A vacuum pumping unit for a vacuum consumable furnace

Abstract

The utility model belongs to the field of nonferrous metal vacuum smelting equipment, and proposes a vacuum pumping unit for a vacuum consumable furnace, which is connected to the furnace body of the vacuum consumable furnace. The vacuum pumping unit includes a first vacuum pumping pipeline, and a slide valve mechanical pump group and a Roots pump group arranged on the first vacuum pumping pipeline. One end of the first vacuum pumping pipeline is connected to the furnace body, and the other end is emptied. The slide valve mechanical pump group is arranged on the first vacuum pumping pipeline and close to the emptied end, and the Roots pump group is arranged on the first vacuum pumping pipeline and close to the furnace body. Not only can different vacuum degrees be obtained to meet different process requirements, but also the ultimate vacuum degree of the slide valve mechanical pump group is greatly improved to ensure the stability of the production process.

Description

Technical Field

[0001] The utility model belongs to the field of nonferrous metal vacuum smelting equipment, in particular to a vacuum pumping unit for a vacuum consumable furnace. Background Art

[0002] With the development of vacuum smelting technology, vacuum preparation equipment is more and more widely used. When VAR furnace is used to smelt titanium and titanium alloy, due to the corrosive chlorine and dust impurities contained in the extracted gas, the GDQ-J rubber shaft seal series pneumatic high vacuum flapper valve used for switching pipeline functions often rubs against the valve stem nut during operation. The valve stem thread seal is easily contaminated by chlorine and dust impurities and the valve stem stroke is relatively long, which affects the sealing performance. In actual applications, there are two problems: First, the seal wears with the increase of the number of uses, and the seal leakage reduces the limit vacuum degree of the slide valve mechanical pump at the connection, and the vacuum degree required by the process is unstable. It is very difficult to pump the vacuum degree below 0.5pa before improvement, which affects the stability of the production process; on the other hand, the seal leakage reduces the limit vacuum degree of the slide valve mechanical pump at the connection, which prolongs the vacuum pumping time. It takes about 180 minutes to pump the vacuum to 1pa, which affects the production efficiency. Utility Model Content

[0003] In view of the above problems, the utility model proposes a vacuum pumping unit for a vacuum consumable furnace, which is connected to the furnace body of the vacuum consumable furnace. The vacuum pumping unit includes a first vacuum pumping pipeline, and a sliding valve mechanical pump group and a Roots pump group arranged on the first vacuum pumping pipeline. One end of the first vacuum pumping pipeline is connected to the furnace body, and the other end is emptied. The sliding valve mechanical pump group is arranged on the first vacuum pumping pipeline and close to the emptied end, and the Roots pump group is arranged on the first vacuum pumping pipeline and close to the furnace body.

[0004] Furthermore, the slide valve mechanical pump group includes at least two groups of slide valve mechanical pumps connected in parallel.

[0005] Furthermore, the Roots pump group includes a small Roots pump and a large Roots pump, the small Roots pump is arranged on the first vacuum pipeline and close to the slide valve mechanical pump group, and the large Roots pump is arranged on the first vacuum pipeline and close to the furnace body.

[0006] Furthermore, the vacuum pumping unit also includes a second vacuum pumping pipeline and an oil booster pump arranged on the second vacuum pumping pipeline. The two ends of the second vacuum pumping pipeline are respectively arranged on both sides of the large Roots pump and are connected to the first vacuum pumping pipeline. The oil booster pump is connected in parallel with the large Roots pump.

[0007] Furthermore, the vacuum pumping unit also includes a first high vacuum baffle valve arranged on the first vacuum pumping pipeline, and the first high vacuum baffle valve is arranged between the Roots pumping unit and the furnace body and is close to the Roots pumping unit.

[0008] Furthermore, the vacuum pumping unit also includes a second high vacuum baffle valve and a third high vacuum baffle valve arranged on the second vacuum pumping pipeline, the second high vacuum baffle valve is arranged on one side of the oil booster pump and close to the Roots pump group, and the third high vacuum baffle valve is arranged on the other side of the oil booster pump and close to the oil booster pump.

[0009] Furthermore, the vacuum pumping unit also includes a third vacuum pumping pipeline and a rotary vane pump arranged on the third vacuum pumping pipeline. One end of the third vacuum pumping pipeline is arranged between the oil booster pump and the second high vacuum baffle valve and is connected to the second vacuum pumping pipeline, and the other end is emptied.

[0010] Furthermore, the vacuum pumping unit also includes a fourth high vacuum baffle valve arranged on the third vacuum pumping pipeline, and the fourth high vacuum baffle valve is arranged between the end of the third vacuum pumping pipeline connected to the second vacuum pumping pipeline and the rotary vane pump.

