CN109113991B - A kind of vertical rotors for dry double-screw vacuum pump having over-voltage degassing function - Google Patents

A kind of vertical rotors for dry double-screw vacuum pump having over-voltage degassing function Download PDF

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Publication number
CN109113991B
CN109113991B CN201811019843.0A CN201811019843A CN109113991B CN 109113991 B CN109113991 B CN 109113991B CN 201811019843 A CN201811019843 A CN 201811019843A CN 109113991 B CN109113991 B CN 109113991B
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China
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screw
pump housing
relief
pressure
relief hole
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CN109113991A (en
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蔡旭
张世伟
赵凡
孙坤
韩峰
谢元华
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Northeastern University China
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Northeastern University China
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/082—Details specially related to intermeshing engagement type pumps
    • F04C18/084—Toothed wheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/02—Pumps characterised by combination with or adaptation to specific driving engines or motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/24—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/12—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • F04C29/124—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet with inlet and outlet valves specially adapted for rotary or oscillating piston pumps

Abstract

A kind of vertical rotors for dry double-screw vacuum pump having over-voltage degassing function, screw rotor use the varying pitch rotor of double end holohedral symmetry molded line, and lead of screw gradually becomes smaller along pump housing air entry to exhaust outlet axis direction；Screw vacuum pump compression ratio is set as R, R > 3, R=Vin/Vout, VinFor aspirated volume of the screw rotor at pump housing air entry in 2 π helical angles, VoutFor delivery space of the pump housing exhaust ports screw rotor in 2 π helical angles；Relief hole is offered on side wall between pump housing air entry and exhaust outlet, each screw rotor is correspondingly arranged one group of relief hole, includes two rows of relief holes in every group；Pressure-releasing chamber at one is provided with outside the pump housing, pump housing inner cavity is communicated by relief hole with pressure-releasing chamber outside the pump housing；The external relief tube of pressure-releasing chamber, is provided with relief valve, relief tube is communicated with pump housing exhaust passage by relief valve or directly communicated with atmosphere on relief tube；When gas pressure is higher than pressure at expulsion at relief hole, relief valve is opened, and overcompression gas is discharged.

Description

A kind of vertical rotors for dry double-screw vacuum pump having over-voltage degassing function
Technical field
The invention belongs to rotors for dry double-screw vacuum pump technical fields, have the vertical of over-voltage degassing function more particularly to a kind of Rotors for dry double-screw vacuum pump.
Background technique
Rotors for dry double-screw vacuum pump is a kind of widely used dry vacuum pump, and the section of pump housing inner cavity is in the figure of eight, The screw rotor of a pair of of intermeshing and synchronous backward rotation is provided in pump housing inner cavity, according to the spiral expansion side of screw rotor The difference of formula, screw rotor are divided into uniform pitch rotor and varying pitch rotor, the lead of varying pitch rotor therein from suction end to Exhaust end gradually becomes smaller, pumping process have interior compression, compared with uniform pitch rotor, also have exhaust power consumption it is few, Many advantages, such as temperature is low, noise is small.
It is most all to use upper cantilever structure for vertical rotors for dry double-screw vacuum pump, it is therefore necessary to it is required that outstanding The screw rotor of arm section has good dynamic balance；For the rotors for dry double-screw vacuum pump using universal single thread rotor come It says, mass center of the screw rotor on each cross section is at eccentric position, therefore has natural unbalance response, It has to do special dynamic balancing amendment；And for the rotors for dry double-screw vacuum pump using varying pitch rotor, screw rod turns The disequilibrium of son becomes apparent, and dynamic balancing amendment will be more difficult.
For the rotors for dry double-screw vacuum pump using varying pitch rotor, the power consumption in pumping process can be divided into two Point, first part is to do compression power consumption required for interior compression to gas, and second part is by gas discharge pump housing exhaust outlet institute The exhaust power consumption needed.In one timing of pumping speed, the compression ratio of varying pitch rotor is bigger, then the compression power consumption of rotors for dry double-screw vacuum pump It is bigger, and it is smaller to be vented power consumption.
