Strainers are closed vessels that collect solid particles to be separated while passing a fluid through a removable screen. The screens can collect particles down to 0.001 inch in diameter. They can remove more than unwanted material. They can also remove wanted materials that can be used elsewhere or in other processes. You can find strainers upstream of sensitive equipment such as meters, pumps, compressors, traps, valves and filters. Strainers and filters are basically the same thing. The difference is that a filter removes much smaller particles, particles you normally can't see. If you can not see the material being removed, it is usually called a filter.
You can find strainers in almost every industry: chemical, food, water, petroleum, paint and ect. Strainers come in different configurations such as Y Strainers, Simplex Strainers, Duplex Strainers and Temporary Strainers. They can be bolted, threads or welded in line.
Basket strainers come in two types, single and double. A simplex strainer (single basket) is used when the flow or process can be shut down for a short period of time.
A duplex strainer (double basket) is used when the flow or process can not be shut down and must continue to flow. The duplex allows you to shut one basket for cleaning while the other is still in operation. The screen is in the shape of a basket and removed from the top and the strainer. These are normally used where larger amounts of trash/solids need to be removed. They can come with a blow-off connection for manual or automatic cleaning.
Basket strainers come in two types, single and double. A simplex strainer (single basket) is used when the flow or process can be shut down for a short period of time. A duplex strainer (double basket) is used when the flow or process can not be shut down and must continue to flow. The duplex allows you to shut one basket for cleaning while the other is still in operation. The screen is in the shape of a basket and removed from the top and the strainer. These are normally used where larger amounts of trash/solids need to be removed. They can come with a blow-off connection for manual or automatic cleaning.
Their are three types of temporary strainers, cone, truncated cone, and flat. They are normally used during the initial startup of a new application such as a pump. It is inserted between two flanges in the pipeline up stream of the equipment to be protected. After startup and the debris has been collected by the strainer, it is usually removed. There is little pressure drop when the screen is clean since it is in a straight flow with the pipe. The bottom of the screen cone is to be down stream.
There are two types of strainers, basket and y. The y strainer is normally used where there is a small amount of material to be collected. This strainer can be installed in the horizontal or vertical position. The basket must be to the bottom of the pipe or facing the down flow direction to collect the particles. A y strainer can come with a blow-off connection for automatic cleaning. With liquids y strainers have a greater pressure drop than basket strainers because of their size (comparing same sizes). But with gases a y strainer has a relatively low pressure drop.
| Mesh Size | Particle Diameter
(meter x 10-6) |
|---|---|
| 4 | 5,205 |
| 8 | 2,487 |
| 10 | 1,923 |
| 14 | 1,307 |
| 18 | 1,000 |
| 20 | 840 |
| 25 | 710 |
| 30 | 590 |
| 35 | 500 |
| 40 | 420 |
| 45 | 350 |
| 50 | 297 |
| 60 | 250 |
| 70 | 210 |
| 80 | 177 |
| 100 | 149 |
| 120 | 125 |
| 140 | 105 |
| 170 | 88 |
| 200 | 74 |
| 230 | 62 |
| 270 | 53 |