LITRE METER
Expert Flow Measurement Engineering
HIGH PRESSURE: Flow Meters for 20,000 PSI and Above
Litre Meter has always focused particularly on extreme measurement conditions involving low flow and/or high pressure. The VFF series is used in many applications within the oil and gas industry and meets the required high specifications. Beyond the oil and gas sector, it also serves applications up to 2,500 bar. A few years ago, the growing demand for 20,000 psi applications in the Gulf of Mexico led to the installation of our flow meters in projects across the region.
Since 1997, numerous VFF meters have been manufactured for oil and gas applications at pressures of 1,380 bar. With minor modifications, the same design can be used at 22.5 psi (1,550 bar).
A major development in our design approach occurred when we separated the liquid measurement section from the pressure enclosure. We designed a measuring chamber that floats within the pressure vessel. This configuration provides accurate, pressure-independent flow measurement from 10 psi to 20,000 psi. Further information about the Pressure Balanced Chamber is provided below.
What Is a Pressure Balanced Chamber?
Comprehensive testing carried out by Litre Meter in 2005 showed that leakage occurred at the top of the rotor at higher pressures and that this was caused by minor deformation of the cover. For example, at 700 bar, the center of the cover moves by only 0.02 mm. Increasing the mass of the cover still causes this movement to continue. The effect on flow meter performance was the formation of a liquid leakage path that interfered with the rotor’s positive displacement.
At 700 bar, this effect was equivalent to an approximately 3% measurement error. As a result, Litre Meter designed a Pressure Balanced Chamber to enable VFF flow meters to operate at high pressures and low flow rates.
The Pressure Balanced Chamber acts as a barrier that protects the internal measuring components of the device from high-pressure conditions, preventing expansion and contraction under extremely high pressure. Preventing deformation enables accurate measurement under varying pressure conditions. All VFF units are equipped with this technology, identified by the abbreviation PBC on the calibration certificate.
Fluids and Ranges
For approximately 40 years, VFF has successfully measured a wide variety of fluids and chemicals, including oils, hydraulic fluids, corrosion inhibitors, 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. In the offshore oil industry, flow rates as low as 0.00013 liters/min (0.19 liters/day) have been measured. Depending on operating viscosity, the VFF flow meter provides a turndown ratio of up to 3000:1.
Meter sizes range from the smallest standard stock size, LF03 – 18 L/h, up to a maximum HF40 – 40 L/min. Custom flow meters are available for higher flow rates. A wide variety of flow meter designs and materials provide pressure capability up to 20,000 psi (1,380 bar). Designs with higher pressure ratings, up to 2,500 bar (36,000 psi), are also available. Standard designs suitable for pressures of 20,000 psi are available for flow rates up to 40 L/min, while custom designs can measure higher flow rates.
All VFF flow meters are individually calibrated according to the minimum and maximum flow conditions specified by the customer and the operating viscosity. The minimum achievable flow rate depends on the viscosity of the liquid. We can provide meters suitable for applications at 20 ksi, covering flow rates from 0.005 L/h to 3,600 L/h and offering exceptional turndown ratios.
