Rotating housing of a twin-screw machine

Abstract

A rotor housing for a twin-screw extruder comprises a housing body, a high-pressure orifice end face part, a female rotor cavity wall part, and a male rotor cavity wall part. The high-pressure orifice end face part, the female rotor cavity wall part, and the male rotor cavity wall part are detachably disposed in the part cavity of the housing body and together define the rotor cavity. A high-pressure axial ventilation orifice is provided on the side of the high-pressure orifice end face part. The female and male rotor cavity wall parts are non-enclosed along their circumferences, with the open side of the female rotor cavity wall part abutting the open side of the male rotor cavity wall part, and one end of the female and male rotor cavity wall parts abutting the high-pressure orifice end face part. A first and a second notch are provided at each end of the female rotor cavity wall part, respectively, and a third and a fourth notch are provided at each end of the male rotor cavity wall part, respectively. The first and third notches together constitute a high-pressure radial ventilation orifice, and the second and fourth notches together constitute a low-pressure radial ventilation orifice. The present invention achieves internal volume ratio adjustment of a twin-screw extruder at a relatively low cost.

Description

Technical Field

[0001] The present invention relates to twin-screw machinery. Background Art

[0002] The core components of a twin-screw machine (including twin-screw compressors and twin-screw expanders) are a pair of meshing rotors and the rotor housing that houses them. During meshing operation, the rotors, together with the rotor housing, form enclosed inter-tooth spaces with periodically varying volumes. Gas flows within these spaces to achieve compression or expansion. When the inter-tooth volume is greatest during intake and smallest during exhaust, this represents a volume-decreasing compression process. During this process, the rotors are driven by an electric motor or other prime mover, transferring mechanical energy to the gas, converting it into gas pressure energy. Conversely, when the inter-tooth volume is smallest during intake and greatest during exhaust, this represents a volume-increasing expansion process. The rotors are driven by high-pressure gas, which in turn drives a generator or other power machinery to convert the gas pressure energy into mechanical energy, such as a generator, which in turn converts the mechanical energy into electrical energy.

[0003] The energy conversion caused by the aforementioned rotor operation cannot be accomplished by the rotor alone; it must be enclosed within the rotor cavity of the rotor housing. Furthermore, within the specified inter-tooth volume, the rotor housing must be equipped with orifices of corresponding capacity to connect the gas within the rotor inter-tooth volume to external pipelines. Furthermore, different operating conditions (typically manifested by varying intake and exhaust pressures) require different inter-tooth volume variations. This means that the ratio of the intake and exhaust inter-tooth volumes must be adjusted based on the ratio of intake and exhaust pressures. The size of the intake and exhaust inter-tooth volumes is determined by the location of the intake and exhaust orifices.

[0004] Therefore, when the same pair of rotors are used in different working conditions, different suction and exhaust orifices need to be designed according to the working conditions. Among them, the suction orifice of the compressor or the exhaust orifice of the expander (both are when the gas pressure is lowest, hereinafter referred to as low-pressure orifices) are usually opened at the moment when the inter-tooth volume is the largest and no adjustment is required. Only the exhaust orifice of the compressor or the suction orifice of the expander (both are when the gas pressure is highest, hereinafter referred to as high-pressure orifices) need to determine different exhaust (compressor) or suction (expander) inter-tooth volumes according to different working conditions, and then determine different opening sizes, which are called different internal volume ratio (Vi) orifices in the industry. Figure 1 and Figure 2 Schematic diagrams of the front view and axonometric view of the rotor housing 100a of the existing twin-screw machine are shown respectively. Figure 1 The high-pressure axial vent opening 91 and the low-pressure axial vent opening 92 are shown in FIG. Figure 2, a high-pressure gas passage 97 communicating with the high-pressure axial vent opening 91 is shown. The rotor housing 100a has a rotor cavity. The rotor housing 100a is provided with a high-pressure axial vent opening 91 on its end surface near the high-pressure side of the rotor cavity. The inner wall surface of the rotor cavity is provided with a high-pressure radial vent opening at one end near the high-pressure side of the rotor cavity, and the inner wall surface of the rotor cavity is provided with a low-pressure radial vent opening at one end near the low-pressure side of the rotor cavity.

