In the chemical injection arena, it is common to inject sodium hypochlorite into sea water. Sea water can contain dissolved oxygen, bacteria and solids. These can affect an oil reservoirs life. Hypo is used as a bactericide. Hypo is aggressive before it is diluted in the sea water and therefore requires some specialized devices and wetted materials. Litre Meter have been manufacturing flowmeters since 1975. Litre Meter has two solutions to this application for flows from 0.5 l/hr. The VFF rotary piston positive displacement flowmeter is constructed in titanium or Hastelloy. It is hazardous area approved as standard. The Litre Meter Pelton Wheel flowmeter is constructed in PVC with a variety of sensors and displays for safe and hazardous areas. In summary, a flowmeter can be selected that handles any concentration of NaOCl and provides a display and/or output for measurement and control.
Positive displacement flowmeters, also known as PD meters, measure volumes of fluid flowing through by counting repeatedly the filling and discharging of known fixed volumes. A typical positive displacement flowmeter comprises a chamber that obstructs the flow. Inside the chamber, a rotating/reciprocating mechanical unit is placed to create fixed-volume discrete parcels from the passing fluid. In the VFF the rotor is basically a disc shape with an annular groove on its underside capable of holding and transporting flow from the chamber inlet to the outlet i.e. a rotary piston. The units are manufactured in 316 stainless steel or titanium. They can measure pulsing flows. Suitable for potable and sea water. 0.01 to 33,000 l/hr. +/-0.5% accuracy, +/-0.25% repeatability.
Also known as a radial turbine the highly efficient Pelton Wheel meter has some major advantages. The very large blade area compared with the flow inlet port size produces an exceptionally wide range flowmeter which can measure very low flows. The flow through the inlet of the meter is accurately directed onto the rotor which rotates at a speed in linear proportion to the flow rate. A small sensing coil detects the ferrites mounted in the flow meter rotor blade tips as they pass. No drag is imposed on the rotor which assists in the measurement of extremely low flows. Sapphire bearings provide a very low friction mechanically-robust bearing with long life characteristics. Turndown can be as high as 280:1. Ideally suited for water measurement up to 2" pipe sizes and larger and up to 10cSt. 0.003 to 500 l/min; ±2.0% of reading (also 1.0%); some models suitable for flow measurement at higher pressure. Titanium parts can be used where 316 may be deemed inappropriate such as for low velocity areas.
Ultrasonic flowmeters measure the travelling times (transit time models) or the frequency shifts (Doppler models) of ultrasonic waves in a pre-configured acoustic field that the flow is passing through to determine the flow velocity. The Sierra range of ultrasonic (transit time) Innovasonic devices are available, click for details. Litre Meter has access to other ranges but the Innovasonic is relatively unique as not only are fixed and portable ultrasonics available but also insertion devices for tougher applications. Ultrasonic flow meters can measure water and other liquids over a range of velocities and with a certain amount of solid content. 25mm to 10000mm;±1.0% of reading (also 0.5%); 0 to ±40 ft/s (0 to ±12 m/s).