Packing sealing structure at high-pressure end of multi-stage centrifugal pump

Abstract

The utility model discloses a multi-stage centrifugal pump high-pressure end packing sealing structure which comprises a pump shaft, a shaft sleeve is sleeved outside the pump shaft, a packing culvert body is sleeved outside the shaft sleeve, one side of the packing culvert body is communicated with the inside of a pump, and the other side of the packing culvert body is connected with the shaft sleeve in a sealing mode. A packing ring a, a packing layer a, a packing ring b and a packing layer b are sequentially arranged in the packing cavity from the sealing side to the side close to the inside of the pump, a packing gland is arranged on the outer side of the packing layer b, a flushing hole is formed in the packing culvert body and corresponds to the packing ring b, one end of the flushing hole is communicated with the packing cavity, the other end of the flushing hole is connected with a flushing device through a flushing pipe, and a control valve and a pressure release valve are arranged on the flushing pipe. According to the utility model, the service life of the filler is prolonged, the maintenance frequency is reduced, the cost is reduced, and the safety of production operation is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of packing seals for multi-stage centrifugal pumps, in particular to a packing seal structure for a high-pressure end of a multi-stage centrifugal pump. Background Art

[0002] The multi-stage centrifugal pump used in rock salt mining in the salt chemical production process contains water-insoluble substances such as CaCO3 and MgOH in the brine medium. Therefore, the shaft seal device should not use mechanical seals, but packing seals. Packing seals refer to connecting the rope-shaped sealing material end to end and winding it around the pump shaft in circles to achieve the sealing effect. However, the current multi-stage centrifugal pump has a high sealing pressure at the high-pressure end. Since the packing wrapped on the shaft is in direct contact with the pump shaft, the high pressure causes the packing to wear more and consume faster, and the packing has a short service life. As a result, the equipment needs to be frequently inspected and replaced, which seriously affects the stable operation of the production system. On the other hand, because the packing seal cavity is in a high-pressure state, when the equipment is water-cooled, the high pressure in the cavity causes the cooling water to be unable to enter the packing cavity for cooling, and it will also cause the brine to flow back into the cooling pipe, causing the water cooling pipe to corrode and leak, which poses a great safety hazard to the production of the equipment. Utility Model Content

[0003] The utility model aims to provide a multistage centrifugal pump high-pressure end packing sealing structure, which solves the problems that the existing multistage centrifugal pump high-pressure end packing has a short service life and needs to be frequently replaced, and the pressure in the sealing cavity increases during cooling, affecting the cooling effect.

[0004] The technical solution adopted by the utility model is a packing seal structure at the high-pressure end of a multi-stage centrifugal pump, comprising a pump shaft, a shaft sleeve is sleeved on the outside of the pump shaft, a packing cage is sleeved on the outside of the shaft sleeve, one side of the packing cage is communicated with the inside of the pump, and the other side is sealed and connected with the shaft sleeve, a packing cavity is formed between the packing cage and the shaft sleeve, a packing ring a, a packing layer a, a packing ring b, and a packing layer b are sequentially arranged in the packing cavity from the sealing side to the side close to the inside of the pump, a packing gland is arranged on the outside of the packing layer b, a flushing hole is opened in the packing cage at the position corresponding to the packing ring b, one end of the flushing hole is communicated with the packing cavity, and the other end is connected to the flushing device through a flushing pipe, and a control valve and a pressure relief valve are arranged on the flushing pipe.

[0005] The utility model is also characterized in that:

[0006] Bolt holes are provided at corresponding positions of the packing gland and the packing cover body close to the inner side of the pump, and the packing gland and the packing cover body are connected with bolts.

[0007] One filler is arranged in the packing layer a, and three fillers are arranged in the packing layer b. Each of the fillers is connected end to end to form a ring.

[0008] The interface where the packing is connected from end to end is a 45° cut.

[0009] The cutout positions of two adjacent fillers in the packing layer b are staggered 180° around the axis.

[0010] The control valve is arranged near one end of the flushing hole, and a branch is arranged on the flushing pipe between the control valve and the flushing device to be connected to the ditch, and a pressure relief valve is arranged on the branch.

[0011] The flushing device is a flushing pump, and a flushing main valve is arranged at the water outlet end of the flushing pump.

