Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
  • F15D1/00—Influencing flow of fluids
  • F15D1/02—Influencing flow of fluids in pipes or conduits

Definitions

• the invention relates to a method for influencing the rheological properties of a fluid according to the preamble of claim 1.
• Influencing the rheological properties of product masses e.g. viscous fluids but also viscoelastic pastes or elastomer mixtures, or also the "rheological properties" of fluidized bulk goods, can e.g. can be achieved by shear, elongation or fluidization.
• the invention is therefore based on the object of overcoming these disadvantages and inadequacies of the known methods and systems for processing fitable products and, in particular, of improving the rheological properties of such products.
• the rheological properties of at least part of the fluid can be influenced in a targeted manner by at least a part of the fluid elements forming the fluid being excited to vibrate.
• a reduction in the internal fluid friction as well as the external fluid friction at fluid / machine interfaces can be achieved. This makes it possible to reduce the energy input into the fluid, which on the one hand significantly increases the service life of a machine and on the other hand enables the construction of machines with larger dimensions without reaching the limits of the power / output that can be achieved by the machine and its limits Stability bumps. In other words, an increase in throughput can be achieved with the same delivery rate.
• the vibration excitation also acts on the fluid with which the actual rheological properties are changed to effective rheological properties. Instead of attempting to capture and control the complex rheological properties of a real fluid, it has proven advantageous to change the real rheological properties by applying vibrations to the fluid elements forming the fluid to effective rheological properties that are easier to handle let as the underlying real rheological properties. In other words, the fluid is "artificially" changed by the vibrations introduced in such a way that it is easier to control, at least in this changed state.
• Fluid elements are preferably excited to vibrate in very specific areas of the fluid. For example, increased dwell times of the fluid in niches and dead volumes can be reduced by targeted vibration excitation or the Friction at wall / fluid interfaces, in particular in lines for fluid transport, can be reduced. This results in a reduction in the residence time spectrum of the fluid treated in the machine or transported in the line and leads to the material and energy savings already mentioned.
• the fluid can be a mixture of at least one gaseous, liquid or solid phase, each phase consisting of different phase elements (finite elements).
• the phase elements can in particular be particles, bubbles or agglomerates, so that the fluid is a suspension, an emulsion, a fluidized powder or powder mixture, a foam or foam mixture or a colloid or colloid mixture.
• the fluid can also be a polymer or a polymer mixture.
• the various types of elements of the fluid are expediently selectively excited to vibrate.
• Problem zones can be worked on locally and / or globally.
• Such problem areas are e.g. Nozzles or dead volumes.
• a high pressure gradient which can be significantly reduced when the fluid is used with the effective rheological properties, that is to say changed by vibration.
• dead volumes in the fluid to be processed can be revitalized by targeted vibration influencing.
• the selective vibration excitation preferably takes place on an entire group of elements or a plurality of groups of elements.
• the vibration is excited by at least one source for mechanical vibrations that acts on the fluid.
• This enables different vibrations with different amplitudes and different frequencies to be entered into the fluid.
• extremely large vibration amplitudes in the fluid can be achieved in selected areas by superimposing the various vibrations.
• the vibrations can be generated partly pneumatically and / or partly hydraulically.
• a mechanical oscillation by shock excitation in particular by several successive shock excitations, is also advantageous.
• the sudden shock excitation corresponds to a superposition of many different vibration frequencies, so that shock excitation can excite resonance vibrations over a very large frequency range, which can be maintained over a long period of time by successive shock excitations.
• the source of mechanical vibrations is the at least one interface of the plant or machine part. In this way, fewer parts are required, and the fluid can still be influenced in a targeted manner.
• the at least one vibrating interface preferably has at least one vibration component in the tangential plane of the wall / fluid interface.
• the fluid / wall friction can be reduced or controlled by creating a targeted sliding / sliding effect. Any necessary change or adaptation of the wall material to special fluids is therefore unnecessary. Instead, a controllable coefficient of friction between the wall and the fluid can be produced by selecting the frequency and / or amplitude of the tangential vibration component.
• the at least one interface has a vibration component normal to the tangential plane of the wall / fluid interface.
• This normal component of the interfacial vibration allows a particularly large amount of vibration energy to be introduced into the fluid volume.
• a combination of the tangential and normal vibration components of the wall / fluid interface can thus be used to generate an extremely targeted and specific supply of vibration energy into the fluid.
