Hardware takes you to understand metal spiral wound gaskets

Before installing the metal spiral wound gasket, we must understand the precautions for its installation, so that it can better play its role. It can also reduce the chance of some failures when the equipment is working. For the winding part of the metal spiral wound gasket, we must remember that in the flange sealing surface, we cannot casually set the width of the winding part according to our own ideas, because this behavior will affect the ability of the bolt. Therefore, the sealing performance of the gasket will not be able to achieve the expected effect. And for the spiral wound gaskets of some basic gaskets, it is better not to use them on some flanges with concave and convex surfaces. Why do we say that? This is because if you do this, it will easily cause the solder joints in the gasket to open during the work process, so that the existence of the gasket itself becomes meaningless. In some high-temperature environments, we should pay attention to the material of the inner inner ring. Some vibrating working environments are also what we need to pay attention to. When selecting flange gaskets, we have noticed its sealing performance, creep, compression and recovery rate. These test data can be used to understand the precautions for installation before installing metal spiral wound gaskets, so that we can Let it play its role better. Prompt the user which gasket material and form to use, and make a reference for the selection of gaskets, because these parameters are interrelated and affect each other, so you can't just consider one of the two as a reference when choosing. These factors should be fully considered. 1. Compression and recovery rate The compression rate refers to the effect on the thickness under a specific load, and the recovery rate refers to the increase in the thickness after the load is removed. The high compression rate of the gasket indicates that it can be used on irregular surfaces, the flange surface is more adaptable, and can increase friction, making the gasket difficult to blow out and reducing the probability of leakage. The recovery rate indicates the elastic performance of the gasket. A gasket with a high recovery rate generally requires a greater pressing force to maintain a good seal. 2. Sealing ability All gasket seals have leakage. The ideal state of gasket sealing when there is zero leakage. In any case, good sealing performance can reduce product loss, improve safety and save costs. If the gasket has leaked at room temperature, the situation at high temperatures may be more serious. A 0.8mm thick gasket can be used for testing. The thinner the gasket, the better the sealing ability, because the less material the medium can pass through. In practical applications, a lot of 1.5mm or 3mm thickness gaskets are used, and the temperature is affected, so the leakage rate is higher. If the medium is a gas, the leakage rate is higher because the molecules of the gas are smaller and it is easier to pass through the gasket around and through the gasket. 3. Chemical adaptability The gasket may be corroded and decomposed by the chemical medium, causing serious leakage, so the gasket must be compatible with the medium. Only because the gasket enters the inner diameter of the pipe during installation, the gasket is rarely corroded, so the gasket generally does not fail soon after assembly, and it takes a certain time for the medium to pass through the entire gasket. Some gaskets will swell in certain media. In this case, even if the gasket is not compatible with the media, the gasket can still play a sealing role in a short time. The safe choice is that the gasket cannot be corroded by the medium, so most gasket manufacturers will provide the chemical properties (PH value) of the product. 4. Gasket creep Creep will cause the load to be reduced. If the load is reduced or lost, the friction between the gasket and the flange surface will decrease, which will easily cause leakage or even blow out the gasket. If the gasket has a large creep, it is necessary to tighten the flange regularly, which increases the labor intensity. 5. Temperature Temperature is one of the key factors in gasket selection. Temperature has different effects on gaskets of different materials. At high temperatures, the filler may evaporate and the elastomer will solidify and become hard; at low temperatures, the gasket will easily lose its elasticity and become brittle. At low temperatures, tightening flanges generally does not improve the sealing performance, but will break the gasket. Gaskets used at extremely low temperatures should generally be kept clean and dry. 6. Pressure The maximum pressure that the gasket can withstand is closely related to the temperature. Most gaskets cannot be used in conditions where both temperature and pressure are at the limit. At high temperatures, the pressure bearing capacity of the gasket will decrease; similarly, at high pressures, the temperature bearing capacity will also decrease. 7. Gasket thickness If the chemical compatibility, temperature and pressure have been clarified when the gasket is selected, there is still one thing to determine is the maximum thickness of the gasket. In many cases, it is best to choose the thinnest gasket. Because the thinner, the smaller the contact area with the medium, the smaller the way for the medium to leak through the gasket, and the higher the pressure-bearing capacity. And more economical. If the flange surface is rough, we recommend using thicker gaskets to compensate for the unevenness of the flange surface to achieve a sealing effect.