Claims:We claim,
1. An angular compounding apparatus of the present invention comprises an angular scrapping blade (1) and an angular mixing blade (2);

wherein, the angular scrapping blade (1) and the angular mixing blade (2) comprises at least one blade wing pair having two opposed wings (11, 12) and a central hub (7) having a bore there through with an inner diameter at least as large as the outer diameter of a shaft (13);

wherein each individual wings (11, 12) having a root (4) attached to a central hub (7), a first crease (8) dividing the scrapping blade (1) and the mixing blade (2) into a leading portion (5a) having a leading edge (5) and a trailing portion (6a) having a trailing edge (6a), a tip portion (3a) having a tip edge (3);

wherein the blade wings (11, 12) of the scrapping blade (1) and the mixing blade (2) are projected downwardly at an angle of 7° to 20° and preferably 10° to 15° with respect to a plane line (10) being perpendicularly extended from the axis of the central hub (7);

wherein said tip portion (3) of the angular scraping blade (1) and the angular mixing blade (2) includes a tip edge (3) provided with curvature arc R of a predetermined dimension;
wherein a leading edge (5), a trailing edge (6) and a tip edge (3) being provided with a fillet radius of predetermined dimension to avoid the sharp edges of said blades;

wherein a top surface of the tip portions (3a) of the angular mixing blade (2) is chamfered relatively shallow angle of less than 45° with the plane of respective section.

2. The angular compounding apparatus as claimed in claim 1 wherein the angular scrapping blade (1) and the angular mixing blade (2) blade is vacuumed hardened to achieve the desired hardness and the robotic tungsten carbide wear resistant coating is done to increase the wear resistance.

Dated this on 31st day of March, 2016 , Description:FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION: “An Angular Compounding Apparatus”
2. APPLICANT:

(a) Name : Neoplast Engineering Private Limited
(b) Nationality : Indian
(c) Address : M/S. Neoplast Engineering Pvt. Ltd
43, G.I.D.C Industrial Estate,
Phase-1, Vatva,
Ahmedabad-382445,
Gujarat, India.

3. PREMABLE TO THE DESCRIPTION:

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of invention

The present invention relates to an angular compounding blade apparatus and more particularly, it relates to the angular compounding apparatus comprising an angular mixing blade and an angular scrapping blade for better homogenous mixing of higher filler and dense materials like plastic compounds.

Background of invention

Generally, the mixing devices are used within a number of fields for mixing and scrapping two or more substances, such as particles or liquids or combination of these to get a desired degree of homogeneity. The compounding blades play a vital role in plastic processing and compounding industries as well as in powder mixing and dispersion application such as high speed heater mixers, high speed fluidizing mixers, turbo mixers, super mixers and high intensity mixers for mixing and scrapping of plastics and plastic suspensions. However, the performance of the plastic processing and compounding machine depends on tip speed of the mixing blade.

Currently, the flat compounding blades are used in the high speed heater mixers, high speed fluidizing mixers, turbo mixers, super mixers and high intensity mixers for mixing and scrapping of plastics and plastic suspensions.
There are disadvantages associated with the present flat compounding blades of the plastic processing and compounding machines.

The main disadvantage of conventional flat compounding blade is that the friction of blade with the compound particles increases the wear and tear of the blades which decreases the lifespan of blade. The flat wings of compounding blades in plastic processing and compounding machines also increases the period of batch time which causes more consumption of power and electricity.

In order to overcome aforesaid problems, various kinds of angular blades are developed which reduces the thrust and friction force during batch operation in plastic processing and compounding machines.

Several blades are disclosed in various patents and utility models which are described as follows.

One such angular blade for replacing the flat blades has been disclosed in US 5984520 which teaches a blade for mixing device in which the blade is formed as part of a pipe having a circular tubular cross section and thus the pipe is divided into four segments each of 90° so that the cross section of blade is a 90° circular arc and each segment which forms blade is secured to the rotor axis for a larger front portion and smaller rear portion of a blade and being parallel to the axis of the rotor.

Another such blade has been disclosed in CN 2149242, relates to turbo mixer which is an axial flow type agitator composed by the blades of the impeller in which the end face of the blade setting angle is 7°-30° and the setting angle of the root section is of the 40°-45°.

