Product category:
Hydraulic Components
News Release from: Lee Products | Subject: AFO plugs
Edited by the Engineeringtalk Editorial
Team on 19 June 2002
Axial force only for compact boss plug
The need for a leak-tight, metal-to-metal seal in high-pressure high-temperature manifold applications is an ideal situation for Lee Products AFO plugs (axial force only).
The need for a leak-tight, metal-to-metal seal in high-pressure high-temperature manifold applications is an ideal situation for Lee Products AFO plugs (axial force only) AFO plugs, which are designed to be both removable and reusable, feature a floating seal that self-aligns to allow for threaded holes that are not concentric with the through hole
This article was originally published on Engineeringtalk on 29 Jun 2004 at 8.00am (UK)
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Plugs seal in tricky situations
Lee Products has developed a range of AFO plugs (axial force only) that are both removable, reusable and are ideal for high-pressure/high-temperature situations.
Venting plug takes O-ring onboard
A new version of the AFO (axial force only) plug incorporates an O-ring for additional sealing in special oil tool applications.
As a result of the plug's two-piece construction, the seal does not rotate during installation, thus preventing galling of the seat.
Also, as all the force is contained in the axial direction, the boss diameter can be smaller compared to other designs of plug.
Standard AFO plugs are manufactured from corrosion resistant 303 and 15-5 stainless steel and do not require O-rings or sealants.
They are designed to withstand pressures up to 60,000lb/in2 and temperatures to 600F when fitted into hard materials as well as in softer materials, such as aluminium or plastic.
The plugs are available in sizes from 0.190 to 0.750in with UNF threads, however, depending on specific application requirements, special versions can be supplied.
For example, to meet NACE standards required in the oil industry A.F.O.
plugs have recently been supplied in Monel in sizes up to 1.325in UNF threads.
These special plugs were required to withstand 15,000lb/in2 working pressure and 22,500lb/in2 proof pressure.
Current API specifications dictate that plugging devices must provide both primary and secondary seal.
The AFO plug itself is considered to be the primary seal and because they are welded in position, the welding process satisfies the secondary seal requirement.
Whilst the oil industry has traditionally used NPT plugs, achieving a leak-tight seal with these types of plugs can prove difficult, particularly as PTFE tape is no longer permitted.
If the NPT plugs do not seal first time, the thread often has to be recut due to the distortion caused by the tapered thread on the NPT plug.
Typical offshore oil industry applications for A.F.O.
plugs include subsea wellhead trees, tubing hangers, completion tools, slick joints and down hole tools. Request a free brochure from Lee Products ...
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