The principle of high temperature pre tightening Belleville spring
The high-temperature pre tightening Belleville spring is a kind of elastic mechanical element with special material, which can provide enough pre tightening force load under small deformation through the structure shape determined after accurate calculation, and can be installed on both sides of flange bolt, thus effectively reducing the risk of seal failure. It is usually used in combination with floating preloading process. Generally, a high-temperature preloaded Belleville spring is installed on both sides or one side of each bolt to meet the deformation compensation needs in most cases. In special cases, the combination of multiple Belleville springs can also be used for compensation. When using the high temperature pre tightening disc spring, sometimes the disc spring will be crushed. The main reason for this situation is that the pre tightening force is too large and the halogen ion corrosion. In the actual installation of high-temperature disc spring, special attention should be paid to: do not use a sledgehammer to smash, knock, or hammer to chisel with force. If the force is overloaded, the disc spring will break or crack! The installation method should be strictly followed.
Characteristics of high temperature preloaded Belleville spring
1. The vibration of mechanical equipment during operation will lead to the change of pre tightening force. The high-temperature pre tightening Belleville spring can effectively absorb mechanical vibration, avoid bolt loosening caused by mechanical vibration, and ensure long-term and reliable sealing.
2. In the application condition, the environment of hot expansion and cold contraction will lead to repeated changes in the preload. The high-temperature preloaded Belleville spring has super compensation function. The high-temperature Belleville spring compensates the repeated changes in the preload caused by hot expansion and cold contraction, so as to keep the preload stable and prevent bolt fatigue and gasket failure.
3. The change of medium pressure results in the change of preload. The high temperature preload Belleville spring can compensate for the change of preload caused by the change of medium pressure and prevent the failure of bolt and gasket.
Technical standard for high temperature preloaded Belleville spring
1. Design and production standards of high temperature preloaded Belleville spring din2092, din6796 and GB / t1972-2005
2. The inspection standards of high temperature pre tightening Belleville spring din2092, din6796 and GB / t1972-2005 ensure the product quality.
3. Material standard is ASTM A681 (American Society for testing and materials)
Application of high temperature pre tightening Belleville spring
High temperature pre tightening Belleville spring is mainly used for pre tightening bolts of various flanges in high temperature environment. For example, the flange bolts of various pipeline flanges, valves, heat exchangers, reactors, agitators, pumps, centrifuges, etc. are pre tightened. In particular, the temperature difference is more than 100 ℃. Common specifications m8-m72, Othello seal company can also design and manufacture according to user requirements.
Its shape is tapered (as shown in the figure). It can bear the load when used on the shaft. When the load is deformed, the high-temperature pre tensioned Belleville spring can store certain potential energy. When the bolt is loose, the high-temperature pre tensioned Belleville spring can maintain the pressure between the flange connections by releasing part of potential energy, so as to achieve the sealing effect. The stress distribution of high temperature preloaded Belleville spring decreases uniformly from inside to outside, which can achieve the effect of low stroke and high compensation force. For example, in the application of heat exchanger in industrial pipeline system, because the temperature of heat exchanger in the pipeline will change, the pipeline will show expansion or contraction phenomenon when the temperature is different. The high temperature preloaded Belleville spring can maintain a constant pressure to support the system in different temperature and pressure environments. This stability can play a good role in sealing. At the same time, the high temperature pre tightening Belleville spring can achieve greater pressure under smaller displacement, which is of great significance to the flange with smaller space such as heat exchanger.
After tightening the bolt, the high-temperature pre tightening Belleville spring can convert the absorbed mechanical energy into potential energy and store it. When the equipment is subject to the change of temperature or pressure and other external forces in use, the released potential energy will be converted into mechanical energy, so as to compensate the pre tightening force of the bolt and ensure that the pre tightening force of the bolt is always within the pre tightening force range required by the high-temperature pre tightening Belleville spring
