A combined floating packing sealing structure for a gear pump for discharging melt from the bottom of a kettle

Abstract

The present invention discloses a combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle, which aims to solve the problem that the concentricity between the sealing packing and the gear sleeve of the gear pump is difficult to control, resulting in easy wear of the sealing packing and shortening the service life of the sealing packing. The invention comprises a sealing box body and a floating seal assembly, wherein a connecting hole is arranged in the sealing box body; the floating seal assembly is sheathed together with the sleeve, and the floating seal assembly comprises a floating packing box, a bellows, and a spiral floating ring; the spiral floating ring is sheathed between the sleeve and the floating packing box, and a liquid-passing spiral groove is arranged on the inner wall of the spiral floating ring, and floating gaps are arranged between the inner wall of the spiral floating ring and the outer wall of the sleeve, and between the outer wall of the spiral floating ring and the inner wall of the floating packing box; the floating packing box is provided with a liquid inlet and a liquid outlet connected with the floating gap; both sides of the spiral floating ring on the sleeve are sealed with packing rings; the floating packing box and the sealing box body are connected together, and the floating packing box can float radially.

Description

Technical Field

[0001] The invention relates to a melt gear pump structure, and more specifically to a combined floating packing sealing structure of a melt discharging gear pump at the bottom of a kettle. Background Art

[0002] The sealing methods of the melt discharge gear pump at the bottom of the kettle are usually spiral packing seal, mechanical seal and magnetic fluid seal. For the spiral packing seal, since the high-pressure melt discharge gear pump adopts dynamic pressure sliding bearing, it can be known from the basic principle of dynamic pressure sliding bearing that the gear shaft and the sliding bearing are not concentric, and at the same time, the spiral packing seal and the gear shaft are not concentric; the degree of non-concentricity will increase synchronously with the wear of the gear shaft and the bearing. The non-concentricity between the spiral packing seal and the gear shaft leads to eccentric wear of the packing, and the gap between the packing and the gear shaft increases, causing the packing seal to fail. At the same time, the excessive gap between the spiral and the gear shaft will also cause the spiral seal to fail; causing external air to leak into the gear pump cavity. On the one hand, the air entering the pump cavity will affect the feeding of the gear pump, resulting in the gear pump being unable to discharge stably and unable to work normally; on the other hand, it may cause material degeneration; furthermore, it will destroy the continuity and stability of the dynamic pressure sliding bearing oil film and damage the gear pump. The melt in the gear pump seal cavity will solidify after precooling, and solid particles entering the seal surface will cause the mechanical seal to fail; the speed of the melt discharge gear pump is very low, and the mechanical seal needs to be equipped with a separate lubrication and cooling system, which is not only expensive but also unstable in operation. Mechanical seals are rarely used in melt discharge gear pumps. Magnetic fluid seals are leak-free, wear-free, and pollution-free, but the cost is too high and they are also not suitable for high-temperature working environments. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings, the present invention provides a combined floating packing sealing structure for a bottom melt discharging gear pump, which can maintain the concentricity of the sealing packing and the gear shaft sleeve within the required range, slow down the wear of the sealing packing, and extend the service life of the sealing packing.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: a combined floating packing sealing structure of a bottom melt discharging gear pump, comprising a sealing box body and a floating sealing assembly, wherein a connecting hole is arranged in the sealing box body, the connecting hole is adapted to be equipped with a shaft sleeve for connecting a gear shaft, a medium spiral groove is arranged on the inner wall of the connecting hole, and the shaft sleeve rotates so that the melt leaked from the gear pump into the medium spiral groove is reversely pushed back into the gear pump under the spiral pushing action of the medium spiral groove; the floating sealing assembly is sheathed together with the shaft sleeve, and the floating sealing assembly comprises a floating stuffing box, a bellows, and a spiral floating ring; the spiral floating ring is sheathed A liquid-passing spiral groove is provided on the inner wall of the spiral floating ring between the shaft sleeve and the floating stuffing box, and floating gaps are provided between the inner wall of the spiral floating ring and the outer wall of the shaft sleeve, as well as between the outer wall of the spiral floating ring and the inner wall of the floating stuffing box; a liquid inlet and a liquid outlet connected to the floating gap are provided on the floating stuffing box; both sides of the spiral floating ring on the shaft sleeve are sealed with packing rings, and the packing rings are placed in the floating stuffing box; a bellows sleeve is arranged outside the floating stuffing box, one end of the bellows is tightly connected to the floating stuffing box, and the other end is tightly connected to the sealing box body; the floating stuffing box and the sealing box body are connected together, and the floating stuffing box can float radially.

