GB2044718A

GB2044718A - Apparatus for Lifting and Sealingly Locating a Drum Against an Aperture

Info

Publication number: GB2044718A
Application number: GB7942527A
Authority: GB
Original assignee: Kernforschungszentrum Karlsruhe GmbH
Current assignee: Forschungszentrum Karlsruhe GmbH
Priority date: 1978-12-28
Filing date: 1979-12-10
Publication date: 1980-10-22
Also published as: DE2856465C2; DE2856465A1; FR2445592B1; GB2044718B; CH650095A5; FR2445592A1

Abstract

There is disclosed apparatus for pressing into position an ironhooped drum against an aperture provided in the base of a hot cell or glove box used for processing material, preferably radio-active material, and being sealable by means of the double cover technique, the apparatus comprising at least two lifting devices (6, 7) operating independently of each other and securable to the floor or ground, such devices being utilised for raising and pre-positioning the drum (1) closely below the charging aperture (2) of the cell, and at least two further lifting and pressing devices (4, 5) which are securable to the base (3) of the cell from below for precise positioning and pressing the drum against the sealing surface of the cell base (3). <IMAGE>

Description

SPECIFICATION Apparatus for Sealingly Locating a Waste Drum Against an Aperture The present invention relates to an apparatus for pressing into position an ironhooped drum against an aperture provided in the base of a hot cell or glove box used for processing material, preferably radioactive material, and being sealable by means of the double cover technique, said apparatus having at least one lifting or pressing device for applying the drum against the sealing surface below the aperture of the base wall of the hot cell or glove box.

The present invention relates to the flange connection of waste drums to double cover locks of hot cells or glove boxes in which radioactive material is processed. In hitherto known double cover locks for waste drums, each drum is placed on a lifting device which lifts it mechanically, hydraulically or pneumatically and presses it against the double cover lock or the charging aperture. If such a lifting device is rigidly located beneath the double cover lock, the drum can only be positioned with a floor conveyor vehicle fitted with forks. Transferring from a conveyor vehicle to the lifting device is most cases is not possible owing to the weight of the drum and the difficulty of access beneath the processing plant or cells or glove boxes.If the lifting device is located separately on a conveyor vehicle which positions the drum below the lock or charging aperture, the drum has to be mounted with a separate lifting tackle or a floor conveyor vehicle fitted with forks.

Furthermore, the upper cover of a double cover system, which is mounted in the lock aperture, can only be connected to the lower cover of the double cover system associated with the drum when the drum is accurately positioned. This positioning, in the case of a lifting device rigidly mounted beneath the lock, is attempted by means of stops and guide cones. The pressure plate on which the drum is located to balance to drum tolerances is, in most cases, centrally mounted in a sphere. With this, however, it is not possible to balance all tolerances since the friction between drum and pressure plate prevents any sliding over this plate. Consequently, the drum has to be coupled repeatedly to the double cover lock until the two closure covers of the double cover lock system can be connected to each other.In the case of the lifting and pressing device on the conveyor vehicle, the difficulty of accurate positioning is increased with varying drum weight and hence, furthermore, makes accurate positioning difficult. Double cover locks are used for the handling of material which on account of its danger aspect has to be sealed from the surrounding atmosphere. This means that the sealed flange connection of the drum to the double cover lock is of the greatest importance.

The above-described devices, which have considerable drum tolerances, lead to unequal surface pressures at the seal between the drum and double cover lock or its seal and hence cause leakages. In the case of hydraulicaliy or pneumatically displaced lifting and pressing devices in the known apparatus, auxiliary mechanical retaining structures are required in order during an energy or driving medium failure, not to reduce the surface pressure against the seal between drum and lock seal, so that sufficient sealing is ensured. Finally, the pressure force has to be diverted from the double cover lock via supports or the like.

