Patent Description:
A variety of industries incorporate a follower plate into an apparatus, i.e., a drum unloader, that is configured to evacuate a viscous material, such as a hot melt adhesive and the like from a drum or other storage container. The follower plate generally includes a surface and a central aperture. The surface of the follower plate forces the melted adhesive to flow through the central aperture into the inlet of a pump, which moves the adhesive to other fluid handling equipment near the point of its application onto the surface of a substrate.

One potential problem with this type of apparatus is the number of operator injuries that occur if the follower plate is allowed to move downward when the follower plate is located outside the confines of the storage container. Other potential problems may also occur when using this type of apparatus. These other potential problems include: (i) over-pressurization of the storage container, which results in the container either becoming deformed and/or ruptured; (ii) the generation of material waste caused by leaving residual material in the storage material and/or the dripping of viscous material from the follower plate when it is external to the container during replacement of an empty container with a full storage container; and (iii) the occurrence of an injury to the operator if he/she comes into physical contact with the hot viscous material.

<CIT> discloses a conveying unit that has an actuating unit and a follow-up plate having a flow opening for a fluid, where the follow-up plate is movable by the actuating unit in the direction of a base of the container under the conveying of fluid through the flow opening. A control unit is adapted to receive signals from a sensor and control the actuating unit depending on the signal to move away the follow-up plate from the base.

<CIT> discloses a method and system of reducing the residual quantity in the transfer of a viscous fluid.

<CIT> discloses a device for conveying viscous material from a barrel-like container which has a base and a peripheral wall extending from the base to an open upper edge of the container. The device has a follower plate which has a material outlet connected to a feed pump and is intended to close the container, wherein the follower plate is movable up and down in the container with sealing abutment on an inner surface of the container wall facing it, and a lifting device with a drive unit for raising and lowering the follower plate.

The present disclosure generally provides an apparatus for forcing a viscous material to flow from a storage container. This apparatus generally comprises a follower plate configured to be inserted into an open-end of the storage container; a sealing element located around the outer periphery of the follower plate; a pump assembly that includes a pump, an air motor, and a pipe or tube that is in fluid communication with the follower plate; a support stand comprising a base, a crossbar; and two or more cylinders with rods inserted therein; one or more control systems; and a safety mechanism according to the first aspect below configured to reversibly allow or prevent the air pressure from being supplied to the air motor depending upon the position of the follower plate. The follower plate may be located in a position that is either outside or inside the storage container. The sealing element is configured to provide a leak-proof seal with the storage container when the follower plate is located inside the storage container. The air motor is supplied with a source of air pressure and the cylinders and rods are configured to move the follower plate up or down based on air pressure supplied thereto.

In a first aspect of the present disclosure according to claim <NUM>, a safety mechanism comprises a first valve configured to reversibly switch between on and off in order to allow or prevent air pressure from flowing from a source to the air motor-driven pump assembly; at least one device configured to measure the position of the follower plate relative to the storage container; and a second valve that is in communication with the first valve and the device. The second valve is configured to instruct the first valve to prevent air pressure from being supplied to the air motor-driven pump assembly when the follower plate is external to the storage container. The second valve is further configured to instruct the first valve to allow air pressure from the source to be supplied to the air motor-driven pump assembly when the follower plate is within the storage container.

In a second aspect of the present disclosure according to claim <NUM>, a method of removing the viscous material from a storage container is provided. This method generally comprises the steps of:.

The present disclosure generally provides a safety mechanism for use in an apparatus, such as a drum unloader, that forces a viscous material to flow from a storage container is provided. This safety mechanism prevents air pressure from being supplied to the air motor-driven pump assembly when the follower plate is not located within the storage container. Thus, this safety mechanism reduces the potential of operator injuries that may occur from a pinch point that exists at the inlet of the pump assembly due to the inlet being accessible to contact with an operator when it is not within the storage container.

The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. For example, the safety mechanism made and used according to the teachings contained herein is described throughout the present disclosure in conjunction with an apparatus that dispenses a hot melt adhesive in order to more fully illustrate the composition and the use thereof. The incorporation and use of such a safety mechanism in an apparatus that dispenses other viscous materials, such as other adhesives, sealants, syrups, gels, pastes, mastics, gums, or the like from a storage container is contemplated to be within the scope of the present disclosure. It should be understood that throughout the description, corresponding reference numerals indicate like or corresponding parts and features.

