Improvement of the Process of Mechanical Dehydration of Five-Layer Semi-finished Wet Leather Products

To improve the process of mechanical dehydration of semi-finished wet leather products, a multilayer dehydration using felt materials – monshons was experimentally investigated. The process is conducted by vertical feed of semi-finished wet leather products on a base plate between rotating squeezing rollers. The D-optimal method of mathematical planning of the experiment and the Kano design matrix were used for conducting experiments. The multi-layer package consists of five layers of semi-finished wet leather products and two layers of moistureremoving materials between each layer, folded over the base plate. The studies were carried out in laboratory conditions on an experimental bench, taking into account the production parameters of processing. As a result of the study, mathematical dependences of the amount of removed moisture for each of five layers of semifinished wet leather product on the feed speed and the pressure of the squeezing rollers were derived. The analysis of the results showed that, with the existing parameters of mechanical dehydration, it was possible to simultaneously squeeze out moisture from five layers of the semi-finished leather product with a minimum pressure of the squeezing rollers and an average feed speed. The productivity of the technological process was more than five times higher in comparison with the productivity of similar roller machines. In the near future, this research methodology will be used to determine the technological factors affecting the extraction of excess moisture from a package consisting of ten semi-finished wet leather products and moisture-removing materials

Improvement of the Process of Mechanical Dehydration of Five-Layer Semi-finished Wet Leather Products

To improve the process of mechanical dehydration of semi-finished wet leather products, a multilayer dehydration using felt materials – monshons was experimentally investigated. The process is conducted by vertical feed of semi-finished wet leather products on a base plate between rotating squeezing rollers. The D-optimal method of mathematical planning of the experiment and the Kano design matrix were used for conducting experiments. The multi-layer package consists of five layers of semi-finished wet leather products and two layers of moistureremoving materials between each layer, folded over the base plate. The studies were carried out in laboratory conditions on an experimental bench, taking into account the production parameters of processing. As a result of the study, mathematical dependences of the amount of removed moisture for each of five layers of semifinished wet leather product on the feed speed and the pressure of the squeezing rollers were derived. The analysis of the results showed that, with the existing parameters of mechanical dehydration, it was possible to simultaneously squeeze out moisture from five layers of the semi-finished leather product with a minimum pressure of the squeezing rollers and an average feed speed. The productivity of the technological process was more than five times higher in comparison with the productivity of similar roller machines. In the near future, this research methodology will be used to determine the technological factors affecting the extraction of excess moisture from a package consisting of ten semi-finished wet leather products and moisture-removing materials

A Study on the Pressure Mechanism Improvement of a Roller-Type Machine Working Bodies

The parameters of the improved design of the pressure mechanism of a roller technological machine for squeezing wet materials are investigated in this article. The factors influencing the parameters of the pressure mechanism, which provide the required force between the working rolls of a technological machine during the processing of moisture-saturated fibrous materials, such as wet leather, were studied. The processed material is drawn in the vertical direction between the working rolls under their pressure. This study aimed to determine the parameters that make it possible to create the required pressure of the working rolls depending on the change in the thickness of the material being processed. A pressure mechanism of working rolls mounted on levers is proposed. In the design of the proposed device, the length of the levers does not change due to the movement of the sliders when turning the levers; this provides a horizontal direction of the sliders. The change in the pressure force of the working rolls is determined depending on the variation in the nip angle, the coefficient of friction, and other factors. Based on theoretical studies concerning the feed of the semi-finished leather product between the squeezing rolls, graphs were plotted, and conclusions were drawn. An experimental roller stand designated for pressing multi-layer leather semi-finished products has been developed and manufactured. An experiment was carried out to determine the factors affecting the technological process of squeezing excess moisture from wet semi-finished leather products with their multilayer package together with moisture-removing materials by means of their vertical supply on a base plate between rotating squeezing shafts also covered with moisture-removing materials. According to the results of the experiment, the optimal process parameters were selected. It is recommended to carry out the process of squeezing the moisture from two wet semi-finished leather products at a pass rate more than twice as high and with a pressing force of the working shafts two times lower compared to the analog. According to the results of the study, the optimal parameters for the process of squeezing the moisture from two layers of wet leather semi-finished products were chosen, namely the feed rate of 0.34 m/s and a pressing force of the squeezing rollers of 32 kN/m. The use of the proposed roller device allowed an increase of two times or more in the productivity of the process of processing wet leather semi-finished products on the basis of the proposed technique compared to known roller wringers

The Improvement of the Rheological Model of Leather

Fibrous capillary-porous materials, such as woven materials and leather, used in the light industry for clothing and footwear, differ sharply from metallic materials. These differences manifest themselves in a complex relationship between stress and strain, which depends on the strain rate and loading time. A method for determining the identified new rheological parameter of the inert resistance of a capillary-porous material (for example, leather) of accelerated deformation is presented in the article; it consists in determining the indentation force of a conical indenter at a constant speed and the coefficient that considers shear zones, and the angle formed by the boundaries of the material deformation zone and application of force value. An equation for an improved rheological model of leather is derived; it consists of the Kelvin model, the Bingham-Shvedov model, and the Khusanov model, expressed in terms of the rheological parameter in the form of a deformation inertness coefficient. The inclusion of the model of deformation inertness in the form of a coefficient into the rheological model of leather will allow the mathematical description of the rheological parameters of leather and the development of engineering methods for their calculation. The implementation of the developed method will allow obtaining numerical values of the rheological parameter of the inert resistance of the capillary-porous material under its accelerated deformation, namely, a new property of the capillary-porous material, which must be taken into account in various technological processing operations, for example, when treating moisture-saturated leather