The materials used to construct an oil flowmeter must be compatible with the specific petroleum product being measured and capable of withstanding the expected operating pressure, temperature, and chemical environment. The wrong material selection can lead to corrosion, swelling of seals, contamination of the fluid, or premature failure of measuring elements. Most flowmeter manufacturers offer several material configurations to accommodate the broad range of fluids and conditions encountered in oil measurement applications.
The meter body (housing) is typically made from cast iron, ductile iron, stainless steel (304 or 316L), aluminum, or bronze, depending on the pressure rating and corrosion resistance required. For crude oil and fuel oil applications, cast iron or ductile iron is commonly used for cost-effective, moderate-pressure service. Stainless steel bodies are preferred for corrosive petroleum products, high-purity applications, or high-pressure service. Aluminum is used in lower-pressure applications where weight is a concern, such as portable fuel transfer meters. The internal measuring elements—gears, rotors, bearings—are made from materials that combine wear resistance with compatibility, including hardened stainless steel, carbon-filled PTFE, and ceramic.
Seals and gaskets are critical for containing the oil and preventing external leaks. Common seal materials include Viton (FKM), Buna-N (NBR), EPDM, and PTFE, each with different chemical compatibility profiles. Viton is generally the most chemical-resistant and is suitable for a wide range of hydrocarbons, fuels, and aromatic compounds. Buna-N is suitable for mineral oils, fuels, and hydraulic fluids but not for aromatic or halogenated solvents. PTFE is the most chemically inert material and is used for the most aggressive fluids. Selecting the correct seal material for the specific oil being measured is critical for leak prevention and long-term meter reliability.