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National Ship Standardization Technical Committee Professional Standard CB*3345-88
Mechanical seals for marine pump shafts
Published on November 19, 1988
Published by the National Ship Standardization Technical Committee and implemented on May 1, 1989
National Ship Standardization Technical Committee Professional Standard Mechanical seals for marine pump shafts
Subject content and scope of application
CB*334588
Classification number: U47
This standard specifies the product classification, technical requirements, tests and methods, inspection rules, marking and packaging of mechanical seals for internal single-end unbalanced and internal single-end balanced types for ship pump shafts. This standard applies to mechanical seals for rotating shafts of ship power pumps and rotary positive displacement pumps, and also to mechanical seals for rotating shafts of ship auxiliary machines (such as compressors, refrigerators, fans, etc.). The sealing medium can be fresh water, seawater, bilge water, fuel oil and lubricating oil, etc. Its working parameters are: working pressure is 0~1.6MPa (referring to the medium pressure in the sealing cavity), working temperature is -20~100℃ (water medium working temperature is -20~+80C), speed is not more than 3600r/min, and the outer diameter of the mounting shaft (or sleeve) is 10~140mm. 2 Reference standards
GB1184 Shape and position tolerances Provisions for unmarked tolerances Ordinary cylindrical helical springswww.bzxz.net
GB12393
GB3452.1 Dimension series and tolerances of 0-type rubber sealing rings for hydraulic and pneumatic use 3 Product classification
3.1 Type
The type of mechanical seal is shown in Figures 1 and 2. The figure shows an example of using an 0-type ring as an auxiliary sealing ring for a static ring. Other cross-sectional shapes of sealing rings can also be used as auxiliary sealing rings for static rings. 3.1.1F type single end face unbalanced mechanical seal, see Figure 1. 3.1.2P type single end face balanced mechanical seal, see Figure 2. Stationary ring
Swivel ring assembly
3.2 Structural dimensions
3.2:1 Stationary ring limit structure.
National Ship Standardization Technical Committee 1988-11-19 Approved Swivel assembly
1989-05-01 Implementation
CB*3345—88
3.2.1.1 Stationary ring circumferential limit structure: The structure to prevent the stationary ring from rotating circumferentially can adopt a radial position pin structure according to the specific requirements of the equipment used, see Figure 3; or an axial position pin structure, see Figure 4. Static ring
Stationary ring
3.2.1.2 Static ring axial limit structure: The axial limit structure of the static ring of the unbalanced mechanical seal is shown in Figure 5; the axial limit structure of the static ring of the balanced mechanical seal is shown in Figure 6. Other types of static ring axial limit structures can also be used according to the special requirements of the equipment. Limit ring
Limit ring
3.2.2 Dynamic ring transmission structure.
The key on the rotating shaft is used to transmit torque to the dynamic ring seat of the mechanical seal. It is allowed to use an adjustment gasket to achieve the installation size of the mechanical seal. 3.2.3 Mechanical seal end cover.
3.2.3.1 Floating seal end cover without limit ring, see Figure 7. 3.2.3.2 Floating seal end cover with limit ring, see Figure 8. CB*3345—88
3.2.3.3 If the mechanical seal needs internal circulation or flushing, the internal circulation connection hole or flushing hole should be opened on the mechanical seal end cover, and its joint size should comply with Figure 7.
3.3 Basic parameters
3.3.1 The basic dimensional parameters of the mechanical seal structure are shown in Figures 1 to 8 and Table 1. Nominal diameter
Maximum size ds
CB*3345-88
Minimum size
In order to ensure a safe gap between the moving ring and the housing, 43 is recommended as the maximum size and 4 as the minimum size 2
(Number
CB*3345-88
Maximum size L
3.4 Mechanical seal code for marine pump shaft
CB*3345-88
口口口
R Right-handed
Mechanical seal rotation direction L, left-handed
ls Any rotation direction
Mechanical seal nominal diameter
IF Unbalanced mechanical seal
Balanced mechanical seal
Marine pump shaft Mechanical seal
Right-hand rotation: When viewed from the static ring to the moving ring, the moving ring rotates clockwise. Left-hand rotation: When viewed from the static ring to the moving ring, the moving ring rotates counterclockwise. 3.5 Marking example
The marking for a balanced mechanical seal for a marine pump shaft with a nominal diameter of 35mm and left-hand rotation is: P-35LCB*3345—88
4 Technical requirements
-4.1 Mechanical seals for marine pump shafts shall comply with the provisions of this standard and be manufactured in accordance with product drawings and technical documents approved through prescribed procedures. 4.2 Technical requirements for the main parts of mechanical seals 4.2.1 The end faces of mechanical seals, such as when using graphite rings or filled polytetrafluoroethylene rings, as well as assembled moving rings or static rings, shall be subjected to a water pressure test. Unbalanced sealing rings are tested at 1.0MPa, flat The balanced sealing ring is tested for leaks at a water pressure of 2.0MPa, and there should be no leakage for 10 minutes.
