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Diesel Fuel Flow Meters & Diesel Flow Sensors: Custody Transfer Trackers for Refinery Fleets

Quick Answer: For refinery fleet diesel custody transfer, choose an oval gear flow meter for value or a Coriolis mass flow meter for 0.1 percent accuracy. Silver Automation Instruments supplies diesel flow meters from DN15 to DN100 with pulse, 4-20 mA HART, or Modbus RTU output, plus ATEX Zone 1 and Zone 2 options. Send pipe size, flow range, pressure, temperature, and diesel viscosity for a quote.

Why Refinery Fleets Need Diesel Custody Transfer Meters

Refinery fleets fuel loading arms, diesel bowsers, generator sets, and site trucks. Each transfer needs a recorded volume or mass. A pulse output with a totalizer is the standard way to track diesel volume. For custody transfer inside a refinery or to a third party, temperature compensation matters. Diesel density changes about 0.5 percent for every 10 °C shift. At 40 °C, diesel viscosity usually sits between 2.0 and 4.5 cP.

We have seen terminals in the Middle East print delivery tickets from oval gear meters with temperature compensation. The engineer checks the batch controller, not the truck dipstick. That is the practical standard. If the meter drifts or the air eliminator fails, disputes start within days. For legal custody transfer, accuracy should be 0.1 percent or 0.15 percent. Coriolis mass flow meters meet this. For internal fleet tracking, 0.5 percent is usually enough. Do not use a turbine meter on dirty diesel without a 60 mesh strainer.

Meter Types That Work for Diesel

Oval gear flow meter. An oval gear diesel flow meter is the most common choice for fleet custody transfer. It measures volume directly. Two oval gears rotate with each diesel volume segment. Output is pulse or 4-20 mA. For diesel, we recommend aluminum or 316L body, PPS gears, and FKM seals. Flow ranges from 20 L/h to 60 m3/h cover small bowser pumps and medium loading arms. Accuracy is 0.5 percent standard, 0.2 percent optional. Battery powered totalizers work well on mobile bowsers.

Coriolis mass flow meter. A Coriolis meter measures mass flow, volume flow, density, and temperature. No rotating parts sit in the diesel stream. Accuracy is 0.1 to 0.15 percent for mass. For a refinery loading rack with a terminal automation system, Coriolis sends Modbus RTU or HART data. Use DN15 to DN50 for truck loading arms. The main limit is cost.

Ultrasonic and turbine flow meters. Clamp-on ultrasonic meters can check existing diesel lines but are not a first choice for custody transfer. Accuracy shifts with pipe scale, couplant aging, and flow profile. Turbine meters work on clean, filtered diesel. They need straight run and a strainer. In refinery fleets, diesel can carry wax or rust particles. Bearing wear changes the K-factor slowly. That is why we prefer oval gear or Coriolis for diesel.

Key Specifications for Refinery Diesel Flow Measurement

Line size matters. Most diesel bowsers and fuel skids use DN15 to DN80. Some depots use DN100 for high flow loading arms. Pressure rating is usually PN16 for storage loops, PN40 for pump discharge lines, and ANSI 150 for export terminals. Temperature range from -10 to 80 °C covers most diesel metering. Wetted parts for non corrosive diesel are aluminum body with FKM or PTFE seals. Coastal or high humidity sites should use 316L stainless steel.

Output choices depend on the control system. Pulse suits local totalizers. 4-20 mA suits PLC analog input. RS485 Modbus RTU suits terminal automation. HART is useful for smart commissioning. Refinery loading racks often need ATEX Zone 1 or Zone 2. We supply Ex d and Ex ia versions. Power is usually 24 VDC. Some oval gear meters work with battery powered totalizers for mobile bowsers.

Installation Advice from Field Jobs

A diesel meter should never run dry. Air slugs cause oval gear