EP0267278A1

EP0267278A1 - Mixing device

Info

Publication number: EP0267278A1
Application number: EP87903770A
Authority: EP
Inventors: Richard Kennedy
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-05-13
Filing date: 1987-05-13
Publication date: 1988-05-18
Also published as: AU7510687A; JPH01500333A; CA1319679C; EP0267278A4; WO1987006852A1; US4863276A

Abstract

Dispositif mélangeur comprenant une cuvette cylindrique à extrémité ouverte (11) contenant un arbre entraîné (25) qui traverse une paroi d'extrémité (13) de la cuvette (11) pour se raccorder à un organe moteur principal (23). Des conduites (131) véhiculant des liquides amènent les liquides à mélanger jusqu'à la cuvette (11) de sorte qu'ils s'écoulent sur la paroi interne (43) de la cuvette (11) jusqu'à une extrémité de celle-ci. L'arbre entraîné (25) situé à l'intérieur de la cuvette (11) est pourvu de lames ou de dents (41) qui balaient des parties de la paroi interne (43) de la cuvette (11) en mélangeant ainsi les liquides.Mixing device comprising an open-ended cylindrical bowl (11) containing a driven shaft (25) which passes through an end wall (13) of the bowl (11) to connect to a main drive member (23). Lines (131) conveying liquids bring the liquids to be mixed up to the bowl (11) so that they flow over the internal wall (43) of the bowl (11) to one end of it this. The driven shaft (25) located inside the bowl (11) is provided with blades or teeth (41) which sweep parts of the internal wall (43) of the bowl (11) thereby mixing the liquids .

Description

MIXING DEVICE BACKGROUND OF THE INVENTION The need to provide a simple and efficient continuous mixing device for combining two or more rapidly setting up or gelling reactants is well known.

In U.S. patent No. 4,521,544 the same patentee has disclosed the concept of providing a polyurethane foam from cellulosic products. In essence the polyurethane foam can be made from waste cellulosic products such as papermill sludge, wood chips, wood particles, sawdust, waste paper or cardboard scraps. The polyurethane foam is made by reacting together a polyisocyanate, a catalyst and a cellulosic material. The subject matter in U.S. patent in 4,521,544 is incorporated herein by reference. It will be noted therefrom that the foam is made by combining two mixtures of ingredients. The first mixture is a combination of isocyanate and waste cellulosic material, which may be undehydrated papermill sludge. A flame retardant such as a borate may optionally be present in this first mixture. The second mixture is a combination of carbohydrate syrup, catalyst and optional additional water. The mixture of isocyanate may contain about 5-200 parts by weight isocyanate, about 0.1 to 2.0 parts by weight of optional surfactant, 5-75 parts by weight of optional flame retardant and 900 to 950 parts by weight of waste cellulosic material. The mixture of carbohydrate syrup may contain about 50-200 parts by weight of syrup (about 5-20% of which is water), 0.5-10 parts by weight of additional water to modify the foam properties. Any optional blowing agent must be added to the isocyanate mixture. The blowing agent may be added in quantities ranging from D..5L to 5 parts by weight.

To make the foam, the isocyanate mixture and the carbohydrate syrup mixture are thoroughly mixed together. The resulting mixture, which is liquid is then introduced into a mold, in a box for dunnage or behind a wall to form an insulating foam. While in the past expensive commercially available mixing guns have been utilized; the use has not proven to be satisfactory as the material to be mixed has a tendency to start setting up, thereby clogging the gun. The need for supplying a mixing device that does not clog is clearly an obvious need,. BRIEF DESCRIPTION OF THE INVENTION

The present invention deals and relates to an ingenious inexpensive mixing device which is designed to maintain separate the liquid reactants in a flowing manner and then to provide for the admixture thereof without the tendency of the device to set up. This is accomplished by providing for an elongated cylindrical cup which is open at its distal end and having a closed wall at its proximal end. The closed wall has a concentrical located bore therethrough. The closed wall also has two ingress ports through which the liquid components may be introduced. The cup when operated is retained at an angle to the horizontal whereby the liquid introduced components are permitted to flow downwardly along the inner wall of the cup in the direction of the distal opening.

The cup is releasably secured to a motor driven device adapted and constructed whereby a driven shaft is releasably and rotatably extended through said bore to be rotatably driven by said motor driven device. The said shaft possesses a plurality of radially extending spring steel blades having elongated portions substantially parallel with the driven shaft and the inner wall of said cup. The said blades are disposed whereby they wipe the inner cylindrical wall of said cup.

The wiping action of the rotatably driven blades effectively mix the said introduced liquids so that by the termination of the course of travel the liquid ingredients are suitably mixed. The so-mixed liquids are permitted to emanate from the said distal end of the cup in free falling stream into the retention means for the to-be-produced foamed material. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is the device of the present invention shown in operation and in association diagrammatically with constituent liquid delivery means.

Figure 2 is a cross-sectional view of the specific device of the present invention. Figure 3 is an exploded view of the mixing device of the present invention_* DETAILED DESCRIPTION OF THE INVENTION

The invention includes a cylindrical mixing cup 11 having a proximal end wall 13. ^'.The said end wall has a bore 15 and extending neck portion 17 with an external screw thread 19. the cup 11 by means of its thread 19 is releasably screwed into a female threaded portion.21 which is attached to an electric motor containing housing 23. The housing has a conventional socket arrangement common to conventional hand mixer, for instance. Thereinto and through the bore 15 is releasably positioned an elongated shaft 25 whereby said shaft is driven by the electric motor contained in said housing 23.. -A bushing 26 is supplied to seal the shaft :so -that liquid does not seep from the cup. Additional seals may be provided as needed.

