Hjorth ½pt Aetna (1894-5)

Discussion in 'Stove Paraffinalia' started by igh371, Nov 29, 2020.

  1. igh371

    igh371 SotM Winner Subscriber

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    It is well known how once Svenson had given marketing over to B.A.Hjorth the scale of the 'Primus' business and brand began to expand exponentially. One aspect of this was expanding from stoves alone to entering into competition with Sievert for the blowlamp market, whilst Sievert responded from the opposite direction. A chance find from a charity shop outlet shows a little more of the speed of these developments as well as shedding a little more light on the origins of the Primus '0' stove.

    Here is an exceptionally early ½pt Aetna blowlamp (Re-designated as model 631 after 1911). This new find can be dated by the early NRV apparatus and lack of any tank side logo to 1894/5. It also has the original, crescent shaped, Hjorth tank base provenance mark. This size of Hjorth Aetna blowlamp does not even appear in the 1898 catalogue, although examples which can be dated by external features to 1898-1908 are already known; including the Arabic script cartouche example used in some of the following photos for comparative purposes). In addition to the points noted above this remarkable new discovery also sports a unique male-threaded filler cap and an equally unique pump rod assembly, and the tank is taller, at 9.5cm, than the later 9cm high versions although the tank diameter is the same at 8cm:

    DSC00091.JPG DSC00085.JPG DSC00088.JPG DSC00086.JPG DSC00089.JPG DSC00090.JPG DSC00095.JPG DSC00096.JPG DSC00097.JPG DSC00098.JPG DSC00099.JPG DSC00100.JPG DSC00101.JPG DSC00102.JPG

    The fully shrouded blowlamp burner is the of pattern patented by Sevenson late in 1893:
    Svenson 1893 blowlamp burner patent-page-001.jpg Svenson 1893 blowlamp burner patent-page-002.jpg

    The 'mini' version of the type of early NRV assembly favoured by Svenson is all but identical to that used on the first small sized ('0') stoves introduced before the end of 1895 (see here). The only significant difference is the very primitive pump cup assembly found on this ½pt Aetna blowlamp. The non-floating leather cup has petal folds which allow it to contact slightly as it is drawn back up the tube. The side hole in the pump tube then allows a full charge of air to enter before the pressure stroke is made. There may be a possibility that his small diameter pump with the miniaturised NRV assembly was first made up for these first ½ pint blow lamps, then transferred, but with an improved pump, to the new model '0' stove.



    @kerophile @Christer Carlsson
     
  2. Tony Press

    Tony Press Australia Subscriber

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    Great post. Thank you, @igh371 . :thumbup:

    Cheers

    Tony
     
  3. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Ian , I am intrigued by the “petal” leather air pump.
    I have seen something similar in ancient bilge pumps for boats,although they work in reverse, lifting water on the up-stroke.

    In the US they are called “burr pumps” basically a cone-shaped leather bucket that drew water up a tube.

    On an old scottish vessel the cone shaped piston was made of greased canvas and operated in a vertical square-section wooden tube. The canvas piston folded on the down stoke, opened up in the water, inside the bottom of the tube, and was then drawn upwards in the tube and the water was discharged through a spout near the top.

    Your’s is a great find and a nice commentary.

    Best Regards,
    George.
     
  4. Lennart F Sweden

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    That makes my two 1895-96 Aetna's look quite modern!
     
  5. ROBBO55

    ROBBO55 Subscriber

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    Nice find and an interesting post, Thanks :thumbup: