6-1. GENERAL
Operating experience is the basis for determining the need for machine overhaul with wheel and nozzle erosion and other wear being caused by carry-in of solids from the process, seal gas, and oil streams. Parts erosion or wear would be indicated by performance falloff, increased vibration, or increased seal gas consumption or vent flow. Regularly scheduled maintenance is not required. The following procedure describe plug-in cartridge disassembly and assembly. Numbers in brackets [ ] indicate item “reference designators” on the Turbo Assembly Drawing and the respective single level bill of material.
CAUTION
If any replacement hardware is used (for example, nuts, bolts, etc.), make certain that it is of equal or better quality than that called out in the bill of material. The following component weights and their respective center of gravity should be considered before any maintenance procedure.
| Plug-in Cartridge | 1,650 lb | (749 kg) |
| Expander Case | 995 lb | (452 kg) |
| Compressor Case | 1,900 lb | (864 kg) |
| Electric Actuator and Bracket | 120 lb | (55 kg) |
| Total Weight | 4,600 lb | (2090 kg) |
In addition to the following drawings, refer to the ETAC-8RG Turboexpander removal and installation instructions provided later in this section. Turbo Assembly Drawing
6-2. ETAC-8RG PLUG-IN CARTRIDGE DISASSEMBLY
NOTE
Disassembly is normally accomplished at the Company CryoMachinery Production Facility by trained mechanics. If field disassembly is performed, the following procedure should be used. Read all notes on the Turbo Assembly Drawing before beginning disassembly. The following instructions are not to be considered sufficient for an inexperienced mechanic.
| 1 | Remove nuts (58) holding the turboexpander shroud plate on and remove all washers (54 and 43). Remove expander shroud (15) and zero-clearance plate (18) and Omniseals (61, 62) being careful not to lose or damage them. |
| 2 | Insert the shaft locking screw into the speed probe hole in the shaft to keep the rotor assembly from rotating while the wheel bolt is removed. Warm the expander wheel uniformly with a blower heat gun until it can be removed from the shaft by hand (66°C [150°F] maximum allowable temperature). Use jacking bolt and a 0.375” diameter x 8.5” long pin in the wheel bolt hole to jack the wheel off the shaft.
CAUTION Do not force the wheel to remove it. Do not use a torch to heat the wheel, as this may cause localized hot spots, which can destroy the metallurgical properties of the wheel. |
| 3 | Remove the actuator lever (A3) by removing snap ring (84). |
| 4 | Remove the wire (53) and insulation (14). |
| 5 | Remove the capscrews (42) that attach the nozzle assembly (N) to the bearing case (12), and remove the nozzle assembly. NOTE The nozzle assembly should not be disassembled any further unless the vanes have been bent or severely eroded and parts replacement is necessary. Do not tip nozzle assembly, or the vanes may fall out. |
| 6 | Remove the capscrews (78) and washers (48 and 40) holding the expander seal (1) in place. Using the jacking screw holes, back the seal out evenly to remove the seal. |
| 7 | With the shaft locking screw still in place, remove the compressor wheel bolt. The wheel is equipped with jacking threads to facilitate removal. Use jacking bolt and a 0.375” diameter x 6” long pin in the wheel bolt hole to jack the wheel off the shaft. |
| 8 | Remove the compressor seal bolts (57) and compressor seal (6). Remove the compressor diffuser screws (47) and plate (22). |
| 9 | If the expander bearing has RTD wires, disconnect the RTD wire sealing fitting (39) and pull the wires through the bearing case passage toward the bearing. Remove capscrews (41) and expander bearing (3), being careful not to lose or damage the shim (8). Using a felt-tip pen, mark this shim “expander.” |
| 10 | Remove shaft through expander end of bearing case. |
| 11 | If the compressor bearing has RTD wires, disconnect the RTD wire sealing fitting (39) and pull the wires through the bearing case passage toward the bearing. Remove capscrews (41) and remove compressor bearing (5) and shim (8). Using a felt tip pen, mark this shim “compressor.” |
This completes disassembly.
6-3. ETAC-8RG PLUG-IN CARTRIDGE ASSEMBLY
NOTE
Assembly is normally accomplished at an Company shop by trained mechanics. If field assembly is preformed, the following procedure should be used. Read all notes on the Turbo Assembly Drawing before beginning assembly. The following instructions are NOT to be considered sufficient for an inexperienced mechanic.
CAUTION
If any replacement hardware is used (for example, nuts, bolts, etc.), make certain that it is of equal or better quality than that called out in the bill of material.
NOTE
Lightly coat all O-rings with a process-compatible grease.
