It has been proven that strainers are very useful in protecting downstream equipment in a pipeline such as pumps, valves, steam traps, turbines, meters, and other elements, from the detrimental effects of foreign particles and unwanted debris. In particular, vertical piping that’s found at pump inlets requires the use of a Y type strainer. Two things that must be given special attention to in a strainer are the orientation of the debris collection chamber and the blowdown connection. The device must be installed in a way that it’s placed at the lowest position possible. As such, a Y type strainer must be installed with its screen facing downward to effectively trap the debris in the collection chamber.
Another important factor to determine in designing a Y type strainer is the kind of end connections that’s most suitable. There are three common types to choose from as discussed in details below.
- Threaded - this type is typically a tapered female pipe thread. There are male end connections available as well.
- Flanged - the industry standard flange rating Classes range from Class 25 through to Class 2500. Other options such as ring type joints and tongue groove joints are also available.
- Weld ends - the standard 37.5° beveled end is commonly used, but butt weld ends come in all sizes with various forms of end preparations. In purchasing Y type strainer with this end, it’s crucial to specify the accurate bore of the pipe for the manufacturer to provide a matching bore in the strainer.
Most types of small strainers, particularly the Y type strainer, are engineered according to fitting standards to match full pressure ratings and subjected to lower temperatures and higher pressures. Thus, at the initial design it is very important to determine working pressure and temperature, flange rating, corrosion allowance, and any operating conditions that can affect vessel loading.