阅读说明：本技术 一种电子束冷床炉自动抽真空装置及启动控制方法 (Automatic vacuumizing device of electron beam cold hearth furnace and starting control method ) 是由 巫乔顺 皮坤 刘洪具 沈志彦 杨开 罗磊 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种电子束冷床炉自动抽真空装置及启动控制方法。所述装置的电磁阀Ⅰ与加料仓抽真空口连通且并联真空度检测装置Ⅰ,增压泵两端与电磁阀Ⅰ、电磁阀Ⅱ和电磁阀Ⅳ连通,电磁阀Ⅱ、罗茨泵Ⅰ、电磁阀Ⅲ、机械泵Ⅰ依次连通,电磁阀Ⅱ与罗茨泵Ⅰ间并联真空度检测装置Ⅱ,电磁阀Ⅲ与机械泵Ⅰ间并联真空度检测装置Ⅲ；电磁阀Ⅳ、罗茨泵Ⅱ、电磁阀Ⅴ、机械泵Ⅱ依次连通,电磁阀Ⅳ与罗茨泵Ⅱ间并联真空度检测装置Ⅳ,电磁阀Ⅴ与机械泵Ⅱ间并联真空度检测装置Ⅴ；机械泵Ⅰ及机械泵Ⅱ与排空装置连通。所述启动控制方法包括增压泵、罗茨泵Ⅱ、机械泵Ⅱ、罗茨泵Ⅰ及机械泵Ⅰ控制步骤。本发明具有结构简单、抽真空效率高、真空度控制准确可靠的特点。(The invention discloses an automatic vacuumizing device of an electron beam cold hearth furnace and a starting control method. The device is characterized in that a solenoid valve I of the device is communicated with a vacuum pumping port of a feeding bin and is connected with a vacuum degree detection device I in parallel, two ends of a booster pump are communicated with the solenoid valve I, a solenoid valve II and a solenoid valve IV, the solenoid valve II, a roots pump I, a solenoid valve III and a mechanical pump I are sequentially communicated, the vacuum degree detection device II is connected between the solenoid valve II and the roots pump I in parallel, and the vacuum degree detection device III is connected between the solenoid valve III and the mechanical pump I in parallel; the electromagnetic valve IV, the roots pump II, the electromagnetic valve V and the mechanical pump II are sequentially communicated, the vacuum degree detection device IV is connected between the electromagnetic valve IV and the roots pump II in parallel, and the vacuum degree detection device V is connected between the electromagnetic valve V and the mechanical pump II in parallel; the mechanical pump I and the mechanical pump II are communicated with an emptying device. The starting control method comprises the control steps of a booster pump, a roots pump II, a mechanical pump II, a roots pump I and a mechanical pump I. The invention has the characteristics of simple structure, high vacuum pumping efficiency and accurate and reliable vacuum degree control.)

1. The automatic vacuum-pumping device of the electron beam cold hearth furnace is characterized by comprising a vacuum degree detection device I (2), an electromagnetic valve I (3), a booster pump (4), an electromagnetic valve II (6), a vacuum degree detection device II (7), a Roots pump I (8), an electromagnetic valve III (9), a vacuum degree detection device III (10), a mechanical pump I (11), an electromagnetic valve IV (14), a vacuum degree detection device IV (15), a Roots pump II (16), an electromagnetic valve V (17), a vacuum degree detection device V (18), a mechanical pump II (19), an emptying device (20) and a control system (21), wherein the electromagnetic valve I (3) is communicated with a vacuum-pumping port of a feeding bin (1) of the electron beam cold hearth furnace and is connected with the vacuum degree detection device I (2) in parallel, the other end of the electromagnetic valve I (3) is communicated with the booster pump (4), and the other end of the booster pump (4) is respectively communicated with the electromagnetic valve II (6), The electromagnetic valve IV (14) is communicated, the electromagnetic valve II (6), the roots pump I (8), the electromagnetic valve III (9) and the mechanical pump I (11) are sequentially communicated, a vacuum degree detection device II (7) is connected between the electromagnetic valve II (6) and the roots pump I (8) in parallel, and a vacuum degree detection device III (10) is connected between the electromagnetic valve III (9) and the mechanical pump I (11) in parallel; the electromagnetic valve IV (14), the roots pump II (16), the electromagnetic valve V (17) and the mechanical pump II (19) are sequentially communicated, a vacuum degree detection device IV (15) is connected in parallel between the electromagnetic valve IV (14) and the roots pump II (16), and a vacuum degree detection device V (18) is connected in parallel between the electromagnetic valve V (17) and the mechanical pump II (19); the vacuum degree detection device comprises a mechanical pump I (11), a mechanical pump II (19), a vacuum degree detection device I (2), a vacuum degree detection device II (7), a vacuum degree detection device III (10), a vacuum degree detection device IV (15) and a vacuum degree detection device V (18), wherein outlet ends of the mechanical pump I (11) and the mechanical pump II (19) are communicated with an emptying device (20), output ends of the vacuum degree detection device I (2), the vacuum degree detection device II (7), the vacuum degree detection device III (10), the vacuum degree detection device IV (15) and the vacuum degree detection device V (18) are respectively electrically connected with an input end of a control system (21), and control ends of an electromagnetic valve I (3), a booster pump (4), an electromagnetic valve II (6), a roots pump I (8), an electromagnetic valve III (9), the mechanical pump I (11), an electromagnetic valve IV (14), a roots pump II (16), an electromagnetic valve V (17) and the mechanical pump II (19) are respectively electrically connected with an output end of the control system (21).

