The 90-degree elbow, a malleable cast iron pipe fitting, is one of the most fundamental and critical connectors for achieving right-angle turns in piping systems. Its name directly reveals its function: “90 degrees” refers to the angle of the turn it creates, while “elbow” defines its role in changing direction within the pipeline. Through its sturdy, right-angled cavity, it guides fluids or gases smoothly through a quarter-circle (90°), making it an indispensable component in building complex piping networks.
In terms of structure and connection method, the 90-degree elbow exhibits a typical “L” shape. Both ends are machined with standard pipe threads, which are primarily categorized into two types depending on the application scenario: the British 55° sealing pipe thread is prevalent in the Chinese and Commonwealth markets, while the American 60° tapered pipe thread is common in North America or in designs that adhere to American standards. During installation, construction workers machine external threads on the ends of the two pipes to be connected, then screw them onto the internal threads on both ends of the elbow. Tape or sealant is then applied to the threads to ensure a secure and airtight connection, ultimately creating a compact and reliable right-angle passage.
When selecting an elbow, consider the following key characteristics:
1. Diameter and Reducer: The most common elbow is a constant-diameter elbow, meaning both ends have the same diameter. Reducing elbows also exist, with different diameters at each end, allowing for pipe diameter conversion while changing direction.
2. Center-to-End Distance: This is the core parameter for measuring elbow size, measuring the straight-line distance from the center of the elbow to the end of either end. This dimension directly determines the space it occupies during installation and is crucial for piping layouts in confined spaces.
3. Material and Corrosion Resistance: Made of malleable cast iron (also known as wrought iron), 90-degree elbows offer excellent strength and toughness. Surface treatment options typically include galvanizing (silver-white, excellent corrosion resistance, suitable for humid, outdoor environments), black galvanizing (original casting color, low-cost, suitable for dry, non-corrosive environments), and varnishing (coated with anti-rust paint, with intermediate corrosion resistance). Users should select the right elbow based on the corrosiveness of the medium and environmental conditions.
90-degree elbows are widely used in nearly all metal pipe applications using threaded connections. In the construction industry, it’s commonly found at the junctions between risers and lateral branches in indoor water supply and fire sprinkler systems. In the industrial sector, it’s also frequently used at the pipe interfaces of various equipment and instruments to adapt to spatial layouts.
In short, malleable cast iron 90-degree elbows, with their simple structure, reliable connection, and comprehensive specifications, have become the preferred solution for achieving right-angle turns in piping projects. Their proper selection and installation are crucial for ensuring smooth, sealed, and long-term stable operation of the entire piping system.
Post time: Oct-09-2025