Valve sealing

Are you in design? If you give the parameters to the manufacturer, they will definitely know. For example, in the case of gases, if the pressure difference is low, a soft seal can be used; whereas when the medium has a high erosive property, a hard seal must be used

The medium inside the pipeline is an adhesive (rubber emulsion)

Hard seal: A seal where both sides of the sealing pair are made of metallic materials or other hard materials is referred to as a “hard seal”. This type of seal has poor sealing performance, but it is resistant to high temperatures, wear, and has good mechanical properties. Examples include steel+steel; steel+copper; steel+graphite; steel+alloy steel; (here, the steel can also be cast iron or cast steel, and the alloys can be those applied through cladding or spraying). Soft seal: A seal where one side of the sealing pair is a metallic material while the other side is an elastic non-metallic material is called a “soft seal”. This type of seal offers better sealing performance, but it is not resistant to high temperatures, is prone to wear, and has poor mechanical properties. Examples include steel+rubber; steel+tetrafluoroethylene, etc. In a soft seal, one side of the sealing pair is made of a material with relatively low hardness. Generally, the soft seal seat is made of non-metallic materials that possess certain strength, hardness, and temperature resistance; it provides good sealing performance and can achieve zero leakage, but its lifespan and adaptability to different temperatures are relatively poor. Rigid seals are made of metal, and their sealing performance is relatively poor, although manufacturers claim that zero leakage can be achieved. Soft seals cannot meet the process requirements for some corrosive materials, but hard seals can solve this issue! These two types of seals can complement each other; in terms of sealing performance, soft seals are relatively better, but nowadays hard seals also meet the required standards! The advantage of soft seals is their good sealing performance, while the disadvantages are that they tend to age and wear out easily, resulting in a short service life. Rigid seals have a long service life, but their sealing performance is relatively inferior to that of soft seals.

This post was last edited by 19751107w on 2010-11-5 at 15:55. The soft and hard seals of a valve are related to pressure, temperature, and the medium! Under normal temperature and pressure, and with conventional media that contain no particles, a soft seal can be used. When the temperature is above 150 degrees, or when the medium contains particles that cause severe erosion of the valve seat, a hard-sealed valve should be chosen!