Size: 1/2 to 60inch, DN 12mm to DN 1500mm
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RTJ
Cabon steel: A105, A350 LF2
Stainless steel: A182 F304/F304L/F316/F316L/F321
Alloy steel: F11, F12
Packing: plywood case and plywood pallet
Keywrods: Spectacle Blind Flanges, Spectacle Blind Flange,
Spectacle Flanges, Spectacle Blind Flanges manufactory
Special bland flange
Standards, Dimensions & Weight
ASME B16.48 Class 150
ASME B16.48 Class 300
ASME B16.48 Class 600
ASME B16.48 Class 900
ASME B16.48 Class 1500
ASME B16.48 Class 2500
Can be attached to the pipe without welding (sometimes an
additional seal weld is used as well)
Ideal for higher pressure and temperature applications for small
Not recommended for larger loads, especially when subjected to
Uses of threaded flanges:
Threaded flanges can be fitted to pipes of various sizes without
welding and this is one chief benefit for which these flanges are
highly demanded. They can be used in extremely high pressure
applications, particularly at or near atmospheric temperature,
where the necessary post weld heat treatment is not possible.
They are ideal for small diameter piping applications.
They are economical and time saving devices.
These threaded flanges are normally designed for non-cyclic
The flanges are suitable to be used in applications where welding
They can be used in highly explosive areas.
These types of flanges are made from plate, and come in 3 different
The first and most widely used type are spec blinds - short for
spectacle: these are flanges with two equal outside diameter (OD)
parts welded together by way of a ‘bridge’. One of the parts also
contains an inside diameter (ID), while the other is a blank, or
blind. A whole is put at the halfway mark of the bridge. These are
also called spectacles, figure 8’s, and figure 8 blanks, because of
their resemblance to reading glasses (spectacles) and figure 8’s.
These are referred to as ‘Line Blanks’ in the ASME/ANSI standards.
The second and third types are quite similar: both have longer
bridges, referred to as ‘paddles’, which resemble longer handles.
One type has only an OD, and so is a blind plate - similar in
appearance to a large pizza oven peel. These are referred to as
paddle blinds. The other type is exactly the same but comes with an
ID as well, enabling flow-through when installed in a piping
system. These pieces have holes in the paddle which enables field
personnel to determine by sight which piece is installed in a
system. These are referred to as paddle spacers, and are often
supplied in sets together with the paddle blinds.
All 3 types of these flanges are used in piping systems or pressure
vessels where the flow needs to be interrupted from time to time.
They are installed between two pipe flanges (as specified above),
and by way of a screw inserted into the hole in the bridge or
paddle, they are able to rotate or ‘swing’ into and out of position
to interrupt or allow the flow, as the user sees fit. Our spec
blind flanges are available with raised, flat, or RTJ faces.