However, problem associated with prior art is that the sharp edges of the mixing blade results in poor mixing and also affects the batch time for mixing the different substances, such as particles or liquids or combination of these. Further, problem is that the casting curvature of the blades also affects in achieving the best possible mixing and also affects the final products. Due to absence of the special robotic tungsten carbide coating, the life of the blade is reduced. There have long been attempts made to change the angle of the blades and other parameters such as rotation rate, the length of the blades to optimize the mixing process.

Hence, there is an instant need to provide a streamlined angular compounding apparatus having long lifespan without increasing the period of batch time for plastic processing and compounding machines and thereby making an economic and efficient operation of plastic processing and compounding machines.
Object of the invention

The main object of the present invention is to provide an angular compounding apparatus to get homogeneous plastic compound mixtures thereby obtaining a good quality of final products in plastic processing and compounding machines.

Another object of the present invention is to provide an angular compounding apparatus that gives faster batch time for high filler and dense materials plastic processing and compounding machines.

Yet, another object of the present invention is to provide an angular compounding apparatus that reduces the period of batch time and enhances the efficiency of the system for various mixing process.

Further, object of the present invention is to provide an angular compounding apparatus that reduces the wear and tear of blade due to friction and thereby increasing the life of blade.

Further, another object of the present invention is to provide an angular compounding apparatus that is configured to utilize in high speed heater mixer, high speed fluidizing mixer, turbo mixer, super mixer and high intensity mixer.

Summary of invention

The present invention discloses an angular compounding apparatus comprising an angular scrapping blade and an angular mixing blade. The angular scrapping blade and the angular mixing blade comprises at least one blade wing pair having two opposed wings and a central hub having a bore therethrough with an inner diameter at least as large as the outer diameter of a shaft. Each individual wing comprises a root attached to a central hub, a first crease dividing the scrapping blade and the mixing blade into a leading portion having a leading edge and a trailing portion having a trailing edge, a tip portion having a tip edge. The tip portion (3) of the angular scraping blade (1) and the angular mixing blade (2) includes a tip edge (3) provided with curvature arc R of a predetermined dimension. The leading edge, the trailing edge and the tip edge is provided with a fillet radius of predetermined dimension to avoid the sharp edges of said blades.

Brief description of drawings

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.
Fig. 1 shows a perspective view of an angular compounding blade comprising an angular scrapping blade (1) and an angular mixing blade (2) according to the present invention.

Fig. 2 represents a top plan view of the angular scrapping blade (1) of the present invention.

Fig. 3 represents a front view of the angular scrapping blade (1) of the present invention.

Fig. 4 illustrates a top plan view of the angular mixing blade (2) of the present invention.

Fig. 5 shows a cross sectional view A-A of an angular mixing blade (2) according to the present invention.

Fig. 6 is a graphical representation of performance of a flat compounding blade.

Fig. 7 is a graphical representation of performance of an angular compounding blade.

Detailed description of invention

The nature of the invention and the manner in which it works is clearly described in the complete specification. The invention has various embodiments and they are clearly described in the following pages of the complete specification. Before explaining the present invention, it is to be understood that the invention is not limited in its application.

Before explaining present invention, it is to be understood that the term “Blade taper angle” refers to the angle between the plane of rotation of the blade and the slope of the blade. The term “Fillet” refers to the rounded cut to the edges i.e. leading edge, trailing edge, tip and root of the blade for avoiding sharp edges as described below. The phrase “Tip Speed” refers to the speed of blade which measures the distance traveled by the blade tip for a given amount of time. The tip speed (distance travel by tip which is an extreme point of blade) can be measured in several units i.e. revolutions per minute (RPM), meter per second (m/s), feet per minute (ft/m) etc.

Further, it is contemplated that the term “Batch time” means the amount of time required for compounding the plastics, plastic suspensions and polymers in the mixer bowl in one cycle of plastic compounding machine to obtain the desired product.

For the purpose of consistency, the terms "leading edge" and "trailing edge" as used herein are those terms associated with the rotation of the angular compounding blade in the mixing vessel. The basic design includes generally radially extending blades with a major generally chord wise body portion which may or may not be formed with a curvature.

The present invention discloses an angular compounding apparatus having angular blades which are designed with specified angles to provide homogeneous and improved mixing and thereby good quality of final products.

Now, as shown in fig. 1, the angular compounding apparatus according to present invention comprises an angular scrapping blade (1) and an angular mixing blade (2). Said angular scrapping blade (1) and angular mixing blade (2) are axially and radially mounted onto a rotatable shaft that has a flange extending radially from the shaft (13) and rotating with the shaft along the length of shaft (8) as shown in fig. 1. Said scrapping blade (1) and the mixing blade (2) are distantly mounted on said shaft (13) relative to each other.

