MECHANICAL SEAL MONITORING AND CONTROL SYSTEM FOR CENTRIFUGAL PUMPS

Abstract

Centrifugal and rotary positive displacements pumps require controlling of the pumped fluids tend to exit through the stuffing box. A mechanical seal is a sealing device which forms a running seal between rotating and stationary parts, uses to prevent proCentrifugal and rotary positive displacements pumps require controlling of the pumped fluids tend to exit through the stuffing box. A mechanical seal is a sealing device which forms a running seal between rotating and stationary parts, uses to prevent product leakage, reduced friction and power loss and Elimination of shaft or sleeve wear. A basic mechanical seal is not a complex device. It consists primarily of a rotary seal face with a driving mechanism which rotates at the same speed as the pump shaft. The primary seal is achieved by two very flat faces, which make it extremely difficult for the fluid to escape between them. The barrier fluids form a thin layer or oil film between the faces which is used to cool and lubricate the seal faces. Mechanical seal components and functions are so difficult to be monitored directly, accordingly it is not easy to prevent failures, beside when the device failes there is no way to analyze it and find the root cause. The best way to monitor and control the mechanical seal is to use the parameter of the barrier fluid as indication for the seal condition such as the pressure and temperature. With the fact that many seal failures are related to the pumped fluid pressure and temperature, the addition of these parameters to the seal monitor system, will help in better understanding of the seal behavior. In this research a statistical study for the BURGMAN Mechanical seal failures is used as a guide to design a monitoring system. The research is intended to help in the failure analyses by monitoring of the temperature and pressure. On the other hand it will provide simple methods to control the seal pressure. The design utilizes the existing control system with addition to some measuring points and few control outputs. duct leakage, reduced friction and power loss and Elimination of shaft or sleeve wear. A basic mechanical seal is not a complex device. It consists primarily of a rotary seal face with a driving mechanism which rotates at the same speed as the pump shaft. The primary seal is achieved by two very flat faces, which make it extremely difficult for the fluid to escape between them. The barrier fluids form a thin layer or oil film between the faces which is used to cool and lubricate the seal faces. Mechanical seal components and functions are so difficult to be monitored directly, accordingly it is not easy to prevent failures, beside when the device failes there is no way to analyze it and find the root cause. The best way to monitor and control the mechanical seal is to use the parameter of the barrier fluid as indication for the seal condition such as the pressure and temperature. With the fact that many seal failures are related to the pumped fluid pressure and temperature, the addition of these parameters to the seal monitor system, will help in better understanding of the seal behavior. In this research a statistical study for the BURGMAN Mechanical seal failures is used as a guide to design a monitoring system. The research is intended to help in the failure analyses by monitoring of the temperature and pressure. On the other hand it will provide simple methods to control the seal pressure. The design utilizes the existing control system with addition to some measuring points and few control outputs.