Musings of an Idiot
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- Full Steam Ahead
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Re: Musings of an Idiot
Many a mill engine had a notched quadrant set in the wall behind the flywheel so it could be "barred" over with a crow-bar, against the spokes. Sorry, don't have a pic to hand.
Retirement is about doing what floats your boat!
A BODGE : - A Bit Of Damn Good Engineering.
A BODGE : - A Bit Of Damn Good Engineering.
- fredrosse
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Re: Musings of an Idiot
A funny (and true) story about turning gears. Not too many years ago, almost all large ships were driven by steam turbines, and a 3 - 5 Horsepower turning gear motor was moved into position when the ship was shut down, and this kept the steam turbine continuously rolling over, avoiding thermal distortions, etc. If the main turbine was started while the turning gear was engaged, the several thousand horsepower steam turbine would destroy the small gearbox connected to the turning gear motor. Over the years many turning gears were destroyed. It became common practice to hang a large metal sign (with connected chain for hanging the sign) on the main steam throttle valve handwheels, in big letters stating "TURNING GEAR ENGAGED", so the operator would surely know to disengage the turning gear before starting the main turbine. Only after disengaging the turning gear, the sign could be removed and hung in its stowage position, away from the throttles.
As might be expected, turning gears continued to be destroyed with regularity, and the operator always had an excuse: "The turning gear engaged sign had not been mounted on the throttle handwheel, so I thought it OK to start the turbine". That excuse was used over and over through the years, but it wouldn't hold up at Electric Boat Works in 1969.
I was working there in 1969, and the engineering office overlooked the yard, with several nuclear subs being fitted out, repaired, etc. We often looked at the yard, especially when a submarine was coming in or leaving the yard. One afternoon a submarine was leaving the yard, began backing away from the dock, and the stern horizontal stabilizer fin backed right into a 120 foot tugboat, promptly sinking the tug.
The Capitan had given the order to back slowly, then gave the go ahead order to stop the sub, but for some reason the engine crew could not stop the turbine from going astern, hence the collision.
Turns out that, on this occasion, the “TURNING GEAR ENGAGED” sign and its chain had gotten tangled up in the main steam valve handwheels, so the engineer could not shutoff the turbine steam. One more turning gear destroyed. I wonder what excuse might have been used here, as the classic excuse “The turning gear engaged sign had not been mounted...” would not be accepted in this case!
As might be expected, turning gears continued to be destroyed with regularity, and the operator always had an excuse: "The turning gear engaged sign had not been mounted on the throttle handwheel, so I thought it OK to start the turbine". That excuse was used over and over through the years, but it wouldn't hold up at Electric Boat Works in 1969.
I was working there in 1969, and the engineering office overlooked the yard, with several nuclear subs being fitted out, repaired, etc. We often looked at the yard, especially when a submarine was coming in or leaving the yard. One afternoon a submarine was leaving the yard, began backing away from the dock, and the stern horizontal stabilizer fin backed right into a 120 foot tugboat, promptly sinking the tug.
The Capitan had given the order to back slowly, then gave the go ahead order to stop the sub, but for some reason the engine crew could not stop the turbine from going astern, hence the collision.
Turns out that, on this occasion, the “TURNING GEAR ENGAGED” sign and its chain had gotten tangled up in the main steam valve handwheels, so the engineer could not shutoff the turbine steam. One more turning gear destroyed. I wonder what excuse might have been used here, as the classic excuse “The turning gear engaged sign had not been mounted...” would not be accepted in this case!
Re: Musings of an Idiot
Ouch, Fred. That poor striker must have been hanging by his thumbs ...
Steve
- DetroiTug
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Re: Musings of an Idiot
Here is a device at the Henry Ford Museum to turn the big Corliss in case someone stops it at top or bottom dead center.

-Ron

-Ron
- Lopez Mike
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Re: Musings of an Idiot
In San Diego, CA., there is a retired steam ferry with a very dead boiler. They have hooked up a hydraulic motor to the jacking gear so that the docents can 'run' the engine. The hydraulic plumbing is rigged (I believe) to the reverse gear so that when the gear is swung over and the 'throttle' opened, the engine runs in reverse. All very slow and impressive.
How long that worm jacking gear set will last is hard to say. Low rpm and moderate loads may save it.
Mike
How long that worm jacking gear set will last is hard to say. Low rpm and moderate loads may save it.
