Ejector pump having turbulence reducing flow directing profiles

An ejector pump for the transport of materials or mixtures of materials capable of flowing with the aid of a fluid driving medium is provided. The ejector pump includes at least one flow management profile which is placed in the flow channel of the ejector pump and which displaces the fluid that is flowing against the profile in a lateral direction component away from the original direction of flow. Therefore, the fluid in the middle of the flow channel makes its way closer to one of the flow channel walls thus limiting the areas of turbulence that occur during the mixing of material that is to be transported with the driving medium.

The invention pertains to an ejector pump in accordance with the 
introductory clause of claim 1, in particular, a multistage injector pump. 
Injector pumps of this type have been known for a long time, from FR-A1-2 
577 284, for example, and are used both for the production of a vacuum as 
well as for the transporting of materials or mixtures of materials that 
are capable of flowing. To achieve a high efficiency, particular when 
there are large volumes to be pumped, a multistage form of implementation 
of the injection pump is known, in which the pump stages lie one after the 
other in the flow channel. This has the advantage, among others, that the 
flow energy of the driving medium, which can be either gaseous or liquid, 
is used until the velocity of flow has fallen below a level which no 
longer has an economically useful value in terms of structural effort. 
With ejector pumps, in particular those of the multistage design, there 
exists the problem that during the mixing of the driving medium with the 
material that is to be transported, areas of turbulence occur that reduce 
the efficiency of the pumping capability, particularly in the subsequent 
pumping stages and in their associated mixing zones. In order to solve 
this problem, it is known that in order to counter the effects of the 
turbulence, the overall length of the flow channel in the region of the 
mixing zone and the diffuser is extended to the extent that each of the 
areas of turbulence can subside to a level that is tolerable. In this 
regard, the length of the zone that acts on the flow in a smoothing 
fashion is proportional to the cross-sectional area of the flow channel in 
the area in which the flow is disturbed. However, the large overall 
lengths themselves represent a significant added expense in terms of 
construction. 
While in the case of ejector pumps in which the flow channel is circular in 
cross-section and in which the pass-through slot for the medium that is to 
be transported lies on a circumferential line of the flow channel 
cross-sectional area, as is the case with FR-A1-2 577 284, the residual 
energy of the driving medium can be kept relatively small, primarily in 
the case of ejector pumps with a rectangular cross-section that is 
relatively flat in comparison with its width, as is the case with the 
so-called flat-channel ejector pumps, the additional problem arises that 
the utilization of the residual energy of the driving medium is especially 
difficult, and is relatively unsatisfactory even with great structural 
efforts. Flat-channel ejector pumps of that type are known from EP-A-0 297 
550. 
In order to increase the suction power of an ejector pump with circular jet 
nozzles that are placed axially one after the other, in DE-A1-4 011 218 an 
annular implementation of such jets is introduced. This is achieved by 
means of an arbor that passes through the jets concentrically in the axial 
direction and that is uninterrupted through the entire length of the 
channel. Taking into account the rotational symmetry, this corresponds to 
a narrowing of the flow channel in the case of flat-channel ejector pumps, 
so that their flow channel is given, in comparison with the width, a 
flatter cross-section. In the case of generic ejector pumps, a decisive 
improvement in the suction power cannot be achieved by means of these 
measures, particularly in the case of flat-channel ejection pumps. 
Starting from that point, the invention performs the task of achieving more 
favorable flow characteristics in the flow channel for generic ejector 
pumps. 
This task is performed by means of an ejector pump with the characterizing 
features of the claims. 
By means of the profiles and/or dividing walls that are provided in 
accordance with the invention, areas of turbulence that occur during the 
mixing of the material that is to be transported with the driving medium 
can be kept relatively small. As a result, it becomes possible to keep the 
flow channel length, and thus the overall length of the pump, relatively 
small. In the case of multistage ejector pumps, as a result of the 
reduction of the areas of turbulence, their harmful effects on the 
subsequent pumping stages is reduced as well, and in particular, on the 
subsequent mixing zones in the flow channel. On the other hand, with the 
flow management profiles in accordance with the invention it is also 
possible to improve the effectiveness of the driving medium; in 
particular, the residual energy of the driving medium can be reduced with 
relatively little effort, and the pumping efficiency thus increased. The 
profiles and/or dividing walls in accordance with the invention have a 
particularly advantageous effect on those ejector pumps, in particular, 
multistage ejector pumps, in which the flow channel cross-section is 
comparatively flat and wide, as is especially the case with the so-called 
flat-channel ejector pumps, and even more specifically, those in which the 
cross-sectional areas are curved, in particular, lie on a circular area as 
is the case with DE-A1-34 20 652. 
