This invention relates generally to blenders and, more specifically, to blenders that blend the contents therein through periodic injection of a slug of fluid into the blender.
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The concept of blending is old in the art with the art replete with various types of blenders for mixing solids or liquids. In one type of blending or mixing device paddles or agitators stir the contents of the hopper. Still other blending or mixing devices inject air into a chamber to agitate the contents of the chamber.
One type of flow mixing device for mixing solids such as dry granular materials is shown in my U.S. Pat. No. 4,944,958 wherein air is injected into a stream of dry granular materials to mix the granular materials as the mixed granular materials flows out a discharge port located at the bottom of the vessel.
Another type of device for flow mixing liquids is shown in U.S. Pat. No. 4,595,296 where as a liquid flows through a tank a bubble of air is periodically injected into the liquid at the bottom of the tank to mix the liquid as it flows through the tank and out a discharge port at the bottom of the tank.
Still another device for mixing fine grain material is shown in U.S. Pat. No. 3,097,828. In this device a plurality of nozzles are circumferentially spaced around a conical shaped head so that a gas under pressure can be directed thorough the fine grain material located in a cylindrical container. In this device, the contents of the container are churned upwards and mixed together through the sheer turbulence of the gas stream.
My U.S. Pat. No. 4,943,163 shows another type of blender for pneumatically mixing a batch of dry granular material. The invention includes a set of poppet valves that are circumferentially spaced around the bottom of the hopper with the poppet valves periodically injecting air under sufficient pressure so as to lift the batch of material off the bottom of the blender and then allow the material to drop to cause the materials to be blended together as the batch of material is repeatedly lifted and dropped.
U.S. Pat. No. 4,326,810 shows a mixing devices for powder materials where a set of nozzles are activated in a predetermined sequence to mix the powder material.
Another device for mixing granular particle materials is shown in U.S. Pat. No. 3,386,182 wherein the material in the container is fluidized by series of jets located at the bottom of the container with one of the jets having a higher velocity than the other jets.
The present invention comprises a hopper blender wherein granular or solid materials in the hopper are mixed or blended through periodic injection of a slug of fluid through a fluid port located at the bottom of the hopper. The fluid port is sealable through a slidable piston, which is cycled between a closed port condition and an open port condition. The slug of fluid is at sufficient energy so as to overcome the weight of a column of granular material located above the fluid port and at sufficient proximity to prevent backflow into the fluid port If the fluid is gas or which is lighter than the granular materials, the fluid flows upward allow the slug of gas to percolate upward through the granular materials to blend the materials in the hopper blender.
Briefly, the invention comprises a mixing apparatus including a hopper having a port piston located at least partially in a plenum chamber for periodically retracting to open a fluid port to allow a slug of gas to be quickly injected into the bottom of a hopper, which produces an in situ mixing and blending of the materials in the hopper as the slug of gas flows upward through the materials in the hopper. The port piston periodically closes to seal the fluid port without allowing the material in the hopper to backflow into the plenum chamber, which could prevent the port piston and a sealing member from being brought into sealing engagement.
A control module 18 having a fluid duct 19 connects to a fluid port 13a on one side of housing 13 for ingress and egress of an actuation fluid therethrough. Similarly, located on the other side of housing 13 is another fluid duct 13b that connects to control module 18 through fluid port 20 for ingress or egress of an actuation fluid therethrough.
Centrally located in
Located on the top portion of fluid injector 30 is an annular fluid port sealing member 32c that is supported under rigid flange 32, which has a circular port opening 32a therein for flow of a slug of pressured fluid into hopper 11.
The piston plenum chamber 45 connects to one side of the circumferential plenum chamber 14e in circumferential plenum housing 14 through a radial duct 35 and plenum duct 14d, with the ducts secured to each other through pipe connector 14g. Similarly, the opposite side of piston plenum chamber 45 connects to one side of the circumferential plenum chamber 14e in circumferential plenum housing 14 through a radial duct 36 and plenum duct 14b, with the ducts secured to each other through pipe connector 14f. Circumferential plenum chamber 14c also connects to piston plenum chamber 45 through two additional fluid ducts 14a and 14c through fluid ducts (not shown) to allow flow of fluid from plenum chamber 14e into plenum chamber 45. The use of the serial plenum chambers allows one to store a large reservoir of pressurized fluid proximate the port 32a so that a large volume of fluid i.e. a slug of fluid, can be quickly injected into the hopper 11a without concern that once introduced fluid pressure will drop occur allowing a material backflow condition to occur that can block the fluid port 32a thereby rendering the system inoperable.