2. The automatic vacuum pumping device of the electron beam cold hearth furnace according to claim 1, characterized in that the feeding bin (1) of the electron beam cold hearth furnace is provided with at least two vacuum pumping ports, each vacuum pumping port of the feeding bin (1) is sequentially communicated with a solenoid valve I (3) and a booster pump (4), and outlet ends of the booster pumps (4) connected with the vacuum pumping ports of the feeding bin (1) are communicated with each other and then respectively communicated with a solenoid valve II (6) and a solenoid valve IV (14).

3. The automatic vacuum pumping device of the electron beam cold bed furnace according to claim 2, characterized in that an oil receiver (5) is arranged between the booster pump (4) and the solenoid valve II (6) and the solenoid valve IV (14), the inlet end of the oil receiver (5) is communicated with the booster pump (4), and the outlet end is respectively communicated with the solenoid valve II (6) and the solenoid valve IV (14).

4. The automatic vacuum pumping device of the electron beam cold hearth according to claim 3, wherein the outlet end of the oil receiver (5) is further communicated with the inlet end of a switch valve I (12) and/or a switch valve II (13), the outlet end of the switch valve I (12) is communicated with the inlet end of a solenoid valve III (9), and the outlet end of the switch valve II (13) is communicated with the inlet end of a solenoid valve V (17).

5. The automatic vacuum-pumping device of electron beam cold hearth furnace according to any one of claims 1 to 4, characterized by further comprising a frequency converter (22) and a contactor (23) electrically connected with the control end of the control system (21), wherein the roots pump I (8) and the mechanical pump I (11) are respectively connected with a variable frequency motor (24), the roots pump II (16) and the mechanical pump II (19) are respectively connected with an asynchronous motor (25), the power end of the variable frequency motor (24) is electrically connected with the driving output end of the frequency converter (22), and the power control end of the asynchronous motor (25) is electrically connected with the contactor (23).

6. The automatic vacuum extractor of an electron beam cold hearth according to claim 5, wherein power control terminals of the solenoid valve I (3), the solenoid valve II (6), the solenoid valve III (9), the solenoid valve IV (14) and the solenoid valve V (17) are electrically connected to the contactor (23) respectively, and a valve position signal output terminal of each solenoid valve is electrically connected to an input terminal of the control system (21) respectively.

7. The automatic vacuum pumping device of electron beam cold hearth furnace according to claim 5, characterized in that said booster pump (4), said roots pump I (8), said mechanical pump I (11), said roots pump II (16) and said mechanical pump II (19) are respectively provided with a pump signal feedback unit and electrically connected with the input end of the control system (21).

