US3412903A

US3412903A - Apparatus for heating and dispensing viscous materials

Info

Publication number: US3412903A
Application number: US647476A
Authority: US
Inventors: Jr William P Van Riper; Thomas A Stevens
Original assignee: Parkway Products Inc
Current assignee: Parkway Products Inc
Priority date: 1967-06-20
Filing date: 1967-06-20
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26
Also published as: GB1226390A

Description

Nov. 26, 1968 w. P. VAN RIPER, JR., ETAL 3, 03

APPARATUS FOR HEATING AND DISPENSING VISGOUS MATERIALS Filed June 20, 1967 aszmarmasmwmsrmsrwmms'- United States Patent 3,412,903 APPARATUS FOR HEATING AND DISPENSING VISCOUS MATERIALS William P. Van Riper, Jr., and Thomas A. Stevens, Cincinnati, Ohio, assignors to Parkway Products, Inc., Cincinnati, Ohio, a corporation of Ohio Filed June 20, 1967, Ser. No. 647,476 3 Claims. (Cl. 222-146) ABSTRACT OF THE DISCLOSURE Apparatus for dispensing solid or viscous material from a shipping drum or container. The material is first heated to lower the viscosity and then supplied at a lower viscosity to a reservoir from whence the liquid may enter the inlet of a pump and be dispensed from the container.

BACKGROUND OF THE INVENTION This invention relates to apparatus for dispensing solid or viscous materials from a container and, more particularly, to apparatus for dispensing heat softenable materials from drums and shipping containers.

The apparatus of this invention may be used to dispense a great variety of different materials, the only requirement being that the material have a viscosity which becomes less viscous or more easily pumpable upon a change of temperature of the material.

Specifically, the dispensing apparatus of this invention is operable to heat a localized top surface area of the material so as to convert it from a solid or an unpumpable viscous liquid to a purnpable less viscous liquid. Generally, unpumpable liquids or solids are considered to be those which have a viscosity about 100,000 centipoises. It is these unpumpable liquids or solids which this invention is primarily intended to dispense, although the inventon is equally capable of lowering the viscosity and rendering more easily pumpable those materials which are already pumpable or which have a viscosity below 100,000 centipoises at room temperature.

It is now common practice to heat materials such as grease or wax prior to pumping the material from a container. It is also common practice to heat the top surface of a material contained in a drum or container so as to enable the heated surface layer to be pumped from the container. One specific patent which discloses such apparatus is Skonberg Patent No. 3,282,469. In this patent, a heated platen attached to a follower plate is lowered into a container of viscous material so as to heat the surface of the material and enable the heated surface layer to be extracted through the pump.

The primary shortcoming of commercially available equipment is the frequency with which the pump or fluid lines become clogged because of the entry of too viscous material into the pump. It has, therefore, been the primary objective of this invention to provide an improved dispensing apparatus which is less subject to clogging.

SUMMARY OF THE INVENTION Briefly, the structure of one preferred embodiment of this invention which accomplishes these objectives comprises a stationary assembly upon which is mounted a movable assembly. The movable assembly is adapted to be lowered into a container of material and includes a follower plate having a seal or wiper around the periphery. When the movable assembly is lowered into the container, the seal engages the interior surface of the container such that the follower plate rests upon and is supported by the top surface of material contained within the drum. The movable assembly also includes a pump having an inlet tube which is located beneath the follower plate.

3,412,903 Patented Nov. 26, 1968 A heating element or platen is located beneath and spaced from the bottom surface of the follower plate and the pump inlet opening. The space between the top surface of the heating platen and the bottom of the follower plate serves as a reservoir from which low viscosity material is pumped. The material enters this reservoir through numerous small vertical apertures in the heating platen, or by passing around the periphery of the heating platen so that only previously heated low viscosity material may pass into the reservoir. Consequently, only material which has picked up a gradient of heat from the heating platen has a low enough viscosity to enter the reservoir and subsequently the pump.

These and other objectives and advantages of this invention will be more readily appreciated from the following description of the drawings in which:

FIGURE 1 is a perspective view of one preferred embodiment of a dispensing apparatus which incorporates the inventive concept of this application, and

FIGURE 2 is a cross-sectional view taken along lines 22 of FIGURE 1 illustrating the details of the pressure plate and heating platen of the dispensing apparatus.

