Tensioning is the direct axial stretching of the bolt to achieve preload. Inaccuracies created through friction are eliminated. Massive mechanical effort to create torque is replaced with simple hydraulic pressure. A uniform load can be applied by tensioning multiple studs simultaneously.
Tensioning requires longer bolts, and a seating area on the assembly around the nut. Tensioning can be done using detachable Bolt Tensioners or Hydraulic Nuts.
Load loss is a loss of bolt elongation depending on factors such as thread deflections, radial expansion of the nut, and embedding of the nut into the contact area of the joint. Load loss is accounted for in calculation and is added to the preload value to determine the initial
Applied Load. The preload depends on Applied Load and Load Loss (load loss factor).
Manufacturer’s rating of pressure and load are maximum safe limits. Good practice encourages using only 80% of these ratings!
Tensioning permits the simultaneous tightening of multiple bolts; the tools are connected in sequence via a high-pressure hose assembly to a single pump unit. This ensures each tool develops the exact same load and provides a uniform clamping force across the joint. This is especially important for pressure containing vessels requiring even gasket compression to affect a seal.
Step 1: The bolt tensioner is fitted over the stud
Step 2: Hydraulic pressure is applied to the tensioner which then stretches the stud
Step 3: The stud’s nut is wound down against the joint face
Step 4: Pressure is released and the tool removed
The bolt behaves like a spring, when the pressure is released the bolt is under tension and attempts to contract, creating the required clamping force across the joint.
Less than 100% Tensioning
Not all applications allow for the simultaneous fit of a tensioning device on each bolt, in these cases at least two tensioning pressures are applied. This is to account for a load loss in those bolts already tensioned as the next sets are tightened. The load losses are accounted for in calculation and a higher load is applied to allow the first sets to relax back to the target preload.
Set-up using a 100% tensioning procedure
All bolts are tensioned simultaneously.
Set-up using a 50% tensioning procedure
Half the bolts are tensioned simultaneously, the tools are relocated on the remaining bolts and they are subsequently tensioned.
We have done business with Winnellie Hydraulics on numerous occasions and find them to always be nothing but professional, honest and reliable.Their customer service is excellent and they are always a pleasure to work with. We would highly recommend Winnellie Hydraulics and we look forward to continuing business with Max and the team in the up and coming future.
Winnellie Hydraulics are up most professional and I am always impressed with the service offered and provided. The team at Winnellie Hydraulics are highly skilled, innovative and ever reliable. They continue to be the Territory’s leading service specialists within the fields of the hydraulic and pneumatic services and solutions. The team have a broad range of knowledge in hydraulic, pneumatic, hose management and products across a extensive range of divisions. The team at Winnellie Hydraulics are easy to work with and really appreciate their customers and strive for continuous business improvement.
Efficient, professional and dedicated. The team at Winnellie Hydraulics are a pleasure to work with and are customer service specialists.Max and the team have taken on many challenges to assist with emergent scopes at our onshore facility in Darwin. They go above and beyond to meet the timeline required without missing a beat on quality.I highly recommend dealing with them and look forward to future business.Thanks guys
The team at Winnellie Hydraulics are customer service specialists! They certainly go above and beyond to meet the needs of customers and are a great local service and supply business. I highly recommend dealing with them.
For all your Hydraulic & Pneumatic needs, Winnellie Hydraulics has you covered.Max and the team run a great operation that supports the Oil & Gas and Mining industries.With great brands supporting them, they are truly the one stop shop for all your engineering needs.
The team at Winnellie hydraulics, is great to work with, they understand our priority and service delivery to our Defence clients, No job too small or big and delivering of high quality products and service. Also really easy to deal with in regards to faults/ warranty and SME service . Highly recommended to use.
Winnellie Hydraulics are a Parker PPD for the NT which means they have full access to all Parkers Hannifin products & our local Engineering team in Australia who can work with Winnellie on any projects where clients needs are meet using Parkers products & their insulation experience
Outstanding commitment to their customers, in my experience there isn’t anything that is too hard for this mob. Always prepared to find solutions to their customers now matter how big or small the request. A great family business who take pride in providing product and service.