0191 5131313 | hello@siris.co.uk
0191 5131313 | hello@siris.co.uk

siris2021

PROJECTS CO-ORDINATOR

£25,000 to £32,000 depending on experience

We are looking for an enthusiastic Projects Co-ordinator to join the SIRIS family.  

 

Are you well organised, great at self-management and able to manage multiple projects with conflicting priorities? 

 

Do you have an appetite to learn about new equipment and technologies?

 

If the answer to the questions above is YES, then we want to hear from you!

About us:

Siris Environmental is a Washington-based company providing our industrial and water utility customers with the best possible effluent flow monitoring solutions.

 

We work with private organisations and water companies across the UK, ranging from small trade effluent customers to large-scale factories and water companies, and have built a reputation for providing high quality service, delivered by a passionate team. 

 

Now has never been a more exciting time to join us. We are growing rapidly and have plenty of exciting opportunities for the right person to join our team. If you are energetic, hands-on, innovative, and professional, this is the environment for you.

What will you be doing?

You’ll be joining our services team, based in our Washington HQ workshop and with some travel to sites across the UK.

 

You will act as a bridge between our admin and field teams, assisting our service and MCERTS teams.

 

Your role will primarily be service work, overseeing jobs coming in and out of the workshop, managing our stock holdings and supporting our field-based team. 

 

Requirements

A background in wastewater isn’t essential as we will provide full training to the right person, however we are looking for the following:

  • Experience in a hands-on, technical role 
  • Factory working experience
  • Working knowledge of Microsoft Excel 

Benefits

  • Competitive salary
  • Family-run business feel with big business opportunities
  • Flexible working
  • Ongoing training and development 
  • Prospects for career advancements

Apply now

Sitrans Mag 8000 Manual (FM Mag 8000/Mag 8000 CT) Operating Instructions

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SITRANS MAG 8000 MANUAL ( FM MAG 8000 / MAG 8000 CT)

Offering a flexible and reliable water flow meter, the SITRANS FM MAG 8000 battery-operated water meter is suitable for a variety of locations without compromising on accuracy or performance. 

Benefits

  • Flexible installation – IP68 (NEMA 6P) compliance allows installation in soil or underwater 

  • Low pressure loss and excellent leak detection 

  • Optimised lining allows good metering performance with low flow
  • No maintenance – no moving parts and battery life of up to 15 years
  • Maximum freedom in installations with low inlet and outlet distances

  • Approved for MID-001 without defined length of inlet and outlet 

  • Remote access possible – running flow data through optional wireless 3G / UMTS communication module

Sitrans Mag 8000 manual

The Sitrans Mag 8000 Flow Meter is packed full of features and innovations for optimum performance.

 

  • Battery powered
  • Low maintenance
  • Operates in challenging environments
  • Easy to install with compact and remote versions and 0D inlet/outlet requirements
  • Built to resist solids and other debris in accordance with ISO 12944-2
  • IP68/NEMA 6P enclosure allows installation in flood-prone locations

Download Sitrans Mag 8000 Brochure >

The Siemens product offers accessible data

 

  • High accuracy rate – 0.2%-0.4% flow rate
  • Includes built-in wireless Automated Meter Reading (AMR) for use in Water Fixed Networks
  • Flow measurement data from any site can be accessed via a web browser and secure password protection
  • Remote data monitoring possible through added compact wireless communication module 
  • End user can specify exact times for data transmission, thus allowing synchronisation of multiple devices
Full Operating Instructions Sitrans Mag 8000 Manual Here

WE CAN HELP

For enquiries about this flow meter or any elements of flow meter systems please contact our expert team

CONTACT US

What is the Mogden Formula and why does it matter for trade effluent?

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The Mogden Formula

Calculating Trade Effluent Charges

This rather complex-looking equation represents the key tool in calculating trade effluent charges.  Termed The Mogden Formula after first being adopted at the Mogden Water Works in London, it incorporates a number of variables such as contaminant and suspended solids levels that are used to calculate the final treatment cost per m3 of the effluent. 