Referring first to FIGURE 1, there is illustrated a dispensing apparatus 10 utilized to heat and dispense high viscosity material from a shipping container or drum 11. In one preferred application, the high viscosity material is a solid glue or so-called hot melt glue which converts from a solid to a viscous liquid upon the application of heat. Other unpumpable room temperature viscous materials for which this invention is particularly well suited, include conventional sealants, adhesives, resins and coating materials such as asphalt. While this invention may be used to dispense materials which are viscous liquids and thus pumpable at room temperature, it is most advantageously used to dispense unpumpable solids. which have a viscosity above 100,000 centipoises at room temperature but which, upon the application of heat, become pumpable in the sense that the materials may be dispensed through the pump without the application of relatively high pressures to force the material into the pump inlet and through the pumping system.

In one application, the hot melt glue or material 5 is solid at room temperature and must be heated to approximately 230 F. before the viscosity lowers sufficiently to enable the glue to be conveniently used as an adhesive. Some other more exotic adhesives may require that the temperature be raised-to 400 F. or even 700 F. before the material can be dispensed through the pump. If forced through the pump at lower temperatures and thus higher viscosities, the material 5 will require an i-mpractically high internal pump pressure to force flow through the pump or will clog the pump or the guns or outlets through Wll'llCh the material is subsequently directed to the application surface.

The dispensing apparatus 10 includes a base plate 15 upon which is mounted a pair of

pump elevating motors

16, 17. Each

motor

16, 17 comprises a cylinder 18, 19 rigidly attached at its bottom to the base plate 15. A piston is slidably mounted in each of the cylinders and is secured to a

piston nod

20, 21 which extends upwardly through the top of the cylinders 18, 19 respectively. A pump support plate 12 extends between and is supported from the

piston rods

20, 21 such that the plate moves vertically with the

rods

20, 21 under the control of the

motors

16, 17.

Secured to and depending from the bottom of the support plate 12 is a pump assembly, indicated generally by the numeral 22. This assembly 22 comprises a motor 23 drivingly connected to a pump tube 24 by a motor shaft 25. The pump tube \houses a conventional pumping mechanism (not shown). A plurality of vertical support rods 29 connect the pump tube 24 to the motor 25 and extend between an annular flange 28 at the top of the pump tube 24 and a bottom flange of the pump motor 23. Fluid is pumped or exhausted from the pump tube through an outlet port 31 located at the top of the tube 24.

An annular follower 32 is securied to the lower end (see FIG. 2) of the pump tube 24 so as to be vertically movable with the tube. On the periphery of the follower, a sealing and wiping element 33 is secured to the follower so as to contact the inside surface of the drum 11 and form a seal between the drum and the follower. In the preferred embodiment, the bottom surface of the follower 32 is tapered inwardly and upwardly to provide an inwardly sloping surface35. Depending from the sloping or bottom surface 35 of the follower are a plurality of spacer lugs 36 which support a depending platen or disc 37.

The platen 37 is provided with a plurality of vertical apertures 40 and a heating element 41 which is operable to raise and control the temperature of the platen and the surrounding material. It is important to note that the heating platen is spaced below the bottom surface of the follower plate and the bottom inlet 43 of the pump tube 24 so that a reservoir 44 of fluid is located between the top surface of the heating platen 37 and the pump inlet 43.

In operation, the

elevating pistons

20 and 21 are raised to their elevated position at which time a drum or shipping container 11 containing a high viscosity material, such as, for example, hot melt glue, is positioned on the base plate beneath the pump assembly 22. With the drum so positioned, the elevating pistons and 21 are lowered, thereby lowering the attached support plate 12 and pump 22 so as to locate the depending heating platen 37 on the top surface of the solid viscous material 5 contained within the drum.

The heating platen, at this time, raises the temperature of the solid material 5 so as to form an interface 46 of melted material in the area between the solid material 5 and the bottom of the heating platen 37. The liquid glue or material 5 passes upwardly through the apertures 40 and around the platen as a consequence of downward pressure on the platen 37, thereby lowering the platen into the drum. The sloping surface on the bottom of the follower in combination with the pressure applied by lowering of the follower plate may force the liquid material toward the inlet 43 of the pump tube 24 or the internal suction of the pump may pull the material into the pump from whence it is pumped through the exhaust tube 31 to an applicator gun or outlet.

