Why use hydraulic wrench?
Hydraulic wrenches can control the preload of bolts more accurately and reliably, have large output torque, are easy to use, and can be used in narrow spaces. This is particularly important for some large infrastructure and large electromechanical equipment that use a large number of high-strength bolts, especially heavy machinery and equipment that bear loads and strong impact vibrations, and industries that need to ensure the sealing of pipeline containers.
What information is included in this article?
Below, taking the application of hydraulic torque wrenches in refineries and deep-sea assembly as an example, it is explained that hydraulic torque wrenches have been widely used in the petroleum and petrochemical industry. There are many detachable connection methods between the equipment and pipelines in refineries, and the most commonly used is flange connection.
According to statistics, a refinery with an annual output of 2.5 million tons has more than 200,000 flange connections. The failure of flange connections is mainly manifested as leakage. Since most of the refineries are flammable, explosive, highly toxic or corrosive materials and media, major fires or personal injury accidents caused by flange leakage have occurred frequently, so it is necessary to pay attention to the sealing of flanges.
The factors that cause flange leakage are as follows:
1.Flange problems: including flange sealing surface type problems, flange sealing surface surface roughness not meeting requirements, insufficient flange rigidity, etc.
2.Gasket performance problems: including gasket material not dense enough, insufficient resistance to temperature and pressure fluctuations and medium corrosion, poor deformation rebound ability and small permanent deformation performance, insufficient hardness difference between flange and gasket, etc.
3.Bolt preload problems include the bolt preload not acting evenly and symmetrically on the gasket, the bolt preload is too small or too large, etc.
4.Use conditions Use conditions mainly refer to the system pressure, temperature, and physical and chemical properties of the medium. The influence of simple pressure or medium factors on sealing is not the main one. Only when combined with temperature, especially under the action of fluctuating high temperature, will the performance of the seal be seriously affected.
5.Installation problems include: the flange surface cleanliness and roughness do not meet the requirements, there are mechanical damage and corrosion damage, and there are old gaskets left; the bosses on the flange surface cannot be aligned; the gap between the two flange surfaces is too large; the parallelism of the two sealing planes must meet the requirements of the gasket type used; the form, material, size and bolts of the gaskets are not in compliance with the specified requirements; the bolt preload is uneven, the installation procedure is wrong; the gasket compression is insufficient; and maintenance and repair are not carried out in time, etc.
6.Other problems include pipeline system layout, vibration, insufficient flexibility and stress of the pipeline, etc.
All of the above problems are hidden dangers that cause flange leakage. In order to achieve a safe and leak-free flange connection, it is particularly important to correctly preload the bolts and install the flanges while ensuring that the performance of the flanges and gaskets meets the requirements.
The application of hydraulic wrenches in refineries
Bolt force control is one of the main factors to ensure the sealing of the flanges, because the flange sealing is achieved by tightening the bolts to compress the gaskets. When pre-tightening the bolts, the gaskets are compressed by the flanges, causing elastic or plastic deformation of the gaskets, thereby filling the tiny unevenness on the flange surface to achieve sealing. During operation, the gasket can also have a large residual sealing pressure to maintain a good sealing state. The bolt preload must be applied evenly and symmetrically to the gasket. If the preload is too small, the gasket cannot stop leaking without being compressed. However, if the preload is too large, the gasket will often produce excessive compression deformation, causing the gasket to lose its rebound ability or even be damaged.
Summary
Using a hydraulic torque wrench, the bolt preload can be applied evenly and symmetrically to the gasket, thereby achieving a balanced and effective bolt load and completing the correct installation of the flange. Through the bolt tightening solution, the bolt tightening operation is not only simpler and more efficient, but also safer, more reliable, and more precise, which greatly reduces the labor intensity of workers and reduces the risk of flange seal leakage. Moreover, the technical center not only provides first-class products, but also provides many customized services. This is the core competitiveness of hydraulic wrenches.