High Pressure Homogenizer

Abstract

The present invention relates to a high-pressure homogenizer (1) for particle-filled flowable materials, comprising a high-pressure chamber (2), a homogenization unit (3) fluidly connected downstream of the high-pressure chamber and adapted to relax the fluid to be homogenized under turbulence, the fluid being previously pressurized in the high-pressure chamber to a pressure of more than 500 bar, a plunger pump (4) assigned to the homogenization unit (3) and having a plunger (5) for pressurizing the high-pressure chamber (2), and a cooling device (6) adapted to surround the plunger shaft (6) and cool the plunger (5), N and a low-pressure chamber (7) having an operating pressure of ≦25 bar, the low-pressure chamber (7) and the high-pressure chamber (2) being separated from each other by a seal (8) through which the plunger (5) passes, the seal (8) being a throttle gap formed between the plunger shaft (6) and a bushing (9) that does not contact the plunger shaft (6), the length (L) and the radial annular gap height (S) of which S / L ≦0.0015 apply.

Description

[Technical Field]

[0001] The present invention relates to a high-pressure homogenizer for particle-filled flowable materials according to the preamble of claim 1. [Background technology]

[0002] During homogenization, the particles of the suspension are dispersed as uniformly as possible. To this end, the fluid to be homogenized is pumped through a homogenization unit in a homogenizer. In the homogenization unit, turbulence is generated in conjunction with targeted shear forces and cavitation to separate agglomerates in the fluid to be homogenized.

[0003] So-called plunger pumps are often used to pump fluids into homogenizing units. A plunger pump is a positive displacement pump in which the piston rod (so-called plunger) itself acts as the piston. In this case, the piston does not reach the cylinder wall. Therefore, no seal is needed between the piston side and the cylinder wall. In plunger pumps, a seal is needed between the working space and the plunger (usually at the inlet of the working space).

[0004] It is known to provide plunger cooling to protect plunger pumps from overheating during operation, and research into this has shown that the fluid being homogenized can be used to cool the plunger.

[0005] For this purpose, the plunger can be guided through a cooling chamber. During operation, the plunger heats up mainly in the area located in the working space, so the cooling chamber is preferably adjacent to the working space of the pump. This ensures that the plunger is cooled close to the heat generation zone. The fluid to be homogenized is preferably used as the coolant. In this case, the fluid is pumped through the cooling chamber before reaching the working space of the plunger pump. In doing so, it flows around the plunger, cooling it. From the cooling chamber, the fluid is finally delivered to the working space.

[0006] Because high pressures must be created within the working space, the working space must also be adequately sealed from the surroundings, i.e., the cooling chamber. A plunger-contacting seal is typically used for this purpose. This creates wear on the seal due to plunger movement, especially when pumping fluids containing solid particles. Furthermore, such seals are often difficult to install because they must typically be installed under bias to minimize relative movement between the seal and the housing that encloses it. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above background, it is an object of the present invention to provide a high-pressure homogenizer that can reduce wear on the seal between the working space and the cooling chamber. [Means for solving the problem]

[0008] This problem is solved according to the invention by the features of the independent claims relating to a high-pressure homogenizer.

[0009] The object is thus achieved by a high-pressure homogenizer for flowable materials filled with solid particles (sometimes simply referred to herein as "particles"), comprising at least one high-pressure chamber and at least one homogenization unit fluidly connected downstream of the at least one high-pressure chamber. The homogenization unit functions to relax the fluid to be homogenized, which typically has a viscosity of 20 mPas or more and is previously pressurized in the at least one high-pressure chamber at more than 500 bar, under turbulence. The homogenization unit is designed accordingly.

[0010] The high-pressure homogenizer further comprises a plunger pump assigned to the homogenization unit, at least one plunger of which pressurizes the high-pressure chamber. In this case, the high-pressure homogenizer comprises a low-pressure chamber surrounding the plunger shaft and for cooling the plunger. The low-pressure chamber is P N The high-pressure homogenizer has an operating pressure of ≦25 bar. The low-pressure chamber and the high-pressure chamber are separated from each other by a seal through which the plunger passes. The high-pressure homogenizer according to the present invention is characterized in that the seal through which the plunger passes is a throttle gap formed between the plunger shaft and a solid bushing that does not contact the plunger shaft (or does not substantially contact it because it has no significant defects). With respect to the length L of the throttle gap and the radial annular gap height S, the following applies: S / L ≦0.0015. The term length L in this context refers to the so-called cylindrical length. This length refers to the cylindrical length of the annular gap (excluding unavoidable geometric tolerances), and therefore does not include the inlet and outlet areas of the gap that form chamfers or radii.

