Author Topic: Gas Works  (Read 210 times)

Offline Lutonman

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Re: Gas Works
« Reply #31 on: January 03, 2021, 07:07:15 PM »
Good to hear Stewie,


We once had a bomb scare at a site and I arrived to see Police cars inside the boundary of the site. The inspector asked what was needed and I said get those cars our first as if the holder goes up so would the cars and their occupants. He was very quick to get them out. Next the police dogs arrived and they expected to send the dogs up on their own. When I explained the construction of the water grips at each level and that in the darkness the dogs will fall through into the tank, that idea was give up as well.




Offline Stewie

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Re: Gas Works
« Reply #30 on: January 03, 2021, 05:00:01 PM »
I have to say that I have learnt something reading this thread and the associated Wiki links!  :)

Offline Dave Smith

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Re: Gas Works
« Reply #29 on: January 03, 2021, 01:38:21 PM »
For anyone complaining about the constant GtheP thread- not me- the "gas" subject has been very active for some time with lots of interesting articles. So enjoy. And thanks to all those who contributed.

Offline MartinR

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Re: Gas Works
« Reply #28 on: January 02, 2021, 09:08:30 PM »
See https://en.wikipedia.org/wiki/Gas_holder in particular the illustration https://en.wikipedia.org/wiki/File:Dip_and_cup.svg shows how the seal was created and maintained as the parts rose and fell.

Offline Lyn L

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Re: Gas Works
« Reply #27 on: January 02, 2021, 08:54:04 PM »
Not having a clue about how gas holders work ! just being so used to seeing them in different places. As a young child living in Ramsgate we lived fairly near the Gas works and it always stank of gas. I always thought it was a usual smell of the town   8) .
My eldest son used to work at Grain for Transco later National grid and he has photos of himself inside a gas holder, he said he'd try and find any and let me know. 

Offline stuartwaters

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Re: Gas Works
« Reply #26 on: January 02, 2021, 07:13:48 PM »
Coal Gas has a very distinctive smell and I remember that as a young child while going to the Strand some years after the conversion to Natural Gas, the place still stank of Coal Gas.
"I did not say the French would not come, I said they will not come by sea" - Admiral Sir John Jervis, 1st Earl St Vincent.

Offline Lutonman

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Re: Gas Works
« Reply #25 on: January 02, 2021, 06:44:50 PM »
Here is newish picture of the spiral guided holder at Gillingham just after painting.


 

Offline Stewie

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Re: Gas Works
« Reply #24 on: January 02, 2021, 05:25:59 PM »
Stewie,
They did /do not work that way, in fact the opposite. The higher the holder the higher the pressure is created (known as thrown). But the difference in pressure when a holder is full to when nearly empty is not a great deal. Typically pressures were measured in inches water gauge and a full holder on a 3 /4 lift holder would be 12"wg, but as it emptied down to 4" wg. District pressures in those days were much lower as cookers/ fire etc could cope with the lower pressures. Modern boiler just wont work with those type of pressure.
The whole gas supply system was stood on it's head with the advent of Natural gas arriving already being at higher pressures and the job was then to reduce the pressure to a manageable one for the district gas mains. Previously compressors were used to allow the use of medium pressure pipes around town and between the towns. For instance Medway still has a medium pressure 18"ring main now largely replaced by PE pipes originally operating at 20 psi (the maximum allowed for cast iron mechanical jointed pipe). Chatham Dockyard had its own 9" steel pipework fed from both Gillingham and Rochester but only at 5 psi.


Thinking about it, if the collapsing telescopic cylinder created pressure in the outlet pipe then it would also need some sort of compressor arrangement to pump it back up again.

Offline Lutonman

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Re: Gas Works
« Reply #23 on: January 02, 2021, 03:51:38 PM »
Thanks for the detail Johnfilmer, not my area being a gas distribution pipe man.

Offline johnfilmer

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Re: Gas Works
« Reply #22 on: January 02, 2021, 03:20:07 PM »
The older gas appliances had multiple individual gas jets, often with their own aeration. All of those either had to be replaced when being converted, or the whole gas train may have been upgraded to a more adaptable box style burner. These had only a single injector per burner, easily swopped over on conversion.


Most conversions for common appliances were in kit form, easily fitted by the retrained, non gas industry workforce. My old business partner was a charge hand on conversion, and having a gas background was usually tasked with converting the uncommon, known as ad hoc conversions, as he made up the conversion from the piles of bits in the van.


Some cookers water heaters and fires could not be converted, those lucky souls got a replacement refurbished, or even new appliance.


I was running a heating service department from 1972 and we just caught the end of conversion, by which time they generally knew what they were doing. Boilers were frequently supplied in the wrong gas by builders merchants. I’m sure they did it just to cause mayhem.

Offline Lutonman

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Re: Gas Works
« Reply #21 on: January 02, 2021, 03:12:39 PM »
MartinR,
Yes on conversion the burning power (Calorific Value) of Natural gas was different to Town gas and quite a number of other characteristics were also different, so new burners were needed. Now days the industry knows more and can convert the gas itself. Just a few burners were able to cope with the two types of gas.

Offline MartinR

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Re: Gas Works
« Reply #20 on: January 02, 2021, 02:47:19 PM »
@LutonmanWhen we were converted to natural gas the burners on the cooker had to be replaced (free) and I think some of the gas fires needed "rejetting".  More modern equipment was dual fuel (natural/town), I don't know how that worked.  We didn't have a boiler in those days.

Offline Lutonman

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Re: Gas Works
« Reply #19 on: January 02, 2021, 01:59:22 PM »
Stewie,
They did /do not work that way, in fact the opposite. The higher the holder the higher the pressure is created (known as thrown). But the difference in pressure when a holder is full to when nearly empty is not a great deal. Typically pressures were measured in inches water gauge and a full holder on a 3 /4 lift holder would be 12"wg, but as it emptied down to 4" wg. District pressures in those days were much lower as cookers/ fire etc could cope with the lower pressures. Modern boiler just wont work with those type of pressure.
The whole gas supply system was stood on it's head with the advent of Natural gas arriving already being at higher pressures and the job was then to reduce the pressure to a manageable one for the district gas mains. Previously compressors were used to allow the use of medium pressure pipes around town and between the towns. For instance Medway still has a medium pressure 18"ring main now largely replaced by PE pipes originally operating at 20 psi (the maximum allowed for cast iron mechanical jointed pipe). Chatham Dockyard had its own 9" steel pipework fed from both Gillingham and Rochester but only at 5 psi.

Offline Howardws

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Re: Gas Works
« Reply #18 on: January 02, 2021, 07:55:02 AM »
I think that assumption is correct, after all the pressure was very low. The present high pressure system has all been installed since the advent of natural gas. My brother built a steam boat years ago and the boiler barrel was made of a short piece of gas main pipe begged off the men installing the main near his home. The boiler operated at 120psi but the barrel would have been safe for many, many times that pressure.

Offline Stewie

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Re: Gas Works
« Reply #17 on: January 01, 2021, 06:59:28 PM »
Ah! I had always assumed that the concertinaing effect of the collapsing gasometer pressurised the system.