Topic: Now this is a STEAM Plant something to aspire too.....what (Read 34535 times)

Steamer · « **Reply #50 on:** August 21, 2009, 03:11:43 am »

Thanks Oldiron.....got any shots of the rest of your boat?

Dave

Martin (Admin) · « **Reply #51 on:** August 21, 2009, 09:31:03 am »

Likewise, thanks Oldron, very interesting.
I was expecting roller trust bearings but with such a large lubricated surface the actual PSI (correct units?) would actually be quite low..... yes?

oldiron · « **Reply #52 on:** August 21, 2009, 09:44:51 am »

Here's the rest of the vessel. She runs a triple in a 94 foot hull built in 1915. She was commissioned by one of Canada's financial elite, Timothy Eaton. The vessel has a composite hull. That is, its wood below the water line and steel above.
The engine looks a bit messy, but I took the picture after I'd finished reassembling her from a complete tear down.

John

Steamer · « **Reply #53 on:** August 21, 2009, 12:21:46 pm »

aHH YES the "Wanda" I have seen pictures of her before...you should put up a thread on her.

I am sure many here would love to see her.

Thanks for that!

Dave

oldiron · « **Reply #54 on:** August 21, 2009, 12:24:53 pm »

Quote from: Steamer on August 21, 2009, 12:21:46 pm

aHH YES the "Wanda" I have seen pictures of her before...you should put up a thread on her.

I am sure many here would love to see her.

Thanks for that!

Dave

Perhaps I will. I'm off to the UK this morning, for about three weeks. I'll look into it when I get back.

John

Steamer · « **Reply #55 on:** August 21, 2009, 12:25:59 pm »

And yes Martin the actual pounds per square inch would be low and with proper lubrication, so is the friction.

There was mention of the pressure used with Titantic as being 1700 psi.steam pressure.....No. Probably more like 200 psi steam pressure

The USS Ohio which was contemporary, was a fast ship with high specific output for the weight of machinery...for its time...and her 4 legged triple ran at 250 psi.

Dave

BarryM · « **Reply #56 on:** August 21, 2009, 01:50:20 pm »

Quote from: oldiron on August 20, 2009, 07:26:43 pm

Steam turbines also use barring gears to turn the turbine over at slow speed when steam is shut off. This allows the turbine rotors to cool evenly and not hog. the same applies on startup. The turbine is put on barring gear well ahead of steam admission (several hours in many cases), this takes the droop, or sag out of the shaft to reduce vibration to within acceptable limits when steam is applied. When steam is admitted the turbine runs up and rolls off the barring or turning gear as rotor speed increases.
Before starting turbines, even on barring gear, lubrication oil is forced into the bearings under pressure to lift the shaft on a film of oil. This is done with high pressure jacking pumps. The jacking pumps continue in operation until there is enough turbine shaft speed to form a reliable oil wedge between the shaft journal and the bearing. I would expect a large marine engine such as that pictured would have a similar arrangement.

John

I wouldn't stay around to see the affect of shutting off the lub. oil pump supply to turbine bearings. Oil is always supplied to the bearings under pressure and once rotating, the shaft creates the oil wedge. The oil supply not only lubricates the bearing, it also cools it and the oil, once it has passed through the bearing, drains back to the sump.

Shutting off the lub pump should cause the turbine to trip-out on the low-pressure trip. Should the trip not operate the bearing would empty, the shaft would drop and contact the white metal bearing which would then overheat and cause the white metal to run. Thereafter there would be much lamentation and cursing as engineers turn-to to fix it.
Normal lub oil pump discharge pressure as I remember was about 30psi.

In respect of the thrust block depicted in the Titanic engine model, thiat type of multi-collar installation became obsolete once Mr Michell invented his tilting bearing pads and the thrust collar was reduced to a single piece. Setting up a muti-collar thrust block must have been a bit of anightmare. The tilting bearing pads in the new Michell thust block allowed an oil wedge to form between the shaft collar and the bearing thus greatly increasing their load-bearing properties and removing the need for multiple collars/bearing rings.

Barry M

oldiron · « **Reply #57 on:** August 21, 2009, 01:55:27 pm »

Quote from: BarryM on August 21, 2009, 01:50:20 pm

I wouldn't stay around to see the affect of shutting off the lub. oil pump supply to turbine bearings. Oil is always supplied to the bearings under pressure and once rotating, the shaft creates the oil wedge. The oil supply not only lubricates the bearing, it also cools it and the oil, once it has passed through the bearing, drains back to the sump.

Shutting off the lub pump should cause the turbine to trip-out on the low-pressure trip. Should the trip not operate the bearing would empty, the shaft would drop and contact the white metal bearing which would then overheat and cause the white metal to run. Thereafter there would be much lamentation and cursing as engineers turn-to to fix it.
Normal lub oil pump discharge pressure as I remember was about 30psi.

Barry M

True oil is supplied to the bearings via a pump at all times, however, there is a separate circuit for jacking oil to create sufficient pressure to raise the turbine shaft from the bearing surface. The regular lube oil pump doesn't create sufficient pressure by itself to do the xjacking, but more in the way of volume to carry out continuous lubrication.

John

BarryM · « **Reply #58 on:** August 21, 2009, 02:04:51 pm »

John,

Having sailed with turbine plant from 12,000 to 32,000shp, I have never come across a turbine plant with separate 'jacking pumps'. The standard lube oil pumps were all that were needed to create the oil film and lift the shaft sufficient for starting. Once the shaft starts to revolve, it and pump pressure, create the oil wedge itself as its tries to climb the bearing wall.

What ship did you see the system on?

