Vacuum pump system

Abstract

The utility model discloses a vacuum pump system which comprises a first steam pump, a second steam pump, a third steam pump and a fourth steam pump. A second steam pump; a first condenser and a second condenser; a third steam pump and a fourth steam pump; an exhaust pipe is connected out of the top of a second condenser C2, two water ring pumps connected in parallel are connected, outlets of the water ring pumps are converged and connected to an exhaust pipe, then an exhaust gas discharge pipe is connected, and a corresponding control valve is arranged on a pipeline, so that the performance of the vacuum pump is remarkably improved, and the continuous and stable capacity of ultimate vacuum of 0-0.67 mbar can be achieved. The average value of the [H] content in the molten steel is reduced by 10%, the dehydrogenation rate is improved by 10%, and meanwhile the operation cost is reduced. Meanwhile, the pneumatic valve and the manual valve are arranged on the air suction pipelines of the two water ring pumps respectively, manual control and automatic control can be achieved at the same time, and maintenance is convenient.

Description

Technical Field

[0001] The utility model relates to the field of a molten steel refining vacuum system (RH) outside a steel metallurgical furnace, and in particular to a vacuum pump system. Background Art

[0002] Hydrogen exists in metals primarily in the form of atoms, molecules, metal hydrides, and transient hydrogen ions. Hydrogen enters the metal and interacts with it, reducing its mechanical properties, such as toughness and plasticity, leading to brittle fracture or cracking, and hydrogen damage. The main hazards in steel include hydrogen embrittlement, hydrogen blistering, decarburization that reduces surface hardness and fatigue strength, and hydrogen corrosion. To achieve this, the hydrogen content in steel must be minimized. Steam-based RH treatment devices, VD-type ladle refining furnaces, or mechanical pumping systems are commonly used.

[0003] RH processing equipment is generally a double-chamber translational integral vacuum chamber structure, mainly composed of a vacuum system, alloy and slag addition system, top gun heating system, hydraulic lifting system, water treatment system and automatic control system.

[0004] With the improvement of the control level of hydrogen content parameters in molten steel during the subsequent continuous casting process, the current vacuum pump system has problems such as large vacuum fluctuation, insufficient ultimate vacuum capacity, insufficient vacuum stabilization time and high operating costs. Utility Model Content

[0005] In view of this, in order to overcome at least one aspect of the above problems, an embodiment of the present invention provides a vacuum pump system, comprising:

[0006] a first steam pump, wherein an air inlet of the first steam pump receives steelmaking waste gas;

[0007] a second steam pump, wherein an air inlet of the second steam pump is connected to an air outlet of the first steam pump;

[0008] a first condenser, wherein the air inlet of the first condenser is connected to the air outlet of the second steam pump,

[0009] Second condenser;

[0010] a third steam pump and a fourth steam pump;

[0011] The first air outlet of the first condenser is connected to the air inlet of the third steam pump, the second air outlet of the first condenser is connected to the air inlet of the fourth steam pump, the first air inlet of the second condenser is connected to the air outlet of the third steam pump, and the second air inlet of the second condenser is connected to the air outlet of the fourth steam pump;

[0012] a first water ring pump, wherein an air inlet of the first water ring pump is connected to a top air outlet of the second condenser through a first branch, and a first manual valve and a first pneumatic valve are provided on the first branch;

[0013] A second water ring pump, wherein the air inlet of the second water ring pump is connected to the top air outlet of the second condenser through a second branch, and a second manual valve and a second pneumatic valve are provided on the second branch.

[0014] In some embodiments, the air outlet of the first water ring pump is connected to the external atmosphere through a first exhaust branch;

[0015] The air outlet of the second water ring pump is communicated with the external atmosphere through a second exhaust branch.

[0016] In some embodiments, the first exhaust branch is provided with a first manual butterfly valve;

[0017] The second exhaust branch is provided with a second manual butterfly valve.

[0018] In some embodiments, the vacuum pump system further comprises:

[0019] Sealing the pool;

[0020] The bottom exhaust port of the first condenser and the bottom exhaust port of the second condenser are connected to the sealed water pool.

