vertical turbine vs horizontal

7/27/2019 Vertical Turbine vs Horizontal

http://slidepdf.com/reader/full/vertical-turbine-vs-horizontal 1/5

Which is better, vertical or horizontal position when stress relieving turbine rotors.

After rebuilding (welding) turbine rotor, it is necessary to stress relief them, which is better to do it

in a vertical or harizontal position.

8 days ago

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Guadalupe Capetillo, Rashid Mahmood like this

17 comments

Amitabh Srivastava

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Amitabh Srivastava • For stress relieving and thermal stabilization of the rotor it is to be rotated at 3-4 RPM continuously. For this reason it is always better to have rotor in horizontal position unless size

of the rotor is very small for handling it it vertical position. All large steam turbine rotors are stress

relieved anf thermally stabilized in horizontal position.

8 days ago• Like1

Frans de Graaf

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Frans de Graaf • the stress relief will have to be done in a contoled environement and as mrSrivastava explained with slow rotation this is the most common in a horizontal position

8 days ago• Like

Hasan Helali

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Hasan Helali • Sure vertically

8 days ago• Like

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Danny Ciarlariello • We have performed hundreds of heat treatments of turbine rotors with the

majority being

done in the horizontal and continually rotated uni directionally.

8 days ago• Like

Einar Valmundsson



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Einar Valmundsson • But why do it in a horizontal possision, as I see it, the + are more on the

horicontal method.

Info: I´m doing the machining and welding on a special mobile lathe.

Vertical:

+ Less change of deformasion due to graviti of earth

+ Rotor is static so less work to preper covers and heat around the rotor. (you can put it on the rotor

instead of having a clearans betwen so the rotor can rotate)

- You can not instal the cover from ground level.

Horicontal:

+ You can instal covers from ground level

- You will perhaps have to replace the bearing support holding the rotor from Babbit bearing to

normal ball bearing witch can tolerate the heat

- I have more change of deforming my lathe when heating the rotor there in horicontal

7 days ago• Like

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Danny Ciarlariello • We do the preheating and stress reliving using specialized Induction heating

units,

whereas the rotor turns inside of a fixed coil. Allowances have to be made for thermal expansion and

contingency's to allow constant rotation. (The rotor cannot be allowed to stop rotating once the

process has begun). For PWHT of larger areas or straightening

we will build a heat lathe. For either method, (Welding/preheating or PWHT) the rotor must be out

of the unit, in a lathe or other suitable turning device.

FYI; Most of our applications are proprietary in nature and we can only provide general information

about this process.

7 days ago• Like

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Bill Kashin • I am an onsite provider of heat treating services and have performed stress relief in

both positions. One Turbo Machinery company that I provide for has written their procedure to hang

the rotors after weld repair. For this company we use ceramic heating elements that we attach

directly to the rotor.

If the entire rotor needs straightened, if the repair is to a disc area, or if the customer wants to keep

the rotor turning during the heat treatment, we use an induction coil suspended around the rotor.

Temperature measurements are taken using capacitance welded thermocouples and the

temperature readings are transmitted using a radio frequency to a laptop computer and stored as an

excel spreadsheet.

We have also built panelized furnaces around rotors using high voltage heaters to heat the furnace.

5 days ago• Like

Jeff Weinacker

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Jeff Weinacker • There was a time when many of us worked for one great company who did all this

work and provided the thermal engineering to support these customers who then took our

engineering and created their own specs.

I am still around, doing that same engineering work. Unfortunately the company many of us workedfor has been dismantled.

That being said, horizontal is better unless the customer does not have the required tailstock on

their Lathe. Better because there is less movement of the rotor, heat it in place. and if there is a

bow, the added weight of the rotor exerts a bit more force the "straighten" the shaft. But if the

equipment is not available, hanging it is the only method left.

The heat really does not care, its the steel in the rotor and the forces its subjected to that dictate

what method is used.

5 days ago• Like

Guadalupe Capetillo

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Guadalupe Capetillo • Hi Einar, I've found this link:

https://www.aegislink.com/presentations/2013_eums/pdfs/12_generator_rotor_welding.pdf

As I've been investigating both options are correct, but many factors can intervene to choose one orother option: equipment availability, damaged area, damage grade, etc...



But note that it's important that the rotor never stop rotating in horizontal position in order to avoid

deformations, so bearings supports must be able to support high temperatures.

3 days ago• Like3

Jeff Weinacker

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Jeff Weinacker • That's cool! it even shows one of the induction machines I built!

2 days ago• Like

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Bill Kashin • Excellent link Guadalupe! Very interesting presentation.

I was involved with one of the first rotating induction heat treatments at Turbocare in Texas, which

is where a couple of those photos look like they were taken.

Yes Jeff I see the old Mannings machine that you built. They are a versatile piece of equipment.

Can anyone in the group explain to me the slide near the end that is titled "Yoke over Rotor during

straightening". It looks like the rotor is stationary in the horizontal position. I am guessing that the

rotor has been placed with the bow at either top or bottom and the "Yoke" will apply a force to the

rotor after a certain when the temperature reached to "push" out the bow?

2 days ago• Like

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Danny Ciarlariello • Very good and informative presentation

2 days ago• Like

Guadalupe Capetillo

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Guadalupe Capetillo • Dear Bill, thank you! In reference to your question, I'm not a technician and

maybe my comment has not sense, but this is my appreciation: as the rotor is not rotating, could be

posible that the yoke acts as support or (as you say) apply force in order to not have deformations

during straightening?



I'll really appreciate your points of view, I'm a sales person but interested in learn technical

assesstments to improve my knowledges.

2 days ago• Like

Jeff Weinacker

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Jeff Weinacker • Bill, I see 60Cy Induction Equipment (yes 60Cy) in 2 photos where the Rotor is not

turning. Both are relatively small rotors. It certainly appears to be a "yoke" holding the rotor down. I

would personally be concerned about that method, however, its a way to apply force, that being

said, it must work.

1 day ago• Like

John Mitchell

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John Mitchell • Very good discussion and Guadalupe found a great presentation. Thanks.

It looks like the "yoke" is somehow supporting the rotor, near the middle, either to keep it from

sagging or physically straightening it, when hot enough. Would love to know more.

1 day ago• Like

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Bill Kashin • In looking at the yoke picture again I think that the yoke is applying a downward

clamping force. At the bottom of the yoke you can see nuts attached to the rods thru the cross

member. It's only a guess but since the picture is titled "straightening" they may have the bow at top

(to have gravity help), and apply a downward clamping pressure. Then provide a stress relief and

hope that the rotor relaxes.

Sound like a plan?

1 day ago• Like• Reply privately• Flag as inappropriate

John Mitchell

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John Mitchell • I have been corrected. There are rods on both sides of the I-beam and probably a

yoke over the rotor to pull it down, not hold it up.

It's hard to think of this process as being very accurate; however, I have no background beyondmeasuring runout and shipping rotors for rework.

vertical turbine vs horizontal

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