The present invention is in the field of blenders and mixers. More specifically this invention relates to high intensity blenders for mixing color pigment into materials in the plastics industry.
Standard blades for high intensity blenders are like oversized home blender blades. When mixing color pigment in using these types of blades, the pigment will often build up on the blade surface. When it builds thick enough, it will shear or flake off leaving heavily concentrated flakes of color pigment. Not only can this effect the aesthetics of the product, but it can also weaken the part due to lack of resin in that location.
A blender and blender blades are desired which would reduce the size and number of these pigment flakes, and which would be adaptable for many different applications.
A high intensity blender for mixing color pigment into plastics wherein the mixing is done by blender blades, which have a length, and a cross section perpendicular to that length, wherein the blender blades are mounted on a hub, wherein the hub is driven by a mixer motor, the improvement comprises, wherein no dimension of the cross-section is greater than ⅝ inch. A preferred embodiment has the cross section being round for the majority of the blade length, and the tip of the blade adapted to have a rectangular cross section.
Various aspects of the invention are presented in
For dry pigment, or powder, the blades work better with some form of leading edge. For these applications, according to an aspect of the invention, the blades 10 are adapted to have a flat side 40 which faces the mixer bottom 22 when the blade 10 is installed in the mixer 20. The blades 10 are further adapted to have an leading edge angled side 24 on a side opposing the flat side 40 such that the blade 10 as such adapted has a wedge shaped cross section 26. There is no need to start with a round pin to end with this cross-section, as this could be machined out of any suitable material, including flat stock. The wedge shaped cross-section 26 moves through the material being blended such that the smallest part of the wedge is the leading edge of the blade 10. This reduces friction, and in turn reduces heat. This helps reduce pigment build-up, and reduces the motor requirements.
According to a preferred embodiment of the invention, the blender blades 10 are driven by a hub 50 which is in turn driven by a mixer motor 60, wherein the blender blades 10 have an inner end 12 attachable to the hub 50, and an outer end 14 opposing the inner end 12, wherein the outer end 14 is adapted to have a flat side 40 which faces the mixer bottom 22 when the blade 10 is installed in the mixer 20, and an opposing flat side 18 which faces away from the mixer bottom 22 when the blade 10 is installed in the mixer 20.
Thus, at the blade outer end 14 where the blade is moving at higher speeds (feet per second), there is no angle for the pigment to build up on. The distance along the blade which is cut flat on both sides can be determined after use, so that it can be observed where the material builds up due to blade tip speed.
According to a preferred embodiment of the invention, the blade 10 has a flat side 40 over its length, facing the mixer bottom when installed, and an angle over the inner blade 12 top side (side facing away from the mixer bottom), and a flat on the outer blade 14 top side.
According to an aspect of the invention, the inner blade top side 12 has two angles, a leading edge angle 24, which angles away from the mixer bottom 22, and a trailing edge angle 17 which angles back towards the mixer bottom 22. A blade shaped as such may be machined from round stock or flat stock, or any other suitable material. To reduce the opportunity for pigment build-up on the blades, the leading edge angle 24 should be relatively small, in a preferred embodiment about ⅝ of an inch. If a larger blade is desired, the blade can have multiple leading edge angled 24 sections, forming a saw tooth shaped profile 80. In this embodiment, the trailing edge angles 17 may be almost perpendicular to the mixer bottom 22.
According to an aspect of the invention, the angled side 24 makes an angle 70 of approximately 30 degrees, relative to the flat side 40. This is just one possible angle as the size of the blade and its intended use factors, such as the speed at which it will be run, will affect the choice of an optimum angle.
According to a further aspect of the invention, a high intensity blender 20 for mixing color pigment into plastics, wherein the mixing is done by blender blades 10, wherein the blender blades 10 are mounted on a hub 50, wherein the hub 50 is driven by a mixer motor 60, the improvement comprising the blender blades 10 having a length 15, and a cross-section 26 perpendicular to that length 15, wherein no dimension of the cross-section 26 is greater than ½ inch.
In a preferred embodiment of the invention, no dimension of the cross-section 26 is greater than ⅜ inch.
According to an aspect of the invention, the blender blades 10 are individually removable and replaceable. This is on contrast to much of the prior art, where the blades are welded to the hub. This allows individual blades to be replaced when worn, as opposed to having to replace all of the blades. According to an aspect of the invention, the blades have a notch 80 on the end of the blade which is attached to the hub 50. Keys 82 slide into the groove 80, and are used for attachment to the hub 50. The hub 50 further has receptacles 84 for receiving the keys 82, thus attaching the blades to the hub 50.
In a further embodiment, the hub 50 comprises three separate pieces; a bottom blade disk 52, a middle spacer 54, and a top blade disk 56, wherein the bottom blade disk 52 and the top blade disk 56 are adapted for installation of blender blades 10, and wherein the middle spacer 54 is adapted to connect the top blade disk 56 to the bottom blade disk 52. The blade disks (52 and 56) can be designed to hold multiple blade quantities, such as 0, 2, 3, 4, etc. blades 10 in each disk. Thus the number of blades can be adjusted to the particular requirements. Because the blades are removable, the mixer can be easily adjusted for condition changes. For example, if an application is using three blades 10 in the top blade disk 56, and three blades 10 in the bottom blade disk 52 during normal operation, during high heat/humidity days this may be too much. Therefore, the blades 10 could be removed from the top blade disk 56 leaving the operator with three blades, and less opportunity for plate out.
To further aid in emptying out the mixers, according to an aspect of the invention, fins may be added to the hub bottom side 55.
This application claims the benefit of U.S. Provisional Application No. 60/717,805, filed Sep. 17, 2005.
Number | Date | Country | |
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60717805 | Sep 2005 | US |