JP-7857340-B2 - Elements for reverse-rotating twin-screw processing apparatus

JP7857340B2JP 7857340 B2JP7857340 B2JP 7857340B2JP-7857340-B2

Inventors

パドマナブハン，バブ

Assignees

スティールエンジニアリングプライベートリミテッド

Dates

Publication Date: 20260512
Application Date: 20240529
Priority Date: 20230529

Claims (16)

An element for a counter-rotating twin-screw processing apparatus, the element having an axial hole for mounting on a screw shaft of the processing apparatus, the element comprising at least one continuous self-wiping flight helically formed thereon, the element having one or more lobes having a lobe profile provided by a functionally continuous curve defined in the radial plane of the element and obtained by combining a first curve and a second curve, the first curve being expressed by a mathematical formula, the second curve being a mirror image of the first curve with respect to a radial axis passing through the central axis of the element and one of the two poles of the first curve, and the first curve being defined by the following mathematical formula. Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of the element or the lobe contour. Di is the inner diameter of the element or the lobe contour. N is the number of the one or more lobes mentioned above. α is the angle of the radial portion defined by the first curve on the radial plane.
The element according to claim 1, wherein the angle α of the radial portion varies from 0 to 2π.
The element according to claim 1, wherein the radial portion is defined by π/N.
The element according to claim 1, wherein one of the two poles of the first curve lies on the outer diameter (Do) of the element or the lobe contour.
The element according to claim 1, wherein the one or more lobes are integer lobes and the flight is an integer lobe flight.
The element according to claim 1, wherein the one or more lobes are non-integer lobes and the flight is a non-integer lobe flight.
The element according to claim 1, wherein the one or more lobes are fractional lobes and the flight is a fractional lobe flight.
The element according to claim 1, wherein the flight changes one or more times along the axial length of the element, and the change in the flight is accompanied by a change in one or more lobes along the axial length.
The element according to claim 8, wherein the flight changes from an integer lobe flight to a non-integer lobe flight, or vice versa, or from an integer lobe flight to another integer lobe flight, or from a non-integer lobe flight to another non-integer lobe flight.
The element according to claim 1, wherein the lobe contours of the one or more lobes that change spirally in the axial direction define the at least one continuous self-wiping flight.
A reverse-rotating screw for a reverse-rotating twin-screw processing apparatus having an axial hole for housing a reverse-rotating screw, wherein at least a portion of the reverse-rotating screw comprises one or more lobes having a lobe contour provided by a functionally continuous curve obtained by joining a first curve and a second curve, wherein the first curve is represented by a mathematical formula, the second curve is a mirror image of the first curve with respect to a radial axis passing through the central axis of the element and one of the two poles of the first curve, and the first curve is defined by the following mathematical formula: Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of the reverse-rotating screw or the lobe contour. Di is the inner diameter of the reverse-rotating screw or the lobe contour. N is the number of the one or more lobes mentioned above. α is the angle of the radial portion defined by the first curve on the radial plane.
The reverse-rotating screw according to claim 11, wherein at least a portion of the reverse-rotating screw defines at least one continuous self-wiping flight formed thereon in a helical manner.
A reverse-rotating twin-screw processing apparatus, A barrel defining a first cylindrical bore and a second cylindrical bore, wherein the first cylindrical bore and the second cylindrical bore intersect to form a chamber, A first shaft that rotates about an axis within the first cylindrical bore, A second shaft that rotates about an axis within the second cylindrical bore, The present invention comprises at least one element coupled to the first shaft and the second shaft, having an axial hole for attachment to the first shaft and the second shaft, and comprising a continuous self-wiping flight formed helically thereon, and comprising one or more lobes having a lobe contour defined in a radial plane and provided by a functionally continuous curve obtained by combining a first curve and a second curve, A counter-rotating twin-screw processing device wherein the first curve is represented by a mathematical formula, the second curve is a mirror image of the first curve with respect to a radial axis passing through the central axis of at least one element and one of the two poles of the first curve, and the first curve is defined by the following mathematical formula. Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of at least one element or the lobe contour. Di is the inner diameter of at least one element or the lobe contour. N is the number of the one or more lobes mentioned above. α is the angle of the radial portion defined by the first curve on the radial plane.
The reverse-rotating twin-screw processing apparatus according to claim 13, wherein the lobe contour defines the apex and the valley such that a clearance is defined between the apex of the at least one element coupled to the first shaft and the valley of the at least one element coupled to the second shaft.
The reverse-rotating twin-screw processing apparatus according to claim 13, wherein the clearance is in the range of 150 μm to 250 μm.
A pair of elements for a twin-screw processing apparatus having a first shaft and a second shaft, comprising a first element adapted to be coupled to the first shaft and a second element adapted to be coupled to the second shaft, wherein the first and second elements each have a continuous self-wiping flight helically formed thereon, and each has one or more lobes having lobe contours defined in the radial plane of the first and second elements, wherein the lobe contours are provided by a functionally continuous curve obtained by joining a first curve and a second curve, the first curve being represented by a mathematical formula, and the second curve being a mirror image of the first curve with respect to a radial axis passing through the central axis of the first or second element and one of the two poles of the first curve, and the first curve being defined by the following mathematical formula. Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of the first element, the second element, or the lobe contour. Di is the inner diameter of the first element, the second element, or the lobe contour. N is the number of the one or more lobes mentioned above. α is the angle of the radial portion defined by the first curve on the radial plane.

