CN1740574A - Ejector capable of raising the cavitation performance of centrifugal pump - Google Patents
Ejector capable of raising the cavitation performance of centrifugal pump Download PDFInfo
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- CN1740574A CN1740574A CN 200510060436 CN200510060436A CN1740574A CN 1740574 A CN1740574 A CN 1740574A CN 200510060436 CN200510060436 CN 200510060436 CN 200510060436 A CN200510060436 A CN 200510060436A CN 1740574 A CN1740574 A CN 1740574A
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- centrifugal pump
- injection
- ejector
- ejecting
- cavitation performance
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Abstract
The ejector capable of raising the cavitation performance of centrifugal pump includes successively ejecting inlet, mixing section, diffusion section and ejecting outlet. There are annular cavity around the ejecting inlet, ejecting interface on the annular cavity, several axial inclined ejecting nozzles in axial angle of 10-45 deg distributed homogeneously on the side wall of the annular cavity. Or, the ejecting interface has axial straight ejecting nozzle connected with the ejecting direction coincided with the central axis of the ejector. For high speed centrifugal pump, combined structure of inducing wheel and ejector is adopted, and for common centrifugal pump, ejector is adopted directly in obtaining optimal cavitation performance. The centrifugal pump with ejector may be used in conveying acids, alkalis, salts, alcohols, medicine solution and other liquid medium containing solid particle in the temperature of -200 to +400 deg.c, especially those with strict cavitation performance requirement.
Description
Technical field
The present invention relates to fluid conveying machine, relate in particular to a kind of ejector that can improve cavitation performance of centrifugal pump.It is to adopt ejectors technique to improve the cavitation performance of centrifugal pump, is the combination of Jet injector and centrifugal pump.
Background technique
Cavitation damage is the major reason of centrifugal pump fault.In a single day cavitation damage takes place in centrifugal pump, not only causes pump performance not meet the demands, and produces and to find time and flutter failure, causes the pump cisco unity malfunction.Along with centrifugal pump to speed up development and carry the easily diversity of vaporization medium, the cavitation performance of pump has been proposed more and more higher requirement.
The cavitation performance that improves centrifugal pump has two approach, and the one, improve device net positive suction head NPSH
a, the 2nd, reduce pump necessary NPSH NPSH
rImproving the device net positive suction head mainly is to realize that by being added to mouth pressure or increasing the import setting height(from bottom) this brings suitable trouble in actual applications the installation of pump and the layout of pipeline.External once the employing increased the axial flow suction booster that is similar to preposition inducer before main centrifugal pump, this structure can improve the cavitation performance of main centrifugal pump to a certain extent, but it is limited improving cavitation performance by axial impeller on the one hand, this on the other hand method causes the pump structure complexity, having increased investment and operating cost, is not desirable way therefore.
Reduce pump necessary NPSH NPSH
rIt is the essential measure that improves mercury vapour erosion performance.The principal element that influences mercury vapour erosion surplus is the geometrical shape of pump impeller inlet part, as the impeller inlet diameter, and impeller inlet laying angle, the shape of entrance edge of blade, the number of blade, impeller inlet flow channel shape etc.In order to improve the cavitation performance of pump, adopt the optimal design of impeller, improve the cavitation performance that technology also can improve pump to a certain extent.But adopt rational blade wheel structure and shape to reduce NPSH
rBe very limited, the cavitation specific speed that designs good radial flow centrifugal impeller is 1800～2200.At present, the inducer technology is one of effective way that improves cavitation performance of centrifugal pump.Adopt the cavitation specific speed of the centrifugal pump of inducer design can reach 4000～5000.Satisfied the requirement of industrial field to a certain extent though before the centrifugal pump main impeller, increase preposition inducer to the pump anti-cavitation performance.But, if will obtain higher cavitation specific speed, be not enough then by the single inducer of design, can adopt the cascaded structure of first order Variable-pitch Inducers and second level taper uniform pitch inducer to make high speed centrifugation obtain superior cavitation performance.Though the two-stage inducer obtains the cavitation performance higher than single-stage inducer, its operating range is narrower than single-stage inducer, and makes axial length elongated, complex structure.Simultaneously the parameter of some centrifugal pump also is not suitable for making the high speed centrifugation pump structure, does not almost play effect to improving cavitation performance for the centrifugal pump design inducer of ordinary rotational speed.
Summary of the invention
The purpose of this invention is to provide a kind of ejector that can improve cavitation performance of centrifugal pump.
