Method and device for improving the sealing performance of a packing

Abstract

The application provides a method and device for improving packing seal performance, and the method comprises the following steps: S1: determining compensation load and compensation stroke of a to-be-installed disc spring according to parameter information of the packing; S2: obtaining installation space information of the to-be-installed disc spring, and determining a first disc spring according to the installation space information; S3: calculating working load and total deformation of working stroke of the determined first disc spring; S4: judging whether the calculated working load and total deformation of working stroke of the first disc spring match the compensation load and compensation stroke of the to-be-installed disc spring; and S5: if the calculated working load and total deformation of working stroke of the first disc spring match the compensation load and compensation stroke of the to-be-installed disc spring, the first disc spring is installed on the packing. The first disc spring is installed on the packing, so that the packing seal performance can be effectively improved, and long-term reliable operation of equipment is ensured.

Description

Technical Field

[0001] This invention relates to the field of valve packing, and more particularly to a method and apparatus for improving the sealing performance of packing. Background Technology

[0002] In related technologies, valve packing seals come in various forms, with the general sealing principle being the "labyrinth effect." The structure is a combination of a bottom ring, packing, and packing gland. A preload is applied to the packing via packing bolts to achieve a seal. However, this sealing method is not ideal for valves with frequent on / off operations, especially in automatic control system regulating valves. Frequent on / off operations lead to packing wear, resulting in loosening of the packing preload and subsequent leakage. Furthermore, after installation, new packing may experience creep over time, reducing its sealing performance and leading to leakage. Adding a packing disc spring can compensate for the packing sealing load, effectively ensuring sealing performance even under creep and stress relaxation conditions, reducing leakage. However, many valve packing seal structures lack disc springs, and various valve types cannot be fitted with standard disc spring components. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and apparatus for improving the sealing performance of packing, addressing at least one deficiency in the prior art.

[0004] The technical solution adopted by this invention to solve its technical problem is: to construct a method for improving the sealing performance of packing, the method comprising the following steps:

[0005] S1: Based on the packing parameters, determine the compensation load and compensation stroke of the disc spring to be installed;

[0006] S2: Obtain the installation space information of the disc spring to be installed, and determine the first disc spring based on the installation space information;

[0007] S3: Calculate the working load and total deformation of the first disc spring during its working stroke;

[0008] S4: Determine whether the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed;

[0009] S5: If the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed, then the first disc spring is installed on the packing.

[0010] Preferably, S1 includes:

[0011] S11: Calculate the packing torque and packing load, and determine the compensation load of the disc spring to be installed based on the packing torque and packing load.

[0012] Preferably, S1 further includes:

[0013] S12: Determine the disc spring compensation stroke based on the packing compression and relaxation rate.

[0014] Preferably, the compensating stroke of the disc spring to be installed is calculated according to the following formula: S1 = S y *S s *A, where S1 is the stroke of the disc spring to be installed for compensation; S y S is the packing compression amount. s denoted as packing relaxation rate; A represents packing safety margin.

[0015] Preferably, S2 includes:

[0016] S21: Obtain the range of inner and outer diameters and the range of installation height of the disc spring to be installed;

[0017] S22: Select or design the first disc spring according to the range of inner and outer diameters and the range of installation height.

[0018] The present invention also provides an apparatus for improving the sealing performance of packing, the apparatus comprising:

[0019] The first determining module is used to determine the compensation load and compensation stroke of the disc spring to be installed based on the parameter information of the packing.

[0020] The second determining module is used to obtain the installation space information of the disc spring to be installed, and to determine the first disc spring based on the installation space information;

[0021] The calculation module is used to calculate the working load and total deformation of the first disc spring during its working stroke.

[0022] The judgment module is used to determine whether the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed.

[0023] An additional module is used to install the first disc spring onto the packing if the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed.

[0024] Preferably, the first determining module includes:

[0025] The disc spring compensation load determination module is used to calculate the packing torque and the packing load, and determine the disc spring compensation load to be installed based on the packing torque and the packing load.

[0026] Preferably, the first determining module further includes:

[0027] The disc spring compensation stroke determination module is used to determine the compensation stroke of the disc spring to be installed based on the compression and relaxation rate of the packing.

[0028] Preferably, the disc spring compensation stroke determination module includes:

[0029] The first calculation module is used to calculate the compensation stroke of the disc spring to be installed according to the following formula: S1 = S y *S s *A, where S1 is the stroke of the disc spring to be installed for compensation; S y S is the packing compression amount. s denoted as packing relaxation rate; A represents packing safety margin.

[0030] Preferably, the second determining module includes:

[0031] The acquisition module is used to acquire the range of inner and outer diameters and the range of installation height of the disc spring to be installed;

[0032] The selection or design module is used to select or design the first disc spring based on the range of inner and outer diameters and the range of installation height.

