Steam screw compressor suitable for medium and high pressure working conditions

Abstract

The present invention discloses a steam screw compressor comprising a housing and a pair of screw rotors. The housing comprises an intake-end bearing seat, a cylinder block, and an exhaust-end bearing seat, which are sequentially connected. The screw rotor pair comprises a male rotor and a female rotor that mesh with each other. An intake-end bearing and an intake-end shaft seal are mounted on one end of each rotor, in sequence from the outside inward, while an exhaust-end bearing and an exhaust-end bearing are mounted on the other end of each rotor, in sequence from the outside inward. The compressor is characterized in that the gear ratio of the male rotor to the female rotor is 5:7 or 6:8. The present invention can meet steam compression requirements with an exhaust pressure greater than 1.0 MPa and an exhaust temperature greater than 200°C.

Description

Technical Field

[0001] The present invention relates to a screw compressor, in particular to a steam screw compressor. Background Art

[0002] The existing steam screw compressor has a relatively low pressure ratio, the product structure cannot withstand high pressure, and is easily deformed under high temperature conditions. It is only suitable for low-pressure and low-temperature working environments and cannot meet the demand for pressurizing low-pressure steam to obtain high-pressure steam. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a steam screw compressor that can meet the water vapor compression requirements of an exhaust pressure greater than 1.0 MPa and an exhaust temperature greater than 200°C.

[0004] According to an embodiment of the present invention, a steam screw compressor suitable for medium and high pressure working conditions includes a casing and a screw rotor pair; the casing includes an intake end bearing seat, a cylinder body and an exhaust end bearing seat connected in sequence; the screw rotor pair includes a male rotor and a female rotor that are meshed with each other; one end of each rotor is equipped with an intake end bearing and an intake end shaft seal in sequence from the outside to the inside, and the other end of each rotor is equipped with an exhaust end bearing and an exhaust end bearing in sequence from the outside to the inside; its characteristic is that the gear ratio of the male rotor to the female rotor is 5:7 or 6:8.

[0005] Furthermore, the cylinder block and the exhaust end bearing seat are integrally cast.

[0006] Furthermore, the bottom surface of the intake end bearing seat is installed with a T-shaped slider extending along the longitudinal direction of the shell and a T-shaped slider extending along the transverse direction of the shell, and the bottom surface of the exhaust end bearing seat is installed with a T-shaped slider extending along the longitudinal direction of the shell; each T-shaped slider includes a horizontal side portion and a vertical side portion, the horizontal side portion is connected to the corresponding bearing seat, and the upper end of the vertical side portion is connected to the horizontal side portion; a concave base corresponding to the T-shaped sliders installed on the intake end bearing seat and the exhaust end bearing seat is provided on the compressor support frame; the concave base includes a bottom side portion and a pair of side sides, the two ends of the bottom side portion are respectively connected to the bottom of the pair of side sides, and the bottom side portion and the pair of side sides jointly define a concave cavity; the vertical side portion of each T-shaped slider extends into the concave cavity of the corresponding concave base, and the horizontal side portion of each T-shaped slider is pressed on the top surface of the pair of side sides of the corresponding concave base.

[0007] Furthermore, the surfaces of the female rotor and the male rotor are provided with a coating.

[0008] After adopting the above technical solution, the present invention has at least the following technical effects:

[0009] 1. The gear ratio of the male rotor to the female rotor of the steam screw compressor of the embodiment of the present invention is 5:7 or 6:8. Compared with the conventional twin-screw compressor with a gear ratio of 4:6 or 5:6, the tooth thickness and tooth root diameter can be increased, thereby improving the rotor strength.

