RU2081689C1 - Mixer - Google Patents

Abstract

FIELD: mixers. SUBSTANCE: the offered mixer has cylindrical body with axial channel for introduction of the first compound, pipes with bent ends for introduction of the second compound installed for reciprocation in body side holes, and cavitators installed before pipes and made, for instance, in form of truncated cones directed with their small bases toward the material flow and having through holes. EFFECT: higher efficiency. 9 cl, 1 dwg

Description

 The invention relates to the field of instrumentation and can be used in light, chemical and other industries for mixing, emulsifying and homogenizing liquid and gaseous multicomponent systems, as well as for dispersing solid particles in a liquid.

 Known built-in static mixer formed by a cylindrical body, in the cavity of which are placed flat plates, blades and blades of complex shape (see US patent N 4 461 579, CL BO1F 5/00, 1984).

 However, this mixer is quite complicated, and, in addition, does not provide a high degree of homogenization, since the mixed components enter it simultaneously. Moreover, for efficient mixing, either a preparatory mixing step or multiple recirculation is required.

 In order to eliminate the above drawbacks, mixers were developed in which one of the components was fed into the cavitation zone or, in any case, into the turbulent flow zone of the second component (see, for example, UK patent N 2 022 430, class BO1F 5/00, 1979 ) This mixer contains a housing with a longitudinal nozzle of the input of the first component and inclined nozzles of the input of the second component.

 Closest to the proposed is a mixer containing a cylindrical body with an axial channel for input of the first component and side channels for the input of the second component of the mixture, located at a certain acute angle to the axis of the body (see US patent 4,474,477, class B O1 F 5/00 , 1984).

 The disadvantages of mixers of this type include low mixing efficiency, due to both the absence of swirls and the location of the nozzles, and a significant dependence of mixing efficiency on the composition of the mixture, so that a mixer configured for a certain flow rate of components is unsuitable for operation with a changed flow rate, which limits the range its use, since for most applications the composition of the mixture is variable.

 Thus, the technical result expected from the use of the invention is to increase the mixing efficiency in a wide range of possible mixture compositions.

 This result is achieved by the fact that the known mixer containing a cylindrical body with an axial channel for input of the first component and side channels for input of the second component of the mixture is equipped with swirls, input channels of the second component are made in the form of tubes and a curved end located in the side openings of the body, while swirls placed in the cavity of the housing coaxially with it, and the curved ends of the tubes are located behind the corresponding swirlers in the cavitation zone.

 In addition, the tubes can be installed in the side openings of the housing with the possibility of reciprocating and / or rotational fixed movement.

 It is also advisable that the tubes are connected by a common input pipe of the second component with the flow direction opposite to the flow direction in the mixer.

 It is recommended that the angle between the axis of the tube and its curved end be 26-34 degrees.

 In addition, the angle of rotation of the tube may lie in the range of 15-25 degrees.

In this case, the relative displacement of the end of the tube can be 20-70%
In addition, the swirlers can be made with through holes, and the cross-sectional area of the previous swirl exceeds the largest cross-sectional area of the subsequent.

 It is also advisable that the relative displacement and angle of rotation of the tube located behind the previous swirler are respectively larger and smaller than the corresponding values for the tube located after the subsequent swirler.

 In this case, the signs of the relative displacements and rotation angles of the tubes located behind adjacent swirlers may be different.

 In addition, part of the swirls can be made with through holes, while swirls with holes and without them can be placed alternately.

 In this case, the relative displacement and rotation angle of the tubes located behind the swirlers with holes are correspondingly smaller and larger than the same values for tubes placed behind the swirls without holes.

And finally, the relative displacement and the angle of rotation of the tubes can be determined from the relations
L = (r + KA) / Gv, a V / CA,
where: L, a relative displacement and angle of rotation of the tube, respectively;
A content of the most viscous component in the mixture;
V consumption of the least viscous component of the mixture;
r, K, G, C constants.

 The drawing shows a longitudinal section of a mixer.

 The mixer comprises a cylindrical body 1 with an inlet channel (fitting) 2 and an outlet channel 3. In the cavity of the body 1, swirlers 4 are installed, behind which tubes 5 with a curved end are placed. The swirlers 4 can be made with through holes 6. The tubes 5 are installed in the holes 7 of the housing.

 Channels 2, 3 can be made conical, respectively tapering and expanding along the flow. In the cavity of the housing 1 there can also be conical sections (diffusers and confusers), which, together with the swirlers 4, provide the appearance of cavitation zones, i.e. zones in which during the use of the mixer a cavitation cavity develops, located behind the corresponding swirler. In the simplest case, the volume obtained as a result of the symmetric transformation of the swirler with respect to the plane of its base can be considered such a zone.

 In the proposed mixer, both conical swirlers and swirls in the form of a prism, pyramid, hemisphere, etc. can be used.