[0011] Embodiments of the present invention have many advantages.

[0012] The fluid is completely or substantially completely relaxed in the homogenization unit so that any accumulations of solid particles in the fluid are separated from one another and substantially uniformly dispersed throughout the fluid.

[0013] An advantage of the plunger pump used to feed the homogenization unit is that it can generate vibrations in the fluid stream being fed to the homogenization unit, further improving the homogenization effect. In this case, the plunger pump can have only one drive plunger or multiple drive plungers (preferably with offset dead centers). The latter can potentially have the advantage of increasing the frequency of vibrations and reducing the amplitude, which is important for strength.

[0014] The advantage of a plunger pump with multiple plungers is that the fluid to be homogenized can be supplied to the homogenization unit continuously, rather than in a burst, by simply driving each plunger to reach bottom dead center at an offset time relative to the other plungers.

[0015] The plunger stem of at least one plunger passes through the low-pressure chamber of the plunger pump, so that the fluid to be homogenized flows around the plunger, which reduces the inevitable heating of the plunger during pumping and improves the efficiency of the pump.

[0016] In any event, the seal between the high pressure chamber and the low pressure chamber functions substantially, and preferably completely, without contact.

[0017] The seals are adequately lubricated by the inevitable leakage flow, which, depending on the viscosity of the fluid, occurs at least as a drag leakage, and usually as a gap leakage due to pressure differences, in which case the leakage flow is collected from the high pressure chamber to the low pressure chamber and then returned to the high pressure chamber without causing any problems.

[0018] The present invention overcomes the prejudice that gap seals with very small gap heights are out of the question for sealing particulate-laden fluids, since the pressure differentials involved in the present invention would be expected to cause problems within a short time due to the accumulation of solid particles introduced into the gap with the fluid.

[0019] Surprisingly, it has been found that in the gap design associated with the present invention, the gap is essentially free of harmful accumulation of solid particles, and the oscillating movement of the plunger within the seal keeps the seal gap fully functional.

[0020] Instead of the term "high pressure homogenizer", the term "disperser" can also be used.

[0021] The term "plunger" refers to the piston formed by the piston rod.

[0022] The term "high pressure chamber" refers to the working space of a plunger pump.

[0023] The term "cooling chamber" refers to the low pressure chamber of a plunger pump.

[0024] The term "contactless seal" refers to the bushing of the high-pressure seal contacting the outer side of the plunger, but does not exclude the high-pressure seal contacting other components of the plunger pump.

[0025] The term "downstream fluidly connected homogenization unit" refers to the fluid to be homogenized flowing from the high pressure chamber towards the homogenization unit.

[0026] There are many possibilities to further improve the effectiveness or usefulness of the present invention.

[0027] For example, it is particularly preferred that the cylindrical length L of the throttle gap (calculated without including any chamfers or radii on the end faces) is at least 2 / 3 of the plunger diameter. Ideally, the cylindrical length corresponds to at least the full diameter of the plunger.

[0028] Such a gap length suppresses the flow rate of the leak flow, which not only prevents an excessive amount of leak flow from flowing into the low-pressure chamber but also prevents problems such as firing when the leak flow enters.

[0029] In other preferred embodiments, the throttle gap has a maximum gap height of 0.03 mm. To explain this in more detail, in a particularly preferred embodiment of the invention, the bushing preferably has an inner diameter of 20 mm + 0.009 mm (taking into account its tolerances) and the plunger preferably has a maximum outer diameter of 20 mm - 0.02 mm (taking into account its tolerances), although this is not presently required.

[0030] Such gap height studies have given good results regarding pump efficiency.

[0031] Ideally, the end face of the bushing transitions to the inner side of the bushing via a chamfer on the side facing the high-pressure chamber. The chamfer is preferably configured as a flat chamfer with a chamfer angle of approximately 30° or less relative to the longitudinal axis of the plunger. Such a flat chamfer prevents or reduces hard impact of the piston against the bushing wall if the plunger is displaced from its center position during operation.

[0032] It has proven particularly advantageous to provide an angled chamfer, which on the side facing the high-pressure chamber consists of a steeper first section and includes a chamfer angle of approximately 45° relative to the longitudinal axis of the bushing. This first section is joined on the side facing the sealing gap by a second chamfer with a flatter chamfer angle, preferably of approximately 30° or less. A chamfer configured in this way optimally keeps solid particles away from the sealing gap.

