Emptying station for bulk bags, and process of emptying bulk bags in the station

This emptying station is suited for emptying contents from bulk bags, especially bulk bags containing particulate hazardous materials as their contents. The emptying station includes a bulk-bag receptacle body having a top opening and bottom outlet, a bulk-bag cutting subassembly in the receptacle body, a raisable and lowerable top closure, and a sealing structure. The cutting subassembly includes at least three cutters each having an associated blade facing upwards, with the cutters collectively arranged to define a pyramid having an apex, and puncture pin positioned at the apex to point upwardly. In operation, a bulk bag is suspended from the top closure, then lowered with the top closure to pass the bulk bag into the receptacle body and cause the substantially flat bottom of the bulk bag to be pieced by the puncture pin and cut by the blades of the cutters to start emptying contents from the bulk bags to the bottom outlet. The sealing structure seals gaps formed between inner surfaces of the side walls and the bulk bag to prevent dust from escaping through the top opening. As the bulk bag is emptied, the top closure continues to lower until the top closure is positioned in a closed state in the top opening. Spray nozzles are preferably arranged in the receptacle body for external and/or internal rinsing of the emptied bulk bag.

CROSS-REFERENCE TO RELATED APPLICATION
 This application relates to German Application DE 199 37 700.6, filed Aug.
 10, 1999, the disclosure of which is incorporated herein by reference.
 BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The invention relates to an emptying station for bulk bags, in particular
 for bulk bags containing particulate hazardous materials, such as cyanuric
 chloride. The emptying station of this invention is especially useful for
 emptying bulk bags in a dust-free, safe manner and for rinsing the emptied
 bags.
 2. Description of the Related Art
 Various devices are known for emptying bulk bags, which as referred to
 herein mean large packaging containers which have in particular a capacity
 of from 100 to 1000 kg and are made of single-ply or multi-ply sacking
 material. U.S. Pat. No. 5,944,070 discusses one such device, which is
 purportedly useful for preventing problems arising during emptying of a
 bulk bag comprising an inner sack and an outer sack. The emptying device
 comprises a double-tube structure having an inner tube and an outer tube,
 a holding device arranged centrally above the inner tube for receiving a
 bulk bag, a raisable and lowerable closing ring for closing the upper end
 of an annular gap formed by the inner and outer tubes of the double-tube
 structure, and gripping and pulling devices for gripping and pulling taut
 the discharge neck of the inner sack. In operation, a bulk bag is inverted
 and lowered so that its outlet neck is gripped and pulled into the inner
 tube. The tie of the discharge neck can then be untied to release the
 contents of the bulk bag into the inner tube. Although this device allows
 safe emptying of powder-form bulk material, such as cyanuric chloride,
 handling of bulk materials with this device is rather complex. Another
 drawback of the device disclosed in U.S. Pat. No. 5,944,070 is that no
 provision is made for rinsing the emptied bulk bag before disposal of the
 emptied bulk bag.
 It is also known in the art to cut open the bottom of a bulk bag suspended
 from a carrier means by lowering the bulk bag onto an opening device to
 thereby empty the bulk bag. The opening device consists of commercially
 available cutters known as pyramid cutters. At least three cutters are
 used in the opening device, and in the case of bulk bags of substantially
 rectangular cross section, preferably four cutters are used. The cutters
 are arranged in a pyramid with their blades coming together at the top to
 form an apex of the pyramid. A pin is positioned at the pyramid apex for
 piercing the bottom of a bulk bag lowered onto the opening device. The
 pyramid cutters are conventionally arranged in a bulk bag receiving means
 provided with an outlet. During the opening operation, the bulk bag is
 lowered through a top opening of the bulk bag receiving means until the
 bulk bag is pierced then cut by the pin and cutters, respectively. During
 the emptying operation, a stationary rubber sleeve arranged between the
 bulk bag and the receiving means functions to reduce the amount of dust
 escaping through the top opening. The rubber sleeve is constructed as an
 inverted bowl or as a cylindrical element. However, the rubber sleeve is
 only partially effective, making devices equipped with the rubber sleeve
 unsatisfactory for emptying bulk bags filled with hazardous materials.
