There are many critical bolting applications on reciprocating compressors, and the Nord-Lock Group has extensive experience meeting these challenges.
One particular application, the crosshead jamnut, is well known for the difficult and unsafe bolting methods used to attempt to tighten it. Common methods include using sledgehammers and overhead cranes. As an example, one petrochemical company employee had his jaw broken and facial damage when the wrench he had hit with a sledgehammer slipped and hit him. Other common occurrences include hand, arm, and back injuries.
The large sizes of piston rods make it especially difficult to obtain proper tightness. Since tightening the crosshead nut requires going through an inspection door there is little room to maneuver.
Superbolt multi-jackbolt tensioners from Nord-Lock make the installation of piston rods easy. Thousands of crosshead jamnuts have been used in the field. The torque on the individual jackbolts is applied with only a hand held torque wrench to achieve a high preload. This eliminates the dangerous and inaccurate bolting methods commonly used.
Ease of use and reliability have led to many customers outfitting all their critical reciprocating compressor bolting components with multi-jackbolt tensioners.