Making sense of ESPs

What do ESPs do?

ESPs (Electrostatic Precipitators) are designed to remove fine particles from air. These can be dust or smoke, or wet particulates such as grease and oil found in kitchen ventilation applications. Gaseous odour molecules known as VOCs (Volatile Organic Compounds) pass straight through ESPs and need to be treated by other means such as ozone injection, in-line UV-C or activated carbon.   

How do ESPs work?

ESPs work by ionising particulate matter and trapping these charged particles onto collector plates.  A number of factors contribute to their efficiency:

  1. The high voltage of the ioniser and collector cells.  This should be upwards of 12kV and 6kV respectively for maximum efficiency;
  2. Depth of collector cells – the deeper the better to ensure that the charged particles are trapped efficiently;
  3. Smooth air flow through the ESP.  It is important that there is laminar air flow through the unit. This allows for air to be equally distributed through the ESP. If the air flow is turbulent, for example if the unit is placed too close to a bend, or if there is no diffuser plate in the equipment, this will dramatically reduce efficiency.

In a Plasma Clean ESP, after passing through a diffuser plate and pre-filter, contaminated air passes across robust stainless-steel spiked ioniser blades. The charged particles then pass into a collector cell made up of a series of equally spaced parallel plates, and are then collected.

Figure 1. ESPs ionise airborne particles which are then captured on the parallel p[lates of a collector cell

Understanding the particulate collection efficiency of ESPs

This is an area where there can be a lot of confusion.  Particulate collection efficiency depends on the flow rate and particle size.  Generally speaking, efficiency at low flow rates and large particles is high. This reduces as the flow rate increases and the particle size decreases.

This is why it is important to check the stated flow rate and particulate size against manufacturers claims of efficiency.  If there is a stated efficiency of, say 99.9%, always check what flow rate and particle size this was tested at.

It is extremely important to keep within flow rate capabilities to maintain efficiency and performance. Always remember multiple units can be joined together for increased volume flow rate or efficiency.

Figure 2. Particle collection efficiency and static pressure data for single collector cell

What other factors are important when choosing an ESP?

Pressure drop and grease handling are other important factors to consider when choosing an ESP.

Plasma Clean ESPs have a pressure drop of 90Pa per pass even when dirty. This means that a smaller, lower power fan could be an option at the design phase and will certainly result in lower running costs. 

Grease handling is key. The grease which is collected by the ESP must be kept in check otherwise it is a fire risk.  Wherever possible there should be provision to drain the grease and oil. Where this is not possible, routine cleaning is required. A large grease collection tray presents a fire risk and should be avoided.

Figure 3. ESP with UV solution for total grease, smoke and odour control

Maintenance is important:

The grease and smoke collected by the ESP would otherwise find its way into the downstream duct work causing a fire risk and requiring TR19 Grease duct cleaning. By employing an ESP early on in the extraction system, downstream duct cleaning is dramatically reduced. This is particularly important when the duct runs through a building and access is not possible.

The ioniser and collector cells require a cleaning regime which normally involves exchanging the spent cells with clean ones. The ioniser and collector cell voltages should also be checked to ensure the equipment is working at its highest efficiency – if not, ask why.

On average for kitchen ventilation applications, this takes place every 3 months depending on the level of grease and smoke in the cooking process.

Click here to access a product datasheet on Plasma Clean ESPs.  

Product Specification:

In Summary:

Contact us for further information and a FREE consultation:

Tel: +44 (0)161 870 2325


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6 steps to fresh air

Looking for fresh smelling air and a DEFRA compliant kitchen?

Whether you’re involved in specifying commercial kitchens, installing kitchen equipment, or running a busy restaurant, air quality is a key concern.

As part of our service, our guide helps you exactly with this.

Step one: Site assessment

This first step is all about understanding the mechanics of the kitchen and its operation. To do this, we gather together information on a number of critical factors We also look at the likely sensitivity of the neighbourhood to odour problems, and establish the scale of the operation: How many hours is the kitchen open at a time? How many covers does it typically serve?

