CN1022435C - Oppositely-arranged double-rotor centrifugal fluid-charger - Google Patents

Abstract

The present invention relates to a centrifugal fluid pressurizer with double oppositely arranged rotors. The centrifugal fluid pressurizer is provided with a large impeller and a small impeller, wherein the large impeller covers the small impeller and is symmetrical to the small impeller so as to perform the function of a rotary diffuser. The large impeller can effectively reduce the high speed of a fluid generated by the small impeller to about zero, or lead the fluid to move in an opposite direction, so that the friction loss of a shell body surrounding the large impeller is reduced, and integral efficiency is obviously increased. Therefore, the fluid pressurizer improves centrifugal turbo blowers, compressors or turbine pumps.

Description

Oppositely-arranged double-rotor centrifugal fluid-charger

The present invention relates to a kind ofly to changeing double rotor ionic formula fluid-charger, it is centrifugal mixed-flow, can increase the efficient of turbo blower, compressor or turbine pump.

In general, the centrifugal blower or the efficient of pump, be less than the efficient of the blower or the pump of axial flow, but when specific speed Ns hour, that is to say, when the big and power of required pressure hour, centrifugal blower or pump commonly used, in order to make clearly explanation, at first introduce turbo blower or turbocompressor.

People it is generally acknowledged that the efficient of common centrifugal turbo blower is inferior to axial flow, its reason be dynamic pressure that its Diffuser provides impeller when converting static pressure to efficient lower.

The inventor learns that from its experience for common centrifugal turbo-blower, the efficient of receded disk impeller itself is not low, can reach 90% or higher according to design.But, specific speed Ns hour, its total efficiency is generally 65-70%.When big the and power of specific speed Ns was big, its total efficiency can reach 85%, but still was inferior to the total efficiency (90-95%) of axial flow when high-power.

A kind of fluid-charger with rotary diffusing device is disclosed in No. the 4449888th, the U. S. Patent, the high-velocity fluid that comes out from its pump rotor 14 is guiding and first impeller rotary diffusing device in relative rotation directly, rely on the path that the rotary diffusing device expands gradually and relatively rotate, the absolute velocity in rotary diffusing device outlet port is descended, the dynamic pressure of high-velocity fluid is become static pressure, and reduce fluid through around the volute casing of rotary diffusing device or the frictional loss when having the suitable housing in a space, improve the efficient of pump and increase the pressure of fluid.But, thereby still await improving in the effect of circumferential components that reduces the diffuser exit liquid speed or outlet absolute velocity because its first impeller (pump rotor) and second impeller (rotary diffusing device) are homodromal.

The object of the present invention is to provide a kind of fluid-charger with rotary diffusing device, wherein first impeller and second impeller rotate along opposite direction respectively, significantly improve the circumferential components or the outlet absolute velocity of rotary diffusing device outlet port liquid speed, thereby further improved the efficient of fluid-charger.

For achieving the above object, the high-velocity fluid that comes out from its first impeller according to a kind of fluid-charger with rotary diffusing device of the present invention is directly or by a volute casing or have than the stationary diffuser of short-range missile to blade, fluid is suitably slowed down, guiding and first impeller, second impeller in relative rotation after the supercharging, rely on relatively rotating of the path that second impeller expands gradually and second impeller, the second impeller outlet place fluid absolute velocity is descended, the dynamic pressure of high-velocity fluid is become static pressure, and reduce fluid the flow through volute casing of second impeller or the frictional loss when having the housing in space and increase hydrodynamic pressure, it is characterized in that first blade and second blade rotate along opposite direction respectively.

The difference of getting clear between rotary diffusing device and the stationary diffuser is very important, it is said, the limit that stationary diffuser with guide vane effectively reduces liquid speed is, the speed ratio of diffuser exit place and diffuser intake is 1/3 to 1/4, for example, the speed of 240 meter per seconds is to reduce to 80 to 60 meter per seconds, and therefore, residual dynamic pressure is consumed by the friction in the housing.

When the reduction of speed ratio was very big, the size of the length of guide vane and Diffuser and housing all need be done greatlyyer, and this can make frictional loss increase, and decrease in efficiency is very unfavorable.