[0005] Figure 3 The figure shows the relationship between the inter-tooth volume of the twin-screw machine and the opening position of the high-pressure vent hole. Figure 4 The diagram schematically illustrates the installation positions of the high-pressure axial vent, the low-pressure axial vent, the high-pressure radial vent, and the low-pressure radial vent when the internal volume ratio (Vi) is 1.5 and 3, respectively. When Vi is 1.5, the installation position of the high-pressure axial vent is labeled 91a, and the installation position of the high-pressure radial vent is labeled 93a. When Vi is 3, the installation positions of the high-pressure axial vent and the high-pressure radial vent are labeled 91b, and 93b, respectively. The installation positions of the low-pressure axial vent and the low-pressure radial vent remain unchanged when Vi is 1.5 and 3, and are labeled 92a and 94a, respectively.

[0006] Typically, a rotor housing part (usually a casting, but sometimes welded) corresponds to one orifice with a specific volume ratio. Once the orifice design is complete, the rotor housing part is finalized. If a project requires orifices with multiple volume ratios, the manufacturer must produce multiple rotor housings. This undoubtedly significantly increases design, production, and storage costs. This impact is particularly significant for castings, as casting molds are very expensive and production cycles are lengthy. On the other hand, forcing the use of a rotor housing with an inappropriate orifice will cause the compressor or expander to operate under inappropriate conditions, resulting in significant energy waste, increased vibration and noise, and a reduced lifespan. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a modular rotor housing, which can achieve the adjustment of the internal volume ratio of a twin-screw machine at a relatively low cost and can improve the product precision.

[0008] A rotor shell of a twin-screw machine according to an embodiment of the present invention comprises a rotor shell having a rotor cavity, the rotor cavity comprising a female rotor cavity and a male rotor cavity; the rotor shell is provided with a high-pressure axial ventilation hole on the end face close to the high-pressure side of the rotor cavity, the inner wall surface of the rotor cavity is provided with a high-pressure radial ventilation hole at one end close to the high-pressure side of the rotor cavity, and the inner wall surface of the rotor cavity is provided with a low-pressure radial ventilation hole at one end close to the low-pressure side of the rotor cavity; its characteristic is that the rotor shell comprises a shell body, a high-pressure hole end face part, a female rotor cavity wall part and a male rotor cavity wall part; the shell body has a part cavity, the high-pressure hole end face part, the female rotor cavity wall part and the male rotor cavity wall part are respectively detachably arranged in the part cavity; the high-pressure hole end face part is provided with a female rotor shaft hole and a male rotor shaft hole that penetrate the high-pressure hole end face part in the thickness direction, and the high-pressure axial ventilation hole is provided. The air orifice is arranged on the side of the high-pressure orifice end face part; the female rotor cavity wall part and the male rotor cavity wall part are both in a non-closed shape with an opening along their circumference, the open side of the female rotor cavity wall part abuts the open side of the male rotor cavity wall part, one end of the female rotor cavity wall part and one end of the male rotor cavity wall part abut against the high-pressure orifice end face part respectively, and the high-pressure orifice end face part, the female rotor cavity wall part, the male rotor cavity wall part and the shell body jointly define the rotor cavity; one end of the female rotor cavity wall part is provided with a first notch, the other end of the female rotor cavity wall part is provided with a second notch, one end of the male rotor cavity wall part is provided with a third notch, and the other end of the male rotor cavity wall part is provided with a fourth notch, the first notch and the third notch together constitute a high-pressure radial ventilation orifice, and the second notch and the fourth notch together constitute a low-pressure radial ventilation orifice.

[0009] The present invention has at least the following advantages and features:

[0010] 1. The rotor housing of the embodiment of the present invention maintains a uniform body, and the portion of the rotor housing that affects the internal volume ratio is made into modular, detachable parts. To meet different internal volume ratio requirements, the housing body does not need to be modified; only modular parts with different orifice sizes need to be produced, thereby significantly reducing production costs and achieving low-cost adjustment of the internal volume ratio of the twin-screw extruder.