[0033] Ideally, the end face of the bushing also transitions to the inner flank of the bushing via a chamfer on the side facing the plunger drive, which is usually configured to be steeper than the chamfer on the high-pressure chamber side.

[0034] The gap height between the plunger and the bushing is so small that there is a risk of damaging the bushing when the plunger is installed. A radius, bevel or chamfer on the end face of the bushing where the plunger is introduced reduces the risk of damage.

[0035] In particular, the flat chamfered portion helps to create a temporary drag effect towards the high pressure chamber opposite the leakage as soon as the plunger moves further into the high pressure chamber, thereby further reducing leakage.

[0036] Instead of a chamfered portion, a radius r may be provided at the relevant portion of the bushing.

[0037] "Plunger driver facing side" refers to the side facing the drive piston.

[0038] Preferably, the bushing and plunger are constructed from materials having different coefficients of thermal expansion.

[0039] Ideally, the thermal expansion coefficients of the components should be significantly different from each other. For example, if the plunger is made of ceramic and the bushing is made of steel, the seal gap will self-adjust. In the event of undesirable friction conditions, caused by excessive particle intrusion into the gap, for example, frictional heat will be generated within the gap. In this case, the different thermal expansion coefficients of the bushing and plunger and the frictional heat will tend to widen the seal gap. This will flush the gap again, thus negating the risk of potential damage associated with friction.

[0040] In another preferred embodiment, the plunger is constructed from a ceramic material.

[0041] This is an advantage as ceramic materials have a high resistance to wear, heat and pressure.

[0042] In this case, the plunger is preferably constructed from a solid ceramic.

[0043] In another preferred embodiment, the bushing is made of bearing metal.

[0044] This avoids damage due to direct frictional contact that may occur between the outer flank of the plunger and the inner surface of the bushing (for example during start-up or under the influence of fluid vibrations).

[0045] Furthermore, it is particularly advantageous if the bushing and plunger combination can be selected to substantially or at least partially compensate for different process temperatures. This is illustrated in the following example. As the process temperature increases, the temperature of the fluid to be homogenized increases. In this case, the fluid tends to become thinner. If the seal gap between the bushing and plunger is too narrow, lubrication problems and even seizure may occur. This can be countered by combining different bushing and plunger materials, which allows the seal gap to change gap height and improve lubrication.

[0046] In some cases, it may be a good option to configure and mount the bushing so that it expands more than the plunger with increasing temperature, in which case the expansion occurs in a way that increases the height of the seal gap. Conversely, in other cases, it may be advantageous to combine bushing and plunger materials in such a way that the seal gap decreases with increasing temperature.

[0047] As mentioned above, this protects the seal gap from damage due to particle buildup within the seal gap.

[0048] Ideally, the longitudinal axes of the bushing and the plunger shaft that moves back and forth within the bushing are consistently parallel or preferably coaxially aligned.

[0049] This ensures that the seal gap between the bushing and the outer side of the plunger shaft has a uniform gap height.

[0050] Advantageously, each plunger is driven by its own drive piston, which is assigned to it only and driven by the crankshaft, and in this case the drive pistons are connected to the crankshaft via pin bearings, which are arranged at different angles around the rotation axis of the crankshaft, and the drive pistons thus act as connecting rods.

[0051] In another preferred embodiment, the plunger is connected to a drive piston that drives the plunger via a universal joint coupling.

[0052] This allows the drive piston and plunger to pivot relative to each other while the movement of the drive piston is transmitted to the plunger. Due to the pivotability of the drive piston relative to the plunger, the plunger is only subjected to axial forces and is not subjected to forces acting radially on the bushing. Therefore, the movement of the plunger remains linear and substantially parallel to the longitudinal axis of the bushing.

[0053] Ideally, the drive end face of the plunger, or the end face of the drive piston that transmits the drive pressure to that end face, is convexly curved.

