API STD 671 Compliance for Hydraulic Clamp Hub
March 8th, 2021
Riverhawk Company, a leader in engineered tooling and solutions for turbomachinery and rotating equipment, is proud to announce that its Hydraulic Clamp Hub is now an accepted alternative to traditional shaft-end connections as defined in the 5th edition of the American Petroleum Institute Standard 671 (API STD 671).
API STD 671 outlines requirements for high-performance couplings used in power transmission between rotating shafts in critical applications within the petroleum, petrochemical, and natural gas industries.
A Proven Solution for Shaft-End Connections
The Hydraulic Clamp Hub, a legacy product from Riverhawk, has long been used to replace traditional hubs in various applications, including generators, pumps, and refrigeration systems. This innovative design uses a hydraulic clamping force on the hub, offering a simpler installation process and cost-effective performance improvements.
Compared to conventional hydraulic hubs, the Hydraulic Clamp Hub provides key advantages.
Simplified Installation: Reduces labor time and complexity.
Cost-Effectiveness: Saves on total project costs.
Improved Durability: Eliminates tissue-like galled shafts.
Enhanced Performance: Enables the use of smaller diameter shafts while maintaining the same torque capacity, reducing the overall overhung moment.
How The Hydraulic Clamp Hub Works
The Hydraulic Clamp Hub operates by using hydraulic pressure to generate a clamping force that securely grips the hub to the shaft. This design eliminates the need for keyed or splined mounting, replacing traditional dilation and pull-up methods. The result is a robust, interference-fit connection that complies with API STD 671 requirements for torque transmission and balance.
Alignment with API STD 671
The 5th edition of the API STD 671 introduces a provision for alternative hub designs in Section 8.6.4, titled ‘Alternate Hub Design’. This section states:
“Alternative coupling-to-shaft juncture methods (providing an interference fit) other than keyed or hydraulically fitted hubs may be proposed as an alternative, as determined by the purchaser, provided such methods comply with all the requirements of this document including but not limited to torque transmission and balance requirements. Any exceptions shall be approved by the purchaser.”
“The Hydraulic Clamp Hub has always been a reliable alternative for shaft-end connections,” said Pat McCormack, Mechanical Engineer and Director of Business Development at Riverhawk Company. “With its inclusion in the latest edition of API-671, or clamped shaft-end technology is now accessible to more users in the petroleum, petrochemical, and natural gas industries who demand high-performance couplings.”
Growing Adoption of Clamped Shaft-End Technology
Clamped shaft-end connections are gaining popularity among end users and Original Equipment Manufacturers (OEMs) due to their ability to address common issues with traditional hub designs. By offering superior performance and ease of installation, the Hydraulic Clamp Hub continues to set a new standard for rotating equipment solutions.
About Riverhawk Company
Riverhawk Company has over 30 years of experience as a leading manufacturer and engineering design firm serving the petroleum and power generation industries. Its product portfolio includes hydraulic tensioners, powertrain couplings, and instrumentation, along with comprehensive maintenance, repair, and training services for turbomachinery and rotating equipment.
To learn more about the Hydraulic Clamp Hub or Riverhawk’s solutions, visit www.Riverhawk.com.
