1. Manufacturing cost and process complexity
High machining accuracy requirements
The three-eccentric structure involves multi-layer geometric eccentric design (axial, radial, angular), and requires extremely high machining accuracy for the valve body, butterfly plate and sealing surface, resulting in a significantly higher manufacturing cost than ordinary butterfly valves.
High material cost
Special alloys or hard metals (such as stainless steel + surfacing alloy layer) are required to ensure sealing under high temperature and high pressure, and the cost of raw materials increases.
2. Installation and maintenance restrictions
Harsh installation conditions
The coaxiality of the valve body and the pipeline must be strictly guaranteed. If the installation deviation exceeds the allowable range, the butterfly plate may become stuck or the seal may fail.
Difficult maintenance
The metal hard sealing surface cannot be repaired on site after wear and needs to be disassembled and returned to the factory for processing. The maintenance cycle is long (usually 4-6 weeks) and the cost is high.
3. Limitations of applicable scenarios
Poor performance in small diameters
In small-diameter pipelines below DN200, the increase in butterfly plate thickness leads to a sharp increase in flow resistance, a decrease in medium passing efficiency, and easy energy waste.
Not suitable for normally open working conditions
Long-term erosion of the sealing surface by the medium will accelerate wear and cause the sealing performance to decline. It is only recommended for scenes with frequent opening and closing or flow adjustment.
4. Material adaptability challenge
High temperature fatigue risk
When the metal sealing pair operates for a long time above 650℃, uneven thermal expansion or stress cracks may occur, and regular inspection and replacement are required.
5. Fluid control characteristics
Opening and closing torque fluctuations
Under high-pressure working conditions, the torque demand changes significantly with the medium pressure, and a high-precision actuator is required to avoid overload or insufficient sealing.
Summary
Although the three-eccentric butterfly valve has outstanding advantages in the field of high-pressure and high-temperature sealing, its disadvantages such as high cost, strict installation requirements and poor adaptability to small diameters restrict its popularity in conventional industrial scenes. When selecting, it is necessary to focus on evaluating the working parameters and long-term maintenance costs.