Mechanical seal for vehicle-mounted fire pump
By using a combination of sealing seat, sleeve, moving ring, static ring, elastic element and slip sealing ring in the mechanical seal of the vehicle-mounted fire pump, the problem of sealing leakage caused by large atmospheric pressure is solved, and the effective sealing performance of the sealing end surface is achieved.
Patent Information
- Application Number
- CN202421033135.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-13
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-05-13
AI Technical Summary
Conventional mechanical seal design fails to effectively consider the large atmospheric pressure, resulting in the sealing end surface being easily leaked when used by vehicle-mounted fire pumps, which cannot guarantee sealing performance.
A mechanical seal for on-board fire pump is designed, using a combination of sealing seat, sleeve, moving ring, static ring, elastic element and sliding sealing ring. By adjusting the balance diameter and load coefficient of the static ring and sealing seat, it adapts to the change of pressure direction and enhances the sealing performance of the sealing end surface.
By reducing the balance diameter of the mechanical seal during vacuum extraction, increasing the load coefficient, so that atmospheric pressure can more effectively promote the closure of the seal end face, solving the problem of stress when the pressure direction changes, and ensuring the sealing performance of the seal end face.
Smart Images
Figure CN222759978U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of mechanical seals, in particular to a mechanical seal for a vehicle-mounted fire pump. Background Art
[0002] Fire trucks are usually equipped with on-board fire pumps to pressurize liquid fire extinguishing agents such as water and foam solutions. During the startup of the on-board fire pump, the pressure direction will change: after the fire pump is started, there is a vacuum stage, and the maximum vacuum degree is about 90kPa. At this time, the pressure on the atmospheric side of the mechanical seal is greater than the medium side; after the liquid fire extinguishing agent is sucked into the fire pump and contacts the mechanical seal, the medium pressure is about 1.0MPa. At this time, the pressure on the medium side of the mechanical seal is greater than the atmospheric side. Conventional mechanical seals are often designed only to consider the situation where there is a large pressure on the medium side. When the mechanical seal is in a state of high atmospheric pressure for a long time during the use of the on-board fire pump, the conventionally designed mechanical seal is prone to leakage and cannot guarantee the sealing performance of the sealing end face. Utility Model Content
[0003] Aiming at the problem that the conventional mechanical seal design fails to take into account the high pressure on the atmospheric side, resulting in a high risk of damage when the vehicle-mounted fire pump is used, the utility model provides a mechanical seal for a vehicle-mounted fire pump.
[0004] The utility model provides the following technical solution: a mechanical seal for a vehicle-mounted fire pump, comprising a sealing seat and a shaft sleeve rotatably connected to the sealing seat, the shaft sleeve being provided with a dynamic ring, the sealing seat being slidably connected with a static ring, an elastic element being further provided between the static ring and the sealing seat, the static ring inner wall and the sealing seat outer wall being provided with annular grooves, the two annular grooves forming a sealing ring installation groove, a sliding sealing ring being provided in the sealing ring installation groove, the outer diameter of the sealing ring installation groove being smaller than the outer diameter of the sealing end face, the outer diameter of the sealing ring installation groove being larger than the inner diameter of the sealing end face, and the inner diameter of the sealing ring installation groove being smaller than the inner diameter of the sealing end face.
[0005] Preferably, the sliding seal ring is an O-ring, and the length of the seal ring installation groove in the axial direction of the sleeve is at least twice the diameter of the sliding seal ring.
[0006] Preferably, the shaft sleeve is provided with a lug extending toward the movable ring, and the movable ring is provided with a keyway cooperating with the lug.
[0007] Preferably, a gasket and a sealing ring are further provided between the shaft sleeve and the moving ring.
[0008] Preferably, an anti-rotation pin is provided between the sealing seat and the stationary ring.
[0009] The beneficial effects of the utility model are: reducing the balance diameter of the mechanical seal during vacuuming, increasing the load coefficient, allowing the atmospheric pressure to play a greater role in promoting the closure of the sealing end face, solving the force problem of the sealing end face when the pressure direction on both sides of the mechanical seal changes, so as to ensure that the sealing end face does not leak. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 It is a cross-sectional view of an embodiment of the utility model.
[0011] Figure 2 It is a schematic diagram of the atmospheric pressure of an embodiment when evacuating a vacuum.
[0012] Figure 3 The figure is a schematic diagram of the medium pressure of an embodiment when the medium is pumped.
[0013] Figure numerals: 11, sealing seat; 12, static ring; 13, elastic element; 14, sealing ring mounting groove; 15, sliding sealing ring; 21, shaft sleeve; 22, dynamic ring; 23, lug; 24, gasket; 25, sealing ring. DETAILED DESCRIPTION
[0014] The following is a more detailed description of the implementation of the utility model in conjunction with the drawings and the figure marks, so that those skilled in the art can implement it after reading this specification. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not used to limit the utility model.
