Litre Meter LF Positive Displacement Flowmeter

Description

The Litre Meter VFF has successfully metered for over 35 years fluids such as oils, hydraulic fluids, corrosion/wax/scale/hydrate inhibitors, biocides, oxygen scavengers, etc. Meter bodies are produced in a variety of high-grade materials that offer good chemical and environmental resistance.

The Litre Meter VFF 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. Some fluid is also transported in a cavity formed between the rotor outside wall and the chamber wall. A center ‘peg’ under the rotor is constrained to run in a circular groove in the body. A web (or plate) in the body is engaged with a slot in the rotor and this modifies the rotation to that of an oscillation as the flow passes.

It is this oscillation that produces the compartmentation of the fluid into ‘positively displaced pockets’. The top of the rotor is equipped with a powerful magnet directly above the ‘peg’ that is on the underside. So this also has a circular path that allows it to engage and disengage a reed switch sensor located in the top cap above.

Applications for flow rates as low as 0.000083 liter/ min (0.12 liters/day) have been metered within the off-shore oil industry. The Litre Meter 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 V270 – 270 L/min max. Higher flow-rate meters are available to special orders. An extensive range of meter construction offers pressure ratings from 0 to 1380 bar (20,000 psi) suitable for most industrial applications and special higher pressure rating designs are manufactured up to 4000 bar

Litre Meter LF Flow Meter Litre was introduced as our smallest meter in 2003 and was originally rated to 1.5 l/min (hence LF15). The LF05 joined the family in 2012 and is a third of the size. The LF03 is the smallest of the LF range and is a fifth of the size. Although internally they vary, the external chamber size is identical enabling interchangeability. Flows start at 0.005 l/hr (0.00008 l/min, 0.001 GPH).

Benefit

• No distortion of the chamber at higher pressures
• No measurement inaccuracy due to pressure
• Enables selection of optimal materials for the chamber to match the rotor
• PVD-coated stainless steel
• Enables selection of optimal materials for the pressure vessel. i.e. super duplex stainless steel
• Enables construction of a duplex bodied flow meter – duplex material does not lend itself to the tolerances required in machining

Features

• Compact
• No straight lengths
• Very Low Flow Measurement
• Tolerant of particulate up to 100+ microns
• Low-pressure drop (<0.1 bar typical)
• Single Moving Part
• Large Viscosity range, from methanol upwards
• Measures pulsing flow accurately
• Preserves Molecular Integrity of fluid
• Pressure independent measurement
• Ultra High-Pressure Capability
• (60,000psi, 4000bar if required)
• Low Maintenance
• Highly Durable

Litre Meter LF Typical Applications

• Chemical Injection
• Corrosion Inhibitor
• Scale Inhibitor
• Subsea Control Fluid
• Subsea flow
• Wax Dispersant
• PIB
• Ashalphtene Dispersant

Characteristic

• Rotary Piston/ Oscillating Piston type flow meter with a single moving part provides robust and low maintenance technology.
• Suitable for low & high-viscosity liquids at pressure ratings up to 4,000 bar (60,000 psi).
• Available materials of construction: 316L, Duplex F51(UNS S31803), Super Duplex F53(UNS S32750)/ F55(UNS S32760). 6Mo F44(UNS S31254),  Hastelloy (UNSN10276) & Titanium (UNS R50400 or R56400).
• Connections: NPT, Autoclave, ANSI & API flanges, Grayloc Hubs, Galperti Hubs, Techlok hubs. More on request.
• Communications: 4-20mA HART, Pulse, MODBUS, Foundation Fieldbus. Dependent on electronics and certification requirements.

Litre Meter LF Positive Displacement Flow sensor

Technical Specifications LF range

Interchangeable PBC between LF03, LF05, and LF15. Different rated chambers can be retrofitted as field demands change.

