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1. The stretching mechanism of the stretcher is not affected by the lubrication effect of the bolts or the level of thread friction, allowing for more accurate determination of the bolt load. 2. The tensioner can simultaneously stretch multiple bolts, ensuring even force distribution across all the bolts and thus a balanced load. 3. Thanks to the use of state-of-the-art ultra-high pressure technology, the tensioner can remove and install bolts in a very small space. 4. The residual and effective loads obtained by tightening bolts using the stretching method of the stretcher are greater than those achieved using the torque method. 5. The stretching method used by the stretcher is more suitable for joining applications that require high precision in fastening; it enables the flanges to be joined under uniform stress, thus truly preventing leaks. Hydraulic tensioners are mainly used for fixed-torque tightening and removal of bolts of various specifications. The working principle of a hydraulic tensioner is to use a hydraulic cylinder to apply direct force to the bolt, causing the bolt to be stretched within its elastic deformation range; this results in a slight change in the bolt’s diameter, which in turn makes it easier to loosen the nut. The position of the axis of the mounting bolt of the hydraulic tensioner is used to apply axial tension to the bolt, thereby achieving the required degree of tension in it; it is this degree of tension that determines the clamping force needed to tighten the bolt. When the bolt is under tension, the nut separates from the flange surface. There is an opening at the lower end of the hydraulic tensioner, allowing the operator to turn the nut manually; usually, the nut is rotated by using a metal rod to move a lever attached to the hex nut (or by directly turning the round nut). By releasing the hydraulic pressure in the hydraulic tensioner, the nut and the joint surface press together, thereby locking the axial deformation of the bolt – that is, locking the remaining bolt load within the nut. The load applied by the hydraulic tensioner to the bolt is proportional to the oil pressure in the hydraulic cylinder; such a design allows for very precise control of the effective load. Since the load is applied directly to the bolt, and all forces are used to stretch the bolt, the space required by the load can be minimized.