CN201344125Y

CN201344125Y - Roots vacuum pump

Info

Publication number: CN201344125Y
Application number: CNU2009201429748U
Authority: CN
Inventors: 冯新伟
Original assignee: Jiangsu Jinton Advanced Optics & Elec Display Tech Co Ltd
Current assignee: Jiangsu Jinton Advanced Optics & Elec Display Tech Co Ltd
Priority date: 2009-02-05
Filing date: 2009-02-05
Publication date: 2009-11-11
Anticipated expiration: 2019-02-05

Abstract

The utility model discloses a Roots vacuum pump used for pumping a vacuum cavity in a vacuum system. The Roots vacuum pump includes a pump body provided with a suction area and an exhaust area; and a channel is arranged between the suction area and the exhaust area and can be opened or closed through a pneumatic controllable valve. The utility model adopts the pneumatic controllable valve to control the opening or the closing of the channel between the suction area and the exhaust area; the channel is opened when a prepump performs air pre-suction to the vacuum cavity, and the air of the suction area can pass through the channel directly and be taken away through the exhaust area, so that the time for the prepump pumping from the atmospheric condition to the pressure for Roots vacuum pump starts working is shorted greatly. Therefore, the production efficiency is improved.

Description

Roots pump

Technical field

The utility model relates to the vacuum equipment technical field, especially a kind of Roots pump.

Background technique

As everyone knows, Roots pump must could start after atmospheric pressure is less than 10 kPas, Roots pump commonly used all has a relief valve that is installed between air draught district and the exhaust zone, to prevent Roots pump motor long term overloading operation when pressure reduction is excessive between air draught district and the exhaust zone, when Roots pump is worked, pumped gas enters in the seal chamber of pump from suction port, from the rotor that is " 8 " shape and the cavity between the pump case, pass through again, arrive relief opening, taken away by fore pump, less as pressure reduction between air draught district and the exhaust zone, then gas is directly taken away by fore pump, by the seal ring that is located at the relief valve bottom degree of vacuum is guaranteed simultaneously, bigger as pressure reduction, reach the deadweight of the active force of relief valve valve body bottom surface greater than the relief valve valve body, then the relief valve valve body is backed down, portion gas is returned suction port, thus the not long term overloading operation of protection Roots pump motor; But when Roots pump is not worked, almost there is not pressure difference between air draught district and the exhaust zone, relief valve is failure to actuate, all gases from the suction port suction can only pass through from the gap between rotor of " 8 " shape, this gap generally has only about 0.2mm, so, when Roots pump is not worked, this gap just becomes the restriction to the fore pump pumping speed on the contrary, thereby prolonged the starting time of Roots pump, reduced manufacturing efficiency, if do threeway and increase valve from the prime pump steam inlet, pipeline etc. directly be evacuated cavity and be connected, also can realize improving the purpose of pumping speed, but from the integrity of equipment, the aspects such as degree-of-difficulty factor of safety reliability and transformation are considered, are not too economical suitable.

The model utility content

The purpose of this utility model is: a kind of Roots pump is provided, it can improve the pre-pumping speed of fore pump, fore pump is extracted into the air pressure in the vacuum system below the startup pressure of Roots pump within a short period of time, thereby reaches the purpose of enhancing productivity.

The technological scheme that its purpose that realizes the utility model adopts is: a kind of Roots pump, comprise the pump housing, have air draught district and exhaust zone in the pump housing, be provided with passage between air draught district and the exhaust zone, described passage is realized its unlatching by controllable valve or is closed, do not work at Roots pump, passage was an opening state when fore pump was bled in advance, Roots pump when work passage is a closed condition.

Described controllable valve is a pneumatic type.

The beneficial effects of the utility model are: the utility model employing pneumatic type controllable valve is controlled the unlatching of passage between air draught district and the exhaust zone or is closed, when fore pump is bled in advance, passage is open-minded, the gas in air draught district can directly be taken away by exhaust zone through passage, more originally shortened about 2/3 thereby make fore pump be extracted into the time that Roots pump starts operating pressure, improved manufacturing efficiency greatly from atmospheric conditions.

Description of drawings

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is a structural representation of the present utility model.

Fig. 2 is the structural representation that the utility model is applied to vacuum system.

Fig. 3 is the structural representation that vacuum system is applied to the continuous coating equipment system.

1. pump housings, 2. air draught districts, 3. exhaust zone, 4. passages, 5. controllable valves, 6. vacuum cavities, 7. sliding valve vacuum pumps, 8. Roots pumps, 9. high vacuum pumps 10. advance Transition Room slice chambers 15., 11. separation valve doors, 12. preceding Transition Room 13. coating chambers, 14. back, sheet chamber 16. bleed valves among the figure

Embodiment.

In conjunction with the accompanying drawings the utility model is further described now.These accompanying drawings are the schematic representation of simplification, basic structure of the present utility model only is described in a schematic way, so it only show the formation relevant with the utility model.

A kind of Roots pump as shown in Figure 1, comprise the pump housing 1, have air draught district 2 and exhaust zone 3 in the pump housing 1, be provided with passage 4 between air draught district 2 and the exhaust zone 3, described passage 4 is realized its unlatching by controllable valve 5 or closes that this controllable valve 5 adopts pneumatic type control.