[0033] By implementing this invention, the following beneficial effects are achieved:

[0034] This invention can effectively improve the sealing performance of the packing by adding a first disc spring to the packing, thus ensuring the long-term reliable operation of the equipment. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0036] Figure 1 This is a schematic diagram of the structure of the first disc spring mounted on the packing in some embodiments of the present invention;

[0037] Figure 2 This is a flowchart of a method for improving packing sealing performance in some embodiments of the present invention;

[0038] Figure 3 This is a logic block diagram of a device for improving packing sealing performance in some embodiments of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figure 1 The diagram shows the structure of the first disc spring 1 installed on the packing 2. In some embodiments, the specific steps for installing the first disc spring 1 are as follows: (1) Check the sealing surfaces of the packing chamber and the valve stem 10. (2) After the sealing surfaces of the packing chamber and the valve stem 10 are qualified, install the new packing 2 in sequence and press the packing 2 with the packing gland 3. (3) Reinstall the first disc spring 1 and the packing nut 5 on the gland flange 4 of the packing gland 3, wherein the first disc spring 1 is installed by compression through the packing bolt 6. (4) Calculate the packing sealing torque and tighten the packing nut 5 according to the calculated packing sealing torque value. (5) After the valve is operated multiple times, tighten the packing nut 5 to the calculated packing sealing torque value, and the installation is completed.

[0041] Furthermore, the working principle of the first disc spring 1 is as follows: (a) Under normal circumstances, after the packing bolt 6 compresses the first disc spring 1, the disc spring force of the first disc spring 1 is transmitted to the packing part and applies a preload force to the packing 2, so that the packing 2 meets the sealing requirements. (b) When the packing 2 experiences wear and stress relaxation due to long-term operation, the disc spring force of the first disc spring 1 compensates for the preload force of the packing 2, so that the packing 2 can still maintain its sealing performance.

[0042] See also Figure 2 In some embodiments, a method for improving the sealing performance of packing 2 according to the present invention includes the following steps:

[0043] S1: Based on the parameter information of packing 2, determine the compensation load and compensation stroke of the disc spring to be installed;

[0044] S2: Obtain the installation space information of the disc spring to be installed, and determine the first disc spring 1 based on the installation space information;

[0045] S3: Calculate the working load and total deformation of the first disc spring 1 during its working stroke;

[0046] S4: Determine whether the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed;

[0047] S5: If the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed, then the first disc spring 1 is installed on the packing 2.

[0048] In some embodiments, step S1 further includes: step S11: calculating the packing torque and packing load, and determining the compensation load to be added by the disc spring based on the packing torque and packing load. In some embodiments, the valve packing torque calculation parameters are designed by comparing the valve packing torque calculation method in the mechanical design manual, the valve packing improvement technical standard of the Electric Power Research Institute (EPRI), and the Static Machinery Department document "Guidelines for Flexible Graphite Packing Seals and Installation of Valves". Table 1 shows an example of the packing torque calculation parameters.

[0049]

[0050]

[0051] Table 1

[0052] Furthermore, the packing load is calculated according to the following formula: Where F is the packing load, N; k2 is the packing flexibility coefficient; k1 is the valve safety factor; k3 is the packing height correction coefficient; D is the stuffing box inner diameter, mm; d c Valve stem outer diameter, mm; p a denoted as medium pressure (bar); S as packing width (mm); μ as the average coefficient of friction between packing 2, valve stem 10, and stuffing box; and H as packing height (mm).

[0053] Calculate the packing torque using the following formula. Where T is the packing torque, Nm; Pinch is the bolt pitch, mm; f1 is the friction coefficient between threads; f2 is the friction coefficient between the nut and the washer; r is the thread tip radius of the bolt, mm; R ma The arithmetic mean of the nominal radius of the screw and the radius of the nut seat surface is given in mm. Specifically, by using different safety factors k1, the load on the packing seal is calculated to be between 10000N and 12000N. Therefore, the working force range for the disc spring to be installed is initially selected to be between 10000N and 12000N. Since the packing 2 is loaded with torque, the corresponding load can be converted into torque.

[0054] In some embodiments, step S1 further includes: S12: determining the compensating stroke to be added with the disc spring based on the compression and relaxation rate of the packing 2. Specifically, the compensating stroke to be added with the disc spring is calculated according to the following formula: S1 = S y *S s *A, where S1 is the travel of the disc spring compensation to be installed, in mm; S y Packing compression amount, mm; S s denoted as packing relaxation rate; A represents packing safety margin.

[0055] In some embodiments, step S2 further includes:

[0056] S21: Obtain the range of inner and outer diameters and the range of installation heights of the disc spring to be installed;

[0057] S22: Select or design the first disc spring 1 according to the range of inner and outer diameter dimensions and the range of installation height.