[0011] 2. The high-pressure orifice end face, female rotor cavity wall, and male rotor cavity wall components of the embodiments of the present invention are modularized as independent parts and can be machined using CNC machine tools. However, these components, which affect the internal volume ratio, are typically part of the rotor housing casting in the prior art. Their machining accuracy is largely dependent on casting accuracy. Machining accuracy is far superior to casting accuracy, so the rotor housing of the embodiments of the present invention achieves improved accuracy compared to the prior art's integrally cast rotor housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 and Figure 2A front view schematic diagram and an axonometric schematic diagram of the rotor housing of an existing twin-screw machine are respectively shown.

[0013] Figure 3 A schematic diagram showing the relationship between the inter-tooth volume of a twin-screw machine and the installation position of the high-pressure vent orifice is shown.

[0014] Figure 4 A schematic diagram of the installation positions of the high-pressure axial vent opening, the low-pressure axial vent opening, the low-pressure axial vent opening, and the low-pressure radial vent opening under different internal volume ratios (Vi) is shown.

[0015] Figure 5 and Figure 6 A schematic front view and a schematic cross-sectional view (looking from below) of a rotor housing of a twin-screw machine according to an embodiment of the present invention are respectively shown.

[0016] Figure 7 and Figure 8 A front view schematic diagram and an axonometric schematic diagram of a housing body according to an embodiment of the present invention are respectively shown.

[0017] Figure 9 、 Figure 10 and Figure 11 A three-dimensional schematic diagram, a front view schematic diagram and a left view schematic diagram of a high-pressure orifice end face component according to an embodiment of the present invention are respectively shown.

[0018] Figures 12 to 15 The three-dimensional schematic diagram, front view schematic diagram, right view schematic diagram and top view schematic diagram of the female rotor cavity wall part according to an embodiment of the present invention are respectively shown.

[0019] Figures 16 to 19 The three-dimensional schematic diagram, front view schematic diagram, left view schematic diagram and top view schematic diagram of the male rotor cavity wall component according to an embodiment of the present invention are respectively shown. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] See also Figures 5 to 19 The rotor housing 100 of a twin-screw machine according to an embodiment of the present invention includes a housing body 1 , a high-pressure port end surface component 2 , a female rotor cavity wall component 3 , and a male rotor cavity wall component 4 .

[0022] The shell body 1 has a parts cavity 10 , in which the high-pressure port end face part 1 , the female rotor cavity wall part 3 and the male rotor cavity wall part 4 are respectively detachably arranged.

[0023] The high-pressure orifice end face part 2 is provided with a female rotor shaft hole 21 and a male rotor shaft hole 22 which pass through the high-pressure orifice end face part along the thickness direction. A high-pressure axial ventilation hole 20 is provided on the side of the high-pressure orifice end face part 2. The female rotor cavity wall part 3 and the male rotor cavity wall part 4 are both non-closed with openings along their circumference. The open side of the female rotor cavity wall part 3 abuts against the open side of the male rotor cavity wall part 4. One end of the female rotor cavity wall part 3 and one end of the male rotor cavity wall part 4 respectively abut against the high-pressure orifice end face part 2. The high-pressure orifice end face part 2, the female rotor cavity wall part 3, the male rotor cavity wall part 4 and the shell body 1 jointly define the rotor cavity 11 of the rotor shell. The rotor cavity 11 includes a female rotor cavity 13 and a male rotor cavity 14. The female rotor cavity 13 and the male rotor cavity 14 are respectively used to accommodate the female rotor and the male rotor of the twin-screw machine.

[0024] A first notch 31 is provided at one end of the female rotor cavity wall part 3, a second notch 32 is provided at the other end of the female rotor cavity wall part 3, a third notch 43 is provided at one end of the male rotor cavity wall part 4, and a fourth notch 44 is provided at the other end of the male rotor cavity wall part. The first notch 31 and the third notch 43 together constitute a high-pressure radial ventilation opening 23, and the second notch 32 and the fourth notch 44 together constitute a low-pressure radial ventilation opening 24.

