A Guide to Bitumen & Pump Selection
What is Bitumen & Where is it Used?
Bitumen or asphalt has a wide range of uses both in refining, and within the pavement, road and roof construction. Bitumen acts as a glue, binding aggregate particles together and has excellent sealing properties resisting water ingress and is insoluble in water. Its durability, abundance and cost of manufacture make it an economical solution for covering large areas.
Depending on the grade of Bitumen it will be heated to between 140°C-170°C before being mixed with aggregate and applied. Due to asphalts viscous nature, a typical bitumen pump specification will be cast iron gear pumps which are running slowly to minimize wear with hardened teeth.
Pumping Difficulty
Due to its potential to solidify within the equipment, it is important heating jackets are installed on any pumps to prevent it from cooling, keeping it in liquid form and at a low viscosity. Seal options include packed gland which provides seal longevity as it is less susceptible to damage than a mechanical seal upon startup if the asphalt has solidified within the pump. Magnetic couplings can be used to make pumps entirely seal free. Bitumen emulsion pumps are typically constructed without a relief valve as external relief valves are used which are not susceptible to clogging.
Typical applications include spraying, transfer, unloading and filling.
Typical SG: 0.97 - 1.02
Typical viscosity: 400cst - 3200cst
