In a fluid distribution center (any fluid) the resistance created by the pipes, distribution checkpoints, flow meters, and traveled distance is measured against the viscosity of the fluid. Pump pressures must be set to a value that causes the fluid to flow at a rate that overcomes the backpressure resistance.
In other words… How much pressure is required to get the fluid to travel through all the pipes and valves so it can be dispensed?
Resistance in pipelines is friction based. Backpressure is required to get fuel from the tank to the fill nozzle.
- Friction between the fluid and the wall of the pipe as the fluid travels through the network.
- Resistance or friction between parallel layers of the fluid itself – the fluid can create its own friction as it sloshes.
- Friction loss occurs as the fluid travels through any pipe. The fittings, bends, valves, or components or other disruptors slow the flow.
- Pressure loss due to a change in elevation of the fluid (if the pipe is not horizontal) Moving uphill creates a resistance.
- Pressure gains due to any fluid that is helped by a pump.
Engineers take all of these factors into consideration as they calculate the pressure inside a tank. They will take advantage of gravity and the weight of the fluid itself as a valve opens. The distance between the tank and nozzle, the declivity of the pipe system and the resistance of all the hardware put in place to direct or increase the flow will determine the amount of pressure that will be applied inside the tank.
Increasing the backpressure speeds the flow of any liquid in a pipeline to its endpoint. The applied pressure is what pushes the fuel through the system. A decrease will slow or even halt the flow of product.