Internals:

• These are constructed in either Nitronic-60 (anti-galling) or Titanium for the LF03, LF05 & LF15 sizes to achieve the lowest flow and widest turndown possible. Chambers and rotors are PVD-coated. Coatings are applied by physical vapor deposition. A hard metal chromium nitride base layer provides surface hardness and appropriate support for the carbon (WC/C) which is laid over.
• The WC/C coating provides excellent protection against adhesive wear and its low coefficient of friction reduces the risk of surface fatigue (pitting) and fretting corrosion, vastly improving turndown and low flow capability.

Seal:

• There are pressure seals between the meter body and cap as well as the internal chamber. The seals are available in FPM, FFKM, FEP covered silicon and in higher pressure versions PTFE and Inconel. The seals are selected based on pressure and fluid to optimize the full use of the meter.

Connections:

• NPT threaded connections are standard for lower-pressure versions, and Autoclave Medium Pressure fittings (cone & thread) are standard for higher ratings. ANSI & API flanges in the raised face and ring-type joint are also available. Hubs such as Grayloc, Galperti, Techlok are
  available as standard designs

Sensor:

• Two reed switches in one single compact sensor housing that can be set for reverse flow detection or redundancy and tested for over 1 billion pulses.
  • Accuracy: ±1.0% of reading
  • Linearity: ±0.5% of reading
  • Repeatability: ±0.1% of reading
  • Viscosity: 0.5 – 100,000 CST or greater.

Temperature rating:  -40°C – 100°C with remote-mounted electronics. For direct mount, versions see the next page. Higher temperature special versions are available on request.

Filtration:  A 100-micron filter is advisable for 100% long-life serviceability. For LF03 & LF05 size a 40-micron filter is recommended

Litre Meter Electronics & Instrumentation

Litre Meter offers a wide range of safe area and hazardous area displays and instrumentation for use with the VFF flowmeter to suit all needs.

Flowood: Flow Transmitter

The direct or remote-mounted FlowPod instrument provides local display indication in an enclosure that is only 85mm in diameter with large rate and totalizer digits, backlit in the 4-wire Exd version.

The Flowood comes complete with programmable card input to enable calibration data to be swapped without having to remove from
the installation and to enable data logging. The Flowood comes as standard with HART 7 protocol output on a two or four-wire 24 Vdc powered system.

Key Features:

• Material: 316 SS Enclosure Housing
  • Exd- CSA(US): Class1 Div1 (B,C,D)
  • CSA(CAN): Class1 Div1 (B, C,D)
  • ATEX: Ex DB IIC
  • IECEX: Ex DB IIC
• Output: 2 or 4 wire 4-20mA HART output
• Power: 12 – 30 Vdc
• Ambient Temperature Rating: ?20 to +75°C
• Protection class: IP66/IP68 dual certified

VRC: Flow Transmitter

• Compact local display for safe areas or Exia applications with aluminum housing.
• The VRC can be used as a loop-powered 4?20mA unit (2-wire operation) and has a graphic display showing the rate and total.
• HART is an optional extra.
• Material: Aluminum Chassis
• Safe area or ATEX Exia (ATEX II 2G Ex ia IIC T4 Gb)
• 2 wire 4-20mA HART output (HART is optional)
• Power: 15 – 30 Vdc, can be loop powered
• Temperature Rating: ?20 to +120°C
• Protection class: IP 65
• Can be programmed with up to 3 different calibration curves

F – Series Fluidwell Flow Transmitter

• Compact local or direct mounted display for a safe area or Exia applications.
• The F Series is a local indicator that displays the actual flow rate, total, and non-resettable accumulated total.
• Available in a wide variety of power, output, and enclosure configurations.
• Material: GRP or Aluminium
• Safe area or ATEX / IECEX / FM / CSA Exia
• 2 wire 4-20mA HART output (HART is optional)
• Power: Battery or Loop Powered
• Temperature Rating: ?40 to +70°C
• Protection class: IP 67

Calibration

All VFF flowmeters are custom calibrated across the customer-specified minimum – maximum flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity. To see the achievable calibration ranges for each meter size.

Reference: litremeter.com

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