A hammer union is a type of connection used in the oil and gas industry to join two or more pipes or components together in a temporary or permanent manner. It is designed to provide a reliable and leak-proof connection that can withstand high pressures and harsh operating conditions commonly encountered in oilfield operations. The name "hammer union" comes from the method used to assemble and disassemble the connection. A sledgehammer is typically used to tighten or loosen the union by striking the nut or lug on the connection. This allows for quick and secure make-up or break-out of the union without requiring specialized tools. Hammer unions consist of three main components: Male Sub: The male sub is the threaded component that is attached to one end of a pipe or equipment. It has external threads that correspond to the internal threads of the female sub. Female Sub: The female sub is the counterpart to the male sub and has internal threads that match the external threads of the male sub. It is typically connected to another pipe or equipment. Nut: The nut is a large, hexagonal component that is used to secure and tighten the male and female subs together. It is struck with a hammer to make or break the connection. Hammer unions are available in various sizes, pressure ratings, and configurations to accommodate different applications and operating conditions. They are commonly used in drilling rigs, wellheads, manifolds, and other oilfield equipment where frequent assembly and disassembly are required. The design of hammer unions allows for flexibility and rotation, making them suitable for applications where movement or misalignment may occur. They provide a robust and reliable connection that can withstand high pressures, vibrations, and the challenging environments encountered in the oil and gas industry.