Now as shown in fig. 2 and fig. 3, the angular scrapping blade (1) of the present invention comprises at least one blade wing pair has two opposed with wings (11) and a central hub (7) having a bore therethrough with an inner diameter at least as large as the outer diameter of the shaft (13). To form the blade wing pair, individual wings () are firmly fixed directly to the central hub (7).

The wings (11) of the angular scraping blade (1) include a blade root (4) and a tip portion (3a). Said blade root (4) is firmly fixed with the central hub (7). The blade wings (11) further includes a first crease (8) that is generally linear and extended longitudinally from the root (4) to the tip portion (3a) of the scrapping blade (1). As best shown in fig. 2, the first crease (8) of the scraping blade (1) is centrally located along a mid-width of the scraping blade (1). The first crease (8) divides the scrapping blade (1) into a leading portion (5a) and a trailing portion (6a). Said leading portion (5a) and trailing portion (6a) are deflected and oriented with respect to the first crease (8) that forms a slope at the leading portion (5a) and the trailing portion (6a). The leading portion (5a) includes a leading edge (5) and a tailing portion (6a) includes a trailing edge (6). Each tip portion (3a) of the blade wings is defined by the second crease (9) and includes a tip edge (3) being provided with curvature arc R of a predetermined dimension. The tip portions (3a) of the angular scrapping blade (1) are oriented or deflected from the second crease (9) radially in the upward direction.

The slope at the leading portion (5a) and the trailing portion (6a) reduces the thrust and friction force during the mixing and compounding process. Moreover, said leading edge (5), the trailing edge (6) and the tip edge (3) of tip portion (3a) of the scrapping blade (1) being provided with a fillet radius of predetermined dimension to avoid the sharp edges of the scrapping blade (1).

Now as shown in fig. 4 and fig. 5, the angular mixing blade (2) of the present invention comprises at least one blade wing pair has two opposed with wings (12) and a central hub (7) having a bore therethrough with an inner diameter at least as large as the outer diameter of the shaft (13). To form the blade wing pair, individual wings (13) are firmly fixed directly to the central hub (7), 180° apart.

The wings (12) of the mixing blade (2) include a blade root (4) and a tip portion (3a). Said blade root (4) is firmly fixed with the central hub (7). The blade wings (12) further includes a first crease (8) that is generally linear and extended longitudinally from the root (4) to the tip portion (3a) of the mixing blade (2). As best shown in 4, the first crease (8) is centrally located along a mid-width of the mixing blade (2). The first crease (8) divides the mixing blade (2) into a leading portion (5a) and a trailing portion (6a). Said leading portion (5a) and trailing portion (6a) are deflected and oriented with respect to the first crease (8) that forms a slope at the leading portion (5a) and the trailing portion (6a). The leading portion (5a) includes a leading edge (5) and a tailing portion (6a) includes a trailing edge (6). Each tip portion (3a) of the blade wings (12) includes a tip edge (3) being provided with curvature arc R of a predetermined dimension. The tip portions (3a) of the angular mixing blade (2) are oriented or deflected downwardly to form a chamfer (14). The top surface of said tip portions (3a) of the angular mixing blade (2) is chamfered relatively shallow angle of less than 45° with the plane of respective section.

The slope at the leading portion (5a) and the trailing portion (6a) reduces the thrust and friction force during the mixing and compounding process. Moreover, said leading edge (5), the trailing edge (6) and the tip edge (3) of tip portion (3a) of the scrapping blade (2) being provided with a fillet radius of predetermined dimension to avoid the sharp edges of the scrapping blade (1).

It should be noted that in the present embodiment of the invention, only two blade wings are used. But, practically any number of blade wings can be used for various embodiments of the present invention.

Now, as shown in fig. 3and fig. 5, said scraping blade (1) and the mixing blade (2) are projected at an angle of about from 7° to 20° and preferably 10° to 15° with respect to a plane line (10) being perpendicularly extended from the axis of centre hub (7).

Further, in order to accomplish the object of the invention, the angular compounding blades are vacuumed hardened to achieve the desired hardness. Further, a special robotic tungsten carbide wear resistant coating is done on the high friction area of the blade to reduce the wear and tear of the blade.