4.2.2 The flatness of the sealing end face shall not be less than 0.0009mm, the roughness R of the sealing end face of metal materials shall not be greater than 0.2μm, and the roughness R of the sealing end face of non-metallic materials shall not be greater than 0.4um. 4.2.3 The surface roughness R of the contact part between the dynamic ring and the static ring and the auxiliary sealing ring shall not be greater than 3.2um, and the dimensional tolerance of the outer circle or inner hole shall be h8 or H8.
4.2.4 The perpendicularity of the static ring sealing end face to the outer circle in contact with the static ring auxiliary sealing ring, the perpendicularity of the dynamic ring sealing end face to the inner hole in contact with the dynamic ring auxiliary sealing ring, and the parallelism of the end faces of the dynamic and static ring sealing ends in contact with the auxiliary sealing ring shall all be in accordance with G 7th grade tolerance of B1184.
4.2.5 Tolerances of spring inner diameter, outer diameter, free height, verticality of center line and two end faces, etc., are in accordance with the first-level precision standard requirements of GB-1239. For mechanical seals with multiple springs, the difference in free height of each spring in the same set of mechanical seals shall not exceed 0.5mm. 4.2.6 The inner hole size tolerance of spring seat and transmission seat is F9, and the surface roughness R is not more than 3.2um. 4.2.7 Technical requirements for rubber O-rings refer to GB3452.1. 4.2.8 The end face material of mechanical seal shall have sufficient chemical stability to the sealed medium. When the sealed medium is seawater or bilge water, the main material matching of mechanical seal shall not produce serious electrochemical corrosion, and the end face material of mechanical seal shall have sufficient hardness. 4.3 Performance requirements of mechanical seals
4.3.1 The mechanical seal of marine pump shaft shall be able to meet the marine requirements of pump tilt, swing, impact and vibration. 4.3.2 The average leakage of mechanical seals shall meet the following requirements: When the nominal diameter is less than or equal to 50mm, the average leakage shall not exceed 3mL/h. CB*3345-88
When the nominal diameter is greater than 50mm and less than 100mm, the average leakage shall not exceed 5mL/h. When the nominal diameter is greater than 100mm, the average leakage shall not exceed 8mL/h. 4.3.3 The wear of the end face of the mechanical seal shall meet the requirements for the service life of the mechanical seal. If the test is carried out with clean water, the wear of the end face of the sealing ring made of soft material shall not exceed 0.02mm after 100h of operation. 4.3.4 Under the conditions of correct installation and use, the service life of the mechanical seal shall not be less than one year. 4.4 Installation and use requirements of mechanical seals
4.4.1 The shaft (or sleeve) where the mechanical seal is installed shall meet the dimensional tolerance, geometric tolerance and surface roughness R specified in Table 2.
>50~100
>100~140
Axial runout tolerance
Surface roughness
The end angle of the shaft (or sleeve) where the auxiliary seal ring of the dynamic ring is installed shall meet the requirements of Figure 9. 4.4.2
Lifter connection
4.4.3The axial momentum of the rotating shaft where the mechanical seal is installed shall not exceed 0.2mm during operation
4.4.4The runout tolerance of the positioning end face where the sealing cavity and the sealing end cover fit against the surface of the shaft (or sleeve) shall be in accordance with Table 2.4.4.5The size and surface roughness of the auxiliary seal ring installation part on the sealing end cover shall be in accordance with the provisions of Figure 10 and Table 3. Figure 10
Shaft (or sleeve) outer diameter
>16~50
>50~80
>80~140
CB*3345—88
4.4.6 Before installing the mechanical seal, the shaft (or sleeve), seal cavity, seal end cover and all parts of the mechanical seal must be cleaned to prevent debris from entering the sealing area. 4.4.7 When installing the mechanical seal, the installation dimensions of the mechanical seal shall be ensured in accordance with the requirements in the product installation and operating instructions or samples. 4.4.8 When the temperature of the conveying medium is too high or too low, contains foreign particles, or is toxic, appropriate blocking, flushing, cooling and filtering measures must be taken.
5 Test method
5.1 Static pressure test
5.1.1 The pressure of the static pressure test is 1.25 times the product use pressure, and the medium temperature is the ambient temperature. Special requirements shall be agreed upon separately. 5.1.2 Correctly adjust the mechanical seal, make installation records, and exhaust the gas to fill the test system with the test medium. 5.1.3 From the time when the test system pressure reaches the specified value, calculate the test time and measure the leakage. The pressure holding time of the static pressure test shall not be less than 10 minutes.
5.2 Operation test in type test
5.2.1 Use the mechanical seal that has passed the static pressure test to perform the operation test and make installation inspection records. The test pressure is the operating pressure of the product and the test speed is the maximum speed of the product.