Referring to <FIG>, an apparatus <NUM> configured to force a viscous material <NUM> from a bulk storage container <NUM> is provided. This apparatus <NUM>, generally, comprises a follower plate <NUM> as described above and further defined herein, a pump assembly <NUM> that includes an air motor <NUM> a pump <NUM>, and a pipe <NUM> or tube that is in fluid communication with the follower plate <NUM>; at least one control system <NUM>; and a support stand <NUM> that includes a base <NUM>, two or more upright cylinders <NUM> and rods <NUM> associated therewith, and one or more support crossbars <NUM>. The cylinders <NUM> and rods <NUM> are configured to move the follower plate <NUM> up or down based on air pressure supplied thereto. When desirable, the base <NUM> may be designed such that it provides support for the bulk storage container <NUM>. One skilled in the art will understood that additional support members connected between cylinders <NUM> and base <NUM> may be used when necessary or desirable.

The pump assembly <NUM> includes an air-operated motor <NUM> driven pump <NUM> supplied with air from a pressurized source, as well as a pipe <NUM> or tube that is in fluid communication with the follower plate <NUM>. The pump <NUM> is generally a positive displacement type pump, including but not limited to, a piston pump, a gear or rotary lobe pump, a rotary vane pump, or a diaphragm pump.

The control system <NUM> integrated with the apparatus <NUM> may comprise one or more conventional or available controllers. At least one of the control systems <NUM> includes a pneumatic control system as further described in <FIG> and as further defined herein. The pneumatic control system includes a safety mechanism that is configured to reversibly allow or prevent the air pressure from being supplied to the air motor <NUM> depending upon the position of the follower plate <NUM>. The control system <NUM> may also be configured to measure and/or control one or more physical system parameters, including without limitation, pressure, temperature, material flow rate, rate of compression, etc. Alternatively, the control system <NUM> is configured to control a plurality of the physical system parameters.

Still referring to <FIG>, the follower plate <NUM> is configured to fit into an open-end <NUM> of a bulk storage container <NUM>. Depending upon the state of the operation at any given time, the follower plate <NUM> may be located either outside or inside the storage container <NUM>. This storage container <NUM> may be constructed of a material capable of withstanding the forces generated during the removal of the viscous material <NUM> stored therein. The overall size of the storage container <NUM> may include any size and geometry that is commonly used or desirable for the storage of a viscous material <NUM>. The container may range in volume, without limitation from about <NUM> liters (<NUM> gallons) to about <NUM> liters (<NUM> gallons). For example, the storage container <NUM> may comprise, but not be limited to, a <NUM>-liter (<NUM>-gallon) drum, a <NUM>-liter (<NUM>-gallon) pail, a <NUM>-liter (<NUM>-gallon) can, or the like. The inner peripheral surface of the storage container is configured to interact with the follower plate <NUM> through a sealing element <NUM> in order to provide a leak-proof seal.

The sealing element <NUM> is located around the outer periphery of the follower plate <NUM> and during operation comes into contact with the inner peripheral surface of the storage container <NUM>. This sealing element <NUM> creates a leak-proof seal with the storage container when the follower plate <NUM> is located inside the storage container <NUM>. The storage container is not typically filled to capacity because the sealing element <NUM> must make contact with the container in order to form a proper seal prior to removal of the viscous material from the container <NUM>. By positioning the sealing element <NUM> around the outer periphery 32o of the follower plate <NUM>, the amount of unfilled space at the top of the storage container <NUM> can be minimized.

For the purpose of this disclosure, a viscous material <NUM> may be defined as a material that exhibits a viscosity of <NUM>,<NUM> millipascal-seconds (centipoise) or greater. Alternatively, the viscosity of the viscous material may range from about <NUM>,<NUM> millipascal-seconds (centipoise) up to about <NUM>,<NUM>,<NUM> millipascal-seconds (centipoise).

