We’ve noticed a trend in Chemical Injection Flowmeters
Over the last year we have seen an increase in V125 flowmeter sales. Our CEO Charles Wemyss takes a closer look at the flowmeter normally used in chemical injection applications.
Litre Meter’s VFF range
Our range of VFF sizes goes from the very lowest flows in the industry – just a few millilitres per hour – up to several hundred litres per minute. We usually look to our smallest devices, the LF series which includes the LF03, LF05 and LF15, to be the most popular. Last year the V125 saw a steady increase in sales. The V125 is a big flowmeter by comparison. It’s number relates to 125 which is it’s maximum rated flow in litres per minute. Rather than the compact LF series which are usually under 8kg the V125 can need a crane to move it at higher specifications.
So why is this, what’s the driver behind this?
The usual uses of the VFF is for chemical injection. Most times, it is for inhibitors that are injected into the oil at very low flow rates, say 0.1 to 10 l/h and a bit lower and a bit higher. The LF range normally covers it.
To prevent freezing of the crude a hydrate inhibitor is added. The name of the liquid is often abbreviated to LDHI or Low Dosage Hydrate Inhibitor. Alternatively, methanol is added. Typical flow rates are 10, 20 or 25 US gpm.
The pressure at which they are injected must be greater than the oil pressure. For ultra-deep installations pressures can exceed 690 bar or 1035 bar. Recent meters have been specified at 20k(si) or 20,000psi/1380bar.
High pressure flow meter
It’s this combination of high flow rate and high pressure that produces some special challenges. Litre Meter are in a unique position with the VFF range where the measurement is independent of pressure rating or operating pressure. A vessel is designed to withstand the pressure and a pressure balanced measuring chamber is at its heart. All of the V125s are made in this way. It’s the same technology and instrumentation for all meter sizes so making an attractive proposition for simple installation, design and maintenance in a chemical injection skid.
V125 Technical Specification
Meter size: V125
Technology: Rotary Piston, positive displacement
Flow Range: 100 to 7500 l/hr on 4cSt, typical
Pressure Rating: 208 bar, 345 bar up to 690 bar, 1035 bar and 1380 bar depending on material and connection selection
End Connections: Threaded, 3/4 or 1″NPT, Grayloc hubs such as 1GR7, 3GR25, Techlok hubs 2IN14 and wafer 1″ANSI2500, 2″2500
Materials: 316L SS, Duplex, Super Duplex, Titanium to specification
Fluids: Typically methanol, LDHI but also HW740R and Sodium Hypochlorite
Pulsing Flow: Acceptable. The nature of positive displacement flow measurement means it is immune from pulsing flow effects that can skew other meter technologies.