5.2.2 Before the test, the gas in the system should be discharged and the test device should be started. When the pressure, temperature and speed are stable at the specified values, the test time should be calculated and the leakage should be measured.
5.2.3 The cumulative test time should not be less than 200 hours. During the cumulative time, the continuous operation time should not exceed 50 hours at a time, and the number of starts and stops should not be less than 10 times.
5.2.4 Measure and record the leakage, speed, temperature and power every 2 hours. The leakage measured each time shall not exceed the specified value. 5.2.5 After completing the type operation test, stop the machine to measure the end face wear of the mechanical seal. 5.3 Operation test in factory test
5.3.1 The operation time of factory test is 5h. The leakage, speed, temperature and power shall be measured and recorded every 1h. The leakage measured each time shall not exceed the specified value.
5.4 Test reports shall be filled in for both static pressure test and operation test. The content and type of test report are shown in Appendix A (reference). 5.5 Mechanical seal test device
5.5.1 The test device of mechanical seal shall meet the requirements of test conditions. Static pressure test and operation test may share a set of devices or use a set of devices for each.
5.5.2 During static pressure test and operation test, the test device shall be equipped with pressure stabilizing equipment. The pressure gauge or other pressure sensing element shall be directly connected to the sealing chamber.
5.5.3 The sensing element for measuring the temperature of the sealed medium shall be properly installed at the appropriate position of the sealing chamber. 5.5.4 The test device shall have a structure that is convenient for collecting the leakage of the medium to reduce the loss and large-scale volatilization of the leaking medium. 5.6 Test instruments
5.6.1 The measuring instruments shall be calibrated by a third-level or above metrology department and shall be issued with a valid certificate. 5.6.2 The test instruments shall comply with the provisions of Table 4. 8
Inspection rules
CB*3345—88
Pointer pressure gauge or other pressure measuring instrument Suitable temperature measuring instrument
Mechanical tachometer, photoelectric tachometer or other tachometer Torque tachometer or other torque measuring device Measuring instrument
Micrometer or other measuring instrument
6.1 Type inspection: Performance test of the prototype to determine whether the newly designed or trial-produced mechanical seal can achieve the specified performance. Type testing must be carried out on the first product of each specification, the first product after transfer to another factory, or the first product after major structural modifications.
Factory inspection: For mass-produced products, at least one set of each specification should be selected for factory inspection in each batch. 6.2
Special requirements shall be agreed upon separately.
6.3 Mechanical seal type inspection and factory inspection shall include static pressure test and operation test. 7
Marking and packaging
7.1. The manufacturer's logo shall be printed on the product in an obvious position that does not affect installation and use. 7.2 Each set of products in the packaging box (box) shall have a certificate of conformity, which shall include the product model, quantity, manufacturer name, signature and date of the inspection department and inspector.
7.3 The packaging box (box) shall contain technical documents such as instruction manual, packing list, spare parts list, etc. The words "handle with care" shall be marked on the outside of the box. 7.4 Product packaging shall be able to prevent damage and loss during transportation and storage. CB*3345—88
Appendix A
Contents and format of test report on mechanical seal of marine pump shaft (reference)
A1 Test report on mechanical seal of marine pump shaft Manufacturer:
Product model:
Test instrument
Measurement content
Accuracy
Medium name
Medium name
Test pressure
Production time:
Medium temperature
Test time
Relationship between leakage and time in mechanical seal operation test2 Each set of products in the packaging box (box) should have a certificate of conformity, which should include the product model, quantity, manufacturer name, inspection department and inspection personnel's signature and date.
7.3 The packaging box (box) should contain technical documents such as instruction manual, packing list, spare parts list, etc. The outside of the box should be marked with words such as "handle with care". 7.4 Product packaging should be able to prevent damage and loss during transportation and storage. CB*3345—88
Appendix A
Contents and format of test report on mechanical seal of marine pump shaft (reference)
A1 Test report on mechanical seal of marine pump shaft Manufacturer:
Product model:
Test instrument
Measurement content
Accuracy
Medium name
Medium name
Test pressure
Production time:
Medium temperature
Test time
Relationship between leakage and time in mechanical seal operation test2 Each set of products in the packaging box (box) should have a certificate of conformity, which should include the product model, quantity, manufacturer name, inspection department and inspection personnel's signature and date.
7.3 The packaging box (box) should contain technical documents such as instruction manual, packing list, spare parts list, etc. The outside of the box should be marked with words such as "handle with care". 7.4 Product packaging should be able to prevent damage and loss during transportation and storage. CB*3345—88
Appendix A
Contents and format of test report on mechanical seal of marine pump shaft (reference)
A1 Test report on mechanical seal of marine pump shaft Manufacturer:
Product model:
Test instrument
Measurement content
Accuracy
Medium name
Medium name
Test pressure
Production time:
Medium temperature
Test time
Relationship between leakage and time in mechanical seal operation test
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