tilbakestrømming

Tilbakestrømming is a term used in Norwegian to describe the reverse movement of liquids or gases in a system, i.e., when flow reverses direction against the intended path. It occurs whenever there is a pressure difference that causes the medium to move backward. The phenomenon is relevant in plumbing, water-treatment, pool maintenance, and industrial processes, as well as in environmental hydrology where it can influence groundwater and surface-water interactions.

There are two common mechanisms: backpressure, where upstream pressure exceeds downstream pressure and pushes the fluid backward; and backsiphonage, where a drop in supply pressure draws fluid backward through a connection. Backflow can lead to contamination of potable water, cross-contamination in process lines, or damage to equipment.

Prevention and control rely on backflow prevention devices and proper system design. Check valves (non-return valves), air gaps, and backwater valves are commonly used to block reverse flow. System layouts, isolation valves, and pressure management also reduce risk. Standards and regulations in many countries require backflow protection for critical connections between potable water and potentially contaminated sources.

In pool maintenance, backwashing uses controlled reverse flow to clean filter media. In engineering and environmental contexts, understanding backflow helps manage flood risks, groundwater-surface water exchange, and the integrity of water-supply networks.