Sealing structure for nozzle adjusting device of turbo expander

Abstract

The utility model relates to the field of hydrogen expanders, in particular to a sealing structure for a nozzle adjusting device of a turbo expander. Comprising a shell, a driving shaft is arranged in the middle of the shell in a penetrating mode, and the inner wall of the shell and the outer edge face of the driving shaft form a first cavity for containing a magnetofluid assembly; the magnetic fluid assembly comprises a pole shoe and a permanent magnet which are arranged around the driving shaft, and a magnetic fluid filled in a gap between the pole shoe and the driving shaft; the magnetic fluid gathers around the driving shaft under the action of magnetic force of the permanent magnet and forms a magnetic sealing ring; the shell is provided with a hollow interlayer adjacent to the first cavity, and a heating device is installed in the interlayer. Sealing between the nozzle adjusting device and the expansion machine body is achieved through the magnetofluid assembly, and compared with a traditional rubber sealing ring, magnetofluid sealing is not prone to aging, abrasion is avoided, and high durability is achieved.

Description

Technical Field

[0001] The utility model relates to the field of hydrogen expanders, in particular to a sealing structure for a nozzle regulating device of a turbine expander. Background Art

[0002] A turboexpander is a mechanical device that uses a certain pressure gas to expand adiabatically in a turbine to do work externally and consume the internal energy of the gas itself, thereby strongly cooling the gas itself to achieve the purpose of refrigeration. The expansion of the gas is mainly carried out in the nozzle. By adjusting the nozzle, the flow rate of the expander can be controlled to adapt to different working conditions.

[0003] Magnetic fluid sealing technology is a process that utilizes the principles of magnetic field and fluid mechanics. Under the action of the magnetic field generated by the magnet, the magnetic fluid placed in the gap between the shaft and the top of the pole shoe is concentrated to form a so-called "O" ring, which blocks the gap channel and achieves sealing.

[0004] However, the working gas temperature of the hydrogen turbine expander is about -200℃, which is much lower than the working temperature of the magnetic fluid of -30℃-120℃. In addition, the cold energy will be transmitted along the drive shaft to the magnetic fluid component at the seal, thus causing the magnetic fluid to solidify at low temperature and fail to work. Therefore, in the prior art, there has been no application of magnetic fluid sealing technology in hydrogen turbine expanders. Utility Model Content

[0005] The utility model aims to provide a sealing structure for a nozzle regulating device of a turbine expander, so as to solve the technical problem that magnetic fluid seals in the prior art cannot be applied to hydrogen turbine expanders.

[0006] The technical solution of the utility model is: a sealing structure for a nozzle adjustment device of a turbine expander, comprising:

[0007] A housing, wherein a driving shaft is provided through the middle thereof, wherein the inner wall of the housing and the outer edge surface of the driving shaft form a first chamber for accommodating the magnetic fluid component;

[0008] The magnetic fluid assembly includes a pole shoe and a permanent magnet arranged around the drive shaft, and a magnetic fluid filled in the gap between the pole shoe and the drive shaft; the magnetic fluid gathers around the drive shaft under the magnetic force of the permanent magnet and forms a magnetic sealing ring;

[0009] The shell has a hollow interlayer arranged adjacent to the first chamber, and a heating device is installed in the interlayer.

[0010] Preferably, a ring groove is formed on a side of the pole shoe close to the driving shaft, and the magnetic sealing ring is formed in the ring groove.

[0011] Preferably, the magnetic fluid components are arranged in plurality along the axial direction in the first chamber; and the interlayer extends from one end to the other end of the first chamber.

[0012] Preferably, the drive shaft has a shoulder with an increased diameter, one end face of the shoulder serves as a boundary of the end of the first chamber, and the outer edge is matched with the shell, and a tooth groove is provided at the matching position.

[0013] Preferably, the drive shaft is formed by connecting a first drive shaft and a second drive shaft, the first drive shaft and the second drive shaft both have a T-shaped head, and the shoulder is formed by coaxially connecting the heads of the first drive shaft and the second drive shaft.

[0014] Preferably, the head of the second drive shaft is grooved along the axial direction so that the shaft shoulder formed after the connection is hollow inside to form a second chamber, and the second chamber is used to reduce the cross-sectional area of ​​the corresponding position of the drive shaft perpendicular to the axial direction.

[0015] Preferably, the shell is grooved at one end away from the interlayer to form a third chamber, and the third chamber is used to reduce the cross-sectional area of ​​the shell at a corresponding position perpendicular to the axial direction.

[0016] Compared with the prior art, the advantages of the utility model are:

[0017] (1) The utility model realizes the sealing between the nozzle adjustment device and the expander body through the magnetic fluid component. Compared with the traditional rubber sealing ring, the magnetic fluid seal is not easy to age and will not wear, and has strong durability.