[0054] The curved end faces of the plunger and the drive piston facing each other allow the plunger and the drive piston to abut against each other without interfering with the rotation of the drive piston relative to the plunger. [Brief explanation of the drawings]

[0055] [Figure 1] 1 is a schematic diagram showing a high-pressure homogenizer according to the present invention. [Figure 2] FIG. 1 is a perspective view of a portion of a plunger pump (without the high-pressure chamber). [Figure 3] FIG. 3 is an enlarged view showing a part of the plunger pump in FIG. 2. [Figure 4]FIG. 1 is a top view of a plunger pump (with the high-pressure chamber removed). [Figure 5] 1 is a cross-sectional view A showing a first embodiment of a plunger pump. [Figure 6] 1B is a cross-sectional view showing the first embodiment of the plunger pump. FIG. [Figure 7] FIG. 7 is a partial cross-sectional view showing the first embodiment in FIGS. 5 and 6. [Figure 8] 8A is a cross-sectional view A showing a second embodiment of a plunger pump having a bushing held so as to be movable in the radial direction. 8A and 8B are explanatory diagrams showing the basic mobility of a bushing having a cylindrical outer peripheral surface. 8C and 8D are explanatory diagrams showing the basic mobility of a bushing having a spherical outer peripheral surface. [Figure 9] 10 is a cross-sectional view A showing a third embodiment of a plunger pump. FIG. [Figure 10] 10A is a cross-sectional view A showing fourth and fifth embodiments of the plunger pump. FIG. [Figure 11] FIG. 4 is a detailed view of a bushing according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0056] The operation of the high-pressure homogenizer will be described below with reference to FIGS.

[0057] The basic operation of the high-pressure homogenizer 1 can be easily understood from the schematic diagram of FIG.

[0058] The fluid to be homogenized is initially in a product storage container 28. From that container, the fluid is conveyed by a feed pump 29 via line 16 first to the low pressure chamber 7 and then to the high pressure chamber 2.

[0059] The entry of the plunger 5 creates a positive pressure in the high pressure chamber 2. This positive pressure closes the inlet valve 30 and opens the outlet valve 31. The plunger 5 is then withdrawn again from the high pressure chamber 2, but only to the extent that the end face 23 of the plunger 5 still remains within the high pressure chamber 2. At this time, a negative pressure is created in the high pressure chamber. This negative pressure closes the outlet valve 31 and opens the inlet valve 30, allowing liquid to flow into the high pressure chamber 2 again.

[0060] The high-pressure chamber 2 is sealed from the surroundings and the low-pressure chamber 7 by a seal 8 arranged in the housing 18. In this case, the seal 8 is arranged to surround the plunger 5. The seal 8 has an undersize (undersized) inner width of its inner cross section of preferably 0.015 mm to 0.03 mm, ideally about 0.02 mm. This results in a radial gap height S of 0.075 mm to 0.015 mm. This gap height preferably intersects the seal gap length L along the plunger longitudinal axis (which corresponds to at least 2 / 3 of the plunger diameter). According to the invention, the ratio S / L in this case is ≦0.0015 mm.

[0061] The plunger 5 together with its plunger shaft 6 is guided through a housing 17 and a low-pressure chamber 7 arranged in the housing 17. The fluid to be homogenized therefore flows around the plunger shaft 6 in the low-pressure chamber 7, thereby cooling the plunger shaft 6. In this case, the low-pressure chamber 7 is sealed against the surroundings by a low-pressure sealing device 25.

[0062] Ideally, a plurality of plungers 5 are connected in series. In this case, ideally, the individual plungers 5 are controlled so that they do not reach the bottom dead center at the same time, but rather reach the bottom dead center at different times.

[0063] 2 and 3 show such a plunger pump 4. In this case, the high pressure chamber 2 or the housing 32 forming the high pressure chamber 2 is not shown.

[0064] For clarity, the individual components in the plunger pump 4 are only referenced according to the plunger 5 and the associated elements of the plunger pump 4 .

[0065] Each plunger 5 of the plunger pump 4 is driven by a respective drive piston 12. In this case, the drive pistons 12 and the plungers 5 are connected to each other via a radially flexible coupling, for example in the form of a universal joint 13 (details omitted).

[0066] Plunger 5 projects through housing cover 26, housing 17 which surrounds or defines low pressure chamber 7, and housing 18 which surrounds high pressure seal 8. Adjacent housing 18 which surrounds high pressure seal 8 is housing portion 32 (not shown in FIG. 2) which defines high pressure chamber 2 shown in FIG. 1.

[0067] To connect the individual housing parts together, holes 21 are provided for fastening screws. Furthermore, to accurately position housing part 32 on housing part 18, two or more locating pins 20 are attached to housing part 18.