For long-term work for the rotors for dry double-screw vacuum pump using varying pitch rotor under critical pressure, using big Compression ratio can reduce exhaust power consumption, to obtain preferable energy-saving effect, still, be higher than the pumping of critical pressure in admission pressure Stage, rotors for dry double-screw vacuum pump can be there is a situation where pumping interior gas in overpressure contracting, i.e. gas compressed pressure in pump chamber is higher than Pressure at expulsion, this not only results in the increase of compression power consumption and the raising of gas temperature, and it is swollen to be also easy to initiation screw rotor volume It is swollen to scratch and situations such as screw rotor surface covering is fallen off.Therefore, how to evade the harm that gas in overpressure contracts, be The technical problem for needing emphasis to solve in design, production and use process using the rotors for dry double-screw vacuum pump of varying pitch rotor.
In order to evade the harm of gas in overpressure contracting, there are two types of presently the most common counter-measures:
1., in the structured design phase of rotors for dry double-screw vacuum pump, the artificial compression ratio for controlling varying pitch rotor, compression ratio is logical Often both less than 2:1, can so play balance compression power consumption and be vented power consumption purpose, still, disadvantage be also it is fairly obvious, Firstly, since cannot achieve bigger compression ratio, thus will be unable to give full play of rotors for dry double-screw vacuum pump energy conservation, cooling, Potential ability in terms of noise reduction；Secondly, there is overcompression situations always in high inlet pressure, and need to configure high-power Motor, can not only generate big power consumption and high temperature exothermic, cause the waste of the energy, and be easy to cause failure.
2., in rotors for dry double-screw vacuum pump operational process, using variable-frequency power sources and variable-frequency motor, and in high inlet pressure Carry out low frequency reduction of speed, although still remaining overcompression situation when high inlet pressure, can protect to control control suction power Card motor will not overload fever, nevertheless, low frequency fall-back can directly result in the actually active of rotors for dry double-screw vacuum pump Pumping speed decline so that the pumpdown time in high pressure stage be made to extend, and causes pumping efficiency reduction and energy consumption to increase.
For this purpose, notification number provides another solution for the patent application of CN102395793A, on pump housing side wall Multiple over-voltage outlets have been opened up, spherical excess pressure valve is installed in over-voltage exit, when the gas pressure for pumping interior suction chamber is compressed into When sufficiently large, then it can push spherical excess pressure valve open and flow out, to avoid the generation of overcompression.
But clearly set out over-voltage outlet to open up position in above-mentioned patent application, keeps it real in guidance Operability in the design of border is deteriorated, this is one of the main reason for this technology is not used actually yet so far；Above-mentioned patent Application is originated from the exhaust valve knot of various oil sealing vacuums pump using the scheme for directly installing spherical excess pressure valve in over-voltage exit Structure, and spherical excess pressure valve carries out repeating reset by own wt, but excess pressure valve closing easily occurs under the conditions of oil-free Not tight failure is inevitably resulted in export in subsequent pumping process by over-voltage and be returned into pump once excess pressure valve is not closed completely Leakage is flowed, to cause the pumping speed and final vacuum decline of pump；It, can be with further more, spherical excess pressure valve is opening working stage Very big noise occurs, and can bring adverse effect to field personnel；In addition, the multistage over-voltage outlet of above-mentioned patent application is equal It is connected by the independent interface channel of same with pump inner cavity, is easily occurred because of spherical excess pressure valve simultaneously between each hole of front stage It opens and the failure of mutually " collaborating ", causes to pump interior pumped gas and generated by interface channel and circulate；In addition, above-mentioned patent The interface channel of the over-voltage outlet of application extends along the length direction of the entire pump housing, this necessarily will affect the cloth of pump housing cold water jacket It sets, and cold water jacket arrangement is bad, inevitably results in the raising of cooling effect decline and pump body temperature.
Summary of the invention
In view of the problems of the existing technology, it is true to provide a kind of vertical oil free screw for having over-voltage degassing function by the present invention The screw serrated form profile of sky pump, screw rotor uses double end holohedral symmetry molded line, and screw rotor has been effectively ensured every Mass center on one cross section is at its rotation center, and screw rotor is made to be provided with self-balancing attribute, from eliminating at all Unbalanced factor；The screw vacuum pump can be realized bigger compression ratio, to reduce exhaust power consumption, while allow to configure small function Rate motor can guarantee that screw vacuum pump operates normally in entire suction pressure section, especially to improve energy-saving effect It is that in high inlet pressure overcompression and overload heating problem can will not occur, make the pumping in high pressure stage with full speed running Time is greatly shortened, and effectively increases pumping efficiency.
