a similar bracket or handle 3 is provided on the cover plate or lid 3 so that the operator can apply pressure to the handle 5' by gripping both handles.

It will be seen that the cover plate 3 has a depending flange 7 and that both the flange 7 and an external shoulder 8 on the neck are formed with seating faces 10 and 11, with which the balls 4 interlock. The seating faces 10 and 11 are similarly at an: angle (conveniently 45) to the vertical, being parallel or substantially parallel to one another and therefore any upward lift, i.e. thrust, to which the cover plate 3 may be subjected due to a rise of pressure in the tank or container 1 will be transmitted from the seating face 10 through the balls 4 to the seating face 11 on the neck 2, thereby preventing it from movement, so that the balls and their associated flanges function as inter-locking means.

When it is desired to release the cover plate the cage 5 is raised, when the balls 4 will be forced outwardly until they are fully withdrawn into an annular recess 12 in the flange 7, the side wall of the recess being an extension of the seating 10.

To raise the cage 5 carrying the balls 4 the fingers are placed below the handle 5 at the: same time gripping the handle 3 on the lid 3 so as to apply pressure to force the ball cage upwardly.

The cover plate 3 is effectively sealed to the neck by a neoprene sealing ring 13of L-section, the cover plate being undercut so as to provide a flat 14 on which the ring 13 is located, the horizontal limb 15 of the ring projecting inwardly so as to overlie and make seal with the flat provided by the upper side of the shoulder 8.

To limit the downward movement of the cover plate, stops in the form of lugs 17, either on the cover plate as shown or spaced circumferentially around the neck 2, may be provided.

It will be seen that sufficient clearance is provided between the flange 7 and the neck 2 to accommodate the carrier ring 5 and that its upper end engages beneath the tongue or limb 15 of sealing ring 13 so that on pulling the ring upwardly by means of its handles, the ring will break the seal at the same time as forcing the balls 4 into the recess 12, when the cover plate can be removed.

In large size tankers the weight of the cover plate is considerable and may require several men to remove it. To assist in'its removal the cover plate may be spring assisted in an upwards direction. Furthermore, instead of removing it completely, provision may be made for swinging it clear of the opening and in one such 'arrangement the cover plate is slidably mounted on

vertical pins

20, 21, as shown in FIG. 3. By making the one pin 20 longer than the other when the cover plate has been lifted to a position where it is clear of the shorter pin it can be swung through about the long pin to expose the opening. This arrangement has the advantage that the cover plate remains captive at all times. Sockets 22 are attached to the inside of the neck to receive the

pins

20, 21, the socket for the longer pin housing a compression spring 23.

In the arrangement shown in FIG. 1, when the ball cage or ring 5 is raised it dislodges the sea] at the same time as unlocking the balls and by so doing it introduces a safety factor, inherent in the design, in that should the internal pressure appreciably exceed the external (atmospheric) pressure, the upward thrust on the cover plate is transmitted via surface 10 through the balls to shoulder 11 so that any pull on the cage by the operator will be resisted. Thus the cage cannot be lifted to unlock when a dangerous pressure exists in the vessel.

Provision may be made for releasing any excess pressure before removing the cover plate, i.e. venting before unlocking. This may be done by making the cage holes in the form of vertical slots as shown in FIG. 3. In this way the cage may be given a small vertical movement without lifting the balls, this movement being sufficient to unseat the seal, thus blowing down may then continue in safety. The slot is so proportioned that the condition as in FIG. 1 is retained above the balls so that cover pressure equates to ball locking as before.

It could occur that a slight carriage i.e. cage 5 lift for this arrangement would require more lifting effort than available from simple handles and some form of elementary jacking between parts 1 and 5 could be provided. For example, a pair of simple scroll cams could be mounted on parts 1 and 2 beneath the cage. They would take no part in normal operation but if the cover could not be unlocked because of initial pressure (the desirable feature of the design) the ball cage could be cammed upwards a controlled amount to permit blow down without risk of release. The cams or equivalent mechanical advantage lift the cage sufficiently for the balls to be lifted into the right position. Further lifting by hand would release the closure in the normal way.

One arrangement embodying a lift cam is shown in FIGS. 4 and 5 in which provision is made for raising the ball cage 5 by means of a cam mechanism. As shown a spindle 30 is rotatably mounted in a bearing housing lug 31 attached to the container wall. Fast on one end of the spindle 30 is a cam element 32, the face of which underlies the horizontal limb 25 of the cage. On the outer end of the spindle 30 is a squared boss 33 to receive a turn buckle or lever 34 by which the cam 32 can be turned from the closed position shown in FIG. 4 to the open position shown in FIG. 5, in which the ball cage 5 has been raised to force the balls 4 into the recess 12. In practice the mechanism is duplicated on opposite sides of the neck opening. Clearly the amount of lift of the cage can be controlled merely by turning the lever 34 through a greater or smaller angle to suit operating conditions.

Referring now to FIG. 6 of the drawings, the cover plate 3 has attached to its underside a dish-shaped sealing disc 27 having a shouldered edge 28 which when the cover plate is in position makes sealing contact with the upper edge of the neck 2. Disc 27 is secured to the plate 3 by a threaded stud on the underside of the plate and a fixing nut 29. By fitting a sealing disc 27 on the underside of the main cover plate 3 it has the advantage of providing a trapped volume of vapor between itself and the cover plate and thus of providing a ready and convenient means for the operator of testing the integrity of the outer seal.