8. A start-up control method of the electron beam cold hearth furnace automatic vacuum pumping device according to claim 5, 6 or 7, characterized by comprising the steps of booster pump control, Roots pump II control, mechanical pump II control, Roots pump I control and mechanical pump I control, and specifically comprising:

A. and (3) booster pump control: the control system (21) controls the electromagnetic valve I (3) to be opened, then the booster pump (4) is started, and when the detection value of the vacuum degree detection device I (2) is read to reach a set value, a starting ready signal of the roots pump II (16) is output;

B. and a Roots pump II: the control system (21) controls the electromagnetic valve IV (14) to be opened and starts the roots pump II (16), and outputs a starting ready signal of the mechanical pump II (19) when the detection value of the vacuum degree detection device IV (15) is read to reach a set value;

C. and (4) controlling a mechanical pump II: the control system (21) controls the electromagnetic valve V (17) to be opened and starts the mechanical pump II (19), and outputs a ready signal for starting the frequency converter (22) when the detection value of the vacuum degree detection device V (18) is read to reach a set value;

D. and (3) controlling a Roots pump I: the control system (21) controls the electromagnetic valve II (6) to be opened and controls the frequency converter (22) to start the roots pump I (8), reads the detection value of the vacuum degree detection device II (7), and then controls the frequency output to the roots pump I (8) by the frequency converter (22) to change along with the detection value of the vacuum degree;

E. and (3) controlling a mechanical pump I: the control system (21) controls the electromagnetic valve III (9) to be opened and controls the frequency converter (22) to start the mechanical pump I (11), the detection value of the vacuum degree detection device III (10) is read, and the frequency output to the mechanical pump I (11) by the frequency converter (22) is controlled to change along with the detection value of the vacuum degree.

9. The start-up control method of the electron beam cold hearth automatic vacuum pumping device according to claim 8, characterized in that when the roots pump i (8) and/or the roots pump ii (16) is failed or is in standby for being shut down, the control system (21) controls the corresponding on-off valve i (12) and the corresponding on-off valve ii (13) to be opened, then stops the roots pump i (8) and/or the roots pump ii (16), and finally closes the corresponding electromagnetic valve ii (6) and the corresponding electromagnetic valve iv (14).

10. The method of claim 8, wherein the sealing condition of the corresponding pipe is checked if the detected value of the vacuum degree detector is not changed or does not reach the set value after the pump is started.

Technical Field

The invention belongs to the technical field of metallurgical equipment, and particularly relates to an automatic vacuumizing device of an electron beam cold hearth furnace and a starting control method, wherein the automatic vacuumizing device is simple in structure, high in vacuumizing efficiency and accurate and reliable in vacuum degree control.

Background

An electron beam cold hearth furnace (EBCHR) is a vacuum melting device which utilizes the kinetic energy of high-speed moving electrons to be converted into heat energy to be used as a heat source to melt metal to generate cast ingots. Compared with the traditional vacuum consumable arc melting, the EBCHR melting maintains stable vacuum in the smelting furnace through the vacuum pumping device, thereby reducing the influence sensitivity to pressure change and metal gas and even splashes in the melting process, having the advantages of removing high and low density inclusions (HDI and LDI), melting original charge and 100 percent titanium residue and low-quality sponge titanium, directly producing ingots such as circular and square sections and slab ingots, and the like, and occupying quite important position in the production of high-quality titanium and titanium alloy ingots.

The vacuum pumping system of the electron beam cold bed furnace is complex, at present, a roots pump, a mechanical booster pump or an oil booster pump and a mechanical pump are generally adopted to work in parallel, the work coordination among the pumps adopts a manual control mode, the vacuum pumping efficiency is low, the remote centralized control function is not provided, a large amount of manpower is occupied on the spot, meanwhile, the manual operation has hysteresis, and the stability of the vacuum degree cannot be effectively maintained. In addition, the traditional vacuum pumping system adopts a contactor to directly control transmission, so that the rotating speed of a motor of a pump is uncontrollable, and the vacuum degree in an electron beam cooling bed furnace is difficult to be stabilized within a specific set value range. In addition, the traditional electron beam cold bed furnace has extremely poor field environment, and dust and noise seriously affect the health of post operators, so the electron beam cold bed furnace is not suitable for long-term attendance.

Disclosure of Invention

The invention aims to provide an automatic vacuum-pumping device of an electron beam cold hearth furnace, which has the advantages of simple structure, high vacuum-pumping efficiency and accurate and reliable vacuum degree control, and aims to provide a starting control method for the first purpose scheme.