[0012] The beneficial effects of the utility model are as follows: a packing sealing structure at the high-pressure end of a multi-stage centrifugal pump is provided, a packing cage is sleeved on the outside of the pump shaft, a packing cavity is formed between the shaft sleeve and the packing cage, and a packing ring is added at the bottom of the packing cavity to play the role of a pressure relief ring, thereby reducing the wear of the internal packing to maintain the long-term stable operation of the system, increasing the maintenance and overhaul cycle, and effectively reducing the operating cost; and a control valve and a pressure relief valve are provided on the flushing pipeline for pressure regulation, thereby solving the problem that the cooling water cannot enter the packing cavity due to the increased internal pressure, thereby ensuring the safe operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The utility model is a structural schematic diagram of a packing seal structure at the high-pressure end of a multi-stage centrifugal pump.

[0014] In the figure: 1. packing body, 2. packing ring a, 3. packing layer a, 4. packing ring b, 5. packing gland, 6. flushing hole, 7. control valve, 8. pressure relief valve, 9. pump shaft, 10. packing layer b. DETAILED DESCRIPTION

[0015] The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.

[0016] The utility model provides a multi-stage centrifugal pump high-pressure end packing seal structure, such as Figure 1As shown, it includes a pump shaft 9, a shaft sleeve is sleeved on the outside of the pump shaft 9, and a stuffing cage 1 is sleeved on the outside of the shaft sleeve, that is, the pump shaft 9 and the shaft sleeve penetrate from one side of the stuffing cage 1 along the axis and penetrate from the other side, one side of the stuffing cage 1 is connected with the inside of the pump, and the other side is sealed with the shaft sleeve, thereby forming a stuffing cavity between the stuffing cage 1 and the shaft sleeve, and a stuffing ring a2, a stuffing layer a3, a stuffing ring b4, and a stuffing layer b10 are sequentially arranged in the stuffing cavity from the sealing side to the side close to the inside of the pump, and the stuffing ring a2 is arranged at the bottom of the stuffing cage 1. Since there is a large pressure inside the high-pressure end of the multi-stage centrifugal pump during operation, the stuffing ring a2 is used as a pressure relief ring to reduce the pressure on the bottom stuffing, and the stuffing layer a3 and the stuffing layer b10 are separated by the stuffing ring b4, and the multi-layer stuffing structure effectively plays a sealing effect. A packing gland 5 is arranged outside the packing layer b10. The packing gland 5 can compact the packing in the packing cavity by a variety of fixing methods, such as tightening and fixing with the packing containment body 1 through a threaded port, or directly riveting with the packing containment body 1 through physical extrusion. Bolt holes can also be provided at the corresponding positions of the packing gland 5 and the packing containment body 1 near the inner side of the pump, and the packing gland 5 and the packing containment body 1 are fixedly connected by bolts. The packing containment body 1 is provided with a flushing hole 6 at the position corresponding to the packing ring b4. One end of the flushing hole 6 is connected to the packing cavity, and the other end is connected to the flushing device through a flushing pipe. The flushing device can use flushing liquid and coolant to cool and flush the packing cavity to prevent the packing from high temperature or salt formation. The flushing device can be a flushing pump, and a flushing main valve is provided at the outlet of the flushing pump for overall control. A control valve 7 and a pressure relief valve 8 are provided on the flushing pipe. When the cooling water pressure is too low or the pressure in the packing cavity increases so that the cooling water cannot enter the packing cavity, the pressure can be regulated by opening the control valve 7 and the pressure relief valve 8 to ensure the normal operation of the cooling and flushing system. The specific setting method of the control valve 7 and the pressure relief valve 8 is to set the control valve 7 on the pipeline near one end of the flushing hole 6, and set a branch on the flushing pipe between the control valve 7 and the flushing device to connect to the ditch, and set the pressure relief valve 8 on the branch. This structure can perform normal flushing and cooling work by opening the control valve 7 and the main flushing valve when the pressure relief valve 8 is closed. When pressure regulation is required, the pressure relief valve 8 is opened to relieve pressure, which is more convenient and flexible to use.