Due to angular design of mixing and scrapping blade according to present invention, the homogenous mixing of compounds is achieved at low tip speed. Here, thrust and friction force are transferred in the tangential direction and centrifugal force in radial direction. Thus, the resistance of this friction force causes the plastic compounds to drift against the wall of the mixture vessel from where it moves upward and this upward motion of the plastic compound produces aerating effects on the mixed particles of the plastic compounds. Thus, the shear friction between the mixed particles of the plastic compounds helps in achieving the homogenous mixtures. Thus, lower tip speed of the angular compounding blade and the reduction in period of batch time results in less power consumption and thereby makes the plastic compounding process cost effective. Due to low tip speed of the angular compounding blade, it will decrease the wear and tear of the angular compounding blade and thereby increasing the life of compounding blade.

Results:
The following results have been achieved by using the angular compounding apparatus according to present invention.

Result 1:
The following results have been achieved for angular compounding apparatus for blade taper angle of 10°.

Present invention
Batch time 7 Minutes
Total batches taken 1 Batch
Average batch time 7 Minutes
Average temperature rise/minute 10.8 °C/minute
Maximum load Amps. 43 Amps. For 25 seconds
32°C to 70°C 2 Minutes
70°C to 120°C 5 Minutes
Total batches/hour N/A
Hourly production N/A Kg.
Batch left over 50 grams
Batch left over locations N/A
Discharge time taken 32 seconds

(Table 1: Analytical data of blade taper angle 10°)
As per above experimental results, the batch time for the angular compounding blade of blade taper angle 10° is 7 minutes. Thus, the angular compounding blade of blade taper angle of 10° reduces the batch time 25%-30%.

Result 2:

The following results have been achieved for angular compounding apparatus for blade taper angle of 15°.

Present invention
Batch time 6.5 Minutes
Total batches taken 1 Batch
Average batch time 6 Minutes
Average temperature rise/minute 10.8 °C/minute
Maximum load Amps. 52 Amps. last 1 Minutes
32°C to 70°C 2 Minutes
70°C to 120°C 4.2 Minutes
Total batches/hour N/A
Hourly production Full
Batch left over 50 grams
Batch left over locations N/A
Discharge time taken 30 seconds

(Table 2: Analytical data of blade taper angle 15°)
As per above experimental results, the average batch time for the angular compounding blade of blade taper angle 15° is 6 minutes. Thus, the angular compounding blade of blade taper angle of 15° reduces the batch time 35%-40%.

The tip speed of the flat compounding blade is 27 m/s. Now, the tip speed of the angular compounding blade is 25 m/s which also 8% to 10% less than that of the flat compounding blade.

The comparative experiment has been carried out for flat compounding apparatus and for angular compounding apparatus. The analysis between the flat compounding apparatus and for angular compounding apparatus is done to check the efficiency and results for the same are discussed in below table 3:

Comparative analysis:

Flat blade Vs. angular blade comparison
Particulars Blade set Angular blade set
Batch time 9.5 minutes 6.2 minutes
Homogeneousity & Mixing quality Good Excellent
Average temperature rise/minute 8 °C/minute 10.8 °C/minute
Ambient to 70 temperature rise 3 minutes 2 minutes
70 to 120 temperature rise 6.5 minutes 4.2 minutes
Energy efficiency (only in HM) 4 units/batch 3 units/batch
Tool speed 850 RPM 800 RPM
Tip speed 27 m/s 25 m/s
VFD Hz. 42 Hz. 40 Hz.
Bottom to top blade distance 100 MM 100 MM

(Table 3: comparison of flat blade and angular blade)

Comparing the above data of both angular and scrapping blades, it is conclude that angular blades are more efficient and offer at least 35% faster batch time with lesser tool and tip speed. Less tool and tip speed will not only consume less power (kW. / Kg.), but will also decrease the wear out of blades thereby increasing the blade life by at least 50%. Energy Efficiency has also been improved by at least 20%. The angular blade set also provided excellent batch homogeneous mixing quality compound compared to old design blade which was evaluated during the PVC Pipe extrusion Trial in single screw extruder. Unlike old design blade, angular design blade increased the compound particle to particle friction rather than compound Particle to metal friction which produced excellent homogeneous mixers and faster temperature rise.

It is herein understood that although the present invention has been specifically disclosed with preferred embodiments and examples, modifications and the variations of the concept herein disclosed, may be resorted to by those skilled in the art. Such modifications and variations are considered to be within the scope of the invention and the appended claims.