[0005] The setting of the medium spiral groove makes the high-pressure melt leaking from the gear pump produce axial movement during the rotation of the sleeve and the gear shaft, generating a reverse push force on the melt, prompting the melt to continuously return to the inlet of the gear pump. The sealing liquid is introduced into the floating gap through the liquid inlet. During the rotation of the sleeve, the sealing liquid is pushed to the atmospheric side of the liquid outlet under the spiral push action of the liquid spiral groove, preventing air from entering the gear pump through the connecting hole. Since the medium spiral groove in the spiral sealing section will generate a large driving force during the rotation of the sleeve, and the direction of this driving force is toward the inside of the gear pump, it will generate a large suction force on the external air. Through the setting of the floating seal assembly, the flow of the sealing liquid blocks the external air from entering the connecting hole, thereby preventing the external air from leaking into the gear pump. The bellows can block the external air from entering the connecting hole from the connection position of the floating stuffing box and the sealing box body. The spiral floating ring produces a pumping effect on the sealing liquid when the sleeve rotates, realizing the external circulation of the sealing liquid, which can not only flush the sealing cavity, maintain the sealing cavity clean, and ensure the sealing effect; but also enhance the lubrication and cooling effect of the sealing packing.

[0006] The pumping effect of the spiral floating ring increases the circulation volume of the sealing liquid, enhances the lubrication and cooling effect of the sealing packing, and prolongs the service life of the seal; it also has a flushing effect on the sealing cavity, preventing solid particles from clogging the spiral groove for liquid flow and preventing solid particles from wearing the sealing packing. Since a floating gap is set and the floating stuffing box can float radially, during the rotation of the sleeve, the floating stuffing box and the spiral floating ring can float radially, reducing the eccentricity between the sleeve and the floating stuffing box, and ensuring that the sleeve and the floating stuffing box are as concentric as possible; even if the spiral floating ring contacts the sleeve, the spiral floating ring can play a supporting role, supporting the floating stuffing box, and the force is very slight.

[0007] The combined floating packing seal structure of the melt discharge gear pump at the bottom of the kettle can maintain the concentricity of the packing and the gear shaft sleeve within the required range, slow down the wear of the packing and extend the service life of the packing. The spiral floating ring seal is both a non-contact seal and a dynamic seal. There is no wear during operation, which not only improves the sealing effect, but also extends the service life of the seal.

[0008] Preferably, a positioning hole is provided on the floating stuffing box, a connecting rod is mounted on the positioning hole, the connecting rod is tightly connected to the sealing box body, a positioning block is provided at the end of the connecting rod, the positioning block abuts against the floating stuffing box, and a floating spacing is provided between the outer wall of the connecting rod and the connecting hole. This structural setting ensures a reliable connection between the floating stuffing box and the sealing box body, and ensures that the floating stuffing box can float radially.

[0009] Preferably, a cooling ring cavity is provided in the sealing box body, and a liquid inlet hole and a liquid outlet hole communicating with the cooling ring cavity are provided on the sealing box body.

[0010] When the equipment is repaired, coolant is introduced into the cooling ring cavity to cool the sealing box body, thereby freezing the melt to prevent it from leaking out. At the same time, the gap between the outer wall of the sleeve and the inner wall of the connecting hole can be fine-tuned by adjusting the temperature of the cooling medium. If the gap is too large, the spiral seal will fail.

[0011] As a preferred embodiment, one end of the floating stuffing box is connected to a stuffing gland, and the stuffing gland abuts against a stuffing ring on one side of the spiral floating ring. The stuffing gland plays a good positioning role for the stuffing ring.

[0012] As a preferred embodiment, bolts are connected between the packing gland and the floating packing box, and a butterfly spring is sleeved on the bolts. The butterfly spring abuts against the packing gland to provide pre-tightening force for the packing gland. The packing gland and the floating packing box are reliably connected, and the butterfly spring provides reliable pre-tightening force for the packing gland.

[0013] Preferably, an inwardly extending extension ring is provided at one end of the floating stuffing box, the extension ring is fitted with the end face of the sealing box body, and a gap is provided between the inner wall of the extension ring and the outer wall of the sleeve. The provision of the extension ring improves the sealing effect after the floating stuffing box and the sealing box body are fitted.

[0014] Preferably, an anti-rotation pin is installed between the spiral floating ring and the floating stuffing box. The anti-rotation pin can prevent the spiral floating ring from rotating relative to the floating stuffing box and prevent the sealing liquid from circulating inside the floating stuffing box.

