英文原文New energy-saving mechanical mixer and Overview of adaptable die design for extrusionAbstractIn the work there are described the results from the laboratory researches of the basic characteristics (performance) of one new type of energy-saving mechanical mixer, conditionally named Eleron. These characteristics (performance) are compared with respective results of the other known in the literature and successfully used in practice mixers. The mixer is designed for mixing and aerating liquid systems and it will be effective for mixing in the ferment reactors for biochemical industries, where the processes are energy absorbing. Keywords: Mixer; Air-saturation; Power-number; Heat and mass-transfer during mixing; Aeration-number1. Introduction In implementing a long-term, energy-saving program for industry 1, the department of Heat and Mass-Transfer Technics in TU-Sofia, under the guidance of the author, has conditionally created for patent an original construction of energy-saving mixer. It has a universal function for mixing liquid systems in chemical, food, wine, tobacco, and biochemical industries. We expect our mixer to take its place with dignity in fermentation technics, because of its easy manufacture, good results in air-saturation and low energy consumption. Till now it was the investigated laboratory version of Eleron-1 mixer, which is a small type, with D=(0.25/0.35)T. Universal appearance of mixer is shown in Fig. 1. It consists of a central round disk (1), which is carrying pap (2) and four wings (3). The wings are cut through in the middle (aa) and in the beginning, near the round disk (cc), and the receiving pieces are bend arch-shaped up and downward, making four blades with radius R=(0.05/0.07)D. Their length is L=0.8pR, as (considered) from line of bend. The blades on each following wing are in different order in bend direction, and because of this in working conditions there are circumstances for vortexes. This is very important when there is more than one mixer on a shaft (Figs. 1 and 2). When mounting, we observe the axial flows, created by curved blades, to meet each other (if we aim air saturation) or to pass each other, when we aim mixing without aeration. In this way we create multitude of symmetrical current lines (vortexes), which spread symmetrically vessel.2. ExperimentalFor researching characteristics (performances) of mixer Eleron-1 there are used two identical laboratory reactors with plane bottom and releasers, respectively with volumes 6.5 and 24 dm3. Reactors diameters are, respectively 190 and 300 mm, and mixers are make up with D_0.35T. As pattern substances there are used water and die thylene glycol, which under 20C have dynamical viscosity and Pa s. Reactors configuration is on Fig. 2 and the experiment tal installation, which is used, is on Fig. 3. With this installations configuration we are researching the power consumption, working with and without aeration , heat-transfer during mixing with Eleron-1, that is why reactors have heat-transfer bogies-worm-pipes (serpentines) with respective tube diameter d1 and wind up diameter dS, which are on Fig. 2. For measuring DO2 (dissolved oxygen) in liquid phase during aeration, installation also has a bottle with nitrogen, air-compressor, sensor for DO2and a writing instrument, which register on the tape the oxygen absorption (Fig. 3).Fig. 1. Scheme of mechanical mixer Eleron-1 in appearance from above.2.1. Power coefficient determination For this mixers characteristic are usedtwo reactors and two pattern substances, and the rotation frequency of mixers shaft is changing from 100 to 1200 min_1. Rotation frequency is chosen and fixed and after that is controlled with electronic cyclometer. Eu-number is determined under equation and it is read net power consumption P, for respective rotation frequency . The dependency is in Fig. 4 and is compared with the dependency of Rush ton-turbine.2.2. Aeration-number determination This exponent is defined under known methods, which is adopted for mixing technics. In our reactor with volume 6.5 dm3, with the help of air-distributed mechanism, the air is entranced with flow of qG_0.1 to1.5 V . The researching results are on Fig. 5 and are compared and heat-transfer surface (serpentine). Fig. 2. Configuration of laboratory reactors with mechanical mixerFig. 3. Scheme of experimental installations: 1, thermostat; 2, reactor; 3, pressure vessel; 4, heat-transfer surface (serpentine)2.3. Mass-transfer coefficient determination during mixing with Eleron-1 There are used two reactors with different volumes, which have air-distributed mechanisms and sensor form easuring and registering of CO2 in water. We work under 20C, and the liquid phase, before each attempt, is scavenged with nitrogen until initial oxygen concentrationC0, which is changing progressively and is wri