Understanding Pressure Control in Hydraulic Systems: A Guide

Pressure control in hydraulic systems is a critical aspect of operational safety within process and manufacturing plants. One of the common issues faced is the rapid cycling of pressure valves, which can lead to hydraulic hammer—a phenomenon that generates shock waves in the system and potentially causes pipeline ruptures or system overpressure. While piping is designed to handle worst-case scenarios, strict adherence to established operational procedures is essential to mitigate risks.

Another significant risk stems from operator inattention, particularly during the filling of storage tanks. Overfilling can result in system overpressurization, prompting the need for effective safety mechanisms like liquid-level indicators that sound alarms when levels reach a critical threshold. Installing excess-flow valves at tank entrances and configuring pumps to shut off when nearing maximum capacity are proactive measures that can help avoid hazardous situations.

Temperature fluctuations can also impact pressure systems, especially under solar effects. However, in most cases, the thermal expansion is insufficient to cause significant issues. It's important to note that while some conditions—such as low liquid levels in systems—can lead to operational inefficiencies, they are often manageable through procedural controls. For instance, the use of nitrogen purges during processes helps to maintain efficient flow and prevent cavitation in pumps.

Operator errors such as forgetting to close the scrubber line while filling tanks can have dire consequences. Such mistakes can introduce contaminants into the system, causing ice formation in ammonia lines and leading to dangerous pressure buildups. To prevent such occurrences, it's advisable to install filters at pump inlets and ensure that all fittings are compatible with ammonia to avoid chemical reactions that could compromise system integrity.

It is crucial to recognize that while hazard analysis and operational procedures aim to identify risks, they are only as effective as the diligence of the team involved. Maintaining awareness of potential hazards and reinforcing training in best practices can significantly reduce the likelihood of errors and enhance the overall safety of hydraulic systems in industrial settings.