Figure 1003 Misaligning Hammer Union — Standard Service

The Figure 1003 is a misaligning union for high-pressure water, oil, mud or gas service where the pipe will not line up.

Applications

High-pressure water, oil, mud or gas service where pipe alignment is a problem.

Construction and sealing

• Takes up to 7.5 degrees of misalignment off the centre line, 15 degrees included. The 2 in size is the exception, at 3.5 degrees off the centre line and 7 degrees included.
• Available as line pipe threaded or butt weld; the 5 in is butt weld only.
• O-ring seal that holds pressure at any position within the misalignment allowance, over steel-to-steel seating.
• Sealing: O-ring over steel-to-steel seating.

Working pressure

Our supplier rates the 2 in and 3 in at 10,000 psi (690 bar) cold working pressure and the 4 in and 5 in at 7,500 psi (517 bar).

Working pressure falls with size, and manufacturers do not agree on the Figure 1003 rating. The ratings below are our supplier's published figures; other manufacturers rate the same figure number lower in standard service. Work to the rating stamped on the union in front of you.

How a hammer union makes up

A hammer union is a three-piece connection. A male sub and a female sub carry the two line ends, and a wing nut turns on a thread cut into the male sub and pulls a shoulder on the female sub down onto the seat. The lugs standing proud of the nut are struck with a hammer to tighten it, which is where the name comes from — the joint is made up and broken out with a sledgehammer rather than a wrench, so a line can be rigged and stripped quickly in the field. The seal is made by the seat, not by the thread: the nut only supplies the load that holds the two seating faces together. That is why a union will leak from a scored seat or a perished seal long before the thread is at fault, and why a worn union is usually a sub or a seal replacement rather than a scrap part.

Specifying one

Four things fix a hammer union: the figure number, which sets the pressure class and decides what it will mate with; the service class, standard or sour gas; the end connection, threaded or butt weld; and the nominal size. Figure numbers are an industry series, so a union of the same figure and size from another maker will mate — but the pressure rating stamped on the union is what governs, not the figure number on its own. Send us the line specification and we will confirm the match before quoting.

Sizes and part numbers

Published in 2" to 5" with line pipe threaded and Sch XXS butt weld ends. Every orderable size, its weight, its dimensions and its working pressure are in the size table on this page. Where dimensions and weight are critical, ask us to confirm them against the build before you order.