Suction orifice adjusting block of twin screw compressor and twin screw compressor thereof

Abstract

The application discloses a suction orifice adjusting block of a double-screw compressor and the double-screw compressor. The left side of the outer contour line of the suction orifice adjusting block comprises a curve segment AB and a circular arc segment BC, the right side comprises a curve segment FE and a circular arc segment ED, and the lower side comprises a curve segment CD. The curve segment AB and the circular arc segment BC are sequentially connected from top to bottom, the starting angle a of the end point B is 0°, the curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the starting angle a of the end point F is 0°, and the shape of the curve segment CD is the same as that of the meshing line of the long side of the female rotor tooth and the long side of the male rotor tooth. 2s The application discloses a suction orifice adjusting block of a double-screw compressor and the double-screw compressor. The left side of the outer contour line of the suction orifice adjusting block comprises a curve segment AB and a circular arc segment BC, the right side comprises a curve segment FE and a circular arc segment ED, and the lower side comprises a curve segment CD. The curve segment AB and the circular arc segment BC are sequentially connected from top to bottom, the starting angle a of the end point B is 0°, the curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the starting angle a of the end point F is 0°, and the shape of the curve segment CD is the same as that of the meshing line of the long side of the female rotor tooth and the long side of the male rotor tooth. 1s The application can eliminate the adverse effects caused by the suction orifice offset for the female and male rotors with truncated spiral portions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of screw compressors. BACKGROUND

[0002] Process screw compressors have been applied in more and more working conditions due to good power balance and less wearing parts. In order to maintain good load characteristics and reduce vibration, one of the important principles for selecting process screw compressors is that the internal and external pressure ratios must be matched.

[0003] Since there is a simple exponential relationship between the pressure ratio (Pi) and the volume ratio (Vi) and the relationship is one-to-one with the specific shape of the suction and discharge orifices on the casting, the pressure ratio matching of the process screw compressor is usually achieved by designing the corresponding shape of the discharge orifice. Generally, a newly developed model will design 2-3 kinds of discharge orifice shapes, which only correspond to 2-3 kinds of volume ratios, and cannot meet the increasingly complex application requirements of the site working conditions.

[0004] For screw compressors with fixed discharge orifice shape, there is a linear proportional relationship between the volume ratio and the rotor length, and the volume ratio of the compressor can be changed by shortening the length of the helical part (i.e. the thread segment) of the rotor pair. The prior art is to change the length of the helical part of the rotor pair to adjust the volume ratio without changing the shape of the discharge orifice, thereby widening the range of volume ratio adjustment on the existing model.

[0005] The prior art solves the problems of increasing the number of molds, long design cycle and high development cost caused by re-providing discharge orifices, but faces a technical defect that the length of the helical part of the male and female rotors is shortened from L0 to L, and correspondingly, the torsion angle of the male rotor is changed from τ0 to τ, which is linearly changed, i.e. The end position of the suction orifice determined by the torsion angle τ is offset from the existing design, thereby causing the rotor tooth space to be not fully utilized, the volume ratio to deviate from the ideal value, and the stability of the unit operation to be poor. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a suction orifice adjusting block of a twin-screw compressor, which can correct the end position of the suction orifice for the male and female rotors whose helical parts are shortened, and eliminate the adverse effects caused by the offset of the suction orifice.

[0007] The embodiment of the present application provides a suction orifice adjusting block of a double screw compressor, the double screw compressor comprising a male rotor and a female rotor, the length of the helical part of the male rotor and the female rotor being shortened; the suction orifice adjusting block is characterized in that the left side of the outer contour line of the suction orifice adjusting block comprises a curve segment AB and a circular arc segment BC, the right side of the outer contour line of the suction orifice adjusting block comprises a curve segment FE and a circular arc segment ED, and the lower side of the outer contour line of the suction orifice adjusting block comprises a curve segment CD; the curve segment AB and the circular arc segment BC are sequentially connected from top to bottom, the shape of the curve segment AB is the same as that of the short side of any tooth of the female rotor, and the shape of the circular arc segment BC is the same as that of the tooth root circle arc segment of the female rotor adjacent to the short side of any tooth of the female rotor; the starting angle a of the end point B of the curve segment AB is the included angle between the line connecting the end point B and the center of the circular arc segment BC and the line connecting the center of the circular arc segment BC and the center of the circular arc segment ED; the curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the shape of the curve segment FE is the same as that of the long side of any tooth of the male rotor, and the shape of the circular arc segment ED is the same as that of the tooth root circle arc segment of the male rotor adjacent to the long side of any tooth of the male rotor; the starting angle a of the end point F of the curve segment FE satisfies: a = 360 / (z1+z2) - a0, wherein a0 is the starting angle of the end point B of the curve segment AB. 2s is: wherein a 1s is the starting angle of the end point F of the curve segment FE, z1 is the number of teeth of the male rotor, z2 is the number of teeth of the female rotor, the starting angle of the end point B is the included angle between the line connecting the end point B and the center of the circular arc segment BC and the line connecting the center of the circular arc segment BC and the center of the circular arc segment ED; the curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the shape of the curve segment FE is the same as that of the long side of any tooth of the male rotor, and the shape of the circular arc segment ED is the same as that of the tooth root circle arc segment of the male rotor adjacent to the long side of any tooth of the male rotor; the starting angle a of the end point F of the curve segment FE satisfies: 1s wherein τ is the torsion angle of the male rotor after being shortened, a 1s0 and τ0 are respectively the suction end angle and the torsion angle of the male rotor before being shortened, and the starting angle of the end point F is the included angle between the line connecting the end point F and the center of the circular arc segment ED and the line connecting the center of the circular arc segment ED and the center of the circular arc segment BC; the curve segment CD connects the circular arc segment BC and the circular arc segment ED, and the shape of the curve segment CD is the same as that of the meshing line of the long side of the female rotor tooth and the long side of the male rotor tooth.

[0008] The embodiment of the present application also discloses a double screw compressor, comprising a suction end seat, a cylinder body, a male rotor, a female rotor and the above-mentioned suction orifice adjusting block, the suction end seat is connected with the cylinder body, the suction end seat is provided with a suction orifice penetrating in the axial direction, and the suction orifice adjusting block is detachably connected with the end face of the suction end seat facing the cylinder body; the center of the circular arc segment BC is located on the central axis of the female rotor, the center of the circular arc segment ED is located on the central axis of the male rotor, and the points D and C are located on the line connecting the axis of the female rotor and the axis of the male rotor.

[0009] The present application has at least the following advantages:

[0010] ​1. The air suction orifice adjusting block of the embodiment of the present application can ensure the accurate matching of the air suction end position of the double screw compressor and the rotor after cutting, and ensure the complete air filling of the screw rotor tooth groove and the accurate matching of the volume ratio and pressure ratio.

[0011] 2. The air suction orifice adjusting block of the embodiment of the present application avoids the extra leakage caused by the untimely closing of the air suction orifice, reduces the medium mass fluctuation in the compression cavity, thereby improving the compression efficiency and reducing the airflow pulsation. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The front view schematic diagram of the air suction orifice adjusting block according to an embodiment of the present application.

[0013] Figure 2 The side view schematic diagram of the air suction orifice adjusting block according to an embodiment of the present application is shown.

[0014] Figure 3 The schematic diagram of the meshing line of the long side of the female rotor tooth and the long side of the male rotor tooth of the double screw compressor is shown.

[0015] Figure 4 The schematic diagram of the air suction orifice adjusting block according to an embodiment of the present application installed in the air suction end seat of the double screw compressor is shown.

[0016] Figure 5 The partial structure schematic diagram of the double screw compressor equipped with the air suction orifice adjusting block according to an embodiment of the present application is shown.

[0017] Figure 6 The schematic diagram of the serialized air suction orifice adjusting block is shown. DETAILED DESCRIPTION

[0018] Please refer to Figure 1 and Figure 2 . The air suction orifice adjusting block 100 according to an embodiment of the present application is applied to the double screw compressor whose helical part of the male rotor and the female rotor is shortened, and the length of the helical part of the male rotor and the female rotor after being shortened is L (the length of the helical part of the male rotor and the female rotor before being shortened is L0). The thickness s of the air suction orifice adjusting block 100 is substantially equal to the length (L0-L) of the helical part of the male rotor and the female rotor after being shortened, and in practice, in order to reserve a certain air suction end safety gap, s is slightly smaller than (L0-L) to overcome the size change caused by the thermal expansion and cold contraction of the rotor.

[0019] As shown in Figure 1 , the left side of the outer contour line of the air suction orifice adjusting block 100 includes the curve segment AB and the circular arc segment BC, the right side of the outer contour line of the air suction orifice adjusting block 100 includes the curve segment FE and the circular arc segment ED, and the lower side of the outer contour line of the air suction orifice adjusting block includes the curve segment CD.

[0020] The curve segment AB and the circular arc segment BC are sequentially connected from top to bottom, the shape of the curve segment AB is the same as that of a short side of any tooth of the female rotor, and the shape of the circular arc segment BC is the same as that of a circular arc segment of a tooth root circle of the female rotor adjacent to the short side of any tooth of the female rotor; the starting angle a 2s is: wherein a 1s is a starting angle of an end point F of the curve segment FE, z1 is the number of teeth of the male rotor, z2 is the number of teeth of the female rotor, and the starting angle of the end point B refers to a group angle (360° minus an included angle A2 between a line BO1 of the end point B and a center O1 of the circular arc segment BC and a line O1O2 of the center O1 of the circular arc segment BC and a center O2 of the circular arc segment ED) between the line BO1 of the end point B and the center O1 of the circular arc segment BC and the line O1O2 of the center O1 of the circular arc segment BC and the center O2 of the circular arc segment ED.

[0021] The curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the shape of the curve segment FE is the same as that of a long side of any tooth of the male rotor, and the shape of the circular arc segment ED is the same as that of a circular arc segment of a tooth root circle of the male rotor adjacent to the long side of any tooth of the male rotor; the starting angle a 1s satisfies: wherein τ is a torsion angle of the male rotor after being truncated, a 1s0 and τ0 are respectively an end-of-suction angle and a torsion angle of the male rotor before being truncated, and the starting angle of the end point F refers to a group angle (360° minus an included angle A1 between a line FO2 of the end point F and a center O2 of the circular arc segment ED and a line O2O1 of the center O2 of the circular arc segment ED and a center O1 of the circular arc segment BC) between the line FO2 of the end point F and the center O2 of the circular arc segment ED and the line O2O1 of the center O2 of the circular arc segment ED and the center O1 of the circular arc segment BC.

[0022] The curve segment CD connects the circular arc segment BC and the circular arc segment ED, and the shape of the curve segment CD is the same as that of a meshing line of a long side of a tooth of the female rotor and a long side of a tooth of the male rotor. The meshing line C’D’ of the long side of the tooth of the female rotor 27 and the long side of the tooth of the male rotor 28 is as shown in Figure 3 . The meshing line C’D’ is a projection of a contact line of tooth profiles of the female rotor 27 and the male rotor 28 on a rotor axial end face. The shape of the curve segment CD is the same as that of the meshing line C’D’.

[0023] The starting angle a 2s corresponds to an end-of-suction angle of the female rotor, and the starting angle a 1s corresponds to an end-of-suction angle of the male rotor. The long side and the short side are technical terms in the art, and a complete profile is divided into a long side and a short side at a tooth root, the long side refers to a curve relatively gently changing in curvature from a tooth top to a tooth root, and the short side refers to a curve relatively greatly changing in curvature from the tooth top to the tooth root.

[0024] Optionally, the upper side of the outer contour line of the suction port adjusting block 100 comprises a circular segment IG and a circular segment GH, which are sequentially connected from left to right; the shape of the circular segment IG is the same as that of a segment of the circular tooth tip of the female rotor, and the circular segment IG has the same center as the circular segment BC; the shape of the circular segment GH is the same as that of a segment of the circular tooth tip of the male rotor, and the circular segment GH has the same center as the circular segment ED.

[0025] Optionally, the outer contour line of the suction port adjusting block 100 comprises a curved segment AI and a curved segment FH, the curved segment AI is connected between the curved segment AB and the curved segment IG, the curved segment FH is connected between the curved segment FE and the curved segment GH, and the shapes of the curved segment AI and the curved segment FH are arc-shaped. The purpose of setting the curved segment AI and the curved segment FH is to avoid the appearance of sharp corners in the suction port adjusting block 100, which are formed by rounding the sharp corners in actual manufacturing. In other embodiments, the sharp corners of the product can also be retained, in which case the upper side of the outer contour line of the suction port adjusting block 100 is composed of a circular segment AG and a circular segment GF, the shape of the circular segment AG is the same as that of a segment of the circular tooth tip of the female rotor, and the circular segment AG has the same center as the circular segment BC; the shape of the circular segment GF is the same as that of a segment of the circular tooth tip of the male rotor, and the circular segment GF has the same center as the circular segment ED.

[0026] Preferably, the ratio of the length L0 of the helical portion of the male rotor before being truncated to the diameter D0 of the helical portion of the male rotor before being truncated is in the range of L0 / D0=1.1-2.1.

[0027] Preferably, the ratio of the length L0 of the helical portion of the male rotor before being truncated to the diameter D1 of the helical portion of the male rotor after being truncated is L0=1.65*D1, and the ratio of the length L of the helical portion of the male rotor after being truncated to the diameter D1 of the helical portion of the male rotor after being truncated is L=1.1*D1.

[0028] Preferably, the ratio of the torsion angle τ of the male rotor after being truncated to the torsion angle τ0 of the male rotor before being truncated is τ≥0.625τ0.

[0029] In the present embodiment, the suction port adjusting block 100 is provided with n mounting through holes 11 extending in the thickness direction, and n≥3. In some specific embodiments, the number of the mounting through holes 11 is 5.

[0030] Please refer to Figure 4 and Figure 5In actual use, the suction port adjusting block 100 is installed on the end surface 211 of the suction end base 21 of the double-screw compressor facing the cylinder block 22. The suction end base 21 is connected with the cylinder block 22, and the suction end base 21 is provided with a plurality of axial through suction ports 210. Among them, the suction port adjusting block 100 is detachably connected with the end surface 211 of the suction end base 21 facing the cylinder block 22. In this embodiment, the suction port adjusting block 100 and the end surface of the suction end base 21 facing the cylinder block 12 are detachably connected together by a plurality of bolts, and the bolts pass through the mounting through holes 11 respectively.

[0031] The center O1 of the circular arc segment BC is located on the center axis of the female rotor (i.e., the circular arc segment BC shares the same center with the female rotor), and the radius of the circular arc segment BC is equal to the dedendum circle radius of the female rotor; the center O2 of the circular arc segment ED is located on the center axis of the male rotor (i.e., the circular arc segment ED shares the same center with the male rotor), and the radius of the circular arc segment ED is equal to the dedendum circle radius of the male rotor. The points D and C are located on the line connecting the center (center) of the female rotor and the center (center) of the male rotor.

[0032] In some specific applications, when the torsion angle τ0 of the male rotor without truncation is 300° and the suction end angle is 279°, the torsion angle τ of the truncated male rotor is 200°, and a 1s 229°. The suction port adjusting block 100 of the embodiment of the present application can also be made into products with different thicknesses, different a 1s angle sizes according to actual working condition requirements, realizing the serialization of products, such as shown in the figure, to match different suction ports of the same model to realize different volume ratios. Figure 6

[0033] The embodiment of the present application overcomes the adverse effects caused by the suction port offset due to the change of the rotor length and the torsion angle, accurately matches the suction end position with the corresponding rotor length, thereby maximizing the charging, and avoids the leakage channel between the suction port and the compression cavity, improves the operation efficiency of the unit, and improves the stability and reliability of the unit operation.​

Claims

1. A suction port adjusting block of a twin screw compressor comprising a male rotor and a female rotor, the length of the helical portion of the male and female rotors being truncated; characterized in that, The left side of the outer contour line of the suction port adjusting block comprises a curve segment AB and a circular arc segment BC, the right side of the outer contour line of the suction port adjusting block comprises a curve segment FE and a circular arc segment ED, and the lower side of the outer contour line of the suction port adjusting block comprises a curve segment CD. The curve segment AB and the circular arc segment BC are sequentially connected from top to bottom, the shape of the curve segment AB is the same as that of a short side of any tooth of the female rotor, and the shape of the circular arc segment BC is the same as that of a circular arc segment of a dedendum circle of the female rotor adjacent to the short side of any tooth of the female rotor; the starting angle a of the end point B of the curve segment AB is the included angle between a line connecting the end point B and a center of the circular arc segment BC and a line connecting the center of the circular arc segment BC and a center of the circular arc segment ED 2s is: wherein a 1s is a starting angle of an end point F of the curve segment FE, z1 is the number of teeth of the male rotor, z2 is the number of teeth of the female rotor, and the starting angle of the end point B is the included angle between a line connecting the end point B and a center of the circular arc segment BC and a line connecting the center of the circular arc segment BC and a center of the circular arc segment ED. The curve segment FE and the circular arc segment ED are sequentially connected from top to bottom, the shape of the curve segment FE is the same as that of the long side of any tooth of the male rotor, and the shape of the circular arc segment ED is the same as that of the tooth root circle arc segment of the male rotor adjacent to the long side of any tooth of the male rotor; the starting angle a of the end point F of the curve segment FE is the included angle between the line connecting the end point F and the center of the circular arc segment ED and the line connecting the center of the circular arc segment ED and the center of the circular arc segment BC. 1s satisfies: wherein, is the torsion angle of the truncated male rotor, a 1s0 and are respectively the end of inspiration angle and the torsion angle of the male rotor when it is not truncated, and the starting angle of the end point F refers to the included angle of the group angle between the line connecting the end point F and the center of the circular arc segment ED and the line connecting the center of the circular arc segment ED and the center of the circular arc segment BC. The curve segment CD connects the circular arc segment BC and the circular arc segment ED, and the shape of the curve segment CD is the same as that of the meshing line of the long side of the female rotor tooth and the long side of the male rotor tooth.

2. The suction port adjusting block of the twin screw compressor according to claim 1, wherein The upper side of the outer contour line of the suction port adjusting block comprises a circular arc segment IG and a circular arc segment GH, and the circular arc segment IG and the circular arc segment GH are sequentially connected from left to right. The shape of the circular arc segment IG is the same as that of a segment of a circular arc on the addendum circle of the female rotor tooth, and the circular arc segment IG has the same center as the circular arc segment BC. The shape of the circular arc segment GH is the same as that of a segment of a circular arc on the addendum circle of the male rotor tooth, and the circular arc segment GH has the same center as the circular arc segment ED.

3. The suction port adjusting block of the twin screw compressor according to claim 2, wherein The outer contour line of the suction port adjusting block comprises a curve segment AI and a curve segment FH, the curve segment AI is connected between the curve segment AB and the circular arc segment IG, the curve segment FH is connected between the curve segment FE and the circular arc segment GH, and the shapes of the curve segment AI and the curve segment FH are arc-shaped.

4. The suction port adjusting block of the twin screw compressor according to claim 1, wherein The ratio of the length L0 of the helical portion of the male rotor before being truncated to the diameter D0 of the helical portion of the male rotor before being truncated ranges from 1.1 to 2.

1.

5. The suction port adjusting block of the twin screw compressor according to claim 1, wherein The length L0 of the helical portion of the male rotor before being truncated and the diameter D1 of the helical portion of the male rotor after being truncated satisfy the relationship L0=1.65*D1.

6. The suction port adjusting block of the twin screw compressor according to claim 1, wherein The length L of the helical portion of the male rotor and the diameter D1 of the helical portion of the male rotor satisfy the relationship L=1.1*D1.

7. The suction port adjusting block of the twin screw compressor according to claim 1, wherein the torsion angle after the sun rotor is truncated the torsion angle when not truncated satisfies: .

8. The suction port adjusting block of the twin screw compressor according to claim 1, wherein The suction port adjusting block is provided with n mounting through holes extending in the thickness direction, and n≥3.

9. A twin screw compressor comprising a suction end housing, a cylinder block, a male rotor and a female rotor, the suction end housing being connected to the cylinder block, the suction end housing being provided with a suction port extending through in axial direction, characterized in that, The double-screw compressor comprises the suction port adjusting block according to any one of claims 1 to 8, and the suction port adjusting block is detachably connected to the end face of the suction end base facing the side of the cylinder block. The center of the circular arc segment BC is located on the central axis of the female rotor, the center of the circular arc segment ED is located on the central axis of the male rotor, and the points D and C are located on the line connecting the central axis of the female rotor and the central axis of the male rotor.

10. Twin screw compressor according to claim 9, characterized in that The suction port adjusting block and the end face of the suction end base facing the side of the cylinder block are detachably connected together through a plurality of bolts.

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