Bag Lift Assembly for a Lined Bulk Material Container

Abstract

A lifting assembly for a polymeric liner disposed within a fluid material container. The assembly includes a pneumatic linear drive, and, an interface member that is supportively connecting to the polymeric liner. A tension line is coupled between the pneumatic linear drive and the interface member, and a line guide is positioned to route the tension line to a central location above the polymeric liner, and thereby correspondingly locates the interface member. A pneumatic controller actuates the pneumatic linear drive to move in a first direction, to move in a second direction, or to remain in a fixed position. Movement of the pneumatic linear drive in the first direction causes the tension line to lift the interface member in an upward direction, and, movement of the pneumatic linear drive in the second direction causes the tension line to lower the interface member in a downward direction.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to fluid material containers that are lined with a polymeric bag-type liner. More particularly, the present invention relates to an assembly for raising and lowering such a liner as it is filled or emptied, by using a pneumatic linear drive.

[0003] 2. Description of the Related Art

[0004] Storage and processing containers are in widespread use in various industries and other endeavors. Many of these are used to contain liquids and other flowable bulk materials, such as powders and granular materials. While containing certain types of fluid materials, it is preferable to line the container with a polymeric membrane so that the bulk material is either impermeably contained in a suitable polymeric material, or to insure that the bulk materials does not contact the container itself. For example, in the case of pharmaceutical and food grade materials, a polymeric liner, such as PVC or polypropylene, may be used to maintain the purity and cleanliness of the bulk material. In other instances, the bulk material may react with a storage container itself, so a polymeric liner is used to prevent such reactions.

[0005] Various fluid material containers can be employed, and one useful configuration is a rectangular stainless steel bin that has an open top. The liner is inserted from the top, and then plumbing connections are made to the bin and liner combination, as is known in the art. In other applications, the liner is inserted through a door of the host container. As the liquid, or fluid, is filled into the liner, it is necessary to control the position and movement of the liner to insure that it fits properly into the volume of the bin, and that the liner does not become improperly oriented or creased. If this occurs, then the liner may be damaged, or the maximum volumetric capacity of the bin and liner combination may not be realized. One approach to dealing with these potential problems has been to access the liner from the open top of the bin, and raise and lower it as the fluid material is added and removed from the bin. That way, improper fit can be adjusted before the liner becomes filled with the fluid material. Thus it can be appreciated that there is a need in the art for a system for mitigating the potential risk of filling and emptying bin liners in a manner that raises and lowers the liner during installation, filling, emptying and removal from a bin or other bulk material container.

SUMMARY OF THE INVENTION

[0006] The need in the art is addressed by the teaching of the present invention. The present disclosure teaches a lifting assembly for a polymeric liner that disposed within a fluid material container. The assembly includes a pneumatic linear drive, and an interface member that is adapted for supportively connecting to the polymeric liner. A tension line is coupled between the pneumatic linear drive and the interface member, and a line guide is positioned to route the tension line to a central location above the polymeric liner, which thereby correspondingly locates the interface member. A pneumatic controller actuates the pneumatic linear drive to move in a first direction, to move in a second direction, or to remain in a fixed position. Movement of the pneumatic linear drive in the first direction causes the tension line to lift the interface member in an upward direction, and, movement of the pneumatic linear drive in the second direction causes the tension line to lower the interface member in a downward direction.

[0007] In a specific embodiment of the foregoing assembly, where the polymeric liner is a bag structure that includes support fitments, the interface member includes at least a first connector adapted to engage the support fitments. In a refinement to this embodiment, where the support fitments are selected from a loop of polymeric material, an eyelet inserted through the polymeric material, and a reinforced portion, the first connector is selected from a hook, a ring, a karabiner, and a clamp.

[0008] In a specific embodiment of the foregoing assembly, where the fluid material container is a rigid structure with an open top, the interface member is inserted through the open top. In another specific embodiment, the pneumatic linear drive is a rodless pneumatic cylinder.

