Attribute Schema Library
Attribute schemapump, valve & process equipment

Strainers Attributes (Y, Basket, Duplex, T-Type)

A strainer holds a perforated or mesh-lined element in the flow path to catch scale, weld slag, and debris before it reaches a pump, meter, control valve, or steam trap. Distributors sell them next to the equipment they protect: Y-strainers and simplex baskets off the shelf, duplex and fabricated units against a spec.

The data is hard for two reasons. First, variant explosion. One Y-strainer series runs 1/4 in through 12 in, in bronze, cast iron, carbon steel, and CF8M, with threaded, socket-weld, flanged, grooved, and solvent-socket ends, each in six perforation sizes. Manufacturers publish that as a table in a PDF, not as rows — so catalogs carry one record per series and lose the screen.

Second, the screen is the product and it is the worst-documented field on the page. Suppliers put perforation size and mesh count in one column, so "20" can mean 20 mesh or 0.020 in perf. Ratings drift the same way: "150#" is ASME B16.5 Class 150 on a steel body and ASME B16.1 Class 125 on an iron one.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Strainer Type
enum
Y-strainer (wye)

Sets cleaning method, footprint, and whether flow continues during service. A duplex and a Y-strainer are not substitutes at the same size.

Nominal Size (NPS / DN)
enum · in / DN
2 in (DN50)

First filter every buyer touches. Strainers are sized to the line, not to the flow, so this must match the pipe exactly.

End Connection
enum
Flanged, ASME B16.5 Class 150 RF

Threaded, socket weld, butt weld, flanged, grooved, sweat, or solvent socket. Wrong end type means the part cannot be installed at all.

Pressure Class
enum
Class 150

Sets flange drilling and the P/T curve. Class 125/250 on iron per ASME B16.1; Class 150/300/600 on steel per B16.5 and B16.34.

Body Material
enum
ASTM A351 CF8M (cast 316)

Drives chemical compatibility, temperature limit, and price. Buyers filter on the cast grade, not on the word 'stainless'.

Screen / Element Material
enum
316 stainless steel

The screen sees the same fluid as the body but is often a different alloy. A 304 screen in a 316 body is common and sometimes disqualifying.

Screen Opening (Perforation or Mesh)
enum · in / mesh
1/16 in (1.6 mm) perforated

The functional spec: what the strainer stops. Perforated sheet and mesh-lined cloth are different media and must never share one value.

Manufacturer Part Number (MPN)
identifier
F250-CI-020-062

The only key that survives cross-reference, RFQ, and supplier price file updates. Screen options usually extend the base MPN as a suffix.

GTIN / UPC
identifier
00812345678901

Required by marketplaces and by the PVF data pools. A missing GTIN blocks channel listing no matter how good the spec data is.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Screen Open Area Ratio
number · × pipe cross-sectional area
3.0 (3:1)

Free screen area divided by pipe cross-section. Sets clogged pressure drop and cleaning interval; specs call out a minimum, often 4:1 on baskets.

Micron Equivalent
number · µm
841 µm (nominal, 20 mesh)

How process buyers think and search. Mesh and perf do not convert cleanly — wire diameter and weave change the real opening, so flag it nominal.

Pressure–Temperature Rating
range · psi @ °F
150 psi steam / 400 psi WOG @ 150°F

A bare 'max 250 psi' is unusable. Iron and bronze bodies derate as they heat, and saturated steam service is rated separately from cold WOG.

Blowdown / Drain Connection
enum · in NPT
1/2 in NPT, plugged

Whether the cap or body is tapped for a blowoff valve, and at what size. Decides if the screen can be cleaned without breaking the line.

Seal & Gasket Material
enum
EPDM O-ring

EPDM, FKM, Buna-N, PTFE, or graphite. On thermoplastic and cover-gasketed bodies this is the chemical compatibility gate, not the body alloy.

Replacement Screen MPN
identifier
SCR-020-062-316

Screens are consumables sold as their own SKUs. Without the link back to the parent, the reorder goes to whoever cross-references it first.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

Country of Origin
enum
United States

Drives duty and TAA / Buy American eligibility on government, utility, and municipal work. The same series is often cast in two countries.

Design & Shell Test Standard
enum
ASME B16.34; shell tested per API 598

What the body was designed and tested to. B16.34 for steel bodies, B16.1 for iron flanges, API 598 shell test where the spec calls for it.

Potable Water Certification
enum
NSF/ANSI 61 & 372 certified

NSF/ANSI 61 for wetted materials, NSF/ANSI 372 for 0.25% weighted-average lead. Mandatory on domestic water, irrelevant on steam.

The fields that aren't in the schema at all

What most strainers catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Competitor signal
+ Screen Open Area Ratio

Specialist strainer suppliers publish OAR on every datasheet and engineers write a minimum ratio into the submittal. Distributor filter rails expose mesh and perf size but carry no free-area field.

The RFQ specifies 4:1 minimum, the catalog cannot prove it, and the line goes to someone who can — or an inside rep opens the PDF by hand on every quote.

Search signal
+ Micron Equivalent

Process and filtration buyers search in microns; strainer catalogs are indexed in mesh and fractional-inch perf. A search for '40 micron strainer' returns nothing on most PVF sites.

Zero results on a high-intent query. The buyer concludes the line isn't carried and goes to a filtration distributor whose catalog does index in microns.

Supplier signal
+ Pressure–Temperature Rating

Supplier price files carry a single 'max pressure' number with no temperature attached. The datasheet behind it has a full P/T curve, because iron and bronze bodies derate as they heat.

A cold-rated number gets quoted into a steam or hot-oil line. Best case an engineer catches it at submittal review; worst case it ships and fails in service.