 Such emptying stations also lack means for rinsing out the bulk bag with a
 liquid rinsing agent immediately after emptying thereof. The absence of an
 effective rinsing means allows contents of the bulk bag to remain adhered
 to the sack wall after the emptying operation is complete, since no
 rinsing means is provided for dissolving or rinsing the residual contents
 away.
 SUMMARY OF THE INVENTION
 Accordingly, it is an object of the present invention to provide a bulk-bag
 emptying station which is suitable for safe, dust-free emptying of
 contents, especially hazardous materials, from bulk bags.
 In accordance with the principles of this invention, the above other
 objects are attained by the provision of a bulk-bag emptying station for
 emptying bulk bags having suspenders. The station comprises a bulk bag
 receptacle body comprising side walls. The side walls preferably form a
 box having a rectangular or square cross section and a sufficient height
 and volume to receive the bulk bag and suspenders thereof while leaving
 gaps between inner surfaces of the side walls and the bulk bag received
 therein. The receptacle body has a top opening configured to receive the
 bulk bag and a bottom outlet configured to dispense contents of the bulk
 bag. A bulk-bag cutting subassembly is accommodated in the bulk bag
 receptacle body and comprises at least three cutters and a puncture pin.
 Each of the cutters has an associated blade facing upwards, with the
 cutters collectively being arranged to define a pyramid having an apex,
 with the puncture pin positioned at the apex to point upwardly. The
 emptying station further comprises a top closure raisable into a receiving
 state in which the top closure is spaced from the receptacle body and
 lowerable into a closed state in which the top closure is received in the
 top opening. The top closure is engageable with the suspenders of the bulk
 bag so that raising and lowering of the top closure moves the bulk bag,
 when engaged to the top closure, out of and into contact with the cutting
 subassembly. A sealing structure positioned on the inner surfaces of the
 side walls of the receptacle body seals the gaps formed between the side
 walls and the bulk bag when the filled bulk bag is received in the
 receptable body.
 It is another object of the present invention to provide a bulk-bag
 emptying station which allows for dust-free emptying of hazardous
 materials from bulk bags and, subsequent to the emptying operation, allows
 for rinsing of the inner sack and optionally the outside of the outer
 sack. In accordance with the principles of this invention, the above and
 other objects are attained by providing the emptying station with one or
 more spray nozzles and one or more supply lines for supplying a rinsing
 agent to the spray nozzles. The spray nozzles are preferably positioned
 inside the pyramid, so that subsequent to opening a bulk bag with the
 cutting subassembly and emptying of the opened bulk bag, the inside of the
 bulk bag can be washed. Spray nozzles can also be positioned outside of
 the pyramid of cutters to rinse the outside of the bulk bags.
 It is still another object of the present invention to provide a process of
 emptying and cleaning a single- or multi-ply bulk bag having a
 substantially flat bottom and suspenders, especially bulk bags having
 hazardous contents, such as cyanuric chloride.
 In accordance with the principles of this invention, the above and other
 objects are attained by the provision of a process in which an emptying
 station is provided, the emptying station comprising a bulk-bag receptacle
 body including side walls and having a top opening and bottom outlet, a
 bulk-bag cutting subassembly accommodated in the receptacle body and
 comprising at least three cutters and a puncture pin, a raisable and
 lowerable top closure, and a sealing structure positioned on the inner
 surfaces of the side walls of the bulk bag receptacle body. The cutters
 each have an associated blade facing upwards and the cutters are
 collectively arranged to define a pyramid having an apex, with the
 puncture pin positioned at the apex to point upwardly. The suspenders of
 the bulk bag are coupled to the top closure, and the bulk bag is suspended
 from the top closure and spaced from the bulk bag cutting subassembly. The
 top closure and the bulk bag coupled thereto are then lowered so that the
 substantially flat bottom surface of the bulk bag is pierced by the
 puncture pin and cut by the blades of the cutters to begin emptying of the
 contents from the bulk bags. At the same time, the sealing structure seals
 the gaps formed between the inner surfaces of the side walls and the bulk
 bag. In this manner, the sealing structure prevents dust from escaping
 through the top opening, which is not yet sealed by the top closure. As
 the contents empty from the bulk bag, the top closure continues to move
 downward into a closed state in which the top closure is received in the
 top opening. Subsequent to emptying the bulk bag, the inside of the
 emptied bulk bag can optionally be rinsed with a rinsing agent sprayed
 from internal spray nozzles.
