Machinery & Energetics (Feb 2023)
Improvement of motorized design filtering respirator
Abstract
Working conditions, in terms of hygiene, harmful impurities in the air of the working area, often do not meet regulatory requirements. In such cases, motorized filter respirators are used to protect respiratory organs, which require the development of an appropriate system for managing operational indicators for effective operation. The purpose of the article was to improve the control system of a motorized filter respirator to increase protective efficiency, due to the development of a new parametric scheme of the control object, taking into account the functional relationships between the operating mode, air flow, filter resistance and the term of protective action. To create an appropriate control system, a structural-parametric synthesis of operational indicators management was applied, based on the relationships between the main variables (outgoing regulated variables, controlling influences and disturbances). A new working diagram of the control object with selected design elements of the blower has been developed, the main difference of which is the use of the “Arduino Uno R3” board, the “LCD Keypad Shield” module with a two-line display for controlling the air flow modes, in accordance with the change of the filter resistance taking into account the accumulation dust deposit based on the assumption that the transfer function can be represented by an aperiodic link of the 1st order with sufficient accuracy for practice. To work out the operating modes and determine the duration of the protective effect, a software model of the operation of the motorized filter respirator was created, which made it possible to evaluate the influence of the dust concentration on the change in air flow through the filter elements, taking into account the accumulation of dust sediment on the protective effectiveness. Recommendations have been developed to ensure the effective functioning of the protective device in accordance with the requirements under the most unfavorable conditions. The practical value of the work lies in the fact that the modes of movement of the air flow are determined, in accordance with the speed of rotation of the fan blade from the width of the PWM pulses, which depend on the resistance of the filter, the accumulation of dust deposits based on the transfer function
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