EP0674941A1 - Device for making an oil-water emulsion - Google Patents

Abstract

An assembly to form an emulsion of oil and water is operated in conjunction with esp. a diesel fuel injection pump and incorporates: (a) a symmetrical centrifugal chamber (1); (b) a surrounding coaxial ring passage (8) into which oil or diesel fuel is introduced through an inlet (9); (c) a water inlet jet (5) positioned in the vicinity of the chamber (1) fuel inlet (9); (d) a coaxial aperture (22) linking the chamber (1) and outlet (6); and (e) a priming tube (47) to the injection pump. The novelty is that a baffle plate (10) is located in the centrifugal chamber (1) coaxially opposite the inlet jet (5). The axial distance of the baffle plate (10) to the injection jet (5) is greater than the axial distance from the inlet (9) to the injection jet (5). The distance of the baffle plate (10) to the injection jet (5) is adjustable. <IMAGE>

Description

The invention relates to a device for forming an oil-water emulsion for the operation of an injection pump with the features described in the preamble of claim 1.

Such emulsifiers mix the oil and the water to form an emulsion in which the smallest water droplets are suspended in the diesel oil. If such oil-water emulsions are injected into the combustion chamber of an internal combustion engine, the combustion temperature and, as a result, the soot and nitrogen oxide content in the exhaust gas can be reduced.

From DE 39 12 344 A1 a generic device is known in which the oil is fed into the swirl chamber via inlet slots oriented tangentially to the swirl chamber, while the water is injected electronically into the inflowing oil in an electronically controlled manner by means of an injection nozzle. Oil and water are mixed together by the two flowing streams. The suspension obtained in this way is then accelerated by a tapering axial outlet of the swirl chamber and, in the turbulent state, passed onto an electrically driven radial impeller. The impeller, which is driven at high speed, creates a large pressure ratio between the outlet and inlet pressures and thus favors the formation of emulsions. Although a very fine and homogeneous emulsion is formed in the known device, this device still has disadvantages. In particular, the use of a separately driven radial impeller for the production of a homogeneous emulsion requires great design effort and represents an additional energy consumer on a diesel engine, for example. As a result, the known device is expensive to manufacture and leads to a deterioration in the overall mechanical efficiency of the diesel engine.

The invention is therefore based on the technical problem, starting from a generic emulsifying device, to show a device which forms a fine, homogeneous emulsion with purely fluid-mechanical means, is simple to construct and can be produced inexpensively.

The features given in claim 1 serve to solve the problem.

An advantage of the arrangement according to the invention of the baffle surface coaxially opposite the water injection nozzle in the swirl chamber is that the water jet injected under high pressure into the swirl chamber at high speed strikes the baffle surface axially, thereby causing the supplied water mass flow in the swirl chamber to be set into a highly turbulent flow . This vortex flow generated according to the invention mixes with the fuel supplied in a plane perpendicular to the direction of the water injection jet over the circumference of the vortex chamber without additional energy supply from the outside to form a fine emulsion.

Due to the proposed injection directions and the high kinetic energy of the injected water jet of the fuel admixture, the turbulent water-oil mixture in the collision space of the swirl chamber is additionally circulated and with the inflowing oil, such as. B. fuel swirled. This admixture of fuel to the high-energy and highly turbulent water flow achieves a uniformly good mixing of the smallest water and fuel-oil droplets.

The flow or swirling energy required to form such a homogeneous emulsion is applied according to the invention solely by using the energy potential of the injection jets, so that a previously required additional energy supply from the outside, for example in the form of a driven radial impeller, can be dispensed with, without thereby affecting the quality to affect the emulsion to be produced.

It is advantageous for an effective or evenly fine distribution of fuel and water if the inlet openings connecting the annular channel to the swirl chamber are aligned radially to the swirl chamber. As a result of this alignment, the fuel is distributed over the entire circumference of the swirl chamber in the direction of a central point in the swirl chamber which lies on the central longitudinal axis of the swirl chamber and consequently in the water injection jet. This fuel flow, which is fed in at the circumference, additionally supports the circulation for distributing the narrow fuel-water gap, particularly into your collision area. Furthermore, if the axial distance between the baffle surface to the injection nozzle is greater than the distance from the injection nozzle to the plane of the inlet openings, then the circulation flow supported by the fuel addition can be made unhindered for a fine distribution of both emulsion substances.

This swirling can be further intensified if, as in a preferred embodiment, an even number of injection openings is provided, two of which are coaxially opposite each other. The injection jets, which lie on a common diameter line and are directed inwards in the radial direction, inevitably meet head-on in your central point and thus optimize the swirling of the emulsion liquids into extremely fine droplets.