[0015] Preferably, a sealing ring is installed between the outer wall of the spiral floating ring and the inner wall of the floating stuffing box. The arrangement of the sealing ring ensures that the sealing liquid can flow from one end of the liquid-passing spiral groove to the other end.

[0016] Preferably, a plurality of liquid-passing grooves are provided on both end surfaces of the spiral floating ring, which facilitate the flow of the sealing liquid between the inner wall and the outer wall of the spiral floating ring.

[0017] Preferably, sliding bearings are provided inside the gear pump and on the gear shaft respectively, the gear shaft and the sliding bearing are sleeved together, a flow groove is provided on the inner wall of the sliding bearing, and an annular groove is provided between the part between the sliding bearing and the sleeve on the gear shaft and the gear pump.

[0018] The melt in the gear pump flows into the through-flow groove to cool the sliding bearing, and then is sent into the ring groove and then flows into the medium spiral groove. During the rotation of the sleeve and the gear shaft, the medium spiral groove generates a reverse pushing force on the melt, prompting the melt to continuously return to the gear pump inlet.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The combined floating packing seal structure of the melt discharge gear pump at the bottom of the kettle can maintain the concentricity of the sealing packing and the gear shaft sleeve within the required range, reduce the wear of the sealing packing, and extend the service life of the sealing packing; (2) The spiral floating ring seal is both a non-contact seal and a dynamic seal, and there is no wear during operation, which not only improves the sealing effect but also extends the service life of the seal; (3) Since the medium spiral groove in the spiral sealing section will generate a large driving force during the rotation of the sleeve, the direction of this driving force is toward the inside of the gear pump, so it will generate a large suction force on the external air. Through the setting of the floating seal component, the flow of the sealing liquid blocks the external air from entering the connecting hole, thereby preventing the external air from leaking into the gear pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the installation state of the present invention;

[0021] Figure 2 is a cross-sectional view of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the spiral floating ring of the present invention;

[0023] In the figure: 1. sealing box body, 2. connecting hole, 3. gear shaft, 4. sleeve, 5. medium spiral groove, 6. gear pump, 7. cooling ring cavity, 8. floating stuffing box, 9. bellows, 10. spiral floating ring, 11. liquid spiral groove, 12. floating gap, 13. liquid inlet, 14. liquid outlet, 15. packing ring, 16. metal ring, 17. positioning hole, 18. connecting rod, 19. positioning block, 20. floating gap, 21. packing gland, 22. butterfly spring, 23. cover plate, 24. extension ring, 25. connecting ring, 26. gasket, 27. anti-rotation pin, 28. sealing ring, 29. liquid groove, 30. ring groove, 31. connecting key, 32. shaft shoulder, 33. sliding bearing, 34. flow groove. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0025] Embodiment: A combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle (see attached Figure 1 To Attachment Figure 3 ), including a sealing box body 1 and a floating sealing assembly. A connecting hole 2 is provided in the sealing box body. The connecting hole is adapted to be equipped with a sleeve 4 for connecting the gear shaft 3. A medium spiral groove 5 is provided on the inner wall of the connecting hole. The sleeve rotates so that the melt leaked from the gear pump 6 into the medium spiral groove is reversely pushed back into the gear pump under the spiral pushing action of the medium spiral groove. A cooling ring cavity 7 is provided in the sealing box body. A liquid inlet and a liquid outlet connected to the cooling ring cavity are provided on the sealing box body. The floating sealing assembly is sheathed with the sleeve. The floating sealing assembly includes a floating stuffing box 8, a bellows 9, and a spiral floating ring 10. The spiral floating ring is sheathed between the sleeve and the floating stuffing box. A liquid spiral groove 11 is provided on the inner wall of the spiral floating ring. A floating gap 12 is provided between the inner wall of the spiral floating ring and the outer wall of the sleeve, and between the outer wall of the spiral floating ring and the inner wall of the floating stuffing box. A liquid inlet 13 and a liquid outlet 14 connected to the floating gap are provided on the floating stuffing box. The liquid inlet is provided at the bottom of the floating stuffing box, and the liquid outlet is provided at the top of the floating stuffing box. Both sides of the spiral floating ring on the shaft sleeve are sealed with carbon fiber packing rings 15, which are placed in the floating stuffing box; metal rings 16 are installed between the two ends of the spiral floating ring and the packing rings. The bellows sleeve is set outside the floating stuffing box, one end of the bellows is tightly connected to the floating stuffing box, and the other end is tightly connected to the sealing box body; the floating stuffing box and the sealing box body are connected together, and the floating stuffing box can float radially.