[0058] In some embodiments, the stiffness of the first disc spring 1 and the combined installation method of the first disc spring 1 can be matched according to the range of inner and outer diameters, the range of installation heights, and the compensation load and compensation stroke of the disc spring to be installed, and the first disc spring 1 can be designed with reference to the national standard "Disc Springs". Table 2 shows an example of the designed first disc spring 1:

[0059]

[0060]

[0061] Table 2

[0062] The load on the first disc spring 1 of the composite assembly is calculated according to the following formula: In the formula, F R To account for friction, the load on the first disc spring 1 is N; F is the load on a single first disc spring 1, N; n is the number of disc springs 1 in the stacked assembly; f M The coefficient of friction between the conical surfaces of the first disc spring is 1.

[0063] The stiffness of the first disc spring 1 is calculated using the following formula. Where F′ is the stiffness of the first disc spring 1, N / mm; E is the elastic modulus, N / mm; K1 and K4 are calculation coefficients; t is the thickness of the first disc spring 1, mm; D is the outer diameter of the first disc spring 1, mm; h0 is the calculated value of the deformation of the first disc spring 1 when compressed, mm; and f is the deformation of a single first disc spring 1, mm.

[0064] S4: Determine whether the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed; S5: If the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed, then install the first disc spring 1 on the packing 2. The installation of the matching first disc spring 1 can compensate for the relaxation creep and wear of the packing 2, thereby improving the sealing performance of the packing 2. Specifically, assuming the packing 2 relaxes during operation, the disc spring force of the first disc spring 1 compensates for the preload of the packing 2, allowing the packing 2 to maintain its sealing performance.

[0065] like Figure 3 The diagram shown is a logic block diagram of an apparatus for improving the sealing performance of packing 2 according to some embodiments of the present invention. The apparatus for improving the sealing performance of packing 2 in this embodiment includes:

[0066] The first determining module is used to determine the compensation load and compensation stroke of the disc spring to be installed based on the parameter information of packing 2.

[0067] The second determining module is used to obtain the installation space information of the disc spring to be installed, and to determine the first disc spring 1 based on the installation space information;

[0068] The calculation module is used to calculate the working load and total deformation of the first disc spring 1 during its working stroke.

[0069] The judgment module is used to determine whether the calculated working load and total deformation of the first disc spring 1 are matched with the compensation load and compensation stroke of the disc spring to be installed.

[0070] An additional module is used to install the first disc spring 1 onto the packing 2 if the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed.

[0071] In some embodiments, the first determining module includes a disc spring compensation load determining module, which is used to calculate the packing torque and the packing load, and determine the disc spring compensation load to be installed based on the packing torque and the packing load.

[0072] Furthermore, the packing load is calculated according to the following formula: Where F is the packing load, N; k2 is the packing flexibility coefficient; k1 is the valve safety factor; k3 is the packing height correction coefficient; D is the stuffing box inner diameter, mm; d c Valve stem outer diameter, mm; p a denoted as medium pressure (bar); S as packing width (mm); μ as the average coefficient of friction between packing 2, valve stem 10, and stuffing box; and H as packing height (mm).

[0073] Calculate the packing torque using the following formula. Where T is the packing torque, Nm; Pinch is the bolt pitch, mm; f1 is the friction coefficient between threads; f2 is the friction coefficient between the nut and the washer; r is the thread tip radius of the bolt, mm; R ma The arithmetic mean of the nominal radius of the screw and the radius of the nut seat surface is expressed in mm. In some embodiments, assuming that the packing seal load is calculated to be between 10000N and 12000N using different safety factors k1, the working force range of the disc spring to be installed is initially selected to be between 10000N and 12000N. Since the packing 2 is loaded with torque, the corresponding load can be converted into torque.

[0074] In some embodiments, the first determining module further includes a disc spring compensation stroke determining module, which is used to determine the disc spring compensation stroke to be installed based on the compression and relaxation rate of the packing 2. Specifically, the disc spring compensation stroke determining module includes a first calculation module, which is used to calculate the disc spring compensation stroke to be installed according to the following formula: S1 = S y *S s *A, where S1 is the travel of the disc spring compensation to be installed, in mm; S y Packing compression amount, mm; S s denoted as packing relaxation rate; A represents packing safety margin.

[0075] In some embodiments, the second determining module includes:

[0076] The acquisition module is used to acquire the range of inner and outer diameters and the range of installation height of the disc spring to be installed;

[0077] The selection or design module is used to select or design the first disc spring 1 based on the range of inner and outer diameter dimensions and the range of installation height.

[0078] In some embodiments, the stiffness of the first disc spring 1 and the combined installation method of the first disc spring 1 can be matched according to the range of inner and outer diameter dimensions, the range of installation height, and the compensation load and compensation stroke of the disc spring to be installed.