It is an object of the present invention to provide an apparatus of the kind described above in which the disadvantages stated are at least minimized. It is of particular importance that the conveying of the drum may be carried out with any type of floor conveyor vehicle, that an accurate fit of the drum on the double cover lock is ensured, so that the cover of the lock may be simply and reliably coupled to the cover of the drum. Moreover, an accurate fit of the drum on the double cover lock with uniform surface pressure over its circumference has to be ensured to obtain a satisfactory seal.

According to the present invention there is provided apparatus for pressing into position an ironhooped drum against an aperture provided in the base of a hot cell or glove box used for processing material, and being sealable by means of the double cover technique, said apparatus having at least one lifting or pressing device for applying the drum against the sealing surface below the aperture in the cell, in which at least two lifting devices operating independently of each other and securable to the floor are provided for raising and pre-positioning the drum closely below the charging aperture, and at least two further lifting and pressing devices adapted to be secured from below to the base of the cell for precise positioning and pressing against the sealing surface of the cell base.

The invention further proposes in a preferred embodiment that the lifting devices for raising and pre-positioning the drum are provided with arcuate forks which are adapted to the outer wall surface of the drum to be lifted and which embraces some at right angles and engage beneath a lower iron hoop of the drum.

Preferably, the lifting and pressing devices for precise positioning of the drum have arcuate tongs, the inside edge of which is adapted to the outer wall surface of the drum and embraces it at right angles, whereby the tongs engage below the upper edge or hoop of the drum, the lifting and pressing devices being actuated by means of a double bell crank lever arrangement and are locked positively in their pressure application position. It is of particular advantage for the bell crank lever mechanism to be comprised of two series connected bell crank levers, the first lever being directly actuated on one of its shanks by a pressure cylinder, and by means of the other of its shanks via a roller, presses upwardly against the second lever which supports the tongs, and in which this second shank in the pressing-in position faces vertically downwards.

With a pressure device adapted in such a manner there is a free choice of the conveyor means for the drum. The drum may also be gripped beneath its sealing flange. This produces a simple and reliable centering of the drum relative to the double cover lock without taking into account any possible drum tolerances existing, and a uniform abutment of the drum against the double cover lock. By using a pressing device with a dead centre position, minor tolerances may be compensated and locking attained even if the auxiliary devices fail. In this manner, a substantially more reliable operation of the double cover lock is made possible, since it is no longer necessary to take the drum tolerances into account.Due to the combination of the centering and pressure application device with the double cover lock complex, adjustment operations of the drum below the charging aperture of the lock are hence dispensed with.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawing, in which the single Figure is a schematic side view, partly in section, of an apparatus in accordance with the invention.

As illustrated, the apparatus in accordance with the invention for pressing ironhooped drums 1 against an aperture 2 in the base wall 3 of a hot cell or a glove box, not shown in detail, is comprised of four lifting devices 4 and 5 and 6 and 7, arranged in pairs. The interior space of the hot cell or glove box, in which radioactive waste is preferably to be processed, is denoted by the numeral 8. The so processed waste material is then charged into a drum 1 for further treatment.

The aperture 2 in the base 3 and the corresponding aperture of the drum 1 are sealed off by a so-called "double cover" lock system which is known and does not form the subject matter of the present invention.

Two pairs of lifting devices 4 and 5 and 6 and 7, are provided for connecting the drum 1 to the coupling member 9 connected to the base wall 3.

Two of the lifting devices, viz. 4 and 5 or 6 and 7 are structurally identical but offset relative to each other by 1800 of the drum circumference. The two lower lifting devices 6 and 7 are comprised of cylinders 11 secured to the floor or ground 10, which cylinders are hydraulically or pneumatically actuated. The pistons 12 of the lifting devices 6 and 7 support arcuate forks 13 which engage beneath the iron hoops 14 of the drum 1 and lift it to closely below the sealing surface 30 of the coupling member 9 (left hand side of Figure). This operation serves for the pre-positioning of the drum 1, whereby the forks 1 3 are drawn slightly around the circumference of the drum 1 and are adapted to the outer wall surface 28 thereof and hence effect a certain pre-centering below the aperture 2.

