This article UTLÅTANDE ÖFVER FOTOGENKÖKEN PYRO OCH SVEA by Professor Abraham Langlet was kindly translated by Christer Carlsson. The original is in old Swedish and that is reflected in the translation. C.R Nyberg (SVEA) was obviously put out by some advertising claims of short-lived rival Pyro regarding the merits of their stoves and commissioned the professor to document his opinion of comparisons between the 2 brands of stove. I warn you now, that this is a dry and academic article and may not give you the most entertaining read you have ever had. However there are collectors like myself who find this sort of material fascinating - my apologies if you are not among them! To download a copy of the original Swedish document in PDF format (581kb) click here. OPINION Concerning the paraffin stoves Pyro and Svea By the Professor at Chalmers University of Technology in Gothenburg, Abraham Langlet Linkoln Bloms Publishing Ltd, Stockholm 1912 I have been requested by the manufacturer C.R. Nyberg to give my opinion regarding the advertising for the paraffin stove “Pyro” that has been seen partly in sales brochures, and partly in commercial advertisements. As material for my judgement I have been provided with examination reports from the institute for research of materials at the University of Technology and the Chemical-Technical bureau in Stockholm and with a paraffin stove of the brand “Svea”, in addition to which I have purchased a stove of the brand “Pyro”. After a careful examination of these documents, and after getting acquainted with these two stoves and their characteristics, I may now present the results of my investigation. The merits that would distinguish the paraffin stove “Pyro” in comparison to other constructions is, according to an in June 1910 published catalogue, mainly this: It’s the most excellent paraffin stove in the world. It’s more convenient to handle as a result of the fact that it light automatically without any pumping. It burns with an adequate, just right flame without any pumping. It’s much more efficient than any other stove, since it during the same period of time consumes only half as much paraffin, and make use of appr 20% more of the energy of the fuel. With the aid of pumping it’s able to boil one litre of water at only two thirds of the time any other stove would need. It’s constructed in a way that when extinguishing the stove, every gases and fumes incinerates which prevents any smoke, odour or soot completely. It can’t explode. It’s provided with an extremely strong grate out of tin, which is constructed in such a way that it generally prevents extinguishing the flame in the event of a boil over At page 8 in the same catalogue is pointed out in a specially framed note that; “Pyro (without pumping) in 3 hrs. of daily use saves more then half a barrel of paraffin (120 litres) compared to other stoves. In here enclosed advertisements are further claimed that “Pyro” is: The most excellent, most fuel saving and only vaporizing stove that lit itself automatically and burns without any pumping. Simple and easy to tend (the simplest and most easy to care). Smoke- and odour free. Explosion free Furthermore is the statement repeated which claims that Pyro at an estimated usage of three hours per day saves half a barrel of paraffin. Since the information in the advertisements also mainly is to be found in the catalogue, it should be enough to use the latter for this review, statement by statement. Concerning the first statement that Pyro is the most excellent paraffin stove in the world, you must say that this is a completely subjective opinion, and you have no reason to doubt that the manufacturer of Pyro has this apprehension. However, it’s doubtful whether any impartial person would agree to this superlative judgement. One thing is for sure, and that is that it’s impossible to control this in any objective way, and I don’t see any reason to do so since this claim in any practical means are pretty innocent. The hardened buyer has surely learned to take assertions like this from any manufacturer for what it is. That Pyro to some extents are more convenient to handle due to the fact that it light itself without any pumping are undoubtedly true. The benefit of this is however lessened by some of the disadvantages that follow with using self-pressurizing. The consumption of spirit can’t be brought down to the same low level as for e.g. the Svea (according to tests performed by both the institute for research of materials and the Chemical-Technical bureau, the least amount of spirit for lightening of the Pyro without pumping is 4cc compared to 2cc for the Svea). Furthermore it´s necessary to drain the Pyro after each tenth filling since water is accumulating in the tank. If this is neglected, the stove will extinguish itself. Due to the fact that the temperature eventually rises in the tank, the pressure will do so aswell, which may cause an unnessecary fuel consumption in the cases when full effect aren´t needed. How these disadvantages compensates the benefits are hard to tell without long experience. One thing is clear, and that is that this “automatic” lightning doesn´t only mean advantages. The third claim:”Pyro burns with an adequate and just right flame without any pumping”, however, are clearly false and contradicts itself by the fact that the manufacturer also provides the Pyro with a pump. According to the investigation made by the Chemical-technical bureau, it took more than half an hour to boil 1,5 litres of water on a Pyro stove using only self-pressurizing. Of course an in most cases all to long time. And if it’s about boiling larger quantities, e.g. 3-4 litres which in any household aren’t unusual, the losses of heat through the increased surface makes it impossible to reach boiling temperature without any pumping. The flame from an unpumped Pyro stove is only adequate if it shall keep an already boiling liquid still boiling or keep it at a high temperature, but are to large for this purpose if the quantity are lesser then half a litre. Therefore it must be an exception for the Pyro to always burn with an adequate flame without the aid of pumping. I want to point out in this matter that as far as I can find out from my tests with a Pyro provided with a pump, such a stove without a pump is awkward enough to most certinaly be the worst of all stoves I know, including the ones that uses a wick. Regardless of the inconvenience of the long time to reach boiling temperature, it also relates as such that if you have boiled a small quantity and then want it to simmer by decreasing the flame, you have to put the stove entirely out and let it cool off fully before you light it again in order to be able to get a flame of full capacity. That “Pyro with the aid of pumping is able to boil one litre of water at only two thirds of the time any other stove would need” is most certainly untrue, even