Flow meters for 20,000 PSI and beyond
Litre Meter has always concentrated on the extremes of metering, typically at low flows and/or at high pressure. The VFF range has many uses in the oil and gas industry and meets the high specifications required. Outside of oil and gas, 2,500 bar meters are in service. A few years ago, the trend towards 20,000 psi ratings in the Gulf of Mexico saw our flow meters installed in projects in the region.
Since 1997 numerous VFF meters for 1,380 bar in oil and gas applications have been made. The same design can be used on 22.5 psi (1,550 bar) with minor modification.
The breakthrough in the design philosophy came when we separated the fluid measurement from the pressure containment. We designed a measurement chamber that floats in the pressure vessel. This ensures accurate, pressure-independent flow metering from 10 psi to 20,000 psi. An explanation of the Pressure Balance Chamber can be found below.
What is a Pressure Balance Chamber?
Extensive testing by Litre Meter in 2005 proved that leaks occur over the top of the rotor at higher pressures. This is due to minute distortions of the cap. For example, at 700 bar, the cap moves by just 0.02mm in the centre. Increasing the bulk of the cap still produces this movement. The effect on flow meter performance was the creation of a leak path for fluid that avoided the positive displacement of the rotor.
The effect was equivalent to about a 3% inaccuracy at 700 bar. As a result of this, Litre Meter designed a pressure balance chamber for its VFF flow meters so it could operate at extreme pressure and low flow rates.
The pressure balance chamber acts as a barrier, protecting the internal measurement components of the instrument from the high pressure conditions, preventing them from expanding and contracting under immense pressure. No distortion means accurate measurement at any pressure. All VFFs are fitted with this technology, identified by the letters PBC in the calibration certificate.
Fluids and Ranges
The VFF has successfully metered fluids such as oils, hydraulic fluids, corrosion, wax, demulsifier, pour point depressant, scale, hydrate inhibitors, biocides and oxygen scavengers for almost 40 years. Flow meter bodies are produced in a variety of high grade materials which offer good chemical and environmental resistance. Applications for flow rates as low as 0.00013 litres/min (0.19 litres/day) have been metered within the off-shore oil industry. The VFF flow meter provides exceptional rangeability with potential turndowns of up to 3000:1, dependent on operating viscosity.
The meters range in size from the smallest standard stock size, LF03 – 18 L/Hr max, to the largest HF40 – 40 L/min maximum. Higher flow-rate flow meters are available to special order. An extensive range of flow meter designs and materials offers pressure ratings to 20,000 psi (1,380 bar). Higher pressure rating designs are offered up to 2,500 bar (36,000 psi). 20,000 psi designs are available, as standard, up to 40 L/min and special designs can measure higher flow rates.
All VFF flow meters are custom calibrated across the customer specified min – max flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity. We can offer meters that range from 0.005 L/hr to 3,600 L/hr at 20 ksi pressures to best suit your applications and with exceptional turndowns.
• No distortion of the chamber at higher pressures
• Enables selection of optimal materials for the chamber to match the rotor i.e. PVD coated stainless steel or titanium
• Enables selection of optimal materials for the pressure vessel
• Enables construction of a duplex bodied flow meter
• Interchangeable PBC for simplified sparing
• Calibration can be performed at low pressure
The VFF meter is not just one size, one specification. It’s a comprehensive range of carefully engineered devices to meet today’s standards in the most demanding oil & gas arenas. It truly is a Versatile Fluids Flow Meter. The smallest flow meter suitable for high pressure is typically housing an LF03, LF05 or LF15 rotor and chamber with FlowPod instrument and Autoclave Engineers MP connections. Then there is a medium size meter such as the VFF4, with special hub connections and FlowPod display. There is also the flow meter with hubbed connection sizes and FlowPod display, but is larger to accommodates the HF40 rotor and chamber.
High Pressure Flow Meters – How Do We Test Them?
At Litre Meter we are industry leaders in producing high pressure flow meters. But how do we ensure the pressures our customers request, can be safely achieved? Pressure Ratings Generally, the pressure ratings for our flowmeters depend on the rating of the connection. Within our standard line of VFF flow meters, we provide “Medium Pressure” […]
Since 1985, we’ve supplied businesses worldwide with a large selection of durable, industry-standard Positive Displacement flow meters. For the last four decades, we’ve built a huge catalogue of products to suit your every need organised by flow ranges – from our standard range of flow meters (popular in the UK, EU and US), to our […]