What is a spectacle blind in piping?
Spectacle Blinds are simple safety devices that are installed between two pipe flanges. To stop the flow in the pipeline, the blind end is rotated into place between the flanges. This positively isolates the downstream piping and equipment. A Spectacle Blind is generally installed as a permanent fixture.
What is the difference between Spade and spectacle blind?
Difference between Spectacle Blind and Spade and Spacers Spade and Spacer combinedly comparable to Spectacle Blind. So, a spectacle blind is combined form of spade and spacer. For larger pipe sizes the weight of spectacle blind become too heavy. So sometimes, as the requirement arises, a spade or spacer is used.
What is a spectacle blind used for?
Spectacle Blinds are generally applied to permanently separating pipesystems, or just to connect with each other. A Spectacle Blind is a steel plate cut into two discs of a certain thickness. The two discs are attached to each other by section of steel similar to the nose piece of a pair of glasses.
What is a blind flange?
The blind flange is basically a flange that does not have a hub or a bored center. Blind flanges have the face thickness of a flange, a matching face type, and similar bolting pattern. Blind flanges can also be used to seal a nozzle opening on a pressure vessel.
How many types of blinds are there in piping?
Spectacle blind, spades, and spacers are also known as figure-8, paddle blank, Slip blind, and spacer. These are three different components that used in piping for positive isolation of the section of a line or equipment during maintenance and shutdown.
Where do you put spectacle blinds?
Spectacle Blind Installation Spectacle blinds install between two horizontal pipe runs. Instead of bolting the blind in place around the full circumference of the pipe like you would a pipe flange, you instead install it by inserting one of the flange bolts through the hole on the central tie bar.
What is the difference between spade and spacer?
Spades and Spacers The spacer (a ring-shaped plate) is used when the line needs to be open and the spade (a solid circular shaped plate) is installed when the line needs to be blocked or closed.
How do you install spectacle blind flange?
Adjusting spectacle blinds is straightforward. Simply loosen the bolts around the flange leaving the bolt running through the spectacle blind in place, rotate the desired face into the space between the pipes, and tighten the flange bolts again, some piping applications will require new gaskets to be installed.
What is the difference between blank flange and blind flange?
A blind flange dead ends the tubing flow; a blank flange is one that is to be machined to a finished product. Or,it is that can not see and the other has no facial expression.
How many types of blinds are there in oil and gas?
How do you change the position of a spectacle blind?
The position of a spectacle blind is changed by loosening the surrounding bolts of the piping system, rotating the plate, replacing any gaskets, and then reassembling and tightening the bolts. Spectacle blinds can commonly be found in a range of face types such as: Ring-Joint Blanks (used in conjunction with ring joint gaskets)
Which is the reference specification for spectacle blind?
Generally, flange factories are also spectacle blind manufacturers. The reference specification for pipeline isolation devices (including spectacle blind, ring spacers, and line blanks) is ASME B16.48.
How to tell if a spectacle Blind is open or closed?
It is easy to understand if a spectacle blind is in an open or closed position, as one of the two discs is always outside the pipe (so when the ring is visible, the pipeline is closed; when the solid disc is visible outside, the pipeline is open). For spades and ring spacers, holes on the hangers inform the staff.
What do I need to make a spectacle blind?
Spectacle Blinds should be made from a plate or forging specification, approved for use by ASME B31.3, of essentially the same chemical composition as the mating flanges and piping involved. Depending on a customer specification, some dimensions can be different from what on this page is defined.