Specifically, this Roots pump has reasonably utilized the structure of the Roots pump of original tape relief valve, the Roots pump of original tape relief valve is provided with relief valve between air draught district 2 and exhaust zone 3, after the relief valve that now will originally be provided with is removed, be provided with pneumatic type controllable valve 5 in situ, become a controllable passage 4, when Roots pump quits work, pneumatic type controllable valve 5 is opened, passage 4 areas are increased, flow resistance reduces, just can be taken away fast by fore pump by exhaust zone 3 at the gas in air draught district 2 like this through this passage 4, improved the pumping efficiency of fore pump thus, make fore pump the air pressure in the vacuum system is extracted into below the startup pressure of Roots pump within a short period of time, thereby reach the purpose of enhancing productivity, when Roots pump is started working, close by controllable valve 5 and to make passage 4 blocking-up, thereby guarantee the pumping speed and the degree of vacuum requirement of Roots pump, and the working state of pneumatic type controllable valve 5 is decided according to the working state of Roots pump, by the PLC program control, link with Roots pump.

Fig. 2 is the structural representation of vacuum system, in common vacuum system, in order to improve the speed of exhaust and to guarantee that vacuum cavity 6 reaches degree of vacuum requirement preferably, usually adopt the combining form of sliding valve vacuum pump 7+ Roots pump 8+ Roots pump 8+ high vacuum pump 9 to come vacuum cavity 6 is vacuumized, and Roots pump 8 and high vacuum pump 9 can not directly extract atmosphere, Roots pump 8 wherein must could start after pressure is less than 10 kPas, general work pressure is less than 4 kPas, during system works, be sliding valve vacuum pump 7 work earlier, air pressure in the system is evacuated under the pressure of Roots pump 8 startups, Roots pump 8 and high vacuum pump 9 begin successively, the degree of vacuum in the vacuum cavity 6 are extracted into meet the requirements.

Fig. 3 vacuum system is applied to the structural representation of continuous coating equipment system, during system works, at first under manual condition, the vacuum unit that intermediate coated film chamber 13 relies on sliding valve vacuum pump 7+ Roots pump 8+ Roots pump 8 to form is extracted into gas pressure intensity below 10 handkerchiefs, wherein when the vacuum unit begins to bleed under atmospheric conditions, pneumatic type controllable valve 5 on the Roots pump 8 is opened, do not reach about 4000 handkerchiefs because of pressure this moment, Roots pump 8 is not activated, pumped gas is the passage 4 arrival exhaust zone 3 about by the diameter 80mm of former overflow valve port from air draught district 2 just directly, taken away by prime sliding valve vacuum pump 7, effectively improved the pumping speed of sliding valve vacuum pump 7, made sliding valve vacuum pump 7 be extracted into the time that Roots pump 8 starts operating pressures and shortened about 2/3 from atmosphere; When Roots pump 8 was started working, controllable valve 5 was closed, and passage 4 blocking-up between air draught district 2 and the exhaust zone 3 have guaranteed the requirement of pumping speed He its ultimate vacuum of Roots pump 8.

Gas pressure intensity is being extracted into 10 handkerchiefs when following, high vacuum pump 9 work and high vacuum valve are opened the beginning pumping high vacuum, after reaching the requirement of technology degree of vacuum and reaching condition such as technological temperature, change auto-programming over to.At this moment, advancing the bleed valve 16 of sheet chamber 10 works under the condition that the separation valve door 11 that advances between sheet chamber 10 and the preceding transition chamber 12 is closed, enter sheet chamber 10 and become barometric pressure, workpiece enters into sheet chamber 10, and bleed valve 16 cuts out, unit work, to enter sheet chamber 10 is extracted into below 3 handkerchiefs, the separation valve door 11 that advances between sheet chamber 10 and the preceding transition chamber 12 is opened, and closes separation valve door 11 behind the transition chamber 12 before workpiece is sent into, and enters sheet chamber 10 and repeats venting again and connect workpiece.Before the workpiece of transition chamber 12 in the short stay preheating and extract because of after advancing the assorted gas that sheet chamber 10 poor vacuum cause, separation valve door 11 before opening between transition chamber 12 and the coating chamber 13, workpiece enters coating chamber 13 and carries out plated film, the workpiece behind the plated film through after transition chamber 14 cooling back send from slice chamber 15.

The manufacturing efficiency of continuous coating equipment system is except the influence of target surface power density, pumping efficiency when mainly being confined to rough vacuum unit work that sliding valve vacuum pump 7+ Roots pump 8+ Roots pump 8 forms, so will effectively enhance productivity, just must improve the pumping speed of rough vacuum unit more economically.

Claims

1. Roots pump, comprise the pump housing (1), have air draught district (2) and exhaust zone (3) in the pump housing (1), be provided with passage (4) between air draught district (2) and the exhaust zone (3), it is characterized in that: described passage (4) is realized its unlatching by controllable valve (5) or is closed.

2. Roots pump according to claim 1 is characterized in that: described controllable valve (5) is a pneumatic type.