The first object of the present invention is achieved by: comprises a vacuum degree detection device I, an electromagnetic valve I, a booster pump, an electromagnetic valve II, a vacuum degree detection device II, a Roots pump I, an electromagnetic valve III, a vacuum degree detection device III, a mechanical pump I, an electromagnetic valve IV, a vacuum degree detection device IV, a Roots pump II, an electromagnetic valve V, a vacuum degree detection device V, a mechanical pump II, an emptying device and a control system, the electromagnetic valve I is communicated with a vacuum pumping port of a feeding bin of the electron beam cold hearth furnace and is connected with a vacuum degree detection device I in parallel, the other end of the electromagnetic valve I is communicated with a booster pump, the other end of the booster pump is respectively communicated with an electromagnetic valve II and an electromagnetic valve IV, the electromagnetic valve II, the roots pump I, the electromagnetic valve III and the mechanical pump I are sequentially communicated, a vacuum degree detection device II is connected between the electromagnetic valve II and the roots pump I in parallel, and a vacuum degree detection device III is connected between the electromagnetic valve III and the mechanical pump I in parallel; the electromagnetic valve IV, the roots pump II, the electromagnetic valve V and the mechanical pump II are sequentially communicated, a vacuum degree detection device IV is connected between the electromagnetic valve IV and the roots pump II in parallel, and a vacuum degree detection device V is connected between the electromagnetic valve V and the mechanical pump II in parallel; the output ends of the vacuum degree detection device I, the vacuum degree detection device II, the vacuum degree detection device III, the vacuum degree detection device IV and the vacuum degree detection device V are respectively and electrically connected with the input end of the control system, and the control ends of the electromagnetic valve I, the booster pump, the electromagnetic valve II, the roots pump I, the electromagnetic valve III, the mechanical pump I, the electromagnetic valve IV, the roots pump II, the electromagnetic valve V and the mechanical pump II are respectively and electrically connected with the output end of the control system.

The second object of the present invention is achieved by: including booster pump control, II controls of lobe pump, II controls of mechanical pump, I controls of lobe pump, I control step of mechanical pump, specifically include:

A. and (3) booster pump control: the control system controls the electromagnetic valve I to be opened, then the booster pump is started, and when the detection value of the vacuum degree detection device I is read to reach a set value, a starting ready signal of the Roots pump II is output;

B. and a Roots pump II: the control system controls the electromagnetic valve IV to be opened and starts the roots pump II, and outputs a starting ready signal of the mechanical pump II when the detection value of the vacuum degree detection device IV is read to reach a set value;

C. and (4) controlling a mechanical pump II: the control system controls the electromagnetic valve V to be opened and starts the mechanical pump II, and when the detection value of the vacuum degree detection device V is read to reach a set value, a frequency converter starting ready signal is output;

D. and (3) controlling a Roots pump I: the control system controls the electromagnetic valve II to be opened and controls the frequency converter to start the Roots pump I, reads the detection value of the vacuum degree detection device II, and then controls the frequency output by the frequency converter to the Roots pump I to change along with the detection value of the vacuum degree;

E. and (3) controlling a mechanical pump I: the control system controls the electromagnetic valve III to be opened and controls the frequency converter to start the mechanical pump I, reads the detection value of the vacuum degree detection device III, and controls the frequency output by the frequency converter to the mechanical pump I to change along with the detection value of the vacuum degree.

The invention has the beneficial effects that: the vacuum loop is designed into a three-stage and double-channel structure, the roots pump and the mechanical pump are designed into a series operation mechanism, a pressure detection point and a switch valve are arranged in front of each vacuum pump and used for real-time vacuum degree detection and pipeline on-off control, an online vacuum degree and equipment monitoring and variable frequency control technology is introduced, the cooperation of the double channels and the double pumps is automatically adjusted, the adverse effects of human factors are reduced and even avoided, the accuracy and reliability of vacuum degree control in the electron beam cooling bed furnace can be effectively improved, the labor efficiency is improved, and the influence of the field environment on the body health of operators can be reduced. By adding a bypass loop which strides over the roots pump to directly pump vacuum, the roots pump can pump vacuum without working, so that the loss of the roots pump is reduced, and the reliability of the vacuum pumping device is improved; and the temporary switching can be carried out when the Roots pump is damaged so as to maintain the smelting process. Therefore, the invention has the characteristics of simple structure, high vacuum pumping efficiency and accurate and reliable vacuum degree control.