[0010] 2. The cylinder body and the exhaust end bearing seat of the steam screw compressor of the embodiment of the present invention are integrally cast, which improves the high-pressure resistance of the housing, reduces the impact of high-temperature deformation on the housing structure, and prevents leakage;

[0011] 3. The rotor surface of the steam screw compressor of the embodiment of the present invention is coated to facilitate rotor processing and control of rotor meshing clearance;

[0012] 4. Existing steam screw compressors are all fixedly mounted on the compressor support frame and cannot be moved. The steam screw compressor of this embodiment uses a T-shaped slider to cooperate with a concave base mounted on the compressor support frame, retaining the freedom of axial deformation of the shell and eliminating the influence of thermal deformation caused by high-temperature expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the appearance of a steam screw compressor according to an embodiment of the present invention is shown.

[0014] Figure 2 A bottom view schematically shows a steam screw compressor according to an embodiment of the present invention.

[0015] Figure 3 A side schematic diagram of a steam screw compressor according to an embodiment of the present invention is shown.

[0016] Figure 4 A schematic diagram of the internal structure of a steam screw compressor according to an embodiment of the present invention is shown.

[0017] Figure 5 Shown Figure 1 Schematic diagram of CC cross-section.

[0018] Figure 6 Shown Figure 5 A partially enlarged schematic diagram of part I.

[0019] Figure 7 and Figure 8 Schematic top view and schematic side view of a T-shaped slider according to an embodiment of the present invention are respectively shown.

[0020] Figure 9 and Figure 10 Schematic top view and schematic front view of a concave base according to an embodiment of the present invention are respectively shown.

[0021] Figure 11 A schematic diagram showing a first embodiment (gear ratio of 5:7) of the tooth profiles of the female and male rotors according to an embodiment of the present invention is shown.

[0022] Figure 12 A schematic diagram showing a second embodiment (gear ratio of 6:8) of the tooth profiles of the male and female rotors according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] See also Figures 1 to 10 A steam screw compressor 100 according to an embodiment of the present invention includes a housing 1 , a pair of screw rotors, and a pair of mutually meshing synchronous gears 3 .

[0025] The housing 1 includes an intake cover 11, an intake bearing seat 12, a cylinder block 13, an exhaust bearing seat 14, and an exhaust cover 15, which are connected in sequence. The intake side of the cylinder block 13 is connected to the intake bearing seat 12 via a flange, and the intake bearing seat 12 is connected to the intake cover 11 via a flange. The exhaust side of the exhaust bearing seat 14 is connected to the exhaust cover 15 via a flange. In this embodiment, the cylinder block 13 and the exhaust bearing seat 14 are integrally cast, thereby improving the high-pressure resistance of the housing 1 and reducing the impact of high-temperature deformation on the housing structure. The integrally formed components of the cylinder block 13 and the exhaust bearing seat 14 are provided with radial exhaust ports, axial exhaust ports, and radial intake ports. The intake bearing seat 12 is provided with an axial intake port.

[0026] The screw rotor pair consists of a meshing male rotor 21 and a female rotor 22. An inlet bearing 41 and an inlet shaft seal 51 are mounted on one end of each rotor, in order from the outside inward. An exhaust bearing 42 and an exhaust shaft seal 52 are mounted on the other end of each rotor, in order from the outside inward. A pair of synchronous gears 3 are mounted on the female rotor 22 and the male rotor 21, respectively, and are located outside the exhaust shaft seal 52. A motor is connected to the portion of the male rotor extending outside the casing via a coupling to drive the compressor.

[0027] See also Figure 11 and Figure 12 In this embodiment, the gear ratio of the male rotor 21 to the female rotor 22 is 5:7 or 6:8. Compared to conventional twin-screw compressors with a gear ratio of 4:6 or 5:6, this increases the tooth thickness and tooth root diameter, thereby improving rotor strength. This allows the steam compressor of this embodiment of the present invention to adapt to larger pressure ratios while maintaining high efficiency and ease of processing. A coating is applied to the surfaces of the female rotor 22 and the male rotor 21 to facilitate adjustment of the rotor meshing clearance and improve operating volumetric efficiency.

[0028] The intake end bearing 41 is an intake end radial bearing; the exhaust end bearing 42 includes an exhaust end radial bearing and an exhaust end thrust bearing ( Figure 4 In the example shown, the exhaust end radial bearing and the exhaust end thrust bearing are designed as one piece). The bearings require lubrication to operate, so lubrication holes are provided in the bearing housing.