[0079] The load on the first disc spring 1 of the composite assembly is calculated using the following formula: In the formula, F R To account for friction, the load on the first disc spring 1 is N; F is the load on a single first disc spring 1, N; n is the number of disc springs 1 in the stacked assembly; f M The coefficient of friction between the conical surfaces of the first disc spring is 1.

[0080] The stiffness of the first disc spring 1 is calculated using the following formula. Where F′ is the stiffness of the first disc spring 1, N / mm; E is the elastic modulus, N / mm; K1 and K4 are calculation coefficients; t is the thickness of the first disc spring 1, mm; D is the outer diameter of the first disc spring 1, mm; h0 is the calculated value of the deformation of the first disc spring 1 when compressed, mm; and f is the deformation of a single first disc spring 1, mm.

[0081] The judgment module determines whether the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed. The installation module installs the first disc spring 1 onto the packing 2 if the calculated working load and total deformation of the first disc spring 1 match the compensation load and compensation stroke of the disc spring to be installed. The installation of the matching first disc spring 1 can compensate for the relaxation creep and wear of the packing 2, thereby improving the sealing performance of the packing 2. Specifically, assuming the packing 2 relaxes during operation, the spring force of the first disc spring 1 compensates for the preload of the packing 2, allowing the packing 2 to maintain its sealing performance.

[0082] By implementing this invention, the following beneficial effects are achieved:

[0083] The present invention can effectively improve the sealing performance of the packing 2 by adding a first disc spring 1 to the packing 2, thus ensuring the long-term reliable operation of the equipment.

[0084] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for improving the sealing performance of packing, characterized in that, The method includes the following steps: S1: Based on the packing parameters, determine the compensation load and compensation stroke of the disc spring to be installed; S2: Obtain the installation space information of the disc spring to be installed, and determine the first disc spring based on the installation space information; S3: Calculate the working load and total deformation of the first disc spring based on the determined working stroke; S4: Determine whether the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed; S5: If the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed, then the first disc spring is installed on the packing. Wherein, S1 includes: S11: Calculate the packing torque and packing load, and determine the compensation load of the disc spring to be installed based on the packing torque and packing load. S12: Determine the compensation stroke of the disc spring to be installed based on the compression and relaxation rate of the packing.

2. The method for improving the sealing performance of packing according to claim 1, characterized in that, The compensation stroke of the disc spring to be installed is calculated using the following formula. ,in, To be installed with disc springs to compensate for the travel; This refers to the packing compression amount; denoted as packing relaxation rate; A represents packing safety margin.

3. The method for improving the sealing performance of packing according to claim 1, characterized in that, S2 includes: S21: Obtain the range of inner and outer diameters and the range of installation height of the disc spring to be installed; S22: Select or design the first disc spring according to the range of inner and outer diameters and the range of installation height.

4. A device for improving the sealing performance of packing, characterized in that, The device includes: The first determining module is used to determine the compensation load and compensation stroke of the disc spring to be installed based on the packing parameter information; S11: calculate the packing torque and packing load, and determine the compensation load of the disc spring to be installed based on the packing torque and packing load; S12: determine the compensation stroke of the disc spring to be installed based on the packing compression and relaxation rate. The second determining module is used to obtain the installation space information of the disc spring to be installed, and to determine the first disc spring based on the installation space information; The calculation module is used to calculate the working load and total deformation of the first disc spring during its working stroke. The judgment module is used to determine whether the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed. An additional module is used to install the first disc spring onto the packing if the calculated working load and total deformation of the first disc spring match the compensation load and compensation stroke of the disc spring to be installed.

5. The device for improving the sealing performance of packing according to claim 4, characterized in that, The first determining module includes: The disc spring compensation load determination module is used to calculate the packing torque and the packing load, and determine the disc spring compensation load to be installed based on the packing torque and the packing load.

6. The device for improving the sealing performance of packing according to claim 4, characterized in that, The first determining module further includes: The disc spring compensation stroke determination module is used to determine the compensation stroke of the disc spring to be installed based on the compression and relaxation rate of the packing.

7. The device for improving the sealing performance of packing according to claim 6, characterized in that, The disc spring compensation stroke determination module includes: The first calculation module is used to calculate the compensation stroke of the disc spring to be installed according to the following formula. in, To be installed with disc springs to compensate for the travel; This refers to the packing compression amount; denoted as packing relaxation rate; A represents packing safety margin.

8. The device for improving the sealing performance of packing according to claim 6, characterized in that, The second determining module includes: The acquisition module is used to acquire the range of inner and outer diameters and the range of installation height of the disc spring to be installed; The selection or design module is used to select or design the first disc spring based on the range of inner and outer diameters and the range of installation height.

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