A kind of ejector that can improve cavitation performance of centrifugal pump is provided with injection import, mixing section, diffuser and injection outlet successively, be provided with annular chamber at injection import periphery, be provided with the injection interface on annular chamber, be provided with a plurality of equally distributed axial tiltedly driving nozzles at the annular chamber sidewall, axially tiltedly driving nozzle is 10 °～45 ° with axial angle.
The another kind of ejector that can improve cavitation performance of centrifugal pump is provided with injection import, mixing section, diffuser and injection outlet successively, sidewall in the injection import is provided with the injection interface, be connected to axially straight injection single nozzle on the injection interface, axially straight one-jet injection direction of injection and ejector central axes perpendicular to injection import sidewall.
The present invention draws the part high-energy fluid of pump discharge the injection interface of getting back to ejector by the injection loop between centrifugal pump outlet discharge pipe and the ejector injection interface; The high-octane jet flow that the injection interface draws back in ejector enters diffuser with low-energy workflow after the mixing section of ejector mixes, dynamic pressure can be converted into static energy, enters the import of centrifugal pump then; The pressure that has improved the pump intake place improves the cavitation performance of centrifugal pump.For high speed centrifugal pump, take the composite structure of inducer and ejector; For the centrifugal pump of ordinary rotational speed, directly adopt ejector to obtain best cavitation performance.Centrifugal pump with ejector can be used for the delivery temperature scope and contains the liquid medium of solid particle, particularly strict to cavitation performance easy vaporization liquid medium for-200～400 ℃ acids, bases, salt, alcohols, benzene class, alkanes, soup class and water class etc.
The ejectors technique of ejector is the combination of Jet injector and centrifugal pump, is similar to jet pump a little, and the former draws the sub-fraction high pressure liquid stream from the outlet of pump itself to enter into pump inlet, its objective is the net positive suction head that improves pump inlet; The latter then mainly is that other place introduces high pressure liquid stream as power source, its objective is the liquid that will carry in order to carry.The flow that draws back just is equivalent to utilize enlargement discharge increasing specific speed to design, can also suitably raise the efficiency low specific-speed centrifugal pump, therefore under the situation of Rational Parameters, adopting ejectors technique is very little to the influence of efficient, and is clearly to the raising of cavitation performance.
Description of drawings
Fig. 1 is equipped with centrifugal pump structure schematic representation of the present invention;
Fig. 2 is a kind of ejector structural representation that can improve cavitation performance of centrifugal pump;
Fig. 3 is the ejector structural representation that another kind can improve cavitation performance of centrifugal pump;
Among the figure: water tank 1, draw return pipe road 2, valve 3, pump discharge discharge pipe 4, centrifugal pump 5, ejector 6, inlet pipeline 7, injection import 8, injection interface 9, annular chamber 10, axially tiltedly driving nozzle 11, mixing section 12, diffuser 13, injection outlet 14, axially straight injection single nozzle 15.
Embodiment
As shown in Figure 1, be equipped with in the centrifugal pump of the present invention, the exit portion energized fluid of centrifugal pump 5, draw the ejector of getting back to before the pump inlet 6 from pump discharge discharge pipe 4 by the return pipe road 2 that draws on the injection loop, the front end of ejector 6 links to each other with water tank 1 by inlet pipeline 7, and the rear end links to each other with the import of pump.Drawing the size of capacity of reflux regulates by valve 3.Link to each other by bolt between the pump housing of ejector and centrifugal pump.
Before the present invention is installed in centrifugal pump 5 imports, by the injection loop between the injection interface 9 of centrifugal pump 5 outlet discharge pipes 4 and ejector 6 the part energized fluid of centrifugal pump outlet is drawn the injection interface 9 of getting back to ejector 6, the reflux that draws of injection interface 9 enters diffuser 13 through the working fluid that enters with injection import 8 behind the nozzle together after the mixing section 12 of ejector 6 mixes, enter the import of centrifugal pump 5 then, improve the pressure at pump intake place, thereby improved the cavitation performance of centrifugal pump.
As shown in Figure 2, a kind of ejector that can improve cavitation performance of centrifugal pump is provided with injection import 8, mixing section 12, diffuser 13 and injection outlet 14 successively, be provided with annular chamber 10 at injection import 8 peripheries, be provided with injection interface 9 on annular chamber 10, be provided with a plurality of equally distributed axial tiltedly driving nozzles 11 at annular chamber 10 sidewalls, axially tiltedly driving nozzle 11 is 10 °～45 ° with axial angle.