[0011] Furthermore, a solenoid valve is arranged inside the slide valve mechanical pump.

[0012] Furthermore, the first vacuum pipeline between the slide valve mechanical pump unit and the Roots pump unit includes a bellows pipeline.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. This application adopts a sliding valve mechanical pump group and a Roots pump group to form a vacuum pumping unit for vacuum acquisition, which can not only obtain different vacuum degrees to meet different process requirements, but also greatly improve the ultimate vacuum degree of the sliding valve mechanical pump group to ensure the stability of the production process.

[0015] 2. The present application forms a sliding valve mechanical pump group by setting up at least two groups of sliding valve mechanical pumps with solenoid valves in parallel. The solenoid valve and the pump are started and stopped simultaneously in electrical control, ensuring that if one of the sliding valve mechanical pumps fails and stops, the other parallel sliding valve mechanical pumps can take over the work, so that the pump chamber will not be filled with vacuum oil, resulting in difficulty in starting the pump next time.

[0016] 3. This application obtains vacuum by setting up an oil booster pump to form a vacuum unit, which can meet the process requirements when the vacuum degree is less than 1 Pa.

[0017] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a vacuum pumping unit in an embodiment of the utility model is shown.

[0020] In the figure, 1-sliding valve mechanical pump group, 2-Roots pump group, 21-small Roots pump, 22-large Roots pump, 3-oil booster pump, 4-first high vacuum baffle valve, 5-second high vacuum baffle valve, 6-third high vacuum baffle valve, 7-rotary vane pump, 8-fourth high vacuum baffle valve, 9-first vacuum pumping pipeline, 10-second vacuum pumping pipeline, 11-third vacuum pumping pipeline, 12-furnace body. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] like Figure 1 As shown, a vacuum pumping unit for a vacuum consumable furnace is connected to a furnace body 12 of the vacuum consumable furnace. The vacuum pumping unit includes a first vacuum pumping pipeline 9, and a slide valve mechanical pump group 1 and a Roots pump group 2 arranged on the first vacuum pumping pipeline 9. One end of the first vacuum pumping pipeline 9 is connected to the furnace body 12, and the other end is emptied. The slide valve mechanical pump group 1 is arranged on the first vacuum pumping pipeline 9 and close to the emptied end, and the Roots pump group 2 is arranged on the first vacuum pumping pipeline 9 and close to the furnace body 12.

[0023] When using a VAR furnace to smelt titanium and titanium alloys, since the extracted gas contains corrosive chlorine and dust impurities, the high vacuum flapper valve is working, and the valve stem thread seal often rubs against the valve stem nut and the valve stem stroke is long, which is easily contaminated by chlorine and dust impurities, affecting the sealing performance. The vacuum pumping unit in the prior art usually sets a high vacuum flapper valve between the sliding valve mechanical pump group 1 and the Roots pump group 2, but the sealing structure of the high vacuum flapper valve screw is easily contaminated, resulting in a decrease in sealing, which affects the ultimate vacuum degree of the sliding valve mechanical pump. The sliding valve mechanical pump group 1 of the present application is directly connected to the Roots pump group 2 through the first vacuum pumping pipeline 9, and there is no situation that affects the sealing performance between them, which ensures the ultimate vacuum degree of the sliding valve mechanical pump group 1.

[0024] The sliding valve mechanical pump group 1 includes at least two groups of sliding valve mechanical pumps with solenoid valves connected in parallel to form a sliding valve mechanical pump group. The solenoid valve and the pump are started and stopped simultaneously in electrical control to ensure that if one of the sliding valve mechanical pumps fails and stops, the other parallel sliding valve mechanical pumps can take over the work, so that the pump chamber will not be filled with vacuum oil, resulting in difficulty in starting the pump next time.

[0025] The Roots pump unit 2 plays the role of pressurizing and accelerating the evacuation, and the oil booster pump 3 realizes the evacuation effect with a vacuum degree less than 1 Pa. Both the Roots pump unit 2 and the oil booster pump 3 cannot work from atmospheric pressure, and must be used in combination with the front-stage slide valve mechanical pump. The slide valve mechanical pump's own ultimate vacuum degree plays a vital role in the evacuation efficiency and effect of the vacuum system.

[0026] First, install the electrodes, seal the furnace chamber and the crystallizer to form a closed space, which is now at atmospheric pressure. Start at least two front-stage slide valve mechanical pumps to evacuate, and start the first high vacuum baffle valve 4. As the evacuation proceeds, the closed space gradually changes from atmospheric pressure (101325pa) to a vacuum state.

[0027] At this time, the second high vacuum baffle valve 5 and the third high vacuum baffle valve 6 are both closed, and the first vacuum pumping pipeline 9 remains unobstructed.

