• Twitter
  • Facebook
  • LinkedIn
  • Mail
  • Call Me Back
  • About
  • Knowledge
📞 Call us on 0330 223 31 31
Water Treatment Services
  • Home
  • Water
    • Applications
      • Boiler Water Treatment
      • Cooling Water Treatment
      • Closed Loop Water Treatment
      • Legionella Control
    • Services
      • Cooling Tower Cleaning
      • Cooling Tower Maintenance
      • Chlorine Dioxide Water Treatment
      • Commercial Water Softeners
      • Expert Witness Services
      • Pre-Commission Cleaning
      • Tank Reline & Repair
      • TMV Servicing
      • Water Chlorination & Disinfection
      • Water Leak Detection
      • Water Testing
        • Drinking Water Testing
        • Metals Testing
        • Pool Water Testing
        • BSRIA Closed System Testing
        • SDI Testing & Analysis
        • Trade Effluent Testing
    • Training
      • Water Treatment Training
      • Basic Chemistry of Water
      • Industrial Treatment
      • Pre-Treatment
      • Boiler Treatment
      • Cooling Systems
      • Closed Systems
      • Wastewater Training
      • Advanced Treatments
      • Training Dates 2021
  • Wastewater
    • Metals Testing
    • Trade Effluent Testing
    • Wastewater Training
    • Expert Witness Services
  • Air
    • Ductwork Cleaning
    • Indoor Air Quality
    • Local Exhaust Ventilation Testing
    • Mould Testing
    • Expert Witness Services
  • Energy
  • Legionella
    • Legionella Risk Assessment
    • Legionella Training Courses
      • Legionella Awareness Training
      • Responsible Person Training
      • Water Hygiene Awareness
      • Pseudomonas Training
      • Training Dates 2021
    • Legionella Testing
    • Expert Witness Services
  • Contact
  • Search
  • Menu Menu
You are here: Home1 / Knowledge2 / Energy3 / Closed System Filters – Equipment Selection Guide
Closed system filters - equipment selection guide

Closed System Filters – Equipment Selection Guide

This equipment selection guide reviews the use of closed system filters in closed heating and cooling water systems. The guide looks at the different types of filtration system available, why you should be using one, how they work, understanding temperature and pressure considerations, and the benefits this type of closed loop filtration can deliver.

Why use closed system filters?

When it comes to the treatment of engineered water systems, closed recirculating heating and cooling systems are often ignored, or at least not commissioned or managed to ensure optimum performance is achieved.

While such closed systems should still be treated chemically in an attempt to control both bacteria and corrosion, it’s also important to incorporate some form of in-line or side-stream filtration to help remove unwanted sludge, fine debris and suspended solids from the system.

  • Learn more about the treatment of closed systems

How can filtration of a closed system help?

Even though as the name suggests, closed systems are in theory sealed or closed to the atmosphere, that doesn’t mean that solid matter can’t build up through the effects of corrosion, alterations, leaks, poor commissioning or inadequate maintenance.

One of the main signals that solids have become a problem in a system is the presence of cloudy or discoloured water.

If you don’t do anything to address these problems, then a build-up of solids in the system could cause a number of potentially damaging (and costly) conditions including:

  • Corrosion

    System corrosion resulting in increased solids, sludge and premature failure of components.

  • Erosion

    Components become eroded by the the abrasive action of solids moving round the system leading to premature failure.

  • Bacteria

    Growth of bacteria and biofilm leading to poor water quality, increased sludge and reduced heat transfer efficiencies.

  • Deposits

    Formation of deposits reducing water quality, increased sludge and reduced heat transfer efficiencies.

  • Reduced Lifecycle

    Accelerated deterioration of parts of the system such as seals, valves, instruments or pipes.

  • Chemical Treatment

    Water treatment chemicals become less effective and leave the system vulnerable to biological growth and corrosion.

If you introduce an effective closed system filter system, you can help avoid many, if not all of these issues.

The primary aim of this type of filter is to remove any contaminants including suspended solids, from the closed system and so prevent the problems they cause.

The most commonly recommended closed system filter solution is a side-stream filter.

This type of system has the benefit that the flow of water through the main stream will remain unaffected if the filter itself becomes clogged or develops a flow problem.

  • Learn more about side-stream filtration
  • How BSRIA closed system water testing can help

Selecting a closed system filter

The type of filtration you select for a closed heating or cooling system will typically be determined by the type and size of the solids contaminating the water.

