The Riverhawk Hydraulic Crosshead Nut is a hydraulic nut designed for long-service life.  A hydraulic nut provides a quick, efficient method of producing and retaining high clamping forces (preload) in the crosshead joint.  This is accomplished by connecting a hose from a high-pressure pump kit to the port in the hydraulic nut piston.  The pressurized oil fills the annular area inside the hydraulic nut, generating a large, purely axial load in the piston rod.  This load stretches the piston rod which creates a gap between the cylinder and retainer.  A wrench is provided to tighten down the retaining collar against the cylinder.  Once the hydraulic pressure or pressurized oil is released, the load is held back by the hydraulic nut.

A common question we often receive is, where is a Crosshead Nut used?  The Riverhawk Hydraulic Crosshead Nut is used on reciprocating compressors for petroleum chemical and gas industries.  The crosshead nut gets its name from the location it is used within the reciprocating compressor.  This is located on the crosshead slide.  The hydraulic crosshead nut connects the crosshead slide, which connects to the piston rod.  This is a very challenging joint to tighten due to space limitations.

Riverhawk Nut Detail

Customer Benefits

  • Significantly reduce installation and removal times.
  • Increased preload accuracy and repeatability- allows OEM’s to potentially uprate their machine providing better efficiency.
  • Reduced likelihood of piston rod failures.
  • Uniform, pure tension loading eliminates bending and twisting moments that can be induced into the piston rod by traditional torque methods.
  • No additional bending loads in piston rod due to off axis nut loading.
  • Reduces the likelihood of fretting between the bottom of the nut and crosshead face.
  • Eliminates high pressure sliding surface on threads of piston rods, extending rod life.
  • Improved operator safety- eliminates slugging wrench so no more hammers or cranes.
  • Hydraulic nut is optimized for alternating loads with high safety factor against fatigue failures.
  • Counter-weighted crosshead nuts are custom designed to match the weight of existing nuts and/or counterweights (used for balance).

Eric Rhymestine

Eric Rhymestine is an Inside Sales Manager at Riverhawk Company and has been with our organization since 2012. Eric holds a Bachelor’s of Business Administration and Management degree from St. John Fisher College.

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