Key points
When it comes to the efficient transfer of heat, steam is difficult to beat thanks to its ability to hold a great deal of energy, while remaining clean, reliable and sterile. In fact, it is considered by many to be the ideal sterile and contaminate-free energy source, with its flexibility meaning it can be used to cook, sterilise, humidify, dry and heat.
Steam filtration is increasingly becoming an essential part of any processing plant environment in today’s innovation-driven world. From system cleaning to product processing, steam is a wide, varied, and valued part of the whole system. As a result, the demand for steam filtration continues to rise, especially in critical environments.
Steam is sterile in the sense that it contains no viable microorganisms. However, typical steam is not ‘pure’.
With companies expected to conform to the most stringent standards of hygiene and contamination control, it is critical that the quality of the steam they use – and the performance of the steam filters installed within the steam production system –consistently produces contaminate-free products.
Avoid product contamination through steam filtration
Filtration of steam is essential to avoiding product contamination and unnecessary equipment downtime – and it actually serves to increase system efficiency and protects sterile equipment, removing pipe-scale to prevent fouling of valves or injectors and inhibiting contamination of product.
There are several terms used for steam – from ‘culinary steam’ used in food processing, to ‘process steam’ used in process applications as a source of energy for process heating, pressure control and mechanical drives. Process steam does not generally come in contact with the final product whereas culinary steam can, and often does.
The difference between culinary steam and process steam
Culinary steam filters are an essential part of any processing facility. In fact, your steam is only as good as your filter, with effective culinary steam filters helping to protect equipment from costly damage, removing debris and scale from steam lines and systems.
Culinary steam is defined by 3A Standard 609-01 as “steam that is free of entrained contaminants, relatively free of water in liquid form and is suitable for use in direct contact with milk or milk products or product contact surfaces.”
In practice this means that the steam filter should be capable of removing 95% of particles 2 microns in size and be manufactured from 300 series stainless steel or higher.
By using an effective filter, steam will be free from the contaminants that spoil the final product’s appearance, smell, or taste; lowering downtime and increasing processing efficiency.
Examples of using clean steam in product processing
A typical example of the use of clean steam in product processing is its injection into a vessel to create a sterile environment, whereby components such as ampoules can be processed.
In the pharmaceutical and healthcare industries, sterilization is one of the principle uses for steam. This can be for certain products, but more usually for the sterilization of critical equipment.
One such application is in the fermentation process which requires a high cleanliness standard of both air for the sparging operation and steam to aid in the sterilization of the vessel and associated pipework. Steam filters in this duty typically require a rating of 1 micron.
Process steam filtration is steaming ahead…
Process steam is used in a variety of applications within general process industries; clean, dry steam is critical for plant performance and continuous operation, but where there is no direct contact with the manufactured product.
Together with other manufactures Porvair offer a wide range of high quality, industry standard sterilization and processing filters as it looks to meet ever-growing industry demand for higher, more cost-effective performance across applications such as sterile packaging, pharmaceuticals, brewing, dairy farming, food and beverage, and chemical production.
For example Porvair’s Sinterflo® stainless steel filter elements are available in high quality 316L sintered metal fibre, metal mesh and sintered metal powder media; all cartridges have a fully welded construction ensuring an excellent resistance to high temperature environments.
Manufactured from randomly laid metal fibres, sinterbonded to form a uniform high porosity filter medium, Sinterflo® F in particular demonstrates a significantly low pressure drop, high permeability and excellent dirt-holding capacity. Pleated sintered metal fibre increases the available filtration area of a filter element, thereby further increasing dirt holding capacity and so minimizing maintenance and maximizing on-stream processing.
Cartridge integrity allows for a typical operation in steam from -51°C (-60°F) to 204°C (400°F), seal dependant, and up to 5bar (72psi) differential pressure in normal flow direction.
With the feasibility to formulate metal fibres to meet specific application requirements combined with inherent durability, sintered metal fibre filters can be cleaned in situ without interrupting process flow, thereby providing the ultimate in process economics.
Steam filters may be regenerated to extend the life and efficiency of the elements. To be specific, filter cleaning using the reverse flow technique may be very effective in fluid streams containing very low contaminants. However, care should be taken not to exceed the reverse pressure in this operation.
Other cleaning techniques may be employed for filters that are heavily contaminated or contain aggressive impurities. Ultrasonic cleaning involves the immersion of the filter elements in a non-flammable solvent or water bath. Ultrasonic waves are then used to remove particles embedded within the filter media. Elements which are ultrasonically cleaned may be returned to a near original condition.
Continuous innovation in steam filtration products enables manufacturers such as ours,to offer new and better solutions to applications – and the widened range for production processes is pivotal to that ‘strategy. It’s all in the pursuit of the best possible solutions for customers.
Honoured in 2015 in the UK with the Queen’s Award for Enterprise in International Trade, Porvair has supplied the process industry with performance-driven filtration equipment for over four decades.
