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EM 5540 December 28, 1999 Page 1
Gas Turbine Aft Support Legs Drop Check
INTRODUCTION This article details specific instructions for performing a drop check on a gas turbine's aft support legs as required by Basic Field Alignment Instruction ML 0411. The gas turbine is supported by a shipping pin at its aft casing to secure its weight and avoid distortion of its support legs due to potential lateral movements during shipping. After the gas turbine contact check and rough alignments are completed and turbine is fixed to its foundation, the shipping pin must be removed per ML 0411. Upon removal of the shipping pin, the gas turbine aft support legs are to set onto leg shims, and a drop check must be performed to ensure that no distortion of the base has occurred during transport or jacking during contact checks. HEALTH AND SAFETY REQUIREMENTS In all cases, the Health, Safety and Environmental Manual (HSEM) will be the document followed on the job site during performance of this procedure. Safety, health and environmental protection must be an integral part of all department business operations, including design, construction and start-up. Every reasonable effort will be made to create and maintain a safe and healthful work environment at each customer site. REFERENCE DOCUMENTS No.
Description
ML 0410 ML 0411
Instructions, Alignment – Factory Instructions, Alignment – Field Basic
REQUIRED TOOLS AND EQUIPMENT •
140 Ton Hydraulic Jack with minimum 2 inch travel
•
Three (3) Dial Indicators
•
Base Plate – 3/8 in. x 5.0 in. x 5.0 in.
•
Spacer
•
Ball with 1 inch diameter
•
All Components are to be fabricated from Carbon Steel.
Issued by: Energy Services – Methods
Scheduled Review: November 2001 GE Energy Services
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Gas Turbine Service Manual Subject
Gas Turbine Aft Support Legs Drop Check
EM 5540 December 28, 1999 Page 2
DROP CHECK PROCEDURE 1.
Clean and measure the gas turbine leg shims as supplied. Do not mix shims from different legs together.
2.
Use the carbon steel plate as a base plate for the 140 ton hydraulic jack.
Note:
If a 12 inch, 140 ton hydraulic jack with a minimum 2 inch travel is not available, a 140 ton jack with a different height may be used if the difference in height can be adjusted with a spacer.
3.
Place the jack on the base plate.
4.
Place the spacer with the ball on the hydraulic jack.
5.
Raise the jack, ensuring that the ball enters the recess in the casing fabricated by GE.
Note:
Ensure that the cooling water piping to the gas turbine legs is removed. For dual or liquid fuel units, ensure that the atomizing air pre-cooler cooling water piping is disconnected.
6.
Apply penetrating oil to the shipping pin to facilitate smooth removal. Remove the four (4) bolts holding each turbine leg to the turbine base. Clean and remove any paint or burrs that may exist between the bottom of the turbine leg and its base support pad.
7.
Place one dial indicator to indicate on the bottom dead center of the casing. Use the jack to raise the turbine approximately 1 to 3 mils, and remove the shipping pin with a drift pin and a sledge hammer. Install the turbine leg shims in their respective locations, and lower the turbine down onto the shims.
8.
Set the remaining two dial indicators at zero and place them on the aft turbine support legs.
9.
Lift the casing to 0.1 mm as determined by the dial indicator that reads first.
10.
Record dial indicator readings on each aft turbine support leg.
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Gas Turbine Service Manual Subject
Gas Turbine Aft Support Legs Drop Check
EM 5540 December 28, 1999 Page 3
11.
Repeat Steps 9 and 10 at 0.1 mm increments up to a height of 0.5 mm. Perform this procedure twice at each 0.1 mm increment to ensure accuracy. The maximum allowable difference between each reading is 0.38 mm.
12.
If the difference in readings of the two legs is within tolerance and repeatable, then the drop check is completed. If the difference in readings of the two legs is out of tolerance (as specified in ML 0411), perform the procedure specified in ML 0411 to correct the deficiency.
13.
Dowel the turbine support legs to the I-Beam base, and torque the hold down bolts to their proper torque values. Replace the gaskets on the cooling water supply piping and tighten the flanges. Set and lock the turbine gib locating bolts at 0.001 inch and 0.003 inch as specified in ML 0411.
FIELD PHOTOS The following reference photographs were taken in the field during the installation phase.
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Gas Turbine Aft Support Legs Drop Check
EM 5540 December 28, 1999 Page 4
Figure 1. MS6001B Gas Turbine on 3-Point with Running Shim Pack Taped to Aft Leg
Figure 2. MS6001B Gas Turbine Shim Pack being Cleaned and Mic-ed
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Gas Turbine Aft Support Legs Drop Check
EM 5540 December 28, 1999 Page 5
Figure 3. MS6001B Gas Turbine Aft Gib Block with Shipping Pin Assembled
Figure 4. Removing Shipping Pin from MS6001B with Turbine Jacked Up 0.020 Inch
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Gas Turbine Aft Support Legs Drop Check
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Figure 5. MS6001B Gas Turbine on Jack with Shipping Pin Removed
Figure 6. Taking Drop Check Using Feeler Gauge
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Gas Turbine Aft Support Legs Drop Check
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Figure 7. Preparing to Remove Shipping Pin from MS6001FA with Turbine Jacked Up
Figure 8. Removing Shipping Pin from MS6001FA Gas Turbine
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Gas Turbine Aft Support Legs Drop Check
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Figure 9. Preparing to Take Drop Check Using Feeler Gauge with MS6001FA Turbine Jacked Up and Shipping Pin Removed
Figure 10. MS6001FA Gas Turbine with Running Shims Assembled
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