 

The formula can be broken down as follows:

 

R = the charge from the water treatment works for receiving and conveying the effluent (in £/m3)

 

V = the charge from the water treatment works for the primary treatment* of the effluent *removal of material that will either float or readily settle out by gravity

(in £/m3)

 

Bv = the charge from the water treatment works for any biological* treatment (in £/m3) *breakdown/decomposition of organic contaminants from the wastewater

 

M = the charge from the water treatment works for the treatment and disposal of any effluent that must go out to sea (in £/m3)

 

B = the charge from the water treatment works for the biological oxidation* of any settled sewage (in £/m3) *B-stage, or bio-oxidation stage, where remaining organic material in low-loaded activated sludge is biodegraded

 

Ot = the chemical oxygen demand (COD) of effluent after one hour of quiescent settlement at pH 7 [mg/litre]

 

Os = the chemical oxygen demand (COD) of effluent after one hour of quiescent settlement [mg/litre]

 

S = the charge from the water treatment works for the treatment and disposal of the primary sewage sludge (in £/kg)

 

St = the total of suspended solids of effluent at pH7 (in mg/litre)

 

Ss = the total of suspended solids of effluent (in mg/litre)

what is the mogden formula

The more contaminants and suspended solids in the wastewater or effluent, the more expensive it will be to treat and dispose of.  This is known as The Trade Effluent Charge and is charged by the local water company to cover costs associated with the transportation, treatment and disposal of the effluent.

 

Many companies use water as part of their processing, such as produce cleaning or cooling, and understanding your Mogden formula can help identify areas to reduce wastewater processing charges.  Essentially there are two ways to do this:

 

–       Reduce the levels of contaminants/solids within the effluent

–       Reduce the volume of effluent

Water companies will issue licences of “Consent to discharge trade effluent” to those companies producing effluent for public disposal, which will outline specific conditions and charges for your licence.  The consent licence will stipulate how the wastewater must be monitored (or measured).  Sometimes this will be through self-monitoring but the water company may also routinely monitor flow and composition of the effluent to ensure compliance and estimate charges.   Water companies may vary in their application of the Mogden formula, but this information will be publicly displayed on their website, in line with the OFWAT regulator. 

 

Having an accurate and reliable picture of your effluent data is therefore key in ensuring the correct charges are being paid, as well as understanding where costs are coming from within the variables.  This is done via two primary methods – wastewater sampling and wastewater flow measurement. 

A Siris Effluent Sampler
THE MOGDEN FORMULA IN PRACTICE

Role of Effluent Sampling

An accurate base for calculations

Effluent sampling ensures the accurate measurement of those variables used within the Mogden formula.  Without them, calculations may be based on estimates, which could be bringing unnecessary additional charges to the business.

Investing in an approved, on-site wastewater sampling system gives more comprehensive and ongoing accurate data that can be used to monitor the quality of the wastewater discharge on a continual basis, using composite samples to provide data to the EA and local water authorities that can reduce charge liabilities and business costs.

 

At SIRIS we offer a range of MCERTS-accredited wastewater samplers that suit both open channel and closed pipe applications, providing robust and long-lasting sampling solutions for a range of industrial and commercial businesses.  We offer automatic, composite, refrigerated sampling, which ensures regular samples of your effluent at key times e.g. high loads/low loads.  Factors such as this are important and carefully considered in the design and specification of your effluent monitoring system by the SIRIS team.  For example, water company spot samples may focus on times of high contaminant concentration, giving an inaccurate picture of the average effluent strength level and causing unnecessary charges.  The refrigerated element of our samplers ensures that samples do not degrade.,

ACCURATE VOLUME OF FLOW

Role of Flow Measurement

Ensure a true picture of volume of effluent

 

Measurement of volume of flow is another critical data point in which to ensure accuracy.  Again, on-the-spot water company measurements can give biased flow volumes, for example if these were taken only during high production points on the plant. 

 

Our solutions ensure an accurate picture of flow volume over time.  Depending on the specific business type and requirements, effluent flow may be measured on either an instantaneous or continuous basis, each of which requires careful specification of equipment. At SIRIS, our experienced approach to effluent flow measurement allows us to specify and develop robust and reliable measurement systems.