On the other hand, when using the rotary diffusing device, because diffuser vane forms the path of expansion gradually, also because the rotation of Diffuser, the two comprehensive effect make fluid can introduce than the much smaller absolute velocity of general expression housing around volute chamber or have housing than large space, in addition, the length of rotary diffusing device blade can be done shortlyer than stationary diffuser blade as shown in Figure 2, therefore, frictional loss in impeller and the housing is less, that is to say, owing to used the rotary diffusing device, at first can reach high static pressure liter very effectively, the present invention is described in existing contrast accompanying drawing down in detail.

Fig. 1 is the simple embodiment side view of structure of the present invention;

Fig. 2 is the front elevation of looking from Fig. 1 embodiment suction side;

Fig. 3 and Fig. 4 are respectively the velocity diagrams of first impeller inlet shown in Figure 1 and outlet;

Fig. 5 and Fig. 6 are respectively the velocity diagrams of second impeller inlet shown in Figure 1 and outlet;

Fig. 7 is the side view of one embodiment of the invention;

Fig. 8 is the schematic representation according to mixed flow blower of the present invention;

Fig. 9 is the side view that light shown in Figure 8 is put modification;

Figure 10 is the structural representation of used duplex bearing in the device shown in Figure 9;

Figure 11 is the sectional view of the present invention's one preferred embodiment.

The simplest reason of structure embodiment illustrated in fig. 1 is, first and second impellers all are directly installed on respectively on separately the motor shaft.

In this structure, because of opening the suction side, pipeline can not be coupled, and still, the blower of this suction side open mode there is no a lot of restrictions when using.

In Fig. 1, label 1 is the motor of first impeller, and 2 is first impeller shaft, and 3 is first impeller, and 4 for to be used to improve the guide plate of first impeller adiabatic efficiency, but in some cases, can save guide plate.5 is the volute chamber between first impeller 3 and second impeller 56, radial width is approximately the 10-20 millimeter, so that minimizing noise, make flowing evenly of fluid, promptly improve the efficient of second impeller, but volute chamber too greatly also can lower efficiency, 7 is second impeller motor, 8 is second impeller shaft, and 9 is volute chamber, still, design to such an extent that be in close proximity under zero the situation at the circumferential speed of the absolute velocity of the second impeller outlet place fluid, preferably adopt a kind of simple, large space housing, 10 is the protecgulum of housing 9, should open it when loading and unloading second impeller.

Though aspect the efficient of improving turbo blower ring compressor, very effective to second impeller that changes, it needs the high Sealing Device of some cost to reduce the leakage of high-pressure liquid, in other words, as shown in Figure 1, the lid of second impeller 6 is divided into small one and large one two circular portions

The diameter of its circular boundary is a bit larger tham the external diameter of first impeller, and smaller portions 11 freely are loaded and unloaded on major part, except that smaller portions 11, also is provided with a band labyrinth sealed trip ring 12.Make very thin, very light, the balance as far as possible of smaller portions 11, this point is very important, so that prevent to destroy dynamic balancing when loading and unloading major part.Make the trip ring 12 and the gap between the second impeller opening ring 13 of first impeller enough little so that keep the validity of Sealing Device.This point is also very important.If necessary, the inboard that is preferably in trip ring 13 is provided with the labyrinth sealing circle.The outside of trip ring 13 is by 14 sealings of labyrinth sealing circle.Labyrinth sealing circle 14 is supported on protecgulum 10 so that reduce the leakage of high-pressure liquid at the second impeller outlet place.Be provided with equalizing piston 15 at the first impeller rear side.It is encased by the equalizing piston 16 of second impeller.Gap between two equalizing pistons 15,16 is by 17 sealings of labyrinth sealing circle.

In addition, the periphery of equalizing piston 16 is sealed by the labyrinth sealing circle 18 that housing 8 is supported.Fig. 2 represents the preferred embodiment of the used impeller of the present invention.First impeller has radial blade and guide plate so that make the fluid at the first very little impeller outlet place of external diameter have big absolute velocity.Because common stationary diffuser is difficult to big absolute velocity like this is transformed into static pressure effectively, so the most handy impeller that has recurvate blade replaces radial, still, as mentioned above, for little specific speed Ns, efficient is still very low.

Yet according to the present invention, above-mentioned big absolute velocity is that second impeller is transformed into static pressure very effectively by the rotary diffusing device.Therefore, shown in Fig. 3,4,5 and 6, make that the liquid speed at the second impeller outlet place is very little.The result makes the frictional loss in the housing very little.In addition, because second wheel speed is low, only be 1/2 to 1/10 of first wheel speed, so because the wheel friction loss that second wheel rotation causes is little.

