Optimized sulfur curing of pulse-damping rubber tubes

Abstract

In pumping systems present in the industrial field, positive displacement pumps are used due to the high manometric loads and the characteristics of the extracted fluid. However, this type of pump provides a pulsating flow in the system that causes large pressure fluctuations, reducing the useful life of the installations. Because of this problem, pulsation dampers (attenuators) are used in the system in order to promote a more continuous flow and the good functioning of the process. In-line type attenuators feature a flexible tube composed of elastomer, whose viscoelastic behavior causes flow attenuation. The objective of this work is to evaluate whether there is a relationship between the sulfur content present in blends of natural rubber (NR) and synthetic rubber of the Butadiene Styrene (SBR) and the performance of tubular attenuators in a pumping system with pulsating flow. Four NR/SBR rubber blends with different sulfur concentrations in the formulation (0.5; 1.5, 3.0 and 4.5 phr) were tested. The rubbers were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and their mechanical properties were analyzed using mechanical tensile tests. The efficiency of the attenuators was evaluated through bench tests that simulate pumping systems in the field. The results of the mechanical tests showed significant relationships with the performance of the attenuators in experimental tests. In attenuation tests, blends with 1.5; 3.0 and 4.5 phr sulfur had attenuation results of 27.06 %, 9.70 % and 1.61 %, respectively. The 0.5 phr attenuator could not withstand the applied loads due to lack of elastic properties. Thus, it was found that materials with a lower modulus of elasticity had greater efficiency in attenuating the pulsating flow and greater compliance, in which the attenuator that was formulated with 1.5 phr of sulfur showed 25.45 % greater pulsation damping than the stiffer material.