[0018] (2) The utility model has an interlayer at a position adjacent to the magnetic fluid component of the shell, in which a heating belt is installed, and a temperature sensor is used to maintain the magnetic fluid component at a normal operating temperature, thereby avoiding the problem of overcooling and solidification due to the drive shaft having an excessively low temperature.

[0019] (3) In one embodiment of the utility model, the drive shaft is configured as a structure in which the first drive shaft and the second drive shaft are coaxially connected by welding. By axially slotting the end face of the second drive shaft, a hollow second chamber is formed inside the shoulder of the drive shaft after welding, so that the cross-sectional area perpendicular to the axis at this point is reduced, resulting in a decrease in heat transfer efficiency when the cold at one end of the shoulder close to the expander body is transferred to the second chamber, thereby avoiding overcooling and solidification of the magnetic fluid.

[0020] (4) The utility model provides a third chamber at one end of the shell close to the expander body, thereby reducing the cross-sectional area of ​​the shell at this position, making it difficult for the cold energy of the expander body to be transferred to the magnetic fluid component, which helps to maintain the magnetic fluid component at a normal operating temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0022] Figure 1 This is a structural diagram of the nozzle adjustment device, sealing structure and driver of the utility model;

[0023] Figure 2 It is a cross-sectional view of the sealing structure of the utility model;

[0024] Figure 3 It is a cross-sectional view of the sealing structure of the utility model;

[0025] Figure 4 This is an enlarged view of point A described in the utility model;

[0026] Figure 5 This is an enlarged view of point B described in the utility model;

[0027] Figure 6 This is a structural diagram of a drive shaft in another embodiment of the utility model;

[0028] Among them: 11. nozzle adjustment device, 12. drive shaft, 121. first drive shaft, 122. second drive shaft, 13. driver, 14. lever, 2. shell, 31. end cover, 32. turbine expander body, 4. first chamber, 5. magnetic fluid assembly, 51. pole shoe, 52. permanent magnet, 53. annular groove, 6. interlayer, 7. heating belt, 8. tooth groove, 9. third chamber, 10. second chamber. DETAILED DESCRIPTION

[0029] The following is a further detailed description of the present invention in conjunction with specific embodiments:

[0030] A sealing structure for a turbine expander nozzle adjustment device 11, such as Figure 1 As shown, the nozzle adjusting device 11 is sleeved on the driving shaft 12, and the driving shaft 12 rotates under the drive of the driver 13, and drives the lever 14 to control the opening of the nozzle adjusting device 11. Figure 2 and Figure 3 As shown, the sealing structure includes a housing 2, a drive shaft 12 is arranged through the middle of the housing 2, and an end cover 31 is arranged at one end of the housing 2, and the other end is connected to the turbine expander body 32. A cavity is formed between the interior of the housing 2 and the outer edge surface of the drive shaft 12, and the cavity is configured as a first chamber 4, and a magnetic fluid component 5 is arranged in the first chamber 4 to achieve sealing of the drive shaft 12.

[0031] The magnetic fluid assembly 5 includes a pole shoe 51, which is sleeved on the outer wall of the drive shaft 12, and the outer edge surface of the pole shoe 51 and the housing 2 are sealed by an O-ring, and the area A between the inner edge surface and the drive shaft 12 is filled with magnetic fluid (not shown in the figure). A permanent magnet 52 is installed at one end of the pole shoe 51, and the magnetic field generated by the permanent magnet 52 causes the magnetic fluid at area A to gather around the drive shaft 12 and form a magnetic sealing ring, thereby achieving sealing between the inner edge surface of the pole shoe 51 and the outer wall of the drive shaft 12.

[0032] In a preferred embodiment of the utility model, an annular groove 53 is provided on the inner edge surface of the pole shoe 51, and the annular groove 53 is used to constrain the magnetic fluid, and the magnetic fluid is filled in the space formed by the annular groove 53 and the outer wall of the drive shaft 12. The magnetic fluid assembly 5 can be arranged in multiple groups along the axial direction according to the requirements of the sealing pressure, and jointly undertake the sealing function, thereby further enhancing the sealing performance of the magnetic fluid assembly 5.

[0033] The working gas temperature of the turbine expander is -200°C, while the working temperature of the magnetic fluid is between -30°C and 120°C. Direct application of the magnetic fluid component 5 to the turbine expander will cause the magnetic fluid to solidify at low temperature and lose fluidity. To solve this problem, the utility model provides a hollow interlayer 6 at one end of the shell 2, the interlayer 6 is arranged adjacent to the first chamber 4, extending from one end of the first chamber 4 to the other end of the first chamber 4, and a heating belt 7 is installed inside the interlayer 6 for heating the first chamber 4.

