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Webb Patent Sewer Gas Destructor Lamps


RichardB
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Dunn, Sarah (2008), Wilf noses out locations of old gas lamps, in The Diary, Sheffield Star, 16/July/2008

Not a link, more of a pointer to some more possible information.

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The gas lamps were designed to ventilate the sewers in the days when most houses were connected to the sewers by way of a "intercepting trap". This was located in a man-hole just inside the property boundary and was a source of constant trouble. Later on houses were connected directly to the main sewer with one sewer connection serving a number of houses and the sewer is ventilated via all the house "stench pipes" (soil pipes) which are open at the top. Atmospheric pressure variations cause a draught through the sewers. The bit of methane escaping from an un-capped gas lamp would be tiny compared to that ventilating from soil pipes at every house. I presume the gas supply to the lamps would have been disconnected when the gas mains were replaced for natural gas.

HD

That is correct, and probably explains why these sewer gas destructors were needed.

Gas from a soil pipe which is uncapped is always at the same pressure as the air outside and can vent freely into it. This is not good for global warming but is safe.

However, gas in sewer can become trapped in pockets and areas sealed by water, and if the gas is still being produced by decomposition of sewage pressure can build up causing a dangerous situation and a high concentration of gas which could form a flammable and explosive mixture wuth trapped air.

The destructor lamp would allow the pressure to be released and the gas to be safely burnt off.

As far as I know these lamps were not lit regularly like strret lamps and were only lit when the gas build up was sufficient to neccessitate it.

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As far as I know these lamps were not lit regularly like strret lamps and were only lit when the gas build up was sufficient to neccessitate it.

When I was a kid gas lamps were the norm except on the new estates and were controlled by clockwork time-valves. I guess they must have been 8 day or so clocks because you didn't see the bloke winding them very often. The sewer gas lamp at the junction of Kendall and Oakland road was lit 24/7. I used to pass it 4 times a day on my way to and from school.

HD

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When I was a kid gas lamps were the norm except on the new estates and were controlled by clockwork time-valves. I guess they must have been 8 day or so clocks because you didn't see the bloke winding them very often. The sewer gas lamp at the junction of Kendall and Oakland road was lit 24/7. I used to pass it 4 times a day on my way to and from school.

HD

There must have been a fair amount of excess gas in the sewers then, as it can be burnt off much faster than natural decomposition produces it (the same reason that we are now running short of fossil fuels).

Of course it would depend on the quantity of sewage, the "reservoir" of gas, the number of destructor lamps used and how quickly they consumed the gas as well as a number of less obvious variables, - such as the sewage temperature.

How big was the flame? Was it just like a "pilot light" or was it lighting half the street up?

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The sewer gas lamps were normally powered by towns gas as it was at that time. The methane from the sewers was inspirated into the gas-air mixture injected into the mantle flames. I think the enlarged cylindrical base would contain the necessary gubbins and would also probably contain a flame-trap to prevent a back-fire into the sewer. The inspiration would create a negative pressure in the pipe down to the sewer and suck up the methane/air mixture. I don't suppose that there would be much difference in the light if methane was present or not.

HD

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If, as has been said, some are still working then they must have been converted to run on natural gas. Also they must still be maintained by someone. I wonder who!!

I've seen somewhere on the t'internet that the ones at Nether Edge are maintained by the Nether Edge Neighbourhood Group.

The three lamps which are/were illuminated are all in that area. Perhaps the council pay the gas bill ?, they do light the street up (a bit).

HD

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I well remember the old gas lamps being replaced by low-pressure sodium lamps which must have been in the late fifties/early sixties.

The old gas lamps may have been a bit dim with between 2 and 4 mantles depending on how posh the district was, but at least the light from them allowed colour distinction.

The L.P. sodium lamps were almost monochromatic (2 closely spaced yellow lines only 0.6nm apart in the light spectrum).

This meant that it was very difficult to make out certain colours under their light.