Because the heating platen 37 is spaced below the follower 32, the solid or heavy viscous material within the container is prevented from entering the mouth or inlet 43 of the pump tube 24 until it has been heated to the desired viscosity. Continued lowering of the heated platen 37 toward the bottom of the drum preheats the glue or material 5 below it to a liquid which may then flow to the mouth or inlet 43 of the pump 24.

In some applications, it has been found desirable to omit the vertical apertures from the heating platen 37 so that all of the liquid material is forced to flow around the periphery of the heating platen 37 in order to enter the liquid reservoir 44 above the platen 37. This construction has the advantage of better temperature control because of the greater exposure of the material to the surface of the platen before entering the reservoir.

The primary advantage of the dispensing apparatus heretofore described results from the maintenance of a reservoir of liquid material above the top surface of the heating platen 37 and below the bottom of inlet opening 43 of the pump 22. The only way in which material may enter this reservoir is through the apertures 40 of the heating platen 37 or around the peripheral edge of the platen. The ratio of the total area of the apertures 40 or gap to the total area of the bottom surface of the heating platen 37 is dhosen to be sufficiently small in relation to the distance the material must move across the heated platen that only liquid material of the desired viscosity and temperature can flow through the apertures 40 or through the peripheral gap into the reservoir 44. Consequently, the viscosity and temperature of the material forced through the pump 24 may easily be controlled so that no solid or semi-solid material may enter and clog the pump or the dispensing apparatus.

While only a single embodiment of our invention has been illustrated and described herein, those persons skilled in the art to which this invention pertains will readily appreciate numerous changes and modifications which may be made without departing from the spirit of our invention. One such obvious modification would be to cast or form the follower platen and the heating platen as an integral unit rather than as two separate plates. Another alternative would be to utilize depending fins from the bottom of the platen to increase the heating surface of the platen and to prevent the pump entrance from contacting and sucking excessively viscous material into the pump.

Rather than pumping viscous materials in which the heating unit serves to [increase or render the material more pumpable, this invention is also useful for pumping materials which require heating of the material to trigger or initiate a chemical reaction prior to dispensing of the material. Therefore, we do not intend to be limited except by the scope of the appended claims.

Having described our invention, we claim:

1. For use in combination with a container of high viscosity material, apparatus for dispensing said material from said container comprising:

a stationary assembly,

a movable assembly carried by said stationary assembly, said movable assembly including a follower member adapted to enter the container through the top thereof,

wiper means disposed about the periphery of said follower member and adapted to engage the interior surface of the container,

a vertical aperture through said follower member, said follower member being solid and impervious to said high viscosity material from said aperture transversely outwardly to said periphery so that said follower member is operable as a piston when moved into said container,

a heating platen carried by and below said follower member, said heating platen being spaced below the bottom surface of said follower member so as to define a reservoir between the top surface of said heating platen and the bottom surface of said follower member, said heating platen having a total area in horizontal cross-section less than the total horizontal cross sectional area of said container such that said matenial can pass upwardly into said reservoir after having been heated,

a pump having an inlet tube extending downwardly through said vertical aperture of said follower member, the inlet of said inlet tube being located within said reservoir and above the top surface of said heating platen such that only material which has passed upwardly above said heating platen and into said reservoir may enter said pump inlet tube to be pumped from said container, said pump inlet tube having approximately the same transverse cross sectional area as said vertical aperture of said follower member at the point where said tube passes through said aperture,

said heating platen having a total horizontal cross sectional area less than the total combined horizontal cross sectional area of said follower member and said pump inlet so that said material may be forced into said pump inlet by downward force of said movable assembly, and

means to move said movable assembly downwardly into the container.

'2. The dispensing apparatus of claim 1 in which the bottom surface of said follower member slopes upwardly and inwardly into said pump tube inlet opening.

3. The dispensing apparatus of claim 1 in which said heating platen has a plurality of small vertical apertures therein through which said heated material may pass upwardly into said reservoir.

References Cited UNITED STATES PATENTS 2,630,248 3/1953 Hinz 222-320 X 3,031,106 4/1962 Hooker 222-146 3,178,067 4/1965 Bell et al 222146 3,282,469 11/ 1966 Skonberg 222146 ROBERT B. REEVES, Primary Examiner.

KENNETH LEIMER, Assistant Examiner.