The trapezoidal groove represents a special design of the installation space for O-rings as a flange seal.
The groove flanks form a trapezoid with the groove base. The usual angle for aligning the groove flanks is approx. 25 degrees. The width of the groove is measured at the top edges of the groove and specified so that the groove holds an inserted O-ring.
Due to the special geometry, the production of this groove is very complex. The trapezoidal groove is also known as a dovetail groove and also exists as a half trapezoidal groove.
#1 Definition trapezoidal groove
The trapezoidal groove is a special installation space for O-rings in which the groove flanks form a trapezoid with the groove base. This groove shape is suitable for flange gaskets.
#2 Meaning of the trapezoidal groove
The standard design of an O-ring installation space as a rectangular groove is only deviated from for special requirements.
The trapezoidal groove can fix O-rings in the installation position for overhead installation and prevent them from falling out. This has advantages if the sealing point is opened and closed regularly.