Before we start talking about different types of torque wrenches, it is important to know what a torque wrench is. A torque wrench helps apply the required amount of torque on a fastener such as a nut or a bolt to either tighten or loosen it. When applying the high value of torque, these wrenches would require a reaction arm that would lock itself at an adjacent point (As Newton’s 3rd law states, every action requires an equal and opposite reaction).
The fastener ideally should be lubricated before starting the process. This article will talk about the different types of torque wrench with their advantages and disadvantages. While there are many different types of torque wrenches, we will focus on the automated high newton meter capacity torque wrenches.
Hydraulic Torque Wrench
The most common and popular torque wrench in the industry is a hydraulic torque wrench. Powered by hydraulics (oil), it offers the highest power to weight ratio, which means that it offers the widest range of toque inversely proportionate to the weight of the tool. It also offers the most accurate torque output with +/- 3% accuracy. Therefore, the hydraulic torque wrench offers portability and flexibility of usage. Hydraulic Torque Wrenches are available in a square drive (external socket required) and direct fit (hex) drive variants.
Since Hydraulic Torque Wrenches are capable of achieving high torque values, placement of the reaction arm becomes critical to protecting the housing of the tool from an unwarranted external force. Ideally, the reaction should be taken in a plane parallel to the axis of the bolt. The most common square drive hydraulic torque wrenches have the reaction mounted on the cylinder portion of the tool. The torque wrenches with the reaction arm mounted on the cylinder at the back have the disadvantage of the reaction arm not being parallel to the axis of the bolt when convenient reaction points are not available. Having the reaction arm mounted in the front of the tool, coaxial to the square drive provides a 360 degree plane. This ensures that when the reaction arm is rotated it will be always parallel to the axis of the bolt and also providing a stress free cylinder as the reaction arm is not mounted on the cylinder.
Prospective buyers should always consider the design of the square drive Hydraulic Torque wrench before considering a purchase.
Pneumatic Torque Wrench
The pneumatic torque wrench is powered by compressed air. Mostly popular in the automobile industry, it operates faster and provides an accuracy of +/- 5%. However, pneumatic tools need constant high air pressure due to which the tool cannot be operated at great heights.
Electric Torque Wrench
Unlike hydraulic and pneumatic torque wrenches, an electric torque wrench does not require a pump or compressed air to power them as it is directly connected to a power source like an electric socket. It offers an accuracy of +/- 5%. However, these tools cannot be used in all industries due to a possibility of spark generation which risks its usage in explosive industries like oil and gas, petrochemical and mining. The electric torque wrench also has the disadvantage of being heavy, having unbalanced weight, etc.
Battery Torque Wrench
The most modern torque wrench developed in industrial bolting, a battery torque wrench offers maximum portability as they do not require pumps or compressed air for power. These tools operate on battery placed at the bottom of the tool and offers an accuracy of +/-5%. These tools can be accessed anywhere as they are cordless torque wrenches and do not require any extension boards or hoses for power. However, the battery torque wrench offers lower maximum torque capacity as compared to hydraulic and pneumatic torque tools.
In conclusion, different torque wrenches are designed to provide options and solutions based on industry requirements and specifications. This provides the customer with the flexibility to choose which wrench suits their requirements best. Visit us next time to know more about industrial bolting.