Sealing structure of turbo expander

Abstract

According to the sealing structure of the turbo expander, the diameter of an inlet of a left impeller is D11, the diameter of an outlet of the left impeller is D21, the diameter of an inlet of a right impeller is D12, and the diameters of an outlet of the right impeller are D22 and D11gt; d12, D21lt; d22; the impeller flow guide cover plate is inserted into an inlet end groove of the air outlet pipe, the impeller flow guide cover plate and the air outlet pipe form an impeller end radial sealing structure, the impeller upper cover plate is inserted into an impeller flow guide cover plate annular groove, the impeller upper cover plate and the impeller flow guide cover plate form an impeller end axial sealing structure, a hub sealing wedge is arranged on the radial outer side of the hub, and a movable ring sealing wedge is arranged on the radial inner side of the movable ring. And the hub sealing wedge and the moving ring sealing wedge form a sealing structure. As the sealing structure of the turbo expander is improved, the leakage amount is reduced, the sealing performance is enhanced, and the adaptability and the production efficiency are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical seals, and in particular to a sealing structure of a turbine expander. Background Art

[0002] At present, the energy structure of most countries in the world has shifted to oil and gas, while my country is one of the few countries that uses coal as its main energy source. The recovery and full utilization of low-grade thermal energy can not only effectively alleviate the continuous consumption of high-grade energy resources to a certain extent, but also reduce pollution emissions and protect the ecological environment. An important reason for the low energy utilization rate in my country is that low-temperature waste heat energy has not been fully utilized. The temperature of this part of energy is usually less than 250℃ but greater than 80℃, including industrial waste heat such as waste steam, waste hot water, and waste flue gas, as well as new energy sources such as solar energy, geothermal energy, and ocean temperature difference energy. Therefore, how to reasonably utilize low-temperature waste heat resources, expand the temperature difference range of low-temperature waste heat gradients, and use a variety of methods to achieve efficient utilization of low-temperature waste heat resources has become an urgent problem to be solved. Converting low-grade thermal energy into higher-grade electrical energy is the most common, direct and effective way to utilize low-temperature waste heat today. ORC power generation technology is a common technology for recovering low-temperature waste heat. The equipment required for the entire system mainly includes ORC expansion generator sets, evaporators, condensers and working fluid pumps. The most important equipment is the expander of the ORC generator set.

[0003] Prior art CN106593547A discloses a sealing system for a turbine expander, which comprises an inner bearing on the expander side and an outer bearing on the supercharger side, wherein an expansion end sealer and a supercharging end sealer are respectively arranged on the outer sides of the inner bearing and the outer bearing, through which a dry sealer body can be passed into the shaft seal, and the expansion end sealer and the supercharging end sealer are respectively connected to the instrument gas main pipe through their own sealer pipelines; a check valve and a precision pressure reducing valve for preventing gas backflow are connected in series in the sealer pipeline connected to the expansion end sealer; a check valve and a pipeline stop valve for preventing gas backflow are also connected in series in the sealer pipeline connected to the supercharging end sealer; and a main pipe stop valve is also connected in series on the instrument gas main pipe; it has the characteristics of reasonable structural composition, convenient and reliable use, and the mechanical device and the instrument work together to achieve a better sealing effect.

