Basic introduction
The hydraulic bolting system consists of a hydraulic torque wrench, a hydraulic pump, and a high-pressure hose.
Hydraulic torque wrenches are specifically designed for applications where space is limited and/or particularly high output torque is required. The design of a hydraulic torque wrench utilises the far higher leverage forces generated by a hydraulic piston, using high-pressure hydraulic power supplied by an air- or electric-driven pump. The hydraulic piston is connected to a ratchet via a reaction pawl assembly, which allows it to engage the ratchet teeth in the advance mode to rotate the nut or bolt head, and subsequently release during piston retraction to re-engage in the next forward push position. All hydraulic torque wrenches operate at a maximum hydraulic pressure of 700 bar, incorporate a double-acting, heavy-duty hydraulic piston for fast, easy operation, and can be used to accurately tighten or loosen nuts/bolts. A choice of standard square-drive tools, suitable for use with a variety of torque wrench socket sizes, or hexagon-drive cassette head tools that locate directly onto the nut/bolt, is available.
A hydraulic torquing tool is a professional bolt-tightening tool used for bolt installation and disassembly, powered by hydraulic pressure and providing high torque. It is often used to tighten and loosen bolts larger than one inch. The maximum output torque of the torquing equipment can reach 140,000 Nm, improving work efficiency, reducing labor intensity, enhancing installation quality, and contributing to site safety management.
Hydraulic Wrench Classification
There are two series of hydraulic torque machines: square-drive hydraulic wrenches and low-profile hydraulic wrenches. As the name implies, the square-drive hydraulic wrench relies on the drive shaft to rotate the corresponding impact socket to pre-tighten the nut. As long as the torque range allows, the corresponding high-strength socket can be replaced to complete the bolts of different specifications. It is a general-purpose hydraulic wrench. The scope of application is wider. The low-profile hydraulic wrench is also called a low-clearance wrench or cassette-type wrench. It can be equipped with a reducer if used with a smaller-size bolt. Generally, it’s used for these conditions: for example, when the working space is relatively small, double nuts or bolts are too small, the nut and the equipment wall are too small, etc.
Application
The scope of use of hydraulic wrenches is very wide. In shipbuilding, petrochemical, construction, electric power, mining, metallurgy, and other industries, hydraulic wrenches are a vital tool for installing and removing large bolts. It is irreplaceable with other tools. Not only is it easy to use and lightweight, but it also provides huge torque and is very accurate. The torque repeatability is about 3%. According to relevant statistics, about 50% of equipment failures in operation are caused by bolt problems. At the same time, the number of major equipment accidents caused by bolt problems is also staggering. Therefore, tighten the bolts during equipment installation, maintenance, and gun repair. Torque requirements for fixing and disassembly are strict in most cases, and it is difficult to meet them with manual methods. For high-torque bolts, hydraulic wrenches are the ideal choice.
In many cases, to improve fastening accuracy, a hydraulic wrench synchronization system is also used. The main purpose is to avoid the unilateral pressure mode on the flange surface, which can cause the gasket to fail due to excessive extrusion and leakage. The synchronization system uses two or four hydraulic wrenches, each connected to a single pump. According to the hydraulic principle, multiple hydraulic wrenches operate simultaneously and output the set torque to achieve parallel flange closure, with torque accuracy up to 3%. The synchronization system can lock the bolts at once, whereas the single system must be loaded multiple times and locked step by step. It can be seen that the synchronization system’s efficiency is far greater than that of the single system.