In a particular use, the inner space between the cover plate and disc is maintained at a small pressure. The existence of such pressure is a positive guarantee to the operator that moisture and contaminants have not and cannot enter the interior chamber of the container beneath the sealing disc. In this particular case the interior chamber itself, although sealed, would not be pressurized.

While the embodiment is intended primarily for transport vehicles and has been described in relation to such, it is equally applicable for sealing off static installations under pressure in the ordinary way. It should be understood also that the invention can be adapted to manhole covers and the like of oblong, elliptical and square plan formations. It can also be adapted to traditional side hinged cover plates or doors, where the latter swing upwards clamshell fashion.

A further advantage of the cover plate of this invention is that the operative surfaces which require precision machining are protected from the weather in that they lie beneath the cover plate.

What is claimed is:

1. In a container for transport or storage of liquid in bulk having a filling opening defined by an upstanding neck, the combination of a cover plate having a depending flange, by which the cover plate, when in position, is located on said neck, and interlocking means for positively securing the cover plate to the neck including annular seating surfaces formed respectively on the neck and flange of the cover plate, said seating surfaces being angularly inclined relatively to the axis of said opening, a plurality of circumferentially arranged balls for operative engagement with said seating surfaces and by which the cover plate is positively held in position thereon, an annular cage encircling the neck and by means of which the balls are normally held in their operative position, said flange having an annular recess to receive the balls, the cage being capable of displacement by which the balls can be withdrawn from their operative position to a release position within said annular recess to permit removal of the cover plate.

2. A container as claimed in claim 1 in which the cover plate is provided with a sealing ring of L-shaped section, the base of the L having an inwardly projecting portion for engagement with a flat on the neck.

3. A container as claimed in claim 2 in which the neck is formed with an annular shoulder on the underside of which the seating surface for the balls is formed and with the upper side of which the sealing ring engages.

4. In a container for transport or storage of liquid in bulk having a filling opening defined by aneck thereon the combination of a cover plate having a dependent flange for engagement with the neck, a sealing ring on the flange for engagement with the neck to seal the contents against escape from the container, interlocking means for positively securing the cover plate to the neck including seating surfaces formed respectively on the flange and the neck and being similarly angularly inclined to the axis of said opening, a plurality of balls diametrically opposite sides of which abut said seating surfaces when in the closed position of the cover plate, an annular cage encircling the neck by which the balls are maintained in their operative position to hold the cover plate against release, said cage being capable of displacement byv which the sealing ring is disengaged and the balls can be withdrawn from their operative position to a release position within an annular recess in said flange to permit removal of the cover plate.

5. A container as claimed in claim 4 in which the sealing ring is of L-shaped section, the horizontal limb of the L having an inwardly projecting portion for engagement with the neck.

6. A cover plate as claimed in claim 4 in which the cover plate is provided with circumferentially spaced lugs for engagement with the neck by which it is located when in its closed position.

7. A cover plate as claimed in claim 4 wherein the cover plate is pivotally secured to the neck.

8. A cover plate as claimed in claim 7 in which the neck is formed with upstanding pins, one of which is 10. A cover plate as claimed in claim 8 in which sockets are provided on the inside of the neck to receive the pins.

111. A cover plate as claimed in claim 4 comprising a cage having elongated holes whereby the cover plate may be raised a distance sufficient to break the seal prior to withdrawal of the balls.

12. A container according to claim 4 in which the cage is provided with a handle for use when actuating the same to release the cover plate.

13. A container according to claim 4 in which a cam device is provided on the container for effecting release of the cover plate.

14. A container according to claim 4 in which an inner disc is secured to the underside of the cover plate, the disc having sealing engagement with the neck.

15. A container according to claim 1 in which the cover plate and the annular cage are provided with handles.

Claims

4. In a container for transport or storage of liquid in bulk having a filling opening defined by a neck thereon the combination of a cover plate having a dependent flange for engagement with the neck, a sealing ring on the flange for engagement with the neck to seal the contents against escape from the container, interlocking means for positively securing the cover plate to the neck including seating surfaces formed respectively on the flange and the neck and being similarly angularly inclined to the axis of said opening, a plurality of balls diametrically opposite sides of which abut said seating surfaces when in the closed position of the cover plate, an annular cage encircling the neck by which the balls are maintained in their operative position to hold the cover plate against release, said cage being capable of displacement by which the sealing ring is disengaged and the balls can be withdrawn from their operative position to a release position within an annular recess in said flange to permit removal of the cover plate.

8. A cover plate as claimed in claim 7 in which the neck is formed with upstanding pins, one of which is elongated to provide a fulcrum for the cover plate and about which it can be swung when lifted to a position in which it clears the short pin.

9. A cover plate as claimed in any of claim 8 in which the upward movement of the cover plate is spring assisted.

10. A cover plate as claimed in claim 8 in which sockets are provided on the inside of the neck to receive the pins.

11. A cover plate as claimed in claim 4 comprising a cage having elongated holes whereby the cover plate may be raIsed a distance sufficient to break the seal prior to withdrawal of the balls.