As shown in Figure 3, the another kind of ejector that can improve cavitation performance of centrifugal pump is provided with injection import 8, mixing section 12, diffuser 13 and injection outlet 14 successively, sidewall in injection import 8 is provided with injection interface 9, be connected to axially straight injection single nozzle 15 on the injection interface 9, the injection direction and the ejector central axes of axially straight injection single nozzle 15 perpendicular to injection import sidewall.
In practice of engineering design, the valve of energy accurate flow adjustment is installed on the pipeline in injection loop.For guaranteeing can mix equably between working fluid and the driving fluid through nozzle and enlarging, nozzle should should satisfy greater than the distance of mixing section and diffuser simultaneously to the distance L between inducer or the impeller:
In the formula: θ---the jet direction angle of nozzle;
D
t---the centrifugal pump inlet diameter.
L gets the efficiency factor that higher value will help improving mixing, but can increase the axial length of whole centrifugal pump.When design, should take all factors into consideration.
The formula of ejector jet efficiency factor ε as shown in the formula:
In the formula: NPSH
a---install given net positive suction head
NPSHa---the net positive suction head that inducer or impeller inlet leading edge can reach after injection mixes;
H---centrifugal lift of pump;
Q---real work flow;
Q
1---draw capacity of reflux, i.e. liquid stream flow of drawing from pump discharge
During work, working fluid enters the mixing section 12 of ejector from the import 8 of ejector 6, draw the mixing section 12 that capacity of reflux is introduced the high energy flow of pump discharge by injection interface 9, axially straight injection single nozzle 15 or annular chamber 10 and axially oblique driving nozzle 11 ejector, the speed of two strands of liquid streams reaches unanimity in the time of will arriving the mixing section end, mixes and finishes substantially.Mixed solution flows to into diffuser 13, and the flow velocity of mixed solution stream reduces gradually in diffuser 13, and pressure rises, and finishes from the conversion of kinetic energy to pressure energy.Liquid flows to the import into centrifugal pump then.Drawing the size of capacity of reflux regulates by valve 3.
The ejector that can improve cavitation performance of centrifugal pump of the present invention comprises following general design parameter:
Temperature T=-200～400 ℃
Ejector inlet diameter D
N=centrifugal pump inlet diameter D
t
Throat diameter D
k
Length of mixing
Diffuser length
Nozzle is to inducer or the preceding length of impeller
The diameter of nozzle: φ=2～5mm
Wherein:
Axially oblique injection multiinjector ejector
10 °≤the θ of angle at the jet direction angle of nozzle≤45 °
The number of nozzle: 4,6,8,12 or 16, along circumferentially evenly distributing.
Claims (3)
1 one kinds of ejectors that can improve cavitation performance of centrifugal pump, it is characterized in that: it is provided with injection import (8), mixing section (12), diffuser (13) and injection outlet (14) successively, be provided with annular chamber (10) at injection import (8) periphery, be provided with injection interface (9) on annular chamber (10), be provided with a plurality of equally distributed axial tiltedly driving nozzles (11) at annular chamber (10) sidewall, axially tiltedly driving nozzle (11) is 10 °～45 ° with axial angle.
2. a kind of ejector that can improve cavitation performance of centrifugal pump according to claim 1 is characterized in that described a plurality of equally distributed axially oblique driving nozzle (11) is 4,6,8,12 or 16.