[0009] In a specific embodiment of the foregoing assembly, the interface member is a spider structure with a central joint that is connected to the line guide with spider arms extending outwardly, which are connected to the polymeric liner. In another specific embodiment, the tension line is a cable. In another specific embodiment, the line guide includes a pulley, around which the tension line is routed.

[0010] In a specific embodiment, the foregoing assembly further includes a housing that contains the pneumatic linear drive, and which is configured for mounting to the fluid material container. In a refinement to this embodiment, the housing includes a line guide support member, which orients the line guide at the central location above the polymeric liner. In a further refinement, the line guide support member extends as a cantilever from the housing to the central location.

[0011] In a specific embodiment of the foregoing assembly, the pneumatic controller is a three-position, four-port, pneumatic valve with a closed center position. In another specific embodiment, the pneumatic controller is coupled within a pneumatic circuit that has a regulated pressure, and the pneumatic circuit further include a relief valve set to a pressure less than twenty percent greater than the regulated pressure, thereby limiting the maximum force exerted by the pneumatic linear drive. In a refinement to this embodiment, the assembly further includes a flow control orifice coupled to an exhaust port of the pneumatic controller, thereby controlling the rate of movement of the pneumatic linear drive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a perspective view drawing of a bag-lined fluid material container according to an illustrative embodiment of the present invention

[0013] FIG. 2 is a top view drawing of a bag-lined fluid material container according to an illustrative embodiment of the present invention.

[0014] FIG. 3 is a side view drawing of a pneumatic bag lift assembly according to an illustrative embodiment of the present invention.

[0015] FIG. 4 is a side view drawing of a pneumatic bag lift assembly according to an illustrative embodiment of the present invention.

[0016] FIG. 5 is a functional diagram of a pneumatic bag lift assembly according to an illustrative embodiment of the present invention.

[0017] FIG. 6 is a pneumatic schematic of a bag lift assembly according to an illustrative embodiment of the present invention.

DESCRIPTION OF THE INVENTION

[0018] Illustrative embodiments and exemplary applications will now be described with reference to the accompanying drawings to disclose the advantageous teachings of the present invention.

[0019] While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope hereof and additional fields in which the present invention would be of significant utility.

[0020] In considering the detailed embodiments of the present invention, it will be observed that the present invention resides primarily in combinations of steps to accomplish various methods or components to form various apparatus and systems. Accordingly, the apparatus and system components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the disclosures contained herein.

[0021] In this disclosure, relational terms such as first and second, top and bottom, upper and lower, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0022] An illustrative embodiment of the present invention is applied to the pharmaceutical industry, and in particular, processing bins that employ polymeric liners to impermeably retain a fluid content, which is commonly a liquid. Such processing and storage bins are commonly fabricated from stainless steel, for the benefits of corrosion resistance, sanitation, and durability. The polymeric liners are generally flexible bag-like structures that can be replaced from time to time. Such replacement may occur through an open top of the container, or through door openings located through the container walls. For this and other reasons, the exterior walls of such containers may have doors installed for access to the interior. Such doors contain the polymeric liner in the same fashion as the walls. The liners are fabricated to the same dimensions and shape as the interior of the host container, which is commonly rectangular. As such, it is important to position and orient the liner in a manner that will allow the form-fitted liner to fill and fit the interior shape of the container. Lifting the top of the liner, so as to `stretch` it out and enable the liner membrane to fit neatly into the container as it is filled, can facilitate this. A similar issue may present itself as the liner is emptied of fluid, as well as while the liner fluid volume fluctuates during production and operations.

