What’s in a typical flow meter datasheet?

First, let’s have a look at what might land on your desk.  Later, we’ll review it line by line. Sign up for FlowSight, the Litre Meter newsletter.

A typical datasheet relating to a flowmeter is given as below – this one is based on a NORSOK format:

Flowmeter datasheet – Norsok layout.

This one is for the same meter but based on an ISA format (a version used by Litre Meter which uses S20.25 as it’s base):

Flowmeter datasheet – ISA layout, describing the same flowmeter.

Norsok:

This is an approximate layout, typified by NORSOK.

1 General

1.01 Type – a description of the flowmeter, by trade name and basic principle

1.02 Manufacturer – manufacturer’s name.

1.03 Design Temperature Limits – maximum and minimum design temperatures in suitable temperature units (°C)

1.04 Design Pressure Limits – maximum and minimum design pressures in suitable pressure units (bar gauge)

1.05 Estimated Pressure Loss – pressure drop at a specific flow such as maximum in suitable units (millibar)

1.07 Face to face dimension – complete assembly length in millimetres, with a tolerance

1.08 Mounting – type of mounting, in this case, In-Line but could be insertion, clamp-on etc.

1.09 Weight – dry, without fluids – in kilogrammes

2 Instrument Characteristics

2.01 Calibrated Range – flow rate range that the unit will be calibrated over – and units

2.02 Characteristic – an appreciation that not all meters are necessarily linear – some are non-linear such as orifice plates where the pressure drop is related to the flow rate by a square law, in this case linear – and linearised.

2.03 Meter factor – an estimated value of the number of pulses per litre – or other volume or mass unit

2.04 Accuracy – with percentage bounds and either proportional to the actual reading or FSD (Full Scale Deflection)

2.05 Linearity – with percentage bounds and either proportional to the actual reading or FSD (Full Scale Deflection)

2.06 Repeatability – with percentage bounds and proportional to the actual reading

2.07 Max Range limit – not necessarily the same as the maximum calibrated flow – describes the capabilities of the flowmeter

3 Meter Body

3.01 Nominal Size – normally relating the meter body size to the pipe size

3.02 Manufacturer model number – to precisely define the scope of supply

3.03 Process connection size and type – Size and flange or thread type, for example

3.04 Pressure rating – the rating of the flowmeter body in comparable units to 1.04

3.05 Face to face dimension – will match 1.07 in most cases

3.06 Body inner diameter – where appropriate

3.07 Sour service specification – nominated when appropriate – ISO or NACE in this example

3.08 Material, body – A specification for the material of the flowmeter body i.e. the main part of the meter

3.09 Material, Raised –

3.10 Protective coating/color

3.11 Other

4 INTERNAL

4.01 Type – such as rotor and chamber or another description of the flowmeter internals and principle

4.02 Material, shaft – if any

4.03 Material, support – if any – this might refer to a turbine flowmeter part

4.04 Material, rotor

4.05 Material, bearing – if any, may include material and type

4.06 Material, Seal – not just the materials but may include seal type

4.07 Material, pick-up – i.e. sensor material, wetted, or not

4.08 No of pick-ups

4.09 Other

5 FLOW STRAIGHTENER

5.01 Type

5.02 Material

5.03 Connection

5.04 Other

6 METER TUBE

6.01 Material

6.02 Connection up/downstr.

6.03 Up/downstream length

6.04 Tube inner diameter

6.05 Other

7 STRAINER

7.01 Type

7.02 Body/mesh material

7.03 Connection

7.04 Other

8              TRANSMITTER

8.01        Manufacturer model no

8.02        Mounting

8.03        Max distance meter/trans

8.04        Cable connection

8.05        Cable entry

8.06        Dimension

8.07        Material

8.08        Enclosure protection

8.09        Ex. classification

8.10        Protective coating

8.11        Indicator

8.12        Tamb

8.13        Totalizer

8.14        Output signal (note 9.02)

8.15        Communication

8.16        Recommended loop voltage

8.17        Transmitter loop voltage drop

8.18        Max loop current (fault condition)

8.19        Other – in this case describes more of the hazardous area ratings and standards – CSA, IECEx and ATEX

Measuring Sodium Hypochlorite in Hazardous Areas

Sodium Hypochlorite

Sodium hypochlorite is a green/yellow liquid with the characteristic smell of chlorine. It was first used as a bleaching agent and was then discovered to be effective in controlling wound infections. Subsequently, it is most commonly known as household bleach. The solution exhibits broad spectrum anti‐microbial activity and is widely used in healthcare facilities in a variety of settings. It is usually diluted in water depending on its intended use. Sign up for FlowSight, the Litre Meter newsletter.
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 whilst filters take care of the solids. Hypo is aggressive before it is diluted in the sea water and therefore requires some specialized devices in terms of wetted materials. Litre Meter have been manufacturing flowmeters since 1975.
We’ve always concentrated on the harder margins of metering typically at low flows and/or at high pressure. For this application note Litre Meter illustrate two solutions to this application based on <20 % solution. Download brochure.

