Why Use Stainless Steel For The Burner?
The cheap option, and one used on most generic heaters, is tin or chrome. Why? Simply put the moulding costs and raw materials are significantly lower than stainless steel. By using tin or chrome the metal is polished to look like stainless steel but given a few months in our maritime climate and the rust spots soon appear on the burner.
The big advantage to using stainless steel is servicing and maintenance. Rusty burners cannot be serviced and are disposable. Try getting a rusty bolt or loosen a screw on generic burners and you'll soon find why stainless steel is the only viable option in the manufacture of quality patio heaters.
Virtually all 16kw patio heaters in the UK still fit tin or chrome burners - even on stainless steel patio heaters they fit a tin or chrome burner. They have yet to catch up with newer technology and invest in the improved manufacturing process. It's worth remembering we are Europe's largest supplier of patio heater spare parts and since tin and chrome burners are non serviceable we no longer support spares for older 16kw patio heaetr models, these are now discontinued.
What is stainless steel used in the manufacture?
Stainless steel contain chromium, or a combination of chromium/nickel, as well as amounts of other alloy additions such as molybdenum. Chromium content of a stainless steel in patio heaters is generally greater than 15 per cent, it is this alloy that keeps the patio heater bright and rust resistant in spite of moisture or the action of corrosive acids and gases. Presence of nickel further improves the corrosion resistance as does molybdenum.
What are the types of grades?
The main requirement for use of stainless steel in patio heaters is that it should be corrosion resistant for the specified application and the environment it will be used in. The selection of a particular "type" and "grade" of stainless steel used must initially meet the corrosion resistance requirements. It is important to bear in mind that various grades of stainless steel will be used, some will be suitable in hotter climates whilst others would suffer from rust in a damp climate. A stainless steel heater produced for the South African market would not be suitable in the UK.
Why is a stainless steel patio heater "stainless"?
The corrosion resistance of stainless steel in patio heaters arises from a "passive", chromium-rich, oxide film that forms naturally on the surface of the steel. Although extremely thin at 1-5 nanometers (i.e. 1-5 x 10-9 metres) thick, this protective film is strongly adherent, and chemically stable (i.e. passive) under conditions which provide sufficient oxygen to the surface of stainless steel. Key to a stainless steel patio heater's durability of the corrosion resistance is that should the film become damaged it will self repair, provided sufficient oxygen is available. By contrast to other steels used in the production of budget heaters suffer corrosion where areas of the surface are affected, stainless steel used in BFX patio heaters are in the passive state and resistant to this form of attack.
Corrosion and oxidation resistance of stainless steel patio heaters
The corrosion and oxidation resistance within stainless steel heaters will improve as the chromium content increases. Additions of nickel to create the austenitic stainless steel grades will strengthen the oxide film to raise performance of stainless steel in certain conditions. Addition of molybdenum to either the ferritic or austenitic stainless steel patio heaters improves pitting corrosion resistance.
What to look for on patio heaters
The engine of all patio heater's is the burner, if the material is not listed expect a chrome burner fitted, if it's listed as steel expect a tin plated finish. These will last about two years on depending where it is situated, if in a coastal area the life expectancy of tin or chrome is about one year. Check terms, some web sites exclude warranty near coastal areas, this is of course illegal and a sure sign of a cheap patio heater manufactured in tin or chrome. Flame screens are always stainless steel but this is only a small part of the burner, the whole burner casing must be stainless steel to survive longer than a couple of years outdoors in the UK. All BFX models are fitted with a full stainless steel burners as standard - our 2012/13 burners feature the latest quick start high energy burners for maximum heat at low running cost. The latest commercial burners are fitted with a heavy duty double skinned stainless steel burner that provides ample heat at much lower running costs.
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