Elliptical heads, also known as dished ends or ellipsoidal heads, are critical components used to seal the ends of pressure vessels, boilers, and large-diameter pipelines, offering exceptional corrosion resistance and structural integrity. These heads are vital for boiler pipeline protection and erosion/corrosion resistance in industries such as petrochemical, power generation, chemical processing, and oil and gas.

Compliant with standards like DIN 28011, ASME UG-32, and EN 13445, elliptical heads feature a 2:1 ratio (major to minor axis), optimizing stress distribution and pressure resistance. They are available in sizes up to 72″ (DN1800), with wall thicknesses up to 200 mm, and are manufactured from materials such as carbon steel (HII, P265GH), stainless steel (304, 316L, 1.4541, 1.4571), or alloy steel (15Mo3, 13CrMo44, 10CrMo910). Surface treatments like pickling, passivation, or Fusion Bonded Epoxy (FBE) coatings enhance durability in corrosive environments.

Elliptical heads undergo rigorous testing, including chemical analysis (e.g., HII: C ≤0.16%; 316L: C ≤0.03%), tensile testing (HII: YS ≥235 MPa, TS ≥360-510 MPa; 316L: YS ≥205 MPa, TS ≥515 MPa), hydrostatic testing (up to 9.8 MPa), and nondestructive methods (radiographic, ultrasonic, PMI). With densities of ~7.85 g/cm³ for carbon steel or ~8.0 g/cm³ for stainless steel, and suitability for temperatures up to 450°C (carbon steel) or 870°C (stainless steel), these heads excel in high-pressure vessel applications like boilers, heat exchangers, and refinery systems.

The ellipsoidal design ensures uniform stress distribution, making elliptical heads ideal for sealing pressure vessels and pipelines in harsh, corrosive settings, such as chemical plants, offshore platforms, and power generation facilities.

The elliptical head ( or named ellipsoidal head ) which is a head consisting of two parts: a rotating ellipsoidal sphere and a cylindrical straight section. Elliptical tank head is fabricated to have a certain shape instead of a particular dish radius or knuckle radius. The dish radius is approximately 90% of the diameter and the knuckle radius is approximately 17% of the diameter. 2:1 elliptical flanged and dished heads are ASME compliant.

What should be considered in the selection of the heads?

1. Customer requirements.
2. Requirements of Chemical Process.
3. Conical heads are used for vertical vessels of solid masses to facilitate the flow and discharge of masses. Elliptical head or spherical head for liquid masses.
4. Stirred pressure vessels should determine the shape of the head according to the shape of the slurry leaf and the flow form of the working mass.
5. According to the pressure. For medium and low pressure pressure vessels, ellipsoidal heads are mostly used. For high pressure and ultra-high pressure pressure vessels, spherical heads are mostly used.
6. Determine from the analysis of considering the stress situation. If the stress transition zone of ellipsoidal head is opened with larger openings and the local stress is too large, spherical head can also be considered.