Sodium Hypochlorite Flowmeters ‐ Applications and Rates ‐ VFF

The VFF has successfully metered fluids such as oils, hydraulic fluids, corrosion / wax / demulsifier / pour point dispenser /scale / hydrate inhibitors, biocides, oxygen scavengers, etc. for over 30 years. Meter bodies are produced in a variety of high grade materials which offer good chemical and environmental resistance. For sodium hypochlorite, Litre Meter recommend Titanium for the body and chamber with carbon graphite for the actual rotary piston. This ensures maximum compatibility, life and accurate response. The magnet is either encapsulated in titanium or PTFE.

VFF Flowmeter Sizes and Connections.

Applications for flow‐rates as low as 0.5 litres per hour have been supplied. Normal minimum flow rates depend on operating viscosity. In this case, viscosity is assumed to be between 1 and 2.5cP. Using the smallest VFF with carbon graphite rotor (LF15) and calibrating on water, which has a lower viscosity than NaOCl, a range of 0.5 to 40 L/hr is achieved. The meters range in size from the smallest titanium body, LF15 – 40 L/hr, to the largest V270 ‐ 270 L/min max. Higher flow‐rate meters are available to special order. The table at the end of this article assists in the selection of the best technology.

Sodium Hypochlorite Flowmeters ‐ Applications and Rates ‐ Pelton Wheel

Litre Meter started manufacturing the Pelton Wheel turbine in 1975. These usually had some stainless steel components together with a plastic rotor, elastomer seals and sapphire bearings. All plastic versions soon followed, including all Polypropylene, all PFA, all PVC and all PVDF. The other wetted parts are still sapphire with a suitable elastomer such as FKM or FFKM for the single O ring seal. The normal specification for Sodium Hypochlorite compatible Pelton Wheel flow meters is now PVC for the main body and cap with PVC or titanium internals, sapphire bearings, an FKM O‐ring and PFA rotor.

Pelton Wheel Flowmeter for Sodium Hypochlorite

The Pelton Wheel is an economical device with low pressure ratings and needs to have relatively steady state non‐pulsing flows.
The table at the end of this article assists in the selection of the best technology.

Compatible Materials

Due to the nature of Sodium Hypochlorite only a select group of tested materials is recommended by Litre Meter. We tailor our meters using three key materials, developed over 30 years of measuring Sodium Hypochlorite:

PVC, Hastelloy and titanium
The PVC design can be used up to 15 bar pressure maximum. Hastelloy (UNS N10276) up to 1035 bar. For the ultimate select titanium (UNS R50400) designed for 1380 bar (20,000psi, 20 ksi)

These material make up the body and the cap of the meter. The seals between the meter body and cap are normally FKM. Other seal materials include FFKM and PTFE. All seals within the meter are fully compatible with Sodium Hypochlorite.

Flow ranges and references

All Litre Meter manufactured flowmeters are custom calibrated across the customer specified minimum to maximum flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity. With sodium hypochlorite, in most normal concentrations, water is used as the calibration medium as this proves to be the best for accurate calibration representation. The table below assists in selecting which technology is preferred.
Normal engineering materials like 304 and 316 stainless steel, aluminium, brass and steel are unsuitable due to the aggressive nature of the free chlorine in the Sodium Hypochlorite. Plastics such as PVC and PTFE are suitable together with Hastelloy C and purer grades of Titanium.

Comparison table:
Table showing selection criteria for Sodium Hypochlorite meters in two different flow technologies.

Why should I measure Scale Inhibitor (and how)?

Money, money, money – or, as we now call it, Flow Assurance, coupled with a low flow meter

Allowing scale to build up on the inside of the pipeline may seem fairly inconsequential. However, when the amount of scale is considered, (and referencing the image) it is immediately obvious that the expensive crude will slow down and pumping costs will soar. Sign up for FlowSight, the Litre Meter newsletter.
Scaling reduces the area of a pipe if scale inhibitor is not used
Scaling reduces the area of a pipe if scale inhibitor is not used – Stock image
Chemists will analyse the crude oil as it comes out of the well, sometimes years before production starts. From geotechnical surveys other technicians will determine the rate of oil output through the anticipated life of the field.  With this data the chemist will recommend what the concentration of the scale inhibitor should be.  The pressure of the well will determine at which pressure the inhibitor needs to be injected at. Day to day the temperature will vary according to the seasons, the weather and location of the measurement.
The analysis of the crude, unrefined oil will tell the chemist whether the pipe will start to scale up as a result of pumping the oil through a pipe to the ship or refinery.  Certain chemicals are then formulated to optimise and negate the scale.  There will be compromises between concentration of the fluid, application flow rates and storage availability.  If the concentration can be increased so that the tanks only need filling up once per month then that is preferred to once per fortnight. Inevitably this means that the flow rate is lower, and probably, the viscosity increases. Measurement range will also vary through the life of the field. It may start slow, then plateau a few years later and then tail off as the field winds down.  Additionally to this, the consistency of the unrefined oil will probably change from start to finish.  All of these variables can lead to a range of viscosities and a range of flow rates.
In summary, selection of the meter philosophy and specification is critical to successful measurement of scale inhibitor and future condition of the oil pipeline.