Learn how we saved one client over £170,000 through accurate effluent monitoring

WE CAN HELP

For any queries or assistance with your trade effluent sampling or flow measurement, please contact our expert installations project team, who are set to help with any effluent challenge.

CONTACT US

Proud to be supply chain partner of award-winning Wolsingham Sewage Treatment Works Growth Improvement Project

SIRIS proud to be supply chain partner of award-winning Wolsingham Sewage Treatment Works Growth Improvement Project

The whole projects team at SIRIS is proud to have been a recognised supply chain partner in the award-winning Wolsingham Sewage Treatment Works (STW) Growth Improvement Project.  Completed in 2021 during the height of the pandemic, the £6m project has been awarded Civils Project of the Year in the Constructing Excellence in the North East Awards.

Led by Tilbury Douglas (contractor) and Wood (designer) for client Northumbrian Water, the project was recognised for its use of new technology, implementation of off-site, sustainable construction methods and best-in-class collaboration between all project stakeholders

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The Project

An upgrade to tackle increased flows and asset deterioration

The Sewage Treatment Works was in need of an upgrade as demand on the site had increased in line with population growth in the area, estimated at some 19%.  The upgrade project had to identify solutions to the issues caused by increased flows and loads identified at the site and the related impacts on associated sewerage networks.  In addition to this, further work to tackle asset deterioration and ongoing pollution incidents due to sewer overflow was to be incorporated into the project. 

 

The design phase of the project, started in 2018, took an innovative “Off-site by Default” and DfMA (Design for Manufacture and Assembly) approach to build technology, an ethos that was mirrored throughout all phases of the project with the ongoing support of client Northumbrian Water.  The Sewage Treatment Works was consequently able to be built using off-site build methodology, a ground-breaking approach within the water industry. 

This method brought tangible and sizeable benefits to the project in terms of reduced costs, timelines and environmental impact; with some £1m pounds, 4 months and 34 man hours estimated to have been removed from the project initial budgets and timescales. 

 

Northumbrian Water now plans to adopt the new off-site build approach within their AMP7 framework, a real testament to the success of the project and the collaboration of partners and supply chain throughout. 

Picture courtesy of Tilbury Douglas
Early phase drawing of the inlet flume design The inlet flume, manufactured off-site and installed into the inlet works Picture courtesy of Wood https://www.woodplc.com/
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SIRIS FLOW INLET FLUME & WEIR INSTALLATION

Off-site Build Concepts

Working under the brief of design partners, Wood, SIRIS was able to develop off-site build concepts for the inlet of the works, using a prefabricated, above-ground approach.  The inlet-flume design was built offsite within the SIRIS on-site factory, using non-standard GRP-reinforced, welded PVE construction materials to give the increased accuracy and sensitive tolerances expected for MCERTS certification.  The materials also benefited from a service life of up to 50 years.    

Transported in two sections, the inlet flume was installed readily into the SWT without problem, showing the potential for future off-site build methods for installations of this type.

 

 

“The off-site construction nature of this project represented a new approach in the water industry.  With our on-site factory and engineering team, we were able to quickly integrate into the adopted working methods by providing a fully constructed inlet flume and weir system, then transported to and installed on the works site directly.  Our team collaborated fearlessly with the project team to achieve all requirements and we are proud to have been involved in such an innovative development.”

SIMON RICHARDSON
DIRECTOR, SIRIS
Here at SIRIS we are able to work with our clients flexibly and in line with individual project requirements.

Working with varying client types, including water companies and trade customers, we design, construct and install reliable and accurate flow measurement and sampling installations for use with trade effluent and wastewater.

Meet the experts: Jordan Marley

 

We’d like to introduce you to the experts who make up our team here at SIRIS. This month we’re talking to Trainee Servicing & Installation Engineer, Jordan Marley.

 

What is your background and how did you start working at SIRIS?

I left school with better grades than I was expecting and as a result was able to do an electrical engineering course at Sunderland College. Towards the end of the year I had already gained two of the three available qualifications and to get the third I needed to do a week of work experience with an engineering company. Most companies looked the same but one that stood out was SIRIS so I asked my tutor to contact them and see if they’d be willing to offer me a placement which they did! I spent my week learning the ins and outs of what SIRIS do and even got to go on my first ever site visit. The end of the week came, and I’d thoroughly enjoyed my time with the company, so you can imagine how pleased I was a few weeks later when I received a call from Nick offering me a job!