[0068] The individual low-pressure chambers 7 are connected to one another via connecting pipes 19. Thus, the fluid to be homogenized is conveyed via inlet 16 to one of the low-pressure chambers 7 and flows from there through the other low-pressure chambers 7 via connecting pipes 19. The fluid is finally discharged from the last low-pressure chamber 7 via outlet 16. From there it flows via a pipe (not shown) into the high-pressure chamber 2 (also not shown).

[0069] In order to connect the plunger 5 to the drive piston without the plunger being tilted against the bushing (which forms the sealing gap with the plunger) by the force of the drive piston, a radially flexible coupling is ideally used, as already mentioned briefly, as will be explained in more detail below.

[0070] 4 shows a bottom view of the arrangement in plunger pump 4. In this view, it is shown how section lines A-A and D-D pass through plunger pump 4.

[0071] Figure 5 shows a cross section along line A-A, in which the high pressure chamber 2 is shown diagrammatically.

[0072] The high pressure seal 8 for sealing the high pressure chamber 2 is made up of two gaskets 22 and a first bushing 9. One gasket 22 is directly adjacent to the high pressure chamber 2, while the other gasket 22 abuts against the housing 17. However, these gaskets are only secondary seals for the bushings 9, 24. The bushing 9, which surrounds the plunger shaft 6, is positioned between the two gaskets 22 and is held axially therebetween.

[0073] In the illustrated embodiment, the bushing 9 is fixedly arranged directly in the surrounding housing, in some cases so mounted that it is biased radially inwards with a pressure equal to that which subsequently acts on the sealing gap and which acts radially outwards.

[0074] A radial seal gap is formed between the bushing 9 and the side of the plunger shaft 6 (not shown in FIG. 5). A small amount of the fluid to be homogenized in the high-pressure chamber 2 can escape through the seal gap towards the low-pressure chamber 7. Due to the ratio of the seal gap height to the seal gap length, the pressure in the seal gap drops continuously down to the pressure of the low-pressure chamber 7, which has a positive pressure typically in the range of 3 bar. Normally, this positive pressure does not exceed 6 bar. The ratio of the seal gap height to the seal gap length is selected to reduce the amount of leakage, yet be large enough to avoid friction with particles that may be carried into the seal gap by the liquid.

[0075] The bushing 9 has a bevel 40 or chamfer or radius on its end face 10 facing the drive piston 12, which transitions to the inner side face, thereby advantageously preventing chipping of the end face edge in the event of impact contact with the plunger during operation. Complementarily, the plunger can be provided with a chamfer 41.

[0076] Within the housing 17 is a low pressure chamber 7 through which the fluid to be homogenized flows, cooling the plunger 5 before being fed into the high pressure chamber 2. The low pressure chamber 7 is sealed to the environment by a low pressure seal arrangement 25.

[0077] FIG. 5 also shows the technical aspects of a preferred radially flexible coupling.

[0078] As shown, the plunger 5 and the drive piston 12 are each held by a connection, not shown in detail. Both connections F1, F2 essentially provide the plunger 5 and the drive piston 12 with a defined pivotability relative to each other. As shown, the connections transmit the return stroke movement of the drive piston 12 to the plunger 5.

[0079] One end face of the plunger 5 or the drive piston 12 is formed convexly, which is preferably the end face of the drive piston, which is basically made of a softer material.

[0080] In this way, the drive piston 12 can "roll" a certain amount on the plunger 5. Any pivoting or lateral movements that may be produced by the drive piston 12 are therefore not transmitted to the plunger 5, so that the sealing gap is disturbed as little as possible. This is particularly important when the bushing 9 is mounted substantially radially immovable in the housing part 18 that surrounds it, as shown in FIG. 5.

[0081] In other words, the required pressure is transmitted from the drive piston 12 to the plunger 5 as it moves into the high-pressure chamber 2. The above-mentioned radially flexible coupling is installed to ensure that the longitudinal axes of the plunger 5 and the bushing 9 remain coaxial at all times during pumping. It should also be noted that the pulling force that returns the plunger 5 towards the drive piston 12 after it has reached bottom dead center is also transmitted from the drive piston 12 to the plunger 5 via the radially flexible coupling 13.

[0082] From the cross section B-B shown in FIG. 6 it can be seen how the low pressure chambers 7 are connected via connecting pipes 19.

[0083] From the section D-D shown in FIG. 7 it can be seen how the housing cover 26 is fixed to the housing part 17 surrounding the low pressure chamber 7 by means of fixing screws 27 .

[0084] FIG. 8 shows a second embodiment of the present invention.