It is now possible, in a number of different ways, to shape the profiles 
and/or dividing walls in accordance with the invention and to place them 
in the flow channel; in particular, it is possible to make use of 
variously shaped and variously placed profiles and/or dividing walls in 
one and the same channel, as is explained by way of example in the 
implementation examples. 
In the case of a first form of implementation of the profiles in accordance 
with the invention, they are configured as an elongated profile that has a 
cross-section which preferably has a shape that is similar to that of an 
airfoil. This profile is placed within the flow channel in such a way that 
its direction of longitudinal extension runs approximately perpendicular 
to the direction in which the flow channel runs, and thus runs 
approximately perpendicular to the primary direction of flow of the fluid 
(driving medium and the material that is to be transported) in the flow 
channel. A flow management profile of such a type of necessity has a 
certain volume, and displaces the fluid that is flowing against the 
profile and guides it with a lateral direction component away from its 
original direction of flow, so that the fluid in the middle--depending in 
part on its inertia--makes its way closer to the wall of the flow channel 
and thus brings about at the pass-through slot of the subsequent suction 
stage a higher fluid velocity of flow. A contraction of the cross-section 
in comparison with a flow channel without a flow management profile of 
such a type is as a rule avoided in this way. 
A profile of such a type makes it possible to construct flat-channel 
ejector pumps with improved efficiency which can be manufactured in a 
particularly economical manner, namely in an extrusion or continuous 
casting process (see form of implementation in accordance with FIG. 1). 
Profiles of such a type can also be used advantageously, however, in 
flat-channel ejector pumps that exhibit an annular flow channel which is 
directed radially towards the outside and which is known from, for one, 
DE-A1-34 20 652 for a single-stage ejector pump, and from the German 
registered utility model (registered utility model application G 92 10 
496) for multistage ejector pumps (see forms of implementation in 
accordance with FIG. 3 and FIG. 6). 
With profiles of such a type, a number of particularly advantageous 
measures can be taken. Thus, the flow management profiles in accordance 
with the invention can exhibit a symmetrical and/or airfoil-like profile 
and can be integrated into flat-channel ejector pumps that are constructed 
symmetrically with respect to the longitudinal center plane of the flow 
channel, that is, they are equipped on both sides of the flat channel with 
suction chambers and pass-through slots for the fluid to be transported 
that lie opposite each other, as is for example the case with the 
implementation example in accordance with FIGS. 1 and 2. 
The positioning of the profile has proven to be especially advantageous. 
In the case of multistage ejector pumps, it is to be recommended that the 
profile cross-sections of the profiles or dividing walls that are arranged 
one after the other in the direction of flow be increasingly enlarged in 
size. 
It is suggested as being particularly effective, that flow management 
profiles that are hollow inside be provided, and that the hollow space be 
joined with the flow channel on the one side and on the other, with the 
inlet for the material that is to be transported. As a result of this, the 
profile or dividing walls works entirely or additionally as a suction 
chamber. 
The dividing wall in accordance with the invention (placed along side), is 
configured as an elongated dividing wall which is approximately parallel 
to the flow and which divides the flow channel cross-section into 
approximately parallel partial flow channels. This measure can also be 
realized both in the case of cross-sectional areas that are straight as 
well as in the case of cross-sectional areas that are circular (see FIGS. 
2 and 3). It has been shown that flow management profiles of such a type 
significantly reduce the areas of turbulence in the mixing zone. This has 
an especially beneficial effect primarily in the case of multistage 
ejector pumps, in particular, those of the flat-channel type. 
For the further improvement of the flow conditions--by means of the 
reduction of the cross-sections of the inlets as well--in flat-channel 
injector pumps, it can be advantageous to configure and/or to place the 
dividing walls in such a way that the flow channels run from one another 
in the direction of flow in an approximately conical manner. This can be 
realized in a simple way in accordance with claim 8 by virtue of the fact 
that the dividing walls taper in the direction in which the flow channels 
run. 