[0021] In some embodiments, the vacuum pump system further comprises:

[0022] The third condenser;

[0023] a fifth steam pump and a sixth steam pump;

[0024] The first air outlet of the second condenser is connected to the air inlet of the fifth steam pump, the second air outlet of the second condenser is connected to the air inlet of the sixth steam pump, the first air inlet of the third condenser is connected to the air outlet of the fifth steam pump, and the second air inlet of the third condenser is connected to the air outlet of the sixth steam pump;

[0025] The air outlet of the third condenser is communicated with the external atmosphere.

[0026] In some embodiments, the bottom exhaust port of the third condenser is connected to the sealing water tank.

[0027] In some embodiments, one of the first water ring pump and the second water ring pump is a main pump, and the other is a secondary main pump.

[0028] In some embodiments, one of the first water ring pump and the second water ring pump is a main pump;

[0029] The fifth steam pump and the sixth steam pump are auxiliary pumps.

[0030] In some embodiments, one of the first water ring pump and the second water ring pump is a main pump, and the other is a secondary main pump;

[0031] The fifth steam pump and the sixth steam pump are auxiliary pumps.

[0032] In some embodiments, one of the fifth steam pump and the sixth steam pump is a main pump, and the other is a secondary pump.

[0033] The utility model has the following beneficial technical effects: The proposed solution connects an exhaust pipe from the top of the second condenser C2 to two parallel water ring pumps. The water ring pump outlets converge and connect to an exhaust pipe, which is then connected to the exhaust gas discharge pipe. Appropriate control valves are installed on the pipe, significantly improving vacuum pump performance, achieving a continuous and stable ultimate vacuum of 0 to 0.67 mbar. This reduces the average [H] content in molten steel by 10%, increases the dehydrogenation rate by 10%, and reduces operating costs. Furthermore, pneumatic and manual valves are installed on the suction pipes of the two water ring pumps, respectively, enabling both manual and automatic control and facilitating maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 A structural block diagram of a vacuum pump system provided in an embodiment of the present utility model;

[0036] Figure 2 Parameter diagram of the water ring pump provided in the embodiment of the present utility model;

[0037] Figure 3 The working process of deep dehydrogenation performed by the vacuum pump system provided in the embodiment of the present utility model;

[0038] Figure 4 The vacuum pump system of the embodiment of the present utility model provides four working modes;

[0039] Figure 5 These are the ultimate vacuum test values ​​of the steam pump and water ring pump under several loads provided in the embodiments of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0041] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two non-identical entities or non-identical parameters with the same name. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. Subsequent embodiments will not explain this one by one.

[0042] According to one aspect of the present invention, an embodiment of the present invention provides a vacuum pump system, such as Figure 1 As shown, it may include:

[0043] a first steam pump B1, wherein the gas inlet of the first steam pump B1 receives steelmaking waste gas;

[0044] a second steam pump B2, wherein the air inlet of the second steam pump B2 is connected to the air outlet of the first steam pump B1;

[0045] The first condenser C1, the air inlet of the first condenser C1 is connected to the air outlet of the second steam pump B2,

[0046] Second condenser C2;

[0047] The third steam pump is S3a and the fourth steam pump is S3b;

[0048] The first air outlet of the first condenser C1 is connected to the air inlet of the third steam pump S3a, the second air outlet of the first condenser C1 is connected to the air inlet of the fourth steam pump S3b, the first air inlet of the second condenser C2 is connected to the air outlet of the third steam pump S3a, and the second air inlet of the second condenser C2 is connected to the air outlet of the fourth steam pump S3b;

[0049] a first water ring pump W4a, wherein the air inlet of the first water ring pump W4a is connected to the top air outlet of the second condenser C2 through a first branch, and a first manual valve and a first pneumatic valve are provided on the first branch;

[0050] The second water ring pump W4b has an air inlet connected to the top air outlet of the second condenser C2 through a second branch, and a second manual valve and a second pneumatic valve are provided on the second branch.

[0051] The proposed solution connects an exhaust pipe from the top of the second condenser C2 to two parallel water ring pumps. The pump outlets converge into a single exhaust pipe, which then connects to the exhaust gas discharge pipe. Appropriate control valves are installed on the pipes. This significantly improves vacuum pump performance, achieving a continuous and stable ultimate vacuum of 0 to 0.67 mbar. This reduces the average [H] content in molten steel by 10%, increases the dehydrogenation rate by 10%, and reduces operating costs. Furthermore, pneumatic and manual valves are installed on the suction pipes of the two water ring pumps, respectively, enabling both manual and automatic control and facilitating maintenance.