Port piston 31 is part of a double piston system. As shown in
Located on one side of actuation piston 43 is a first annular actuation chamber 41 which is formed by shaft 31d and fluid injector housing wall 30a. Located on the opposite side of actuation piston 43 is a second annular actuation chamber 40, which is formed by fluid injector housing 30 and a guide rod 38. Guide rod 38 is secured to fluid injector housing bottom member 30b and extends upward into the sleeve 31c.
Actuation piston 43, which is a driver piston, is slidable in housing 13 in response to fluid actuation signals through fluid port 13a and fluid port 13b. A cylindrical compression spring 38 extends around a cylindrical extension 38 with one end of spring 38 engaging injector housing 30b and the other end engaging a shoulder 31b to maintain port piston 31 in a normal upward sealing condition even when there is no actuation pressure in actuation chambers 40 or 41 and to provide a return force to quickly return port piston 31 to the closed condition when the actuation signal is removed from chamber 41.
As can be seen in
The retraction of piston 33 from annular seat 32b allows a slug of pressurized fluid 51 in piston plenum chamber 45 to flow upward along the conical face of piston 31 and into the granular material and at the same time blow away granular material 60 away from the seat 32b. The conical face of piston causes the fluid in plenum chamber 45 to flow toward the center of the hopper rather than radially outward. The introduction of the pressurized fluid from piston plenum chamber 41 performs a dual function. First, the maintaining of a piston plenum chamber 45, which is radially fed by a larger plenum chamber 14e, allows one to rapidly deliver sufficient fluid into the materials 60 which prevents the material 60 from falling into the plenum chamber 45 as the piston 31 is retracted. Second, the flow of fluid, which in the preferred embodiment is air, scours both the seal surface 32b and the face of the conical piston 31 thus ensuring that both surfaces will be in a clean condition for resealing when the port piston 31 is brought to the up or closed condition as shown in
Thus the present invention includes the method of in situ blending, comprising placing a blendable material into hopper 11 and supplying a pressurized fluid to a piston plenum chamber 45. One periodically retracts a port piston 31 to inject a slug of fluid in the plenum chamber 45 into the hopper 11 through a fluid port 32a. Next, one closes the fluid port 31a by bring the port piston 31 into sealing engagement with the elastomer sealing member 32a while the slug of fluid is flowing therethrough to prevent backflow past the port piston 31.
To assist in preventing back flow one can include the step of resiliently biasing the port piston 31 with a spring 38 to maintain the port piston 31 in a closed condition without a pressure assistance from the actuation fluid. To ensure that sufficient fluid can be injected into the hopper a set of plenum chambers 41 and 14e are connected to each other with the more remote plenum chamber 14e being substantially larger than the piston plenum chamber 41 to ensure that fluid pressure conditions can be maintained in piston plenum chamber 41 that will prevent backflow of material therein.
In order to decrease the inertia of the port piston one can include the step of making the port piston a lightweight material such as aluminum to decrease the inertia required to change the port piston from an opening condition to a closing condition.
The method of in situ blending includes the step of injection a slug of fluid in a vertical upward direction through a single centrally located port located in the bottom of the hopper while the material is retained above the port in the hopper.
Number | Name | Date | Kind |
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2084546 | Ahlmann | Jun 1937 | A |
2618290 | Van Vliet | Nov 1952 | A |
3097828 | Groin | Jul 1963 | A |
3386182 | Lippert | Jun 1968 | A |
3647188 | Solt | Mar 1972 | A |
4325495 | Mokris | Apr 1982 | A |
4326810 | Schofield | Apr 1982 | A |
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4472062 | Balzau et al. | Sep 1984 | A |
4534653 | Coutray | Aug 1985 | A |
4595296 | Parks | Jun 1986 | A |
4943163 | Steele | Jul 1990 | A |
4944598 | Steele | Jul 1990 | A |
5693263 | Meekel et al. | Dec 1997 | A |
6629773 | Parks | Oct 2003 | B2 |
Number | Date | Country | |
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20040233776 A1 | Nov 2004 | US |