Homogenizing valve

Abstract

A homogenizing valve, with a housing (1) which has a fluid inlet (2) and a fluid outlet (3) and in which a valve body is arranged, is designed in such a way that the valve body consists of a sleeve (4), the wall of which has at least one fluid-open gap (6) closed at both ends and whose flow rate length can be varied by a blocking element (7), whereby the blocking element (7) and the sleeve (4) can be moved relative to one another and the blocking element (7) covers the gap (6) in certain areas.

Description

[0001] DESCRIPTION Homogenizing valve Technical field

[0002] The present invention relates to a homogenizing valve.

[0003] The proposed invention may be used, for example, in emulsification and mixing processes, in particular in the case of multiphase fluids with large flow rate amounts. In this case, emulsions and dispersions are brought to a process-dependent pressure in the range of typically about 50 to 500 bar via high-pressure positive-displacement pumps and pressed through narrow gaps in a valve known as a homogenizing valve.

[0004] During the resulting expansion, the desired comminution of the disperse phase is achieved due to turbulence, pressure gradients and shear. The aim is to have a particle size as small as possible with a narrow particle size distribution and a use of energy as little as possible.

[0005] Homogenization aims at reducing the droplet size of the dispersed phases to such an extent that separation of the two phases within a predetermined storage and use time is reliably prevented.

[0006] The gap height depends on the volume flow of the process fluids and should remain as small as possible in the range of 30 - 50 pm in order to achieve the desired properties. For this reason, so-called multi-gap valves are used for larger volume flows, in which the total flow rate is divided in parallel on single gaps, which are formed by multiple stacked and centred valve discs.

[0007] Background art

[0008] Such multi-gap valves are disclosed, for example, in EP 34675 B1 and US Pat. No. 11 660 180 B2, wherein optimum gap heights of 30-50 pm, in particular 40 pm, are specified, in particular with regard to a lowest possible energy consumption. It also explains therein how an axially limited adjustable, radially flowed-through valve gap is formed by the width of the respective radial valve protrusion and the underside of the valve disc lying above it. A change in the gap height is caused by the deflection of the valve disc lying above it, which is generated by an axially directed actuating force. However, due to the risk of breakage, this is only possible to a limited extent and in a limited region, since the resulting plate bending generates bending stresses that are only tolerated to a small extent reliably by the hard and brittle materials from which the valve elements are made.

[0009] Furthermore, the valve discs require spring elements that are required both for centring the valve discs and for opening the valve gaps to a pressureless circulation or for CIP cleaning (CIP = Cleaning In Place, cleaning without dismantling components).

[0010] Multi-gap valves are used, among other things, in the pharmaceutical and cosmetics industries, as well as in the food industry, for example in the processing of dairy products or fruit juices.

[0011] Multi-gap valves suitable for this purpose are disclosed, inter alia, in US Pat. No. 5 749 650 A, WO 01 / 03818 A1 , WO 01 / 03819 A1 and WO 2012 / 084986 A1. In these constructions, multiple annular valve discs are stacked and configured in such a way that a gap is formed between two valve discs lying on top of one another.

[0012] However, due to their design, the known homogenizing valves have a number of disadvantages that stand in the way of the desired optimised use. This concerns the quality of the homogenized emulsions or dispersions, the reproducibility of the results, the production costs and safety, the service life and the required energy demand.

[0013] A common feature of all known valves for high-pressure homogenization is the height adjustability of the homogenizing gap, wherein a reduction in the gap height serves to generate pressure and, during the subsequent expansion, to create a turbulence zone at the gap outlet, by means of which the desired droplet size reduction of the dispersed phase is brought about. First and foremost, the gap height has a major influence on product quality with otherwise constant process parameters.

[0014] The homogenizing gaps are formed by two end faces of a valve seat and an associated valve. Due to this basic design, there is a general dependence on the manufacturing tolerances that are unavoidable and permissible in industrial production, such as dimensional, shape and position tolerances.

[0015] For example, guide clearances of the valves can lead to a slight obliquity thereof, resulting in a valve gap being not constant over the circumference.