 Other objects, aspects and advantages of the invention will be apparent to
 those skilled in the art upon reading the specification and appended
 claims which, when read in conjunction with the accompanying drawings,
 explain the principles of this invention.

DETAILED DESCRIPTION OF THE INVENTION
 Referring now more particularly to the drawings, and in particular FIGS. 1
 and 2, there is shown an emptying station designed to empty bulk bags,
 especially bulk bags for storage of particulate hazardous contents.
 The emptying station comprises a bulk-bag receptacle body 1, which in the
 illustrated embodiment has four side walls 1a that collective form a box
 with a square cross section. Although the receptacle body 1 is illustrated
 as having a box shape, it should be understood that the receptacle body 1
 may undertake other shapes having fewer or more than four side walls 1a.
 For example, the side walls can be rounded to form a circular cross
 section. Similarly, the side walls 1a may have different lengths, such
 that the receptacle body 1 can have, for example, a rectangular cross
 section. It is particularly expedient to form the receptacle body 1 as a
 box having a rectangular or square cross section, since bulk bags 10 are
 commercially available with square and rectangular cross sections.
 Attached at the bottom surfaces of the side walls 1a is a funnel 2 and a
 bottom outlet 3, which is shown as a pipe. The bottom outlet 3 is
 positioned centrally relative to the funnel 2. The funnel 2 is preferably
 sealed at one end with the side walls 1a and at the other end with the
 outlet 3 to prevent escape of the particular contents of the bulk bags 10
 during emptying of the bulk bags 10. During emptying, this pipe connection
 is appropriately connected directly to, for example, a feed pipe
 connection of the reactor in which the bulk bag 10 contents are to undergo
 further reaction by means of, for example, a hose-type coupling.
 Accommodated inside of the receptacle body 1 is a bulk-bag cutting
 subassembly, which is generally designated by reference numeral 4. The
 cutting subassembly comprises at least three cutters, and in the
 illustrated embodiment four cutters 4a. Each of the cutters 4a has a
 respective blade (unnumbered) facing upwards. The cutters (also referred
 to herein as pyramid cutters) 4a are collectively arranged in the lower
 half, preferably the lower quarter, of the illustrated box, to form a
 pyramid having a top apex. A piercing pin 4b is arranged at the apex of
 the pyramid. In the illustrated embodiment, the piercing pin 4b is
 oriented vertically. The number of cutters 4a provided preferably
 corresponds to the number of lower corners of the box defined by the side
 walls 1a, with each of the lower corners having a corresponding cutter 4a
 extending therefrom. If the walls 1a are curved to provide a round or
 circular cross section to the receptacle body 1, the cutting subassembly 4
 preferably comprises at least three pyramid cutters spaced apart
 120.degree. from each other. The pyramid cutters 4a generally form an
 angle with the horizontal in the range of from 30.degree. to 75.degree.,
 in particular from 45.degree. to 60.degree.. The pyramid preferably has a
 height that is 0.5 to 2 times the width of the widest of the side walls
 1a. The upwardly directed blades of the pyramid cutters 4a allow the
 entire area of the bottom of the bulk bag 10 lowered thereon to be cut
 open.
 The emptying station further comprises a top closure 14 that is raisable
 into a receiving state (shown in FIG. 1) spaced from the bulk bag
 receptacle body 1 and lowerable into a closed state (shown in FIG. 3) in
 which the top closure 14 is received in the top opening of the receptacle
 body 1. The top closure 14 has a bottom surface with hooks 15 extending
 therefrom. On the upper surface of the top closure 14 is a carrier device
 16 from which said top closure 14 is suspendable. When raised above the
 receptacle body 1 as shown in FIG. 1, suspenders 12 of the bulk bag 10 can
 be coupled to the hooks 15 to suspend the bulk bag 10 from the top closure
 14. Conventionally, the suspenders 12 are holding straps or the like. In
 this manner, lowering and raising of the top closure 14 moves the bulk bag
 10 suspended therefrom into and out of the receptacle body 1.