The VFF rotary piston flowmeter has been used for many years to measure scale inhibitor at a variety of flow rates, pressures and viscosities.

VFF flowmeter for chemical injection service, with FlowPod display

Flowmeters for Sodium Hypochlorite – Hazardous Area, too

Sodium hypochlorite

Sodium hypochlorite is a green/yellow liquid with the characteristic smell of chlorine. It was first used as a bleaching agent and was then discovered to be effective in controlling wound infections. Subsequently, it is most commonly known as household bleach. The solution exhibits broad spectrum anti‐microbial activity and is widely used in healthcare facilities in a variety of settings. It is usually diluted in water depending on its intended use.
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 whilst filters take care of the solids. Hypo is aggressive before it is diluted in the sea water and therefore requires some specialized devices in terms of wetted materials.
Litre Meter have been manufacturing flowmeters since 1975.
We’ve always concentrated on the harder margins of metering typically at low flows and/or at high pressure. For this application note Litre Meter illustrate two solutions to this application based on <20 % solution.

Sodium Hypochlorite Flowmeters ‐ Applications and Rates ‐ VFF

The VFF has successfully metered fluids such as oils, hydraulic fluids, corrosion / wax / demulsifier / pour point dispenser /scale / hydrate inhibitors, biocides, oxygen scavengers, etc. for over 30 years. Meter bodies are produced in a variety of high grade materials which offer good chemical and environmental resistance. For sodium hypochlorite, Litre Meter recommend Titanium for the body and chamber with carbon graphite for the actual rotary piston. This ensures maximum compatibility, life and accurate response. The magnet is either encapsulated in titanium or PTFE.
Applications for flow‐rates as low as 0.5 litres per hour have been supplied. Normal minimum flow rates depend on operating viscosity. In this case, viscosity is assumed to be between 1 and 2.5cP. Using the smallest VFF with carbon graphite rotor (LF15) and calibrating on water, which has a lower viscosity than NaOCl, a range of 0.5 to 40 L/hr is achieved.
The meters range in size from the smallest titanium body, LF15 – 40 L/hr, to the largest V270 ‐ 270 L/min max. Higher flow‐rate meters are available to special order. The table on the last page assists in the selection of the best technology.

Sodium Hypochlorite Flowmeters ‐ Applications and Rates ‐ Pelton Wheel

Pelton Wheel Flowmeter for Sodium Hypochlorite

Litre Meter started manufacturing the Pelton Wheel turbine in 1975. These usually had some stainless steel components together with a plastic rotor, elastomer seals and sapphire bearings. All plastic versions soon followed, including all Polypropylene, all PFA, all PVC and all PVDF. The other wetted parts are still sapphire with a suitable elastomer such as FKM or FFKM for the single O ring seal.
The normal specification for Sodium Hypochlorite compatible Pelton Wheel flow meters is now PVC for the main body and cap with PVC or titanium internals, sapphire bearings, an FKM O‐ring and PFA rotor.
The Pelton Wheel is an economical device with low pressure ratings and needs to have relatively steady state non‐pulsing flows.
The table on the last page assists in the selection of the best technology.

Compatible Materials

Due to the nature of Sodium Hypochlorite only a select group of tested materials is recommended by Litre Meter. We tailor our meters using three key materials, developed over 30 years of measuring Sodium Hypochlorite:

These material make up the body and the cap of the meter. The seals between the meter body and cap are normally FKM. Other seal materials include FFKM and PTFE. All Seals within the meter are fully compatible with Sodium Hypochlorite.

Flow ranges and references

All Litre Meter manufactured flowmeters are custom calibrated across the customer specified minimum to maximum flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity. With sodium hypochlorite, in most normal concentrations, water is used as the calibration medium as this proves to be the best for accurate calibration representation. The table below assists in selecting which technology is preferred.
Normal engineering materials like 304 and 316 stainless steel, aluminium, brass and steel are unsuitable due to the aggressive nature of the free chlorine in the Sodium Hypochlorite. Plastics such as PVC and PTFE are suitable together with Hastelloy C and purer grades of Titanium.

Comparison Table:

Table showing selection criteria for Sodium Hypochlorite meters in two different flow technologies.

Litre Meter can provide optimum solutions for a wide range of flow rates of Sodium Hypochlorite. Using a variety of materials, a flowmeter can be constructed that handles any specific concentration of NaOCl and provide a display and/or output for measurement and control. For references etc please download our brochure.