An ejector pump in accordance with the invention can be manufactured in an 
especially cost-effective way if it is built up from individual ejector 
pump modules in accordance with claim 9. It is also possible as a result 
of the modular design, for ejector pumps of different capacities to be 
produced through the joining together of a varying number of ejector pump 
modules, without new tools being necessary for this purpose. The ejector 
pump modules can be designed in such a way that they are suitable for the 
building up of flat-channel injection pumps (see implementation form in 
accordance with FIG. 4), or in such a way that by means of the joining 
together of several ejector pump modules to each other, a radial ejector 
pump is created that forms a segment of a circle or that extends over a 
full circle (see form of implementation in accordance with FIG. 5). 
The components which are named above and which are claimed and described in 
the implementation examples and which are to be used in accordance with 
the invention, are not subject to any special exception conditions with 
respect to their size, shape, choice of material, and engineering design, 
so that the selection criteria that are known in the area of application 
under discussion can be applied with no restrictions.

The ejector pump 100 shown in FIG. 1 consists of a housing 5 made up of two 
identical housing parts 5A and 5B, which are identical, produced of metal 
by means of the extrusion process, arranged mirror-symmetrically to each 
other, and joined to each other. This housing includes a flow channel 17, 
which runs perpendicular to the plane of the drawing, is flat in 
cross-section, is straight, and expands conically from its inlet side for 
the driving medium at jet 18 to the outlet 22. By means of an entry 
chamber 6, and it in turn by means of an inlet 15, the slot-like jet 18 is 
impinged upon by a fluid driving medium which can be liquid, gaseous, or 
vaporous. 
In the flow channel walls 17A and 17B, which are placed so they lie 
opposite each other and run conically from one another, there are found 
pass-through slots 21, which run perpendicular to the plane of the 
drawing, that is, parallel to the jet 18 (flat jet), for the medium to be 
transported, which is a material that can flow or a mixture of materials 
that can flow (liquid, gaseous, or vaporous). In order to impinge upon the 
pass-through slots with the fluid that is to be transported, suction 
chambers 7 through 10, which run parallel to the pass-through slots 21 
inside the housing parts 5A and 5B, are fluidically connected on the one 
side with the flow channel by means of the pass-through slots 21, and on 
the other side, with the chamber that holds the fluid that is to be 
transported by means of inlets 16 that are at the front end. In accordance 
with FIG. 1, end walls 26 are therefore placed at the front. 
The driving medium, which comes through the jet 18 (jet slot) into the flow 
channel 17 at a high velocity, creates in the suction chambers 7 through 
10 a negative pressure by means of which the medium to be transported is 
sucked into the flow channel 17 and there mixes with the driving medium 
and flows along with it towards the outlet 22 of the flow channel 17. The 
inlets 16 or the passthrough slots 21 can be provided with check valves in 
the way in which they are generally familiar for multistage ejector pumps 
(see FR-A1-2 577 234), and which therefore do not require a more detailed 
explanation. 
In the flow channel 17, there is adjoining (in the direction of flow) each 
of the opposing pass-through slots 22 of each pumping stage a mixing zone 
19, and adjoining that, a diffuser (diffusion zone) 20. The mixing zone 
and the diffuser zone can overlap each other at least in part. 
At the level of the pass-through slots of the second through fourth pumping 
stages, to which the suction chambers 8 through 10 belong, three 
mirror-symmetrical, elongated profiles 1 through 3, which are 
airfoil-shaped in cross-section, run perpendicular to the direction in 
which the flow channel runs (and thus perpendicular to the plane of the 
drawing) and exactly in the longitudinal center plane 17C of the flow 
channel 17. The cross-section of these three profiles, which act as flow 
management profiles, increases from profile to profile, viewed in the 
direction of flow. The round, head ends of the profiles act as the leading 
edge (as with an airfoil), while the pointed tail ends point in the 
direction of flow. 
As a result of the volumes displaced by the profiles 1 through 3, a partial 
change in the direction of the approaching fluid is caused away from the 
primary direction of flow on both sides of the longitudinal center plane 
17C within the flow channel 17 (see flow arrow in FIG. 1). 
