Convex disc head (Convex Disc)
A shallow section of a sphere, with no separate knuckle
A convex disc head consists of a shallow spherical section whose crown radius (CR) can reach the vessel's outside diameter (Do), with a minimum of 0.8×Do. Unlike torispherical, this head has no separate knuckle and joins the cylindrical body directly.
What is a convex disc head?
A convex disc head consists of a shallow spherical section whose crown radius can reach the vessel's outside diameter, with a minimum of 0.8×Do. Unlike torispherical, it has no separate knuckle and is joined directly to the shell.
Its approximate depth is about 0.134 times the outside diameter; an option between the plate type and torispherical in terms of depth.
Geometry formulas of the convex disc head
The crown radius is chosen between two standard values and the depth derives from it:
The closer CR is to Do, the shallower the head. Having no knuckle makes fabrication simpler, but the load capacity at high pressure is lower than torispherical.
Online calculation
See the head's dimensions, volume and weight for a real diameter and thickness
Convex disc head (Convex Disc)
Liquid level and volume inside this head
How the head is mounted
Development of this head (flat blank before forming)
The diameter of a flat plate of the same thickness and material that weighs the same as the formed head — an initial workshop estimate based on equal weight, not allowing for thickening or extra stretching at the knuckle.
The vessel head production process
From calculating the blank diameter to final edge preparation — the steps of making a vessel head in the workshop
Calculating the blank diameter
Cutting a disc from plate with the diameter and thickness calculated for the head type and vessel diameter
Cutting the plate blank
Precise cutting of steel or stainless plate by plasma, laser or gas according to the technical drawing
Pressing the head
Hot or cold forming of the disc with a die and industrial press until it reaches the final head profile
Edge preparation
Machining the edge, bevelling and preparing the weld area for fitting to the vessel shell
Video coming soonChoosing a head: the balance between pressure, cost and time
The main difference is the absence of a separate toroidal knuckle: in a torispherical head the transition from dome to body happens through a knuckle arc of smaller radius, while in a convex disc this transition is more direct. This simplifies fabrication at the cost of lower load capacity at high pressures.
Gallery of heads we have made
Convex disc head gallery
Applications and industries served
Buying heads from Behineh Ab
Six steps from first contact to delivery
Give the outside diameter, plate thickness, head type and required material.
The calculated weight, unit price and delivery time are sent the same business day.
Plate is supplied with the mill certificate and inspected on arrival before cutting.
Cutting the disc, hot or cold pressing depending on thickness, and checking dimensions with a template.
Machining the cylindrical edge and bevelling it ready for welding to the shell.
Packing, issuing the part identification sheet and shipping nationwide.
What sets us apart
Price inquiry
vessel head
Enter the diameter, thickness and head type; you will receive the calculated weight and unit price.
- Quotation with the exact weight of the part
- Standard heads delivered in 7 business days
- Shipping nationwide
