Strainers are very critical components of piping systems because they protect equipment from potential harm caused by dirt and other particles carried by the process fluid.
As the market grows more competitive, there is greater attention on decreasing plant downtime and maintenance. Pipeline debris such as scale, rust, jointing compound, weld metal, and other substances that may make their way into the pipeline system regularly cause plant damage in steam and condensate systems. Strainers are devices that stop these solids from moving liquids or gases and safeguard equipment from their damaging effects, saving downtime and maintenance. And thus, using the proper strainers at the correct places is important for protecting expensive and critical downstream equipment such as pumps, flow meters, steam traps, control valves, and so on.
Strainers may be installed before the pumps during system start-up and flushing to safeguard them from construction waste that may have been left in the line. Permanent strainers can be put ahead of control valves, traps, and instruments to safeguard them from corrosive compounds that get dislodged and spread throughout the pipe system.
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What is a Piping Strainer?
Pipe strainers are essential parts of pipe systems because they protect expensive equipment from foreign particles carried by the process fluid. Piping strainers are often named as Strainer Filters.
A strainer valve is a pipe fitting that allows fluids to pass through for purification, filtration, or separation from solid materials; anything that strains a liquid; and any device that functions as a screen or filter to keep solid bodies from getting mixed in a liquid stream or flow line. Strainers prevent pipeline debris like scale, rust, construction residues, and weld metal from harming equipment including condensers, cooling systems, pumps, compressors, meters, spray nozzles, generators, and steam traps, resulting in less downtime and less maintenance.
Working: Piping Strainer.
The pipeline strainer operates on a pretty basic concept. It makes no difference whether you’re using a tee, a plain duplex, or a Y-trainer. You must be able to locate both the input and the outflow. The fluid flows through the filter housing into the suction section after the strainer is fully engaged. When fluid runs through the strainer, it captures and holds all foreign elements in place. This can contain seaweed, plastics, large particles, and all such impurities. Foreign particles are effectively blocked by strainers that work properly.
The hole of the rotary ball is usually of the same diameter as the pipe, although it can be smaller. The valve can be turned using the operating handle on the valve stem, which is attached to the ball.
Types: Piping Strainer.
There are two main categories of classification for piping strainers:
- Permanent Strainers: These strainers have different types depending on their construction design.
- Y-Type Strainer: They are low-cost strainers that are utilized in high-pressure lines with a low concentration of dirt or foreign particles. They can be mounted in both horizontal or vertical lines, with the filtering element pointing down.
- Basket Type Strainer (Simplex and duplex): Basket strainers are commonly used because they have a great ability to hold foreign particles. Basket strainers are only utilized in horizontal lines, and they are usually employed for liquid services with high flow capacity.
- Temporary Strainers: Strainer valve manufacturers generally prescribe the use of these strainers to safeguard the system components from construction and fabrication debris. These strainers are used at the time of system start-up just after the fabrication work is finished and the system is ready to be tested. These are used for a small period of time. Some common designs used are:
- Cone type strainer
- Truncated cone type strainer
Construction: Piping Strainer.
Different types of construction materials are been used by strainer valve manufacturers depending on the strainer’s application.
- Cast iron: Because of its lower construction cost, it is the most commonly used strainer body material. It’s employed in systems where the water pressure and temperature aren’t too high, and the system isn’t subjected to a lot of thermal or mechanical stress. Cast iron is primarily utilized for bigger diameter potable water lines and numerous non-potable water systems, as well as a range of other product and process applications.
- Bronze is the material of choice for brackish, saline, and seawater service. It is frequently utilized to provide potable water supplies. It costs twice as much as cast iron.
- Carbon steel is employed where high temperatures and pressures are observed, as well as resistance to thermal and mechanical shocks. Where there is a risk of fire, carbon steel components are the preferred material.
- Stainless Steel: Because of its protection against corrosion and contamination, as well as its ease of maintenance, stainless steel is the ideal material for the body, basket, and screen.
Screens and Filters: There are two different types of screens that are used in strainers.
- Perforated Screen: Multiple punches are used to punch a high number of holes in a flat sheet of the appropriate material to make perforated screens or strainers. The hole sizes generally vary from 0.8 mm to 3.2 mm on these screens, which are relatively coarse.
- Mesh Screen: Fine wire is woven into a grid or mesh pattern. This is then usually laid atop a perforated screen, which serves as a mesh support cage.
Selection Criteria: Piping Strainer.