[0052] A water ring pump achieves suction, compression, and exhaust through changes in the pump chamber volume, making it a variable displacement vacuum pump. Its operating principle is as follows: an appropriate amount of water is contained in the pump body as the working fluid. When the impeller rotates clockwise as shown in the figure, water is thrown in all directions by the impeller. Due to centrifugal force, the water forms a closed circular ring of approximately constant thickness, determined by the shape of the pump chamber. The lower inner surface of the water ring is tangent to the impeller hub, and the upper inner surface of the water ring just contacts the blade tips (in fact, the blades are inserted into the water ring to a certain depth). At this point, a crescent-shaped space is formed between the impeller hub and the water ring, which is divided by the impeller into a number of small chambers equal to the number of blades. If the lower part of the impeller at 0° is taken as the starting point, the volume of the small cavity will increase from small to large during the first 180° rotation of the impeller, and will be connected to the air intake port on the end face. At this time, the gas is sucked in, and when the air intake ends, the small cavity will be isolated from the air intake port. When the impeller continues to rotate, the small cavity will decrease from large to small, causing the gas to be compressed. When the small cavity is connected to the exhaust port, the gas will be discharged out of the pump.

[0053] Features of water ring pumps: (1) Simple structure, low manufacturing precision requirements, and easy processing. (2) Compact structure, high pump speed, generally can be directly connected to the motor without the need for a reduction device. Therefore, with a small structural size, a large exhaust volume can be obtained, and the floor space is also small. (3) The compressed gas is basically isothermal, that is, the temperature change of the compressed gas process is very small. (4) Since there is no metal friction surface in the pump chamber, there is no need to lubricate the pump, and the wear is very small. The sealing between the rotating parts and the fixed parts can be directly completed by the water seal.

[0054] like Figure 2 As shown, the water ring vacuum pump unit can be selected as follows:

[0055] According to the operating characteristic curves of steam jet pumps S4a and S4b, the pumping rate of a single water ring pump should be greater than 1800kg / h under the working pressure of 330mbar:

[0056] Therefore, two SKA (2BE1) 403 water ring vacuum pumps are selected, and their performance parameters are as follows:

[0057] Pump inlet temperature ≤50℃

[0058] Ultimate vacuum ≤100mbar

[0059] Working fluid pressure ≤0.35MPa

[0060] Working fluid consumption ≤ 25m 3 / h

[0061] Speed ​​372r / min

[0062] Matching motor Y315M-4-132kw 380V 1487rmp

[0063] Dimensions (length, width, height) 2170×1370×1265

[0064] A particularly important parameter is the ultimate vacuum degree ≤ 100 mbar.

[0065] In some embodiments, the air outlet of the first water ring pump W4a is connected to the external atmosphere through a first exhaust branch;

[0066] The air outlet of the second water ring pump W4b is connected to the external atmosphere through a second exhaust branch.

[0067] In some embodiments, the first exhaust branch is provided with a first manual butterfly valve;

[0068] The second exhaust branch is provided with a second manual butterfly valve.

[0069] In some embodiments, the vacuum pump system further comprises:

[0070] Sealing the pool;

[0071] The bottom exhaust port of the first condenser C1 and the bottom exhaust port of the second condenser C2 are connected to the sealed water pool.

[0072] In some embodiments, the vacuum pump system further comprises:

[0073] The third condenser;

[0074] a fifth steam pump S4a and a sixth steam pump S4b;

[0075] The first air outlet of the second condenser C2 is connected to the air inlet of the fifth steam pump S4a, the second air outlet of the second condenser C2 is connected to the air inlet of the sixth steam pump S4b, the first air inlet of the third condenser is connected to the air outlet of the fifth steam pump S4a, and the second air inlet of the third condenser is connected to the air outlet of the sixth steam pump S4b;

[0076] The air outlet of the third condenser is communicated with the external atmosphere.

[0077] In some embodiments, the bottom exhaust port of the third condenser is connected to the sealing water tank.

[0078] In some embodiments, one of the first water ring pump W4a and the second water ring pump W4b is a main pump, and the other is a secondary main pump.