Fig. 3 is the velocity diagram at the first impeller inlet place, and wherein, U1 is the circumferential speed of guide plate 4 at the average diameter D1 place of its inlet edge, and cm1 is the axis plane velocity (meridian velocity) of this inlet's fluid, and W1 is the relative velocity of fluid to blade.Here D1 is less, and U1 is very little, and cm1 is less at first, and W1 is also less, so in this inlet, the disturbance and the frictional loss of fluid are little.This is one of benefit of bringing of guide plate 4.

Fig. 4 is the velocity diagram at the first impeller outlet place, and wherein, U2 is a circumferential speed, and cm2 is an axis plane velocity, and W2 is the relative velocity that equals cm2.

In order to do clearer explanation, can suppose, a lot of and the fluid of first impeller blade is accurately with Radial Flow, so, the absolute velocity of the fluid that sends at the first impeller outlet place then is C2, and as shown in Figure 4 greater than U2, but the frictional loss in first impeller is very little, because length of blade is little, W2 is also little for relative velocity.We can say that the pressure loss in the radial blade formula impeller is very little, its efficient is very high.Yet the absolute velocity C2 of outlet port fluid is big, thereby the efficient of this Diffuser becomes an open question.

Fig. 5 is the velocity diagram at the second impeller inlet place, wherein, U3 be second impeller at inlet's circumferential speed, U2 be depend on design condition suitably selected.Between 1/2 to 1/10 of the circumferential speed at the first impeller outlet place, Cu3 is the circumferential component velocity of fluid that flows into second impeller.Cu2 is called the circumferential component velocity of above-mentioned speed C2, and Cu3 is calculated as follows:

Cu3＝ (D2)/(D3) ·Cu2＝ (D2)/(D3) ·U2

In the formula, D2 is the external diameter of first impeller, and D3 is the internal diameter of second impeller, and when increase of volute chamber 5 diameters and D3 increase, then Cu2 then significantly reduces to Cu3, and produces the bigger increase of static pressure corresponding to the dynamic pressure difference.

The suitable size of volute chamber 5 provides good efficiency, and this reduces the frictional loss in second impeller effectively, also reduces the noise and the disturbance at the second impeller inlet place, and these all are certain, and still, volute chamber too greatly also can reduce efficient, and this also is certain.

But when required voltage rise height, thereby the relative velocity between first impeller and second impeller is when surpassing velocity of sound, and the Diffuser of short blade can reduce to relative velocity below the velocity of sound effectively by being equipped with very on the first impeller periphery.

Fig. 6 is the velocity diagram at the second impeller outlet place, and wherein, because the diffusion effect of the passage expanded gradually of second impeller, relative velocity W4 reduces half of W3 among Fig. 5, and the circumferential speed of fluid descends a lot so that changed direction.Make the above-mentioned circumferential speed Cu4 that has turned to keep that suitably less value is so that reduce around the frictional loss in the housing 9 of second impeller, this is very important.When the value of Cu4 be designed to reduce near or equal zero and its direction depends on the variation of flow velocity and when changing, preferably use the simple housing with large space to replace volute casing.Certainly when the design efficient blower, the most important thing is to make the rotating speed of first impeller high as far as possible, thereby make the external diameter of the external diameter of first impeller and second impeller as much as possible little, the Rational structure that is suitable for the rotor of high speed design is that its two ends are all supported, this is should do very for a short time because will make it reach the splendid every end diameter of axle of dynamic stability, thereby make the frictional loss of each bearing very little, and Fig. 7 just represents to realize an example of this purpose.As shown in Figure 7, the fore bearing of first impeller coaxially is contained in the suction port, and its rear bearing is on a position behind second impeller shaft, and second impeller shaft is made hollow so that the rear axle of first impeller of packing into therein.In fact, in order to obtain very high voltage rise, the rotating speed of second impeller can be up to the rotating speed of first impeller, owing to commentaries on classics absolute velocity is descended, even in this case also than the efficient height of common stage type pressurized machine.

