RO137817A0 - Mixing system with variable-geometry injection nozzles - Google Patents

Abstract

The invention relates to a mixing system with variable-geometry injection nozzles, mixing that can be performed continuously and in mass percentage adjustable within a certain value range. According to the invention, the mixing system together with the associated process for a good operation thereof, consists of a series of nozzles with variable geometry placed in an aligned way on a fixed support (4) wherethrough the minority gas flows and an outer body (1) at the end of which a majority gas is introduced, each nozzle set with variable geometry being accompanied, at a certain distance, by a baffle screen, the nozzles having the ends with variable geometry actuated from outside, by means of some rods (3) and a linear guide system (2) which may be actuated manually or automatically by means of a wheel, the components of the mixing system being arranged in a certain succession and configuration which, upon actuation by an actuating element (8) and an outer jacket (7) moving horizontally left-right, said movement increases or decreases the space between the interior lobes (6) and the exterior lobes (5) of the nozzles, simultaneously allowing the human operator to set, automatically or manually, certain mixing ratios.

Description

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Patent application of _ _No .............

Date of deposit............

Mixing system with variable injection nozzle geometry

Introduction

In the wake of the fossil fuel crisis and the adoption of hydrogen as a new energy vector, the European methane gas market has begun to be under pressure to produce mixtures of methane gas with hydrogen and to use these mixtures as substitutes for pure methane gas . It is anticipated that even mixtures of several gaseous substances, including several types of gaseous hydrocarbons, are miscible in certain proportions·

Due to these requirements, in the last period of time intensive efforts are also being made for the development of new types of automated installations to perform the mixing but also the control of the mixing from the point of view of volumetric/mass percentages. Both the production and the transport of these new types of mixtures to the final consumer are considered by the manufacturers of equipment and electrical household goods, together with the suppliers and companies that install equipment in the field of distribution and use of methane gas.

As a desirable already considered normal, for modern society, we want the miniaturization and efficiency of those already existing systems, the decrease of their specific technological consumptions, the maintenance of the mixture state of the constituent components until the moment of use as well as the finding of new models, solutions and analytical methods performance for measuring, performing quickly and in adjustable proportions, but also for controlling the mixture that you want to achieve. Intense efforts are dedicated to maintaining quality and safety standards both for the stage of mixture formation and for the stage of distribution to the end user.

Problems

Operation of existing gas distribution systems including pipes, pressure regulators, safety elements, burners, stoves, power plants, etc. with the new types of mixtures, containing a higher or lower proportion of hydrogen, safely requires great technical attention.

The present invention supports this objective, solving the problem of the controlled introduction of predetermined ratios of flow rates of gaseous components, to be mixed. Depending on the final application, with the help of this invention, the desired mixtures will be able to be modified and achieved in various percentage ratios.

RO 137817 AO

The operating principle of this device and mixing system is based on measuring, controlling and forcing the flow of the components of the future mixture through a device, with variable geometry, which is the subject of the present invention.

Presentation of the invention

By continuously injecting one of the components into the other, also called the majority component, through a sequence of holes drilled in the walls of the inner element of the mixer, holes that have nozzles with variable geometry at the top, and determining the progressive forced passage of the mixture thus formed through a sequence of deflector screens with an approximately circular shape, provided with slots arranged successively, in opposition, which also play a role in determining the change of flow direction, the desired mixture is homogenized.

Figure 1 shows a section through the inside of the mixer assembly, along with the positioning of the nozzles and the guide system.

Figure 1. Variable geometry mixer assembly

The mixer consists of an outer jacket, called the Mixer Body (1), a Linear Guide System (2) for supporting and assembling the actuation rods, Actuation Rods (3) from the outside for making the left-right movement, movement that it changes the geometry of the exit holes in the nozzle, together with the elastic sealing elements on the outside. The introduction of the majority gas is done from the outside and the minority gas, the flow of which is controlled, by changing the nozzles with variable geometry, is done through the inside of the mixer body.

Figure 2. Components of the variable geometry nozzle

Component parts for variable geometry nozzles

Fixed support with petal guide structure (4)

- Outer petals (6)

Inner Petals (5)

The outer sleeve to support and guide the petals (7).

Actuator (8)

Bushing with limiter

RO 137817 AO

The operating mode of the nozzles with variable geometry is based on the left-right movement of the outer jacket (7) by means of the actuating element (8), which supports the outer petals (6) and the inner petals (5) in pairs, and which through the relative movement with respect to the fixed support provided with a guide structure (4), moves in a conjugate pair, moving one over the other thus changing the geometry of the gas flow section.

In order to achieve the mixture in different proportions and to maintain these chosen values in a stable way, it is necessary that one of the components can be introduced in an adjustable way, in relation to the main component. There are various systems to ensure the necessary pressure for the elements/gases/fluids to be mixed, to control the existence of these components and to eliminate the risk of running out of one of the components if the mixture is not achieved.

Actuation of the flow regulation system by changing the geometry of the injection nozzles can be done both manually and automatically, by the manual or automatic actuation from the outside of a wheel that is able to transmit the movement inside the mixer body by means of rods.

The general flow of the mixture, which is a different element from the proportion in which the mixture will be obtained, can be measured and adjusted automatically, with the help of mass transducers, in other words by controlling the masses of the components that enter the structure of the mixture.

The execution element, the wheel located outside the mixer body, can be actuated both electrically and pneumatically, by a tap or by a motor, the actuation configuration can be chosen according to the specific elements available to the user.

The dimensioning of the execution elements, their component parts together with the type of adjustment characteristics is presented in the specialized literature [1-4] and can be done, in a simplified way, using various flow characterization relationships. The system we propose presents a very low pressure drop, being able to be used in applications where safety conditions require low working pressures and the requirements related to maintaining the ratio of the constituent gaseous components is not very restrictive.

By establishing one of the components of the mixture as the main component and choosing their mixing ratio, specific constructive constants can be determined for a possible automatic control element as well as the characteristic parameters of a loop for adjusting a mixture flow rate.

RO 137817 AO

The general principle of measuring fluid flows, therefore also of gas flows, is based on a general cascade flow control loop configuration where one of the control elements is constituted as the master element (component) and the other as the slave component ” whose value is implicitly dictated by the master component and the previously set mix ratio. The ratio between the master and the slave component is imposed by the human operator, according to the technological requirements, by establishing and entering these values in the program sequence and by sizing the pneumatic elements of the cascaded control loops.

In the configuration we propose, if it is desired to change the mixing ratio, without changing the pressure of the slave component, it is necessary to change the geometry of the mixing nozzles, which can be done both manually and automatically depending on the type of actuation chosen by the user.

Figure 3. Nozzle with variable geometry in position a) closed" and b)"open"

Stage] of the technique

The specialized literature together with the databases [1-4] presents a diversity of methods for mixing liquid flows, from general mixing methods [5,6] applicable to all fluids to specific methods for fluids with more special characteristics .

The present invention describes a gas mixing device, based on the injection of one gas stream into another, continuously by means of nozzles, the movement of the mixture thus formed passing progressively through a mixing system, according to Figure 1. The flow rate of the secondary component can be modify also by changing the geometry of the nozzles of the injection element not only by varying the gas pressure, for example, this being the most frequently used solution in the technique.

in order to achieve the homogeneity of the mixture, the flow of the mixture is constrained between a number of almost cylindrical baffles, which we called deflector screens, which are successively followed by injection nozzles with variable geometry, which determine the injection of one of the components so that it it is done progressively, the flow profile should be almost identical, and the mixture formed should be uniformly distributed at the exit from the sequence of chicane reinforcements.

RO 137817 AO

Benefits

The problem that the present invention solves is the modification of the flow rate or the percentage of a component, liquid or gaseous, to be introduced into a mixture stream, in an adjustable way, with the help of nozzles with variable geometry. Another, more expensive method could rely on the existence of high pressure and by constraining the flow through a nozzle-adjustment system.

Conclusion

The current situation, in the relevant industries, such as that of supplying homes with mixtures of hydrogen and natural gas, in order to reduce the carbon footprint, consists of mixing volumes, a process that can be carried out in continuous flow, through the introduction of one fluid into another and presupposes the existence of a pressure difference or the deliberate introduction of a pressure drop. in this configuration that we propose, the resulting product can also be obtained if there are no large pressure differences, which is an advantage from the point of view of operational safety, by changing the geometry of the injection nozzles. The homogeneity of the mixture is achieved by successive introduction and by changing the flow direction of the progressively formed mixture.

RO 137817 AO

BIBLIOGRAPHY

[1] V. Marinoiu, I. Poschina, M. Stoica, Adjusting valves, Technical Publishing House, Bucharest, 1980.

[2] US Patent 5083872

[3] US Patent 6517232

[4] US Patent 3973759

[5] US Patent 4571092

[6] US Patent 6036357

Claims (2)

RO 137817 AO CLAIMS: 1. Mixing system with variable geometry injection nozzles, characterized by the fact that it includes an outer shell called Mixing Body (1) and a number of nozzles with variable internal injection geometry, at least two, these being arranged aligned on a support, having holes drilled in an orderly sequence, with heads of variable geometry, actuated from the outside with a wheel and with the help of actuation rods (3) guided with a linear guide system (2), through a sealed system with a metal tube bellows type that allows horizontal left-right movement to prevent a possible blockage, each set of holes being accompanied at a certain distance by a circular deflector screen corresponding to the configuration provided with a slot that constitutes a series of obstacles for changing direction of the flow of the gas mixture, screens that also allow the nozzles with variable geometry to be actuated from the outside, thus forming a common assembly. 2. A variable geometry mixing system of injection nozzles characterized in that it includes a number of individual variable geometry nozzles, presented and composed according to point 1, which are ordered and connected in a sequence and which by actuation from the outside with with the help of the linear guide system (2) and the actuation rods (3), by moving left and right it acts on the actuation element (8), which through the outer jacket (7) and the fixed support with the guide structure of the petals (4 ) increases or decreases the space between the inner petals (6) and the one between the outer petals (5), in this way presenting the gas flowing between the petals with a variable geometry which, together with the related actuation system, necessary to create multicomponent mixtures, constitutes a whole.