[0079] In some embodiments, one of the first water ring pump W4a and the second water ring pump W4b is a main pump;

[0080] The fifth steam pump S4a and the sixth steam pump S4b are auxiliary pumps.

[0081] In some embodiments, one of the first water ring pump W4a and the second water ring pump W4b is a main pump, and the other is a secondary main pump;

[0082] The fifth steam pump S4a and the sixth steam pump S4b are auxiliary pumps.

[0083] In some embodiments, one of the fifth steam pump S4a and the sixth steam pump S4b is a main pump, and the other is a secondary pump.

[0084] Specifically, an exhaust pipe is connected from the top of the C2 condenser to two parallel water ring pumps. The vacuum pump system has two application modes: one is the B1+B2+3a / 3b+4a / 4b normal vacuum mode, which meets the requirements of ≤3mbar during the entire molten steel treatment process; the other is the B1+B2+3a / 3b+4c / 4d extreme vacuum mode, which meets the requirements of ≤1mbar during the entire molten steel treatment process, with an ultimate vacuum of 0-0.67mbar without molten steel. The two modes can also be switched.

[0085] 1. Steam pump working mode

[0086] Steam pump working principle: adopts B1+B2+3a / 3b+4a / 4b mode, and its pump system equipment mainly consists of B1, B2, 3a3b, 4a4b steam jet pumps and C1, C2, C3 condensers and valves at all levels;

[0087] 2. Steam pump + water ring pump working mode

[0088] On the basis of the original steam pump equipment, the parallel water ring pump is used as a replacement pump for the final stage pump (4a, 4b), while the final stage steam pump is retained as a backup pump, which operates in B1+B2+3a / 3b+4c / 4d extreme vacuum mode.

[0089] During production, after the RH treatment mode starts, the 4c ​​and 4d water ring pumps are started directly. When the vacuum degree reaches 300mbar, the steam pump working mode is entered, and the subsequent working conditions are the same as those of the steam pump. For example, Figure 3 The deep dehydrogenation water ring pump shown is in normal working mode.

[0090] In some embodiments, as Figure 4 As shown, the 4-stage vacuum pump consists of 2 water ring pumps and 2 steam jet pumps. Any one of the 4 pumps can be started individually, or 2-3 pumps can be started at the same time. In principle, in order to save energy and reduce consumption, water ring pumps (W4c / W4d) should be used as much as possible:

[0091] (1) Main pump selection (4A): Select any one of the water ring pumps (W4c / W4d), and it must be selected and always in working condition. When both water ring pumps cannot be used (such as failure or maintenance), a steam pump can also be selected.

[0092] (2) Secondary main pump selection (4A+): You can select any water ring pump other than the main pump, or you can not select it. In the early stage of vacuum treatment, when the exhaust gas flow is large, it works in parallel with the main pump to improve the extraction capacity. In the later stage of vacuum treatment, when the exhaust gas volume is small, it is shut down to save energy. It does not participate in pre-extraction. When the system starts, the pump will be stopped after the vacuum reaches the set pressure (usually set to 3mbar).

[0093] (3) Auxiliary pump selection (4B): You can select any steam pump other than the main pump and auxiliary pump, or you can choose none. When the exhaust gas flow rate is high in the initial stage of vacuum treatment, the auxiliary pump works in parallel with the main pump to improve the extraction capacity. When the exhaust gas volume is low in the later stage of vacuum treatment, the auxiliary pump is shut down to save energy. The auxiliary pump does not participate in pre-extraction and stops when the vacuum reaches 300 mbar when the system starts.

[0094] like Figure 5 The ultimate vacuum test values ​​of steam pump and water ring pump under several loads are shown. From the comparison of test results, the ultimate vacuum capacity of steam pump and water ring pump combination is better than that of steam pump system. The energy consumption is significantly reduced: steam consumption ≤ 13t / h, pure steam pump working is 20.13t / h; turbid water consumption ≤ 900m 3 / h, saving 100 m 3 / h. The system is highly stable. Because water ring pumps are less sensitive to medium temperature, they are less affected by vacuum fluctuations and operate more stably than steam pumps. Using the B1+B2+3a+4c4d mode, the required vacuum level can be reached in 3 minutes. The leakage limit load when processing molten steel is increased from 600kg / h for steam pumps to 750kg / h, resulting in a 20% improvement in pumping performance compared to steam pumps. This improves the pumping capacity and stability of the pump system and reduces the RH system failure rate by over 80%.

[0095] The proposed solution connects an exhaust pipe from the top of the second condenser C2 to two parallel water ring pumps. The pump outlets converge into a single exhaust pipe, which then connects to the exhaust gas discharge pipe. Appropriate control valves are installed on the pipes. This significantly improves vacuum pump performance, achieving a continuous and stable ultimate vacuum of 0 to 0.67 mbar. This reduces the average [H] content in molten steel by 10%, increases the dehydrogenation rate by 10%, and reduces operating costs. Furthermore, pneumatic and manual valves are installed on the suction pipes of the two water ring pumps, respectively, enabling both manual and automatic control and facilitating maintenance.

[0096] The above are exemplary embodiments disclosed by the present invention, but it should be noted that various changes and modifications can be made without departing from the scope of the disclosure of the embodiments of the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention can be described or required in individual form, they can also be understood as multiple unless expressly limited to the singular.

[0097] It should be understood that, as used herein, the singular forms "a" and "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" is intended to include any and all possible combinations of one or more of the associated listed items.

[0098] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0099] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the disclosure of the present invention is limited to these examples. Based on the principles of the present invention, the technical features of the above embodiments or different embodiments may be combined, and there are many other variations of the various aspects of the above embodiments, which are not provided in detail for the sake of clarity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vacuum pump system, characterized in that: include: a first steam pump, wherein an air inlet of the first steam pump receives steelmaking waste gas; a second steam pump, wherein an air inlet of the second steam pump is connected to an air outlet of the first steam pump; a first condenser, wherein the air inlet of the first condenser is connected to the air outlet of the second steam pump, Second condenser; a third steam pump and a fourth steam pump; The first air outlet of the first condenser is connected to the air inlet of the third steam pump, the second air outlet of the first condenser is connected to the air inlet of the fourth steam pump, the first air inlet of the second condenser is connected to the air outlet of the third steam pump, and the second air inlet of the second condenser is connected to the air outlet of the fourth steam pump; a first water ring pump, wherein an air inlet of the first water ring pump is connected to a top air outlet of the second condenser through a first branch, and a first manual valve and a first pneumatic valve are provided on the first branch; A second water ring pump, wherein the air inlet of the second water ring pump is connected to the top air outlet of the second condenser through a second branch, and a second manual valve and a second pneumatic valve are provided on the second branch.

2. The vacuum pump system according to claim 1, wherein: The air outlet of the first water ring pump is connected to the external atmosphere through the first exhaust branch; The air outlet of the second water ring pump is communicated with the external atmosphere through a second exhaust branch.

3. The vacuum pump system according to claim 2, wherein: The first exhaust branch is provided with a first manual butterfly valve; The second exhaust branch is provided with a second manual butterfly valve.

4. The vacuum pump system according to claim 1, wherein: Also includes: Sealing the pool; The bottom exhaust port of the first condenser and the bottom exhaust port of the second condenser are connected to the sealed water pool.

5. The vacuum pump system according to claim 4, wherein: Also includes: The third condenser; a fifth steam pump and a sixth steam pump; The first air outlet of the second condenser is connected to the air inlet of the fifth steam pump, the second air outlet of the second condenser is connected to the air inlet of the sixth steam pump, the first air inlet of the third condenser is connected to the air outlet of the fifth steam pump, and the second air inlet of the third condenser is connected to the air outlet of the sixth steam pump; The air outlet of the third condenser is communicated with the external atmosphere.

6. The vacuum pump system according to claim 5, wherein: The bottom exhaust port of the third condenser is connected to the sealing water tank.

7. The vacuum pump system according to claim 5, wherein: One of the first water ring pump and the second water ring pump is a main pump, and the other is a secondary main pump.

8. The vacuum pump system according to claim 5, wherein: One of the first water ring pump and the second water ring pump is a main pump; The fifth steam pump and the sixth steam pump are auxiliary pumps.

9. The vacuum pump system according to claim 5, wherein: One of the first water ring pump and the second water ring pump is a main pump, and the other is a secondary main pump; The fifth steam pump and the sixth steam pump are auxiliary pumps.

10. The vacuum pump system according to claim 5, wherein: One of the fifth steam pump and the sixth steam pump is a main pump, and the other is a secondary pump.

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