Barry M

oldiron · « **Reply #59 on:** August 21, 2009, 02:16:23 pm »

Quote from: BarryM on August 21, 2009, 02:04:51 pm

John,

Having sailed with turbine plant from 12,000 to 32,000shp, I have never come across a turbine plant with separate 'jacking pumps'. The standard lube oil pumps were all that were needed to create the oil film and lift the shaft sufficient for starting. Once the shaft starts to revolve, it and pump pressure, create the oil wedge itself as its tries to climb the bearing wall.

What ship did you see the system on?

Barry M

I've worked steam power plants for many years, from 300MW to 700MW units and they've all had separate jacking oil pumps.

John

BarryM · « **Reply #60 on:** August 21, 2009, 02:24:19 pm »

John,

Are you talking about marine plant?

Barry M

oldiron · « **Reply #61 on:** August 21, 2009, 02:31:33 pm »

Quote from: BarryM on August 21, 2009, 02:24:19 pm

John,

Are you talking about marine plant?

Barry M

Nope, stationary plant.

John

gondolier88 · « **Reply #62 on:** August 21, 2009, 06:26:21 pm »

Hi,

Heres a qoute on Titanic's machinery;

"Titanic's hungry furnaces consumed 825 tons of coal per day, generating 51,000 horse power. During normal operating speeds, Titanic's steam pressure was set to function at 215 psi. Reciprocating engine revolutions were 77 per minute and her turbine revolutions were 127 per minute. 14,000 gallons of drinking water [read pure water- evaporated probably-greg] were used each 24 hours."

Greg

dave301bounty · « **Reply #63 on:** August 21, 2009, 07:05:49 pm »

Great to see and read all this Steam ,from my experience ,the turning gear was the first thing to be engaged after F W E .then it was a case of the usual before a hammer test .Steam men will know all this .All i have from my days are a lot of memories ,but kept a drip feed lub cup ,and a fusible plug from a coal fired job .. But these photos that you are bringing out ,they are Brilliant and the memories flood back . Well done and thankyou .

gondolier88 · « **Reply #64 on:** August 21, 2009, 09:17:52 pm »

Hi Dave301,

What was the coal fired vessel you served on?

Greg

Steamer · « **Reply #65 on:** August 22, 2009, 03:21:12 am »

Sabino....as a volunteer engineer for 12 years....burned soft coal

Dave

oooops wrong Dave.....Sorry Dave301

gondolier88 · « **Reply #66 on:** August 22, 2009, 09:14:14 am »

Oh, I know about you Dave, I know ALL about you Dave.....

Greg

BarryM · « **Reply #67 on:** August 22, 2009, 03:25:58 pm »

Quote from: oldiron on August 21, 2009, 02:31:33 pm

Nope, stationary plant.

John

John,

Thought so; it's certainly not marine practice.

Cheers,

Barry M

Steamer · « **Reply #68 on:** November 11, 2009, 02:47:24 am »

Any word on Karl Rosyth?

Dave

ROSYTH · « **Reply #69 on:** November 11, 2009, 01:51:31 pm »

Hi folks, well I sent the letter off quite some time ago now but as of yet still not received a reply from the good man himself.
This could be down to his work level or build time or just old age!!!!

All i can do is wait really and hope we get a reply on what he is currently building and at what stage he is at with the other engine to match the one in display.

I will off course let all know when and if something drops through the door ok.

Some good stories and info been generated here on this piece of kit and steam in general so thanks, keep it going.

Cheers
R

Steamer · « **Reply #70 on:** November 13, 2009, 01:08:59 am »

Thanks Rosyth,

Well in the vain of keeping it going.......

Here' one I helped to restore......19.75 x 29.5 x 30 compound from the tugboat "Pegasus"

I'm the big guy with dark hair hanging on the reverse lever with both hands.........somebody in a time long ago "disabled" the throttle balance valve and if not careful would pick you up off the ground at 25 psi.

Dave

gondolier88 · « **Reply #71 on:** November 13, 2009, 08:08:16 am »

Lovely compound Steamer, what make is it? Looks very simillar to a Sissons, but they tended to be smaller than that? Did it go back into the tug?

Greg

Steamer · « **Reply #72 on:** November 14, 2009, 09:49:42 am »

IIRC it was made at Mare Island along with the tug. The HP piston and piston valve have no rings ( !) Just a good fit.

Not unlike some Stuarts I've seen....

Dave

gondolier88 · « **Reply #73 on:** November 14, 2009, 12:26:23 pm »

Quote from: Steamer on November 14, 2009, 09:49:42 am

IIRC it was made at Mare Island along with the tug. The HP piston and piston valve have no rings ( !) Just a good fit.

Not unlike some Stuarts I've seen....

Dave

Yes, your quite right about some ST engines not having rings, the D10 i'm building doesn't have any, however a slow revving compound is one thing, but a HP twin working upto 2000rpm is quite another thing, even if it is only 3/4" + 3/4" x 3/4", so i'm putting rings on my pistons.

Greg

Steamer · « **Reply #74 on:** November 14, 2009, 11:42:06 pm »

I suspect the purpose of not using rings on the tug engine was reliability. No ring issues...period.

If your hauling railroad car barges or petroleum in New York Harbor.....failure is not an option.

All the bearings where water cooled....including the crossheads.

She's about 750 BHP @ about 120 rpm. That puts the average piston speed at 600 feet/minute.

30/12 feet x 2/rev x 120 rpm= 600 feet /minute.

With a Stuart D10... your piston speed at 2000 rpm is 250 feet/minute.

.75/12 feet x 2/rev x 2000 rpm = 250 feet/minute

So the Tug piston is traveling on average more than twice as fast.......funny how math works

.

Dave

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Author Topic: Now this is a STEAM Plant something to aspire too.....what (Read 34535 times)

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