Since, depending on the distance between the baffle and the injection nozzle, the intensity of the turbulence of the injected water generated by the impact can be influenced, it can be advantageous if the axial distance between the baffle and the injection nozzle can be adjusted, in order thereby to apply the emulsifying device to the to match the injection pressure conditions and the desired droplet size of the emulsion to be produced.

A further advantage here is provided by the embodiment of the invention according to claim 4, in which the structural design for fastening the baffle plate is laid in the flow direction of the emulsifier. A disturbance in the emulsified throughput by the device according to the invention is thus avoided. At the same time, this configuration additionally creates the prerequisite for a possibility of adjusting the distance of the impact surface to the injection nozzle from outside the device according to the invention, that is to say without complex, partial disassembly. A suitable embodiment is the subject of claim 5.

Furthermore, in the device known from the prior art from DE 39 72 344 A1, the return of the emulsion coming from the injection pump in a return line to the emulsion circuits has been found to be the cause of a non-consistently homogeneous emulsion formation. The unused emulsion portion returns directly to the circuit via the suction chamber of the radial impeller and thus leads to local changes in the concentration of the oil-water premix that flows into the suction chamber through the tapered outlet of the swirl chamber. In addition, depending on the amount of the return, a backflow-related backflow into the swirl chamber and an associated inadequate mixing of water and oil can result.

In order to feed the unused emulsion into the emulsification circuit without additional agitator and thus to re-mix it, an embodiment is shown in claim 6 in a further development of the invention, the advantage of which is that the return emulsion is first collected in a feed channel and over the entire circumference the mixing chamber is distributed before it is mixed through a backflow channel into the emulsification circuit and thus into the freshly produced emulsifier. In this way, the return emulsified is led into the area of the connection opening, where the emulsified flow coming from the swirl chamber flows into the mixing chamber at high speed due to the nozzle effect at the connection opening. In addition to the turbulence occurring in this area, it is in particular the suction effect of the fast flow which, according to the invention, regulates the quantitative metering of the return to the emulsified flow in such a way that complete mixing of the return is achieved by means of fluid mechanics and disadvantageous influencing or partial calming of the fresh -Emulsified gas flow in the mixing chamber can be avoided.

The device according to the invention is also characterized by an extremely low pressure volume, since its chamber system is matched to a continuous emulsion volume flow in terms of fluid mechanics and has no partial volumes lying in the flow shadow.

In order to be able to adapt the device according to the invention designed for a certain volume flow and a certain maximum achievable water content of the emulsion formed to larger volume flows required by consumers, it is provided in a further development of the invention to connect several devices according to the invention to a common collecting housing, from which in turn the Injection pump can be fed with the required volume flow.

Further refinements and advantages of the invention emerge from the remaining subclaims and the description.

Two embodiments of the invention are shown in the drawing and are described in more detail below.

• Figur 1: Einen Längsschnitt der erfindungsgemäßen Emulgiervorrichtung;
• Figur 2: Eine Querschnittsdarstellung auf Höhe des Kollisionsraums der Wirbelkammer entlang des Schnittverlaufs 11-11 in Figur 1;
• Figur 3: Ein weiteres Ausführungsbeispiel der erfindungsgemäßen Vorrichtung mit einer Sammelleitung im Längsschnitt.

Show it:

• Figure 1: A longitudinal section of the emulsifying device according to the invention;
• Figure 2: A cross-sectional view at the level of the collision space of the swirl chamber along the section 11-11 in Figure 1;
• Figure 3: Another embodiment of the device according to the invention with a collecting line in longitudinal section.

The embodiment of the device according to the invention shown in longitudinal section in FIG. 1 is already equipped with connection flanges 30, 32, 34 and line couplings 31, 33, 35 connected to the respective inlets 3, 7 and outlet 6 for better understanding of the structure and function .

The device itself essentially consists of a housing 48, a chamber system 1, 2, 19 formed in the housing 48, the oil, water and return flow systems as well as an impact ram assembly 13 with adjustment mechanism 14.

The housing 48 is made of four machined and screwed together coaxially ro tion-symmetrical housing parts 36, 37, 38, 39 assembled and encloses a rotationally symmetrical axial passage opening. The subdivision of the housing 48 is chosen so that the constructive design of each of the housing parts 36, 37, 38, 39 respectively the mutually facing and screwed end faces of two housing parts 36, 37, 38, 39 divide the through hole into three chamber sections.