3 one kinds of ejectors that can improve cavitation performance of centrifugal pump, it is characterized in that: it is provided with injection import (8), mixing section (12), diffuser (13) and injection outlet (14) successively, sidewall in injection import (8) is provided with injection interface (9), be connected to axially straight injection single nozzle (15) on the injection interface (9), the injection direction and the ejector central axes of axially straight injection single nozzle (15) perpendicular to injection import sidewall.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510060436 CN1740574A (en) | 2005-08-19 | 2005-08-19 | Ejector capable of raising the cavitation performance of centrifugal pump |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510060436 CN1740574A (en) | 2005-08-19 | 2005-08-19 | Ejector capable of raising the cavitation performance of centrifugal pump |
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| CN1740574A true CN1740574A (en) | 2006-03-01 |
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| CN 200510060436 Pending CN1740574A (en) | 2005-08-19 | 2005-08-19 | Ejector capable of raising the cavitation performance of centrifugal pump |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968064A (en) * | 2010-11-17 | 2011-02-09 | 重庆大学 | Anti-cavitation centrifugal pump |
| CN102207091A (en) * | 2011-06-07 | 2011-10-05 | 张意立 | High-concentration centrifugal pulp pump capable of spraying water on inner and outer corners |
| CN102635555A (en) * | 2011-02-14 | 2012-08-15 | 张意立 | High-concentration centrifugal pulp pump capable of spraying water at inner corner |
| CN103016396A (en) * | 2012-12-11 | 2013-04-03 | 江苏大学 | Centrifugal pump hydraulic design method controlling maximum flow by cavitation |
| CN104929988A (en) * | 2015-05-29 | 2015-09-23 | 上海东方泵业(集团)有限公司 | Cavitation eliminating method and device |
| CN105065341A (en) * | 2015-07-15 | 2015-11-18 | 西安交通大学 | Ejector of which mixing cavity is in parallel connection with bypasses |
| CN105090045A (en) * | 2014-12-02 | 2015-11-25 | 芜湖三峰节能设备有限公司 | Centrifugal pump with industrial mechanical seal |
| CN105090094A (en) * | 2014-12-02 | 2015-11-25 | 芜湖三峰节能设备有限公司 | Device for improving mechanical sealing of industrial centrifugal pump machine |
| CN105090044A (en) * | 2014-11-21 | 2015-11-25 | 衢州学院 | Centrifugal pump |
| CN105781955A (en) * | 2016-05-23 | 2016-07-20 | 肥西县鑫山机械厂 | Centrifugal pump with industrial mechanical seal |
| CN106837887A (en) * | 2017-03-14 | 2017-06-13 | 浙江理工大学 | The liquid ejection device of injection Parameter adjustable |
| CN108005908A (en) * | 2017-12-20 | 2018-05-08 | 江苏海事职业技术学院 | A kind of centrifugal pump of anti-cavitation |
| CN109630471A (en) * | 2018-11-20 | 2019-04-16 | 衢州学院 | A kind of induction apparatus of incidence angle variable degree and axial position |
-
2005
- 2005-08-19 CN CN 200510060436 patent/CN1740574A/en active Pending
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968064A (en) * | 2010-11-17 | 2011-02-09 | 重庆大学 | Anti-cavitation centrifugal pump |
| CN102635555A (en) * | 2011-02-14 | 2012-08-15 | 张意立 | High-concentration centrifugal pulp pump capable of spraying water at inner corner |
| CN102635555B (en) * | 2011-02-14 | 2014-11-12 | 广东凌霄泵业股份有限公司 | High-concentration centrifugal pulp pump capable of spraying water at inner corner |
| CN102207091A (en) * | 2011-06-07 | 2011-10-05 | 张意立 | High-concentration centrifugal pulp pump capable of spraying water on inner and outer corners |
| CN102207091B (en) * | 2011-06-07 | 2012-12-12 | 张意立 | High-concentration centrifugal pulp pump capable of spraying water on inner and outer corners |
| CN103016396A (en) * | 2012-12-11 | 2013-04-03 | 江苏大学 | Centrifugal pump hydraulic design method controlling maximum flow by cavitation |
| CN105090044B (en) * | 2014-11-21 | 2017-07-14 | 衢州学院 | Centrifugal pump |
| CN105090044A (en) * | 2014-11-21 | 2015-11-25 | 衢州学院 | Centrifugal pump |
| CN105090045A (en) * | 2014-12-02 | 2015-11-25 | 芜湖三峰节能设备有限公司 | Centrifugal pump with industrial mechanical seal |
| CN105090094A (en) * | 2014-12-02 | 2015-11-25 | 芜湖三峰节能设备有限公司 | Device for improving mechanical sealing of industrial centrifugal pump machine |
| CN104929988A (en) * | 2015-05-29 | 2015-09-23 | 上海东方泵业(集团)有限公司 | Cavitation eliminating method and device |
| CN105065341A (en) * | 2015-07-15 | 2015-11-18 | 西安交通大学 | Ejector of which mixing cavity is in parallel connection with bypasses |
| CN105781955A (en) * | 2016-05-23 | 2016-07-20 | 肥西县鑫山机械厂 | Centrifugal pump with industrial mechanical seal |
| CN106837887A (en) * | 2017-03-14 | 2017-06-13 | 浙江理工大学 | The liquid ejection device of injection Parameter adjustable |
| CN108005908A (en) * | 2017-12-20 | 2018-05-08 | 江苏海事职业技术学院 | A kind of centrifugal pump of anti-cavitation |
| CN109630471A (en) * | 2018-11-20 | 2019-04-16 | 衢州学院 | A kind of induction apparatus of incidence angle variable degree and axial position |
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