To achieve the goals above, the present invention adopts the following technical scheme: a kind of vertical nothing for having over-voltage degassing function Oily screw vacuum pump is passed including the pump housing, the screw rotor of a pair of of intermeshing and synchronous backward rotation, synchromesh gear group, power Defeated gear set and motor；The inner cavity that section is in the figure of eight is equipped in the pump housing, the screw rotor is located at pump housing inner cavity In, and two screw rotors use upper cantilever parallel vertical supporting way, the synchromesh gear group is connected to two screw rotors Lower shaft end, the motor shaft of the motor mutually consolidated by the lower shaft end of power transmission gear set and a wherein screw rotor Even；Its main feature is that: the screw serrated form profile of the screw rotor uses double end holohedral symmetry molded line, and screw rotor is using change The lead of screw of screw pitch rotor, screw rotor gradually becomes smaller along the axis direction of pump housing air entry to exhaust outlet；Screw vacuum pump Compression ratio be set as R, and R > 3, wherein R=Vin/Vout, in formula, VinIt is screw rotor at pump housing air entry in 2 π helical angles Interior aspirated volume, VoutFor delivery space of the pump housing exhaust ports screw rotor in 2 π helical angles；In the pump housing air entry Relief hole is offered on pump housing side wall between exhaust outlet, and each screw rotor is correspondingly arranged one group of relief hole, often Include two rows of relief holes in group；Pressure-releasing chamber at one is provided with outside the pump housing, pump housing inner cavity passes through outside relief hole and the pump housing The pressure-releasing chamber in portion communicates；The external relief tube of pressure-releasing chamber, is provided with relief valve, relief tube passes through pressure release on relief tube Valve is communicated with pump housing exhaust passage or is directly communicated with atmosphere.
The quantity at least two of relief hole described in every group, the shape of relief hole are round hole or slot apertures.
Pump down volume of the screw rotor in 2 π helical angles is set as V at the relief holem, and Vm=Vin/R1/2, in formula, Vin For aspirated volume of the screw rotor at pump housing air entry in 2 π helical angles, R is the compression ratio of screw vacuum pump.
Distribution mode of the relief hole described in every group on pump housing side wall is helically linear, and the helically pressure release of the distribution of line shape The rotation direction and helix angle in hole are identical as the rotation direction of the screw rotor of corresponding position and helix angle.
When the shape of the relief hole is round hole, the diameter of relief hole is less than the tooth of the screw rotor of corresponding position Top surface width；When the shape of the relief hole is slot apertures, the width of relief hole is less than the screw rotor of corresponding position Topland width.
When the screw rotor rotates to a particular moment, which meets the following conditions: screw rotor Crest top land covers whole relief holes, under the particular moment, after screw rotor continues to be rotated by 90 °, and whole relief holes Get rid of the masking of screw rotor crest top land.
The lead of screw of the screw rotor has along the gradually smaller rule of axis direction of pump housing air entry to exhaust outlet Two kinds, linearly to become smaller, second is that segmentation phase step type becomes smaller for the first.
The relief valve is using automatic control vaccum stop valve or manually controls vaccum stop valve.
When gas pressure at the relief hole is higher than pressure at expulsion, relief valve is opened, and the gas of overcompression successively leads to Relief hole, pressure-releasing chamber, relief tube and relief valve discharge are crossed, when the gas pressure at relief hole is no longer above pressure at expulsion, Relief valve closure pumps interior gas and is all discharged by the exhaust outlet of the pump housing.
Pressure sensor is installed at the air entry of the pump housing, or pressure sensing is installed at the relief hole of the pump housing Device；When pressure sensor is located at pump housing air entry, pump inlet pressure is detected by pressure sensor, when pump inlet pressure height When critical pressure, relief valve is opened；Critical pressure is set as Pk, and Pk=Pout/R1/2~Pout/Rk/2, in formula, PoutFor pump exhaust Pressure, R are the compression ratio of screw vacuum pump, and k is the adiabatic coefficent of gas；When pressure sensor is located at pump housing relief hole, The gas pressure at relief hole is detected by pressure sensor, when the gas pressure at relief hole is higher than pressure at expulsion, pressure release Valve is opened.