 

My first day was 17/07/17 and almost four years later, I’m still here, still learning and of course still enjoying my work.

 

What does a typical day look like at SIRIS for you?

No two days are ever the same. One day I could be in the workshop building, assembling and programming a flow system to be delivered to a site, and the next I could be on the road travelling to sites all over the country calibrating, servicing and verifying equipment that we have provided them with. I really like the variety and it keeps work enjoyable and interesting.

 

What do you enjoy most about your job?

I love to solve problems! There’s nothing better than visiting a site where a customer is having issues and finding a solution for them, it gives me a huge sense of pride when I’m able to help others out (and of course relief).

 

What’s a favourite project you’ve worked on recently?

I recently carried out an electromagnetic flow meter installation with fellow engineer Lee Smith for a water company. It was a really challenging job as we had to remove the old broken flow meter and then refit the one into an extremely deep and, as you can imagine, not very spacious, confined space. It was tough and it took us all day to do, so it was really satisfying to see when the flow reading showed up on the transmitter. A challenging, but great day’s work.

 

What do you get up to outside of SIRIS?

I’m an avid Sunderland supporter and have been a season card holder for more than 10 years now (someone’s got to do it!)

 

I’ve only been to one game in the last year and a half due to the pandemic so I’m really looking forward to next season when I can hopefully get back to the Stadium of Light. I’m currently missing the feeling of coming in on a Monday morning when Sunderland have won and Newcastle, who Karl supports, have lost. Other than this I love to travel and spend time with my family and friends.

What is Event Duration Monitoring (EDM)?

Event Duration Monitoring (EDM) helps ensure sewage treatment works (STW) are sticking to their permitted discharge limits. When combined with flow to full treatment monitoring it provides an accurate picture of where flow is going when a STW is at full capacity. In this guide we explain what it means, why it’s important and how to implement it. 

 

What is Event Duration Monitoring and why is it important?

When we talk about an “event” in flow measurement terms, we’re referring to an adverse weather event, typically a storm, that increases the amount of flow going through a sewage treatment works.

 

In simple terms, Event Duration Monitoring allows a treatment works to monitor whether or not an event is happening, and how long it lasts.

 

This is important because an STW has a maximum limit it is permitted to treat, known as flow to full treatment (FFT). This is based on a calculation, normally three times the maximum dry weather flow (DWF). Anything exceeding this amount when storm event occurs is permitted to overflow to storm management systems, or be discharged to a river.

 

The problem arises when a works discharges to storm management before its maximum limit is reached, as this is a breach of its permit and illegal.

 

The Environment Agency’s U_MON3 driver requires water companies to install EDM monitoring by 2025, and more recently the Government announced further measures to ensure STWs are not relying on storm overflows outside of storm events.

 

What does the Environment Agency say?

In 2018, the Environment Agency announced a series of measures designed to better monitor flow to full treatment, which included mention of Event Duration Monitoring:

 

“Install EDM on WwTW overflows to storm tanks at those WwTW where we can’t use existing monitors to be confident that the permitted FFT setting is being complied with.” U_MON3 Driver

 

In a recent report, the EA said it had installed 12,000 monitors by the end of 2020, with installations on remaining sites expected to be completed by 2023.

 

The EA says EDM will give them an accurate picture of how water companies are using their storm overflows and allow them to identify where improvements can be made, take enforcement action where necessary, and ultimately improve water quality.

 

Best practice with Event Duration Monitoring

The EDM device is usually situated immediately upstream of the FFT meter so if any excess flow goes into stream it can record it.

 

Traditionally, the most common way of conducting Event Duration Monitoring is by using a flow measurement device with probes. However, as they are fundamentally contact devices this can cause problems if the probes become damaged or dirty. Careful installation is essential for this type of device because it can be very difficult to reference them against the low point of the weir.