[0016] The same results if the valve surfaces of the valve seats are not formed at right angles to the centre line.

[0017] In practice, a combination of all possibilities which generate all states between a possible maximum and minimum usually occurs. Since the limitation of the manufacturing tolerances is limited for economic reasons, and the optimal gap heights in the range of 30-50 pm are very small, there is a non-negligible influence on the product quality of the emulsions and dispersions in industrial operations.

[0018] The large number of required components not only leads to considerable production costs as well as to an increased susceptibility to faults, which in turn results in an interruption of operation, but also to dimensional and geometric deviations, which on the whole lead to an impairment of product quality.

[0019] In this context, it should be mentioned that tolerance-related deviations from a radially symmetrical flow rate result in asymmetrical pressure fields that, in conjunction with the respective relevant surfaces, generate forces and torques that, for example, cause an inclination of the valve with a maximum and minimum gap height. Here effects are known that generate by feedback high-frequency vibrations with strong sound emission, which can lead to the destruction of components.

[0020] A further, systemic disadvantage of the prior art is the basic principle of known homogenizing valves, that the quality-determining homogenizing gap is height-adjustable or at least partially height-adjustable and is geometrically fixed via at least two valve components with tolerances. Furthermore, through this principle the risk arises that, in the case of air inclusions in the fluid, which are generated, for example, by switching processes or leaks at feed pumps, the compressibility thereof temporarily interrupts the volume flow and the actuating device fully closes the homogenizing gap for a short time. The resulting impact of the valve on the valve seat and the subsequent pressure peak during the subsequent restart of the liquid delivery can lead to considerable damage up to total failure.

[0021] Disclosure of the invention

[0022] In this context, the object of the present invention is to provide a homogenizing valve which overcomes the problems of the prior art cited above.

[0023] In particular, the object of the present invention is to further develop a homogenizing valve of the generic type in such a way that it is structurally simpler and more cost-effective to produce, and its functional reliability is improved.

[0024] This object is achieved by a homogenizing valve with the features of claim 1.

[0025] Compared to the prior art, the new homogenizing valve can be operated with significantly fewer functional parts, while in the case of the aforementioned multi-gap valves, a large number of single independent, parallel-crossed gaps is provided, for example formed by the upper and lower sides of single valve discs.

[0026] According to the invention, however, only one sleeve is inserted into the inside of a housing with at least one fluid-open gap in the wall of the sleeve. Preferably, multiple gaps that are arranged equally spaced from one another are provided, the dimensions of which may be the same, but may also be different.

[0027] The gap may be aligned axially and / or transversely thereto and / or oblique. In any case, the longitudinal boundaries of the gap run parallel to one another, resulting in a constant, non-adjustable gap height, transverse to the longitudinal extension.

[0028] Thereby the variable flow rate is now no longer generated by several guided components with the disadvantages described, but from the constant gap height and the variable flow rate length of the gap. For this purpose, according to the invention, a blocking element is provided, which is moved relative to the sleeve in such a way that, depending on the necessary adaptation to the process parameters of pressure and volume flow, a part of the gap is covered.

[0029] This results in process advantages such as a reliable reproducibility of the homogenization results, an accurate measurement and monitoring possibility of the state of wear via the current position of the blocking element, a high product quality, significant energy savings, a high reliability and a very high efficiency of the homogenization process.

[0030] Examples of manufacturing advantages include simple and error-free assembly, a modular system, and a reduction in the number of parts and as a result thereof a cost-effective production.

[0031] The introduction of the entry region and of the exit region forming the homogenizing gap into the sleeve can take place by means of different methods. For example, by machining through milling or grinding the entry region, by water abrasive blasting or by laser and electron beam cutting. The latter also leads to a hardening of the surface of the edge regions of the gap, which increases its wear resistance.

[0032] The sleeve is preferably made of stainless, martensitic stainless steel alloys, nickel or cobalt-based alloys, and nickel-bonded hard metal.