Drawings

FIG. 1 is a schematic view of the connection of the automatic vacuum-pumping device (partially controlled) according to the present invention;

FIG. 2 is a schematic view of the connection of the control part of the automatic vacuum pumping device of the present invention;

FIG. 3 is a schematic diagram of the electrical principle of the control system of the present invention;

in the figure: 1-a feeding bin, 2-a vacuum degree detection device I, 3-an electromagnetic valve I, 4-a booster pump, 5-an oil receiver, 6-an electromagnetic valve II, 7-a vacuum degree detection device II, 8-a roots pump I, 9-an electromagnetic valve III, 10-a vacuum degree detection device III, 11-a mechanical pump I, 12-a switch valve I, 13-a switch valve II, 14-an electromagnetic valve IV, 15-a vacuum degree detection device IV, 16-a roots pump II, 17-an electromagnetic valve V, 18-a vacuum degree detection device V, 19-a mechanical pump II, 20-an emptying device, 21-a control system, 22-a frequency converter, 23-a contactor, 24-a variable frequency motor, 25-an asynchronous motor, 27-a vacuum degree acquisition channel and 28-a valve position acquisition channel, 29-Pump feedback acquisition channel.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not intended to limit the invention in any way, and any variations or modifications which are based on the teachings of the invention are intended to be within the scope of the invention.

As shown in figures 1, 2 and 3, the automatic vacuum-pumping device of the electron beam cold hearth furnace comprises a vacuum degree detection device I2, an electromagnetic valve I3, a booster pump 4, an electromagnetic valve II 6, a vacuum degree detection device II 7, a Roots pump I8, an electromagnetic valve III 9, a vacuum degree detection device III 10, a mechanical pump I11, an electromagnetic valve IV 14, a vacuum degree detection device IV 15, a Roots pump II 16, an electromagnetic valve V17, a vacuum degree detection device V18, a mechanical pump II 19, an emptying device 20 and a control system 21, wherein the electromagnetic valve I3 is communicated with a vacuum-pumping port of a feeding bin 1 of the electron beam cold hearth furnace and is connected with the vacuum degree detection device I2 in parallel, the other end of the electromagnetic valve I3 is communicated with the booster pump 4, the other end of the booster pump 4 is respectively communicated with the electromagnetic valve II 6 and the electromagnetic valve IV 14, the electromagnetic valve II 6, the Roots pump I8, the electromagnetic valve III 9 and the mechanical pump I11 are sequentially communicated, a vacuum degree detection device II 7 is connected in parallel between the electromagnetic valve II 6 and the Roots pump I8, and a vacuum degree detection device III 10 is connected in parallel between the electromagnetic valve III 9 and the mechanical pump I11; the electromagnetic valve IV 14, the roots pump II 16, the electromagnetic valve V17 and the mechanical pump II 19 are sequentially communicated, a vacuum degree detection device IV 15 is connected in parallel between the electromagnetic valve IV 14 and the roots pump II 16, and a vacuum degree detection device V18 is connected in parallel between the electromagnetic valve V17 and the mechanical pump II 19; the output ends of the mechanical pump I11 and the mechanical pump II 19 are communicated with an emptying device 20, the output ends of the vacuum degree detection device I2, the vacuum degree detection device II 7, the vacuum degree detection device III 10, the vacuum degree detection device IV 15 and the vacuum degree detection device V18 are respectively and electrically connected with the input end of a control system 21, and the control ends of the electromagnetic valve I3, the booster pump 4, the electromagnetic valve II 6, the roots pump I8, the electromagnetic valve III 9, the mechanical pump I11, the electromagnetic valve IV 14, the roots pump II 16, the electromagnetic valve V17 and the mechanical pump II 19 are respectively and electrically connected with the output end of the control system 21.

The feeding bin 1 of the electron beam cold bed furnace is provided with at least two vacuumizing ports, each vacuumizing port of the feeding bin 1 is sequentially communicated with an electromagnetic valve I3 and a booster pump 4, and outlet ends of the booster pumps 4 connected with the vacuumizing ports of the feeding bin 1 are communicated with an electromagnetic valve II 6 and an electromagnetic valve IV 14 respectively after being communicated with each other.

An oil receiver 5 is arranged between the booster pump 4 and the electromagnetic valve II 6 and between the booster pump 4 and the electromagnetic valve IV 14, and the inlet end of the oil receiver 5 is communicated with the booster pump 4 while the outlet end is respectively communicated with the electromagnetic valve II 6 and the electromagnetic valve IV 14. The oil receiver 5 can prevent oil mist from entering the vacuum pipeline in large quantity, damaging pipeline equipment and directly discharging to cause air pollution.

The outlet end of the oil receiver 5 is also communicated with the inlet end of a switch valve I12 and/or a switch valve II 13, the outlet end of the switch valve I12 is communicated with the inlet end of a solenoid valve III 9, and the outlet end of the switch valve II 13 is communicated with the inlet end of a solenoid valve V17.