In the first of these chamber sections between the housing parts 36, 37, a nozzle insert 26 is inserted coaxially, by means of which a rotationally symmetrical swirl chamber 1 is separated from the subsequent chamber sections. The shape of this swirl chamber 1 is limited by a cylindrical collision space 27 formed in the housing part 36 and the inner diameter of the nozzle insert 26 which is smaller in diameter and adjoining it in the direction of flow 25.

As shown in FIG. 2, six radially aligned inlet openings 9, which are formed in a plane perpendicular to the longitudinal axis 28 of the vortex chamber, open into the collision space 27 at uniform angular intervals over the circumference. The inlet opening 9 does not necessarily have to be arranged at uniform angular intervals; rather, these inlet openings can also be provided distributed irregularly over the circumference, in order to thereby achieve an additional flow control. The inlet openings 9 connect the swirl chamber 1 to an annular channel 8 which is arranged coaxially around it on the outer wall of the housing. This annular channel 8 is delimited by an annular housing 29 which is preferably welded to the outer wall of the housing or screwed onto it and serves as a compensation volume for the oil or fuel supply to the device according to the invention. The volume of the ring channel 8 and the total opening cross-section of the inlet openings 9 are coordinated with one another in such a way that, based on the intended delivery rate of a fuel supply pump, ensures that all inlet openings 9 are supplied with a sufficient amount of fuel without the need for supplying the injection pump Fuel flow is limited in any way.

Radially on the ring housing 29 there are one or more connection flanges 30, 30 ', each of which connects one or more fuel low pressure lines (not shown) connected to the ring channel 8 via a diesel inlet 3 by means of line couplings 31. If, as shown in the exemplary embodiment shown, a plurality of connection flanges 30, 30 'are formed, then only the connection flange which is favorable under the prevailing installation conditions can be connected to the fuel supply line, while the remaining line flanges 30' can be closed by means of threaded plugs 40.

The end face of the swirl chamber 1 facing your housing part 26 is defined by a water injection valve 4, which is screwed into the front end of the housing passage opening and whose injection nozzle 5 opens into the swirl chamber 1.

An electromagnetic valve is used as the water injection valve 4, against which a water delivery pump (not shown here) conveys water and builds up a selected dynamic pressure. The water injection valve 4 is opened and closed by means of corresponding electrical control pulses from a control unit, also not shown, and water is injected under pressure through the injection nozzle 5 into the swirl chamber 1. Here, the electromagnetic injection valve 4 is distinguished by a fast and precise opening and closing behavior, as a result of which even high-frequency intermittent injection can be controlled precisely.

The injection nozzle 5 of the water injection valve 4 opens coaxially into the swirl chamber 1 and guides the water injection jet essentially likewise coaxially into the swirl chamber 1. There, the injection jet hits a baffle surface 10 of a baffle plate 11, which is in a plane perpendicular to the water injection direction the swirl chamber 1 is arranged. The baffle surface 10 is positioned at a distance from the water injection nozzle 5, which on the one hand allows the radially oriented oil or fuel injection jets from the inlet openings 9 to meet each other freely in the horizontal center of the swirl chamber, and on the other hand the water injection jet in the vertical direction therethrough The center of the chamber and the quantities of fuel that meet there radially are sprayed through against the baffle surface 10 and the water spraying again from the baffle surface 10 is at least partially directed back into the inlet end section 27 against the water injection direction. Consequently, the fuel injection jets and both the water injection jet and the water spraying back from the baffle surface 10 collide with one another in the most diverse directions in this inlet end section 27 and thus mix in the highly turbulent flow thereby produced to form a homogeneous emulsion.

The baffle plate 11 forms the front end of an impact ram 12, which is connected to an adjusting mechanism 14 and from the front side of the housing part 39 coaxially through the cam mer system, which is described in more detail below, extends into the swirl chamber 1. In this installation position, the end of the impact ram 13 is guided through a nozzle opening 22 which is formed with a corresponding diameter centrally in the bottom of the nozzle insert 26.

However, the invention is not limited to the design of the baffle plate attachment shown in this embodiment, but it can, as for. B. in the embodiments of the invention shown in FIG. 3, an impact ram 13 'can be fastened in its position in the housing part 39' without an adjustment mechanism; An insert body suitable for positioning the impact surface 10 is also conceivable, which is inserted into the nozzle insert 26 but does not hinder the emulsification flowing through. In the embodiment shown in FIG. 1 with adjusting mechanism 14, this is inserted with a precise fit into a corresponding receiving bore 18 in the housing part 39 and is fixed in position on the flange 16 by means of a clamping nut 15.

