Strainers & Steam Traps

Quick pick (TL;DR)

Strainer: Y-type for small bore & protecting pumps/control valves; basket for large bore / high dirt; temporary cone for commissioning; duplex for no-shutdown cleaning.
Steam trap: F&T for process (modulating) loads, thermodynamic for drip/tracing, inverted bucket for high-pressure/superheat.
Size the trap at ~2–3× condensate load.

Strainers — type selection

Type	Best for
Y-type	Small bore, protect equipment.
Basket	Large bore, high dirt load.
Temporary cone	Commissioning only.
Duplex	No-shutdown cleaning.

Frequently asked questions

What should I know about Strainers & Steam Traps?

Strainer: Y-type for small bore & protecting pumps/control valves; basket for large bore / high dirt; temporary cone for commissioning; duplex for no-shutdown cleaning. Steam trap: F&T for process (modulating) loads, thermodynamic for drip/tracing, inverted bucket for high-pressure/superheat. Size the trap at ~2–3× condensate load.

Which standards or codes apply?

choose the mesh fine enough to protect the downstream item (≈ 40 mesh general; 100+ mesh ahead of control valves/instruments) and ensure the screen open area is ≥ 3× the pipe bore area to keep pressure drop and clogging low.

Strainer sizing — Mesh ≈ 40 general, 100+ before instruments; open area ≥ 3× pipe bore.

Steam traps — type selection

Type	Best for	Watch out
F&T	Process, modulating load.	Water hammer / superheat.
Thermodynamic	Drip / tracing.	Noisy; low-ΔP.
Thermostatic	Tracing / air venting.	Slow; backs up condensate.
Inverted bucket	High pressure / superheat.	Loses prime on sudden ΔP drop.

Steam trap sizing

Worked example

Given Condensate load = 500 kg/h Differential pressure ΔP = 5 bar Step 1 — Safety factor trap capacity = load × SF (use 2–3 for process) = 500 × 2 = 1000 kg/h Step 2 — Select at ΔP pick a trap rated ≥ 1000 kg/h at 5 bar ΔP type = modulating process → F&T trap

Start-up condensate load far exceeds running load — hence the factor.

Steam-trap sizing calculator

Trap capacity from condensate load

Required capacity = condensate load × safety factor (×2–3).

Condensate (kg/h)

Safety factor

ΔP (bar)

Capacity falls with ΔP — size at the minimum ΔP. Match trap type to the duty.

Common mistakes

Wrong strainer mesh.
Temporary cone left in permanently.
F&T on superheat → failure.
No safety factor → flooding.

Requisition & datasheet

Strainer: type, mesh, screen, body/size.
Trap: type, capacity ×SF at ΔP.

Standards — Manufacturer charts; ASME B16.34; ISO 6552/6553.