10 replies to this topic

[thelasik]

I would appreciate it if someone could define the uses or give a description of the following fittings:

-Blind
-Spacer
-Flange
-Spool piece

Any help is much appreciated. Thanks!

[djack77494]

thelasik,

These are very basic terms. I suggest you obtain a book of piping design and review it. There are no doubt other fundamental aspects of this important subject that you would pick up from such a reference. As to my homemade definitions for your questions,

Flange: A disk-shaped piece of steel that is installed perpendicular to the flow in a pipe. Always there are two flanges that mate. There are bolt holes around the perimeter of the flange and a gasket between the flanges. Flanges are used as connectors; they connect two sections of pipe or a pipe with some other fitting.

Blind: Short for blind flange. A solid disk that terminates a section of pipe.

Spacer: A short hollow cylindrical section of metal that is located between two flanges. Spacers are often changed out with other fittings such as a blind flange as operational needs change.

Spool piece: A section of piping with flanges at both ends. Typically spool pieces are installed to permit easy removal for access or for operational changes.

Hope I've answered your questions, and please, get your hands on a good piping reference book. Here pictures are worth a thousand words.

[luuquocdai]

<b>Dear Thelasik
Here is information and description for you.
- Spacer</b>
<img src="http://i51.photobuck...s/DSC_0085.jpg" border="0" class="linked-image" />

<img src="http://i51.photobuck...s/DSC_0086.jpg" border="0" class="linked-image" />

<img src="http://i51.photobuck...s/DSC_0087.jpg" border="0" class="linked-image" />

<img src="http://i51.photobuck.../DSC_0x042.jpg" border="0" class="linked-image" />
<b>
</b>- Flange
<img src="http://i51.photobuck...s/DSC_0010.jpg" border="0" class="linked-image" />

<b>I will continue in near future, because I don't have enough time to upload all pictures.
Best regards.
</b>

[thelasik]

Thanks for the help!

[bgw2]

In Pipefitter terminology:

• A blind is a metal plate inserted in a Flanged connection for the purpose of preventing flow or release;
• A spacer is a metal ring inserted in a Flanged connection to maintain spacing needed for future installation of a blind;
• A Flange is a fitting which allows for two fittings or pieces of pipe to be bolted together;
• A spool piece is usually a prefabbed section of pipe most commonly one which is flanged for bolting but may be for welding in place.

more terminology available @ www.pipefittersplus.com

[djack77494]

I realized a lack in my own pipefitting terminology education. Can someone tell me the difference, if any, between a spade and a blind flange. I didn't find that in the suggested link. Thank you.

Edited by djack77494, 24 June 2010 - 07:28 AM.

[Art Montemayor]

Doug:

From my British West Indies experience of 50 years ago, I recognize the term "Blanking Spade" - which is nothing more than a "blind" in the USA. It is the blind part of a spectacle blind. Spectacle blinds are a more permanent form of blanking spades.

We don't use the term in the USA because we have our own terms. It is, to my knowledge, stictly a Brit term.

[djack77494]

Thanks, Art.

[katmar]

djack77494 and Art - I was not aware that there were regional differences in this terminology. I learn something new every day. Here in South Africa we use the terms "spectacle blind" or "spade" to refer to a flat plate (like a RO without the hole!) that is slipped between flanges to prevent flow. It would usually not have bolt holes and would sit inside the bolt circle - although a spectacle blind would have one hole to allow rotation to the unrestricted half. When we speak of a blind flange we would mean a full thickness flange to the applicable spec that bolts on to the end of a flanged spool or nozzle.

A spade should of course be made thick enough to withstand the system pressure, but I'm afraid in my experience it often happens that someone grabs the nearest piece of 3mm or 6mm plate and flame cuts a spade that later looks more like a wok than a plate.

[Art Montemayor]

Katmar:

My experience has been that the terms “spade” and “blind” are one and the same – exactly as you describe them: a flat, circular plate that has a handle and is slipped between flanges to block flow either provisionally or permanently.

However, the term “spectacle blind” is one I have found to be common between Americans and other Anglophones. When I wrote “spectacle blinds are a more permanent form of blanking spades”, I meant to state that both of the pieces required for the mechanical design of a blind (or spade) application are made as ONE piece where the round, annular metallic spacer (required to replace the blind when the latter is not required and the line is put into full flow) is welded or joined to the side of the spectacle so that the assembly can be used to either block flow or allow it. This type of mechanical assembly allows the operator to visually determine when the line is blocked or when it is in full flow with ease – especially when the application is in an overhead pipe rack that is difficult to access and investigate. Another feature that this assembly permits is that it keeps both mated pieces permanently together – something that both Operations and Maintenance personnel prefer because trying to keep a set of two matched pipe components together for the occasion when they will be needed (such as a shutdown) often creates chaos and problems because either one of the pieces is often lost, misplaced, or simply thrown away in the bone yard after its use. The spectacle blind actually looks just like a pair of spectacles – except that one of the “lens” is “blind”.

A spade (or blind) has been used instead of a spectacle blind – in my experience – primarily because it allows for quick installation in the larger pipe sizes – i.e., 10” and higher – where the size and weight of the required spectacle would be excessive and bulky. Additionally, I would add another experience involving blinds and spectacles that I picked up in DuPont plants: ALWAYS CALCULATE AND DOCUMENT THE THICKNESS OF SUCH ITEMS AND MAKE SURE THAT THE CORRECT AND PROPER MAXIMUM ALLOWABLE LINE PRESSURE DIFFERENCE IS CLEARLY PEENED ON THE METAL HANDLE IN ORDER TO ALLOW MAINTENANCE, OPERATIONS, AND INSPECTIONS CREWS TO BE FULLY AWARE THAT THE ABSOLUTELY CORRECT METAL THICKNESS HAS BEEN APPLIED FOR THE MAXIMUM PRESSURE DIFFERENCE EXPECTED IN THE LINE BEING BLOCKED. I cannot stress this safety point enough. I hate to say it, but there are many operating and maintenance personnel that have avoided this recommendation and have paid a dreadful price. I make mention of this experience for the sake of those reading this thread – expecially recent young graduates.

[riven]

Re spade and spectacle blind

http://www.crp.co.uk...ng.aspx?page=56

So Art is correct. These terms I have only seen in the UK (I have not seen their use in Ireland, 3 countries mainland Europe)

Edited by riven, 28 June 2010 - 03:40 AM.