Mike
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
Dalai Lama
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Re: Musings of an Idiot
Mike,
That's the Berkeley, one of my babies. The reversing engine is operated by air to move the way shaft and links. There is a Morse push-pull cable attached to the reversing engine valve gear that actuates the directional control valve to the hydraulic motor on the jacking gear. Another Morse cable on the throttle linkage controls the motor speed from zero to about 6 rpm. I put the cable system in a few years ago to replace a leaky system of hydraulic cylinders that was always getting air bound. I'm trying to talk the powers that be into letting me take the motor off the jacking gear and use it to turn the engine via the prop shaft with a chain drive. Rolling the engine at around 30 rpm would be far more impressive!
Chris
That's the Berkeley, one of my babies. The reversing engine is operated by air to move the way shaft and links. There is a Morse push-pull cable attached to the reversing engine valve gear that actuates the directional control valve to the hydraulic motor on the jacking gear. Another Morse cable on the throttle linkage controls the motor speed from zero to about 6 rpm. I put the cable system in a few years ago to replace a leaky system of hydraulic cylinders that was always getting air bound. I'm trying to talk the powers that be into letting me take the motor off the jacking gear and use it to turn the engine via the prop shaft with a chain drive. Rolling the engine at around 30 rpm would be far more impressive!
Chris
- Lopez Mike
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Re: Musings of an Idiot
This is the most amazing forum. I knew someone on here would be tangled up in that setup. The next time I'm down there I will be getting in touch with you.
Mike
Mike
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
Dalai Lama
Re: Musings of an Idiot
May I add my pennyworth?
It was common on large non-reversible (cotton or woollen) mill engines to have steam and/or electric barring gear, to move the crankshaft for maintenance or to the starting position. The flywheel had teeth inside or outside along one edge. The barring engine had a matching small gearwheel to engage the flywheel, but it was slide-mounted on a shaft with splines and a cam (or two). The barring gear was engaged by hand, sliding its gearwheel into engagement with the flywheel. The barring engine could be started, the main engine steam valve would be opened and, when the flywheel began to "overtake" the barring engine, the barring engine's gearwheel would slide out of engagement with the flywheel. All very safe, no problems. It was rather like the Bendix drive on a motor car engine starter. However, this arrangement could not be used on a reversible marine engine.
In this case a common arrangement was to have a worm on a (vertical) shaft mounted in a casting which could be manually slid across into engagement with teeth on a (fly)wheel on the engine crankshaft. When engaged, the crankshaft was locked solid, the worm being turned by a spanner or whatever on a suitable square end on top of the worm's shaft. Accidents surely happened - which is no doubt the reason for a broken lug on the worm casting of our Fleming & Ferguson compound!
It was common on large non-reversible (cotton or woollen) mill engines to have steam and/or electric barring gear, to move the crankshaft for maintenance or to the starting position. The flywheel had teeth inside or outside along one edge. The barring engine had a matching small gearwheel to engage the flywheel, but it was slide-mounted on a shaft with splines and a cam (or two). The barring gear was engaged by hand, sliding its gearwheel into engagement with the flywheel. The barring engine could be started, the main engine steam valve would be opened and, when the flywheel began to "overtake" the barring engine, the barring engine's gearwheel would slide out of engagement with the flywheel. All very safe, no problems. It was rather like the Bendix drive on a motor car engine starter. However, this arrangement could not be used on a reversible marine engine.
In this case a common arrangement was to have a worm on a (vertical) shaft mounted in a casting which could be manually slid across into engagement with teeth on a (fly)wheel on the engine crankshaft. When engaged, the crankshaft was locked solid, the worm being turned by a spanner or whatever on a suitable square end on top of the worm's shaft. Accidents surely happened - which is no doubt the reason for a broken lug on the worm casting of our Fleming & Ferguson compound!
- Lopez Mike
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Re: Musings of an Idiot
I have a number of signs hanging about in my shop. The one that causes a pause for reflection reads, "He was a good man but he didn't know about flywheels."
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
Dalai Lama
- artemis
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Re: Musings of an Idiot
"Sand Pebbles" with Steve McQueen - Remember the scene where the ancient Chinese "engineer" crawls into the crankpit to work on the engine. The jacking gear (which being worm drive also served as a locking gear) "jumped" a thread or two - or slipped on the crankshaft - due to a leaking throttle (or main steam stop valve) and allowed the crank shaft to partially rotate and crush said ancient Chinese "engineer". An excellent example of the results from "monkey see, moneky do" training. This movie had one of the most realistic small marine engine rooms I've ever seen. Somebody knew their stuff.