[0026] The floating stuffing box is provided with a positioning hole 17, and a connecting rod 18 is mounted on the positioning hole. The connecting rod is tightly connected to the sealing box body. A positioning block 19 is provided at the end of the connecting rod, and the positioning block abuts on the floating stuffing box. A floating spacing 20 is provided between the outer wall of the connecting rod and the connecting hole. One end of the floating stuffing box is connected to a packing gland 21, and the packing gland abuts on the packing ring on one side of the spiral floating ring. Bolts are connected between the packing gland and the floating stuffing box, and a butterfly spring 22 is sleeved on the bolt. The butterfly spring abuts on the packing gland to provide pre-tightening force for the packing gland. One end of the floating stuffing box is tightly connected to a cover plate 23, and a number of positioning holes are evenly arranged on the cover plate. The packing gland and the cover plate on the floating stuffing box are tightly connected. The cover plate and the floating stuffing box are welded together. One end of the floating stuffing box is provided with an inwardly extending extension ring 24, which fits the end face of the sealing box body, and a gap is provided between the inner wall of the extension ring and the outer wall of the shaft sleeve. Connecting rings 25 are provided at both ends of the bellows, one connecting ring is welded to the outer wall of the floating stuffing box, and the other connecting ring is fastened to the end face of the sealing box body, and a gasket 26 is installed between the connecting ring and the sealing box body.

[0027] An anti-rotation pin 27 is installed between the spiral floating ring and the floating stuffing box. A sealing ring 28 made of polytetrafluoroethylene is installed between the outer wall of the spiral floating ring and the inner wall of the floating stuffing box. A number of evenly distributed liquid grooves 29 are provided on both end surfaces of the spiral floating ring. The sealing liquid is fed from the liquid inlet into the liquid groove at one end of the spiral floating ring and then enters the liquid spiral groove. The sealing liquid is then transported along the spiral direction of the liquid spiral groove, and then is sent out from the liquid groove at the other end of the spiral floating ring and discharged outward through the liquid outlet.

[0028] Sliding bearings 33 are provided in the gear pump and on the gear shaft, and the gear shaft and the sliding bearing are sleeved together. A through-flow groove 34 is provided on the inner wall of the sliding bearing, and an annular groove 30 is provided between the part between the sliding bearing and the sleeve on the gear shaft and the gear pump. A connecting key 31 is installed between the gear shaft and the sleeve. A shoulder 32 is provided on the front part of the sleeve on the gear shaft. The sealing box body is tightly installed on the gear pump, and gaskets are installed between the end face of the sealing box body and the gear pump, and between the end face of the sleeve and the shoulder. The gear shaft sleeved together with the sleeve is inserted into the gear pump and sleeved together with the sliding bearing in the gear pump.

[0029] The setting of the medium spiral groove makes the high-pressure melt leaking from the gear pump produce axial movement during the rotation of the sleeve and the gear shaft, generating a reverse push force on the melt, prompting the melt to continuously return to the inlet of the gear pump. The sealing liquid is introduced into the floating gap through the liquid inlet. During the rotation of the sleeve, the sealing liquid is pushed to the atmospheric side of the liquid outlet under the spiral push action of the liquid spiral groove, preventing air from entering the gear pump through the connecting hole. Since the medium spiral groove in the spiral sealing section will generate a large driving force during the rotation of the sleeve, and the direction of this driving force is toward the inside of the gear pump, it will generate a large suction force on the external air. Through the setting of the floating seal assembly, the flow of the sealing liquid blocks the external air from entering the connecting hole, thereby preventing the external air from leaking into the gear pump. The bellows can block the external air from entering the connecting hole from the connection position of the floating stuffing box and the sealing box body. The spiral floating ring produces a pumping effect on the sealing liquid when the sleeve rotates, realizing the external circulation of the sealing liquid, which can not only flush the sealing cavity, maintain the sealing cavity clean, and ensure the sealing effect; but also enhance the lubrication and cooling effect of the sealing packing.

[0030] The pumping effect of the spiral floating ring increases the circulation volume of the sealing liquid, enhances the lubrication and cooling effect of the sealing packing, and prolongs the service life of the seal; it also has a flushing effect on the sealing cavity, preventing solid particles from clogging the spiral groove for liquid flow and preventing solid particles from wearing the sealing packing. Since a floating gap is set and the floating stuffing box can float radially, during the rotation of the sleeve, the floating stuffing box and the spiral floating ring can float radially, reducing the eccentricity between the sleeve and the floating stuffing box, and ensuring that the sleeve and the floating stuffing box are as concentric as possible; even if the spiral floating ring contacts the sleeve, the spiral floating ring can play a supporting role, supporting the floating stuffing box, and the force is very slight.