[0028] The Roots pump group 2 includes a small Roots pump 21 and a large Roots pump 22 . The small Roots pump 21 is arranged on the first vacuum pipeline 9 and close to the slide valve mechanical pump group 1 . The large Roots pump 22 is arranged on the first vacuum pipeline 9 and close to the furnace body 12 .

[0029] When the vacuum is pumped to 2000Pa, the small Roots pump 21 is started to accelerate the vacuuming. When the vacuum is pumped to 600Pa, the large Roots pump 22 is started to accelerate the vacuuming. Generally, the vacuum is pumped to about 1Pa. The premise of the above normal vacuuming is that the ultimate vacuum degree of at least two sliding valve mechanical pumps in the front stage must be guaranteed to be below 10Pa, otherwise it will affect the vacuuming efficiency and effect. The vacuum pumping unit also includes a second vacuum pumping pipeline 10, and an oil booster pump 3 arranged on the second vacuum pumping pipeline 10. The two ends of the second vacuum pumping pipeline 10 are respectively arranged on both sides of the large Roots pump 22 and connected to the first vacuum pumping pipeline 9. The oil booster pump 3 is connected in parallel with the large Roots pump 22.

[0030] The vacuum pumping unit further includes a first high vacuum baffle valve 4 arranged on the first vacuum pumping pipeline 9 . The first high vacuum baffle valve 4 is arranged between the Roots pumping unit 2 and the furnace body 12 and is close to the Roots pumping unit 2 .

[0031] The vacuum pumping unit also includes a second high vacuum baffle valve 5 and a third high vacuum baffle valve 6 arranged on the second vacuum pumping pipeline 10, the second high vacuum baffle valve 5 is arranged on one side of the oil booster pump 3 and close to the Roots pump group 2, and the third high vacuum baffle valve 6 is arranged on the other side of the oil booster pump 3 and close to the oil booster pump 3.

[0032] The vacuum pumping unit also includes a third vacuum pumping pipeline 11 and a rotary vane pump 7 arranged on the third vacuum pumping pipeline 11. One end of the third vacuum pumping pipeline 11 is arranged between the oil booster pump 3 and the second high vacuum baffle valve 5 and is connected to the second vacuum pumping pipeline 10, and the other end is emptied.

[0033] If the production process requires a vacuum degree of less than 1 Pa, the oil booster pump 3 can be started to perform high vacuum evacuation, which can be evacuated to a high vacuum range of 0.1-0.01 Pa. At this time, the first high vacuum baffle valve 4 is closed, and the second high vacuum baffle valve 5 and the third high vacuum baffle valve 6 are opened to keep the second pipeline unobstructed. At this time, the oil booster pump 3, the small Roots pump 21 and the slide valve mechanical pump work simultaneously.

[0034] The vacuum pumping unit further includes a fourth high vacuum baffle valve 8 arranged on the third vacuum pumping pipeline 11 , and the fourth high vacuum baffle valve 8 is arranged between the end of the third vacuum pumping pipeline 11 communicating with the second vacuum pumping pipeline 10 and the rotary vane pump 7 .

[0035] When the vacuuming is completed, the temperature inside the oil booster pump 3 rises, and the rotary vane pump 7 needs to cool down the oil booster pump 3. At this time, the first high vacuum baffle valve 4, the third high vacuum baffle valve 6 and the second high vacuum baffle valve 5 are closed to keep the second vacuuming pipeline 10 and the third vacuuming pipeline 11 connecting the oil booster pump 3 and the rotary vane pump 7 connected.

[0036] The first high vacuum flapper valve 4, the second high vacuum flapper valve 5, the third high vacuum flapper valve 6, and the fourth high vacuum flapper valve 8 are mainly used to switch the pipeline function. The valve body must ensure the stability of the sealing performance and service life of the valve stem seal during operation, minimize vacuum leakage, shorten the vacuum extraction time, improve production efficiency, and achieve the best vacuum degree to ensure the stability of the production process. The GDQ series pneumatic high vacuum flapper valve (also known as an angle valve) is usually used. It uses compressed air as the power, changes the direction of the air path through the electromagnetic reversing valve, pushes the cylinder piston up and down, drives the valve stem up and down, and opens or closes the valve plate, thereby achieving the purpose of connecting or cutting off the airflow in the vacuum system.

[0037] The slide valve mechanical pump is provided with a solenoid valve inside. The solenoid valve and the pump are started and stopped at the same time in electrical control, so that at least one of the two parallel slide valve mechanical pumps can be stopped, and the pump cavity will not be filled with vacuum oil, which will make it difficult to start the pump next time. There is a vacuum oil film seal between the slide valve in the pump cavity and the inner wall of the pump cavity, which can achieve the sealing of the pump cavity. In addition, the pump cavity and the exhaust pipe are sealed with a valve sheet, so there is no need to worry about leakage between the pump cavity of the slide valve mechanical pump and the atmosphere.