Step two: Defining cooking activity

We next look at the type of cooking. Different types of cooking produce different levels of grease, smoke and odour. A fish and chip shop, for example, produces high levels of grease, very high levels of odour, and low levels of smoke. A Gastro-pub cooking steaks on a chargrill, on the other hand, produces high levels of grease, smoke and odour. To be effective, systems have to take these differences into account.

Step three: Choosing the right solution

Assessment complete, we select the combination of solutions from our range that will best keep the kitchen and neighbouring areas grease, smoke and odour free.

Step four: Specifying the solution

Using volume flow rates, we calculate the correct configuration of solutions required for best results and confirm where they should go. Our range is modular, meaning we can plug things together to give different options and strengths. At this point, we can also produce a grease, smoke and odour control strategy to show EHOs and Planning Officers you have an effective plan in place.

Step five: Installation

All products are designed to be easy to install and use. If we are kitting out a brand new kitchen, then installation is quick and straightforward. Ou solutions can also be easily retro-fitted.

Step six: Maintenance

Maintenance requirements vary from solution to solution but are all simple and straightforward. In fact, our carefully-designed and robust products typically need fewer routine service visits than competitor ranges. We’ll put together a schedule for you, advise staff what to do, and explain what you’ll need us to do.

Contact us and we will send you the 6 steps guide today.

For more information please click here.

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Winning the Food Hygiene game

Would you eat at a restaurant or from a takeaway with a Food Hygiene Rating of three or fewer?

What does the rating imply to you? Dirty kitchens? Maybe the odd cockroach hanging around? It’s not an appealing thought, is it?

Truth is, if you work in the catering game, you know you must display your rating by law.

The NFU Mutual Food Hygiene Rating Report found that 44% of people would turn away from a food establishment that displayed a rating of three or fewer and a huge 38% of people said that, if a favourite food outlet scored three or fewer, they’d stop visiting altogether.

Part of keeping your food-hygiene score high is keeping your kitchen clean. But we all know how hard that can be.

The grease problem

The problem is grease. It gets into the duct and coats it. Duct cleaning can also cost you £1500. And if it catches fire, your whole ventilation duct can go up. That will stop you trading in a heartbeat.

Complying with regs is also tough. And you need a yearly TR19 inspection, or your insurance is invalid. You also need a high Food Hygiene Rating if you want people to eat and recommend your food.

Here at Plasma Clean, we’re ventilation experts in the commercial kitchen market. We’ve been asked a lot of questions about the Food Hygiene Rating Scheme over the years and how we can help.

What is the Food Hygiene Rating Scheme?

The Food Hygiene Rating Scheme is run by your local authority together with the Food Standards Agency (FSA). It’s like an MoT for your food outlet.

The scheme gives consumers a snapshot idea about hygiene standards on your premises when they were inspected by food-safety officers. Their inspections check you’re complying with legal requirements and a rating from one to five reflects the findings.

The idea is to give the public the chance to make informed choices about where they eat out. This should encourage businesses to improve their hygiene standards.

As part of the scheme, the FSA has announced that the ratings must be displayed in your outlet. This should mean fewer ‘poorly compliant’ businesses.

Improving your hygiene standards should mean less food-borne illness. But does it apply to you?

Well, yes, if you supply food directly to customers. This includes restaurants, cafes, takeaways, food retailers, and any other place where people eat food prepared outside of the home.

What are Environmental Health Officers looking for?

The good news is that your business should be able to achieve the top rating. You just need to know what EHOs (Environmental Health Officers) are looking for.

EHOs give food premises a rating based on the physical condition of the premises and facilities as part of the criteria.

Food Hygiene Ratings assess:

  • Hygienic food handling
  • How food is stored
  • How food is prepared
  • Cleanliness of facilities
  • How food safety is managed

They’ll also check compliance with structural requirements, cleanliness and the condition of your facilities and building (including the layout, ventilation, handwashing facilities and pest control) to enable good food hygiene. It’s your responsibility to comply with food-hygiene law at all times.

Things to consider:

Want a 5-star Food Hygiene rating?

We can help you secure that vital five-star rating.

Here at Plasma Clean, our unique air-filtration and purification systems can reduce grease, help with Food Hygiene Ratings, and save you thousands on duct cleaning and kitchen shutdowns.

