Sundyne LMC 341F, Instruction And Operation Manual

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5s.
When the impeller is completely cooled, remove the impeller bolt (3) and the soft metal washer
and then reinstall the impeller bolt, without the soft metal washer and torque per Table 8.1.
5t.
Record the thickness of the impeller spacer (158C) and the impeller shroud to diffuser cover
alignment (Dimension “E” in Figure 5.1) for future reference.
Impeller/Diffuser Clearance Calculation
The clearance between the impeller and diffuser must be checked and, if necessary, adjusted after
the replacement of any of the following parts: gearbox assembly, gearbox high speed shaft (A130),
gearbox high speed shaft bearings (151A or B), diffuser (13), impeller (2), compressor casing (1),
seal housing (30).
Step 1
The required impeller to diffuser clearance is 0.035 - 0.055 inches, see (“A”) dimension in
(Figure 5.1) . This clearance is obtained by installing shim spacers (158A) between the diffuser and
compressor casing, see (“B”) dimension in the (Figure 5.1). The recommended procedure for
determining shim spacer requirements is as follows:
Step 2
Refer to (Figure 5.1). The seals, seal housing, diffuser cover, and impeller must be installed on the
gearbox. The diffuser must be bolted into the compressor case (1).
Step 3
Using electrical solder, make a ring that is slightly smaller in diameter than the impeller blade
diameter. Place the solder ring on the diffuser and center it around the inlet eye. Use tape to hold the
solder in place.
Step 4
Install the complete compressor assembly and gearbox in to the compressor case and tighten four
equally spaced seal housing nuts (914A) onto the case studs. Use the proper torque given in Table
8.1. Then remove the seal housing nuts and carefully lift out the compressor assembly from the
compressor case.
Step 5
Measure the thickness of the solder ring at points where it contacted the impeller blades and record
the average thickness. This is the “A” dimension in
(Figure 5.1). This impeller to diffuser clearance
must be between 0.035 and 0.055 inch (0.089 and 0.140 mm).
Step 6
If the impeller clearance is not within the proper range, calculate the required change in shims. Add
or remove diffuser spacers (158A) to adjust the clearance to the correct range.