In Fig. 7, the part identical with Fig. 1 uses identical label.As shown in Figure 7, the lubricant oil of the fore bearing 22 of first impeller is sent into by rib 19 and is discharged by rib 20.In addition, mix with fluid, be provided with mechanical sealing and/or wiper seal 21 in order to prevent lubricant oil.The fore bearing of second impeller is installed in the bearing housing that is fixed on the housing 9, and Bearing Installation is in bearing housing 23 thereafter, and bearing housing 23 is fixed on the flanged fitting that links to each other with the above-mentioned bearing housing of housing 9, and the rear bearing of first impeller is supported on bearing housing 24.Bearing housing 24 is connected on the flanged fitting that links to each other with bearing housing 23.The above-mentioned layout of bearing housing can suitably change.First impeller can or directly link to each other with a high speed driver by a gear or a belt drives.

Even design shown in Figure 7 needs the high lubricated and sealing system of cost, but realizes being suitable so that obtain high efficiency at a high speed.In addition, this makes the structure of suction side very simple.As shown in Figure 7, the guide plate at the first impeller inlet place is made with first impeller and is become one, but the branch body structure of its effect and Fig. 1 is identical, and second impeller uses sealed ball bearing, but bearing and lubricated selection all are freely.

Fig. 7 is the side view of an example, and first impeller shaft that wherein stretches to the back penetrates the hollow shaft of second impeller, supported by a bearing that is positioned at behind the described hollow shaft.

Fig. 8 is a mixed flow blower of the present invention, and it also is a kind of centrifugal blower.Simple in structure and avoid the lubricant oil fluid that bleeds for the Sealing Device that makes the first impeller front axle, make the first impeller fore bearing be contained in the outside of suction side and make its rear bearing be contained in (second impeller shaft makes hollow shaft so that the rear axle 2 of first impeller of packing into therein) behind second impeller shaft, this situation is seen Fig. 8.In this case, the length of first impeller shaft is quite big, and its external diameter is also quite big so that obtain enough dynamic stabilities, thereby the diameter of the second impeller shaft front end also becomes very big, this will increase the frictional loss of bearing, but because the rotating speed of second impeller is low, very little to the influence of total efficiency.Mixed-flow impeller is housed in Fig. 8, as long as it is enough little that the gap between guard shield 26 and the impeller keeps, it just is suitable for the bigger situation of Ns, so that obtain high efficient, the structure of this impeller is also very simple in addition, in Fig. 8, transmission device is selected the overdrive gear of first impeller and the belt of second impeller for use, but selecting for use of transmission device is freely, for example, can select single motor or Dual-motors Driving for use.

Power generally customizes greater than the motor of 55KW, and its unit price improves with the power increasing, therefore, the price of two low-power machines will be lower than the price of a heavy-duty motor, in addition, inrush current is also much smaller, because two motors are delayed startup individually, for example, two 55KW motors, cheap more about 30% than a 110KW motor, and inrush current also can reduce about 50%.

Fig. 9 is the side view of malformation shown in Figure 8, in Fig. 9, the fore bearing of first impeller is contained in the outside of inlet box as Fig. 8, its rear bearing is contained in the front end of second impeller shaft, so that make first impeller shaft short and make the diameter of second impeller shaft big not resembling among Fig. 8.

In above-mentioned layout, it is comparatively complicated that the lubrication system of second impeller bearing becomes, but the length of first impeller shaft can be done shortlyer, and its critical speed of rotation increases greatly, in addition, and the also danger that does not exist fluid to mix with lubricant oil.This bearing can be called an inner bearing (in-shaft-bearing) promptly with second impeller fore bearing duplex bearing together.The lubrication system of this bearing is shown in Fig. 9, and its details is shown in Figure 10.Figure 10 is the sectional view of lubrication system details shown in Figure 9.

In Fig. 9, two bearings of second impeller shaft are supported on bearing housing 23 and 27, these two bearing housings are connected to each other by flanged fitting, and the lubricant oil of axle inner bearing 31 is carried from the opening of lubrication box 28, and by slotted hole 30 inputs coaxial with second impeller shaft 8, discharge by the many holes on axle inner bearing 31 edges, and then introduce the fore bearing of second impeller and be discharged from.The 32nd, the seal oil in the lubrication box.It can be a mechanical sealing, spiral seal or other sealing.