 The height of the side walls 1a, measured from the base of the cutting
 subassembly 4, corresponds to at least the height of the bulk bag 10 and
 the outstretched suspenders 12. By providing the side walls 1a with a
 sufficient height, the entire filled bulk bag 10 can be accommodated in
 the receptacle body 1 and the top closure 14 can function as a lid,
 closing the top opening of the receptacle body 1. The cross section of the
 receptacle body 1 corresponds substantially to the cross section of the
 filled bulk bag 10, with an additional wall gap being present between the
 filled bulk bag 10 and the inner surfaces of the walls 1a to facilitate
 handling of the bulk bag 10 during raising and lowering operations.
 To prevent dust from escaping from the receptacle body 1, the receptacle
 body 1 includes a sealing structure 7 for sealing the gaps between the
 bulk bag 10 and the side walls 1a. As referred to herein, the sealing
 structure 7 can include strips located uniformly at one height as shown in
 FIG. 1, or a plurality of sealing strips arranged at different heights on
 the side walls 1a. The sealing structure 7 can include a single-part
 sealing lip or multi-part sealing lips. In the case of emptying stations
 with rectangular box cross sections, such as illustrated in FIG. 1, a
 suitable sealing structure 7 comprises a sealing plate 7a of a flexible
 material fixed to a flange 17 on each of the side walls 1a. The material
 for making the sealing plates 7a can be made, for example, of one of more
 of the following: natural and/or synthetic rubbers; flexible plastics such
 as polyolefins and polyamides; and silicone-rubber. The sealing plates 7a
 are pressed downwards upon lowering of the bulk bag 10 and thus seal the
 gap due to their positioning and flexibility and elasticity.
 The emptying station can optionally be equipped for rinsing the bulk bag 10
 subsequent to emptying of the contents from the bulk bags 10. Rinsing is
 often necessary to ensure safe disposal of the emptied bulk bags 10, such
 as for bulk bags 10 filled with hazardous materials as its contents.
 Although most of the residual contents typically remain on the inside of
 the bulk bags 10, it is also sometimes desirable to rinse the outsides of
 the bulk bags 10 subsequent to emptying, especially where hazardous
 material may adhere to the outside of the bulk bags 10. In order to
 perform these rinsing operations, the emptying station can be provided
 with one or more interior spray nozzles 6a and exterior spray nozzle 6b,
 together with a supply line or supply lines 9 for supplying a rinsing
 agent. Interior nozzles 6a arranged inside the pyramid of cutters 4a are
 useful for rinsing the insides of the bulk bags 10 subsequent to emptying.
 The interior spray nozzles 6a inside the pyramid of cutters 4a are
 arranged below imaginary planes in which the cutter blades lie. Although a
 plurality of interior spray nozzles 6a are illustrated, it is understood
 that only a single spray nozzle (or a number different than that
 illustrated) can be equipped in the emptying station. The interior nozzles
 6a are preferably oriented in such a way that the entire inner sack may be
 reliably rinsed out. The exterior spray nozzle 6b are positioned outside
 of the pyramid defined by the cutters 4a, and serve to rinse the outside
 or exterior of the bulk bags 10. As in the case of the interior spray
 nozzles 6a, one or a plurality of exterior spray nozzles 6b can be used.
 The supply lines 9 for the one or more spray nozzles are appropriately
 located inside the pyramid (or outside the pyramid for the external spray
 nozzles 6b) and preferably beneath one of the cutters.
 Operation of the emptying station to empty a bulk bag 10 according to the
 invention is described with reference to FIG. 3. As described above, prior
 to introduction of the bulk bag 10 into the receptacle body 1, the bulk
 bag 10 is suspended by its suspenders 12 from the hooks 15 of the top
 closure 14. (Although not shown, the top closure 14 is in turn carried by
 the carrier device 16.) The carrier device 16 and top closure 14 are
 manipulated to a position above the opening of the receptacle body 1, then
 are lowered until the bulk bag 10 is received in the receptacle body 1. As
 the bulk bag 10 enters into the receptacle body 1 and reaches the sealing
 structure 7, the sealing structure 7 is pressed downward by contact with
 the bulk bag 10 and the gap between the side walls 1a and the bulk bag 10
 is sealed, thereby preventing dust from escaping through the top opening.