[0023] In general, the assembly of this disclosure comprises is a device to lift the top of a bag, or liner, inside a bin or bag holder, that holds the bag up while filling the bag with product and while discharging the product. The illustrative embodiment assembly consists of a pneumatic rodless cylinder contained within a vertical housing, so as to be completely concealed, with a cable that is routed up to the top of the vertical tube, through a horizontal tube, exiting in a vertical direction, and connected to a lifting frame, referred to as a `spider`, which reaches out to the four corners of the bag. A pneumatic hand valve controls flow of air to the pneumatic cylinder. When the carriage of the rodless cylinder travels up the spider travels down, and when the carriage of the rodless cylinder travels down, the spider travels up. Additionally, the pneumatic line coupled to drive the pneumatic cylinder that raises the spider includes a pressure relief valve, which is set to provide only slightly more pressure than is needed to lift and hold the bag up. If more pulling force is exerted on the bag lift, the pressure relief valve relieves, allowing the spider to lower, preventing too much force from being exerted on either the bag or the bag lift structure itself.

[0024] Reference is directed to FIG. 1, which is a perspective view drawing of a bag-lined fluid material container according to an illustrative embodiment of the present invention. The bulk material container 2 is fabricated from stainless steel, and employs and exterior frame 4 made from structural shapes. Stainless steel sheet or plate 3 is applied to the frame and yields a generally smooth interior surface. The container has an open top 5, and an access door 6 located on one of its exterior walls. Other process related fixtures are illustrated, but are not germane to the present disclosure. A stainless steel housing 8 is fixed to a corner of the container 2 using plural mounting clips 11 to removably engage the housing 8 to the container 2. The housing 8 is elongated and oriented in a generally vertical orientation. Other orientations can be employed, including orientations where the housing 8 is not directly connected to the container 2. A pneumatic linear drive (not shown) is disposed within the housing 8, and includes certain pneumatic circuit components (not shown). Access to the interior of the housing 8 is provided by plural covered access openings 9. In addition, a control housing 10 is fabricated as a portion of the housing 8 for containing control valves (not shown) and other pneumatic components (not shown).

[0025] The housing 8 in FIG. 1 serves as a mounting location for a line guide support member 12, which has the form of a cantilevered structural arm in the illustrative embodiment. A tension line 13 is supported by the line guide support member 12 using one or more line guides (not shown), and with tension line routing also managed using the line guides (not shown). In the illustrative embodiment, the tension line 13 is a stainless steel cable, the line guides are pulleys, and the line guide support member 12 is a structural tube. The tension line 13 is positioned near the central area of the open top 5, and is oriented in a vertical direction. The tension line 13 is coupled to a spider structure 14, which as four arms that extend toward the four corners of the open top 5 of the container 2. In the illustrative embodiment, the spider structure 14 is fabricated from stainless steel tubing with reinforcing gussets to strengthen connections. The end of each spider structure 14 arm is terminated with a connector 16. The connectors 16 attached to support fitments (not shown), which are a component of the bag liner (shown in phantom) 18 in FIG. 1.

[0026] Reference is directed to FIG. 2, which is a top view drawing of a bag-lined fluid material container 2 according to an illustrative embodiment of the present invention. The structural frame 4 of the container 2 is presented, with the stainless sidewalls 3 visible as well. The housing 8 of the bag lift assembly is connected to the exterior of the container 2, and a cantilevered line guide support member 12 extends to the central areas of the open top of the container 2. A control housing 10 extends from the side the housing 8. The spider structure 14 extends to the four corners of the container 2. There are connectors 16 at the end of each spider arm 14, and in this embodiment the connectors 16 are rings, which engage support fitments (not shown) of the bag liner (also not shown). The spider assembly 14 travels up and down inside the container 2, and serves to lift and extend the bag liner (not shown). The weight of the spider 14 and bag liner (not shown) are carried by the cantilevered line guide support member 12, which is supported, in turn, by the housing 8.

[0027] Reference is directed to FIG. 3 and FIG. 4, which are a side view drawing of a pneumatic bag lift assembly according to an illustrative embodiment of the present invention. FIG. 3 illustrates the spider assembly 14 in the lowest position and FIG. 4 illustrates the spider assembly 14 in the highest position. Both figures illustrate the entire bag lift assembly without showing the host bulk fluid material container or the bag liner. An elongated stainless steel housing 8, which has a rectangular cross section, contains a pneumatic linear drive (not shown), and includes a control housing 10 for containing certain pneumatic controls, including an operator 19 for a pneumatic valve contained therein. The housing includes plural access openings 9 with removable covers for enabling access to internal components. A cantilevered line guide support member 12 extends laterally from the top of the housing 8. In the illustrative embodiment, the line guide support member 12 is a rectangular stainless steel tube. The line guide support member 12 includes a pulley 20 at its distal end, which serves to route the tension line 13 to a vertical orientation. The tension member 13 in the illustrative embodiment is a stainless steel cable, although other manner of chain, cordage, and wire could be employed with suitable effectiveness. The tension line 13 is connected to a central point of bag interface member, or spider frame, 14. The spider frame 14 is fabricated from stainless steel tubing with reinforcing gussets in the illustrative embodiment. The distal ends of the spider frame 14 arms have connectors 16 for connection to the bag liner (not shown). The connectors may be rings, hooks, clamps or karabiners, whichever is most suitable for particular support fitments present on the specific bad liner being supported. The bag liner support fitments may be a loop of polymeric material, a reinforced portion of polymeric material, eyelets, or other support fitments as are known to those skilled in the art. The key feature of the connectors 16 is that they are adapted to supportively engage these support fitments.

[0028] Reference is directed to FIG. 5, which is a functional diagram of a pneumatic bag lift assembly according to an illustrative embodiment of the present invention. The bulk material container 2 is lined with a polymeric bag liner 18, which is partially filled with a liquid 46 in this illustration. The bag interface member 14 supports the upper portion of the bag liner 18 using plural connectors 16, which are connected to support fitments 24 that are included with the bag liner 18. In this embodiment, the connectors 16 are stainless steel rings and the support fitments 24 are reinforced tabs having grommets inserted there through. The interface member 14 is a spider frame that is connected to a tension line 13, which is a stainless steel cable in this embodiment. The tension line is routed over two pulleys 20, 22. Pulley 20 is supported at the distal end of the line guide support member 13, and pulley 22 is supported at the upper end of housing 8. These pulleys 20, 22 serve to route the tension line 13 between vertical and horizontal orientation, as illustrated. The tension line 13 is terminated at a moving carriage 26 on a pneumatic linear drive 24, which is a rodless pneumatic cylinder in the illustrative embodiment. In the illustrative embodiment, the rodless pneumatic cylinder is a Festo Corporation Series DGL linear drive having a 25 mm bore, and a length selected to match the corresponding container 2 height and bag 18 size. Festo Corporation has a US headquarters in Hauppauge, N.Y. and a web presence at www.festo.com. The pneumatic linear drive 24 is mounted within housing 8, which is mounted to the bulk container 2 using plural mounting brackets 11.

[0029] The pneumatic linear drive 24 in FIG. 5 is fixed within the housing 8, and includes pneumatic line connections at interface ports 44. A first pneumatic line 40 drives the carriage 26 up, and a second pneumatic line 42 drives the carriage 26 down. The pulleys 22, 20 route the tension line 13 to cause the spider 14 to move in the opposite direction of the carriage 26. A control housing 10 is added as an appendage to the housing 8, and provides a space for certain pneumatic elements. Among these is a 3-position, 4-port, center-closed, control valve 34, which presents an operator handle 19 on the exterior of control housing 10. Also included is a pressure relief valve 32 and a flow control orifice 36. In addition, a pressure regulator 30 receives line pressure 28 from an external source, and delivers regulated air pressure to the control valve 34 through pneumatic line 38. Further details of the pneumatic circuit will be discussed herein after.