The adjustment mechanism 14 is composed of a sliding piece 41 with an internal fine thread and a threaded bolt screwed into the fine thread. The threaded bolt is connected in a rotationally fixed manner to the end of the impact piston 12 facing away from the baffle plate 11 and has a handle part 17 protruding from the housing part 19, with which the impact piston 12 can be moved in the axial direction to adjust the baffle surface distance. Of course, the person skilled in the art is familiar with a large number of different length adjustment mechanisms, which should likewise be covered by the scope of protection of the present invention.

So that the strong turbulence of the vortex flow in the inlet end section 27 is not impaired by an increase in the baffle distance from the injection nozzle 5, a taper 42 is formed on the inner edge of the sleeve, the slope of which is selected so that it radially pushed beyond the baffle plate 11 Water or water-oil mixture is partially directed to the slope and can flow back towards the injection nozzle 5 into the inlet end section 27. Thus, on the one hand, a flow circulating back into the collision space 27 is formed by means of the taper 42, on the other hand, this taper 42 acts as an acceleration ring channel for the emulsion stream flowing out of the collision chamber 27 into the adjacent part of the swirl chamber 1. The accelerating effect of this taper 42, as well as the nozzle opening 22, supports the hydrodynamic distribution of the finest water and fuel particles among one another.

The vortex chamber 1 is connected in the flow direction 25 via the nozzle opening 22 to the subsequent chamber system, which comprises a mixing chamber 2 and a collecting chamber 19.

The mixing chamber 2 is delimited by the inner wall of an insert sleeve 43 inserted into the chamber section 45 formed by the housing parts 37 and 38 and the section of the passage opening of the same diameter in the housing part 38 and opens downstream into the larger-diameter suction chamber 19 via a divergent transition 44.

A collar 46 is formed on the insert sleeve 43 at its downstream end, in the direction of flow 25, with which it is axially supported against an inner shoulder of the housing parts 37 and 38, respectively. The outer diameter of the insert sleeve 43 is dimensioned such that a return flow channel 24 in the form of a hollow cylinder is delimited by the inner wall of the chamber section 46 and the outer sleeve wall. The axial length of the insert sleeve 43 is dimensioned smaller than the length of the chamber section 45, so that the return flow channel 24 is connected to the mixing chamber 2 via a radial opening 23 extending over the entire circumference of the sleeve at the emulsion transition area between the swirl chamber 1 and the mixing chamber 2.

At the upstream end of the return flow channel 24, a feed channel 20 is also formed in the housing part 38, which is toroidal and coaxially surrounds the mixing chamber 2. In this feed channel 20, a return inlet 7 opens radially, to which a return line (not shown) coming from the injection pump is connected with a line coupling 33 arranged laterally on a ring piece 38a. The ring piece 38a is screwed onto the housing part 38 and forms the outer boundary of the feed channel 20 in the radial direction 38a.

The emulsate returned to the emulsifying device in this return line first reaches the toroidal feed channel 20 and then flows against the flow direction 25 through the return flow channel 24 up to the radial opening 23 into the passage area of the nozzle opening 22.

Due to the inventive design of the return flow path through which the return emulsate has to flow before it is mixed into the emulsate stream, the return flow is subjected to multiple changes of flow direction, whereby flow turbulence is generated in each case, which causes mixing of the return emulsate.

Because of the nozzle opening 22, the emulsified stream flowing out of the swirl chamber 1 is accelerated as it passes and occurs at a high rate Flow rate in the mixing chamber 2. Due to the high flow rate of the emulsifier, a negative pressure is generated in this transition area. This negative pressure initially causes a turbulent swirling of the emulsified flow in the mixing chamber 2; but it also has the effect that the return emulsifier fed in through the return line is sucked in through the radial opening 23 and entrained by the emulsifier stream. This admixture of the return emulsifier based on the suction effect and the turbulent flow in the emulsate stream results in renewed mixing of the return emulsifier, so that finally a fine, homogeneous emulsate flows into the collecting chamber 19.

From the collecting chamber 19, the homogeneous emulsified formed is fed through the outlet 6 through a feed line (not shown) to the injection pump. The embodiment of the device according to the invention shown in FIG. 3 largely corresponds to the embodiment shown in FIGS. 1 and 2. For this reason, the same parts are provided with the same reference numerals, if possible. FIG. 3 shows the device according to the invention as it is screwed into a bottle 50 of a manifold 49 and is conductively connected to the latter via an outlet opening 51. Here, the housing part 39 'is modified compared to the embodiment shown in Figures 1 and 2 and opened in the axial direction. In the area of the opening side of the housing part 39 'screwed into the flange 50, the impact ram 13' is inserted and fixed. For this purpose, the impact ram 13 'is formed with a ram base 53 which is clamped between your stop 53 and the shoulder 55. The plunger base 53 has a plurality of bores 54 aligned in the flow direction 25, through which the fuel-water emulsion formed can flow through the outlet opening 51 into the collecting line 49.

