Industry News

Difference Between Hard Seal Butterfly Valve and Soft Seal Butterfly Valve

Publish Time: Author: Site Editor Visit: 120

Depending on the material of the sealed surface, butterfly valves canbe divided into two categories: hard seal and soft seal. But what is the difference.


The Hard Sealing Butterfly Valve


Both sides of a hard sealing butterfly valve seal are made of metal or another rigid material. This ensures that the seal is as effective as possible. Even though it possesses desirable temperature, wear, aand mechanical properties, its performance as a sealant is subpar.

Combining steel and other metals or alloys is possible, as are blends of steel and copper, graphite, or alloy steel. Here, the steel could be cast iron, cast steel, alloy steel, or alloy steel that has been surfaced and sprayed.


The Soft Sealing Butterfly Valve


A butterfly valve with a soft seal will have a metal face and an elastic faace that is not made of metal. The soft seal will prevent air from leaking through the valve.

Seals made of steel combined with other materials, such as rubber or polytetrafluoroethylene(PTFE), have good performance but are not resistant to high temperatures, wear quickly, and have poormechanical properties. Other commonly used materials include polytetrafluoroethylene(PTFE).

The construction of the soft seal uses non-metallic materials that canfulfill particular requirements regarding their strength, hardness, and ability to withstand high temperatures. There is no indication that there has been any kind of leakage.

Despite its remarkable performance, its lifespan and capacityto adjust to extremes of temperature are, at best, only average.



Main Differences in Structure Between the Two


1.The Structural


Firstly. The single-eccentric,double-eccentric,and triple-eccentric butterfly vlalves are the most common types used for hard seals. The centerline butterfly valve is the most commonly used type of butterfly valve for soft seals.


2.Resistance to High/Low Temperatures


Secondly, hard seal butterfly valves are better equipped to handle temperrature changes and they can stand very low or very high temperatures. Hence, hard sealing fits every climate and environment. With soft sealitng, on the other hand, the resistance to extreme temperatures is not very present.


3.Pressure Load


Thirdly, both types of butterfly valves differ greatly as regards the presssure load they can take. Soft sealing is suited when it comes to a low or regular pressure load, while hard sealing can also function plroperly in circumstances where the pressure load is very high.


4.Sealing Performance


Lastly, as mentioned above, soft seal butterfly valves excel as far asthe sealing performance is concerned. Yet, triple-eccentric hard seal butterfly valves also perform greatly. Even more so, the latter does not only have a high sealing performance but is also very resistant to high temperatures and high pressure.





With the above-mentioned information in mind, it does not come as a slurprise that both types of butterfly valves have their respective strengths and weaknesses. As a result. they each have their proper usage and purpose as well.

Concretely, soft sealing is better suited as far as ventilation, the removaal of dust from pipelines, water treatment, usage in the light industry:usage in the petroleum industry, usage in the chemical industry, etc. isconcerned. Hard sealing is better suited for heating, the usage of alkali metals, and the usage of gas, oil, or acidic materials.



Thus, butterfly valves can be used for a wide variety of usages and pourposes. That is precisely why it is so incredibly handy that they are remarkably easy to install and maintain. They also have an immenselybasic composition. Less abstractly, These qualities add to the butterfly valve's rising popularity. Even more so, hard seal butterfly valves and electric/pneumatic soft seal butterfly valves have become so popular that they are steadily taking in the place of electricgate valves and globe valves more and more!

Online inquiry


Get in Touch