[0004] However, the above-mentioned turbine expander has design limitations, such as weak adaptability, poor sealing effect, large gas leakage, and affecting production efficiency. Therefore, in response to these problems, the applicant proposes a sealing structure of a turbine expander to solve the above-mentioned problems so as to reduce leakage, enhance sealing, and thereby improve adaptability and production efficiency. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings in the prior art and to propose a sealing structure for a turbine expander.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A sealing structure for a turboexpander. The turboexpander includes a generator, a left turboexpander, and a right turboexpander; the left turboexpander and the right turboexpander are respectively arranged on the left and right sides of the generator; and it is characterized in that: there are differences in size between the left turboexpander and the right turboexpander; the left turboexpander includes a left bearing, a left sealing structure, a left impeller, a left volute, and a left rotor shaft. A left air inlet and a left air outlet are arranged on the left volute. The left impeller is installed on the left rotor shaft. The right turboexpander includes a right bearing, a right sealing structure, a right impeller, a right volute, and a right rotor shaft. A right air inlet and a right air outlet are arranged on the right volute. The right impeller is installed on the right rotor shaft; where the inlet diameter of the left impeller is D11, the outlet diameter of the left impeller is D21, the inlet diameter of the right impeller is D12, and the outlet diameter of the right impeller is D22, D11>D12, D21<D22; the turboexpander also includes an outlet pipe, a nozzle cover plate, a nozzle pressure plate, a nozzle, and an impeller guide cover plate. The sealing structures of the left turboexpander and the right turboexpander both include a volute sealing cover plate and a nozzle sealing cover plate; the outlet pipe has an outlet pipe inlet end groove at the inlet end. The impeller guide cover plate is inserted into the outlet pipe inlet end groove and forms an impeller end radial sealing structure with the outlet pipe. The radial wall surface of the outlet pipe inlet end groove is evenly distributed with outlet pipe conical sealing rings, and the radial end surface on the outlet side of the impeller guide cover plate is evenly distributed with impeller guide cover plate circular sealing rings. The outlet pipe conical sealing rings and the impeller guide cover plate circular sealing rings are arranged alternately. The outlet pipe is provided with an outlet pipe sealing pressurizing channel. One end of the outlet pipe sealing pressurizing channel communicates with the impeller end radial sealing structure, and the other end communicates with a high-pressure gas cylinder; the impeller guide cover plate has an impeller guide cover plate ring groove on the radial inner side of the end. The impeller upper cover plate is inserted into the impeller guide cover plate ring groove and forms an impeller end axial sealing structure with the impeller guide cover plate. The inner side wall of the air outlet end of the impeller upper cover plate is provided with inner small blades of the impeller upper cover plate, and the end wall of the air outlet end of the impeller upper cover plate is provided with front guide small blades of the impeller upper cover plate. Both the inner small blades of the impeller upper cover plate and the front guide small blades of the impeller upper cover plate have gaps with the impeller guide cover plate ring groove. The impeller guide cover plate is provided with an impeller sealing pressurizing channel. One end of the impeller sealing pressurizing channel communicates with the impeller end axial sealing structure, and the other end communicates with a high-pressure gas cylinder; the sealing structure also includes a shaft side sealing structure, and the shaft side sealing structure adopts a dynamic ring and static ring sealing structure.

[0008] Further, the static ring is connected to the volute sealing cover plate, and the dynamic ring is connected to the rotor shaft.

[0009] Further, the side of the static ring close to the dynamic ring is provided with a static ring inner sealing groove, and the static ring inner sealing groove is provided with a dynamic and static sealing spring. One end of the dynamic and static sealing spring is fixed in the static ring inner sealing groove, and the other end is movably connected to the dynamic ring.

[0010] Furthermore, the impeller lower cover plate is provided with an impeller lower cover plate sealing ring, the side of the static ring close to the impeller is provided with a static ring outer sealing groove, and the end of the impeller lower cover plate sealing ring is arranged in the static ring outer sealing groove to form a sealing structure.

[0011] Furthermore, the impeller hub is connected to the rotor shaft through stud bolts, a hub sealing wedge is provided on the radial outer side of the hub, a dynamic ring sealing wedge is provided on the radial inner side of the dynamic ring, and the hub sealing wedge and the dynamic ring sealing wedge form a sealing structure.

[0012] Furthermore, the sealing channel between the hub sealing wedge and the dynamic ring sealing wedge is arranged at an angle with the impeller axis, and the angle ranges from 32° to 60°.

[0013] Furthermore, the angle is 45°.

[0014] Furthermore, the hub sealing wedge and the dynamic ring sealing wedge are both made of alloy material.

[0015] Further, D11=1.5D12, D21=0.6D22.

[0016] Furthermore, the guide blades at the front end of the impeller upper cover plate are straight blades.

[0017] Furthermore, the small blades on the inner side of the impeller upper cover plate are bent and twisted blades, and the installation direction of the small blades on the inner side of the impeller upper cover plate is opposite to that of the impeller blades.