[0085] What has been said about the first embodiment above applies to the differences described below unless otherwise specified.

[0086] The first difference from the first embodiment is that the bushing 9, which is involved in forming the sealing gap, is mounted so as to float. For this purpose, the outer periphery of the bushing is provided (at least partially, preferably completely) with a bearing sleeve 42 made of a somewhat compressible material, ideally a soft elastomer or rubber. The radial wall thickness of the bearing sleeve 42 is typically smaller than that of the bushing 9, typically at least two times smaller. Nevertheless, the outer lateral surface of the bushing 9 may be spherical rather than ideally cylindrical. This facilitates the pivoting movement of the bushing 9 when the bearing sleeve 42 is deformed.

[0087] The bearing sleeve 42 may be a separate component in the form of a sleeve or one or more rings, or may be a cast-in-place compound or vulcanized-in-place rubber body.

[0088] This type of bearing sleeve 42 allows the bushing 9 to translate or pivot a certain amount radially during operation, thereby allowing the bushing 9 to be adjusted relative to the plunger 5 so that the shape of the seal gap is optimized for seal quality or seal life.

[0089] This pivoting ability is also aided by elastomeric seal rings 22 which act as secondary seals and abut the end faces of bushing 9. Unlike solid retaining rings or washers, these seal rings 22 do not significantly pinch the end faces between them, and therefore do not impede the pivoting movement of bushing 9.

[0090] Figures 8a and 8b show how the pivoting of the bushing 9 adjusts the seal gap based on a bushing with a cylindrical outer surface, and Figures 8c and 8d show how the pivoting of the bushing is performed based on a bushing with a spherical outer surface.

[0091] Returning to Figure 8, a second difference, independent of what has been mentioned above, is that in the embodiment shown, the drive piston 12 and the plunger 5 are connected to each other via a rigid coupling, rather than via a radially flexible coupling as shown in Figure 5. This is because, in the embodiment shown, it is not necessary to prevent possible tilting movements of the drive piston relative to the plunger 5. This is not necessary in the embodiment shown, since the bushing 9 can adapt to the current position of the plunger 5 due to its flexible mounting (see Figure 8). This also makes it possible to avoid undesired lateral forces being transmitted from the drive piston that would impair the formation of the gap profile.

[0092] FIG. 9 shows a third embodiment of the present invention.

[0093] What has been said about the first embodiment above applies to the differences described below unless otherwise specified.

[0094] The main difference from the first embodiment is that the bushing 9 is made up of multiple parts. In this case, the bushing 9 is made up of multiple, ideally three, and more ideally at least four to eight, rings Ri1 to Ri5 that are in direct contact with each other and are mounted directly and sequentially. In the illustrated embodiment, the rings are fixedly mounted within the housing part 18 that surrounds the high-pressure seal. The division into individual rings greatly facilitates installation and removal during maintenance.

[0095] In some applications, it may also be highly advantageous to realize a graduated gap height profile that varies to some extent between adjacent rings Ri1 to Ri5. Thus, for example, it is conceivable to configure the first seal gap height, which is directed directly towards the high-pressure chamber 2, to be smaller than all or part of the following rings. This provides the option of avoiding excessive particle penetration along the length of the remaining seal gap, which has a larger gap height.

[0096] In a further option of this solution, the first ring Ri1 has a sacrificial function. That is, since the first ring has the smallest seal gap height, it crushes the particles that enter. In doing so, the first ring itself is subject to greater wear. However, in return, wear of the crushed / pre-crushed particles on the other rings Ri2 to Ri5 or Rin that constitute the seal gap downstream of the leakage flow and have a larger seal gap height is reduced.

[0097] Basically, the rings Ri1 to Rin described above are endless in the circumferential direction. However, in some cases it is particularly advantageous to divide the ring, i.e. to make it up of several ring arch sections (not shown separately). Such division can be designed so that the components forming the bushing can be replaced without the need to remove the plunger.

[0098] FIG. 10 shows a fourth embodiment of the present invention as well as a fifth embodiment.

[0099] What has been said above regarding the first to third embodiments also applies to the illustrated embodiments, since these illustrated embodiments are technically and functionally considered to be a combination of the second and third embodiments.

[0100] The upper half of Figure 10 along the longitudinal axis shows a fourth embodiment. The bushing 9 is again multi-part, preferably consisting of the number of rings Ri1 to Rin mentioned above, but in this case each ring is elastically mounted on its outer periphery by either an elastomeric compound cast onto it, or by vulcanizing an in-situ formed rubber ring, or by being inserted into a common elastomeric sleeve formed as a separate part, as explained in relation to the second embodiment above.

