Blind Flange

This is a flange without a bore and is used to shut off a piping system or vessel opening. It also permits easy access to vessels or piping systems for inspection purposes. Blind flange can be supplied with or without hubs as per Clients requirement.

Slip-On-Flange

The flange is slipped over the pipe and then welded both inside and outside to provide sufficient strength and prevent leakage. This flange is used in preference to weld necks by many users because of its lower cost and the fact that less accuracy is required when cutting pipe to length.

Weld Neck Flange

This is designed to be joined to a piping system by butt-welding. It is relatively expensive because of Its long neck, but is preferred for high stress applications. The neck or hub transmits stresses to the base of the hub to the wall thickness at the butt weld, provide important reinforcement of the flange. The bore of the flange matches the bore of the pipe, reducing turbulence and erosion.

Threaded Flange

This is similar to a slip-on flange in outline, but the bore is threaded, thus enabling assembly without welding. This obviously limits its application to relatively low pressure piping systems. The flange may be welded around the joint after assembly, but this is not considered a satisfactory method of increasing its applications.

Socket-weld Flange

This is similar to a slip-on flange in outline, but the bore is counter-bored to accept pipe. The diameter of the remaining bore is the same as the inside diameter of the pipe. The flange is attached to the pipe by a fillet weld around the hub of the flange. An optional interval weld may be applied in high stress applications. Its biggest use is in high pressure systems such as hydraulic and steam lines.

Lap Joint Flange

This is again similar to a slip-on flange, but it has a radius at the intersection of the bore and the flange face to accommodate a lap stub end. The face on the stub end forms the gasket face on the flange. This type of flange is used in applications where section of piping systems need to be dismantle quickly and easily for inspection or replacement.

Spectacle Flange

This is a pressure retaining plate with one solid end and one open end connected with a web or tie-bar. In normal operation, the open end forms the seal between two flanges and permits normal flow of fluid through pipe work. If the solid end is swung into position it effectively blanks of the pipe and halts the flow.

Long Neck Flanges

These flanges are unique due to their simple connectivity with other pipes and applied for linking purposes mostly used in refining industries.

Groove & Tongue Flange

The Groove and Tongue faces of this flanges must be matched. One flange face has a raised ring (Tongue) machined onto the flange face while the mating flange has a matching depression (Groove) machined into its face.
Tongue-and-groove facings are standardized in both large and small types. They differ from male-and-female in that the inside diameters of the tongue-and-groove and do not extend into the flange base, thus retaining the gasket on its inner and outer diameter. These are commonly found on pump covers and Valve Bonnets.
Tongue-and-groove joints also have an advantage in self-aligning and act as a reservoir for the adhesive. The scarf joint keeps the axis of loading in line with the joint and does not require a major machining operation.

Orifice

The function of an orifice flange is to provide access to a line for metering of gases or liquids. An orifice plate is clamped between a pair of flanges when installed in a line and the whole assembly is refer to as an orifice flange union. Jack-screws within the assembly facilitate removal of the orifice plate. The orifice plate, the metering device, consists of a thin plate with a concentric, square edge, circular hole in the centre. Two pressure tap-holes are drilled in each flange to measure pressure difference through the orifice.