Some of the issues to be considered when selecting a closed system filter system include:

  • Capital cost of the closed system filter installation
  • The size of the particles to be removed
  • Operating temperature and pressure of the system – heating or cooling
  • Impact of solid build-up on the filter
  • Operational costs
  • Whether the system is manual or automatic
  • Reliability
  • Ease of operation

What are the different types of closed system filtration?

Here we look at the different types of closed system filtration:

Bag and cartridge filters for closed systems

Bag and cartridge filters are one of the most common ways of removing suspended solids from a closed system and they are the ideal choice for smaller heating and chilled water systems often found in commercial office buildings.

They tend to be manual systems and typically incorporate a pressure gauge to monitor the pressure differential between the inlet and outlet. As the pressure begins to rise it will alert users that the filter bag or cartridge needs to be changed or flushed.

This type of filter is available in a range of filtration sizes typically between 0.35 and 0.5 microns.

When you first start using bag and cartridge filters, you may find that you have to use a series of progressively finer filters as you begin to clean-up the system… for example, you might start with a larger 50 micron filter to remove the largest particles from the system.

As the water quality improves this larger filter can be replaced with a smaller gauge filter and so on, until you reach your desired filter size and the water quality target is achieved.

Although they are simple and easy to use, bag and cartridge filters aren’t always the most efficient option.

The filtration system depends on manual operation to be effective.

When the filter needs to be changed, the closed system may need to be shut down, drained and flushed out.

It can also be expensive to maintain this type of system. You should also think about chemical treatment costs and water lost during this changeover when looking at whether this type of closed system filter is suitable for your operation.

High performance closed system filters

High performance filters are designed to remove suspended solids as small as 5 microns.

They use a special high-surface media which allows particles to enter the filter bed but can still be easily backwashed.

This style of closed system filter is typically self-cleaning, and the backwashing process is automatic.

A high performance filter is efficient when taking particles out of closed systems operating at lower water temperatures, and with a maximum pressure of 100 psig.

High performance filters can often run for longer before they need back-washing, which saves on water consumption.

Most can also be set to backwash automatically, giving operators the control to select the pressure.

High performance filters also use fresh makeup water in the backwashing process.

If your system operates at higher temperatures or higher pressures, then you can also install a hot water filter.

These can operate at higher temperatures and pressures (typically to 250 psig).

A hot water filter of this type will have usually incorporate a three way motorised valve to allow flow rate monitoring and ports for taking water samples.

Super performance filters

As the name suggests a super performance filter can remove very fine solids from a closed system, as small as 0.5 microns.

This type of filter uses sand and other filters along the surface and is designed to operate at higher flow rates.

They are designed for closed systems operating at higher water temperatures and pressures up to 100 psig.

If you want to use a super performance filter in a closed system with particles larger than 5 microns, this will usually lead to a loss of water from the system and more frequent back-washes.

These filter systems also use fresh water during back-washing which helps to keep water lost from the system to a minimum.

Sand filtration for closed loops

One of the main benefits of sand filters is that they come in a wide range of sizes and designs.

The closed system water being treated passes through the sand filter and the suspended solids become trapped, with clean water emerging from the bottom.

If a sand filter is properly installed and managed, it can be used to remove fine particles as small as 5 microns.

Sand filters do require to be back-washed frequently to get rid of accumulated solids and this process is typically automated by either a timer or activated by using inlet-outlet pressure differentials.

When using inlet-outlet pressure differentials it’s usually a good idea to incorporate a back-up timer which will start the back-washing after a set period.

This stops hard or matted deposits from accumulating.

Additionally, if you backwash sand filters with makeup water instead of water from the closed system itself, this should keep your water and treatment chemical costs down too.

The case for closed system filters is clear

Using some form of filtration in a closed heating or cooling system is essential to ensure optimum performance is achieved.

The installation of this type of equipment can bring with it a number of benefits including:

  • Improved System Efficiencies

  • Reduced breakdowns & maintenance costs

  • Extend equipment lifecycles

  • Lower energy & water costs

Specialist engineering and industrial water management solutions

Water Treatment Services offer a comprehensive range of innovative engineering and water management solutions including the design and installation of closed system filter systems, and the management of closed heating and cooling installations to optimise performance.

Our experts can provide advice and support to help you identify the most appropriate strategies for the management of your heating and cooling water systems.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained water treatment engineers and equipment specialists we offer cost effective engineering and environmental support solutions across the whole of the UK and internationally.

Contact us today to learn how our industrial water management solutions can help you.