[0034] like Figure 2 and Figure 4 As shown, the drive shaft 12 is provided with a shoulder with an increased diameter, one end of which serves as the boundary of the first chamber 4 and abuts against the pole shoe 51. The outer edge of the shoulder fits with the housing 2, in order to reduce the amount of hydrogen leaked and reduce the pressure leaked to the magnetic fluid assembly 5, as shown in FIG. Figure 2 Middle B and Figure 5 As shown, the outer edge of the shaft shoulder is provided with tooth grooves 8. The tooth grooves 8 have an uneven structure, so that when the fluid at one end of the shaft shoulder passes through these tooth grooves 8, multiple throttling occurs, resulting in a pressure drop of the fluid, reducing the sealing burden of the magnetic fluid assembly 5.

[0035] In this embodiment, the magnetic fluid is directly attached to the drive shaft 12, causing the cold of the drive shaft 12 to be transferred to the magnetic fluid faster than the heat of the heating belt 7, causing the magnetic fluid to overcool and solidify, thereby losing its sealing effect.

[0036] Therefore, in another embodiment of the present application, Figure 6As shown, the drive shaft 12 is formed by coaxially connecting the first drive shaft 121 and the second drive shaft 122 at the shoulder position. The first drive shaft 121 and the second drive shaft 122 are both set to a T-shaped structure and have a head with a larger diameter. Among them, the head of the second drive shaft 122 is deep grooved along the axis, so that the cross-sectional area of ​​the second drive shaft 122 perpendicular to the axis at the groove becomes smaller. The first drive shaft 121 and the head of the second drive shaft 122 are coaxially fixed by welding or the like, so that the groove of the second drive shaft 122 is closed and serves as the second hollow chamber 10 inside the drive shaft 12 after welding. Because the physical cross-sectional area of ​​the drive shaft 12 at the second chamber 10 is small, when the cold amount of the drive shaft 12 close to the end of the turbine expander body 32 is transferred to the second chamber 10, its heat transfer efficiency is greatly reduced, which helps to maintain the magnetic fluid at a preset working temperature. In addition, in other embodiments of the present application, the connection method of the first drive shaft 121 and the second drive shaft 122 is not limited to welding, and can also be connected by a coupling.

[0037] like Figure 3 As shown, the housing 2 is connected to the end of the turbo expander so that the heat of the magnetic fluid will be absorbed by the turbo expander. Therefore, a third chamber 9 is provided at one end of the housing 2 close to the turbo expander body 32, so that the cross-sectional area of ​​the housing 2 perpendicular to the axis at this position is reduced, thereby reducing the heat loss rate of the magnetic fluid. The connection section between the housing 2 and the turbo expander is sealed with an O-ring.

[0038] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model.

Claims

1. A sealing structure for a nozzle adjustment device of a turbo expander, characterized in that: include: A housing, wherein a driving shaft is provided through the middle thereof, wherein the inner wall of the housing and the outer edge surface of the driving shaft form a first chamber for accommodating the magnetic fluid component; The magnetic fluid assembly includes a pole shoe and a permanent magnet arranged around the drive shaft, and a magnetic fluid filled in the gap between the pole shoe and the drive shaft; The magnetic fluid gathers around the driving shaft under the magnetic force of the permanent magnet and forms a magnetic sealing ring; The shell has a hollow interlayer arranged adjacent to the first chamber, and a heating device is installed in the interlayer.

2. A sealing structure for a nozzle adjustment device of a turbo expander according to claim 1, characterized in that: A ring groove is formed on one side of the pole shoe close to the driving shaft, and the magnetic sealing ring is formed in the ring groove.

3. A sealing structure for a nozzle adjustment device of a turbo expander according to claim 2, characterized in that: The magnetic fluid components are arranged in plurality along the axial direction in the first chamber; the interlayer extends from one end to the other end of the first chamber.

4. A sealing structure for a nozzle adjustment device of a turbo expander according to claim 1, characterized in that: The driving shaft has a shoulder with an increased diameter, one end face of the shoulder serves as the boundary of the end of the first chamber, and the outer edge thereof is matched with the shell, and a tooth groove is provided at the matching position.

5. A sealing structure for a nozzle adjustment device of a turbo expander according to claim 4, characterized in that: The drive shaft is formed by connecting a first drive shaft and a second drive shaft, the first drive shaft and the second drive shaft both have a T-shaped head, and the shaft shoulder is formed by coaxially connecting the heads of the first drive shaft and the second drive shaft.

6. A sealing structure for a nozzle adjustment device of a turbo expander according to claim 5, characterized in that: The head of the second drive shaft is grooved along the axial direction, so that the shaft shoulder formed after the connection is hollow inside to form a second chamber, and the second chamber is used to reduce the cross-sectional area of ​​the corresponding position of the drive shaft perpendicular to the axial direction.

7. The sealing structure for a nozzle adjustment device of a turbo expander according to claim 1, characterized in that: The shell is grooved at one end away from the interlayer to form a third chamber, and the third chamber is used to reduce the cross-sectional area of ​​the corresponding position of the shell perpendicular to the axial direction.

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