[0031] The floating packing seal structure of the melt discharge gear pump at the bottom of the kettle can maintain the concentricity of the packing and the gear sleeve within the required range, slow down the wear of the packing and extend the service life of the packing. The spiral floating ring seal is both a non-contact seal and a dynamic seal. There is no wear during operation, which not only improves the sealing effect, but also extends the service life of the seal.

[0032] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle, characterized in that: It includes a sealing box body and a floating sealing assembly. A connecting hole is arranged in the sealing box body. The connecting hole is adapted to be equipped with a sleeve for connecting the gear shaft. A medium spiral groove is arranged on the inner wall of the connecting hole. When the sleeve rotates, the melt leaked from the gear pump into the medium spiral groove is pushed back into the gear pump under the spiral pushing action of the medium spiral groove. The floating sealing assembly is sheathed together with the sleeve. The floating sealing assembly includes a floating stuffing box, a bellows, and a spiral floating ring. The spiral floating ring is sheathed between the sleeve and the floating stuffing box. A liquid-passing spiral groove is arranged on the inner wall of the spiral floating ring. There are spiral grooves between the inner wall of the spiral floating ring and the outer wall of the sleeve, and between the outer wall of the spiral floating ring and the floating stuffing box. There are floating gaps between the inner walls; the floating stuffing box is provided with a liquid inlet and a liquid outlet connected to the floating gap; both sides of the spiral floating ring on the shaft sleeve are sealed with packing rings, and the packing rings are placed in the floating stuffing box; the bellows is sleeved outside the floating stuffing box, one end of the bellows is tightly connected to the floating stuffing box, and the other end is tightly connected to the sealing box body; the floating stuffing box and the sealing box body are connected together, and the floating stuffing box can float radially; one end of the floating stuffing box is connected to the stuffing gland; the stuffing gland and the floating stuffing box are connected by bolts, and a butterfly spring is sleeved on the bolts, and the butterfly spring abuts against the stuffing gland to provide pre-tightening force for the stuffing gland.

2. The combined floating packing seal structure of the gear pump for discharging melt from the bottom of a kettle according to claim 1 is characterized in that: The floating stuffing box is provided with a positioning hole, a connecting rod is mounted on the positioning hole, the connecting rod is fastened to the sealing box body, a positioning block is provided at the end of the connecting rod, the positioning block abuts against the floating stuffing box, and a floating spacing is provided between the outer wall of the connecting rod and the connecting hole.

3. The combined floating packing seal structure of the gear pump for discharging melt from the bottom of a kettle according to claim 1 is characterized in that: A cooling ring cavity is arranged in the sealing box body, and a liquid inlet hole and a liquid outlet hole which are communicated with the cooling ring cavity are arranged on the sealing box body.

4. The combined floating packing seal structure of the gear pump for discharging melt from the bottom of a kettle according to claim 1 is characterized in that: The packing gland abuts against the packing ring on one side of the spiral floating ring.

5. The combined floating packing seal structure of the gear pump for discharging melt from the bottom of a kettle according to claim 1 is characterized in that: An inwardly extending extension ring is arranged at one end of the floating stuffing box, the extension ring is fitted with the end surface of the sealing box body, and a gap is arranged between the inner wall of the extension ring and the outer wall of the shaft sleeve.

6. The combined floating packing seal structure of the gear pump for discharging melt from the bottom of a kettle according to claim 1 is characterized in that: An anti-rotation pin is installed between the spiral floating ring and the floating stuffing box.

7. A combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle according to any one of claims 1 to 6, characterized in that: A sealing ring is installed between the outer wall of the spiral floating ring and the inner wall of the floating stuffing box.

8. A combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle according to any one of claims 1 to 6, characterized in that: A plurality of liquid passage grooves are arranged on both end surfaces of the spiral floating ring.

9. A combined floating packing seal structure for a gear pump for discharging melt from the bottom of a kettle according to any one of claims 1 to 6, characterized in that: Sliding bearings are arranged inside the gear pump and on the gear shaft respectively. The gear shaft and the sliding bearing are sheathed together. A through-flow groove is arranged on the inner wall of the sliding bearing. An annular groove is arranged between the part between the sliding bearing and the shaft sleeve on the gear shaft and the gear pump.

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