Description

This disclosure relates to the field of twin-screw processing devices. More specifically, this disclosure relates to elements for counter-rotating twin-screw processing devices. In the art, counter-rotating twin-screw processing devices, such as twin-screw extruders, are known to have a long barrel with two parallel holes that overlap each other. Processing elements, such as screws, mounted on two parallel shafts, are positioned within the holes. Each element has a flight formed thereon, consisting of raised portions or lobes extending along the length of the element and having a radial diameter larger than the root diameter of the element. The number of lobes may be an integer or a non-integer, forming flights of integer lobes or non-integer lobes, respectively. In a reverse-rotating twin-screw processing system, the processing elements are configured to rotate in opposite directions and are generally not self-wiping. Reverse-rotating twin-screw processing systems are used in the manufacturing, compounding, and processing of plastics, food, paints, and pharmaceuticals. The main task performed by a reverse-rotating twin-screw processing system is to mix materials and produce a molten product. There is a need to improve the material mixing capacity of the elements for reverse-rotating twin-screw processing systems and reverse-rotating processing systems. Furthermore, there is a need for elements for reverse-rotating processing systems that reduce material stagnation and improve wiping capabilities. In one aspect of the present disclosure, an element for a counter-rotating twin-screw processing apparatus having an axial hole for mounting on a screw shaft of the processing apparatus is disclosed. The element comprises at least one continuous self-wiping flight helically formed thereon. The element also comprises one or more lobes having lobe contours defined in the radial plane of the element. The lobe contour of each lobe is provided by a functionally continuous curve obtained by joining a first curve to a second curve. The first curve is expressed by a mathematical formula, and the second curve is a mirror image of the first curve with respect to the radial axis passing through the central axis of the element and one of the two poles of the first curve. The first curve is defined by the following mathematical formula: Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of the element or lobe contour. Di is the inner diameter of the element or lobe contour. N is the number of lobes. α is the angle of the radial portion defined by the first curve on the radial plane. In other embodiments of this disclosure, a reverse-rotating screw for a reverse-rotating twin-screw processing apparatus is disclosed. The reverse-rotating twin-screw processing apparatus defines an axial bore for housing the reverse-rotating screw. At least a portion of the reverse-rotating screw is provided with at least one continuous self-wiping flight helically formed thereon. The reverse-rotating screw also comprises one or more lobes having lobe contours defined in the radial plane of the reverse-rotating screw. The lobe contour of each lobe is provided by a functionally continuous curve obtained by joining a first curve to a second curve. The first curve is expressed by a mathematical formula, and the second curve is a mirror image of the first curve with respect to the radial axis passing through the central axis of the element and one of the two poles of the first curve. The first curve is defined by the following mathematical formula: Here, x and y are Cartesian coordinates defined in the radial plane. Do is the outer diameter of the element or lobe contour. Di is the inner diameter of the element or lobe contour. N is the number of lobes. α is the angle of the radial portion defined by the first curve on the radial plane. In yet another aspect of this disclosure, a counter-rotating twin-screw processing apparatus is disclosed. The counter-rotating twin-screw processing apparatus comprises a barrel defining a first cylindrical bore and a second cylindrical bore. The first and second cylindrical bore overlap to form a chamber. A first shaft rotates within the first cylindrical bore about its axis, and a second shaft rotates within the second cylindrical bore about its axis. At least one element is coupled to the first and second shafts, respectively. This element comprises axial holes for mounting to the first and second shafts, respectively. The element also comprises a continuous self-wiping flight helically formed thereon. Furthermore, the element comprises one or more lobes having lobe contours defined in the radial plane of the counter-rotating screw. The lobe contour of each lobe is provided by a functionally continuous curve obtained by coupling a first curve to a second curve. The first curve is expressed mathematically, and the second curve is a mirror image of the first curve with res