Pipeline strainers for steam, condensate and liquids · Y-type vs basket, installation orientation, perforated vs mesh screens and the particle that passes, free area and pressure drop, screen material
A strainer is a screen in a pressure-rated body that stops pipeline debris — scale, rust, jointing compound, weld metal — before it reaches traps, valves, meters or process equipment. Settle three things before ordering: the body type and how it will be installed, the screen type and opening that set what passes and the pressure drop, and the body and screen materials and accessories such as blowdown, drain or magnetic inserts.
Y-type, basket (pot), straight and angle strainers, duplex basket strainers and self-cleaning strainers for steam, condensate, water and process liquids. Sintered and cartridge filters for clean steam, compressed-air filters and suction strainers for pumps sold with the pump are outside this page.
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01
Spirax Sarco's tutorial on strainers says they arrest pipeline debris such as scale, rust, jointing compound and weld metal to protect equipment, and classifies them by body as Y-type or basket type. It describes the Y-type as the standard choice for steam: a compact, strong cylindrical body that is in effect a pressure vessel, with some Y-type strainers able to handle up to 400 bar g, where high steam temperatures may call for chrome-molybdenum steel. Size for size, it says Y-type strainers hold less dirt than basket strainers and need more frequent cleaning. [1]
For installation it advises that in horizontal steam or gas lines the Y-strainer pocket lies in the horizontal plane, so water does not collect and get carried over; in liquid lines the pocket points vertically downwards so debris is not drawn back upstream at low flow. Strainers can be installed in vertical lines only with downward flow. Straight and angle types work similarly. [1]
Basket (pot) strainers have a larger vertical chamber, more free straining area and lower pressure drop than a Y-type of the same size, must be installed in horizontal lines with the base supported for large units, and for steam have a drain that can be fitted with a steam trap. Duplex basket strainers let flow be switched to a second unit so one can be cleaned while the system runs. [1]
Give the supplier the fluid (steam, condensate, water, oil, chemical), pressure and temperature rating, line size and end connections, flow rate and allowable pressure drop, body type, installation orientation, screen type and opening or mesh, body and screen materials, blowdown valve, drain or magnetic insert, duplex or self-cleaning option, certificates and quantity.
02
The tutorial describes perforated screens, made by punching holes in sheet and rolling it into a tube, with holes from about 0.8 to 3.2 mm for general debris, and mesh screens of fine wire layered over a perforated support, with holes as small as 0.07 mm. Mesh is the number of openings per linear inch, and the manufacturer states the corresponding hole size; the largest particle that can pass a square hole is found from its diagonal. [1]
It defines free area as the proportion of hole area to total screening area, which sets flow capacity: a larger free area and coarser screen give higher capacity and lower pressure drop, and a larger screening area reduces the blowdown frequency. Pressure drop can be found from the strainer's Kv value or a pressure-loss diagram. It names austenitic stainless steel for steam screens and monel for specialised chemicals or offshore service, and describes magnetic inserts for fine iron particles and self-cleaning strainers using scrapers, brushes or backwash. [1]
For clean steam — direct injection into product, sterilisation in pharmaceutical plants, humidification — it says strainers are not suitable and a filter with a sintered stainless steel element is needed, with a separator and a Y-strainer fitted upstream. [1]
Editorial calculation: the tutorial's example of a 200 mesh screen with a stated 0.076 mm hole gives a diagonal of 0.076 × √2 ≈ 0.107 mm, the largest particle that can pass. [1]
03
Titan Flow Control's YS12-CI Y-strainer data shows how a body rating is stated: cast iron to ASTM A126 Grade B, threaded ends, ASME Class 250, sizes 1/4 to 3 in, rated 400 psi WOG (non-shock) at 150 °F. Its pressure-drop calculator offers perforated screens of 1/32, 1/8 and 5/32 in and mesh-lined screens from 10 to 200 mesh, as well as 5, 10 and 25 micron linings. [2]
Titan's DS696-CS duplex strainer, for lines that cannot be shut down while a basket is cleaned, has a carbon steel body to ASTM A216 Grade WCB, raised-face flanged ends, ASME Class 150, sizes 6 to 8 in and a rating of 285 psi WOG (non-shock) at 100 °F, with a quad-ball diverter to switch between baskets. [3]
Editorial calculation: 1/32 in perforation is about 0.79 mm and 5/32 in about 3.97 mm; the 1/32 in hole sits at the fine end of the 0.8–3.2 mm range Spirax Sarco gives for perforated screens, and finer duty calls for a mesh-lined screen. [2] [1]
04