CAUTION
Do NOT coat any of the spring-loaded seals with grease or lubricant. These seals must remain dry.
NOTE
When installing parts, snug all bolts, and then tighten to torque shown on the Turbo Assembly Drawing. Torque in a star-like pattern to prevent distortion of the assembly.
NOTE
All axial clearances are to be checked with the rotor thrust to the expander, since this is the way the machine will run under design conditions. Be certain to follow listed torque values on the above drawing during assembly.
PREASSEMBLY
| 1 | Clean and inspect parts. Replace all O-rings and gaskets removed from the machine as well as any seals which are worn or damaged. |
| 2 | Check and record bearing, shaft, drive collar, wheel, and seal diameters before assembly so that clearances N, O, R, T, V1, V2, V3 and W1, W2, W3 can be checked. These clearances are not adjustable, and can be changed only by changing bearings, seals, wheels, or shrouds. |
| 1 |
Install the compressor bearing (5) and full shim pack (8) or existing compressor bearing shim into the bearing case and secure with capscrews (41). |
| 2 | Slide the shaft (short end first) from the expander end through the bearing until it stops. |
| 3 | While holding the long end of the shaft, slide the full shim (8) and expander bearing
(3) over the shaft and attach them to the bearing case. If the plug-in cartridge is being reassembled, reuse shims marked “expander” and “compressor.” |
ASSEMBLY
| 4 | Install the nozzle assembly (N) onto the bearing case and check clearance Y as instructed in steps 7–9. Do not install the expander seal (1) until the bearing shims
have been set. |
| 5 | Install the shaft locking screw to prevent the rotor from rotating. Warm the expander wheel uniformly with a blower heat gun until it can be installed onto the drive collar by hand (66°C [150°F] maximum allowable temperature).
CAUTION Do not force the wheel to install it. Do not use a torch to heat the wheel, as this may cause localized hot spots which can destroy the metallurgical properties of the wheel. |
| 6 | Draw expander wheel onto the shaft using the wheel screw and the spring washer. Torque expander wheel bolt to the value provided on the Turbo Assembly Drawing. |
| 7 | Adjust the shim behind the expander bearing (3) to set axial clearance Y. The rotor must be thrust toward the expander to set the shim. Using a wooden block, apply force on the compressor wheel bolt to thrust the rotor assembly toward the expander end. The wheel will need to be installed and removed if any adjustments to the expander bearing shim (8) are required. Use the shaft locking screw to prevent the
rotor from turning when installing or removing wheels. Record final clearance Y. |
| 8 | Shim the compressor bearing (5) to adjust the axial thrust float, clearance M, and check with a dial indicator. Record clearance. |
| 9 | After both bearings have been shimmed, remove the expander wheel and nozzle assembly (N). If the expander bearing has RTD leads for the journal and thrust pads, these leads are fitted through connection X in the bearing case. The leads pass through a Conax connector (39) which also seals. The unused passages in the Conax connector (39) should already be plugged with extra bearing RTD wire. |
| 10 | Install the compressor seal (6) and diffuser plate (22). |
| 11 | Install shaft locking screw to prevent rotor from rotating. Assemble the compressor wheel onto the shaft. Draw the wheel onto the shaft using the compressor wheel bolt. Torque the compressor wheel bolt to the value provided on the Turbo Assembly Drawing. |
| 12 | Measure and record clearance X to ensure it is within the required range (this clearance cannot be adjusted). |
| 13 | Install expander seal (1) and gasket (2) using Permatex. |
| 14 | Install nozzle assembly (N) and O-ring (73). Make sure nozzle vanes are installed properly on the pins. |
| 15 | Install insulation (14) and wire (53). |
| 16 | Warm the expander wheel with a blower heat gun until it can be installed onto the shaft by hand (66°C [150°F] maximum allowable temperature).
CAUTION Do not force the wheel to install it. Do not use a torch to heat the wheel, as this may cause localized hot spots which can destroy the metallurgical properties of the wheel. |
| 17 | Draw expander wheel into the shaft using wheel screw and spring washer. Torque expander wheel bolt to the value provided on the Turbo Assembly Drawing. |
| 18 | Remove shaft locking screw. |
| 19 | Install zero-clearance plate Omni seals (61, 62, 75) and shroud onto vanes and bolt up tight. |
| 20 | Using a wooden block, apply force on the compressor wheel bolt to thrust the rotor assembly in the expander direction. Using a dial indicator, make sure axial thrust float M still exists. Set shim (20) to achieve clearance P per Clearance Notes on the Turbo Assembly Drawing. Plug-in cartridge is now ready for installation as instructed in 5-3. |