[0033] Furthermore, by means of the new homogenizing valve, a path control for the blocking element can be used as an alternative to the usual force control according to the prior art, since the actuating path is significantly larger than in the case of a working range of 30 to 50 pm and can therefore be made more simply. If this is used, it opens up the possibility of the parallel operation of several homogenizing valves and the possibility of the defined division into several single volume flows. In order to be able to carry out a pressureless start-up or a CIP cleaning (CIP = Cleaning In Place) at low pressure, homogenizing valves must enable a pressureless circulation, which is ensured in the embodiments according to the prior art by opening the valve gap height or setting a large valve gap height. In the invention, this is achieved by a cross-sectional widening at one end of the gap. During operation, this region is closed by the blocking element.

[0034] Depending on the requirement, the cross-sectional geometry of the gap can be chosen. A cross-sectional contour with parallel gap walls, i.e. gap height remaining radially constant, is conceivable. The cross-sectional contour can be conical with gap walls tapering in the direction of flow or a combination of conical gap in the entry region and adjoining parallel gap walls.

[0035] Further advantageous embodiments are characterized in the dependent claims.

[0036] Brief description of drawings

[0037] Exemplary embodiments of the invention are described below with reference to the attached drawings, wherein:

[0038] - Figure 1 shows an exemplary embodiment of a homogenizing valve according to the invention in longitudinal section;

[0039] - Figure 2 shows a further exemplary embodiment of a homogenizing valve according to the invention, likewise in longitudinal section;

[0040] - Figures 3 and 4 each show a cross-section through a partial section of different variants of the homogenizing valves according to the invention.

[0041] Detailed description of preferred embodiments of the invention

[0042] Figures 1 and 2 each illustrate a homogenizing valve with a housing 1 that has a fluid inlet 2 and a fluid outlet 3.

[0043] According to the invention, a valve body in the form of a sleeve 4, which is smaller than the inside of the housing 1 , is arranged in the housing 1. Arranged in the wall 5 of the sleeve 4 are multiple gaps 6, which run parallel to and at a distance from one another and are axially aligned. At the ends, the gaps 6 are closed, but fluidly open from the inside of the housing 1 towards the inside of the sleeve 4. Each gap 6 has an entry region 16 and an exit region 15, which faces the inside of the sleeve 4 and forms a homogenizing gap.

[0044] The flow rate length of the gaps 6 can be varied by a blocking element 7, which can be moved axially relative to the sleeve 4 by an actuator 8. In the example, the sleeve 4 and the blocking element 7 are cylindrical.

[0045] In this case, the blocking element 7, the diameter of which corresponds to the inner diameter of the tightly abutting sleeve 4, dips into the sleeve 4 while functioning, in accordance with the arrow, wherein the maximum immersion depth can be seen in dashed lines. The ends 9 of the gaps 6 facing the blocking element 7 are widened in order to enable pressureless circulation, for example cleaning flushing.

[0046] The blocking element 7 has two gaskets, namely in the upper region towards the environment, in the lower region towards the fluid outlet 3. This always generates an opening force effect to ensure a fail-safe function. In the lowermost position of the blocking element 7, the gap remains open, so that a full closing of the valve and pressure peaks associated therewith are prevented.

[0047] Figure 1 shows a single-stage homogenizing valve, whereas figure 2 depicts a two-stage homogenizing valve. The second homogenization stage is formed by an axially adjustable plunger 10 with a conical head 11 in cooperation with a fluid outlet 12 of the sleeve 4 adapted thereto, as a result of which, depending on the adjustment of the plunger 10, a circumferential gap 13 whose height is adjustable is formed, through which further homogenization of the fluid takes place.

[0048] Figures 3 and 4 each show a cross-section through the sleeve 4 of the new homogenizing valve. In this case, the gaps 6 in the entry region 16, starting from the outside of the sleeve 4, i.e. from the entrance side of the fluid, are tapered toward the inside of the sleeve 4 and merge into the exit region 15 with parallel gap walls.

[0049] In the example illustrated in figure 3, the gaps 6 are radially aligned with a beam cutting line 14 in the longitudinal axis of the sleeve 4, while figure 4 shows a tangential alignment of two gaps 6 with a common beam cutting line 14 in front of the longitudinal axis of the sleeve 4.

