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Wolf-Fleissner “Singing” Safety Lamp No. 713

The Wolf-Fleissner No. 713 is considered one of the most desirable safety lamps among collectors because of its unusual design and rarity.  The 713 looks very different from the 712, but the internal sounding system is basically the same.  As indicated on the advertisement below, the 713 was designed for taking methane readings from overhead in confined spaces.  The lamp was built heavy duty, and is totally enclosed to protect from dripping water.  The prism, used to view from above the lamp, is typical of other Wolf lamps made for the same purpose,

“First check from above with the acoustic-optical test lamp”, Says this Friemann & Wolf 1933 advertisement.

Click images below to view other Wolf-Fleissner “Singing” Safety Lamps:

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Wolf-Fleissner “Singing” Safety Lamp Model 712

Having a corrugated bonnet, Wolf’s Fleissner lamp number 712 was designed more in line with Friemann & Wolf’s standard safety lamp for underground use.  Introduced about 1925, the lamp was advertised along with model number 713, although whether the 712 & 713 was manufactured concurrently with the 1923 model is questionable.

Sectional view drawing patent No. 410038 February 18, 1925.

Click on the images below to see more Wolf-Fleissner “Singing” Safety Lamps:

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Wolf- Fleissner “Singing” Safety Lamp- 1923 Patent

This model is identical to the German 1923 patent and differs in various ways compared with model number 712 & 713.  While this example is unmarked, there have been specimens found with Wolf Safety Lamp of America, and Wolf Leeds.  There are at least two (2) examples of this model made of aluminum, and marked with Wolf Safety Lamp of America.  Judging from an American advertisement (see right), it appears that this was the first commercial model to be exported.  The advertisement indicates other models to be introduced, but American advertisements with the additional models have not been found.

From Wolf Safety Lamp Of America Advertisement.

Sectional view of singing Wolf Fleissner lamp. Patent No.
387506 drawing; December 29, 1923.

Click on the images below to see other Wolf-Fleissner Singing Safety Lamps:

                                                                       

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Hans Fleissner’s “Singing” Safety Lamps

Drawings of Fleissner lamps from 1926 Friemann & Wolf catalogue. Note that while No. 714 is a Fleissner lamp, it is not a “singing” lamp.

The Fleissner lamp, or otherwise know as the “Singing” safety lamp, was the first practical attempt to provide an audible warning from a flame safety lamp in the presence of firedamp. The lamp’s inventor, Hans Fleissner (1881-1928), came from a mining family in Bohemia. He was born in Zwodau near Falkenau-on-Eger, and eventually received a doctoral degree from Prague’s technical university. After World War 1, he was a professor at the famous Leoben Mining University. He died in Karlsbad on June 15, 1928.

Fleissner worked at the Royal Mining Institute at Bruex from 1910 to 1918. At the Royal Mining Institute, he was responsible for investigating methods for preventing firedamp explosions and other dangers in the mines. While at the Royal Mining Institute, Fleissner developed the idea for an audible safety lamp around 1915, and was granted a patent on October 6^th, 1916. In the Volume 7, 1917 edition of Bergbau und Hutt, Fleissner describes the principal of his lamp as follows:

“a flame in a certain position within a hollow body, open at both sides, is able to produce a sound if the flame rises due to the presence of firedamp.”

Fliessner’s benzene experimental lamp.  

Around 1916, Friemann & Wolf manufactured two experimental “singing” lamps. One was fueled by benzene, while the other was a carbide safety lamp burning acetylene. Fleissner discovered that the benzene model could detect methane from .5 to 5%, and was more sensitive in detecting firedamp than the acetylene model. But, the acetylene model produced a much stronger sound. (The original benzene test lamp can be seen at the German Mining Industry Museum, in Bochum, Germany.)

Fleissner and Friemann & Wolf obviously felt the experimental lamps were a success, and that there was a need for a combination acoustical and optical safety lamp in the European coalmines and in other industries. While many variations were produced, Friemann & Wolf made three (3) distinct, benzene models of Fleissner’s “singing” lamp (Note: the author does not know of any acetylene models in existence). Judging from various Friemann & Wolf catalogues, “singing ” lamps were produced until the early 1930’s.