Figure 10 has represented above-mentioned duplex bearing in detail, and thrust bearing and lubricant oil drain passageway have wherein drawn.In Figure 10.33 is thrust rings, and it is fixed in first impeller shaft by the helical thread portion 35 that is close in axle journal 34, and the thrust of bearing first impeller by thrust bearing 36 is to keep the tram of first impeller.The lubricant oil that had lubricated an axle inner bearing 31, thrust ring 33 and thrust bearing 36 is dished out outside the sharp edge of thrust ring 33 and is collected in the groove 38 that forms in second impeller boss, and by opening the fore bearing 40 of introducing second impeller in many holes 39 at the place, angle of groove 38.Need consider the pressure balance problem that the leakage by the gap between equalizing piston 15 and the labyrinth packing circle 17 causes about the seal oil of bearing 40.Above-mentioned leakage is led to ambient atmosphere by the many holes 41 on equalizing piston 16 edges, but, in equalizing piston 15 and 16, still retain certain pressure, it can make the fluid of leakage enter the seal oil circle that forms around thrust ring 33 column parts, in order to prevent the lubricant pollution fluid, have two sharp-pointed ring limits in the end of thrust ring 33, do not contain the fluid of lubricant oil, by flowing into the groove 44 of case 23 front sides formation around the hole of leaving as many holes 39 of oil passage 43 and discharging from exporting 45.Groove 44 is made up of promptly three parts, and the sleeve 46 from equalizing piston 16 stretches out is contained on the case 23, be provided with to prevent that lubricant oil from sneaking into the sealing cover 47 in the fluid that spills, and case 23.

On the other hand, the lubricant oil that had lubricated bearing 40 is collected the groove 48 of cartonning 23 opposite sides and discharges from the outlet 49 of bottom.

Because axle inner bearing 31 and axle journal 34 backward rotation, make relative velocity between bearing 31 and the axle journal 34 greater than the circumferential speed of axle journal 34 itself.In this case, for the heat of the frictional loss and the generation that prevent to increase bearing, make the bearing play only strengthen one to name a person for a particular job be effective according to the increase of relative velocity.It should be noted that the dynamic stability that makes bearing is not subjected to the influence that the gap increases and changes.The axle inner bearing is suitable for the very high-revolving situation of requirement first impeller, because it can reduce the length of first impeller shaft and increase dynamic stability.

Figure 11 is the sectional view of a recommended structure, and this structure is simplified on the whole.In Figure 11, the axle of first impeller 3 is cantilevered axle, and this penetrates the hollow shaft of second impeller 6, and its front is by axle inner bearing supporting, and its back is by being fixed in a locational bearing supporting behind the hollow shaft.In Figure 11, the label of removing other part outside 22a, 40a, 44a, 47a four parts is with noted earlier identical.The flow of lubricant that had lubricated axle inner bearing 31 is to be formed by the carriage 23a and the hollow cap 47a that keep cod 31 to groove 44a(groove 44a).Discharge by opening 45 then.In this case, lubricant oil does not flow into the fore bearing of second impeller.Be provided with two openings, upper shed 45 and under shed 45, wherein upper shed 45 is to discharge the liquid of leakage, under shed 45 is removal of lubricants.The lubricant oil of first impeller is to provide by the import 29 of opening on the first impeller after the bearing box 24, half oil flows to the front by the gap between the second impeller hollow axle and first impeller shaft, so that further flow into axle inner bearing 31, and second half oil flows to the back with the lubricated bearing that remains in the case 24, and two-part lubricant oil is discharged respectively then.

In the rear end of first impeller shaft 2, a cover shaft coupling is driven by suitable speeder 1a, but also can use a belt pulley or a small gear directly to replace described shaft coupling to increase the rotating speed of first impeller shaft 2, still, and in this case.Preferably use two motors of 180 ° of symmetric arrangement to drive, so that the complete equilibrium lateral force.Second impeller drives with belt pulley 25, but also available small gear replaces.And in Fig. 1, first impeller does not have side cover, but has only a trip ring, and this trip ring helps to strengthen inlet vane so that opposing centrifugal force also can play the labyrinth sealed effect, so that reduce escape of liquid.

Yet second impeller, 6 peripheries and without volute casing, used is a kind of cylindrical housings.