L.P. sodium was used because they are extremely efficient and long lasting, most side streets were lit with 35 watt bulbs. They do however require additional control gear to operate and the early control gear consumed almost as much power as the lamps.themselves.

The early versions of the lamp used a separate vacuum jacket like a clear vacuum flask to allow the lamp proper to operate at a high enough temperature. Later versions use an integral jacket.

According to the t'internet an interesting fact is that the global manufacture of these lamps is confined to two firms in Britain.

HD

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The sewer gas lamps were normally powered by towns gas as it was at that time. The methane from the sewers was inspirated into the gas-air mixture injected into the mantle flames. I think the enlarged cylindrical base would contain the necessary gubbins and would also probably contain a flame-trap to prevent a back-fire into the sewer. The inspiration would create a negative pressure in the pipe down to the sewer and suck up the methane/air mixture. I don't suppose that there would be much difference in the light if methane was present or not.

HD

OK, so the lamp is actually burning normal gas all the time and the slow seepage of sewer gas is constantly mixed with it to burn it off.

That sounds wasteful of gas but actually makes good sense and is definately safe.

It would not be possible to regulate the supply and pressure of the sewer gas, but you could do that with the town gas, so using this system the town gas ensures that the sewer gas, regardless of how much, how little or what it's pressure is gets completely burnt away while the town gas remains a steady flame regardless.

Quite clever really.

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I well remember the old gas lamps being replaced by low-pressure sodium lamps which must have been in the late fifties/early sixties.

The old gas lamps may have been a bit dim with between 2 and 4 mantles depending on how posh the district was, but at least the light from them allowed colour distinction.

The L.P. sodium lamps were almost monochromatic (2 closely spaced yellow lines only 0.6nm apart in the light spectrum).

This meant that it was very difficult to make out certain colours under their light.

L.P. sodium was used because they are extremely efficient and long lasting, most side streets were lit with 35 watt bulbs. They do however require additional control gear to operate and the early control gear consumed almost as much power as the lamps.themselves.

The early versions of the lamp used a separate vacuum jacket like a clear vacuum flask to allow the lamp proper to operate at a high enough temperature. Later versions use an integral jacket.

According to the t'internet an interesting fact is that the global manufacture of these lamps is confined to two firms in Britain.

HD

I have mentioned sodium street lamps in another topic, - I think it was in "Those Gleadless Pictures" where the Herdings estate, built in 1959 had very early sodium lighting mounted on the outside house walls as the houses were terraced blocks running perpendicular rather than parallel to the street and the lights lit up the walkways / pavements used to access the houses. The early ones contained both neon and sodium, When they came on the neon immediately lit up red, the sodium didn't because it was too cold and needed to vapourise before it could ionise and give out it's characteristic yellow spectrum. With current flowing due to the neon the lamp slowly warmed up, often taking around 10 to 20 minutes, during which time the colour slowly changed to the sodium yellow. This was a source of fascination for us as kids and we would stand in the street at dusk to watch these new fangled yellow lights coming on.

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The early ones contained both neon and sodium, When they came on the neon immediately lit up red, the sodium didn't because it was too cold and needed to vapourise before it could ionise and give out it's characteristic yellow spectrum. With current flowing due to the neon the lamp slowly warmed up, often taking around 10 to 20 minutes, during which time the colour slowly changed to the sodium yellow. This was a source of fascination for us as kids and we would stand in the street at dusk to watch these new fangled yellow lights coming on.

Modern L.P. sodium lamps (SOX lamps) still have a filling (at slightly below atmospheric pressure) of neon gas with the addition of a small amount of argon. The original control gear comprised a "leaky" transformer to provide the several hundred volts necessary to start the discharge, the voltage then dropped as the sodium vaporised. This was very inefficient and modern fittings use a conventional choke ballast with a separate ignitor to provide the high voltage start pulse. The inside of the outer envelope is flashed with a rare metal to reflect heat back in to maintain the optimum temperature.