1923 Model. Click to enlarge.

As with most Friemann & Wolf lamps, the engineering and construction of the “singing” lamps were excellent. Judging from patents and advertisements, it appears that the first production model was the 1923 patented design(The author has not been able to identify the Wolf model number for this lamp). Model numbers 712 and 713 apparently came a few years after, possibly in 1925. It is interesting to note that models 712 and 713, while looking very different in design, are similar in regards to the internal design of the sounding system. There are slight differences in the 1923 design, compared with models 712 and 713. While the 712 and 713 were commonly shown together in Friemann & Wolf catalogues, the author has not been able to locate any documentation showing all three models. It is possible that the 1923 model was discontinued around 1926, and not produced concurrently with 712 & 713.

Model Number 712. Click to enlarge.

The 712 design is based off the basic Wolf lamp fitted with a corrugated bonnet, and was probably used for general underground firedamp detection. The 713 is heavy duty, totally enclosed, and fitted with a prism for observing the flame from above the lamp. It was designed for lowering down in holes and low places to measure and detect firedamp. Being totally enclosed, the lamp was well protected from dripping water and bumps from obstructions.

Model Number 713. Click to enlarge.

It is interesting to note that there are a few examples of the 1923 variety that were obviously made for the US market (see advertisement). It is a made of all aluminum, and is tagged similar to other German-made Wolf lamps for the US market. Also, there exists at least one 1923 example with a Wolf-Sheffield brass tag on it. Did the 1923 model end up being used for the export market?

It appears that most of these lamps were used in Eastern Europe, especially in the Austro-Hungarian area. While few made it to the US, there is one variety that targeted the US market. It is a 1923 variety made of all aluminum, and is tagged similar to other German-made Wolf lamps for the US market.

Even though Friemann & Wolf produced many varieties of “singing” lamps for almost twenty (20) years, relatively little information is known today about the development, applications, and performance of Fleissner’s lamps. Many people have explained the rarity of the “singing” lamps as having limited use because under noisy conditions, the lamp’s sound couldn’t be heard. While this might explain its limited use, there must have been a distinct niche for this type of lamp judging from the length of production and number of models and variations. The complete story of Fleissner’s “singing” lamp has yet to be told. Much of it probably has been lost to time.

No. 714. Fleissner’s non-“singing” lamp.

While Fleissner is best known for his acoustic-optical safety lamp, he did patent another safety lamp design that was also produced by Friemann & Wolf and was designated as model 714. While the 714 looks like a small version of Wolf’s 713 lamp, it is not a “singing” lamp. It is more like a “baby” version of the Beard-Mackie sight indication system. The lamp is designed with a ladder system with platinum wires located over the burner. The lamp also has an unusual gauze cooling system that appears to have designed to dampen the velocity of the burnt gas within the lamp.

For additional photos and information, click on thumbnails below!

References:

Wolf-Fleissner ” Singing” Safety Lamps, Manfred Stutzer, Eureka!, January 1995, Issue 13.

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Early Clowes’ Hydrogen Oil Lamp

This is the earliest of Clowes’ Hydrogen Oil Lamp and the one that most resembles the drawings in the patent.  It is very eloquently made with the precision of an instrument. The maker, Stanley of Derby, was well know for surveying instruments.  The lamp is marked “Ashworth’s Patent  Hepplewhite Gray  Stanley Derby”.  The cylinder is very nicely engraved “Clowes & Redwood’s Patent  W. J. Fraser & Co.  Commercial Road East  London”.  W. J. Fraser was most likely a specialist in  manufacturing gas cylinders.

Again, the construction of this lamp is like an instrument.  The cylinder is attaches to the lamp font via a bayonet system.  The cylinder “snaps” and is locked into a spring loaded mount at the base of the bonnet.  There is not prevision in this design to realign the cylinder mount on the font, and the cylinder mount on the bonnet when font’s thread starts to wear.  Note that, unlike other Ashworth lamps, that there is only one shut off sleeve mounted on a standard instead of the usual two.  This example is unfired, and is circa 1892 to 1900.