[0029] In this embodiment, both the intake and exhaust radial bearings are sliding bearings. They are both four-lobe radial pad bearings; the exhaust thrust bearing is a tilting pad thrust bearing, thus providing a strong load-bearing capacity.

[0030] In this embodiment, the inlet end shaft seal 51 and the exhaust end shaft seal 52 are vacuum carbon ring seals or double-end dry gas seals. Specifically, the inlet end shaft seal 51 and the exhaust end shaft seal 52 use superheated steam injection on the sealing surface in combination with vacuum carbon ring seals, or vacuum on the sealing surface in combination with double-end dry gas seals. The shaft seal uses superheated steam injection on the sealing surface in combination with vacuum carbon ring seals, which can adapt to high temperatures, is non-toxic and harmless, and the leaked gas can be recycled. If vacuum on the sealing surface is combined with double-end dry gas seals, vacuuming reduces the difficulty of sealing and improves reliability. Sealing air holes and oil holes are provided on each bearing seat. In order to reduce the pressure on the sealing side, a balancing hole is also provided on the exhaust end bearing seat to connect the pressure before the exhaust side seal with the intake pressure.

[0031] In this embodiment, the steam screw compressor includes two pairs of support legs 6, each pair of support legs 6 is located on both sides of the housing 1. The upper ends of one pair of support legs 6 are respectively connected to the two sides of the intake end bearing seat 12 near the middle section of the intake end bearing seat 12 (the position of the middle section is as shown in FIG. Figure 3 As shown by the horizontal line X in the figure, the central axes of the female and male rotors are connected at a position (located on the center cross-section). The upper ends of the other pair of support legs 6 are respectively connected to the exhaust end bearing seat 14 on both sides near the center cross-section of the exhaust end bearing seat 14. The connection methods include but are not limited to integral casting, welding, bolt connection, etc. The placement of support legs in these positions can reduce the impact of thermal deformation on the housing.

[0032] In this embodiment, a T-shaped slider 7 extending along the longitudinal direction of the shell 1 (i.e., the axial direction of the female and male rotors) and two T-shaped sliders 7 extending along the transverse direction of the shell 1 are installed on the bottom surface of the intake end bearing seat 12, and a T-shaped slider 7 extending along the longitudinal direction of the shell is installed on the bottom surface of the exhaust end bearing seat 14.

[0033] Each T-shaped slider 7 includes a horizontal side portion 71 and a vertical side portion 72. The horizontal side portion 71 is provided with a plurality of first through holes 711 for bolts to pass through, so as to be connected to the corresponding bearing seat by bolts; the upper end of the vertical side portion 72 is connected to the horizontal side portion 71.

[0034] A concave base 8 is provided on the compressor support frame (not shown), corresponding one-to-one with the T-shaped sliders 7 mounted on the intake-end bearing seat 12 and the exhaust-end bearing seat 14. Concave base 8 includes a bottom portion 81 and a pair of side portions 82. The ends of bottom portion 81 are connected to the bottoms of the side portions 82. Bottom portion 81 is provided with a plurality of second through holes 811 for bolts to pass through, thereby connecting to the compressor support frame via bolts. Bottom portion 81 and the side portions 82 together define a concave cavity 83.

[0035] The vertical side 72 of each T-shaped slider 7 extends into the concave cavity 83 of the corresponding concave base 8, and the horizontal side 71 of each T-shaped slider 7 presses on the top surface of a pair of side portions 82 of the corresponding concave base 8, and the pair of side portions 82 act as guide rails.

[0036] Existing steam screw compressors are fixedly mounted on the compressor support frame and cannot be moved. The steam screw compressor of this embodiment utilizes a T-shaped slider 7 that cooperates with a concave base 8 mounted on the compressor support frame, preserving the shell's freedom of deformation and eliminating the effects of thermal expansion and deformation caused by high-temperature expansion. The exhaust-end bearing seat 14 is also restricted in its ability to deform laterally along the shell, thus serving as a positioning reference.

