There was an unofficial race to produce a functioning, safe and accurate system of pressure measurement in the 1840s. The huge increase in the use of steam in all walks of life was emphasising the safety issues involved with exploding boilers, whether they were on trains or stationary engines in textile mills or steam ships. Mechanics and opticians across the developing world were in their workshops testing new ideas and trying out a variety of new systems to measure pressure accurately. Accuracy was the key, something that was not occurring with the old ‘Mercury Bob’ style of pressure measurement.
You might wonder why opticians were part of this development, but many instrument makers started their lives in optical workshops. The need for accuracy and working to fine measurements was part of their apprenticeship in the optical trade, and a fair number went on to work with scientific instruments such as Bernhard Schäffer whose company produced microscopes and slides.
Schinz was Swiss born, but spent much of his life working around Europe as a civil engineer, mainly building bridges. He was however, multi-talented. It appears he never actually patented his gauge design outside of Switzerland and Austria. They started being commercially produced in 1845 for use on railways in the German Federation and Prussia, the success of which was reported in the British weekly newspaper „The Engineer“berichtete über die Erfolge dieser Geräte. Bourdons Messgerät, welches von allen vier Entwürfen die kommerziell erfolgreichste wurde, basierte auf Schinz Arbeit. In Deutschen Bund und in Preußen waren Bourdon-Messgeräte wegen des speziellen Innenrohrs bis weit ins 20. Jahrhundert hinein als "Schinz-Typ" bekannt.th century, because of the inner tube. Sydney Smith’s gauges were taken up and promoted by George Stephenson and used heavily in mines, mills and railways. His gauge followed by improvements to the original design meant a busy factory producing for the railway companies. Smith always promoted himself as the der erste Patentinhaber eines Druckmessgeräts zu sein - Patent Nr. 11711 aus dem Jahr 1846 - was in Großbritannien auch stimmte.
https://www.railwaysarchive.co.uk/docsummary.php?docID=2349
Vielen Dank an Pete Skellon für diese Informationen und den Link.
Da im Hintergrund Lastwagen der Firma Verdin Cooke & Co. mit Sitz in Winsford, Cheshire zu sehen sind. Es handelt sich um Lastwagen, die Salz aus den vielen Salzminen der Gegend transportierten.
Diese Grundlagen in der Optik und die neuen Möglichkeiten, um feinste Geräte zu produzieren - was wenige Jahrzehnte zuvor nicht möglich gewesen war - ebnete den Weg für Präzision in der Messtechnik. Vier Männer produzierten innerhalb von vier Jahren (1845-1849) gute Messgeräte, die patentiert und in der Industrie nutzbar waren. Viele andere Erfinder waren ihnen auf den Fersen, aber nur diese vier waren erfolgreich. Es handelt sich um:
Eduard Schinz (1812-1855) aus Zürich, Schweiz,
Sydney Smith (1803-1882) aus Nottingham, in England,
Eugène Bourdon (1808-1884) aus Paris, Frankreich und schließlich
Bernhard Schäffer (1823-1877) aus Magdeburg, Preußen.
Bernhard Schäffers Konstruktion war ganz anders als die Kapselrohrkonstruktionen von Schinz und Bourdon und hatte mehr Ähnlichkeiten mit der von Smith. Beide Messsysteme nutzten die Auslenkung durch ein Diaphragma. Schäffers Gerät besaß eine Tellerfeder, die sich auf und ab bewegte und den Vibrationen auf Lokomotiven sehr gut widerstand - im Gegensatz zu den frühen Quecksilbermanometern. Später ergaben sich für diese Art von Messgeräten eine Vielzahl neuer Anwendungen, insbesondere als die chemische Verarbeitung und die Konservierung von Lebensmitteln alltäglich wurden. Die Tellerfedern konnten mit verschiedenen Materialien beschichtet werden, die von den zu messenden Chemikalien nicht angegriffen wurden oder die Lebensmittel, die konserviert wurden, nicht verunreinigten. Der Patentantrag für Schäffers Messgerät wurde 1849 eingereicht und am 18. Januar 1850 wurde die Konstruktion offiziell patentiert.
During the period of Bourdon’s development of his gauge – which lasted some years – the man who eventually produced it commercially for him was also working on pressure gauge designs. This was Felix Richard in Lyon. I think it is fair to say that the English speaking world has little knowledge of French inventors and scientists, but they were often ahead of the British, and were more often stymied by French bureaucracy than anything else – which continued to be the case when the French were building their railways, and led to their downfall in the Franco-Prussian war. (The Prussians took their troops to the front line by train!) Lucien Vidie (1805-1866) who had developed an aneroid barometer with a dial scale took Bourdon to court in a protracted legal battle (six years) which he won, because his barometer worked on a very similar style to Bourdon’s pressure gauge. Bourdon’s tube was a variant of Vidie’s capsule internally, although it would appear that Schinz also used some of Vidie’s ideas. As Schinz never patented it across wider Europe there was no court case to answer.
Eines der frühesten Patente für ein Dampfmessgerät wurde 1835 in den USA von Enos Allen angemeldet. Allerdings handelte es sich dabei eher um einen Schmelzstopfen als um irgendeine Art von Messgerät, und obwohl Allen es schaffte, die US-Regierung dazu zu bringen, es insbesondere für alle Dampfschiffe verbindlich zu machen - er dachte bei der Entwicklung dieses Artikels an die Mississippi-Raddampfer -, wurde es bald überholt.
Bourdon nahm seine Erfindung 1851 mit nach London zur Weltausstellung im Kristallpalast, wo sie von allen Besuchern wegen ihrer Einfachheit in Design und Anwendung bewundert wurde.
Edward Ashcroft, a young Irish-American visiting the Great Exhibition bought the rights to produce the Bourdon gauge in the States and it was in production over there by 1852. He made ‘improvements’ and re-patented the gauge but his improvements were not as good as they could have been. The advantage of making an ‘improvement’ to a patent meant that all the money would go to Ashcroft rather than a royalty to Bourdon. Ashcroft went on to become an extremely successful businessman and whose company still continues to this day, although part of a much larger conglomerate, but still operating under its own name.
Bernhard Schäffer and Christian Budenberg did not have the funds to go to the Great Exhibition in London in 1851. They had started their business a year previously and like many new start-ups were suffering from lack of funds for anything except the essentials.
Having enough money to buy the raw materials to make the gauges was causing problems, and they relied on loans from family members to keep going. In the early days they relied on income from contracts to make optical and scientific equipment for Engells & Co. in Switzerland and Georg Oberhauser in Paris. However, in later exhibitions the Schäffer gauge won many medals. Both the Bourdon and Schäffer gauges are still produced in vast quantities today which shows that simplicity of design and function stand the test of time.
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