Click the thumbnail to see the next lamp.

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Clowes’ Hydrogen Oil Lamp

Although the Clowes’ Hydrogen Oil Lamp should probably be categorized in the Ashworth-Hepplewhite-Gray section, the uniqueness and ingenuity of this lamp calls for its own special section.

The need to be able to accurately measure levels of firedamp in minute concentrations became more and more of a necessity as ventilation  became more complicated in deepening mines.  The standard Davy lamp fell way short of being a useful instrument for measuring low levels of firedamp.  Towards the end of the 1800’s, several people in England and in Europe were working on the problem utilizing the basics of the Davy lamp.  The Pieler Lamp was introduced in Germany about 1885, and was probably the first commercially made device that could accurately measure small amounts of firedamp.  While used extensively in Europe, it had its drawbacks and didn’t see much use in England.

On March 29, 1892,  James Ashworth of Morely, and Frank Clowes of Nottingham filed a patent application (No. 6051) for “Improvements in Miner’s Safety Lamps”.  Basically, the patent was covering the idea of installing a hydrogen gas burning device in any ordinary safety lamp to be utilized in gas testing.  Ashworth and Clowes were capitalizing on the fact that a hydrogen flame gives a hot non-luminous flame, and therefore a large testing flame can be used and larger and plainer caps obtained for easy reading.  The patent covers two methods of delivering hydrogen to the burner: 1) Compressed hydrogen contained in a separate vessel or in a receptacle attached to the lamp, and 2) hydrogen directly from generating device.  It is interesting to note that while the patent drawings show these devices on Ashworth-Hepplewhite-Gray lamps, there is no mention of any particular lamp in the patent text.

What evolved into commercial use based on the patent was a modified Ashworth-Hepplewhite-Gray lamp with a detachable external cylinder for compressed hydrogen.  The lamp would use an oil flame for detecting methane down to 2 1/2%.  Below that, the hydrogen gas was turned on via the cylinder valve and the burner lit by the oil flame.  The oil flame would then be extinguished, and the hydrogen flame would be standardized to 0.4 inch tall.  The tips of the blue caps would be observed in comparison to the rungs on a vertical ladder scale.  Very accurate results could be obtained in atmospheres from 0.25% to 3% firedamp.  After the test was completed, the oil wick was ignited using the hydrogen flame, then the hydrogen gas was turned off and the cylinder detached.

The Clowes lamp was used from about 1892 to the 1920’s.  The lamp did not get approval to be used in “safety-lamp” mines when the approval system for mine lamps was in place. 

The lamp had many advantages over the Pieler lamp.  First, it could be used in atmospheres that contained above 2 1/2% firedamp.  Second, it could tolerate higher air current velocities safely.  Third, it could be used as a source of light.

To see two examples from my collection, click on the thumbnails below.

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Standard Clowes’ Hydrogen Lamp

This style of Clowes’ Hydrogen Lamp was the  most common variety used.  It has several differences compared to the earlier version.  While larger and more heavier duty, it is not made as precise.  The major changes are in the way the cylinder mounts.  First, the gas connection to the font is a threaded locking system instead of a potentially troublesome bayonet system.  The cylinder mount below the bonnet is a simple notched bracket instead of a spring loaded device.  Also, notice that the mount is adjustable to account for thread wear.  In short, this design was obviously more practical for rough service then its predecessor.

The only marking on this lamp is on the cylinder.  It is marked with a stamped brass tag that reads “Clowes & Redwood’s Patent  W. J. Fraser & Co.  Commercial Road East  London”.  The lamp portion was probably made by Stanley of Derby.  Circa 1900-1920.