 To install the tubes 5 with the possibility of a fixed movement, i.e. moving in the process of setting up the mixer and fixing in the process of its operation, you can use the sliding fit of the tubes 5 in the holes 7 or thread, preferably with a large pitch. Can be used and automatic mechanisms for axial movement and rotation of the tubes 5 depending on the flow rate and viscosity of the medium. For this purpose, the flow sensors of the most and least viscous components of the mixture can be introduced into the mixer, the outputs of which are connected to the inputs of the processing unit, the outputs of which are connected to the corresponding nodes for adjusting the position of the tubes 5. The algorithm of the processing unit is set by the above ratios, and the constants included in them are determined experimentally for each tube 5 by minimizing the number of recirculations necessary to achieve a certain degree of homogenization of the mixture at the outlet of channel 3. The displacement cutting 5 and the angles of rotation can be set and the same for all tubes.

 The initial position of the tube 5 is considered to be when the slice of its curved end touches the center of the base of the swirl 4, i.e. the end of the tube is on the axis of the housing and lies in the plane of FIG. 1. The value of the relative displacement is defined as the ratio of the displacement of the tube 5 to the inner radius of the housing 1. The sign of displacement is determined arbitrarily, for example, lifting and turning counterclockwise can have a plus sign.

 The tubes 5 can be connected by a common input pipe of the second component (not shown in the drawing), i.e. are consecutive branches of this branch pipe. In this case, the tube 5, located behind the last swirler 4, is the first along the flow of the second component.

 The mixer operates as follows. The main flow of the medium to be treated (the first component of the mixture, which can also be a pre-prepared mixture of substances) is fed into the cavity of the housing 1 through the channel 2. When the swirler 4 passes through the flow, especially if there are diffusers and confusers in the housing cavity, cavitation cavities are formed behind them in which intensive crushing and mixing of the components of the mixture occurs. The second component (a pure substance or some mixture of components) is supplied through tubes 5 directly to the cavitation zone, which contributes to more intensive mixing. A further increase in the degree of homogenization is facilitated by the selection of the optimal positions of the tubes 5 when processing a particular mixture.

 It should also be noted that compliance with the above conditions and restrictions imposed on the location of the tubes 5 can be combined with their installation with the possibility of a fixed adjustment bias and rotation. For example, the mixer can be set within the specified limits, which are structurally expressed as axial displacement and tube rotation limiters 5. And, conversely, the above conditions and restrictions can be observed during the setup process.

 For example, a three-stage mixer with swirls in the form of a truncated cone was tested. Water was supplied through channel 2, and emulsol in the amount of 4 mass. by tubes 5. As a result, it was found that the minimum degree of recirculation equal to unity is achieved by using a tube bent at an angle of 30 degrees, rotated by 20 degrees and shifted by 3-40. Such an experiment allows us to determine the constants.

 Further studies showed that outside the above ranges, the mixing efficiency noticeably decreases (2-2.5) times. This means that the introduction of one of the components directly into the cavitation zone and the optimal choice of the injection point within this zone (due to the above conditions and ratios or due to the individual settings of the mixer) can significantly increase the efficiency of the mixer and use it for processing mixtures in a wide range of compositions.

Claims (9)

 1. A mixer comprising a cylindrical body with an axial channel for introducing the first component, tubes for introducing the second component of the mixture located in the side openings of the body, and cavitators placed in series coaxially in the cavity of the body, characterized in that the tubes are made with curved ends and are located behind the cavitators in the direction of flow of the mixture.  2. The mixer according to claim 1, characterized in that the tubes are mounted with the possibility of reciprocating movement and / or rotation around its axis. 3. The mixer according to claim 1, characterized in that the angle between the axis of the tube and its curved end is 26 34 ^o . 4. The mixer according to paragraphs. 1 and 2, characterized in that the tubes are mounted with the possibility of rotation of 15 25 ^o .  5. The mixer according to paragraphs. 1 to 4, characterized in that the cavitators are made in the form of truncated cones, with a smaller base directed towards the flow and having through holes.  6. The mixer according to paragraphs. 1 to 4, characterized in that the cavitators are made in the form of truncated cones with a smaller base directed towards the flow, and even of them are made with through holes, and the odd ones are solid. 7. The mixer according to claims 1 to 6, characterized in that the relative displacement and the angle of rotation of the tubes are determined from the expressions
L (r + kA) GV;
a V / CA,
where L and a are the relative displacement and angle of rotation of the tube, respectively;
A content of the most viscous component;
V consumption of the least viscous component;
r, k, G, C constants.  8. The mixer according to claims 1, 2, 6 and 7, characterized in that the directions of relative displacement and rotation of the tubes located behind adjacent cavitators are opposite.  9. The mixer according to claims 1, 2, 7 and 8, characterized in that the values of the relative displacement and the angle of rotation of the tubes located behind the cavitators with holes are respectively larger and smaller than for tubes placed behind solid cavitators.