 As the bulk bag 10 is lowered further, the weight of the filled bulk bag
 10 causes the pin 4b to pierce the bottom of the bulk bag 10 and, upon
 further downward movement of the bulk bag 10, the pyramid cutters 4a to
 cut open the entire bottom face of the bulk bag 10. Simultaneous with or
 subsequent to the bottom of the bulk bag 10 being pierced by the pin 4b
 and cut open by the cutters 4a, the top closure 12, which appropriately
 takes the form of a lid, closes the receptacle body 1 formed by the side
 walls 1a.
 The cut bottom of the bulk bag 10 takes the form of triangular flaps 11 due
 to the placement of the cutters 4a. The triangular flaps 11 formed by the
 cutting procedure drop downwards and allow discharge of the contents from
 the bulk bags 10 to commence. The contents drop into the funnel 2 and pass
 through the pipe connection 3 into a reactor (not shown) or other
 equipment designed to receive the bulk material. As the contents empty
 from the bulk bag 10, the top closure 12 continues to move downward with
 the bulk bag 10 until the top closure 12 seals the receptacle body 1.
 After emptying of the bulk bag 10, the bag 10 is rinsed by actuation of
 the nozzles 6, to which a liquid rinsing agent is supplied via the pipe
 connection 8 and the supply lines 9.
 It is expedient for the rinsing agent to be a solvent or suspending agent
 in the intended reaction. The quantity of rinsing agent entering the
 reactor (or other equipment downstream from outlet 3) in the form of the
 liquid rinsing agent is accordingly taken into account when the reactor is
 filled with liquid agent. Rinsing of the inside of the bulk bag not only
 prevents potential hazards, such as may arise during disposal of an
 unrinsed bulk bag, but at the same time makes the material supplied in the
 bulk bag available to the desired reaction without loss of material. After
 emptying the bulk bag 10, if required the exterior of the bulk bag also
 can be cleaned by means of spray nozzles incorporated in the side walls 1a
 and/or on the top closure 12. Once the rinsing process is complete, the
 emptied and rinsed bulk bag 10 is withdrawn from the receptacle body 10 by
 means of the carrier device 16. If organic solvents are used for rinsing,
 it is expedient to blow air through the inside of the bulk bag 10 after
 rinsing thereof, to remove any solvent residues (not illustrated).
 Bulk bags 10, as shown in FIG. 4 and which are suitable for filling with
 hazardous materials, generally comprise an inner sack 18 and an outer sack
 19. The inner sack 18 serves primarily to protect the bulk bag contents,
 but also should be sufficiently strong to hold the contents of the bulk
 bag 10. The outer sack 19 serves primarily to provide mechanical strength.
 The inner and outer sacks 18 and 19 are conventionally closed separately,
 by tying with tape 13 and/or other suitable means, such as adhesive or
 welding. Standard bulk bags 10 additionally comprise a plurality of
 suspenders 12, illustrated in FIG. 4 in the form of lifting straps 12a.
 The fixing seams 21 provide sufficient dimensional stability and strength
 to maintain the bottom 20 substantially flat.
 The emptying station according to the invention is distinguished from known
 stations by the simplicity and reliability of its structure. Occupational
 hygiene problems arising hitherto during the handling of hazardous
 materials are prevented. The contents of the bulk bag are fed to a reactor
 or other equipment through the outlet without loss of materials, since
 dust and the like are contained. Although not limited to any particular
 use, the emptying station according to the invention may be used for
 emptying bulk bags filled with cyanuric chloride, in which case water is
 preferably used as the rinsing agent, since many reactions involving
 cyanuric chloride are performed in the presence of water.
 The foregoing detailed description of the invention has been provided for
 the purpose of explaining the principles of the invention and its
 practical application, thereby enabling others skilled in the art to
 understand the invention for various embodiments and with various
 modifications as are suited to the particular use contemplated. This
 description is not intended to be exhaustive or to limit the invention to
 the precise embodiments disclosed. Modifications and equivalents will be
 apparent to practitioners skilled in this art and are encompassed within
 the spirit and scope of the appended claims.