FAQ - Hydraulic Hardware (Tensioning Nuts, Bolts Studs) And More… |
Hydraulic Tensioning
Q) Why would somebody tension a bolt instead of torquing it?
Q) How come tensioning is more accurate than torquing?
Q) Is tensioning really faster than torquing?
Q) Why would I use a Riverhawk Hydraulic Rod Tensioner (HRT) instead of other types of tensioners?
Q) Why are Riverhawk Hydraulic nuts designed with metal seals?
Q) Oil is a problem for me. Can Riverhawk sell me a system that uses a fluid that I can use?
Q) Can Riverhawk Hydraulic nuts be used in high temperature applications?
Q) Can Riverhawk design fasteners for high vibration environments?
Hydraulic Torque Coupling
Q) Why would I want to choose a Riverhawk Hydraulic Torque Coupler over a mechanical clamp?
Q) Can I use a Riverhawk HTC to mount a hub on a tapered shaft?
Q) Can I use an HTC as part of a field repair of a damaged shaft end?
Q) Can I use a Riverhawk HTC to salvage a hydraulic shaft end?
Q) Can I hse a Riverhawk HTC on a keyed shaft end?
VRD
Q) Why is the Riverhawk Viscous Rotational Damper better than rubber couplings?
Q) Can a Riverhawk Viscous Rotational Damper be tuned to specifically dampen my machinery vibrations? |
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Hydraulic Tensioning
Q) Why would somebody tension a bolt instead of torquing it?
A) While torquing is more familiar to most people, it does not provide an accurate and predictable squeeze. Tensioning will provide a much more predictable amount of squeeze. Also, human ability to turn a wrench is limited, so larger bolts and nuts require some powered method of tightening in order to generate the needed loads quickly.
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Q) How come tensioning is more accurate than torquing?
A ) Torquing requires that the torque be converted to load in the thread. This is very dependant on the surface condition of the threads and flange faces. It is well documented that threads change during tightening and that those changes are impossible to predict accurately. Tensioning is also independent of friction and the need for lubrication requirements as with torquing. Tensioning is a far more direct way of loading a fastener. It is fairly easy to measure the load produced by a load cell accurately.
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Q) Is tensioning really faster than torquing?
A) Tensioning is well suited to quick tightening of large fasteners. First, a tensioner generates full load in just a few seconds. Think about it, a tensioner is mainly a special hydraulic cylinder, similar to those in earth movers, elevators and machine tools. Those cylinders are relatively fast, so are tensioners. In addition, tensioners are well suited to simultaneous loading. This is a huge advantage in terms of time and even flange loading. (link)
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Q) Why would I use a Riverhawk Hydraulic Rod Tensioner (HRT) instead of other types of tensioners?
A) The Riverhawk HRT is specifically designed to operate in tight spaces. Other tensioning methods require a "foot print" around the nut to push against and require a relatively large amount of space over the nut for the load cell. The Riverhawk HRT requires NO foot print, has a very compact load cell and does not require extra stud thread to pull on. Great for retrofitting.
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Q) Why are Riverhawk Hydraulic nuts designed with metal seals?
A) Metal seals do not degrade over time like rubber ones do. Metal seals are far less sensitive to high temperature than elastomeric ones.
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Q) Oil is a problem for me. Can Riverhawk sell me a system that uses a fluid that I can use?
A) Yes, Riverhawk has provided hydraulic systems that use food grade oils as well as systems that use water for oil sensitive applications.
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Q) Can Riverhawk Hydraulic nuts be used in high temperature applications?
A) Yes, Riverhawk HTN's are designed using metal seals which are less temperature sensitive than elastomeric ones. Contact us, our engineering department can help you to apply hydraulic nuts in your challenging environment.
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Q) Can Riverhawk design fasteners for high vibration environments?
A) Yes, Riverhawk regularly designs nuts that must survive high vibration. We offer solutions that fight loosening as well as reducing internal fretting.
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Hydraulic Torque Coupling
Q) Why would I want to choose a Riverhawk Hydraulic Torque Coupler over a mechanical clamp?
A) The Riverhawk HTC is offers a number of advantages:
- It will actuate much faster than a screw type, especially in larger units.
- It will generate a much more accurate clamp load.
- Riverhawk HTC's are specifically designed for high speed operation.
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Q) Can I use a Riverhawk HTC to mount a hub on a tapered shaft?
A) Yes. HTC,s function well holding tapered hubs on. You should use the same retaining nut as you would otherwise use.
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Q) Can I use an HTC as part of a field repair of a damaged shaft end?
A) Yes, HTC,s are great for salvaging damaged shaft ends. There are many ways to do it that depends on your situation so contact us and we will help you through.
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Q) Can I use a Riverhawk HTC to salvage a hydraulic shaft end?
A) Yes, replacing a traditional hydraulic fit with an HTC fit is quick and easy. From a field prospective, dressing a damaged shaft for HTC retrofit is far easier than dressing one to seal hydraulic fluid.(link)
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Q) Can I hse a Riverhawk HTC on a keyed shaft end?
A) Yes, although HTC's are designed to eliminate the need for keys, many shafts already have them. You can either fill the shaft key way and use friction to drive or squeeze over keyed joint to add integrity to it. Contact us and we will help you determine the best way for you.
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VRD
Q) Why is the Riverhawk Viscous Rotational Damper better than rubber couplings?
A) The VRD offers a number of benefits over rubber damping couplings:
- Rubber elements are exposed to air and harden with time. The VRD transmits torque through steel and the damping fluid does not degrade.
- Rubber elements heat easily and soften. The VRD damper is specially designed to dissipate heat.
- Rubber element couplings are heavy and difficult to balance. The VRD is very light and well designed for high speed operation.
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Q) Can a Riverhawk Viscous Rotational Damper be tuned to specifically dampen my machinery vibrations?
A) Yes, Riverhawk custom designs each VRD and will work with you to design one that meets your vibrational needs.
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