[0050] Figures 1 and 2 reproduce a homogenizing valve in which the gaps 6 are axially aligned, as well as the movement of the blocking element 7, which can be moved in the same direction when the gaps 6 run oblique with respect to the longitudinal axis of the sleeve 4.

[0051] In an arrangement (not illustrated) of the at least one gap 6 in a circumferential region of the sleeve 4, that is to say transversely to the longitudinal axis thereof, the change in the flow rate length of the gap 6 is effected by rotating the sleeve 4 with respect to the blocking element 7, which is fixed with respect thereto, the blocking element 7 tightly abutting on the lateral surface of the sleeve 4.

[0052] In this case, the blocking element 7 has a longitudinal groove in the same direction as the gap 6 of the sleeve 4, which longitudinal groove forms lined up with the gap 6 a correspondingly adjustable fluid passage.

[0053] Reference numeral list

[0054] 1 Housing

[0055] 2 Fluid inlet

[0056] 3 Fluid outlet

[0057] 4 Sleeve

[0058] 5 Wall

[0059] 6 Gap

[0060] 7 Blocking element

[0061] 8 Actuator

[0062] 9 End

[0063] 10 Plunger

[0064] 11 Head

[0065] 12 Outlet Circumferential gap Beam cutting line Exit region Entry region

Claims

CLAIMS1. A homogenizing valve comprising:- a housing (1 ) which has a fluid inlet (2) and a fluid outlet (3) and in which a valve body is arranged;- a blocking element (7), said valve body comprising a sleeve (4) havinga wall with at least one fluid-open gap (6) closed at both ends and whose flow rate length can be varied by said blocking element (7), whereby the blocking element (7) and the sleeve (4) can be moved relative to one another, and the blocking element (7) covers the fluid-open gap (6) in certain areas.

2. The homogenizing valve according to claim 1 , characterized in that the at least one fluid-open gap (6) runs axially, transversely thereto or oblique.

3. The homogenizing valve according to claim 1 or 2, characterized in that opposite walls of the at least one fluid-open gap (6) run parallel to one another.

4. The homogenizing valve according to any one of the preceding claims, characterized in that it comprises multiple axially aligned gaps (6) which are arranged at the same distance from one another.

5. The homogenizing valve according to any one of the preceding claims, characterized in that the blocking element (7) is guided axially movably in the sleeve (4) by an actuator (8).

6. The homogenizing valve according to any one of the preceding claims, characterized in that an end (9) of the at least one fluid-open gap (6) facing the blocking element (7) is widened.

7. The homogenizing valve according to any one of the preceding claims,characterized in that it comprises an axially adjustable plunger (10) which is provided opposite to the blocking element (7), said axially adjustable plunger (10) having a conical head (11 ) which corresponds to an end of an outlet (12) of the sleeve (4) adapted thereto, forming a circumferential gap (13).

8. The homogenizing valve according to any one of the preceding claims, characterized in that the at least one fluid-open gap (6), starting from the outside of the sleeve (4), tapers in an entry region (16) towards the inside of the sleeve (4) and merges into an exit region (15) with parallel gap walls.

9. The homogenizing valve according to any one of the preceding claims, characterized in that it comprises multiple gaps (6) which are aligned radially in a direction of flow.

10. The homogenizing valve according to any one of the preceding claims, characterized in that it comprises two gaps (6) which are aligned tangentially in opposed directions, with a beam cutting line (14) in front of the longitudinal axis of the sleeve (4).11 . The homogenizing valve according to any one of the preceding claims, characterized in that, when the at least one fluid-open gap (6) is arranged in the circumferential direction of the sleeve (4), the blocking element (7) can be rotated with respect to the sleeve (4).

12. The homogenizing valve according to claim 11 , wherein said blocking element (7) has a longitudinal groove in the same direction of the at least one fluid-open gap (6) of the sleeve (4), said longitudinal groove forming an adjustable fluid passage which is lined up with said at least one fluidopen gap (6).

13. The homogenizing valve according to any one of the preceding claims, further comprising two gaskets, respectively in an upper region towards an environment, and in a lower region towards the fluid outlet (3).

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