Each of the profiles 1 through 3 is found--seen in the direction of 
flow--at the same level as the pass-through slots 21 of the associated 
pumping stage, that is, the associated suction chamber 8 or 9 or 10. In 
conjunction with this, the location of the narrowest cross-section is 
located immediately upstream of the pass-through slot. 
At profile 3, a special form of implementation of the invention is 
explained by way of example: Profile 3 is a profile which is hollow 
inside, the hollow space 23 of which functions as a suction chamber, and 
which is fluidically connected on the one side--by means of sidewall 
openings 24--with the flow channel 17, and on the other side--at the faces 
(end walls 26) by means of an inlet 16--with the space containing the 
fluid that is to be transported. In an extreme case, it is also possible, 
and to be considered as lying within the framework of the invention, to 
house the suction chambers only in the flow management profiles, in the 
way in which this was explained with the aid of the profile 3. In the same 
way, it is also conceivable to house the suction chambers in the flow 
channel walls 17A and/or 17B in part of the pumping stages, and in one or 
more other suction stages, to house the suction chamber, of which there is 
at least one, in the associated flow management profile, of which there is 
at least one. In the same way, it is also conceivable to arrange the flow 
management profiles not only one after the other in the direction of flow, 
but instead of this or as a supplement to this, to arrange them along side 
each other as well, and to allow the flow to pass, in the direction of the 
outlet end of the flow channel, between the profiles that have been placed 
along side each other. 
The profiles 1 through 3 which serve as flow management profiles can be 
fastened inside the ejector pump 100 in the most widely varying ways. 
Proving to be especially advantageous for this purpose are elongated 
dividing walls 4, which also serve as flow management profiles (FIG. 2) 
and which in their longitudinal direction run approximately parallel to 
the direction in which the flow channel runs, and which thus run 
approximately parallel to the primary direction of flow of the fluid in 
the flow channel and subdivide the flow channel cross-section into partial 
flow channels 17', 17", 17'", . . . , as is indicated in FIG. 2. It is 
possible --possibly in addition--to use for fastening the profiles 1 
through 3 the dividing walls 4', which taper in the direction of flow. As 
a result of these measures, the side surfaces 4a, 4b of the dividing walls 
4' that limit the one flow channel 17" run approximately conically from 
one another, as a result of which the entry cross-section of the jet 18 
can be kept as small as possible and the efficiency of the ejector pump 
can be increased. 
In FIG. 1, dividing walls 4 of the that type which serve as flow management 
profiles are drawn with dashed lines. In the implementation example shown, 
the dividing walls 4 primarily assume the following three functions: 
First, they provide the profiles 1 through 3 with support, and prevent them 
from oscillating from the effects of the flow turbulence that develops in 
the flow channel. 
Second, the housing 5 can be mechanically stabilized by them as well. 
Third, they reduce the spread of the flow turbulence into the mixing zones, 
and thereby shorten the required flow channel length, as seen in the 
direction of flow. They therefore improve the flow character in the sense 
of the invention, even without the presence of the profiles 1 through 3 
that are oriented perpendicular to them, and as such, they can be used 
alone as well. 
The system, shown in FIG. 2, of transverse and longitudinal profiles 1 
through 3 and dividing walls 4 that can be built into the flow channel 17, 
can be manufactured and assembled in a simple way by virtue of the fact 
that each one of the dividing walls is provided with the profiles 1 
through 3 on one or both sides, and specifically, is manufactured together 
with them as one piece, in conjunction with which corresponding guides, in 
the form of holes and dowel pins 25 which are aligned with each other, are 
provided on the opposite dividing walls and the free ends of the profiles 
1 through 3. It is even possible, and especially advantageous, to 
manufacture complete segments or ejector pump modules 50, 60, consisting 
of the corresponding segments of the ejector housing and the flow 
management profiles, as shown in FIGS. 5 and 6, as a single component, out 
of plastic for example, and to provide it with end walls or to join it 
together with additional such segments or modules in order to attain the 
desired or necessary pumping capacity. Beyond that, it is also possible to 
make the number of stages of the pump variable by means of the fact that 
the ejector housing and the flow management profiles can be separated and 
joined together approximately perpendicular to the primary direction of 
flow (A) (see the schematically shown dividing line B, shown by means of a 
dashed line in FIG. 1). 
