Steam filters have several uses, they include:

• Filtering and purifying Steam – the steam filters extract and trap the common contaminants usually found in steam sources.

These contaminants include dirt, scale particulates, and rust.

Once these particles get removed, then the steam gets released to the downstream filters, such as sterile filters, to begin the sterilization process.

• Reducing differential pressure when the steam flow rate is high. Consequently, the steam flows smoothly to the subsequent filters.

Yes, there are specific requirements for steam filtration requirements.

Initially, an effective filtration requires an almost complete removal (about 95%) of all particulate that are more than 2 micrometers in size.

If done this way, it would mean that you eliminate all the hazardous particles.

Secondly, the process has to include a filtration component from where all these trapped substances get suspended.

The filtration component would also protect every part of your system from getting contaminated.

Steam Filtration Process

• Removal of unwanted particles and contaminants – conventionally, most people consider steam as sterile and micro-organism free.

However, during the piping, steam may contain some contaminants, as earlier mentioned.

Besides, chemicals from boiler water additives and condensed water might be present.

You must eliminate all these contaminants before using the steam.

And that’s what Steam Filtration systems do.

• It increases the lifespan of the more fragile filters or downstream equipment.

Steam filters clean and remove the coarse particulates from steam, which, if left, may tamper with the other subsequent filters.

Therefore, it lengthens the life span of such downstream filters.

• An effective steam filtration system has got a high level/high efficiency rate of capturing unwanted particles of up to 10 microns.
• Cuts down operational expenses – the operational costs reduce by a reduction in the more costly and time-consuming cleaning.

Moreover, there would be a significant reduction in the maintenance costs of the sterilizer parts, including valves, and door seals.

• Steam filters eliminate the non-reactive boiler feed additive chemicals.
• The filters reduce the degree of wetting and staining of the sterilizer by-products. From the sterilizer, the filtrate emerges while dry and clean besides.
• They are safe for coming into contact with food.

Note that the Steam filter is always installed in the steam line just upstream of the sterilizer regulator valve.

Filtration Process

Now, the steam from the line enters the filtration system via the filter housing straight into an expansion chamber.

At this point, the incoming steam abruptly changes direction and flow velocity.

Consequently, a lot of the condensate gets expelled from the steam.

Afterward, the steam flows upwards still in the housing and passes through the microfiber filter tubing; then it flows downward, heading to the exit port.

The microfiber filter tube removes all the solid particles suspension and the condensate.

Usually, the filter tubes are more than 98% efficient for the expulsion of 0.1 micron and bigger particles.

Eventually, via the automatic condensate drain, the draining water from the filter tubes and the expansion chamber automatically drips.

Solid particles eliminated remain embedded deep in the filter tubes while liquid water.

On the other hand, drips intermittently from the filter tube into the automatic drain.

With that procedure, you obtain a clear and uncontaminated steam filtrate.

Yes, you could experience problems during steam filtration.

The problem might result from the build-up of contaminants on the filter elements, thereby hampering the efficiency of filtration.

The filtration process may also face differential pressure drop and contamination by rusts, carbon particles present in the piping.

Steam Filter Element

Except for clean steam, the conventional steam you generate from the boiler does contain large quantities of contaminants.

These contaminants do come from the piping and the boiler feed additives, which you need to filter finely.

Filtering the steam would thus help in ensuring:

• No damage to critical orifices.
• No contamination of products
• Increase in efficiency of the processes.
• It offers enough protection to the downline filters.

Some of the main common types of steam include

Steam Curve

i. Culinary Steam

Culinary steam refers to the kind of steam applied in the food processing industry.

Such sort of steam must comply with the 3A sanitary standard and 3A Accepted Practices for dairy and food processing.

Culinary steam when the need is may come into direct contact with the end product.

ii. Process Steam

Process steam is a general term used for referring to all the classification of steam for transfer of energy for applications, including heating, pressure control, or mechanical drive system.

iii. Saturated Steam

Saturated steam is a type of steam that would not take in more heat energy in a specified capacity unless pressure is capable of rising.

Saturated steam is suitable for thermostatic processes, including cleaning and sterilization.

iv. Dry Steam

Dry steam contains entirely 100% water vapor in the gaseous phase.

It is mostly useful in petrochemical and pharmaceutical applications.

v. Superheated Steam

Superheated steam is achievable by continually adding more heat energy leading to a continuous rise in temperature.

