bakströmning

Bakströmning, or backflow, is the movement of a fluid in the opposite direction to the intended or normal flow within a system. The term is used in hydraulics, water engineering, and process industries to describe situations where reverse flow can occur, potentially leading to contamination, inefficiency, or safety risks.

Backströmning can arise from pressure fluctuations, pump failures, valve closures, blockages, siphoning effects, or design flaws in piping and drainage networks. It may occur in municipal water supplies, industrial process lines, heat exchangers, and sewer systems. The phenomenon is of particular concern when contaminated or incompatible fluids can enter clean or critical flows.

Prevention and control focus on maintaining unidirectional flow and isolating vulnerable sections. Common measures include backflow prevention devices such as check valves and air gaps, reduced pressure zones, proper venting, and careful system layout to avoid backpressure and siphonage. Compliance with local codes and standards for backflow prevention is typical in both drinking water and industrial contexts.

Measurement and monitoring of bakströmning involve detecting reverse flow and alerting operators. Techniques include flow meters with directional capability, differential pressure sensors, and dedicated backflow alarms. Regular testing and maintenance of backflow prevention devices are essential to ensure continued effectiveness.

See also: backflow, siphon, check valve, backpressure, backflow prevention.