As shown in fig. 2, the present invention further includes a frequency converter 22 and a contactor 23 electrically connected to a control end of the control system 21, the roots pump i 8 and the mechanical pump i 11 are respectively connected to a variable frequency motor 24, the roots pump ii 16 and the mechanical pump ii 19 are respectively connected to an asynchronous motor 25, a power end of the variable frequency motor 24 is electrically connected to a driving output end of the frequency converter 22, a power control end of the asynchronous motor 25 is electrically connected to the contactor 23, and the control system 21 performs device interlocking and safety interlocking on each pump and each valve according to preset settings.

The power supply ends of the electromagnetic valves I3, II 6, III 9, IV 14 and V17 are respectively electrically connected with the contactor 23, and the valve position signal output ends of the electromagnetic valves are respectively electrically connected with the input end of the control system 21.

The booster pump 4, the roots pump I8, the mechanical pump I11, the roots pump II 16 and the mechanical pump II 19 are respectively provided with a pump signal feedback unit and are electrically connected with the input end of the control system 21.

The control system 21 is a PLC, a PC or an industrial personal computer.

The output ends of the vacuum degree detection device I2, the vacuum degree detection device II 7, the vacuum degree detection device III 10, the vacuum degree detection device IV 15 and the vacuum degree detection device V18 are respectively connected with a vacuum degree acquisition channel 27 of the control system 21.

And the valve position signal output ends of the electromagnetic valve I3, the electromagnetic valve II 6, the electromagnetic valve III 9, the electromagnetic valve IV 14 and the electromagnetic valve V17 are respectively in signal connection with a valve position acquisition channel 28 of the control system 21.

And pump signal feedback units of the booster pump 4, the roots pump I8, the mechanical pump I11, the roots pump II 16 and the mechanical pump II 19 are respectively in signal connection with a pump feedback acquisition channel 29 of the control system 21.

The starting control method of the automatic vacuumizing device of the electron beam cold hearth furnace comprises the steps of booster pump control, Roots pump II control, mechanical pump II control, Roots pump I control and mechanical pump I control, and specifically comprises the following steps:

A. and (3) booster pump control: the control system 21 controls the electromagnetic valve I3 to be opened, then the booster pump 4 is started, and when the detection value of the vacuum degree detection device I2 reaches a set value, a starting ready signal of the Roots pump II 16 is output;

B. and a Roots pump II: the control system 21 controls the electromagnetic valve IV 14 to be opened and starts the roots pump II 16, and outputs a starting ready signal of the mechanical pump II 19 when the detection value of the vacuum degree detection device IV 15 reaches a set value;

C. and (4) controlling a mechanical pump II: the control system 21 controls the electromagnetic valve V17 to be opened and starts the mechanical pump II 19, and when the detection value of the vacuum degree detection device V18 is read to reach a set value, a ready signal is started by the output frequency converter 22;

D. and (3) controlling a Roots pump I: the control system 21 controls the electromagnetic valve II 6 to be opened and controls the frequency converter 22 to start the Roots pump I8, reads a detection value of the vacuum degree detection device II 7, and then controls the frequency output to the Roots pump I8 by the frequency converter 22 to change along with the vacuum degree detection value;

E. and (3) controlling a mechanical pump I: the control system 21 controls the electromagnetic valve III 9 to be opened and controls the frequency converter 22 to start the mechanical pump I11, reads the detection value of the vacuum degree detection device III 10, and controls the frequency output to the mechanical pump I11 by the frequency converter 22 to change along with the detection value of the vacuum degree.

When the roots pump I8 and/or the roots pump II 16 are in fault or need to be closed in standby mode, the control system 21 controls the corresponding switch valve I12 and the corresponding switch valve II 13 to be opened, then stops the roots pump I8 and/or the roots pump II 16, and finally closes the corresponding electromagnetic valve II 6 and the corresponding electromagnetic valve IV 14.

In each step of the invention, if the detection value of the vacuum degree detection device is not changed or does not reach the set value after the pump is started, the sealing condition of the corresponding pipeline is checked.

