Impeller Maintenance
This section of the manual provides a comprehensive guide on Impeller maintenance. It covers safety precautions, the tools and materials needed, detailed procedures for thruster change-outs and cleaning and inspection guidelines. By following these guidelines, operators can ensure Hydrus continues to perform at its best in all underwater operations.
Thruster Assembly Exploded
Thruster Assembly Exploded
Thruster Layout
Clockwise (CW) Rotor
The CW Rotor can be denoted by a white ribbon around it's surface and the base of the rotor blade inclines towards the left.
Note: The CW Impeller can be inserted into the thruster guard either way up (white line up or down), there is no significance.
CW Top View Side View
Counter Clockwise (CCW) Rotor
The CCW Rotor can be denoted by no ribbon on the surface of the rotor and the rotor blade base leans outwards towards the right.
Note: The CCW Impeller can be inserted into the thruster guard either way up, there is no significance.
CCW Top View Side View
Thruster Layout Complete
Thruster Layout Complete
| Thruster Number | Rotor Direction | Guard Type |
|---|---|---|
| 0 | Counter Clockwise (CCW) | Horizontal Guard |
| 1 | Clockwise (CW) | Horizontal Guard |
| 2 | Counter Clockwise (CCW) | Horizontal Guard |
| 3 | Clockwise (CW) | Horizontal Guard |
| 4 |
Clockwise (CW) |
Vertical Guard |
| 5 |
Counter Clockwise (CCW) |
Vertical Guard |
| 6 | Counter Clockwise (CCW) | Vertical Guard |
Horizontal Thruster Guard
The Horizontal Thruster Guard is a protective component designed to prevent damage to the thrusters of the Hydrus. The Horizontal Thruster Guard is characterised by a curvature of the base of the guard that aligns with the main body of Hydrus, the guard will house in the shallow cassette on the Hydrus which is depicted in the illustration below.
Horizontal Thruster Guard
Vertical Thruster Guard
The Vertical Thruster Guard's design is distinct from the Horizontal Thruster Guard. While the Horizontal Thruster Guard is characterised by a curvature that aligns with the main body of Hydrus, the Vertical Thruster Guard has a base that is near straight and will sit in the deeper cassette on the Hydrus main body. see below for illustration.
Hydrus Flat Surface
Ceramic Bearings
The ceramic bearing is a disc-shaped assembly composed of a hollow ceramic ring. This ring includes an inner and outer raceway that encapsulates extremely hard and smooth ceramic balls. Each thruster assembly requires two of these ceramic bearings. They are positioned on either side of the rotor and are fit between the thruster guard and the thruster cassette.
Ceramic Bearing
Tools and Materials Needed
| Item | Quantity |
|---|---|
| 2.5mm Hex Head | 1 |
| Horizontal / Vertical Guard | 1 |
| Clockwise (CW) / Counterclockwise (CCW) Rotor | 1 |
| M4 x 12mm Bolts | 4 |
| Hydrus Thruster Bearing, Ceramic | 2 |
Thruster Guard Removal: Using the 2.5mm hex key, carefully unscrew the four M4 x 12mm Ti thruster guard screws. Keep these screws in a safe place for reassembly.
Hydrus Vertical Thruster Removal
Thruster Removal: Gently detach the thruster guard from the main body of the Hydrus. This should require minimal force. The rotor and the ceramic bearing are housed within the thruster guard.
Thruster removal
Component Separation: Separate the rotor and the ceramic bearing located inside the thruster guard. Further dismantle the two ceramic bearings from the rotor by gently pulling around the collar of the bearing
Rotor Assembly Separated
Note: Thoroughly inspect the thruster guard, the two ceramic bearings, thruster guard and the rotor for any signs of damage. Replace any components as necessary.
Note: It's crucial to handle ceramic bearings with care, as dropping them could result in damage, potentially rendering them unusable.
Note: Exercise caution to avoid applying any pressure on the impeller blades while extracting the bearings.
Rotor Identification: Determine whether the rotor being replaced is a CW (Clockwise Rotor) or a CCW (Counter Clockwise Rotor).
Rotor Identification
Reassembly: Reattach the two ceramic bearings to the rotor and slide the assembly back into the thruster guard.
Thruster Re Assembly
Thruster Replacement: Carefully align and reattach the thruster guard to the main body of the Hydrus. Ensure that the thruster assembly is properly seated in the cassette. Insert and hand-tighten the thruster guard screws. By hand, test spin the newly mounted thruster assembly to ensure smooth and free rotation. If required, adjust tension on the mounting bolts to ensure on cross-torque is being applied to the guard that may prevent the Impeller from spinning.
Note: Adjust the torque on the mounting bolts as needed to prevent the force on the guard from obstructing the impeller's spin.
Thruster Replacement
Hydrus Complete
Note: Self-Test: After the thruster has been replaced and secured, conduct a Testing and Functional Checks to ensure the new thruster is functioning correctly.