Click the thumbnail to see the next lamp

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Biography

I have been buying, selling, and collecting miner’s lamps for about 25 years.  I can still remember the first miner’s lamp I bought that got me hooked on collecting.  It was a carbide lamp that cost $6 in Sierra City, California.  Of course, I learned later  that the lamp was a mixture of Auto-Lite and Justrite parts!! I think we all have a story like that.

My personal experience in the mining industry is not measured in years, but weeks.  When I graduated from the University of Arizona in 1984 with a degree in Mining Engineering, the copper industry had almost 50% unemployment and wasn’t in need of my valuable services.  So, I took a job with a scrap metal recycling company owned by a steel company that utilized 100% scrap to make new steel.  I became a modern-day “Fred Sanford”.  My main claim to fame was the engineering and construction of 3 large automobile shredding facilities.  Automobile shredders are basically hammer mills, but instead of rock, junk cars were fed into them.  The cars would be shredded into fist size pieces, and a downstream system would separate out the ferrous and non-ferrous metal, and non-recyclable material.  The machines I installed ate 1-2 cars PER MINUTE.  

Jennifer Findley and myself with US Ambassador Pete Peterson.  Photo taken in Ho Chi Minh City (Sai Gon) at the new Consulate located where the old US Embassy once stood.  Pete Peterson spent several years as a POW in the infamous “Hanoi Hilton”. 

After spending over 12 years in the scrap business, I decided to go to graduated school on a full-time basis to earn an MBA.  Since  graduating in May of 1999, I have been to Vietnam twice on special market research projects to investigate future trade opportunities.

Collecting has change significantly.  Back in the 1970’s, it was very difficult to find information about miner’s lamps. It was also very hard to find lamps.  Back then, collectors did not sell duplicate lamps but only traded.  This is because cash prices on lamps did not reflect their true value.  Needless to say, trading was difficult because you had to find something the other collector didn’t have, which was usually something you didn’t have in your collection either.  Because the prices now reflect the true value of lamps, more and more specimens now show up.  With the advent of Ebay, it is obvious that mining items are not as rare as we thought they were.  Its just a matter of price now…….

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Links

The following list contains links to other collectors of mine lighting devices and mining related artifacts.  If you would like me to include your link, send me an E-mail!

Manfred Stutzer-Collector of miner’s flame safety lamps located in Germany.  Manfred has one of the top collections in Europe, and his homepage contains a lot of neat information and photographs.

Dr. Hartwig Büttner-German collector of frog lamps.  Hartwig has many excellent photographs of Harz type frog lamps in his homepage.

Marcel Humbert-Labeaumaz-French collector of miner’s lamps.  Marcel has good historical information and pictures.  Much of the text is in French.

Andy Martin and Tino Romero-Excellent source of information on blasting cap tins.

Rauleigh Webb-Australian collector.  His homepage is an excellent source of information about carbide lamps from down-under.

Len Gaska-US collector of all types of mine lamps.

National Association of Mining History Organisations-Formed in 1979 at act as the national body for mining history in the UK and Ireland.  They have about 50 member organizations, including societies, museums, firms, etc.  

The Kentucky Coal Mining Museum-The Kentucky Coal Mining Museum is located in the former coal camp town of Benham in Harlan County Kentucky.

National Coal Mining Museum/England-England’s official coal museum.  A must see when in England.

Sir Humphry Davy-Short biography on the inventor of the Davy lamp.

Sir Humphry Davy-Another short biography of Davy.

Karl Heupel-German collector specializing in German carbide lamps from Siegerland,  Nordrhein-Westfalen.  Lots of nice photos, and information on German mining museums.

Souterrains-One of the largest databases on man-made underground information on and off the Internet.  Information about underground mining and tunneling from all over the world.

Schäfer Versand-Dealer in high quality reproductions of miner’s safety lamps made by Thomas & Williams, Friemann & Wolf, and The Protector Lamp Company.

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Justrite Sign

1915 Metal Advertisement Sign

Three-color lithograph.  Fully embossed metal.  Measures 11 1/2″ by 16 1/2″.  Great for framing!

$49, postage included.  To order, send email to davegresko@minerslamps.net