Patent Application
20150135643
1. Field of the Invention
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.
2. Description of the Related Art
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.
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.
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.
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.
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.
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.
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.
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.
Illustrative embodiments and exemplary applications will now be described with reference to the accompanying drawings to disclose the advantageous teachings of the present invention.
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.
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.
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.
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.
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.
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The pneumatic linear drive 24 in
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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.
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.
