Specialist Flow Measurement Engineering
HIGH PRESSURE: Flow Meters for 20,000 PSI and Beyond
Litre Meter has always focused on the extremes of measurement, typically at low flow rates and/or high pressures. The VFF series has numerous applications in the Oil and Gas industry and meets the demanding specifications required. Beyond the oil and gas sector, we also serve applications up to 2,500 bar. Several years ago, the trend toward 20,000 psi applications in the Gulf of Mexico resulted in our flow meters being installed in projects throughout the region.
Since 1997, numerous VFF meters have been manufactured for oil and gas applications operating at 1,380 bar. With minor modifications, the same design can also be used at 22.5 ksi (1,550 bar).
The breakthrough in our design philosophy came when we separated the fluid measurement system from the pressure containment. We designed a measuring chamber that floats within the pressure vessel. This enables accurate, pressure-independent flow measurement from 10 psi to 20,000 psi. An explanation of the Pressure Balance Chamber is provided below.
What Is a Pressure Balance Chamber?
Extensive testing conducted by Litre Meter in 2005 demonstrated that leakage occurred over the top of the rotor at higher pressures. This was caused by slight deformation of the cover. For example, at 700 bar, the cover deflects by only 0.02 mm at its center. Increasing the mass of the cover still resulted in this movement. The effect on flow meter performance was the creation of a leakage path for the fluid, preventing the rotor from maintaining positive displacement.
The result was an inaccuracy of approximately 3% at 700 bar. Consequently, Litre Meter developed a Pressure Balance Chamber for VFF flow meters, enabling operation at extremely high pressures and low flow rates.
The Pressure Balance Chamber acts as a barrier that protects the internal measuring components of the instrument from high-pressure conditions, preventing expansion and contraction under extreme pressure. The absence of deformation ensures accurate measurement at any pressure. All VFF flow meters are equipped with this technology, identified by the letters PBC on the calibration certificate.
Fluids and Ranges
For approximately 40 years, the VFF has successfully measured fluids including oils, hydraulic fluids, corrosive chemicals, waxes, emulsifiers, pour point depressants, scale inhibitors, hydrate inhibitors, biocides, and oxygen scavengers. Flow meter bodies are manufactured from a range of high-quality materials offering excellent chemical and environmental resistance. Applications in the offshore oil industry have measured flow rates as low as 0.00013 L/min (0.19 L/day). Depending on the operating viscosity, the VFF flow meter provides an exceptional turndown ratio of up to 3000:1.
Meter sizes range from the smallest standard stock model, LF03 – 18 L/hr, to the maximum standard model, HF40 – 40 L/min. Higher flow rate meters are available on special order. A wide variety of flow meter designs and materials provide pressure ratings up to 20,000 psi (1,380 bar). Higher-pressure designs rated up to 2,500 bar (36,000 psi) are also available. Standard designs are available up to 40 L/min at 20,000 psi, while custom designs can accommodate higher flow rates.
All VFF flow meters are individually calibrated according to the customer’s specified minimum and maximum flow conditions and operating viscosity. The minimum achievable flow rates depend on the viscosity of the fluid. We can provide meters covering flow rates from 0.005 L/hr to 3,600 L/hr, optimized to suit your applications at 20 ksi pressure while delivering exceptional turndown capability.
