Pat Molloy, a high-force tools specialist with 15 years experience in industrial engineering, sales and service, is the National Bolting Manager for Enerpac . He has provided suggestions regarding the selection of torque wrenches.
The pressure to build pipelines throughout Australia makes it necessary that companies need a clear appreciation of the best technologies to get bolting jobs completed within deadlines and without costly failures. The right hydraulic torque wrenches can be brilliant for high-repetition tasks and have already halved the time taken for some construction and maintenance jobs, demonstrating their effectiveness on machinery and infrastructure ranging from trucks and bulldozers to pipelines, pumping stations, turbines and milling trains.
The first handwrenches can be found as far back as the beginning of the twentieth century, with a simple dial and pointer, operated by a spring mechanism. This was sufficient for small nut and bolt applications.
For heavy joints where high demands are made, speed and high repeatability is required and where torques of approximately 2,000 Nm to 27,000 Nm are used (such as for pressure vessels in the chemical industry, piping and heavy constructions) the manual method cannot be applied. Precisely adjustable hydraulic torque wrenches should be used.
The choice of torque wrench type and ancillary equipment depends on the application. Key aspects to consider are:
Accuracy and speed of operation: One is often useless without the other when embarking on highly repetitive tasks. Choose a tool that gives constant torque output to provide high accuracy across its full stroke (as in the case of the latest W and S Enerpac Hexagonal and Square drives).
Repeatability: Consistent torquing from one bolt to the next is crucial for applications ranging from fixed plant to mobile equipment and especially equipment under pressure, such as tanks and pipelines. Unequal torquing in a series of bolts is an invitation to disaster, through weak points that are built into the structure. Any bolt that may come loose causes downtime and if not spotted in time can cause failures in equipment. Where a large number of fasteners must have equal strength, tools such as the W low profile hexagonal wrenches and versatile S series square drive have terrific and precise repeatability across the entire range.
Tool construction: Match the tool to the toughness and duration of the job, because it can be a long drive back if something goes wrong. Steel comes into its own for rigorous, repetitive work and the robust W and S Enerpac torque wrench types are designed for maximum durability in the long haul, day in, day out. Reputable suppliers will give a good advice on the tool needed, because they know the business, value and safety.
Weight and Effort: Modern tool design should not make people pay a weight penalty, because even small increases in weight become larger and larger when people are doing the same job over and over again. To prevent fatigue and risk setting in, choose a tool with careful regard to weight, ergonomics, frequency of use and maneuverability around the job. Take the time to compare technologies such as the W low profile hexagonal wrenches for low clearance bolting applications. These weigh from only 1.4-5kg, while the versatile S series of double-acting square drive wrenches extends from 2.7-31kg.
Can the tool get the job done?
Generally, the rule of thumb is that the torque wrench should have 50 per cent more capacity than required for a particular task. That leaves a capacity reserve that can be necessary for unscrewing bolted joints. For heavy applications, wrenches of twice the capacity are sometimes used.
Is there enough space?
Apart from capacity data, questions have to be answered like: ‘is there enough height for using the wrench?’ and ‘is there enough space around the nut?’ As far as available working space is concerned, when height is sufficient, a square drive will be most satisfactory. But if height is limited, it will be better to choose a low model with cartridges.
Through application of light, high-tech materials and a one-piece wrench housing, the Enerpac torque wrenches are extremely compact. Their ratchet system has fine toothing, enabling high precision and preventing drive jamming. The double-acting cylinders give precise torque at high operating speeds. The compact high pressure design enables a high torque/weight ratio and offers more power reserve during operation. The swivel coupling can be turned 360 degrees at high pressure, so that the hoses can be positioned in any position. This is very important when working in tight spaces.
Latest wrenches from Enerpac are easy to handle and usable almost anywhere. Furthermore, the advantage of the hexagon cartridges and adapters is that these can be quickly replaced. No extra tools are necessary to do this.
Don’t forget the pump.
In addition to the wrenches themselves (or other hydraulically actuated controlled tightening technologies), consider the size and efficiency of the pumps you have to bring to the job. The pump may be the biggest tool that would be used, so getting the suitable power-to-weight performance is important.
Compact and portable electric pumps are often the speediest and most efficient solution for jobs close to base where reliable power supplies are available. Prime among these are the ZU4T Series electric pumps available. Weighing between 32-36kg, these cool running pumps are a radically new design with fewer moving parts to reduce weight and friction.
They also draw less current than comparable pumps. A self-priming first stage increases pump performance by supercharging the second stage piston pump, improving oil flow in both hot and cold weather operations. Patent-pending Z-class technology provides high bypass pressures for increased productivity, particularly in applications using long hose runs and in high pressure-drop circuits. Purpose-built bolting pumps such as the ZU4TE can be matched with pendant control for the safety of remote operation where required.
And what if there’s no power?
Sometimes jobs just do not have easy access to pneumatic or electric power. Sometimes maintenance crews, for example, might have to drive (or fly) great distances. In these circumstances, it might be best to employ an alternative technology such as a torque multiplier. The beauty of these manual tools is that they can provide outputs as much as 70:1 times as great as the input.
Where a torque wrench is preferred and has to carry with it its own source of power, there are special lightweight hand pumps available from Enerpac. The lightest of these is the P Series of aluminium-based pumps with durable glass filled nylon reservoirs, weighing from 2.4 to 10kg.
It is often advisable to select a two-stage type (which offers a fast actuating first stage for rapid setup, then a second stage delivering more power and greater oil flows for the job). Education and training beforehand: As with all selections of tools for use in remote, rugged and high-safety environments, correct training is essential to get the best precision, efficiency and safety from the tools.
And backup afterwards Many opportunists with limited or no experience of hydraulics are now bringing in torque wrenches which they cannot back up nationally now. Companies such as Enerpac have built their reputation more than 50 years as an industry leader throughout Australasia, backed by a national sales and service network that extends into every corner of their market.
Enerpac’s family of fastening technologies. Enerpac offer advanced torque wrench and pumping technology backed by more than 50 years of application expertise in Australasia and globally. Rigid steel torque wrenches from Enerpac are manufactured with quality power- to-weight ratios, are not stand-alone products but form part of complete families of advanced bolting and fastening technologies to handle the toughest jobs onshore and offshore.
The new wave of technology includes:
- Versatile square and hexagonal drive torque wrenches The W low profile hexagonal wrenches for low clearance bolting applications weigh from only 1.4-5kg yet have terrific and precisely repeatable torque from 2712-20337 Nm, while the versatile S series of double-acting square drive wrenches extends from 2.7-31kg with outputs of 1898-34437 Nm.
- A full range of top quality sockets precision crafted in world class ISO 9001 certified facilities.
- Precise and time-saving hydraulic nut families that are particularly useful in applications involving critical tolerances, multiple bolting tasks and high levels of repeatability.
- Powerful bolt tensioners and highly portable torque multipliers to provide from 1015-10,845 Nm of force for tightening and loosening of nuts, bolts and stubborn or corroded fasteners requiring high torque.
- Portable nut splitters, plus efficient flange splitting and flange alignment tools purpose-built to take manual labour out of the job while safeguarding the integrity of pipelines and flanged machinery – as well as the safety of the person working on them.
- Tough, reliable energy-efficient electric pumps including New-generation Z-class electric pump and new-generation Z-class air pump that have fewer moving parts for less friction, more reliability and reduced energy needs.
- Rugged workhorse pump and valving combinations custom engineered to particular applications, such as the ZU4908JE double-acting pump which can be coupled with compact and powerful Enerpac post-tensioning tools for mono strand construction applications common on resource and infrastructure development sites.