[0025] The contours of the aforementioned rotor cavity 11, high-pressure axial vent opening 20, high-pressure radial vent opening 23, and low-pressure radial vent opening 24 are all consistent with the prior art. The cross-sectional profile of the first notch 31 and second notch 32 of the female rotor cavity wall component 3 is consistent with the helical line of the female rotor, and the cross-sectional profile of the third notch 43 and fourth notch 44 of the male rotor cavity wall component 4 is consistent with the helical line of the male rotor. For twin-screw extruders, the angles and sizes of the high-pressure axial vent opening, high-pressure radial vent opening, and low-pressure radial vent opening are set based on actual operating conditions and the preset internal volume ratio. Accordingly, the angles and sizes of the first to fourth notches are also set based on actual operating conditions and the preset internal volume ratio.

[0026] In the case where the twin-screw machine is a twin-screw compressor, the rotor housing 100 of this embodiment plays the role of the rotor cylinder and the exhaust end seat, the aforementioned high-pressure axial vent port 20 is the axial exhaust port of the twin-screw compressor, the aforementioned high-pressure radial vent port is the radial exhaust port of the twin-screw compressor, and the aforementioned low-pressure radial vent port is the radial intake port of the twin-screw compressor.

[0027] In the case where the twin-screw machine is a twin-screw expander, the rotor housing 100 of this embodiment plays the role of the rotor cylinder and the suction end seat, the aforementioned high-pressure axial vent port 20 is the axial suction port of the twin-screw expander, the aforementioned high-pressure radial vent port is the radial suction port of the twin-screw expander, and the aforementioned low-pressure radial vent port is the radial exhaust port of the twin-screw expander.

[0028] The high-pressure orifice end face part 2, the female rotor cavity wall part 3 and the male rotor cavity wall part 4 can be detachably arranged in the part cavity 10 through a variety of different installation methods. In a specific embodiment, the end face of one end of the high-pressure orifice end face part 2 abuts against the step surface 101 set on the inner wall of the part cavity 10, and the end face of the other end abuts against one end of the female rotor cavity wall part 3 and the male rotor cavity wall part 4 respectively, and the other end of the female rotor cavity wall part 3 and the other end of the male rotor cavity wall part 4 abut against the suction end seat of the twin-screw compressor or the exhaust end seat of the twin-screw expander, thereby fixing the high-pressure orifice end face part 2, the female rotor cavity wall part 3 and the male rotor cavity wall part 4 in the part cavity 10. In other embodiments, the high-pressure orifice end face part 2, the female rotor cavity wall part 3 and the male rotor cavity wall part 4 can also be connected to the shell body 1 by a tenon connection or detachably connected together by fasteners.

[0029] In this embodiment, the female rotor cavity wall component 3 and the male rotor cavity wall component 4 are C-shaped and inverted C-shaped, respectively. The first notch 31 is adjacent to the third notch 43, and the second notch 32 and the fourth notch 44 are separated from each other by the main body of the female rotor cavity wall component 3 and the main body of the male rotor cavity wall component 4.

[0030] In a specific embodiment, the rotor housing 100 of the embodiment of the present invention can be obtained by machining on the basis of the existing rotor housing 100a. The specific machining method is as follows:

[0031] The first step is to replace the existing rotor housing 100 (such as Figure 1 and Figure 2 (as shown) is changed to a standardized housing body 1. The female and male rotor cavities of the existing rotor housing 100 are bored larger and deeper. Assume that the male rotor cavity diameter of the original rotor housing 100 is D1, the female rotor cavity diameter is D2, and the depths of both the female and male rotor cavities are L. The adjusted male rotor cavity (i.e., the male rotor side portion of the aforementioned component cavity) has a diameter of D1n, the female rotor cavity (i.e., the female rotor side portion of the aforementioned component cavity) has a diameter of D2n, and the depths of both the female and male rotor cavities are Ln. These dimensions satisfy the following relationship:

[0032] D1n=a*D1, a is taken as 1.15~1.5;

[0033] D2n=b*D2, b is 1.15~1.5;

[0034] Ln=c*L, c is 1.15~1.5;

[0035] The second step is to process the high-pressure orifice end face part 2, whose thickness is equal to Ln-L. A high-pressure axial vent hole is opened on its side;

[0036] The third step is to process the female rotor cavity wall part 3, whose thickness is equal to (D2n-D2) / 2. The first notch and the second notch are respectively opened at both ends.