HD

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Thought we should have a photograph of it.

Flash Earth

Those old street lamps, both gas and electric, with the Corporation green painted cast iron standard always look so much better than the modern one which seem to be mounted on a tall concrete post.

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Here's a schedule of all the one's the Council are aware of and/or maintain

What a great, illustrated inventory list.

Looks like there are 25 of them then.

....unless we can find any more!

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Modern L.P. sodium lamps (SOX lamps) still have a filling (at slightly below atmospheric pressure) of neon gas with the addition of a small amount of argon. The original control gear comprised a "leaky" transformer to provide the several hundred volts necessary to start the discharge, the voltage then dropped as the sodium vaporised. This was very inefficient and modern fittings use a conventional choke ballast with a separate ignitor to provide the high voltage start pulse. The inside of the outer envelope is flashed with a rare metal to reflect heat back in to maintain the optimum temperature.

HD

Whilst being driven through Belgium overnight on our way to Germany on the Belgian motorways the driver related a story about why the Belgian motorways were the best lit roads in the World.

They are lit by sodium lights. The Government transport minister got it through Parliament that for safety the motorways should be lit by sodium lights at night, and, at public taxpayers cost, this work was carried out.

But the minister was not satisfied that the roads were light enough at night, and so ordered extra lights to be placed between the lights he had just had fitted and this was done.

Still not satisfied, he then ordered even more lamps to be placed between existing lamps increasing the number of lights per kilometre to 4 times the original density.

This work was started but was ended abruptly when the transport minister and his brother were arrested and charged with fraud, corruption and making financial gain from public money. This happened when it was discovered that the ministers brother had a factory making lamp standards and a civil engineering company for supplying and fitting them. All the contracts for these lights had gone to the ministers brother.

The Belgian motorways were nice and bright though.

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Superb indeed Dave, hopefully the best resource on the subject - the Great War Soldiers and the Pubs may have taken longer, but, excellence in any topic is to be applauded.

What a great, illustrated inventory list.

Looks like there are 25 of them then.

....unless we can find any more!

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There are a couple I think you may have missed.

Park Lane....near the Hallamshire Hospital....top end of Collegiate Crescent

Oakland Road....Hillsborough.

I have taken screenshots from Google Maps but sorry cannot seem to upload them. :unsure:

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There are a couple I think you may have missed. Park Lane....near the Hallamshire Hospital....top end of Collegiate Crescent Oakland Road....Hillsborough. I have taken screenshots from Google Maps but sorry cannot seem to upload them. :unsure:

Thanks julado

We already had Park Lane but it wasn't made clear where it was so I've edited the location in now

Here's the Google Streetview of the other one

Google Streetview - Oakland Road S6

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On the subject of Webb lamps, do you remember when Radio Hallam presenter Roger Moffatt painted the one on Brincliffe Edge Road red white and blue to celebrate the Silver Jubilee? It made all the papers!

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There used to be one at the bottom of Handsworth Hill in Darnall on the right hand side as you approached the Junction with Prince of Wales Road just outside what if I remember correctly was a newsagents ( though I can't remember the name of it). There was also a Dentist

My maternal Grandmother lived at Darnall (On Brittania Road) and 2 of my Great Aunts and a second cousin lived in three little 2 up 2 down terraced houses who's back gardens were entered by a gate in Beighton Street ( There front doors led straight into a small front area ( garden would be too grand a word to describe it) on Handsworth Hill. As a small child I remember that most of Darnall was still lit with Gas lamps and every evening at Dusk the lamp lighter would come round and light them all.

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The one at Darnall was removed when Prince of Wales Road was widened, (late '80's?) and the junction altered. It was carefully taken down and stored for re-use when the work was completed to be put up in a new position. Came the great day and it was transported back to site to be put up, but when lifting it off the lorry it cracked and fell to bits! Difficult thing to deal with being cast iron.

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