Example 1

1. The system is electrified for self-checking, the control system 21 automatically controls the electromagnetic valves I3 communicated with the vacuumizing ports on the left side and the right side of the feeding bin 1 to be opened, then the booster pump 4 is started, the detection value of the vacuum degree detection device I2 is read in real time or at intervals, and when the detection value reaches a set value, a ready signal for starting the roots pump II 16 is output. 2. The control system 21 controls the electromagnetic valve IV 14 to be opened and starts the roots pump II 16, reads the detection value of the vacuum degree detection device IV 15, and outputs a starting ready signal of the mechanical pump II 19 when the detection value reaches a set value.

3. The control system 21 controls the electromagnetic valve V17 to be opened and starts the mechanical pump II 19, reads the detection value of the vacuum degree detection device V18, and outputs a ready signal for starting the frequency converter 22 when the detection value reaches a set value.

4. The control system 21 controls the electromagnetic valve II 6 to be opened and controls the frequency converter 22 to start the roots pump I8, reads the detection value of the vacuum degree detection device II 7, and then controls the frequency output by the frequency converter 22 to the roots pump I8 to change along with the detection value of the vacuum degree so as to maintain the detection value within the set range.

5. The control system 21 controls the electromagnetic valve III 9 to be opened and controls the frequency converter 22 to start the mechanical pump I11, reads the detection value of the vacuum degree detection device III 10, and controls the frequency output by the frequency converter 22 to the mechanical pump I11 to change along with the detection value of the vacuum degree so as to maintain the detection value within a set range.

Example 2

1. The system is electrified for self-checking, the control system 21 automatically controls the electromagnetic valves I3 communicated with the vacuumizing ports on the left side and the right side of the feeding bin 1 to be opened, then the booster pump 4 is started, the detection value of the vacuum degree detection device I2 is read in real time or at intervals, and when the detection value reaches a set value, a ready signal for starting the roots pump II 16 is output. If the detection value of the vacuum degree detection device I2 does not change or does not reach the set value within the preset time after the booster pump 4 is started, an alarm is given to prompt the sealing condition of the front pipeline and the rear pipeline of the booster pump 4 to be checked.

2. The control system 21 controls the electromagnetic valve IV 14 to be opened and starts the roots pump II 16, reads the detection value of the vacuum degree detection device IV 15, and outputs a starting ready signal of the mechanical pump II 19 when the detection value reaches a set value. When the roots pump II 16 is in fault or standby, the control system 21 firstly controls the switch valve II 13 to be opened, then stops the roots pump II 16, and finally closes the electromagnetic valve IV 14 to form a bypass vacuumizing state. And if the detection value of the vacuum degree detection device IV 15 is not changed or does not reach the set value within the preset time after the roots pump II 16 is started, alarming and prompting to check the pipeline sealing condition between the electromagnetic valves IV 14 and V17.

3. The control system 21 controls the electromagnetic valve V17 to be opened and starts the mechanical pump II 19, reads the detection value of the vacuum degree detection device V18, and outputs a ready signal for starting the frequency converter 22 when the detection value reaches a set value. If the detection value of the vacuum degree detection device V18 is unchanged or does not reach the set value within the preset time after the mechanical pump II 19 is started, an alarm is given to prompt the pipeline sealing condition after the electromagnetic valve V17 is checked.

4. The control system 21 controls the electromagnetic valve II 6 to be opened and controls the frequency converter 22 to start the roots pump I8, reads the detection value of the vacuum degree detection device II 7, and then controls the frequency output by the frequency converter 22 to the roots pump I8 to change along with the detection value of the vacuum degree so as to maintain the detection value within the set range. When the roots pump I8 breaks down or is in standby, the control system 21 firstly controls the switch valve I to be opened, then stops the roots pump I8, and finally closes the electromagnetic valve II 6 to form a bypass vacuumizing state. If the detection value of the vacuum degree detection device II 7 is unchanged or does not reach the set value within the preset time after the roots pump I8 is started, the pipeline sealing condition between the electromagnetic valves II 6 and III 9 is detected through alarm prompt.

5. The control system 21 controls the electromagnetic valve III 9 to be opened and controls the frequency converter 22 to start the mechanical pump I11, reads the detection value of the vacuum degree detection device III 10, and controls the frequency output by the frequency converter 22 to the mechanical pump I11 to change along with the detection value of the vacuum degree so as to maintain the detection value within a set range. If the detection value of the vacuum degree detection device III 10 does not change or does not reach the set value within the preset time after the mechanical pump I11 is started, an alarm is given to prompt the user to check the pipeline sealing condition after the electromagnetic valve III 9.