Beneficial effects of the present invention:
The vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function of the invention, the screw serrated form end face of screw rotor Molded line uses double end holohedral symmetry molded line, and mass center of the screw rotor on each cross section has been effectively ensured and has been at its rotation Turn center, screw rotor is made to be provided with self-balancing attribute, from eliminating unbalanced factor at all；Vertical oil free screw of the invention Vacuum pump, only opens up level-one relief hole and a pressure-releasing chamber, and overcompression gas exhaust path is that relief hole → pressure-releasing chamber → is let out Pressure pipe → relief valve, relief valve are placed outside outside the pump housing, occupancy pump housing outer wall area that will not be excessive, therefore will not influence the pump housing The normal arrangement and water-cooled effect of water-cooled jacket；Relief valve of the invention is using automatic control vaccum stop valve or manually controls vacuum Shut-off valve, it is ensured that realize reliable sealing after closing under the conditions of oil-free, prevent extraneous gas by relief hole into pump It backflows leakage；For two groups of relief holes corresponding to two screw rotors, it is in gas pressure workspace in identical pump, it can The masking of two screw rotor crest top lands is covered or be detached from simultaneously by two screw rotor crest top land simultaneously, therefore between relief hole It will not there is a situation where mutual " collaborating "；The present invention is based on thermodynamic optimization calculating, give relief hole and most preferably open along axial If position, so that vertical rotors for dry double-screw vacuum pump of the invention is can be realized bigger compression ratio, can effectively reduce exhaust power consumption, together When allow to configure more low power motor, effectively increase energy-saving effect, while can guarantee that screw vacuum pump is entirely being taken out It is operated normally in atmospheric pressure section, especially overcompression and overload hair can will not occur with full speed running in high inlet pressure Heat problem is greatly shortened the pumpdown time in high pressure stage, energy consumption reduction, effectively increases pumping efficiency；By this hair It is bright to instruct actual design, it can be realized the best configuration of motor and the optimization operation of screw vacuum pump.
Detailed description of the invention
Fig. 1 is the vertical rotors for dry double-screw vacuum pump structural schematic diagram for having over-voltage degassing function of the embodiment of the present invention one；
Fig. 2 is schematic diagram of the relief hole by screw rotor crest top land when completely obscured in the embodiment of the present invention one；
Fig. 3 is A direction view in Fig. 2；
Fig. 4 is that relief hole is completely free of schematic diagram when screw rotor crest top land covers in the embodiment of the present invention one；
Fig. 5 is B direction view in Fig. 4；
Fig. 6 is the vertical rotors for dry double-screw vacuum pump structural schematic diagram for having over-voltage degassing function of the embodiment of the present invention two；
Fig. 7 is schematic diagram of the relief hole by screw rotor crest top land when completely obscured in the embodiment of the present invention two；
Fig. 8 is C direction view in Fig. 7；
Fig. 9 is that relief hole is completely free of schematic diagram when screw rotor crest top land covers in the embodiment of the present invention two；
Figure 10 is D direction view in Fig. 9；
In figure, the 1-pump housing, 2-screw rotors, 3-synchromesh gear groups, 4-power transmission gear sets, 5-motor, 6-air entries, 7-exhaust outlets, 8-relief holes, 9-pressure-releasing chambers, 10-relief tubes, 11-relief valves, 12-pressure sensors.
Specific embodiment
The present invention is described in further detail in the following with reference to the drawings and specific embodiments.
As shown in Fig. 1~10, a kind of vertical rotors for dry double-screw vacuum pump having over-voltage degassing function, including the pump housing 1, a pair Screw rotor 2, synchromesh gear group 3, power transmission gear set 4 and the motor 5 of intermeshing and synchronous backward rotation；Described Equipped with section in the inner cavity of the figure of eight in the pump housing 1, the screw rotor 2 is located in 1 inner cavity of the pump housing, and two screw rotors 2 are adopted With upper cantilever parallel vertical supporting way, the synchromesh gear group 3 is connected to the lower shaft end of two screw rotors 2, described electronic The motor shaft of machine 5 is fixedly connected with by power transmission gear set 4 and the lower shaft end of a wherein screw rotor 2；The screw rotor 2 Screw serrated form profile use double end holohedral symmetry molded line, and screw rotor 2 use varying pitch rotor, the spiral shell of screw rotor 2 Rotation lead gradually becomes smaller along the axis direction of the pump housing 1 air entry 6 to exhaust outlet 7；The compression ratio of screw vacuum pump is set as R, and R > 3, wherein R=Vin/Vout, in formula, VinFor aspirated volume of the screw rotor 2 in 2 π helical angles at 1 air entry 6 of the pump housing, Vout Go out delivery space of the screw rotor 2 in 2 π helical angles for 1 exhaust outlet 7 of the pump housing；The pump housing 1 air entry 6 and exhaust outlet 7 it Between pump housing side wall on offer relief hole 8, and each screw rotor 2 is correspondingly arranged one group of relief hole 8, includes in every group Two rows of relief holes 8；Pressure-releasing chamber 9 at one are provided with outside the pump housing 1,1 inner cavity of the pump housing passes through outside relief hole 8 and the pump housing 1 Pressure-releasing chamber 9 communicate；9 external relief tubes 10 of the pressure-releasing chamber, are provided with relief valve 11, relief tube 10 on relief tube 10 It is communicated by relief valve 11 with pump housing exhaust passage or is directly communicated with atmosphere.