The actual centering and pressing operation occurs with the aid of the upper lifting and pressing devices 4 and 5 respectively, the anchoring plate 1 5 each of which is securely screwed from below against the base wall 3. A tensioning mechanism, which functions in the manner of a double bell crank lever having a dead centre position is mounted on the anchor plate.

The mechanism is chiefly comprised of a bell crank lever 1 6 which is pivotably connected to the anchor plate 15 about pivot 17, and one shank 18 of the lever 16 is connected to the connecting rod of a working cylinder 19. The other shank 20 of the bell crank lever 16 supports a roller 21 which presses from below against lever 22, which in turn actuates tensioning or pressure application tongs 23. The inside edge of the tongs 23 is adapted to the outer wall surface 28 of the drum 1 and engages same at right angles. The actuation of the tongs or arcuate pincers 23, which by means of the shaft 24 are also pivotably connected to the anchor plate 15, consists of an upward pivotal movement. Springloaded pins 25, located on the tongs 23, engage beneath the upper hoop 26 of the drum 1 and permit it to be pressed from below against the coupling member 9.Sealing is attained by means of sealing member 27 placed on the hoop 26 of the drum.

For applying pressure, the dead centre position of the bell crank lever 6 is important. The lever 16, in the pressure position, is so adjusted that its shank 20 with the roller 21 points vertically downwards and the pressure roller 21 presses upwardly against the lever 22. In this way the tongs 23, via the lever 22, are substantially positively locked, i.e. it is impossible for the drum 1 to drop off the aperture 2 even with a failure of the driving medium in the cylinder 19. This position is shown on the right-hand side of the Figure for the lifting and tensioning or pressing device 5. On the left, the device 4 is shown in the open position, i.e. the drum 1 is located closely below the aperture 2 and is retained and prepositioned by the lifting device 6.

Summarised, the function of the present invention is as follows: the waste drum is conveyed by means of a conveying vehicle (forklift truck, fork stacker, palette trolley or the like) below the double cover lock of a hot cell and roughly positioned. By means of a lifting device, the drum is engaged at the lower iron hoop thereof and lifted to closely below the sealing surface on the double cover lock. The centering and pressing operation is now taken over by pressure application device which is coupled directly to the double cover lock and fixed thereto from below.

Claims

1. Apparatus for pressing into position an ironhooped drum against an aperture provided in the base of a hot cell or glove box used for processing material, and being sealable by means of the double cover technique, said apparatus having at least one lifting or pressing device for applying the drum against the sealing surface below the aperture in the cell, in which at least two lifting devices operating independently of each other and securable to the floor are provided for raising and pre-positioning the drum closely below the charging aperture, and at least two further lifting and pressing devices adapted to be secured from below to the base of the cell for precise positioning and pressing against the sealing surface of the cell base.

2. Apparatus as claimed in claim 1, in which the lifting devices for raising and pre-positioning the drum have arcuate forks for lifting which are adapted to the outer wall surface of the drum to be lifted, embracing the latter at right angles and engaging below a lower iron hoop of the drum.

3. Apparatus as claimed in claim 1 or 2, in which the lifting and pressing devices for precise positioning of the drum have tongs, the inside edge of which is adapted to the drum circumference and which engage the drum at right angles, whereby the tongs engage below the upper edge or hoop of the drum, the lifting and pressing devices being adapted to be actuated by means of a double bell crank lever arrangement and adapted to be locked positively in their pressing-in position.

4. Apparatus as claimed in claim 3, in which the bell crank lever mechanism is comprised of two series connected bell crank levers, the first lever being directly actuated on one of its shanks by a pressure cylinder, and by means of the other of its shanks presses, via a roller, upwardly against the second lever which supports the tongs, and in which this second shank in the pressing-in position faces vertically downwards.

5. Apparatus for pressing into position an ironhooped drum against an aperture provided in the base of a hot cell or glove box used for processing material, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.