[0037] The steam screw compressor of this embodiment can be used for steam boosting at medium- to high-pressure conditions (1.0 MPa to 3.0 MPa). This involves using electrical power to pressurize low-pressure gaseous steam to produce high-pressure steam. Specific applications include, but are not limited to, the following industrial applications: steam boosting and transportation, closed-cycle steam heat pump systems, mechanical vapor recompression (MVR), and its application in seawater desalination, wastewater treatment, chemical distillation, and waste heat utilization.

Claims

1. A steam screw compressor suitable for medium and high pressure working conditions, comprising a housing and a screw rotor pair; the housing comprises an intake end bearing seat, a cylinder block, and an exhaust end bearing seat connected in sequence; the screw rotor pair comprises a male rotor and a female rotor meshing with each other; one end of each rotor is sequentially mounted with an intake end bearing and an intake end shaft seal from the outside to the inside, and the other end of each rotor is sequentially mounted with an exhaust end bearing and an exhaust end shaft seal from the outside to the inside; characterized in that: The gear ratio of the male rotor to the female rotor is 5:7 or 6:8; The bottom surface of the intake-end bearing seat is equipped with a T-shaped slider extending in the longitudinal direction of the shell and a T-shaped slider extending in the transverse direction of the shell. The bottom surface of the exhaust-end bearing seat is equipped with a T-shaped slider extending in the longitudinal direction of the shell. Each T-shaped slider includes a horizontal side portion and a vertical side portion. The horizontal side portion is connected to the corresponding bearing seat, and the upper end of the vertical side portion is connected to the horizontal side portion. A concave base is provided on the compressor support frame, corresponding one-to-one to the T-shaped sliders mounted on the intake end bearing seat and the exhaust end bearing seat; the concave base includes a bottom edge portion and a pair of side edges, both ends of the bottom edge portion are respectively connected to the bottoms of the pair of side edges, and the bottom edge portion and the pair of side edges jointly define a concave cavity; The vertical side of each T-shaped slider extends into the concave cavity of the corresponding concave base, and the horizontal side of each T-shaped slider presses on the top surface of a pair of side sides of the corresponding concave base.

2. The steam screw compressor according to claim 1, characterized in that The cylinder body and the exhaust end bearing seat are integrally cast.

3. The steam screw compressor according to claim 1 or 2, characterized in that: The bottom surface of the intake end bearing seat is installed with a T-shaped slider extending along the longitudinal direction of the shell and two T-shaped sliders extending along the transverse direction of the shell, and the bottom surface of the exhaust end bearing seat is installed with a T-shaped slider extending along the longitudinal direction of the shell.

4. The steam screw compressor according to claim 1 or 2, characterized in that: The steam screw compressor includes two pairs of support legs, each pair of support legs is located on both sides of the shell; The upper ends of one pair of support legs are respectively connected to the positions on both sides of the intake end bearing seat close to the middle section of the intake end bearing seat, and the upper ends of the other pair of support legs are respectively connected to the positions on both sides of the exhaust end bearing seat close to the middle section of the exhaust end bearing seat.

5. The steam screw compressor according to claim 1, characterized in that The intake end bearing is an intake end radial bearing; the exhaust end bearing includes an exhaust end radial bearing and an exhaust end thrust bearing.

6. The steam screw compressor according to claim 5, characterized in that The intake end radial bearing and the exhaust end radial bearing are both sliding bearings.

7. The steam screw compressor according to claim 5, characterized in that The radial bearing at the air inlet end and the radial bearing at the air exhaust end are both four-oil-lobe radial bearings; The exhaust end thrust bearing is a tilting pad thrust bearing.

8. The steam screw compressor according to claim 1, characterized in that The inlet end shaft seal and the exhaust end shaft seal are vacuum carbon ring seals or double end face dry gas seals.

9. The steam screw compressor according to claim 1, characterized in that The surfaces of the female rotor and the male rotor are provided with coatings.

Images