[0017] In addition, in the above structure, a filler is usually set in the packing layer a3. The filler made of quadrangular aramid carbon fiber is more suitable for the bottom high-pressure environment. Three high-water-based fillers are set in the packing layer b10. The thickness of each filler should be about 1 mm larger than the gap between the packing cover 1 and the shaft kit to ensure the sealing effect. The packing is installed end to end to form a ring, and a 45° incision is used at the interface. The advantage of this is that the packing interface is more firm and not easy to deform. The incision positions of two adjacent packings in the packing layer b10 are staggered 180° around the axis of the pump shaft to achieve a better sealing effect and prevent leakage. The utility model provides a packing seal structure at the high-pressure end of a multi-stage centrifugal pump, and its working principle and effect are as follows: a packing ring a2 is installed at the bottom of the packing cavity between the packing culvert 1 and the shaft sleeve to relieve pressure and reduce the wear of the internal packing to maintain the long-term stable operation of the system; multiple layers of annular packing are filled in the packing layer a3 and the packing layer b10, and the outer side is compacted and fixed by a packing gland 5 to achieve a sealing effect; a flushing hole 6 is arranged at the packing ring b4 to flush and cool the inside of the packing cavity through a flushing device; a pressure relief valve 8 is introduced to relieve pressure when the internal pressure of the system increases and flushing becomes difficult, thereby ensuring the normal operation of the flushing system and preventing the problem of corrosion and leakage caused by the backflow of salt water into the flushing pipe.

[0018] The utility model structure is used to transform the packing seal of the brine mining pump in actual use. The maintenance period of the packing at the high-pressure end of the brine mining pump after the transformation is extended from less than one week to about 5 months, which greatly reduces the maintenance frequency of the brine mining pump, saves man-hour costs, improves the system operation efficiency, and ensures the production safety of the equipment.

[0019] Example 1

[0020] The packing seal structure at the high-pressure end of a multi-stage centrifugal pump provided in the present embodiment 1 comprises a pump shaft 9, a shaft sleeve is sleeved on the outside of the pump shaft 9, a packing cage 1 is sleeved on the outside of the shaft sleeve, one side of the packing cage 1 is connected to the inside of the pump, and the other side is sealed with the shaft sleeve, a packing cavity is formed between the packing cage 1 and the shaft sleeve, a packing ring a2, a packing layer a3, a packing ring b4, a packing layer b10 are sequentially arranged in the packing cavity from the sealing side to the side close to the inside of the pump, a packing gland 5 is arranged on the outside of the packing layer b10, a flushing hole 6 is provided in the packing cage 1 at a position corresponding to the packing ring b4, one end of the flushing hole 6 is connected to the packing cavity, and the other end is connected to the flushing device through a flushing pipe, and a control valve 7 and a pressure relief valve 8 are arranged on the flushing pipe.

[0021] The packing seal structure at the high-pressure end of the multi-stage centrifugal pump provided in this embodiment 1 adds a packing ring at the bottom of the packing culvert compared to the conventional packing seal structure, which plays a pressure relief role and increases the service life of the packing. The pressure relief valve and control valve on the flushing pipe can be opened when needed to reduce the pressure in the sealing chamber so that flushing cooling water can be introduced normally.

[0022] Example 2

[0023] The packing seal structure at the high-pressure end of the multi-stage centrifugal pump provided in the present embodiment 2 includes a pump shaft 9, a shaft sleeve is sleeved on the outside of the pump shaft 9, a packing hopper 1 is sleeved on the outside of the shaft sleeve, one side of the packing hopper 1 is connected to the inside of the pump, and the other side is sealed and connected to the shaft sleeve, a packing cavity is formed between the packing hopper 1 and the shaft sleeve, and a packing ring a2, a packing layer a3, a packing ring b4, and a packing layer b10 are sequentially arranged in the packing cavity from the sealing side to the side close to the inside of the pump, one packing is arranged in the packing layer a3, three packings are arranged in the packing layer b10, and each packing is connected end to end to form a ring The interface where the packing is connected end to end is a 45° incision. The incision positions of two adjacent packings in the packing layer b10 are staggered 180° around the axis. A packing gland 5 is arranged on the outside of the packing layer b10. Bolt holes are provided at the corresponding positions of the packing gland 5 and the packing containment body 1 close to the inner side of the pump. The packing gland 5 is connected to the packing containment body 1 with bolts. The packing containment body 1 is provided with a flushing hole 6 at the position corresponding to the packing ring b4. One end of the flushing hole 6 is connected to the packing cavity, and the other end is connected to the flushing device through a flushing pipe. A control valve 7 and a pressure relief valve 8 are provided on the flushing pipe.

[0024] The packing seal structure at the high-pressure end of the multi-stage centrifugal pump provided in this embodiment 2 uses bolts to fix the packing cover and the packing cover body on the basis of embodiment 1. The press-fit seal is tighter, and the packing ring interface is beveled and staggered, so the sealing effect is better.