The follower plate <NUM> of the apparatus <NUM> is in fluid communication with one end of a pipe or tube <NUM> and aligned with an open end <NUM> of the storage container <NUM>. During operation, the follower plate <NUM> is moved downward into the storage container <NUM>, thereby forcing the viscous material <NUM> to flow through the pipe or tube <NUM> and pump <NUM> associated therewith. In <FIG>, the follower plate <NUM> is shown in a raised or elevated position prior to being inserted into the storage container <NUM>. In this state, pressurized air is supplied to the support cylinders <NUM> in order to cause the cylinder rods <NUM> to extend from the support cylinders <NUM> such that the crossbar <NUM> and associated pump assembly <NUM> supported thereon are raised to an elevated position. When the follower plate <NUM> is inserted into the open end <NUM> of the storage container <NUM>, pressurized air may be applied to the support cylinders <NUM> to cause the cylinder rods <NUM> to retract, and in turn cause the crossbar <NUM> to move in a downward direction. This movement (m) is depicted in <FIG> through the use of dotted lines. In this state, the follower plate <NUM> applies a force or pressure against the viscous material <NUM> in the storage container <NUM>.

The air pressure supplied from an air pressure source, such as the plant air supply, is generally pressured to about <NUM>. 9kpa (<NUM> psi) or greater; alternatively, <NUM> kpa (<NUM> psi) or more; alternatively, at least <NUM>. 7kpa (<NUM> psi); alternatively, ≥ <NUM> kpa (<NUM> psi). The air motor <NUM> increases the pressure of the air by at least <NUM> fold in order to cause the viscous material <NUM> to flow from the storage container <NUM>. Alternatively, the air motor <NUM> increases the air pressure by at least a factor of <NUM> times; alternatively, a factor that is ≥ <NUM> times; alternatively, a factor of <NUM> times or more.

The magnitude of the air pressure arising from the air motor <NUM> in the pump assembly <NUM> may be in excess of <NUM>,<NUM> kpa (<NUM> psi); alternatively, greater than <NUM>,<NUM> kpa (<NUM> psi); alternatively, at least <NUM>,<NUM> kpa (<NUM>,<NUM> psi); alternatively, <NUM>,<NUM> kpa (<NUM>,<NUM> psi) or more; alternatively from about <NUM>,<NUM> kpa (<NUM> psi) to about <NUM>,<NUM> kpa (<NUM>,<NUM> psi); alternatively, about <NUM>,<NUM> kpa (<NUM>,<NUM> psi). The applied pressure causes the viscous material <NUM> to be pumped from the storage container <NUM> into the pipe or tube <NUM> that is in fluid communication therewith. Subsequently, the viscous material <NUM> is forced to flow <NUM> through a secondary pipe or tube <NUM> to an applicator or other fluid handling equipment for ultimate application onto the surface of a part (not shown).

When desirable, the follower plate <NUM> after being inserted into the opening <NUM> of the storage container <NUM> may be heated so that the viscous material <NUM> (e.g., a hot melt adhesive, etc.) contained within the storage container <NUM> becomes liquefied or placed into a condition that allows the material <NUM> to be pumped from the storage container <NUM>. As more and more of the viscous material <NUM> is removed from the storage container <NUM>, the follower plate <NUM> continues to move (m) downward, e.g., be inserted, into the storage container <NUM> until the follower plate <NUM> reaches the bottom <NUM> of the container <NUM> as shown in <FIG> as follower plate <NUM> (dotted lines).

Once the follow plate <NUM> reaches the bottom <NUM> of the container <NUM> a change-out process is initiated in which the follower plate <NUM> is raised to its original position <NUM> as shown in <FIG>. The empty container is then removed from the stand <NUM> and a new storage container <NUM> containing viscous material <NUM> is placed on the stand <NUM>. Then, the process of forcing viscous material <NUM> to be removed from the storage container <NUM> as previously described above and further defined herein is repeated.

Referring now to <FIG>, the pneumatic control system <NUM> comprises a first valve <NUM> configured to reversibly switch between on and off in order to allow or prevent air pressure from flowing from an air supply source <NUM> (e.g., plant air supply, etc.) to the air motor <NUM>, at least one device configured to measure the position <NUM> of the follower plate relative to the storage container; and a second valve <NUM> that is in communication with the first valve <NUM> and the positioning device <NUM>. The air motor <NUM> also supplies pressurized air to operate the pump and move the follower plate <NUM>. The second valve <NUM> is configured to instruct the first valve <NUM> to prevent air pressure from being supplied from the source <NUM> to the air motor <NUM> when the follower plate is outside of the storage container and to instruct the first valve <NUM> to allow air pressure from the source <NUM> to be supplied to the air motor <NUM> when the follower plate is inside of the storage container. The first valve <NUM> may be a solenoid type valve, while the second valve <NUM> may be either an air-operated or electric pilot valve. A solenoid valve is an electromechanical device in which the solenoid uses an electric current to generate a magnetic field and thereby operate a mechanism which regulates the opening of fluid flow in the valve.