The implementation example in accordance with FIG. 3 shows how the system 
of flow management profiles 1 through 4 in accordance with FIG. 2 can also 
be formed in a circular fashion instead of running straight. 
With the ejector pump module 60, which is shown in perspective in FIG. 5, 
an ejector pump in the shape of a circle or of a segment of a circle can 
be built up--as has already been mentioned--by joining to one another 
several ejector pump modules 60. 
The ejector pump module 60 that is manufactured as one piece is comprised 
of a housing part 50, which exhibits a horizontal projection in the shape 
of a segment of a circle and in which are integrated--near the top of FIG. 
5--the suction chambers 7' through 10', which are joined with the flow 
channel 17' by means of the pass-through slots 21'. The termination of the 
chambers 7' through 10' in the axial direction--that is, towards the 
bottom of FIG. 5--is formed by an end wall 26', which exhibits in each 
suction chamber at least one inlet 16' for the medium to be transported, 
which inlet can in turn be equipped with a check valve. As is shown in 
FIG. 6, the inlets 16' join the suction chambers 7' through 10' with a 
chamber 27' which is placed beneath the end wall 26' and which serves as a 
distribution chamber for the fluid to be transported. Corresponding to the 
implementation example in accordance with FIG. 1, there are provided in 
the axial direction and to the side of--that is, in the top half of FIG. 
5--the second through the fourth pass-through slots 21', profiles 1' 
through 3' which are supported at a radial dividing wall 4' of the housing 
5C, which wall simultaneously closes off the suction chamber chambers 7' 
through 10' in the axial direction. The remaining open side of the suction 
chamber chambers 7' through 10' are closed by the separating wall 4' of 
the next (connected to it) ejector pump module 60. The upper termination 
of the ejector pump is formed--in a way similar to the form of 
implementation in accordance with FIG. 1--by a housing upper part (not 
shown) that exhibits in its center a--also not shown in the drawing--entry 
jet for the driving medium. The housing upper part can be comprised of a 
simple, lid-like component; it can, however, also be advantageous to place 
in the housing upper part additional suction chambers, which are opposite 
the suction chambers 7' through 10' and which are likewise joined with a 
chamber that holds the fluid that is to be transported. 
It is understood to be in the sense of the invention, that the pass-through 
slots 21 can also be realized in the form of openings that lie adjacent to 
one another, and that the openings 24 can also be realized as pass-through 
slots, and that as a result, the pass-through slots 21 at the suction 
chambers and the openings 24 at the hollow flow management profiles are to 
be considered means that act in the same way. 
As an alternative to the implementation example in accordance with FIG. 1, 
it is also comes into consideration to form the flow channel walls 17A, 
17B in the region of the diffuser 20 concave when seen transversely to the 
primary direction of flow, that is, hollow--and thus with a certain 
corresponding matching of the surface of the profiles 1 through 3, which 
is convex in this region. As a result of these measures, it is possible to 
have an advantageous effect on the course of the flow in the diffuser and 
the suction action at the subsequent pass-through slot 21. By way of 
example, a shaping of the flow channel wall of that type is shown by means 
of a dashed line 17A' in FIG. 1 at the flow channel wall 17A at the level 
of the profile 3. 
List of Reference Symbols 
1 Profile A Primary direction of flow 
2 Profile B Dividing line 
3 Profile 
4 Dividing wall 
5 Ejector housing 
5A Housing part 
5B Housing part 
5C Housing part 
6 Entry chamber 
7 Suction chamber 
8 Suction chamber 
9 Suction chamber 
10 Suction chamber 
15 Inlet (driving medium) 
16 Inlet (mixture of materials) 
17 Flow channel 
17A Flow channel wall 
17B Flow channel wall 
17C Longitudinal center plane 
18 Jet 
19 Mixing zone 
20 Diffuser 
21 Pass-through slot 
22 Outlet 
23 Suction chamber 
24 Openings 
25 Guide pins 
26 End wall 
100 Ejector pump 
50 Ejector pump module 
60 Ejector pump module 
70 Ejector pump 
27 Chamber