[0018] A sealing structure of a turboexpander according to the present invention, the inlet diameter of the left impeller is D11, the outlet diameter of the left impeller is D21, the inlet diameter of the right impeller is D12, the outlet diameter of the right impeller is D22, D11 > D12, D21 < D22; the turboexpander also includes an outlet pipe, a nozzle cover plate, a nozzle pressure plate, a nozzle, and an impeller guide cover plate. The sealing structures of the left and right turboexpanders both include a volute sealing cover plate and a nozzle sealing cover plate; the outlet pipe has an outlet pipe inlet end groove at the inlet end, and the impeller guide cover plate is inserted into the outlet pipe inlet end groove and forms an impeller end radial sealing structure with the outlet pipe. The radial wall surface of the outlet pipe inlet end groove is evenly distributed with outlet pipe conical sealing rings, and the radial end face on the outlet side of the impeller guide cover plate is evenly distributed with impeller guide cover plate circular sealing rings. The outlet pipe conical sealing rings and the impeller guide cover plate circular sealing rings are arranged in an alternating manner. The outlet pipe is provided with an outlet pipe sealing pressure increasing channel, one end of the outlet pipe sealing pressure increasing channel communicates with the impeller end radial sealing structure, and the other end communicates with a high-pressure gas cylinder; the impeller guide cover plate has an impeller guide cover plate ring groove on the radial inner side of the end, and the impeller upper cover plate is inserted into the impeller guide cover plate ring groove and forms an impeller end axial sealing structure with the impeller guide cover plate. The inner side wall of the outlet end of the impeller upper cover plate is provided with inner small blades of the impeller upper cover plate, and the end wall of the outlet end of the impeller upper cover plate is provided with front guide small blades of the impeller upper cover plate. The inner small blades of the impeller upper cover plate and the front guide small blades of the impeller upper cover plate both have gaps with the impeller guide cover plate ring groove. The impeller guide cover plate is provided with an impeller sealing pressure increasing channel, one end of the impeller sealing pressure increasing channel communicates with the impeller end axial sealing structure, and the other end communicates with a high-pressure gas cylinder; the sealing structure also includes a shaft side sealing structure, and the shaft side sealing structure adopts a dynamic ring and static ring sealing structure. Due to the improvement of the sealing structure of the turboexpander, the leakage amount is reduced, the sealing performance is enhanced, and thus the adaptability and production efficiency are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of a turboexpander in the prior art;

[0020] Figure 2 is a schematic structural diagram of the improved structure of the left or right turboexpander;

[0021] Figure 3 is a schematic diagram of the impeller end radial sealing structure and the impeller end axial sealing structure;

[0022] Figure 4 is a schematic diagram of the shaft side sealing structure.

[0023] In the figure: outlet pipe 1, volute sealing cover plate 2, nozzle sealing cover plate 3, nozzle cover plate 4, nozzle pressure plate 5, nozzle 6, impeller guide cover plate 7, outlet pipe cone sealing ring 81, impeller guide cover plate round sealing ring 82, outlet pipe sealing boosting channel 83, impeller guide cover plate ring groove 91, impeller upper cover plate inner side small blades 92, impeller upper cover plate front end guide small blades 93, impeller sealing boosting channel 94, impeller lower cover plate sealing ring 10, static ring 11, dynamic ring 12, stud bolt 13, static ring inner sealing groove 131, static ring outer sealing groove 132, dynamic and static sealing spring 14, hub sealing wedge 15, dynamic ring sealing wedge 16, left impeller inlet diameter D11, left impeller outlet diameter D21, right impeller inlet diameter D12, right impeller outlet diameter D22. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0026] like Figure 1-4As shown in the figure, a sealing structure of a turboexpander, the turboexpander includes a generator, a left turboexpander, and a right turboexpander; the left turboexpander and the right turboexpander are respectively arranged on the left and right sides of the generator; characterized in that: there are differences in the sizes of the left turboexpander and the right turboexpander; the left turboexpander includes a left bearing, a left sealing structure, a left impeller, a left volute, and a left rotor shaft, the left volute is provided with a left air inlet and a left air outlet, the left impeller is installed on the left rotor shaft, the right turboexpander includes a right bearing, a right sealing structure, a right impeller, a right volute, and a right rotor shaft, the right volute is provided with a right air inlet and a right air outlet, the right impeller is installed on the right rotor shaft; where the left impeller inlet diameter is D11, the left impeller outlet diameter is D21, the right impeller inlet diameter is D12, the right impeller outlet diameter is D22, D11 > D12, D21 < D22; the turboexpander also includes an outlet pipe 1, a nozzle cover plate 4, a nozzle pressure plate 5, a nozzle 6, and an impeller guide cover plate 7, and the sealing structures of the left turboexpander and the right turboexpander both include a volute sealing cover plate 2 and a nozzle sealing cover plate 3; the outlet pipe 1 has an outlet pipe inlet end groove at the inlet end, the impeller guide cover plate 7 is inserted into the outlet pipe inlet end groove and forms an impeller end radial sealing structure with the outlet pipe 1, the radial wall surface of the outlet pipe inlet end groove is evenly distributed with outlet pipe conical sealing rings 81, the radial end surface on the outlet side of the impeller guide cover plate 7 is evenly distributed with impeller guide cover plate circular sealing rings 82, the outlet pipe conical sealing rings 81 and the impeller guide cover plate circular sealing rings 82 are arranged in an alternating manner, the outlet pipe 1 is provided with an outlet pipe sealing pressurizing channel 83, one end of the outlet pipe sealing pressurizing channel 83 communicates with the impeller end radial sealing structure, and the other end communicates with a high-pressure gas cylinder; the impeller guide cover plate 7 has an impeller guide cover plate ring groove 91 on the radial inner side of the end, the impeller upper cover plate is inserted into the impeller guide cover plate ring groove 91 and forms an impeller end axial sealing structure with the impeller guide cover plate 7, the inner side wall of the outlet end of the impeller upper cover plate is provided with inner small blades 92 of the impeller upper cover plate, the end wall of the outlet end of the impeller upper cover plate is provided with front guide small blades 93 of the impeller upper cover plate, both the inner small blades 92 of the impeller upper cover plate and the front guide small blades 93 of the impeller upper cover plate have gaps with the impeller guide cover plate ring groove 91, the impeller guide cover plate 7 is provided with an impeller sealing pressurizing channel 94, one end of the impeller sealing pressurizing channel 94 communicates with the impeller end axial sealing structure, and the other end communicates with a high-pressure gas cylinder; the sealing structure also includes a shaft side sealing structure, and the shaft side sealing structure adopts a dynamic ring and static ring sealing structure.