It applies to the production of electricity and other mechanical applications.

Steam filters are widely applied in several sectors/ areas including but not limited to:

• Chemical industry
• Aseptic packaging
• Dairy products industry
• Breweries
• Food and drinks industry
• Pharmaceutical industry
• Electrical/ electronics industry
• Fermentation industry

The essential components of the steam filter system consisting of a steam filter element and steam filter housing.

1. Steam Filter Element

The steam filter element forms the base of the extraction of particles from the filtered stream.

Therefore, due to the aggressive and harsh vapor it handles, it is highly durable.

Besides, the filter element has a bigger capacity for accommodating the trapped dirt.

Steam Filter Element

2. Steam Filter Housing

The housing is suitable for the substitutable filter elements, which are specific for distinct filtration grades of 1, 5, 25µm.

For turgidity purposes, the housing is stainless steel.

Still, the housing is customizable to suit the varied needs of different applications and to fit perfectly for installing the different filter element sizes.

For instance, the housing component of the food and Beverage applications must suit 3-A sanitary standards.

Regardless, the housing may adhere to the European directive standards of 97/23/EF.

Steam Filter Housing

You can specify team filters based on the following key criteria:

· Specify the Type of Filter Media

The kinds of filters applicable for steam filtration are can be grouped into three major categories, namely: sintered, pleated mesh, and pleated sintered.

Every type of filter performs a unique kind of filtration suitable for a specific application.

· Determine the Right Steam for your Application.

Importantly, you need to evaluate your application while considering the type of steam you aim at achieving.

With the right kind of vapor in comparison with your use, you can now settle down on the suitable steam filter element.

For instance, process steam requires 5 microns or 25 microns pleated and sintered filters, respectively.

Culinary steam for culinary grade steam filter, while clean steam is suitable, is achievable with a 5-micron filter.

· Consider the Material of the Filter Element

Stainless steel material is the absolute top-grade material for the element.

The end caps of the filters, porous filter media too should be stainless steel.

The type of steel makes the element durable.

Another conventional material for the filter element over the past is carbon.

Carbon though is suitable for temperatures of a maximum of 260 degrees Celcius and pressures of 27.5 bar.

Elsewhere, stainless steel withstands temperatures of up to 371 degrees Celsius and more pressure than the carbon type.

· Choose a Suitable Size of the Filter for your Application

You can choose a stainless steel element media from a wide range of formats such as 1, 2, 5, 10, 15, 25, 40, and 50 microns concerning your requirements.

For culinary system applications, the 5-micron element would be highly efficient.

· Check Conformity to Quality Standards

Just like other mechanical products, always verify if the steam filter element complies with the cGMP requirements.

Selecting a steam filter housing may be challenging yet very critical. Consider the following issues to assist you in deciding on the best type.

Steam Filter Housing

· Consider the Steam Filter Housing Material

Stainless steel material makes the housing strong enough to withstand high differential pressure of up to 250psi operating pressure or more.

Specifically, 304 SS is appropriate for process steam filtration applications.

If your use involves corrosive chemicals, then 316 L SS is advisable.

Culinary steam, food, and other sanitary applications require sanitary grade, 3 –A housing.

Therefore, the 304 SS suits several applications; however, 316 L is better since it is highly resistant to corrosion.

· Pick one with a Valid Warranty

You may opt for filter housings that come with a multi-year unlimited warranty for the sake of manufacturing defects.

· Choose one that Complies with Quality Standards

Ensure you verify if the steam filter housing complies with some of the significant quality standardizations.

· Identify a Suitable Size

The filter housings are available in at least ten varied sizes, and they have got several capacities, so you must ensure that you specify your preferred size.

· Number and Type of Connections

Filter housings come with different associations, others one, two, or even three.

The regular connections include (BSP, ASA or DIN, NPT, ANSI)

The steam filters fall into three major categories, namely: sintered, pleated mesh, and pleated sintered metal fiber.

· Sintered Filter Type

The sintered filter type gets manufactured from metal powder in conditions of extreme temperatures and pressures.

Sintered Filter Media

The filter types possess the following features:

• The tight pore structure
• has got a small surface area.
• Little rates of flow
• They are relatively less costly.

· Pleated Mesh

The pleated mesh is achievable by merging metal wires to produce a mesh.

Thus the pleated mesh has the following features.

Pleated Mesh Filter Media

• High surface area
• Elevated rates of flow
• Relatively costly
• They have got a lot of open structures.