Contact Us Today

Further reading…

More information about our specialist closed system water treatment solutions

Tags: Closed Systems, Closed Systems Training, Side Stream Filtration, water treatment
You might also like
Biocides for closed systems Choosing Biocides for Closed Systems – Closed Circuit Heating & Cooling Systems
All about wastewater and sewage All About Wastewater Treatment
PD 855468:2015 - flushing and disinfection of water in buildings PD 855468:2015 – Flushing & Disinfection of Domestic Water Services
Role of the responsible person for legionella control Taking on the Role of the Responsible Person for Legionella Control
Iron and manganese removal from water supplies Iron & Manganese Removal from Water Supplies
Pre-commission cleaning of closed circuits Pre-Commission Cleaning of Closed Circuit Pipework Systems
Closed system water treatment guide Closed System Water Treatment Options for Heating & Cooling
Ion Exchange Water Softeners Ion Exchange Water Softeners

Search…

What’s New

  • PWTAG Code of Practice for Pool Water Treatment

    PWTAG Code of Practice for Pool Water Treatment

    In this pool guide the water management experts at …
  • In-Field Wastewater Testing for Plant Operators

    In-Field Wastewater Testing for Plant Operators

    In this article the industrial wastewater specialists at WTS …
  • Guide to Testing Swimming Pools and Hot Tubs

    Guide to Testing Swimming Pools and Hot Tubs

    In this pool guide the water management experts at …
  • How Boiler Water Treatment Affects Performance

    How Boiler Water Treatment Affects Performance

    In this article the industrial steam boiler specialists at …
  • Improving HVAC Energy Efficiency

    Improving HVAC Energy Efficiency

    This article examines how businesses can optimise energy consumption, …
  • What is Waste Acceptance Criteria or WAC Testing?

    What is Waste Acceptance Criteria or WAC Testing?

    In this article the industrial waste specialists at WTS …

REVIEWS

4.8
Rated 4.8 out of 5
Water Treatment Services is rated 4.8 out of 5 stars (based on 97 reviews)
Read our reviews

Free Newsletter

Receive exciting features, news, latest research and special offers! Just add your email address and we'll do the rest.

Contact us

Water Treatment Services

[email protected]

Tel: 0330 223 31 31

© Copyright 2022 - EDG Ltd. Operating as Water Treatment Services
  • Twitter
  • Facebook
  • LinkedIn
  • Mail
  • Home
  • About
  • Careers
  • Privacy
  • Environment
  • Reviews
  • Sitemap
Reducing Radon Gas in Homes and the WorkplaceRadon gasWhen to test for legionellaWhen Should You Test For Legionella?
Scroll to top

This site uses cookies. By continuing to browse the site, you are agreeing to our use of cookies.

OK

Cookie and Privacy Settings



How we use cookies

We may request cookies to be set on your device. We use cookies to let us know when you visit our websites, how you interact with us, to enrich your user experience, and to customize your relationship with our website.

Click on the different category headings to find out more. You can also change some of your preferences. Note that blocking some types of cookies may impact your experience on our websites and the services we are able to offer.

Essential Website Cookies

These cookies are strictly necessary to provide you with services available through our website and to use some of its features.

Because these cookies are strictly necessary to deliver the website, refusing them will have impact how our site functions. You always can block or delete cookies by changing your browser settings and force blocking all cookies on this website. But this will always prompt you to accept/refuse cookies when revisiting our site.

We fully respect if you want to refuse cookies but to avoid asking you again and again kindly allow us to store a cookie for that. You are free to opt out any time or opt in for other cookies to get a better experience. If you refuse cookies we will remove all set cookies in our domain.

We provide you with a list of stored cookies on your computer in our domain so you can check what we stored. Due to security reasons we are not able to show or modify cookies from other domains. You can check these in your browser security settings.

Google Analytics Cookies

These cookies collect information that is used either in aggregate form to help us understand how our website is being used or how effective our marketing campaigns are, or to help us customize our website and application for you in order to enhance your experience.

If you do not want that we track your visit to our site you can disable tracking in your browser here:

Other external services

We also use different external services like Google Webfonts, Google Maps, and external Video providers. Since these providers may collect personal data like your IP address we allow you to block them here. Please be aware that this might heavily reduce the functionality and appearance of our site. Changes will take effect once you reload the page.

Google Webfont Settings:

Google Map Settings:

Google reCaptcha Settings:

Vimeo and Youtube video embeds:

Other cookies

The following cookies are also needed - You can choose if you want to allow them:

Privacy Policy

You can read about our cookies and privacy settings in detail on our Privacy Policy Page.

Privacy
Accept settingsHide notification only