RHM Series, Hydraulic Nut

Series: RHM | Product Line: Industrial Tools

Precision Pre-Tensioning & Friction-Free Operation: The RHM converts hydraulic pressure directly into axial preload, eliminating the friction variables and side-loading inherent in traditional torque methods. An integrated high-pressure oil cavity and piston structure generate pure axial force that produces precise elastic bolt elongation. Preload force is determined solely by hydraulic pressure (F = P × A), removing torque coefficient uncertainty and delivering accuracy of approximately ±5%—far exceeding the ±25–30% typical of torque-controlled methods.

Mechanical Load Holding with Lock Ring: Once the target preload is achieved, the lock ring on the outer circumference is manually rotated to secure the axial load mechanically. After hydraulic pressure is released, the preload is retained entirely by the lock ring—no continuous pressurization is required, and the hydraulic system bears no residual load. The hydraulic nut remains permanently installed on the bolted connection.

Compact & Reliable Construction: Manufactured from high-strength alloy steel with precision machining and heat treatment, the RHM delivers exceptional load capacity, fatigue resistance, and long service life. A corrosion-resistant coating provides protection in harsh industrial environments. A robust piston guide bushing ensures stable operation, while the preload does not require cylinder pressure to be maintained.

No Thread Projection Required: Unlike bolt tensioners that require sufficient thread overhang for engagement, hydraulic nuts can be threaded directly onto bolts with limited thread projection. This makes the RHM particularly valuable for retrofitting older constructions where conventional torque wrench bolted connections can be replaced without modification.

Efficient Operation & Component Protection: The RHM generates pure axial tension without any rotational movement on the workpiece surface, eliminating surface damage and wear associated with torque wrenches and hydraulic torque tools—including the heavy reaction forces that can exert tens of tons of force on surrounding components. The tool remains easily removable and reusable even after years of service, facilitating future maintenance and inspection.

Substantial Time Savings: For multi-bolt applications requiring high preload forces, RIVERLAKE hydraulic nuts can reduce tensioning time by up to 99% compared to conventional methods, with the greatest efficiency gains realized on large thread diameters and high-force requirements.

Synchronized Tensioning Capability: When multiple RHM hydraulic nuts are used simultaneously, each bolt receives exactly the same preload force—not just the same elongation distance. This enables uniform clamping force distribution, eliminates gap variations between components, and enhances flange sealing performance for critical joints such as pressure vessels and pipeline connections.