[0025] Example 3

[0026] The invention comprises a pump shaft 9, a shaft sleeve is sleeved on the outside of the pump shaft 9, a stuffing cage 1 is sleeved on the outside of the shaft sleeve, one side of the stuffing cage 1 is communicated with the pump, and the other side is sealed with the shaft sleeve, a stuffing cavity is formed between the stuffing cage 1 and the shaft sleeve, a stuffing ring a2, a stuffing layer a3, a stuffing ring b4, a stuffing layer b10 are sequentially arranged in the stuffing cavity from the sealing side to the side close to the pump, a stuffing is arranged in the stuffing layer a3, three stuffings are arranged in the stuffing layer b10, each stuffing is connected end to end to form a ring, the interface where the stuffing is connected end to end is a 45° cut, the cut positions of two adjacent stuffings in the stuffing layer b10 are staggered 180° around the axis, and the stuffing is arranged in the packing layer a3. A packing gland 5 is arranged outside the material layer b10. Bolt holes are provided at corresponding positions of the packing gland 5 and the packing containment body 1 near the inner side of the pump. The packing gland 5 is connected to the packing containment body 1 with bolts. A flushing hole 6 is provided at the position corresponding to the packing ring b4 of the packing containment body 1. One end of the flushing hole 6 is connected to the packing cavity, and the other end is connected to the flushing device through a flushing pipe. A control valve 7 and a pressure relief valve 8 are provided on the flushing pipe. The control valve 7 is arranged at one end near the flushing hole 6. A branch is provided on the flushing pipe between the control valve 7 and the flushing device and connected to the ditch. A pressure relief valve 8 is provided on the branch. The flushing device is a flushing pump. A main flushing valve is provided at the water outlet of the flushing pump.

[0027] The packing seal structure at the high-pressure end of the multi-stage centrifugal pump provided in Example 3 has a flushing pipe with a branch pipe connected to the ditch, and a pressure relief valve is provided on the branch pipe. When there is no need to adjust the pressure, the pressure relief valve can remain closed without affecting the normal use of the flushing device. When the pressure is released, the pressure relief valve is opened to discharge the waste liquid into the ditch and release the pressure, so that the flushing system is more flexible and efficient to use.

Claims

1. The packing seal structure at the high-pressure end of a multistage centrifugal pump is characterized by: The invention comprises a pump shaft (9), wherein a shaft sleeve is sleeved on the outside of the pump shaft (9), and a stuffing cage (1) is sleeved on the outside of the shaft sleeve. One side of the stuffing cage (1) is connected to the inside of the pump, and the other side is sealed with the shaft sleeve. A stuffing cavity is formed between the stuffing cage (1) and the shaft sleeve. A stuffing ring a (2), a stuffing layer a (3), a stuffing ring b (4), and a stuffing layer b (10) are arranged in sequence in the stuffing cavity from the sealing side to the side close to the inside of the pump. A stuffing gland (5) is arranged on the outside of the stuffing layer b (10). A flushing hole (6) is provided on the stuffing cage (1) at a position corresponding to the stuffing ring b (4). One end of the flushing hole (6) is connected to the stuffing cavity, and the other end is connected to a flushing device through a flushing pipe. A control valve (7) and a pressure relief valve (8) are arranged on the flushing pipe.

2. The packing seal structure at the high-pressure end of a multistage centrifugal pump according to claim 1, characterized in that: Bolt holes are provided at corresponding positions of the packing gland (5) and the packing containment body (1) close to the inside of the pump, and the packing gland (5) and the packing containment body (1) are connected by bolts.

3. The packing seal structure at the high-pressure end of a multi-stage centrifugal pump according to claim 1, characterized in that: One filler is arranged in the packing layer a (3), and three fillers are arranged in the packing layer b (10), and each of the fillers is connected end to end to form a ring.

4. The packing seal structure at the high-pressure end of a multi-stage centrifugal pump according to claim 3 is characterized in that: The interface where the filler is connected end to end is a 45° cut.

5. The packing seal structure at the high-pressure end of a multi-stage centrifugal pump according to claim 4, characterized in that: The cutout positions of two adjacent fillers in the filler layer b (10) are staggered 180° around the axis.

6. The packing seal structure at the high pressure end of a multi-stage centrifugal pump according to claim 1, characterized in that: The control valve (7) is arranged near one end of the flushing hole (6), and a branch is arranged on the flushing pipe between the control valve (7) and the flushing device and connected to the ditch, and a pressure relief valve (8) is arranged on the branch.

7. The packing seal structure at the high-pressure end of a multi-stage centrifugal pump according to claim 6, characterized in that: The flushing device is a flushing pump, and a flushing main valve is arranged at the water outlet end of the flushing pump.

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