Tongue and groove (T&G) flanges are matched pairs in which a raised ring (the tongue) on one flange fits into a machined groove in the other. The gasket sits in the groove and is confined on both its inside and outside diameters, so it cannot blow out or be squeezed into the bore. This gives a very reliable, self-aligning joint for high pressures, hazardous fluids and equipment covers.
Raaj Fittings machines small and large tongue and groove facings to ASME B16.5 dimensions at our two plants in India, on weld neck, blind and other flanges in carbon, alloy and stainless steel, duplex and nickel alloys.
ASME B16.5 gives dimensions for large and small tongue and groove facings for each size and class; EN 1092-1 has equivalent tongue and groove facings (types C and D). Large T&G has a wider gasket area; small T&G a narrower one, used where higher gasket stress is wanted.
Tongue and groove confine the gasket on both sides, male and female only on the outside, and raised face not at all. T&G flanges must be ordered as matched pairs and cannot be bolted to raised-face or male-female flanges. Because the tongue is easily damaged in handling, it is protected during shipment and installation.
Every T&G flange is made from PMI-verified material, dimensionally inspected against the ordered standard and marked with material, size, rating and heat number. Orders are supplied with EN 10204 3.1 certificates; EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request.
The gasket is fully confined in the groove, on both its inside and outside diameters, so it cannot blow out or intrude into the bore, and the flanges align themselves on assembly.
No. A tongue mates only with a matching groove. T&G flanges must be ordered as pairs.
Both confine the gasket, but T&G confines it on both its inner and outer edges, while male and female confine it on the outer edge only.
The tongue is easily dented, so it is covered with protective caps or covers for shipment and should be handled carefully on site.