[0101] In this way, each ring is movable at least to a large extent independently of the other rings, which allows for particularly good self-adjustment of the seal gap shape.

[0102] The lower half of FIG. 10 along the central longitudinal axis shows a fifth embodiment.

[0103] A feature in this case is that each ring has its own dedicated bearing sleeve, which can be configured, for example, as an O-ring, an X-ring, or other standard component (if the necessary grooves are present). In this case, the associated ring has clearance from the housing on both sides of the bearing sleeve. This allows for particularly high mobility or self-adjustment.

[0104] FIG. 11 shows the bushing 9 in detail, highlighting the angled chamfer. As shown, this chamfer on the high-pressure side consists of a steeper first portion FA1 on the side facing the high-pressure chamber. This first portion includes a chamfer angle Alpha1 of 45° or approximately 45° relative to the longitudinal axis of the bushing. This first portion is joined to a second chamfer portion FA2 on the side facing the sealing gap, which has a flatter chamfer angle Alpha2. The second chamfer is preferably narrow enough to prevent or only allow limited penetration of solid particles. This reduces the load on the annular gap caused by solid particles.

[0105] Such a chamfered portion may also be provided on the low pressure side.

[0106] Notwithstanding the above claims, as an option to the high-pressure homogenizer according to the independent claim, protection may be claimed for a homogenizer that does not have a low-pressure chamber surrounding at least one plunger shaft, possibly in conjunction with one or more of the dependent claims.

[0107] Additionally, protection is claimed for methods implemented in the high pressure homogenizers described in the context of this disclosure that optionally use a plunger pump with an annular gap seal. [Explanation of symbols]

[0108] 1 High-pressure homogenizer 2. High-Pressure Chamber 3 Homogenization Unit 4 Plunger Pump 5 plunger 6 Plunger shaft 7 Low-pressure chamber 8 High-pressure seal 9. Bush 10 Drive side end face of bush 11 Inner side of bush 12 Drive piston 13 Universal Coupling 14 Drive end face of plunger 15 Plunger side end face of drive piston 16 Inlet / outlet / pipe to low pressure chamber 17 Housing portion surrounding low pressure chamber 18 Housing portion surrounding the high-pressure chamber 19 Connecting pipe between low pressure chambers 20 Locating pin 21 Fixing screw holes 22 Gasket 23 End face of plunger in high pressure chamber 24 Retaining bush 25 Low-pressure seal device 26 Housing cover 27 Housing cover fixing screw 28 Product storage container 29 Supply Pump 30 Inlet valve 31 Outlet valve 32 Housing portion surrounding the high-pressure chamber (schematic diagram) 33 Product collection container 34 Threads of universal coupling forming axis of rotation 35 Coupling part on plunger side 36 Coupling intermediate piece 37 Coupling part on the drive piston side 38 Threads on universal couplings for applying clamping force 39 Universal coupling receiving opening 40 Bush Bevel 41 Chamfered part 42 Bearing sleeve L length S Annular gap height / Throttle gap A-A cross section B-B cross section line D-D Section line r radius LA Longitudinal central axis Ri1‐Rin ring Alpha1 chamfer angle Alpha2 chamfer angle FA1 First chamfered part FA2 Second chamfered part B Bellows F1 Connection F2 connection

Claims

1. A high-pressure homogenizer for flowable substances filled with particles, comprising: a high-pressure chamber (2); a homogenization unit (3) fluidly connected downstream of the high-pressure chamber (2) for turbulently depressurizing the fluid to be homogenized in the high-pressure chamber (2), the fluid being previously pressurized in the high-pressure chamber (2) to a pressure of more than 500 bar; a plunger pump (4) assigned to the homogenization unit (3) and having a plunger (5) for pressurizing the high-pressure chamber (2); and a low-pressure chamber (7) surrounding a plunger shaft (6) and adapted to cool the plunger (5), the low-pressure chamber (7) having an operating pressure PN of PN≦25 bar, the low-pressure chamber (7) and the high-pressure chamber (2) being separated from each other by a seal (8) through which the plunger (5) passes, the seal (8) is a throttle gap formed between the plunger shaft (6) and a bushing (9) that does not contact the plunger shaft (6), and the length (L) and the radial annular gap height (S) of the throttle gap (8) satisfy S / L≦0.0015; 1. A high-pressure homogenizer for flowable substances, characterized in that an end face of the bush (9) transitions to its inner side via a chamfered portion (41) on a side facing the high-pressure chamber (2), the chamfered portion (41) being composed of a first chamfered portion (FA1) which is steeper on the side facing the high-pressure chamber (2), the first chamfered portion (FA1) comprising a chamfer angle (Alpha1) of approximately 45° relative to a longitudinal axis of the bush (9), the first chamfered portion (FA1) being joined on the side facing the throttle gap by a second chamfered portion (FA2) having a flatter chamfer angle (Alpha2) comprising a chamfer angle (Alpha2) of less than or equal to 30°.