[0015] The utility model provides Figure 1 The mechanical seal for a vehicle-mounted fire pump shown in the figure comprises a sealing seat 11 and a sleeve 21. The sealing seat 11 is bolted to the pump body, and the sleeve 21 is bolted to the pump shaft. Sealing rings are arranged between the sealing seat and the pump body, and between the sleeve 21 and the pump shaft to improve the sealing performance. The sealing seat 11 is slidably connected with a stationary ring 12, and an anti-rotation pin is arranged between the two to prevent the stationary ring 12 from rotating. The sleeve 21 is rotatably connected to the sealing seat 11, and the sleeve 21 is provided with a dynamic ring 22. A gasket 24 and a sealing ring 25 are arranged between the two. The gasket 24 plays a buffering role, and the sealing ring 25 prevents medium leakage; the sleeve 21 is provided with a lug 23 extending toward the dynamic ring 22, and the dynamic ring 22 is provided with a keyway matched with the lug 23. The sleeve 21 transmits torque to the dynamic ring 22 through the lug 23. The stationary ring 12 and the dynamic ring 22 form a friction pair, and the end faces of the two contacting each other are sealing end faces. An elastic element 13 is also provided between the stationary ring 12 and the sealing seat 11. The elastic element 13 is generally a spring, which squeezes the stationary ring 12 toward the dynamic ring 22 to provide compensation when the sealing end surface is worn.
[0016] In this embodiment, the inner wall of the stationary ring 12 and the outer wall of the sealing seat 11 are both provided with annular grooves, and the two annular grooves enclose a sealing ring installation groove 14, and a sliding sealing ring 15 is provided in the sealing ring installation groove 14. When the pressure direction on both sides of the mechanical seal changes during the startup of the vehicle-mounted fire pump, the balance diameter and load coefficient of the stationary ring are changed to adapt to the pressure change. Specifically, the outer diameter d4 of the sealing ring installation groove 14 is smaller than the outer diameter d2 of the sealing end surface, and the outer diameter d4 of the sealing ring installation groove 14 is larger than the inner diameter d1 of the sealing end surface, and the inner diameter d3 of the sealing ring installation groove 14 is smaller than the inner diameter d1 of the sealing end surface.
[0017] Please refer to Figure 2-3 The left side of the mechanical seal is the atmospheric side, and the right side is the medium side. When the vehicle-mounted fire pump is started, there are two stages: vacuuming and medium extraction. When vacuuming, the pressure on the atmospheric side of the mechanical seal is greater than that on the medium side. The direction of atmospheric pressure transmission in the gaps between the components is as follows: Figure 2 As shown by the middle arrow, the sliding seal ring 15 is pushed to the left side of the seal ring installation groove 14 by the atmospheric pressure, and the static ring 12 also moves to the left under the pressure of the elastic element. At this time, the balance diameter of the mechanical seal is the inner diameter d3 of the seal ring installation groove 14, and its load coefficient When it is greater than 1, the atmospheric pressure will be more involved in the stress state of closing the sealing end face, so as to ensure that the sealing end face does not leak at this stage. The load coefficient calculation formula is:
[0018]
[0019] When pumping the medium, the pressure on the medium side of the mechanical seal is greater than that on the atmospheric side. The direction of medium pressure transmission is as follows: Figure 3 As shown by the arrow, the sliding seal ring 15 is pushed to the right side of the seal ring installation groove 14 by the medium pressure, and the static ring 12 is still to the left by the elastic pressure. At this time, the balance diameter of the mechanical seal is the outer diameter d4 of the seal ring installation groove 14, and its load coefficient Greater than 0 and less than 1 is the result of conventional design. The load factor calculation formula is:
[0020]
[0021] Furthermore, the sliding seal ring 15 is an O-ring, and the length of the seal ring mounting groove 14 in the axial direction of the sleeve is at least twice the diameter of the sliding seal ring 15. Its function is to ensure the axial floatability of the stationary ring and prevent the sliding seal ring 15 from being crushed between the metal end faces of the stationary ring and the seal ring mounting groove 14, thereby causing the dynamic and static rings to be crushed and the friction to increase.
[0022] The above are one or more embodiments of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.
Claims
1. A mechanical seal for a vehicle-mounted fire pump, comprising a sealing seat and a sleeve rotatably connected to the sealing seat, the sleeve being provided with a dynamic ring, the sealing seat being slidably connected with a static ring, an elastic element being further provided between the static ring and the sealing seat, characterized in that: The inner wall of the static ring and the outer wall of the sealing seat are both provided with annular grooves, and the two annular grooves form a sealing ring installation groove, in which a sliding sealing ring is arranged, the outer diameter of the sealing ring installation groove is smaller than the outer diameter of the sealing end face, the outer diameter of the sealing ring installation groove is larger than the inner diameter of the sealing end face, and the inner diameter of the sealing ring installation groove is smaller than the inner diameter of the sealing end face.
2. The mechanical seal for a vehicle-mounted fire pump according to claim 1, characterized in that: The sliding seal ring is an O-type seal ring, and the length of the seal ring installation groove in the axial direction of the sleeve is at least twice the diameter of the sliding seal ring.
3. The mechanical seal for a vehicle-mounted fire pump according to claim 1, characterized in that: The shaft sleeve is provided with a lug extending toward the movable ring, and the movable ring is provided with a keyway matched with the lug.
4. The mechanical seal for a vehicle-mounted fire pump according to claim 1, characterized in that: A gasket and a sealing ring are also arranged between the shaft sleeve and the moving ring.
5. The mechanical seal for a vehicle-mounted fire pump according to claim 1, characterized in that: An anti-rotation pin is arranged between the sealing seat and the stationary ring.