Fixing Open-Area glitch in Tee Strainers

Tee Strainer

Tee Type strainers (T-strainers) are notorious for their low open area as compared to a Basket strainer or a Y-strainer.   The reason for this low open area is the screen construction style in a tee strainer. The screen is similar to a cylinder cut in to half along its length. In a basket strainer, the screen is more like a complete cylinder. Due to this screen structure, the open area or the filtration area in Tee strainer is significantly lower than a Basket or Y strainer.

So what do we do if the design team opts for a tee strainer over a basket strainer due to budget constraints and the process team still calls for an open area that is similar to a basket strainer?  I suggest two paths. Option one is to add an extension pipe between the neck of the equal tee and the cover flange. The length of the extension pipe can be increased or decreased based on the open area requirement. By adding and increasing the length of the extension pipe, we can increase the length of the screen that sits inside the equal tee. This increase in length of the screen will increase the open area or filtration area of the tee. Personally, I am not a fan of this approach, as this option will alter the outer dimension of the strainer housing. This can adversely affect the structural layout of the pipes especially in space-restricted services in an offshore platform or an FPSO.

The second option is to change the structure of the screen. Instead of having a simple half cylinder, we can construct the screen with pleated or zigzag screens. The number of pleats can be varied to increase the open area. This option does not alter the outer dimension of the strainer housing. Fabricating a pleated design screen needs a lot of expertise, however I still prefer this option. So there you go, open area for a tee strainer can be increased using any of the above two options.