· Pleated Sintered Metal Fibre

The pleated sintered metal fiber comes as a result of sintering all together both the high temperature and pressure little metal fibers.

This technique produces a material that is a metallic kind of glass microfiber element.

• These types of filters have the following characteristics:
  close-fitting pore structure
• Large surface area
• A high degree of flow
• Costs more than pleated mesh.

A micron rating is a unit that we use to show the capability of a steam filter to extract contaminants by the respective sizes of the particles.

However, filter specialists suggest that a micron rating alone cannot entirely describe the operation of a filter.

Thus associated beta ratio or the filter’s removal efficiency of the particular size particles must be considered.

Nevertheless, a filter of micron rating of “10 microns” is capable of capturing small particles of 10-micron size.

Above all, a micron rating is available in several variations.

The widely used micron ratings are nominal and absolute ratings:

Beta Ratio

Nominal Micron Rating

Nominal Micron Rating refers to the capability of a filter to extract particle contaminants of a specific dimension but at an efficiency ranging between 50% and 90%.

For example, when given a nominal rating of say 60% at 20 microns, it means that the filter can capture 60% of contaminants 20 microns in size.

However, you need to note that nominal micron ratings themselves have varied efficiency.

They may range between 50 – 98.6 % efficiency when extracting a specific particle dimension.

Absolute Micron Rating

Absolute Micron Rating refers to a filter that can remove a minimum of 98.7 % of a particular size particle.

To determine the rating, the manufacturers either use a single pass or multipass test.

It is a technique whereby fluid/ steam that contains measurable particles follows through a flat sheet of the filter media.

Afterward, they measure and count particles that go through.

Most manufacturers prefer this rating as opposed to the nominal micron rating because it is more detailed.

So next time, remember to ask your manufacturer if the micron rating presented to you is either a nominal or absolute rating.

Besides, seek to get the percentage of efficiency rating as well as the capacity of the contaminant.

This kind of information will enable you to assess the functioning of the filters.

Steam filter sizing refers to the distinct pore size of the filter element or media.

Therefore, you need to select a suitable filter size that efficiently removes the smallest microorganism/ contaminant you wish to extract.

When purchasing a steam filter, it is vital to do steam filter sizing.

However, you need to consider the following issues to pick the most suitable size for your application.

i. Establish the LargestPermissible Pore Size.

Try to select a suitable pore size, possibly.

A lesser pore size than necessary cut short the lifespan of the steam filter element while also generating a higher pressure drop.

Elsewhere, one with a bigger pore size than necessary effectively lowers the lifespan and efficiency of the downstream sterile filter.

ii. Operating Flow Rate

Determine the flow rate of the steam involved in your system in lb/h or km/h. the flow rate then subsequently determines the size of the filter.

iii. Vapour Pressure

each specific filter has a rating of maximum operational pressure.

Thus you need to have a precise measurement of the maximum pressure when sizing the steam filter.

The pressure is usually measured as bar or psi.

iv. Permissible Pressure Drop

The pressures are measured in psi or bar.

Manufacturers recommend the use of a pressure drop of at least 1.0 psi or 0.07 bar.

Remember, extreme pressure drop decreases the general lifespan of the steam filter element.

Nominal (NPS) and Absolute pipe size for the inlet and outlet of the already installed filter.

Also consider the mode of connection, for instance, NPT, plumbing, spigot, or flange.

Installing a steam filter system is quite easy and does not require several auxiliary appliances.

Most suppliers and manufacturers are shipped when completely assembled; it comes with a filter element already installed and ready to connect into your steam line.

Both the inlets and outlet ports are distinctly separated, for example,1-inch NPT for some filters.

The filter does not weigh a lot, and therefore your steam line can quickly and efficiently support the filter.

Besides, you do not require any additional mounting bracket for use during installation.

Again, install the filter on the upstream segment of the sterilizer steam control valve, and should be very close to lessen the condensation.

For precautionary measures, insulate the filter housing to the level of the external compression ring and the filter’s vapor piping downstream.

The insulation usually prevents the condensation between the filter and the sterilizer.

Replace any iron pipe downstream of the filter with a corrosive resistant pipe, usually stainless steel, to avoid further contamination.

Steam filters are replaceable when they become hugely defective and inefficient.

However, mostly, you would replace the filter media discs, and that’s all.