[0030] Reference is directed to FIG. 6, which is a pneumatic schematic of a bag lift assembly according to an illustrative embodiment of the present invention. An air supply line 28 delivers compressed air, typically in the 80-100 psi pressure range, which is regulated to approximately 50 psi by pressure regulator 30. The regulated air is coupled via supply line 30 to an input port of control valve 34, which is a 3-position, 4-port, valve 34, and which has a closed center position. The control valve 34 is selectively operated by actuator 19. The control valve 34 drives both input ports of the pneumatic linear actuator through air lines 40 and 42. This is a conventional pneumatic cylinder drive arrangement, as is know to those skilled in the art. The line 40, which drives the aforementioned interface member upwardly, is coupled to a pressure relief valve 32, which is set to a nominal 55 psi. Note that this pressure is slightly higher than the supply line 38 pressure of 50 psi. This arrangement limits the force that can be imparted to the lifting operation of the assembly, and serves to prevent damage to the aforementioned line guide, tension line, interface member, and the bag liner itself. The range of up to twenty percent over pressure is suitable. The line 42, which is used to lower the assembly generally does not require over-pressure protection. The exhaust line 39 out of the control valve 34 is routed through a flow limited orifice 36. This serves to limit the rate at which the assembly moves during exhaust limited movement.

[0031] Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof.

[0032] It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention.

Claims

1. A lifting assembly for a polymeric liner disposed within a fluid material container, comprising: a pneumatic linear drive; an interface member adapted for supportive connection to the polymeric liner; a tension line coupled between said pneumatic linear drive and said interface member; a line guide positioned to route said tension line to a central location above the polymeric liner, thereby correspondingly locating said interface member; a pneumatic controller coupled to actuate said pneumatic linear drive to move in a first direction, to move in a second direction, or to remain in a fixed position, and wherein movement of said pneumatic linear drive in said first direction causes said tension line to lift said interface member in an upward direction, and, movement of said pneumatic linear drive in said second direction causes said tension line to lower said interface member in an downward direction.

2. The assembly of claim 1, and wherein the polymeric liner is a bag structure that includes support fitments, and wherein said interface member includes at least a first connector adapted to engage the support fitments.

3. The assembly of claim 2, and wherein the support fitments are selected from a loop of polymeric material, an eyelet inserted through the polymeric material and a reinforced portion, and wherein said at least a first connector is selected from a hook, a ring, a karabiner, and a clamp.

4. The assembly of claim 1, and wherein the fluid material container is a rigid structure with an open top, and wherein: said interface member is inserted through the open top.

5. The assembly of claim 1, and wherein: said pneumatic linear drive is a rodless pneumatic cylinder.

6. The assembly of claim 1, and wherein: said interface member is a spider structure with a central joint that is connected to said tension line with spider arms extending outwardly, which are connected to the polymeric liner.

7. The assembly of claim 1, and wherein: said tension line is a cable.

8. The assembly of claim 1, and wherein: said line guide includes a pulley, around which said tension lines is routed.

9. The assembly of claim 1, further comprising: a housing, having said pneumatic linear drive disposed therein, and which is adapted for mounting to the fluid material container.

10. The assembly of claim 9, and wherein: said housing comprises a line guide support member, which orients said line guide at said central location above the polymeric liner.

11. The assembly of claim 10, and wherein: said line guide support member extends as a cantilever from said housing to said central location.

12. The assembly of claim 1, and wherein: said pneumatic controller is a three-position, four-port, pneumatic valve with a closed center position.

13. The assembly of claim 1, and wherein: said pneumatic controller is coupled within a pneumatic circuit that has a regulated pressure, and wherein said pneumatic circuit further include a relief valve set to a pressure less than twenty percent greater than said regulated pressure, thereby limited the maximum force exerted by said pneumatic linear drive.

14. The assembly of claim 13, further comprising: a flow control orifice coupled to an exhaust port of said pneumatic controller, thereby controlling the rate of movement of said pneumatic linear drive.