Coupling Sleeving/Bolt Retrofits

Coupling Sleeving/Bolt Retrofits

Coupling Hole Sleeving

As turbine rotors get older and are swapped in and out of different units the hole sizes become large and it becomes necessary to bring them back to nominal.Having sleeved a countless number coupling holes BFW has the experience and equipment to rapidly bore and sleeve the coupling holes back to the nominal size.

Bolt Retrofits

Eliminate bolt seizure, coupling slippage and concentricity battles...

Hydraulic Coupling Bolts have long been recognized for their ability to overcome the inherent problems of standard coupling bolt designs. They are being used throughout the world in many diverse applications of large-shaft couplings. From Steam Turbines in Power Generation Plants to Propulsion Shafts in the Marine Industry to Large Motor Transmission Couplings in the Steel and Paper Industries, these bolts are proven in their ability to reduce critical equipment downtime and enhance machine reliability.

Hole Requirements

Hydraulic coupling bolts were developed to overcome the shortfalls of their traditional predecessors. Their design and operating characteristics prevent coupling bolt binding, coupling hole damage and coupling slippage. Furthermore, their use ensures rapid and predictable coupling assembly and disassembly times. It is for these reasons that these kind of coupling bolts are becoming the preferred technology choice for both new and existing large couplings.

In order to derive the fullest benefits of these bolts, it is important to understand the mechanical actions of an expanding sleeve in a coupling hole: During actuation, the sleeve expands uniformly along its length. If the sleeve encounters a bore discrepancy during expansion, it may react from such a point thus disturbing the concentricity of the two associated coupling halves. This could lead to a time-consuming requirement of having to re-establish concentricity before other bolts are installed. In some cases, concentricity is not affected but, full contact of the sleeves in the coupling bores is not achieved. In this event, a future system fault may cause coupling slippage and consequential shaft vibration.

Traditional methods such as honing, reaming or even boring with non-specific equipment cannot achieve the tight tolerances of cylindricity recommended for the best operation of this type of bolt. In response to this problem, the BFW technology and methodology was developed in the early 1990's with the explicit goal of producing the most exacting hole tolerances with the least impact to the Critical Path.

Contact us today to discuss how we can provide you with the assurance of obtaining the best possible return from your coupling bolt investment.