By adapting several emulsifying devices to a collecting housing, as shown in FIG. B. the manifold 49, the volume flow can be adapted to the needs of different consumers.

Reference list

• 1 swirl chamber
• 2 mixing chamber
• 3 diesel inlet
• 4 water injection valve
• 5 injector
• 6 outlet
• 7 return entry
• 8 ring channel
• 9 inlet openings
• 10 baffle
• 11 baffle plate
• 12 shaft
• 13.13 'impact stamp
• 14 adjustment mechanism
• 15 clamping nuts
• 16 flange
• 17 handling part
• 18 location hole
• 19, 19 'collection chamber
• 20 feed channel
• 21 inlet bore
• 22 nozzle opening
• 23 radial opening
• 24 reverse flow channel
• 25 flow direction
• 26 nozzle insert
• 27 collision room
• 28 longitudinal axis
• 29 ring housing
• 30, 30 'connecting flange
• 31 cable coupling
• 32 connecting flange
• 33 cable coupling
• 34 connecting flange
• 35 cable coupling
• 36 housing part
• 37 housing part
• 38, 38 'housing part
• 39, 39 'housing part
• 40 threaded plugs
• 41 sliding piece
• 42 rejuvenation
• 43 insert sleeve
• 44 divergent transition
• 45 chamber section
• 46 fret
• 47 flow line
• 48 housing
• 49 manifold
• 50 flange
• 51 outlet opening
• 52 stop
• 53 stamp base
• 54 hole
• 55 paragraph
• 56 threaded connector

Claims (11)

1. Device for forming an oil-water emulsion for the operation of an injection pump, in particular an injection pump of a diesel engine, with - A rotationally symmetrical swirl chamber (1) into which an oil channel or diesel fuel is supplied in one plane coaxially surrounding the swirl chamber (1) and connected to it by inlet openings (9), - A water injection nozzle (5) coaxially opening into the area of the inlet openings (9) of the swirl chamber (1), - a coaxial connection opening (22) which connects the swirl chamber (1) to an outlet (6), - to which a flow line (47) leading to the injection pump is connected,
characterized in that an impact surface (10) coaxially opposite the water injection nozzle (5) is provided in the swirl chamber (1), the axial distance between the impact surface (10) and the injection nozzle (5) being greater than the axial distance between the inlet openings (9) to the injection nozzle (5) and that on at least one center line that intersects the axis of symmetry of the swirl chamber (1), two inlet openings (9) are arranged opposite each other and aligned coaxially to the center line. 2. Device according to claim 1, characterized in that the impact surface (10) is adjustable in its axial distance from the injection nozzle (5). 3. Apparatus according to claim 1, characterized in that an even number of inlet openings (9) is provided. 4. The device according to claim 1, characterized in that the baffle (10) is formed on the end face of an impact ram (13) which is coaxial through the connection opening (22) projecting into the swirl chamber (1) is provided. 5. Apparatus according to claim 2 and 4, characterized in that the impact ram (13) is connected to an adjusting mechanism (14) by means of which it is designed to be displaceable in the axial direction. 6. The device according to one or more of claims 1 to 5 with a coaxial to the swirl chamber (1) and with this via a connecting opening (22) connected to the rotationally symmetrical mixing chamber (2) into which a return inlet (7) opens, at which one of The return line coming to the injection pump is connected, characterized in that the return inlet (7) opens into a feed channel (20) which coaxially surrounds the mixing chamber (2) and which opens into the mixing chamber (2) via a radial opening (23). 7. The device according to claim 6, characterized in that the return inlet (7) is formed in a flow direction (25) of the emulsifier axial distance to the connecting opening (22), and that the feed channel (20) against the flow direction (25) a return flow channel (24) is connected to the radial opening (23). 8. The device according to claim 7, characterized in that the return flow channel (24) is in the form of a coaxially surrounding the mixing chamber (2) surrounding hollow cylinder, which via the radial opening (23) in the transition region between the swirl chamber (1) in the mixing chamber (2) opens in the radial direction. 9. Device according to one of claims 6 to 8, with a collecting chamber (19), on which the outlet (6) is arranged downstream, characterized in that the collecting chamber (19) is arranged axially to the mixing chamber (2), and the Mixing chamber (2) is designed to be open via a divergent transition (44) to the collecting chamber (19). 10. The device according to one or more of claims 1 to 9, characterized in that one or more devices on the output side with a collecting tube (49) are designed to be conductively connectable.

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