For US-flag vessels, the Coast Guard's marine engineering rules in 46 CFR Part 56 treat strainers as "fluid conditioner" fittings that form part of the pressure barrier (§ 56.07-5), and Table 2 of § 56.60-1 lists two strainer specifications: ASTM F1199 for cast and welded pipe line strainers (150 psig and 150 °F maximum) and ASTM F1200 for fabricated (welded) pipe line strainers above 150 psig and 150 °F. The same part sets open-area and duplex-cleaning duties that a strainer order for ship service has to meet. [4]
Editorial calculation: for an assumed bilge suction pipe of 50.8 mm (2 in) bore, the pipe area is π × 25.4² ≈ 2,027 mm², so the strainer needs at least about 6,080 mm² of open area; with a screen of 40% free area that means roughly 15,200 mm² of gross screen area. The 40% figure is an assumption; use the free area the strainer maker states for the screen quoted. [4]
| Service | 46 CFR Part 56 requirement | What it means for the strainer order |
|---|---|---|
| Bilge suctions (§ 56.50-50(g)) | Each individual bilge suction fitted with a strainer having an open area of not less than three times that of the suction pipe; a mud box or basket strainer in an accessible position between the bilge suction manifold and the pump. [4] | State the suction pipe bore and ask for the screen open area. [4] |
| Burner fuel-oil service (§ 56.50-65) | Suction and discharge strainers capable of being cleaned without interrupting the oil supply; located or shielded so oil cannot spray on the burner or boiler casing. [4] | A duplex (twin-basket) strainer or two strainers with changeover valves. [4] [3] |
| Gasoline fuel systems (§ 56.50-70(d)) | A suitable twin strainer in the fuel supply line in the engine compartment, with a drip pan under it. [4] | Twin strainer plus drip pan. [4] |
| Oil piping systems (§ 56.50-60(k)) | Strainers subject to normal oil leakage fitted with drip pans or other means to keep oil out of the bilge. [4] | Drip pan or tray. [4] |
| Material specification (§ 56.60-1, Table 2) | ASTM F1199 (150 psig/150 °F maximum) or ASTM F1200 (above 150 psig and 150 °F). [4] | Specification the body is made to. [4] |
05
The companies in the manufacturer list below show this product on their own websites. Confirm the legal seller, factory and scope for your order.
Ask any supplier for the Kv value, screen hole size and free area, and the body pressure–temperature rating for the size quoted. [1]
06
This is a functional reference built from the sources cited; it is not one maker's specification.
| Part | What it controls | Fix in the order |
|---|---|---|
| Body | Pressure rating; dirt capacity. [1] | Y or basket; rating. |
| Screen | What passes; pressure drop. [1] | Perforated or mesh; hole. |
| Screen support | Holds fine mesh. [1] | Perforated cage. |
| Blowdown or drain | Cleaning; condensate. [1] | Valve; trap. |
| Magnetic insert | Fine iron particles. [1] | Option. |
| Self-cleaning mechanism | On-line cleaning. [1] | Scraper or backwash. |
07
A strainer quotation needs values for your line. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Nominal Diameter | Line size. | DN. |
| Operating Pressure | Y-types to 400 bar g exist. [1] | PN/class rating. |
| Operating Temperature | High-pressure steam needs alloy bodies. [1] | Rating. |
| Mesh Size | 0.8–3.2 mm perforated; mesh to 0.07 mm. [1] | Hole size; mesh. |
| Flow Coefficient | Kv for pressure drop. [1] | Kvs. |
| Body Material | Chrome-molybdenum steel for high-temperature steam. [1] | Grade. |
| Screen Material | Austenitic stainless; monel. [1] | Grade. |
| Connection Type | Flanged, screwed, welded. | Type; standard. |
| Weight | Support needs. [1] | kg. |
08
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Fluid: [steam; condensate; liquid] Rating: [pressure; temperature] Line: [DN; connections] Flow: [rate; max Δp] Body: [Y; basket; duplex; self-cleaning] Screen: [perforated/mesh; hole size; material] Accessories: [blowdown; drain; magnet] Quantity: [units]
These companies list this product on their own websites.
Its website lists Y-type strainers.
Product scope checked 2026-10-12
Its website lists Y-pattern, basket and DIN strainers.
Product scope checked 2026-10-12
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Spirax Sarco says down for liquid lines, but horizontal in steam or gas lines so water does not collect. [1]
Where more dirt-holding capacity and lower pressure drop are needed; baskets go in horizontal lines and can be duplexed. [1]
Mesh screens can have holes as small as 0.07 mm; perforated screens run from about 0.8 to 3.2 mm. [1]
No; Spirax Sarco says a sintered stainless filter is needed, with a separator and strainer upstream. [1]
State body material and ASME class: Titan's cast iron YS12-CI is Class 250 at 400 psi WOG (150 °F); its carbon steel DS696-CS duplex is Class 150 at 285 psi WOG (100 °F). [2] [3]
46 CFR 56.50-50(g) requires an open area of not less than three times that of the suction pipe, plus a mud box or basket strainer between the bilge manifold and the pump. [4]
Sources checked 2026-10-12. Spirax Sarco's Learn About Steam tutorial covers strainer types, screens, sizing and installation. The US Coast Guard's 46 CFR Part 56 sets strainer duties for ship piping; Titan Flow Control's product pages give body ratings.
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