We specialise in the design, manufacture and supply of high-quality commercial kitchen ventilation grease, smoke and odour control.

We also provide consultancy services across a wide range of clean-air and surface-disinfection applications. This goes beyond our own product range, giving you a knowledgeable source of advice no matter what your particular environment and problem.

Just answer 5 simple questions

To find out exactly what kind of help you need in your kitchen, simply answer these five easy questions. This will help us offer you the best solution for cleaner facility and boost your chances of a higher Food Hygiene Rating.

We’ll get back to you with a professional response within 24 hours.

Any more questions about how we can help with Food Hygiene?

Chat to us today about how we can control grease, eliminate odours and save you serious money on duct cleaning. Call us on (0)161 870 2325 or email us:

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Want the WC and waste storage air smelling fresh and hygienically clean?

What is odour control? How does it work? And what are the trusted solutions?

The simplest way to describe this is if you think about nature.

During a thunderstorm you have high voltage which is created in a cloud. This high voltage needs to get to ground. It builds and builds and eventually the air starts to break down. When the air breaks down a plasma is formed. That plasma is lightning (!) which ionises the air. This is why the air smells so fresh after a thunderstorm.

The best solutions for odour control actually create this natural process. Our Ambion solutions are designed to ionise the air. In washrooms, waste storage areas – any space where there is odour which needs to be controlled.

Ambion in washroom

We have 3 different styles:

  1. Ambion 15 – can handle up to 15m2
  2. Ambion 25 – can handle up to 25m2
  3. Ambion 100 – can handle up to 100m2

Dr David Glover, Plasma Clean’s Founder & Managing Director:

“The reaction from customers who switch to these odour control systems from perfumed systems is initially a significant saving because you don’t have to buy the perfume sprays every month. The ionisers actually destroy that smell and it leaves the air smelling fresh and hygienically clean”.

Link to video.

Colour options available

Contact us today if you have any questions or if you are interested in any of our solutions:

T (0)161 870 2325



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Everybody needs good neighbours

Meet Phil and Jo. They’ve just moved into a buzzing, cosmopolitan neighbourhood. They’re young, they love a bit of city life and they’ve got everything on their doorstep – bars, restaurants, nightclubs, markets. They’re in heaven.

Even better, Phil and Jo love a late-night Chinese and, as luck would have it, there’s a takeaway right on their doorstep. Bring on the Dim Sum and chicken with chestnuts.

But they’ve not been there long before a few dark clouds drift across the horizon. Not so much dark clouds as pungent smells, and the drifting is all through their open window. Before long, Phil and Jo are keeping their windows closed and not venturing out.

Imagine you’re the owner of the takeaway. Phil and Jo complain to you. They’re good customers and you don’t want to upset them. You google ‘odour control for commercial kitchens’.

What’s happening is that a build-up of grease has coated your ductwork. The result is not only unpleasant on the nose, but it’s also a fire risk.

As an owner of a small commercial kitchen, this could be the death knell for your business. In extreme circumstances, especially when environmental health are involved, you might have to close down. But with the right technology in place, and the trusted solution, you can fix this situation and even get away with fewer duct cleans each year.

However, in smaller commercial kitchens, space, flow rate and budget are limited. For these kitchens, there’s only one UK manufacturer that can offer the right technology and expertise.

That’s us. At Plasma Clean, we’ve developed the ESP Lite and Techniclean Mini as a solution for smaller commercial kitchens.

These compact and cost-neutral solutions have the highest efficiency and the lowest pressure drop on the market. They also have the smallest footprint, so they’re easier to install.

The Techniclean Mini can fit into existing ductwork. Placed close to the kitchen canopy, it combats odours. It also reduces grease build-up in the downstream ductwork.

Use it on its own or in combination with the ESP Lite to control grease, smoke and gaseous odours. It’s a quick and easy fit inside the ductwork and it comes with an interlockong control panel.

Let us install it, apologise to Phil and Jo with a free Szechwan Chilli Chicken and all is good again.

Order the only bespoke grease, smoke and odour control trusted solutions for smaller commercial kitchens. Talk to Plasma Clean today on (0)161 870 2325 or email us at

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Some of our Clients