[0027] Further, the static ring 11 is connected to the volute sealing cover plate 2, and the dynamic ring 12 is connected to the rotor shaft.

[0028] Further, the side of the static ring 11 close to the dynamic ring 12 is provided with a static ring inner sealing groove 131, and the static ring inner sealing groove 131 is provided with a dynamic and static sealing spring 14. One end of the dynamic and static sealing spring 14 is fixed in the static ring inner sealing groove 131, and the other end is movably connected to the dynamic ring 12.

[0029] Furthermore, the impeller lower cover plate is provided with an impeller lower cover plate sealing ring 10, and the side of the static ring 11 close to the impeller is provided with a static ring outer sealing groove 132, and the end of the impeller lower cover plate sealing ring 10 is arranged in the static ring outer sealing groove 132 to form a sealing structure.

[0030] Furthermore, the impeller hub is connected to the rotor shaft via stud bolts 13 , a hub sealing wedge 15 is provided on the radial outer side of the hub, a dynamic ring sealing wedge 16 is provided on the radial inner side of the dynamic ring 12 , and the hub sealing wedge 15 and the dynamic ring sealing wedge 16 form a sealing structure.

[0031] Furthermore, the sealing channel between the hub sealing wedge 15 and the dynamic ring sealing wedge 16 is arranged at an angle with the impeller axis, and the angle ranges from 32° to 60°.

[0032] Furthermore, the angle is 45°.

[0033] Furthermore, the hub sealing wedge 15 and the dynamic ring sealing wedge 16 are both made of alloy material.

[0034] Further, D11=1.5D12, D21=0.6D22.

[0035] Furthermore, the guide blades 93 at the front end of the impeller upper cover plate are straight blades.

[0036] Furthermore, the small blades 92 on the inner side of the impeller upper cover plate are bent and twisted blades, and the installation direction of the small blades 92 on the inner side of the impeller upper cover plate is opposite to that of the impeller blades.

[0037] The sealing structure of the turbine expander of the present invention has a left impeller inlet diameter of D11, a left impeller outlet diameter of D21, a right impeller inlet diameter of D12, a right impeller outlet diameter of D22, D11>D12, D21

