Figure 1004 Hammer Union — Butt Weld, Standard Service, 10,000 psi

The Figure 1004 is a 5 in and 6 in butt weld union that carries the lip-type elastomer seals used in the smaller unions instead of the O-ring the 5 in and 6 in Figure 1002 uses.

Applications

High-pressure lines at 5 in and 6 in where a Figure 1002 O-ring union is difficult to make up square.

Construction and sealing

• Lip-type elastomer seals, in place of the O-ring used by the 5 in and 6 in Figure 1002. An O-ring union of that size has to be made up perfectly square or it gives trouble; the lip seal is what the Figure 1004 exists to fix.
• Butt weld ends, 5 in and 6 in.
• Available in standard service or sour gas trim.
• Sealing: Lip-type elastomer seal.

Working pressure

10,000 psi (690 bar) cold working pressure.

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 5" to 6" with 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.