though this statement are supposed to be based on “official, comparing tests of Pyro and other Swedish paraffin stoves”. First of all can´t this obviously not be the case compared to an extra large stove such as the Svea no: 2 which has almost twice the fuel consumption as the stoves with the same size as Pyro. Furthermore, the provided tests from the institute for research of materials at the University of Technology shows that the Pyro stove at the pressure of two atmospheres took exactly the same time to boil one litre of water as one of the stoves from Svea, and only insignificantly shorter time then other examined stoves from Svea and Primus. The opinion from the Chemical-Technical bureau makes clear that one of their stoves from Pyro took over a minute longer to boil then one of their stoves from Svea at the pressure of 1, 2 or 3 atmospheres. That the Chemical Bureau of analyzis, out of tests of Svea and Pyro made by the institute for research of materials at the University of Technology, has been able to calculate that Pyro at three atmospheres of pressure boils a litre of water out of appr. ¾ of the time it takes for a Svea (not two thirds as claimed in the catalogue), only shows that the stoves from Pyro are pretty uneven in their performance, which also comes clear from the tests made by the Chemical-Technical bureau. Pyro are also claimed to be “constructed in a way that when extinguishing the stove, every gases and fumes incinerates which prevents any smoke, odour or soot completely.” This statement is in it’s former part undoubtedly true if by gases and fumes are meant flammable such. But this does not mean any particular advantage for Pyro. What comes out of the air valve when extinguishing a stove is mainly air, which admittedly are saturated with paraffin vapour at the same temperature, but since this isn’t very high, the vapour amount are so small that it doesn’t cause any fumes. The advantage of this construction is so problematic that the manufacturer in his catalogue requests the user to let the air out via the pump or the fuel cap instead of through the air valve. This to avoid some inconveniences caused by the position of the valve! The more false is the statement in its latter part. The smoke, odour or soot from any paraffin stove has nothing to do with the position of the air valve, and if the usual stoves are handled correctly, this inconvenience will occur as little by them as by the Pyro. It is true that Pyro has one less reason for this inconvenience then others, and that is the lack of possibility to neglect the correct time to start pumping when lightening the stove. That reason has however nothing to do with the positioning of the air valve, and over all is this statement that the smoking etc. is totally prohibited, false. Just as little truth must lie in the statement that “Pyro can´t explode”. There is nothing in the construction of Pyro that justifies such a claim, and the problem to construct an explosion free stove is still to be solved, jet if the risk for explosions are very small. I have not been able to test the statement whether the grate of Pyro is constructed in such a way that it “generally prevents extinguishing of the flame in the event of a boil over”. The statement that Pyro without being pumped, at a three hours of use per day should save more then half a barrel of paraffin (120 litres) a year compared to other stoves are not only false, you can´t really get over the thought that it´s put in order to mislead. The same goes for the fourth statement; that it during the same period of time consumes only half as much paraffin, and make use of appr 20% more of the energy from the fuel then other stoves. The “official certificate” on which this statement bases itself upon, according to one of the advertisements from a newspaper, seems to be the one given by the chemist Paijkull saying that the Pyro when self pressurized only consumes 42,3% as much fuel as a Svea No: 11 does at a pressure of 1 atmosphere. As it is, it must be pretty easy for the manufacturer to deceive the public to believe that the Pyro saves 57.7% of paraffin compared to the Svea, which at a three hours of daily use maybe would reach the claimed half of a barrel a year. However, as far as I’m concerned, it’s totally unthinkable that a professional – and such a man must at least be behind the statements in the catalogue, and perhaps even in the advertisements – would claim such a thing in good faith. There is no information about how big the value of this “self pressure” should be, but considering the amount of fuel consumed it could hardly be more then 0,1 atmospheres. And the consumption of paraffin at this pressure is compared to the consumption of a Svea at ten times that! The public in general surely don’t reflects over the fact that Svea and other stoves of this kind don’t has to burn at higher pressure then Pyro – at which the fuel consumption and efficiency would be about the same – but the writer of the catalogue has no excuse for his ignorance in this matter; it must without exception be familiar for him that other stoves, as well as the Pyro, can be adjusted to a lower pressure then Pyro has when using self pressurizing, and as such gain a lesser consumption then the one stated for a Pyro at the same pressure. It seems unlikely to me that this false statement was put in good faith, and it is so misleading that you can’t but be sorry for the buying public to be exposed for such. It´s clear by the review above that the in catalogue and advertisements claimed advantages of the paraffin stove “Pyro” compared to other stoves are highly exaggerated, and in many cases all false, where at least one of them – the by its content and typographic outfit most striking – seems to have been put forward in the clear intention to mislead the general public. Gothenburg January 23, 1912. Abraham Langlet. The above by prof. Langlet, in his last clause, referred to a piece of a Pyro catalogue which has the following wording: NATIONAL ECONOMICS If we reckon the amount of inhabitants in our country to 6,000,000 people, making assumably 1,000,000 families, and we estimate that 1/10 of these – or 100,000 families – uses a paraffin stove appr. 3 hours per day with a fuel consumption of (according to official information) appr. 4 öre per hour will there be an annual consumption of appr. 21,100,000 litres of paraffin, which after a price of 18 öre/litre means a value of 4,338,000 Kronor If these paraffin stoves should be exchanged to stoves of the brand Pyro, which (according to official information) has a paraffin consumption of appr. 2 öre/hour, the annual need of oil for these would be appr. 12,400,00 litres of paraffin, which after a price of 18 öre/litre means a value of: 2,232,000 Kronor. This means that if only stoves from Pyro would be used, our country should annually make a pure saving of at least 2,100,000 Kronor.