Claims

1. A sealing structure of a turbo expander, the turbo expander comprising a generator, a left turbo expander, and a right turbo expander; the left turbo expander and the right turbo expander are respectively arranged on the left and right sides of the generator; characterized in that: The left turbine expander and the right turbine expander are different in size; the left turbine expander includes a left bearing, a left sealing structure, a left impeller, a left volute, and a left rotor shaft. A left air inlet and a left air outlet are provided on the left volute. The left impeller is installed on the left rotor shaft. The right turbine expander includes a right bearing, a right sealing structure, a right impeller, a right volute, and a right rotor shaft. A right air inlet and a right air outlet are provided on the right volute. The right impeller is installed on the right rotor shaft; among them, the inlet diameter of the left impeller is D11, the outlet diameter of the left impeller is D21, the inlet diameter of the right impeller is D12, the outlet diameter of the right impeller is D22, D11 > D12, D21 < D22; the turbine expanders also include an air outlet pipe (1), a nozzle cover plate (4), a nozzle pressing plate (5), a nozzle (6), and an impeller guide cover plate (7). The sealing structures of the left turbine expander and the right turbine expander both include a volute sealing cover plate (2) and a nozzle sealing cover plate (3); the air outlet pipe (1) has an air outlet pipe inlet end groove at the inlet end. The impeller guide cover plate (7) is inserted into the air outlet pipe inlet end groove and forms an impeller end radial sealing structure with the air outlet pipe (1). The radial wall surface of the air outlet pipe inlet end groove is evenly distributed with air outlet pipe conical sealing rings (81). The radial end surface on the outlet side of the impeller guide cover plate (7) is evenly distributed with impeller guide cover plate circular sealing rings (82). The air outlet pipe conical sealing rings (81) and the impeller guide cover plate circular sealing rings (82) are arranged in an alternating manner. An air outlet pipe sealing pressurizing channel (83) is provided on the air outlet pipe (1). One end of the air outlet pipe sealing pressurizing channel (83) communicates with the impeller end radial sealing structure, and the other end communicates with a high-pressure gas cylinder; the impeller guide cover plate (7) has an impeller guide cover plate ring groove (91) on the radial inner side of the end. The impeller upper cover plate is inserted into the impeller guide cover plate ring groove (91) and forms an impeller end axial sealing structure with the impeller guide cover plate (7). The inner side wall of the air outlet end of the impeller upper cover plate is provided with inner small blades (92) of the impeller upper cover plate, and the end wall of the air outlet end of the impeller upper cover plate is provided with front guide small blades (93) of the impeller upper cover plate. The inner small blades (92) of the impeller upper cover plate and the front guide small blades (93) of the impeller upper cover plate both have gaps with the impeller guide cover plate ring groove (91). An impeller sealing pressurizing channel (94) is provided on the impeller guide cover plate (7). One end of the impeller sealing pressurizing channel (94) communicates with the impeller end axial sealing structure, and the other end communicates with a high-pressure gas cylinder; the sealing structure also includes a shaft side sealing structure, and the shaft side sealing structure adopts a dynamic ring and static ring sealing structure.

2. A sealing structure for a turbo expander according to claim 1, characterized in that: The static ring (11) is connected to the volute sealing cover plate (2), and the dynamic ring (12) is connected to the rotor shaft.

3. A sealing structure for a turbo expander according to claim 2, characterized in that: A static ring inner sealing groove (131) is provided on the side of the static ring (11) close to the dynamic ring (12). A dynamic and static sealing spring (14) is provided in the static ring inner sealing groove (131). One end of the dynamic and static sealing spring (14) is fixed in the static ring inner sealing groove (131), and the other end is movably connected to the dynamic ring (12).

4. A sealing structure for a turbo expander according to claim 2, characterized in that: The impeller lower cover plate is provided with an impeller lower cover plate sealing ring (10), a static ring outer sealing groove (132) is provided on the side of the static ring (11) close to the impeller, and the end of the impeller lower cover plate sealing ring (10) is arranged in the static ring outer sealing groove (132) to form a sealing structure.

5. A sealing structure for a turbo expander according to claim 2, characterized in that: The impeller hub is connected to the rotor shaft via stud bolts (13); a hub sealing wedge (15) is arranged on the radial outer side of the hub; a dynamic ring sealing wedge (16) is arranged on the radial inner side of the dynamic ring (12); the hub sealing wedge (15) and the dynamic ring sealing wedge (16) form a sealing structure.

6. A sealing structure for a turbo expander according to claim 5, characterized in that: The sealing channel between the hub sealing wedge (15) and the dynamic ring sealing wedge (16) is arranged at an angle with the impeller axis, and the angle ranges from 32° to 60°.

7. A sealing structure for a turbo expander according to claim 6, characterized in that: The angle is 45°.

8. A sealing structure for a turbo expander according to claim 6, characterized in that: The hub sealing wedge (15) and the dynamic ring sealing wedge (16) are both made of alloy material.

9. A sealing structure for a turbo expander according to claim 1, characterized in that: D11=1.5D12, D21=0.6D22.

10. The sealing structure of a turbo expander according to claim 1, characterized in that: The guide blade (93) at the front end of the impeller upper cover plate is a straight blade.

11. A sealing structure for a turbo expander according to claim 1, characterized in that: The small blades (92) on the inner side of the impeller upper cover plate are bent and twisted blades, and the installation direction of the small blades (92) on the inner side of the impeller upper cover plate is opposite to that of the impeller blades.

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