Referring now to <FIG>, a specific example of the layout of various components located within a pneumatic control system <NUM> that incorporates the safety mechanism described above and further defined herein is provided without limitation. Air pressure supplied from an air pressure source <NUM> (e.g., plant air supply, etc.) may be provided to a multiple connection points <NUM> within the tubing or pipe (e.g., series of joints, T-<NUM>, T-<NUM>,. ,T-<NUM>, etc.), which allows the air supply to be provided to different portions of the apparatus to which the pneumatic control system <NUM> interacts. For example, this air pressure <NUM> (e.g., is supplied through a first valve <NUM> to an air motor <NUM> (see pathway T-<NUM> in <FIG>). Air pressure is also supplied (see pathway T-<NUM>) to a pilot valve <NUM> that is in communication with a positioning device <NUM> that identifies the position or location of the follower plate <NUM> to be inside or outside of the storage container and to the first valve <NUM>. The positioning device <NUM> includes the use of a diverter valve <NUM> that allows air pressure to move the follower plate up or down. The pilot valve <NUM> operates the first valve <NUM> by either closing the valve <NUM> to prevent air pressure from being supplied to the air motor <NUM> or opening the valve <NUM> to allow air pressure to flow to the air motor <NUM>.

The air motor <NUM> generally includes a valve <NUM> coupled to a positive pressure pump and another solenoid valve <NUM> that alternates the air supply in valve <NUM> such that the air motor efficiently operates in an up and down manner. The air pressure is supplied through the multiple connector <NUM> (to indicate when the storage container is empty (see T-<NUM>). The pneumatic control system <NUM> may further comprise various other components, including but not limited to various valves, such as ball valves <NUM>, diverter valves <NUM>, and manual push button valves or lockouts <NUM>, as well as filters <NUM>, regulators <NUM>, switches <NUM>, and quick release or disconnections <NUM>.

According to another aspect of the present disclosure, a method <NUM> of removing the viscous material from the storage container is provided in <FIG>. Referring now to <FIG>, this method <NUM> generally comprises the steps of:.

The apparatus provided in step b) comprises an air motor-driven pump assembly, a follower plate, a sealing element, a stand, at least one controller, and a safety mechanism as previously described above. The safety mechanism reversibly allows or prevents air pressure from being supplied from the source to the air motor-driven pump assembly depending upon the position of the follower plate.

For the purpose of this disclosure the terms "about" and "substantially" are used herein with respect to measurable values and ranges due to expected variations known to those skilled in the art (e.g., limitations and variability in measurements).

For the purpose of this disclosure, the terms "at least one" and "one or more of an element are used interchangeably and may have the same meaning. These terms, which refer to the inclusion of a single element or a plurality of the elements, may also be represented by the suffix "s" at the end of the element. For example, "at least one valve", "one or more valves", and "valves" may be used interchangeably and are intended to have the same meaning.

Those skilled-in-the-art, in light of the present disclosure, will appreciate that many changes can be made in the specific embodiments which are disclosed herein and still obtain alike or similar result without departing from or exceeding the scope of the disclosure. One skilled in the art will further understand that any properties reported herein represent properties that are routinely measured and can be obtained by multiple different methods. The methods described herein represent one such method and other methods may be utilized without exceeding the scope of the present disclosure.

Within this specification, embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein.

Claim 1:
A safety mechanism (<NUM>) for use in an apparatus (<NUM>) that includes an air motor-driven pump assembly (<NUM>), a follower plate (<NUM>), a sealing element (<NUM>), a stand (<NUM>), and at least one controller, wherein the apparatus forces a viscous material (<NUM>) to flow from a storage container (<NUM>), the safety mechanism comprising:
a first valve (<NUM>) configured to reversibly switch between on and off in order to allow or prevent air pressure from flowing from a source (<NUM>) to the air motor-driven pump assembly (<NUM>);
at least one device configured to measure the position (<NUM>) of the follower plate (<NUM>) relative to the storage container (<NUM>); characterized by
a second valve (<NUM>) that is in communication with the first valve and the device; the second valve configured to instruct the first valve (<NUM>) to prevent air pressure from being supplied to the air motor-driven pump assembly (<NUM>) when the follower plate (<NUM>) is external to the storage container (<NUM>).