The quantity at least two of relief hole 8 described in every group, the shape of relief hole 8 are round hole or slot apertures.
Pump down volume of the screw rotor 2 in 2 π helical angles is set as V at the relief hole 8m, and Vm=Vin/R1/2, in formula, VinFor aspirated volume of the screw rotor 2 in 2 π helical angles at 1 air entry 6 of the pump housing, R is the compression ratio of screw vacuum pump.
Distribution mode of the relief hole 8 on pump housing side wall described in every group be helically linear, and helically the distribution of line shape is let out Press rotation direction and the helix angle in hole 8 identical as the rotation direction of the screw rotor 2 of corresponding position and helix angle.
When the shape of the relief hole 8 is round hole, the diameter of relief hole 8 is less than the screw rotor 2 of corresponding position Topland width；When the shape of the relief hole 8 is slot apertures, the width of relief hole 8 is less than the screw rod of corresponding position The topland width of rotor 2.
When the screw rotor 2 rotates to a particular moment, which meets the following conditions: screw rotor 2 Crest top land whole relief holes 8 are covered, under the particular moment, after screw rotor 2 continues to be rotated by 90 °, all let out Pressure hole 8 gets rid of the masking of 2 crest top land of screw rotor.
Axis direction gradually smaller rule of the lead of screw of the screw rotor 2 along the pump housing 1 air entry 6 to exhaust outlet 7 There are two types of rules, and, linearly to become smaller, second is that segmentation phase step type becomes smaller for the first.
The relief valve 11 is using automatic control vaccum stop valve or manually controls vaccum stop valve.
When gas pressure at the relief hole 8 is higher than pressure at expulsion, relief valve 11 is opened, and the gas of overcompression is successively It is discharged by relief hole 8, pressure-releasing chamber 9, relief tube 10 and relief valve 11, the gas pressure at relief hole 8 is no longer above row When atmospheric pressure, relief valve 11 is closed, and is pumped interior gas and is all discharged by the exhaust outlet of the pump housing 1.
Pressure sensor 12 is installed at the air entry 6 of the pump housing 1, or pressure is installed at the relief hole 8 of the pump housing 1 Sensor 12；When pressure sensor 12 is located at 1 air entry 6 of the pump housing, pump inlet pressure is detected by pressure sensor 12, when When pump inlet pressure is higher than critical pressure, relief valve 11 is opened；Critical pressure is set as Pk, and Pk=Pout/R1/2~Pout/Rk/2, formula In, PoutTo pump pressure at expulsion, R is the compression ratio of screw vacuum pump, and k is the adiabatic coefficent of gas；When pressure sensor 12 is located at When at 1 relief hole 8 of the pump housing, the gas pressure at relief hole 8 is detected by pressure sensor 12, the gas pressure at relief hole 8 When power is higher than pressure at expulsion, relief valve 11 is opened.
Embodiment one:
As shown in Fig. 1~5, in the present embodiment, screw rotor 2 is cross-section three-stage varying pitch screw, screw rotor 2 Lead of screw becomes smaller along three sections of phase step types of axis direction point of 1 air entry 6 of the pump housing to exhaust outlet 7, and the air-breathing of screw rotor 2 Section, compression section and exhaust section are respectively the uniform pitch section that lead of screw successively becomes smaller, and the compression ratio R of screw vacuum pump is set as 4, and And the position that opens up of relief hole 8 meets Vin/Vm=2, the shape of relief hole 8 is round hole, and the quantity of every group of relief hole 8 is 8 (quantity of every row's relief hole 8 is 4, and the total quantity of two groups of relief holes 8 is 16), relief valve 11 is cut using vacuum is automatically controlled Only valve, specific to select GID type electric vacuum valve, relief tube 10 is communicated by relief valve 11 with pump housing exhaust passage, in the pump housing 1 Pressure sensor 12 is installed at air entry 6.
