Nitinol Memory Smart Washer is an intelligent gasket that integrates sensing and execution. It is a temperature-sensitive control material made of NiTi memory alloy. It has become a new application field in the power industry. Its mechanical properties, corrosion resistance and service life are better than those of spring steel gaskets. It can withstand acid and alkali solutions for a long time without corrosion.
The most commonly used mechanical connection method for line connections and terminal blocks in power systems is bolt fixing, and a disc spring washer is installed under the nut to prevent loosening. However, since the power joints will creep over time in the use environment, the joint pressure will decrease, the joint will loosen, the contact resistance will increase, and heating will occur.
In addition, factors such as vibration and oxidation corrosion will also increase the occurrence of loosening and heating. Ordinary spring washers will cause severe oxidation corrosion due to the increase in heating temperature, causing the gasket to lose its elasticity, the fastening will fail, and it will enter a vicious cycle of loosening, increased contact resistance, heating, and more loosening, resulting in energy waste and even safety accidents.
Nitinol Memory alloy smart gaskets (IV generation) are made of new intelligent alloy materials. Automatically output different elastic forces according to temperature changes, restore its memory shape, and reduce the contact resistance of the joint. According to the increase in joint temperature, the elastic force of the gasket is automatically increased to reduce the contact resistance of the joint, effectively alleviating the heating of the joint and solving the problem of joint loosening. After the joint temperature exceeds the phase change temperature of the gasket, the joint contact resistance is reduced by more than 10% compared with the traditional gasket joint, saving electricity and reducing energy loss.
1. Principle of memory alloy smart gasket (IV generation):
Twist the memory alloy smart gasket from the natural state to the flattened state---the fastening system loosens due to vibration or change---the contact resistance increases---heat---the memory alloy smart gasket restores its shape, pressurizes the fastening system---the loose gap closes---the contact resistance decreases---the temperature decreases, thereby effectively suppressing the vicious cycle and achieving the purpose of energy saving and consumption reduction and reducing safety accidents.
2. Economic benefits of using memory alloy smart gaskets:
The Nitinol memory smart washer is used in a 110KV substation project with about 4,500 joints and 9,000 joints. After the project is implemented, if a certain joint is under normal load current of 400 amperes, when the joint temperature exceeds 45°C, the maximum temperature difference between the memory alloy gasket joint and the ordinary gasket joint is about 25°C. The contact resistance of the two joints is measured by comparative test.