Owing to adopted said structure, the total efficiency of the compressor of blower of the present invention can bring up to 85～90%, and the total efficiency of common blower and compressor has only 65～75%.The present invention can save 20～30% power consumption.Therefore, owing to save electric power, will in 1 year, be compensated because of adopting the price that the commentaries on classics dual-rotor structure is increased.For example, the 300KW high pressure turbine blower that aerating wastewater uses, annual 360 Working days, 20 yen of every kilowatt-hour of expenses, so Mei Nian electricity expense then is 300 * 20 * 24 * 360=51,840,000 yen, suppose 20% of the above-mentioned expense of saving, savable expense can reach annual 10,000,000 yen, however the increase of blower cost is but less than 1/4 of institute's cost saving.

Therefore, the amortization period only is a some months, moreover, considers that it equally also is rational changing ordinary blower with the so high new blower of efficient.And multistage turbine blower that directly connects motor.Because rotating speed is low, the fluid distance is repeatedly turned round the loss of pressure head that causes, and its efficient is less than 65%, thereby is that 85% above-mentioned new blower replacing multistage turbine blower will be reduced expenses and be reached 30% with efficient.This is the very significant superiority of the present invention.And therefore this new-type blower floor space can change lower-powered ordinary blower with the bigger this new-type blower of power less than ordinary blower.

In the above description, mainly be to describe the present invention at blower or compressor, but the present invention is not limited to this two kinds of applications, and it also can be used for turbine pump, the turbine pump structure is similar to above-mentioned blower or compressor, but different on Sealing Device.The same with the situation of above-mentioned blower or compressor, when being used for turbine pump, the present invention also can raise the efficiency greatly.

Claims (8)

1, a kind of fluid-charger with rotary diffusing device, wherein, the high-velocity fluid that comes out from first impeller is directly or by a volute chamber or have than the stationary diffuser of short-range missile to blade, speed is suitably descended, and after increasing, hydrodynamic pressure is directed to and first impeller, second impeller in relative rotation, rely on relatively rotating of the path that second impeller expands gradually and second impeller, make the big fluid relative velocity of second impeller inlet place generation and the absolute velocity of the second impeller outlet place fluid is descended, the dynamic pressure of high-velocity fluid is transformed into static pressure, and by fluid is introduced one around the volute chamber of second impeller or suitable housing with a space reduce fluid in housing frictional loss and increase the pressure of fluid, it is characterized in that: described first impeller and second impeller rotate along opposite direction respectively.

2, according to the described fluid-charger of claim 1, it is characterized in that: described first impeller and second impeller are respectively by independent impeller-driven.

3, according to the described fluid-charger of claim 1, it is characterized in that: second impeller shaft is a hollow shaft, the end of stretching to first impeller shaft of the first impeller front is supported by a bearing, and an envelope has an oil passage by the inner outstanding rib supporting of suction port.

4, according to the described fluid-charger of claim 3, it is characterized in that: also have fluid-encapsulated path.

5, according to the described fluid-charger of claim 1, it is characterized in that: the front end of second impeller shaft is made hollow shape, one bearing wherein is housed, this bearing supports the rear end of first impeller, the lubricant oil of this bearing is provided with another bearing of first impeller by the slotted hole conveying coaxial with second impeller in the outside that sucks housing.

6, according to the described fluid-charger of claim 1, it is characterized in that: second impeller shaft is a hollow shaft, first impeller shaft coaxially is installed in it, first impeller shaft is a cantilevered axle, the front of first impeller shaft is by the bearing supporting that is contained in the second impeller hollow axle, its back is supported by a bearing that is positioned at described hollow shaft back, the lubricant oil of first impeller shaft is carried at the opening between the after the bearing box of the second impeller shaft after the bearing box and first impeller, end by described hollow shaft and the gap between first impeller are guided the described bearing that is contained in the described hollow shaft into and are guided the described rear bearing of first impeller into opposite direction, are appropriately discharged then.

7, according to the described fluid-charger of claim 1, it is characterized in that: second impeller shaft is a hollow shaft, first impeller shaft that stretches to the suction side is by being fixed on the bearing supporting that sucks hull outside, the rear axle that stretches to opposite side of first impeller pierces into the second impeller hollow axle, by the bearing supporting that is positioned at described hollow shaft back.

8, according to the described fluid-charger of claim 1, it is characterized in that: the protecgulum of second impeller is divided into small one and large one two circular portions, the diameter of its circular boundary is a bit larger tham the external diameter of first impeller, smaller portions are anchored on major part, also can on major part, freely unload, and smaller portions are equipped with the trip ring of a band labyrinth collar.

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