 

A better solution is a non-contact device such as an ultrasonic or radar, installed on a fixed robust bracket that includes a calibration reference point and correctly referenced against the spill height. With care, this should be able to be undertaken within +/- 2mm.

 

As with any flow measurement device, EDM needs to be set up and calibrated by a qualified MCERTS inspector to ensure it doesn’t trigger too early or not at all.

 

Talk to us about Event Duration Monitoring

To find out more about EDM and how we can help, get in touch with our friendly and professional team.

 

Additional resources:

Meet the Experts: Chris Richardson

MEET THE TEAM

Chris Richardson

Your partner in ensuring compliance

We’d like to introduce you to a key member of SIRIS MCERTS Ltd, Chris Richardson, who speaks to us about his role and thoughts on the industry..

 

 

What is your background and how did you start working at SIRIS?

I wasn’t sure what I wanted to do after leaving school and originally went to college to study pre-uniform studies as I fancied being in the police force, possibly in the dog handling department. Unfortunately funding for the course was withdrawn in the second year so I started looking for a job.

 

My Dad, SIRIS founder Nick Richardson, offered me work at SIRIS helping out with flow measurement installations and servicing at sewage treatment works and in the industrial trade wastewater environment.

 

I took a break to spend six months in Spain but ended up returning to SIRIS and have been here ever since!

 

What does a typical day look like at SIRIS?

Every single day is different at SIRIS. Different decisions are required on each and every job or enquiry which comes in, which keeps you on your toes.

 

What do you enjoy most about your job?

I love the satisfaction I get from seeing a project through from initial enquiry to completion, and of course its always nice to receive positive feedback.

 

What’s a favourite project you’ve worked on recently?

I really enjoyed working on a recent project at Cummins Engines, based in Darlington. This was quite a complex job, due to the limitations of the area the customer had available on site. We ended up getting fantastic feedback which was great.

 

What do you think are some of the biggest challenges or opportunities facing the industry at the moment?

Environmental pollution is becoming an increasingly bigger issue. This can be seen now throughout social media, televised documentaries and advertisements. The Environment Agency is making a big push for clearing up our rivers, and rightly so.

 

What do you get up to outside of SIRIS?

I’m a huge lover of outdoor pursuits. I took up fly fishing at the age of 12 and even got to represent England in 2016!

Guide to: Partech analytical measurement products

Did you know we’re a sales and service partner for Partech Instruments? Our partnership allows us to offer a range of analytical measurement devices, enhancing our service offering and giving our customers additional wastewater monitoring options.

 

 

About Partech

Founded in 1964, Partech prides itself on providing cost-effective, tailored easy-to-use wastewater measurement solutions – all combined with a high level of customer service and support. The Cornwall-based team deliver their specialist analytical measurement services across the UK wastewater, drinking water and industrial sectors.

 

As sales and service partners, SIRIS is able to supply, install and maintain a range of Partech products and offer ongoing support to our customers.

 

Partech 7300w² Monitor

Part of the WaterWatch² range, the 7300w² Monitor allows for monitoring of a range of values and can comfortably accommodate up to eight sensors, with additional sensors a possibility depending on site capacity.

 

Key features include:

  • Easy to read LCD display, visible even in direct sunlight
  • Large touch buttons with feedback for use with gloves
  • Intuitive menu structure to allow for minimal training and setup
  • Inbuilt customer configurable trending display, allowing easy access to the last 24 hours of data
  • External USB port and data logging function allows users to log and retrieve all stored data for a site in a standard .csv format without the need for specialist SD cards or compatible hardware
  • User-friendly LCD display and
  • Automatic registration and set up of sensors when connected

 

Measurement options

Using the 7300w² Monitor, we can offer the following measurements:

 

Wastewater temperature monitoring

When monitoring final effluent, discharge consents are sometimes waived when the temperature drops to 4ºC. Accurate temperature monitoring using the correct equipment can help avoid regulation issues.

 

The WaterTechw² TMP Sensor can be combined with the WaterWatch 7300w² Monitor to provide highly accurate temperature measurement between -10°C and +80°C with a measurement accuracy of +/- 0.3°C.

 

Turbidity

Turbidity is a measurement of how transparent a liquid is and is considered a good measurement of the quality of water.