Supplier signal
+ Blowdown / Drain Connection

Every strainer datasheet footnotes the blowoff boss size and whether it ships plugged. Catalogs keep it in free text if at all, so it is not filterable and not comparable across brands.

Buyer assumes a tapped boss, orders a blowoff valve alongside it, and the boss is cast solid or a different size. Return on the valve, delay on the install.

Marketplace signal
+ Replacement Screen MPN

Distributors list strainer screens as standalone SKUs with their own mesh and perf attributes, but nothing ties a screen back to the strainer bodies it actually fits.

The consumable reorder — the recurring half of this category — is unsearchable. Buyers call the manufacturer or buy from whoever built the cross-reference.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way pump, valve & process equipment suppliers spell it. A filter only works once they agree.

Screen Opening (Perforation or Mesh)
1/16"0.062 in062 PERF1.6 mm1/16 IN PERF20
1.6 mm (1/16 in) perforated

Perf and mesh share one supplier column: a bare '20' can be 20 mesh or 0.020 in perf. Media type has to be governed as its own field.

Body Material
SS316316SSCF8MA351 CF8MStainless Steel 316T316
Stainless steel, ASTM A351 CF8M (cast 316)

CF8M is the cast grade of 316. Wrought 316 and CF8M are not interchangeable on a pressure-temperature chart or in a submittal.

End Connection
FLGD 150#Flanged ANSI 150 RF150LB RF FLGFL RF 150ANSI B16.5 150#125# FF
Flanged, ASME B16.5 Class 150 RF

'150#' on an iron body is really ASME B16.1 Class 125. Bolt circle matches Class 150 steel; the pressure rating does not.

Strainer Type
Y-StrainerWye StrainerY TypeYSTRY-Pattern StrainerWye-type
Y-strainer (wye)

Half the supply base spells it 'wye'; buyers type 'y strainer'. One governed value keeps both search paths on the same facet.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Will a 20 mesh screen catch 800 micron particles, or do I need to go finer?
  • What's the open area ratio on this 3 in Y-strainer with 1/16 perf?
  • Is the blowoff port tapped and plugged, or do I have to drill it?
  • What's the actual pressure rating at 400°F, not at room temperature?
  • Which replacement screen fits this body, and is it 304 or 316?
  • Is this bronze body NSF/ANSI 61 and 372 certified for potable water?
  • Will Class 125 iron flanges bolt up to my Class 150 steel flanges?
  • Can I get this in CF8M with FKM seals instead of EPDM?

What channels require

The same SKU, different mandatory fields per destination.

Distributor's own site filter rail
Strainer TypeNominal Size (NPS / DN)End ConnectionPressure ClassBody MaterialScreen Opening (Perforation or Mesh)
Amazon Business
GTIN / UPCManufacturer Part Number (MPN)Country of OriginNominal Size (NPS / DN)Body MaterialStrainer Type
Trading Partner Connect (ASA PVF data pool)
GTIN / UPCManufacturer Part Number (MPN)Country of OriginUNSPSC codeNominal Size (NPS / DN)Potable Water Certification
Engineering submittal / RFQ package
Design & Shell Test StandardPressure–Temperature RatingScreen Open Area RatioScreen Opening (Perforation or Mesh)Body MaterialEnd Connection

Strainers data, in practice

Is mesh size the same as micron rating?

No. Mesh counts openings per linear inch of woven wire; micron is an approximate particle cut-off. The real opening depends on wire diameter and weave, so two 100-mesh cloths from different suppliers do not have the same opening. Published conversions are guides, not equivalences. Perforated sheet is a third thing again — holes punched in plate, sized in fractional inches or millimetres, commonly 1/32 in through 1/4 in. Carry three governed fields: media type (perforated / mesh-lined), opening in its native unit, and a micron equivalent flagged as nominal. Collapsing them into one 'mesh size' column is how a 0.020 in perf becomes a 20 mesh in the catalog.

What is open area ratio, and why should it be in the schema?

OAR is the strainer's free screen area divided by the cross-sectional area of the pipe it sits in. Free area is screen surface area times the percent open of the media — roughly 30% for standard perf in small sizes, closer to 40% at 2 in and larger. It governs pressure drop as the element loads: a 4:1 strainer can be half blinded and still have twice the pipe's area open. Engineers write minimums into specs, with 4:1 a common floor on baskets while Y-strainers often land nearer 2:1 to 3:1. It is the field that explains why you'd take a basket over a Y at the same size and perf — and it is almost never on a distributor filter rail.

Why do the same flanged ends get spelled a dozen ways?

Two standards collide. A steel or stainless body uses ASME B16.5 flanges in Class 150/300/600. A cast iron body uses ASME B16.1 flanges in Class 125/250. Class 125 iron and Class 150 steel share a bolt circle in common sizes, so suppliers, reps, and price files all write '150#' for both — but the pressure-temperature ratings differ, and iron derates further with heat. Normalize to standard plus class plus facing ('Flanged, ASME B16.1 Class 125 FF' vs 'Flanged, ASME B16.5 Class 150 RF') and validate the pairing against body material. An iron body carrying a B16.5 Class 150 value is a data error, not a variant.

How many attributes does a strainer need before it's listable?

Nine get it on the shelf: type, nominal size, end connection, pressure class, body material, screen material, screen opening, MPN, GTIN. Those answer 'will it fit and will it hold.' They do not answer 'is it the right one.' The differentiating fields — open area ratio, micron equivalent, the P/T pair, the blowdown port, the seal, the screen's own part number — are what a buyer compares two brands on, and they live in the datasheet PDF rather than the price file. A record that stops at nine is complete enough to list and too thin to win the line.

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