• the vibration is excited by at least one source for electromagnetic waves which act on the fluid.
• the electromagnetic vibration excitation has a gentler influence on the fluid, the vibration excitation taking place predominantly on the molecular level or on the level of small agglomerates if they are temporary or permanent dipoles such as water molecules or surfactant molecules when using multiple sources for Electromagnetic waves can also be excited with several frequencies or frequency ranges, and different particles with a dipole character can be excited to rotational vibrations in the fluid.
• the fluid / wall interface in contact with the fluid can be a wall of a line intended for the transport of the fluid or else a surface of a processing element of a machine that processes the fluid.
• it can be an interface which, apart from its oscillatory movement, does not carry out any further movement. This is e.g. the case with a static mixer.
• the interface can also perform at least one further movement in addition to its oscillatory movement, such as a translation and / or rotation.
• the wall friction is reduced due to the vibration of the interface. This is particularly advantageous with pipelines when transporting viscous fluids or with dynamic mixers.
• the fluid flow can be a drag flow, a pressure flow, a combination of drag and pressure flow, an expansion flow, a shear flow and also a cavitation flow.
• a combination of expansion flow and vibration is particularly advantageous.
• the disagglomeration caused by the expansion flow is supported by the vibration of the agglomerates.
• This synergy can be particularly advantageous in a vibrating Realize the slit mill by superimposing stretch and vibration.
• the superimposed vibration also proves to be extremely useful in deagglomeration by means of shear flow, since this vibration counteracts segregation of the deagglomerated particles along various flow layers in laminar-flowing areas and thus prevents the agglomerated particles from being re-agglomerated.
• the vibration excitation takes place in selected frequencies or frequency ranges, in particular in combination with vibration excitation with selected amplitudes or amplitude ranges.
• This allows targeted and selective action on various phase elements, such as Particles, bubbles, aggregates, etc. according to size, type, composition, shape etc. are brought about.
• the selected excitation frequencies and amplitudes can also be adapted to the respective degree of processing of the fluid, that is to say the respective state of the phase elements. For example, with increasing deagglomeration of the particles, the increasingly smaller particles are further excited with increasing frequencies.
• the vibration excitation by successive impacts is particularly advantageous here, too, since the impacts introduce a wide frequency spectrum into the fluid.
• Successive strikes are preferably carried out, each separated by a time interval of constant length. In this way, it is ensured that after the oscillations of phase elements caused by a blow have subsided, the same vibrations on the phase elements are repeatedly excited with a large initial amplitude.
• the successive beats can preferably also be separated from one another by a time interval of stochastic length. This prevents periodic behavior from being impressed on the fluid from the outside. Rather, the vibration excitation, which is caused by the beats which follow one another at stochastic time intervals, prevents the fluid flow can assume a steady state. This is particularly advantageous in order to prevent segregation processes.
• the successive beats can also be separated from one another by time intervals, the lengths of which are normally distributed. In this way, a kind of compromise can be reached between the procedure with time intervals of constant length and the procedure with time intervals of purely stochastic length.
• the selected frequencies or frequency ranges of the excitation vibration are expediently assigned natural frequencies of certain types of phase elements assigned to certain vibration modes.
• phase elements of a certain type, size, composition or shape can be targeted in this way.
• At least one surface-active substance can also be added to the fluid in the method according to the invention. This allows e.g. stabilize a deagglomeration of phase elements caused by the vibration excitation. It proves to be particularly advantageous if at least one specific surface-active substance is added to the fluid for different phase elements of the fluid.
• a wide range of processes can be optimized through the use of different vibrational excitations and various surface-active substances that are coordinated with the process at different times and locations.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Apparatuses For Generation Of Mechanical Vibrations (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

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• 2001
  • 2001-07-05 DE DE2001132069 patent/DE10132069A1/de not_active Withdrawn
• 2002
  • 2002-02-22 WO PCT/CH2002/000103 patent/WO2003004882A1/de not_active Application Discontinuation
  • 2002-02-22 RU RU2004103186/06A patent/RU2301916C2/ru not_active IP Right Cessation
  • 2002-02-22 CN CNB02813365XA patent/CN100378349C/zh not_active Expired - Fee Related
  • 2002-02-22 MX MXPA03011880A patent/MXPA03011880A/es active IP Right Grant
  • 2002-02-22 EP EP02711732A patent/EP1404979A1/de not_active Ceased

Non-Patent Citations (1)

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