[0038] The first vacuum pipeline 9 between the slide valve mechanical pump group 1 and the Roots pump group 2 includes a bellows pipe. The purpose of providing the bellows pipe is to prevent resonance between the slide valve mechanical pump group 1, the Roots pump group 2 and the direct connection pipeline of the first vacuum pipeline 9.

[0039] Ensure that the slide valve mechanical pump group 1 and the Roots pump group 2 are connected to the first vacuum pipeline 9 through the pipeline flange. The pipeline flange has only a fixed sealing ring to ensure that there is no dynamic seal between the slide valve mechanical pump group 1 and the Roots pump group 2 to affect the ultimate vacuum degree of the slide valve mechanical pump group 1.

[0040] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vacuum pumping unit for a vacuum consumable furnace, connected to a furnace body (12) of the vacuum consumable furnace, characterized in that: The vacuum pumping unit comprises a first vacuum pumping pipeline (9), and a slide valve mechanical pump group (1) and a Roots pump group (2) arranged on the first vacuum pumping pipeline (9); one end of the first vacuum pumping pipeline (9) is connected to a furnace body (12), and the other end is evacuated; the slide valve mechanical pump group (1) is arranged on the first vacuum pumping pipeline (9) and close to the evacuated end; the Roots pump group (2) is arranged on the first vacuum pumping pipeline (9) and close to the furnace body (12); the slide valve mechanical pump group (1) comprises at least two groups of slide valve mechanical pumps connected in parallel.

2. The vacuum pumping unit for a vacuum consumable furnace according to claim 1, characterized in that: The Roots pump group (2) comprises a small Roots pump (21) and a large Roots pump (22); the small Roots pump (21) is arranged on the first vacuum pumping pipeline (9) and is close to the slide valve mechanical pump group (1); and the large Roots pump (22) is arranged on the first vacuum pumping pipeline (9) and is close to the furnace body (12).

3. The vacuum pumping unit for a vacuum consumable furnace according to claim 2, characterized in that: The vacuum pumping unit further comprises a second vacuum pumping pipeline (10) and an oil booster pump (3) arranged on the second vacuum pumping pipeline (10); two ends of the second vacuum pumping pipeline (10) are respectively arranged on both sides of the large Roots pump (22) and are connected to the first vacuum pumping pipeline (9); the oil booster pump (3) is connected in parallel with the large Roots pump (22).

4. The vacuum pumping unit for a vacuum consumable furnace according to claim 1, characterized in that: The vacuum pumping unit further comprises a first high vacuum baffle valve (4) arranged on a first vacuum pumping pipeline (9); the first high vacuum baffle valve (4) is arranged between the Roots pumping unit (2) and the furnace body (12), and is close to the Roots pumping unit (2).

5. The vacuum pumping unit for a vacuum consumable furnace according to claim 3 is characterized in that: The vacuum pumping unit further comprises a second high vacuum baffle valve (5) and a third high vacuum baffle valve (6) arranged on the second vacuum pumping pipeline (10), wherein the second high vacuum baffle valve (5) is arranged on one side of the oil booster pump (3) and close to the Roots pump unit (2), and the third high vacuum baffle valve (6) is arranged on the other side of the oil booster pump (3) and close to the oil booster pump (3).

6. The vacuum pumping unit for a vacuum consumable furnace according to claim 5, characterized in that: The vacuum pumping unit further comprises a third vacuum pumping pipeline (11) and a rotary vane pump (7) arranged on the third vacuum pumping pipeline (11); one end of the third vacuum pumping pipeline (11) is arranged between the oil booster pump (3) and the second high vacuum baffle valve (5) and is connected to the second vacuum pumping pipeline (10); and the other end is emptied.

7. The vacuum pumping unit for a vacuum consumable furnace according to claim 6, characterized in that: The vacuum pumping unit further comprises a fourth high vacuum baffle valve (8) arranged on the third vacuum pumping pipeline (11), wherein the fourth high vacuum baffle valve (8) is arranged between the end of the third vacuum pumping pipeline (11) connected to the second vacuum pumping pipeline (10) and the rotary vane pump (7).

8. The vacuum pumping unit for a consumable vacuum furnace according to claim 1, characterized in that: A solenoid valve is arranged inside the slide valve mechanical pump.

9. The vacuum pumping unit for a vacuum consumable furnace according to claim 1, characterized in that: The first vacuum pipeline (9) between the slide valve mechanical pump unit (1) and the Roots pump unit (2) comprises a bellows pipeline.

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