 

It’s also a key indicator of how a sewage treatment works is performing as increased turbidity indicates sludge blanket breakthrough, which can be caused by excessive levels of flow or a failure in the treatment process.

 

We can monitoring turbidity using Partech’s TurbiTechw² LS Sensor, which can be combined with the WaterWatch 7300w² Monitor to provide a comprehensive monitoring solution for the levels of turbidity in final effluent.

 

pH monitoring

pH levels are measured on a scale from 1-14, with values below 7 indicating acidity and values above 7 indicating alkalinity. pH is a critical component of wastewater makeup as its value has a direct impact on how it is treated.

 

Even small changes in pH levels can pose serious environmental issues, as they can impact the health of biological systems and chemical dosing required so it’s essential that they are tested using accurate and robust equipment.

 

The WaterTechw² pH8000 pH Sensor uses a flat surfaced electrode to provide highly accurate pH measurements when combined with the WaterWatch 7300w² Monitor.

 

Cloud-logged data

Data collected from the WaterWatch 7300w² Monitor and associated sensors can be combined with our specialist Cloud-based data monitoring system, allowing you to see all the results in one place – with 24/7 access from any location.

 

Data monitoring allows you to gather crucial flow meter data and ensure you are satisfying regulatory compliance for your water authority, as well as environment agencies in both England and Scotland.

 

Talk to us about Partech products

Get in touch with our expert team to find out how you can include Partech products in your wastewater measurement system.

 

Additional Partech resources

What is a weir tank?

What is a weir tank? In this guide we dive into the world of weir tanks – what they are, how they work and why they can be a good flexible flow measurement option. 

 

 

What is a weir tank?

Weir tanks are a cost-effective and easy-to-install flow measurement solution suitable for both above and below ground applications. Combined with an open channel flow meter, they provide a high accuracy flow system that can measure a wide range of flows.

 

How do weir tanks work?

Weir tanks work by placing a fixed obstruction (i.e. a thin plate weir) within the flow of effluent.

 

The weir is located within a chamber of sufficient capacity to enable calm and tranquil conditions within the measurement area. The length width and depth of the chamber are governed by BS/ISO standards and depend upon the maximum flow rate that needs to be measured.

 

The weir is mounted onto the outlet wall of the chamber and the flow spills over the weir. By measuring the upstream depth of liquid discharging over the weir the flow rate can be calculated.

 

Why use a weir tank?

Weir tanks can be useful in applications where flow is above ground and the flow of water is piped above ground. They provide a flexible option that can accurately measure very low flows being discharged from smaller sits.

 

Weir tank systems are not suitable for use where there is a high solids content in the effluent as there is settlement within the measurement chamber requiring maintenance/cleaning, deposits on the weir plate profile can also impact measurement and flow.

 

Case study: Food manufacturer 

This is a great example of a weir tank providing a cost-effective flow measurement solution.

 

The site’s existing wastewater monitoring system wasn’t fit for purpose – it was incorrectly designed for the flow rates being discharged and was costing the manufacturer a great deal of money due to the system reading a flow rate greater than actual.

 

We assessed the site and following discussions with the client on the various options available we recommended an above ground weir system of sufficient capacity to accurately measure the flow rates being discharged. This resulted larger weir chamber giving calm and tranquil flow conditions enabling high accuracy readings.

 

The customer recovered the cost of the installation in reduced charges in less than a year.

 

Read more about this project.

 

SIRIS weir tanks

Our standard weir flow measurement systems cover a wide range of flow rates and can be designed to suit most discharge applications.

 

SIRIS weir tanks are manufactured in rigid PVC and reinforced for maximum rigidity and durability, including two solid external support bands to prevent bowing and distortion, with the inlet and outlet pipes able to be fabricated to suit customer requirements.

 

The system includes provision for a data logging flow meter housed in a weather-proof kiosk, a critical laser-machined thin plate weir, an upstream baffle and a maintenance drain-down valve. In addition, the outlet weir plate has additional supports so it remains free from any bowing or skew.