Start screw vacuum pump, carry out vacuumizing operation, with the progress for vacuumizing operation, when pressure sensor 12 detects When being higher than critical pressure to pump inlet pressure, relief valve 11 is automatically turned on, and the gas of overcompression will pass sequentially through relief hole 8, let out Chamber 9, relief tube 10 and relief valve 11 is pressed to be discharged, when the gas pressure at relief hole 8 is no longer above pressure at expulsion, and when pressure When force snesor 12 detects pump inlet pressure lower than critical pressure, relief valve 11 is closed automatically, pumps interior gas all by the pump housing 1 Exhaust outlet 7 be discharged.
Embodiment two:
As shown in Fig. 6~10, in the present embodiment, screw rotor 2 is cross-section three-stage varying pitch screw, screw rotor 2 Lead of screw become smaller along axis direction point three sections of phase step types of 1 air entry 6 of the pump housing to exhaust outlet 7, and the air-breathing of screw rotor 2 Section, compression section and exhaust section are respectively the uniform pitch section that lead of screw successively becomes smaller, and the compression ratio R of screw vacuum pump is set as 6, and And the position that opens up of relief hole 8 meets Vm=Vin/61/2, the shape of relief hole 8 is a slot apertures, and the quantity of every group of relief hole 8 is 4 A (quantity of every row's relief hole 8 is 2, and the total quantity of two groups of relief holes 8 is 8), relief valve 11 uses and manually controls vacuum Shut-off valve, specific to select GU type manual vacuum ball valve, relief tube 10 is directly communicated with atmosphere by relief valve 11, and in relief valve Fasten a soft ribbon in 11 exit.
Before starting screw vacuum pump, first manually opened relief valve 11, then restarts screw vacuum pump, take out true Idle job observes the direction of waving of 11 exit ribbon of relief valve, for showing airflow direction；Operation early period is being vacuumized, it can To see that the direction of waving of ribbon is outwardly, to illustrate that gas flows outwardly, with the progress for vacuumizing operation, it is by taking out Pressure in system gradually decreases, and waves when the ribbon for observing 11 exit of relief valve tapers off, even becomes floaing inwardly It is dynamic, illustrate that gas has stopped flowing outwardly, relief valve 11 is turned off manually at this time.
The scope of patent protection that scheme in embodiment is not intended to limit the invention, it is all without departing from carried out by the present invention etc. Effect implements or change, is both contained in the scope of the patents of this case.

Claims (10)

1. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function, including the pump housing, a pair are intermeshed and synchronize anti- To the screw rotor of rotation, synchromesh gear group, power transmission gear set and motor；It is in " 8 " that section is equipped in the pump housing The inner cavity of font, the screw rotor are located in pump housing inner cavity, and two screw rotors use upper cantilever parallel vertical support side Formula, the synchromesh gear group are connected to the lower shaft end of two screw rotors, and the motor shaft of the motor passes through power transmission tooth Wheel group and the lower shaft end of a wherein screw rotor are fixedly connected with；It is characterized by: the screw serrated form face type of the screw rotor Line uses double end holohedral symmetry molded line, and screw rotor uses varying pitch rotor, and the lead of screw of screw rotor is along pump housing air entry Axis direction to exhaust outlet gradually becomes smaller；The compression ratio of screw vacuum pump is set as R, and R > 3, wherein R=Vin/Vout, formula In, VinFor aspirated volume of the screw rotor at pump housing air entry in 2 π helical angles, VoutExist for pump housing exhaust ports screw rotor Delivery space in 2 π helical angles；Relief hole is offered on pump housing side wall between the pump housing air entry and exhaust outlet, and Each screw rotor is correspondingly arranged one group of relief hole, includes two rows of relief holes in every group；It is provided with outside the pump housing Pressure-releasing chamber at one, pump housing inner cavity are communicated by relief hole with the pressure-releasing chamber outside the pump housing；The external relief tube of pressure-releasing chamber, Relief valve is provided on relief tube, relief tube is communicated with pump housing exhaust passage by relief valve or directly communicated with atmosphere.
2. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: The quantity at least two of relief hole described in every group, the shape of relief hole are round hole or slot apertures.
3. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: Pump down volume of the screw rotor in 2 π helical angles is set as V at the relief holem, and Vm=Vin/R1/2, in formula, VinFor pump housing suction Aspirated volume of the screw rotor in 2 π helical angles at port, R are the compression ratio of screw vacuum pump.
4. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: Distribution mode of the relief hole described in every group on pump housing side wall is helically linear, and the helically rotation direction of the relief hole of the distribution of line shape It is identical as the rotation direction of the screw rotor of corresponding position and helix angle with helix angle.
5. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: When the shape of the relief hole is round hole, the crest top land that the diameter of relief hole is less than the screw rotor of corresponding position is wide Degree；When the shape of the relief hole is slot apertures, the width of relief hole is less than the crest top land of the screw rotor of corresponding position Width.
6. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: When the screw rotor rotates to a particular moment, which meets the following conditions: the crest top land of screw rotor will Whole relief holes are covered, and under the particular moment, after screw rotor continues to be rotated by 90 °, whole relief holes get rid of screw rod The masking of rotor crest top land.
7. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: The lead of screw of the screw rotor along pump housing air entry to exhaust outlet axis direction it is gradually smaller rule there are two types of, first For kind linearly to become smaller, second is that segmentation phase step type becomes smaller.
8. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: The relief valve is using automatic control vaccum stop valve or manually controls vaccum stop valve.
9. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, it is characterised in that: When gas pressure at the relief hole is higher than pressure at expulsion, relief valve is opened, the gas of overcompression pass sequentially through relief hole, Pressure-releasing chamber, relief tube and relief valve discharge, when the gas pressure at relief hole is no longer above pressure at expulsion, relief valve is closed It closes, pumps interior gas and be all discharged by the exhaust outlet of the pump housing.
10. a kind of vertical rotors for dry double-screw vacuum pump for having over-voltage degassing function according to claim 1, feature exist In: pressure sensor is installed at the air entry of the pump housing and passes through pressure when pressure sensor is located at pump housing air entry Sensor detects pump inlet pressure, and when pump inlet pressure is higher than critical pressure, relief valve is opened；Critical pressure is set as Pk, and Pk =Pout/R1/2~Pout/Rk/2, in formula, PoutTo pump pressure at expulsion, R is the compression ratio of screw vacuum pump, and k is the insulation system of gas Number；Or pressure sensor is installed at the relief hole of the pump housing and passes through pressure when pressure sensor is located at pump housing relief hole Sensor detects the gas pressure at relief hole, and when the gas pressure at relief hole is higher than pressure at expulsion, relief valve is opened.
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CN116538089A (en) * 2023-06-08 2023-08-04 北京通嘉宏瑞科技有限公司 Rotor structure and vacuum pump

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SU922317A1 (en) * 1980-05-07 1982-04-23 Предприятие П/Я А-3884 Rotor machine discharging apparatus
JPS6220687A (en) * 1985-07-17 1987-01-29 Kobe Steel Ltd Screw compressor
CN102395793A (en) * 2009-04-17 2012-03-28 厄利孔莱博尔德真空技术有限责任公司 Screw-type vacuum pump
CN203308712U (en) * 2013-06-07 2013-11-27 淄博瑞莱特真空设备有限公司 Variable-pitch double-thread screw vacuum pump
CN103883518A (en) * 2014-04-18 2014-06-25 湖南德尚源耐磨工业有限公司 Screw pump stator with pressure compensation cavity and screw pump

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU922317A1 (en) * 1980-05-07 1982-04-23 Предприятие П/Я А-3884 Rotor machine discharging apparatus
JPS6220687A (en) * 1985-07-17 1987-01-29 Kobe Steel Ltd Screw compressor
CN102395793A (en) * 2009-04-17 2012-03-28 厄利孔莱博尔德真空技术有限责任公司 Screw-type vacuum pump
CN203308712U (en) * 2013-06-07 2013-11-27 淄博瑞莱特真空设备有限公司 Variable-pitch double-thread screw vacuum pump
CN103883518A (en) * 2014-04-18 2014-06-25 湖南德尚源耐磨工业有限公司 Screw pump stator with pressure compensation cavity and screw pump

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