ABSTRAC The aim of this work was to innovate the design of an axial thrust Kingsbury bearing for submersible vertical centrifugal pumps, using glass as a friction resistant material between the rotating disc and the skids, in order to increase its useful life and save energy intensity current. The exploitation parameters were determined as volumetric flow entering the skid, maximum thrust pressure and maximum load coefficient, among others. For the 124 submersible pumps tested, the results showed an average increase of 3.11 years in their useful life and an average saving of 2.5 ampere for each pump when they operated with glass bearings with respect to the conventional bearings of fabric.

RESUMEN El objetivo de este trabajo fue innovar el diseño de un cojinete Kingsbury de empuje axial para bombas centrífugas verticales sumergibles, utilizando vidrio como material resistente a la fricción entre el disco giratorio y los patines, con la finalidad de aumentar su vida útil y ahorrar intensidad de corriente. Se determinaron los parámetros de explotación como flujo volumétrico que entra en el patín, presión máxima de empuje y coeficiente de carga máxima, entre otros. Para las 124 bombas sumergibles ensayadas, los resultados presentaron un incremento promedio de 3,11 años en su vida útil y un ahorro promedio de 2,5 ampere por bomba cuando operaron con cojinetes de vidrio respecto de los cojinetes convencionales de fábrica.

Abstract This study presents the environmental evaluation of an abandoned and potentially contaminated landfill using analyses for the presence of heavy metals and for methane generation potential. The site is located in the city of Santiago, Chile, and was used as a rural landfill for domestic, industrial and construction waste until 1978, but is now in a heavily urbanized area and surrounded by houses. Analyses performed on 24 samples taken in and around the site show Potential Methane Generation (PMG) values between 1.6% and 11.3% of maximum projected levels. These low values, compared to those of an active landfill, indicate that waste material stored in the site has a low capacity to generate methane. Concentrations of heavy metals in the surface and deep soil are similar to typical levels for these metals in normal soil, according to international USEPA standards, and do not present imminent risk to human health. The use of the PMG test technique for the study of the health risk of an abandoned landfill is a new contribution to the Chilean evaluation methodology and management program for Abandoned Sites with Potential Presence of Contaminants (SAPPC). As part of the environmental management strategy for the site, two of the five operable units studied were transformed into a park after this study.

This work is developed in order to determine the rheological properties of the paste for the production of Portland cement factory " 26 de Julio" of Nuevitas, Cuba, depending on the moisture content. Samples were prepared at 38, 40, 42, 45 and 47% humidity, and the viscosity was measured with a rotational viscometer. It was observed that the pulp has a pseudo plastic behavior that fits models Ostwald de Waele and Metzner-Reed. The relationship between the index flow coefficients "n" and consistency index "k" in the model Metzner-Reed was obtained, resulting in "n" increased with increasing moisture while "k" decreased. The characteristic curves of the water pumps and paste for the production of cement was obtained. When paste is used, the pump efficiency decrease and power increased in comparison with water used. A brief economic analysis shows that for the design capacity of the factory, a decrease in moisture content of the dough into two percentage units, representing a considerable saving of fuel.

Este trabajo se desarrolla con el objetivo de determinar las características reológicas de la pasta para la producción de cemento Portland en la fábrica “26 de julio” de Nuevitas, Cuba, en función del contenido de humedad. Se prepararon muestras a 38, 40, 42, 45 y 47% de humedad y se midió la viscosidad con un viscosímetro rotacional. Se observó que la pasta tiene un comportamiento pseudoplástico que se ajusta a los Modelos de Ostwald-de Waele y de Metzner-Reed. Se obtuvo la dependencia del índice de flujo “n” y del índice de consistencia “k”, en el modelo de Metzner-Reed, resultando que “n” aumentó con el incremento de la humedad mientras que “k” disminuyó. Se obtuvieron las curvas características de las bombas para agua y pasta para la producción de cemento, donde se aprecia un decrecimiento de la eficiencia de la bomba y un aumento de la potencia, cuando se utiliza pasta en comparación con el uso de agua como fluido. Un breve análisis económico muestra que para la capacidad de diseño de la fábrica, una disminución del contenido de humedad de la pasta en dos unidades porcentuales, representa un considerable ahorro de combustible.