Static mixing Applications

Very many commercial scale applications are efficiently handled with in-line static mixing equipment. Other in-line devices are also used, but the range of applications is less broad. For the purpose of the applications discussed in this section, we are referring primarily to static mixing applications, but recognizing that in some specific cases, other in-line devices may also be employed. 

KOCH Makes Static Mixing Elements For Every Application... 

Rupture disk, 455 Safety relief valves, 454, 467, 481 Specifications, centrifugal pumps, 209 Spray nozzle particle size, 225 Standards and Codes, 31, 32, 33 Static electricity, 536 Static mixing, 332 Applications, 336 Calculations, 337, 338 Materials of construction, 337 Principles of operation, 335 Type of equipment 334-338... 

M 31] [P 28] The time evolution of the flow patterns in the cross-shaped micro mixer with two static mixing elements was monitored by simulation at time intervals of 50,150, 500 ps and 1 ms after application of pressure [71]. In addition to seeing the evolution of the swirling patterns, it was concluded from this analysis that at 500 ps a nearly homogeneous distribution of the mass fractions is given and at 1 ms this is indeed completed. Hence the theoretical mixing time of the mixer may be below 1 ms. 

Often, to prepare for work requiring only a small amount of material, it is convenient to draw the appropriate weights or volumes of the two components from the containers into a suitable disposable cup, then to mix and apply to the substrates by a method appropriate for the viscosity of the mixture. If the scale warrants it is preferable to use application equipment designed for the purpose, in which the components may be extruded as necessary from twin reservoirs through a suitable static mixing nozzle and then to the substrate. It is possible to obtain for this work applicator guns with dual pistons, operated either by hand or by pneumatic pressure. Alternatively, for production on a very large... 

The static mixer presents an alternative to the more traditional agitated vessel. It differs from the mixing vessel in that it is used in continuous processes although it is possible that a static mixer could be incorporated in a batch mixing operation. The static mixer has only been available commercially for a relatively short time but has already been used in a large number of mixing applications. 

There is a wide range of applications of static mixing equipment. Most of the areas traditionally served by agitated vessels seem to have been considered, including various combinations of gases, liquids and solids. The range of applications and industries is now so extensive that there seems no point in... 

One more use of a breaker plate is as a static mixer. Mixing is necessary to produce the homogeneity required in the melt. Several designs allow the breaker plate to serve its conventional functions while also creating flow dynamics that improve the level of mixing in the melt. These devices can be stacked in a series to create various flow fields for different mixing applications. 

There are many more static mixing devices used in the polymer processing industry in fact, the number is so large that it is not possible to list them all. Two characteristics are of critical importance in application of any static mixing device in actual extrusion operations. The first one, obviously, is the mixing capacity. The second one is the resistance that the static mixer offers to flow, i. e., the pressure drop along the static mixer. 

It should be remembered that static mixing devices can also be quite effective in distributive mixing capacity see Section 7.7.2. Thus, if distributive mixing is required, one should consider application of a static mixing device. 

It is not acceptable to use in-line static mixing alone for dilution of emulsion polymers. However, in-line static mixing can be employed for blending secondary dilution water with diluted emulsion product prior to application. Initial dilution of emulsion polymers should be 1 percent or 2 percent by weight. This solution strength ensures proper particle-to-particle interaction during the inversion step, which aids in complete inversion. 

When the flow is laminar, either single or multiphase, there is only one design class option static or motionless mixers. Other pipeline mixing devices described for turbulent flow are not usable for even the simplest mixing applications in the laminar regime. All rely on turbulence and cannot function at low Reynolds numbers. The only alternative technology is in-line dynamic mixers, which include extruders, rotor-stator mixers, and a variety of rotating screw devices. None of these has the benefits of simplicity and the little or no maintenance characteristic of static mixers. In-line mechanical mixers are discussed briefly later in the chapter. 

Tubular Plug Flow Reaction. When the application is a laminar flow tubular reactor, static mixing internals can provide great benefits in terms of... 

Liquid-liquid mixing is common for chemical preparation in various pulp and paper processes. The dilution and makeup of bleaching solutions is done routinely using stirred vessels or static mixers. Applications of this type are discussed in other chapters. 

Figure 20-17 Static mixer used in pulp suspension mixing applications. Shown is the Komax steam mixer used in medium consistency applications.

Two-part mixed-type acrylic adhesives are applied like two-part mixed epoxy adhesives with meter or meter-and-mix equipment. The two parts may be metered into a container for immediate mixing and application, or metered into a static mixer and inunediately dispensed to the adherends to be joined. A simple illustration of meter-and-mix equipment is the double-barrel syringe, which delivers the two parts of the adhesive to a nozzle containing static mixing elements. These elements are alternating right and left hand helices connected off center to each other. At the other end of the complexity spectrum is the equipment for automated assembly lines. 

The cleats are bonded with an array of tools for ensuring a stress-free assembly after the surface preparation (sanding/ethanol wiping), the adhesive being applied in situ with a tube mixing device, with the dedicated static pressure application during hardening. 

To minimize possible sources of error and improve the application procedure that directly enhances the bond properties, several tools can be used to stabilize the joining process. The utilization of static mixing tubes, which are available for almost every two-part adhesive system... 

Conveyor-Belt Devices The metal-belt type (Fig. 11. 55) is the only device in this classification of material-haudhug equipment that has had serious effort expended on it to adapt it to indirecl heat-transfer seiwice with divided solids. It features a lightweight construction of a large area with a thin metal wall. ludirect-coohiig applications have been made with poor thermal performance, as could be expected with a static layer. Auxihaiy plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this seiwice, restrict applications. 

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