Spectacle Blinds, Spades and Spacers

Spectacle Blinds, Spades and Spacers

Spectacle blinds, spades and spaces are a common feature of pipelines or piping in most industries as they are used to enable maintenance work.

They can be used to isolate a section of pipe or isolate a specific device so that it can be cleaned, checked and generally looked after. It is used as a semi-permanent or long-term isolation device and is considered to be a very safe method of doing so.

Spectacle blinds, spades and spaces are a cheap and robust alternative to valves. They can also be called line blinds, spacers and blanks, paddle blinds and spade blinds.

Usually, the material that a spectacle blinds, spades and space is made from matches the piping system that it is being placed into. Here at Special Piping Materials, we can supply them in a range of different exotic and specialist materials such as:

• Duplex
• Super Duplex
• Nickel Alloy
• Stainless Steel
• 6% Moly

Spectacle blinds

A spectacle blind is a steel plate cut into two discs of equal diameter and thickness. One disc is a solid plate while the other is a ring, whose inside diameter is equal to that of a flange. The two discs are connected by a small section of metal.

Spectacle blinds are usually used in piping systems where a particular section needs to be periodically separated or isolated from the rest for either maintenance or safety reasons. If it is positioned so the solid plate is in situ then liquid or gas is prevented from flowing through the pipe, whereas the ring plate allows the product to flow through.

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:

• Raised Face (for high-pressure applications)
• Flat face (for low-pressure applications)
• Ring-Joint Blanks (used in conjunction with ring joint gaskets)

Spades and Spacers

Spades and Spacers perform the same function as a spectacle blind – they are essentially a simplistic valve. They are fitted in a pipeline between two flanges and are bolted into place. They are chosen over spectacle blinds in some cases as spectacle blinds can be bulky.

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.

To change from one to the other, half the surrounding bolts need to be removed and the Spade or Spacer is swapped over. The bolts can then be reinstalled and tightened.

Each spade or spacer has a particular handle that is shaped in a way so that engineers or maintenance crews know whether a spade or spacer is installed in the pipeline. For smaller spades and spacers, it is common for the spacer to have a hole in the handle and the spade to have no hole.

Spades or spacers can commonly be found in a range of face types such as:

• Raised Face
• Flat face
• Ring-Joint sealing surface (used in conjunction with ring joint gaskets)

Manufacturing of spectacle blinds, spades and spacers

Spectacle blinds, spades and spacers can be manufactured in a variety of sizes, materials and pressure ratings.

When being manufactured they 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.

The diameter of the spectacle blinds, spades and spacers, is dependent on the flange size, and the thickness from the pressure class of a flange. The sealing surface then selected is usually conducted in accordance with the face finish from the flange.

The following details need to be specified when spectacle blinds, spades and spacers are being ordered:

• Nominal Pipe Diameter
• Pressure Rating
• Material of construction
• Dimensional Standard
• Facing Type

Applications of spectacle blinds, spades and spacers

Spectacle blind, spades and spacers are mainly used to provide flexibility during operation and maintenance. They can often be found in the following applications in a variety of industries such as Petrochemical, LNG, Desalination, Oil & Gas and Mining:

• At inlets and outlets of static and rotary equipment
• In bypass line
• At unit battery limit
• Where double isolation is required for high-pressure lines

Quality control

All the spectacle blinds, spades and spacers that Special Piping Materials sources and supplies can meet the requirements of the oil, gas, petrochemical, water treatment and other heavy industries.

Here is a full list of the spectacle blinds, spades and spacers that we stock, in a range different material:

• Super Duplex (both S32750/s and S32760)
• Duplex (S31803 and S32205)
• 6% Moly (S31254)
• Stainless Steels (316L, 304L, 904L, 310, 321, etc)

Our spectacle blinds, spades and spacers come in pressure ratings of:

• 150lbs
• 300lbs
• 600lbs
• 900lbs
• 1500lbs
• 2500lbs

Special Piping Materials’ spectacle blinds, spades and spacers are manufactured in accordance with the American Society for Testing & Materials (ASTM) Standard as follows:

• ASTM A182
• ASTM A240

The dimensional standard of the spectacle blinds, spades and spacers we supply are in accordance with the American National Standards Institute (ANSI):

• 48
• API 590

In stock in our warehouses around the world, we have the following sizes available:

• ½” (DN15) through to 24” (DN600)

*We can also quickly source and arrange delivery of sizes up to 72” (DN1800)

We understand that our client’s requirements can vary. As a result, as well as the standard size and specification mentioned above, we can also design and manufacture bespoke fittings to fit our clients’ specific drawings or project requirements.

Special Piping Materials and spectacle blinds, spades and spacers

Spectacle blinds, spades and spacers are key components of pipeline systems around the world and Special Piping Materials has been involved in the sourcing and supply of these items for many years.

We understand that the safety element of spectacle blinds, spades and spacers is incredibly important. We therefore assure that all products we supply are tested rigorously to each of our client’s specifications. Extra robust corrosion protection can be supplied upon request.

All our products are packaged according to an engineering or project specification. Short delivery times can be met where required.

Speak to our sales team today in one of our offices across the globe to order your next supply of spectacle blinds, spades and spacers.