The proximal end wall 13 has at least two screw fittings 27 into each of which a male fitting 29 is screwed thereinto. Each of the male fittings 29 constitutes the terminus of flexible tubings 31, each of which is adapted and constructed to carry liquids, that is, those liquids which are to be mixed in the cup 11. The component liquids are each pumped by a pump 33, each driven by an electric motor 35. The pumps may be any one of a number of specialty pumps suitable for the purpose. It has been found that a very suitable pump is a roller pump which progressively moves the to be mixed liquids through a flexible conduct which may be simply the extension of the flexible conduits fluidly connected to the cylindrical mixing cup. These pumps are also called peristalic pumps. In the embodiment shown the pump are two in number. It is contemplated within the purview of the invention that a single prime motor means could operate on two pump means through a common drive shaft, for instance. The pumps are connected at their respective exhaust sides to flexible conduits 37 to a suitable source of supply (not shown) .

The elongated shaft 25 internally of the cup 11 is suppled with four radially outwardly angularly extending portions 39 each of which terminate in distally extending blades 41 describing a configuration which permit good wiping by the radially outwardly facing portions of the blades 41 internally of the surface 43 of the cup. The blades 41 are adapted and constructed to be in wiping contact with the inner surface of the cup for their most part thereof.

Figure 3, being an exploded view of the to-be-assembled device shows another view of the arrangement with the essential parts of the device.

In operation the mixing device of the present invention has delivered through conduit 31 separately and under pressure two to-be mixed liquids. Each of the liquids is distributed into the top of the cup 11. By holding the device at a desirable and suitable angle the liquids dis¬ tribute themselves in a flowing relatively thin film pattern onto the inner surface 43 of the cup 11. As the cup 11 is open at the distal end thereof the liquids flow there out of. However, before doing so the liquids are mixed together by* the wiping and moving blades 41 attached to the rotatably driven shaft 25 through radially extending portions 39.

The mixing device of the present invention is replete with a number of advantages. For instance, the diameter of the cup and the length of the cup may be varied to accommodate a particular group of constituent. The motor that drives the shaft 28 may be of relatively low power and may be connected by means of insulated conductor 45 or may be a battery operated motor. Even an air driven motor is contemplated within the purview of the invention. Similarly, the pumps may be eliminated and the containers containing the constituents may be pumped by gaseous pressurization such as Freon.

It will be noted that benefically no valves are included or needed.

The cup is easy to clean and in fact, may be a disposable stem.

It is pointed out that while the embodiment shown is to the use of four blades or tines, the number may be smaller or larger.

Other embodiments will come to mind as the invention is contemplated all will lie within the purview of the present invention.

It should be noted that the present invention includes a number of features about which some commentary is worthwhile. For instance, by using a roller or peristalic pump arrangement, the system functions even where there is some crystallization in the lines. If the crystallization or gellation has proceeded too far, the hose lines may be simply removed from the mixing head and the peristalic pump and replaced with new lines. It will be seen that the liquids being fed may also have some entrained solids.

The respective flow rate of each of the components may be controlled by employing different diameter conduits while of course when two separately driven pumps are employed the control may be effected through a control of the speed of the respective motors.

The output may be controlled by simply providing two mixing devices, side by side which may be driven by a single motor means. While it has been stated that the system may not need valves in the conduits carrying liquids, valves may in fact be disposed near the mixing device should the device require shut down for a period of time. The valves prevention the back flow of moisture which would be deleterious to the material being pumped.

It has also been found that an electric timing means may be included in order to shut the pumps off first as desired with the mixing device being operative for 10-30 additional seconds to clear the mixing device.

It will_be possible to freshen up the catalyst, for instance, by injecting additional catalyst by venturi means from a source. The venturi is interposed in one or more of the lines supplying the mixing device.

Claims

What is claimed is:

1. A system for mixing a plurality of liquids comprising pressurization means for each of said liquids, conducting means for conveying each of said pressurized liquids to a cylindrical cup means at the upper portion thereof having a bottom, an oppositely disposed opening and an inner wall; a bore means is said bottom; driven shaft means a portion of which extends through, said bore into said cup means and a portion thereof extends externally of said bore, motive means engagably and operatively attached to said portion of said shaft which extends externally of said bore, a plurality of blades attached to said other end of said driven shaft internally of said cup adapted and constructed to wipe against the inner wall of said cup whereby said liquids are mixed when said wiping takes place and jsaid liquid is flowing against said inner wall of said cup.

2. The system of claim 1 wherein the pressurization means for each of said liquids is a pump.

3. The system of claim 2 wherein the pump for at least one conducting means is a peristaltic pump.

4. The system of claim 2 wherein the motive means is an electric motor.

5. The system of claim 1 wherein means is provided for entraining another liquid into at least one of said conduct means.

6. A device for mixing at least two liquids comprising an elongate cylinder, said cylinder having an inner wall, said cylinder having a proximal wall at one end and an opening at its other end, said proximal wall has a concentric bore therethrough, a rotatable shaft., said rotatable shaft having a portion thereof extending, through said bore for engagement to a. rotating drive means, the other portion of said rotatable shaft being positioned internally axially of said cylinder and terminating in a plurality of tines adapted and constructed to flare outwardly and radially whereby to wipe an inner wall of said cylinder whereby to mix liquids filmly flowing along said inner wall of said cylinder.