Manufacturers propose that the steam filters would last for approximately six years when properly used and maintained.

Condensate is the crucial cause of the blockage of the steam filter.

Large quantities of Condensate come from the steam mains, especially on fresh start-ups from cold.

Allowing large amounts of condensate to form in the distribution channels continually causes debris to come from the base of the pipe.

The waste then gets collected and transferred onto the filter chambers by the condensate.

That phenomenon results in the breakage of a culinary-grade steam filter very quickly.

So the ultimate solution is to eliminate the condensate; with that, you significantly reduce the chances of picking up contamination from the pipes.

Steam filter regeneration refers to the process of reconverting or re-establishing the original operational ability of the filter.

The significant reasons for regenerating the filter are to eliminate settled contaminants, lower pressure drops, and avoid a lasting contamination backlog.

Regeneration thus involves several techniques, although the common one is by cleaning.

Yes, it is advisable to clean your steam filters.

The more you frequently wash the filter element, the better it is regenerated.

You can effectively clean the stainless steel steam filter elements using a dilute solution of hydrochloric acid, water, air, or ultrasonic bath.

Also, you should clean your steam filter elements whenever the differential pressure clocks 1.0 bar (approximately 15 psi).

However, some filters, even after washing, would still maintain a pressure drop of about ten psi or 0.7 bar.

Such steam filter elements have fully exhausted their lifespan.

You can use the following techniques to clean the steam filters.

I. Counter Flow

With this method, you wash the filter media using either a clean liquid or clean gas in a reverse or counter-flow manner.

You can also pulse the flow to detach the sticking particles on the media, thereby enhancing cleaning.

Counterflow is efficient when extracted particles attach to the surface of the filter media rather than cleaning the particles penetrated inside the media pores.

You can use a nylon brush or wire to enhance the counter-flow method of cleaning.

II. Solvent Cleaning

Solvent cleaning or use of detergents is effective if oil or oily contaminants present in the steam make the particles retain inside or on the filter media.

The solvent/ detergents would then scrap away the oily pollutants as well as the trapped particles.

III. Ultrasonic Cleaning

Ultrasonic cleaning is the most thorough or effective technique of cleaning.

For this technique, you immerse the filter elements in a solvent or water bath.

Under the solvent trough or water bath is the ultrasonic vibrations that loosen or remove the particles that stick on the filter media.

Below are the standard guidelines you can use to select a steam filtration system.

• Select the filter system with a suitable material.

The material should be chemically well suited with the kind of steam you need to filter and which best fits your application.

Therefore choose between 304 SS, 316L SS, or carbon.

• Establish if you will require a single-stage or multi-stage filtration system. If you need a multi-stage filter system, then choose the final filter first.

Again, multi-stage filtration is essential with plugging streams.

• Before selecting the final filter, determine the smallest size of particle you would wish to retain. When done, now select the proper pore size.
• Choose the prefilter compartment that you may install before the final filter to provide the best blend of retention and capacity.
• If so, choose the final prefilter, which has retention that is close to the one in the last filter.
• Assess if the differential pressure is compatible with the filter and the filtration procedure. Note that the eventual differential pressure across the cartridge, ie. the change out pressure drop is a definition of the particle and filter interaction.

Carbon steam filters are a traditional filter media tracking back to the 1950s.

Carbon is suitable in temperatures of up to 260 °C and pressure of 27.5 bar per squared inch gauge.

But since carbon has a sandpaper-like texture, most granulated carbon tubings shed particles during usage.

On the contrary, stainless steel can withstand a high temperature of up to 371 °C and much more pressure.

Besides, you can ultrasonically clean the stainless steel filters a maximum of six times before you replace them.

The above distinct differences make stainless steel the better option in the three applications.

Carbon Micron Filter

Stainless Steel Steam Filter

To comply with Dairy Needs – The stainless steel Filter elements comply with the regulations of the Pasteurized Milk Ordinance (PMO).

Production of culinary–grade steam – the stainless steel filter media conforms to the 3-A standards.

First, The steel media does not shed fiber.

Two, stainless steel filters have no binders, additives, adhesives, or any other surface reactive agents that might leach during the filtration.

It withstands water hammer – stainless steel is highly resistant to chipping, shattering, or cracking.

I hope you have learned a lot about steam filters.

Most likely, you could be having more specific or personalized questions regarding steam filtration systems.

You can contact Filson Filters experts now for free consultations.