The effectiveness of a piping strainer depends on the proper selection of a strainer according to the application. Some parameters that are to be kept in mind before selecting a strainer are:
- Flow Rate: For a higher flow rate of a system, Basket strainers are to be used.
- Quality of fluid: If a fluid tends to have a higher number of foreign particles, then the use of a Basket strainer is prescribed as it has a higher dirt holding capacity.
- Application Requirements: If the system allows frequent cleaning of strainers, then Y-strainer can be used otherwise for long-term use duplex basket strainers are suitable.
- Orientation: If you need to use a strainer in a vertical position then a strainer valve manufacturer will prescribe a Y-type strainer.
- Pressure loss: Basket strainers have less pressure loss than Y-strainers. That is why, when there is a doubt, a basket strainer can be easily installed. It will be more expensive, but it will satisfy all of your needs.
Installation: Piping Strainer.
Ensure that all machined surfaces do not have any defects and that the inside of the strainer is clear of foreign items. All strainers should be placed with the strainer body’s arrow facing in the flow direction. Threaded strainers should be installed with a suitable sealant on the threads. The flanged bolting on flanged strainers should be fastened carefully in a clockwise rotation till all the bolts are tight. The system may now be gradually pressured while being checked for leaks around all connections. If there is a leak, depressurize the system and repeat the installation process.
Temporary strainers are used to safeguard equipment and instruments while they are being set up. After the installation of a new plant, the strainer is normally positioned between a pair of flanges for some time initially. For the convenience of installation or removal, a spool piece equal to or greater than the length of the strainer is advised. Conical strainers, basket strainers, and plate strainers are the three major types of temporary strainers.
Maintenance Guide: Piping Strainer.
- To clean a Y-strainer screen, remove the plug from the bushing, cap, or bolted cover, allowing the strainer to drain the loose material inside the screen. If the strainer is attached to a blow-off valve, it can be opened to clean as well. The screen element of the Y-strainer can also be cleaned by removing the bushing, cap, or cover.
- Remove the cap or cover and pull off the basket screen for service on basket strainers with a closed bottom basket. The blow-off plug may be removed if the strainer screen is bottomless, and then it can be drained and cleaned like a Y-strainer.
- Cleaning screens should be done with caution. After removing a screen, soak it in a cleaning solution or scrub it clean with a brush. Allowing trapped material to solidify in the screen will make it harder to remove. Screens should be cleaned on a regular basis to avoid becoming clogged.
- Pressure loss due to clogging will be shown by a pressure gauge mounted before and after the strainer. This can aid in the creation of a cleaning plan for the strainer screen. Extra screens might help keep the system running while it is being cleaned.
Note: Before removing or loosening any bushing, cap, plug, or cover on a strainer, take extra care to verify there is no pressure in the system. The strainer should be emptied for service only after the system has been depressurized. The usage of a pressured Strainer can result in significant injury and/or property damage.
Filter Vs Strainer
Every strainer is a filter, but not every filter is a strainer. A filter is a piece of equipment that separates particles from a liquid or gas. It comes with a disposable medium for eliminating micron-sized particles. Filters come in a variety of shapes and sizes, and a strainer is only one of them. A strainer removes bigger particles from a process stream using a perforated plate or screen mesh. The main benefit of a Strainer is that it can be reused. When the filter’s screen becomes clogged, it must be replaced.
- In the case of a strainer, the key difference appears to be the diameter of the pores in the media screen, commonly known as mesh size. There are filters that can remove particles as tiny as 1 µ
- Resistance is another element of differentiation. Strainers have a low threshold to liquid flow in mostly. When compared to the pressure drop over thick media filters or membrane filters, the strainers have a minimal pressure drop.
- A strainer is used to prevent unwanted material from damaging downstream equipment (such as pumps and instruments). A filter is used to remove particles from system fluid.
Application: Piping Strainer.
Strainers should be positioned upstream of pumps, loading valves, control valves, meters, steam traps, turbines, compressors, solenoid valves, nozzles, pressure regulators, burners, unit heaters, and other attached critical devices to prevent unexpected shutdown due to clogging. The most typical particle retention range for strainers is 1 inch to 40 microns.
To summarise, this is everything that is there to know about strainer valves and their different types. If you wish to share your experience with us, please leave a comment. Is there anything more you’d want to know on the subject? Please do not hesitate to contact us, as our professionals are ready to provide you with the professional help you require.