[0037] Step 4: Process the male rotor cavity wall part 4, whose thickness is equal to (D1n-D1) / 2. The third and fourth notches are respectively opened at its two ends;

[0038] Step 5: Assemble the above three parts according to the assembly drawing (such as Figure 6 as shown) to install it.

[0039] According to the embodiment of the present invention, the shell body of the rotor shell remains unified, and the part of the rotor shell that affects the internal volume ratio is made into a modular and detachable part. For different internal volume ratio requirements, there is no need to change the shell body. It is only necessary to produce high-pressure orifice end face parts, female rotor cavity wall parts and male rotor cavity wall parts with different orifice sizes to meet the above requirements, thereby greatly reducing production costs.

Claims

1. A rotor housing for a twin-screw extruder, the rotor housing having a rotor cavity, the rotor cavity including a female rotor cavity and a male rotor cavity; the rotor housing having a high-pressure axial vent opening on an end surface close to the high-pressure side of the rotor cavity, a high-pressure radial vent opening on an inner wall surface close to the high-pressure side of the rotor cavity, and a low-pressure radial vent opening on an inner wall surface close to the low-pressure side of the rotor cavity; characterized in that: The rotor housing includes a housing body, a high-pressure port end face part, a female rotor cavity wall part, and a male rotor cavity wall part; The housing body has a parts cavity, and the high-pressure port end surface parts, the female rotor cavity wall parts and the male rotor cavity wall parts are respectively detachably arranged in the parts cavity; The high-pressure orifice end face part is provided with a female rotor shaft hole and a male rotor shaft hole which penetrate the high-pressure orifice end face part in the thickness direction, and the high-pressure axial ventilation hole is provided on the side of the high-pressure orifice end face part; the female rotor cavity wall part and the male rotor cavity wall part are both in a non-closed shape with an opening along their circumference, and the female rotor cavity wall part and the male rotor cavity wall part are respectively C-shaped and inverted C-shaped, and the opening side of the female rotor cavity wall part abuts against the opening side of the male rotor cavity wall part, and one end of the female rotor cavity wall part and one end of the male rotor cavity wall part abut against The high-pressure orifice end face part, the high-pressure orifice end face part, the female rotor cavity wall part, the male rotor cavity wall part and the shell body jointly define the rotor cavity; one end of the female rotor cavity wall part is provided with a first notch, the other end of the female rotor cavity wall part is provided with a second notch, one end of the male rotor cavity wall part is provided with a third notch, the other end of the male rotor cavity wall part is provided with a fourth notch, the first notch and the third notch together constitute the high-pressure radial ventilation orifice, and the second notch and the fourth notch together constitute the low-pressure radial ventilation orifice.

2. The rotor housing according to claim 1, wherein: The first notch is adjacent to the third notch; The second notch and the fourth notch are separated from each other.

3. The rotor housing according to claim 1, wherein: The inner wall of the part cavity is provided with a step surface, the end surface of one end of the high-pressure orifice end surface part abuts against the step surface, and the end surface of the other end abuts against the female rotor cavity wall part and the male rotor cavity wall part respectively.

4. The rotor housing according to claim 1, wherein The twin-screw machine is a twin-screw compressor, the high-pressure axial vent opening is an axial exhaust opening, the high-pressure radial vent opening is a radial exhaust opening, and the low-pressure radial vent opening is a radial intake opening.

5. The rotor housing according to claim 1, wherein: The twin-screw machine is a twin-screw expander; the high-pressure axial vent opening is an axial air intake opening, the high-pressure radial vent opening is a radial air intake opening, and the low-pressure radial vent opening is a radial air exhaust opening.

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