2. 2. A high pressure homogenizer (1) for flowable substances according to claim 1, characterized in that the cylindrical length (L) of the throttle gap is at least 2 / 3 of the diameter of the plunger (5).

3. 3. A high-pressure homogenizer (1) for flowable substances according to claim 1 or 2, characterized in that the annular gap height (S) of the throttle gap is at most 0.03 mm.

4. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 3, characterized in that the bush (9) and the plunger (5) are made of materials having different thermal expansion coefficients.

5. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 4, characterized in that the plunger (5) is made of a ceramic material.

6. A high pressure homogenizer (1) for flowable substances according to any one of claims 1 to 5, characterized in that the material of the bush (9) is softer than the material of the plunger (5).

7. 7. A high-pressure homogenizer (1) for flowable substances as claimed in any one of claims 1 to 6, characterized in that the plunger (5) is guided such that the longitudinal axis of the bush (9) and the longitudinal axis of the plunger shaft (6) moving back and forth within the bush (9) are consistently parallel or coaxially aligned, either by the plunger (5) being at the same time a drive piston (12) or by the drive piston (12) and the plunger (5) being fixedly guided in a housing in their connection area.

8. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 7, characterized in that the bush (9) is held substantially stationary in the radial direction in a housing part surrounding the bush (9) and the plunger (5) is connected to the drive piston (12) driving the plunger (5) via a radially flexible coupling which avoids the transmission of a pivoting movement from the drive piston (12) to the plunger (5).

9. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 7, characterized in that the bush (9) is radially movable to a certain extent within a housing part surrounding the bush (9) and the plunger (5) is radially fixedly connected to a drive piston (12) which drives the plunger (5).

10. 9. A high-pressure homogenizer (1) for flowable substances as described in claim 8, characterized in that the drive side end face (14) of the plunger (5) or the end face (15) of the drive piston (12) which transmits the drive pressure to the end face (14) is convexly curved.

11. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 10, characterized in that the bush (9) is made up of a plurality of parts and is made up of rings which are in direct contact with one another and are mounted directly and one after the other.

12. A high-pressure homogenizer (1) for flowable substances according to any one of claims 1 to 11, 1. A high-pressure homogenizer for flowable substances, characterized in that the bush (9) involved in the formation of the throttle gap is mounted so as to float as a whole by at least partially providing a bearing sleeve (42) made of a material which is compressible to a certain degree on the outer periphery of the bush (9), or each ring constituting the bush (9) is mounted so as to float by at least partially providing a bearing sleeve (42) made of a material which is compressible to a certain degree on the outer periphery of the bush (9).

13. A high pressure homogenizer (1) for flowable substances according to any one of claims 1 to 12, characterized in that the outer lateral surface of the bush (9) is spherical rather than ideally cylindrical.

14. A method of using a high pressure homogenizer (1) according to any one of claims 1 to 13, comprising matching the materials of the bushings (9) and the plunger (5) to the fluid to be homogenized such that changes in the throttle gap height (S) in the throttle gap caused by temperature changes in the throttle gap area tend to resist further temperature changes corresponding to said temperature changes.

15. 13. A method of using the high pressure homogenizer (1) according to claim 12 as a component in a high pressure homogenizer system, the high pressure homogenizer system being composed of the high pressure homogenizer (1) and a series of bushes (9) made of different materials, the bushes (9) allowing a user to adjust the high pressure homogenizer (1) within a predetermined operating range so that the thermal change behavior of a gap height (S) formed between the plunger shaft (6) and a first bush of the series of bushes (9) can be adapted to the fluid to be homogenized at a gap height (S) formed between the plunger shaft (6) and a second bush of the series of bushes (9) adjacent to the first bush of the series of bushes (9).

Images