 

Our weir tanks are pre-calibrated by our experts at our specialist facility, guaranteeing compliance with both BS/ISO 1438 and MCERTS. On-site installation is as simple as connecting the inlet and outlet pipes, powering up and switching on – making it an ideal off-the-shelf solution.

 

Weir tank sizes

Measurements represent internal dimensions. Bespoke weir tanks can be designed to specific client requirements.

 

*Flow ranges for the Siris M & L tanks are dependant upon type of weir plate installed.

 

Talk to the experts

Our team of experts have can offer advice and guidance on the best type of flow measurement system for your requirements, including weir tank sizing. We encourage you to get in touch to find out how we can help on hello@siris.co.uk.

 

Additional resources

Guide to: the electromagnetic flow meter

The electromagnetic flow meter (or ‘magmeter’) is a popular, highly accurate and low maintenance flow measurement option for closed pipe applications. In this guide we explain what they are and how they work. 

 

 

What is an electromagnetic flow meter and how does it work?

Electromagnetic flow meters are of the most widely used wastewater flow measurement options for closed pipe applications due to their high level of accuracy and reliability, when installed and maintained by a qualified engineer. The instruments work by measuring the voltage produced by a conductor (i.e. wastewater) moving through a magnetic field, following the principles of Faraday’s Law.

 

Faraday’s Law

Faraday’s Law of Induction predicts how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF) – a phenomenon known as electromagnetic induction. The more conductive a fluid is the better it will be reflected in the readings, which makes magmeters suitable for wastewater applications. In an electromagnetic flow meter, a magnetic field is generated and channelled into the liquid flowing through the pipe.

 

Faraday’s Law states: “The electromotive force around a closed path is equal to the negative of the time rate of change of the magnetic flux enclosed by the path.”

 

So in simple terms, when the liquid moves faster, more voltage is generated. The voltage signal is detected by electrodes in the sensors and the velocity is calculated. By knowing the diameter and hence the area through which the liquid is passing and multiplying this area by the velocity detected, flow rate is calculated.

 

Benefits of electromagnetic flow meters

  • Minimal pressure drop – magmeters can be an ideal solution for wastewater applications that require a low maintenance solution without pressure drop as they can provide an unobstructed flow path when installed
  • Low maintenance – as there are no moving parts they can be very robust and a good solution for pipes which are difficult to access, however there should still be a regular schedule of maintenance where the internal pipe bore is cleaned and inspected
  • Highly accurate – typically between ±0.25% or 0.5% of rate (depending on model)
  • Space requirements – an electromagnetic flow meter requires a straight uninterrupted approach length of 10 x the diameter, although a minimum of 5 x diameter can be acceptable

 

Alternative solutions

Provided the conditions are right, a clamp-on ultrasonic flow meter can be a convenient and affordable alternative. This type of flow meter can be installed without cutting the pipe and therefore simplifying installation. Ideally, this type of flow measurement needs a greater upstream straight length of pipe than a magnetic flow system and can be less tolerant of detecting flows where there is entrained air or where solids are deposited on the internal pipe wall.

 

Read our guide to ultrasonic flow meters to learn more about this flow measurement technology.

 

Electromagnetic flow meter installation and maintenance

Electromagnetic flow meters are often labelled a “fit and forget” solution due to their high reliability in giving good long term accurate flow data with low maintenance requirements.

 

The lack of moving parts on this type of flow meter means it is a robust and easy-to-maintain solution that rarely breaks down, however we do still recommend occasional (but regular) servicing to ensure it is working to optimum standards.

 

The design of an installation should take into account access for maintenance such as cleaning/rodding or inspecting the inside of the pipe and sensor, for removal of the sensor and for the installation of a verification flow instrument.

 

Quite often flow systems, especially where MCERTS certification is required can be compromised by the installation design being poor and as such the design should be undertaken by someone with the necessary skills and knowledge. Unfortunately this often means the absolute minimum design conditions are suggested, and while this might initially seem cost effective, it usually results in a new flow measurement system having the worst acceptable conditions and being less tolerant of error or other system variations.

 

Talk to the experts

Our team of experts have can offer advice and guidance on the best type of flow meter for your requirements. We encourage you to get in touch to find out how we can help on hello@siris.co.uk.

 

Additional resources