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Armstrong International — Steam Traps & Steam System Components · Memphis, TN

Armstrong International Steam Traps —
Series 811, 880, 882CV Inverted Bucket Traps & Repair Parts

Memphis Control Center stocks Armstrong International steam traps and steam system components — Series 811 inverted bucket steam traps (15–250 PSI), Series 880 and 882CV inverted bucket traps with integral strainer, pressure reducing valves, air vents, and a full line of steam trap repair parts including gaskets, stem and guide kits, seal packs, and orifice assemblies. Armstrong International has been the industry standard in steam trap technology since 1900 — inventors of the inverted bucket steam trap. Free same-day shipping from Memphis, TN since 1967.

Need Help Selecting a Trap? Call (901) 458-2000
Armstrong International Distributor Inverted Bucket · Thermodynamic · PRVs & Repair Parts Traps & Repair Parts Free Same-Day Shipping
Invented in 1911Armstrong International invented and patented the inverted bucket steam trap — the industry standard for over 100 years
Founded 1900 — Family OwnedFifth-generation family-owned company headquartered in Three Rivers, Michigan
Full Product RangeInverted bucket traps (800, 811, 880 series), thermodynamic traps, PRVs, air vents, and repair parts
Same-Day ShippingOrders by 2 PM CT ship same day — always free

Note — Armstrong International vs. Armstrong Fluid Technology: This page is for Armstrong International (Three Rivers, Michigan — steam traps, PRVs, and steam system equipment). Armstrong Fluid Technology is a separate company that makes hydronic circulators and commercial HVAC pumps. For pumps and pump parts, see our Armstrong Fluid Technology page.

Armstrong Steam Trap Series

Armstrong manufactures three primary types of steam traps — each suited to different steam system applications. Contact our team or call (901) 458-2000 for trap selection assistance.

Inverted Bucket Series 811 · 812 · 813 · 815 · 816

Armstrong Inverted Bucket Steam Traps — the original Armstrong design, patented 1911. The inverted bucket mechanism uses steam buoyancy to keep the bucket floating (valve closed). When condensate accumulates and fills the bucket, it sinks — a unique leverage system multiplies the bucket's force to pull the valve off its seat (valve open), discharging condensate. The valve and orifice are located at the top of the trap, away from dirt. Inverted bucket traps discharge intermittently (not continuously), are resistant to water hammer, and the valve seal actually improves with normal wear. Robust, durable design suited for steam mains, drip legs, tracer lines, and process equipment. Available from 15 PSI to 600 PSI depending on series. Series 811 is the most common — available in 3/4" NPT at 15, 30, 70, 125, 200, and 250 PSI. Series 812 and 813 are related variants in the 800 series family. Series 814, 815, and 816 cover larger pipe sizes and higher pressure ranges. All are cast iron inverted bucket traps with free-floating stainless steel mechanisms.

Inverted Bucket Series 811 · 812 · 813 · 815 · 816 15–600 PSI 3/4" · 1" · 1-1/4" · 1-1/2" · 2" NPT
Inverted Bucket · Integral Strainer Series 880 · 882CV

Armstrong Series 880 and 882CV — Inverted Bucket Steam Traps with Integral Strainer. The 880 series is an inverted bucket trap with a built-in integral strainer — the same proven inverted bucket operating principle as the 811/812 series, with the added benefit of an integral strainer that eliminates the need for a separate upstream strainer. The 882CV adds an internal check valve (the "CV" suffix on all Armstrong trap models indicates an internal check valve). Cast iron construction, free-floating stainless steel mechanism, continuous automatic air venting via a vent hole in the bucket. Capacities to 4,400 lb/hr.

Inverted Bucket Integral Strainer Series 880 · 882CV CV = Internal Check Valve Up to 4,400 lb/hr
Thermodynamic Series 881 · 881T

Armstrong Thermodynamic (TD) Steam Traps. Thermodynamic traps use a disc valve that opens and closes based on pressure differences between flash steam and condensate. When hot condensate enters the trap, it flashes to steam under low-pressure conditions — this flash steam pressure holds the disc valve closed, trapping live steam. As the flash steam condenses, the pressure drops, the disc lifts, and condensate discharges. Simple, compact design with only one moving part (the disc). Suited for steam mains, superheated steam, and tracer lines where minimal maintenance and compact size are priorities. Armstrong Series 881 and 881T are the standard thermodynamic trap configurations. Available in stainless steel construction for corrosive or high-temperature applications.

Thermodynamic Disc Series 881 · 881T Stainless Steel Available Superheated Steam
System Components PRVs · Air Vents · Repair Parts

Armstrong Pressure Reducing Valves, Air Vents & Repair Parts. GP-2000 Series — pressure reducing valves available in 1" and 1-1/2" NPT. 816T Series — inverted bucket steam traps with thermic vent bucket ("T" suffix = thermic vent bucket, not PRV). D41790 — air vent (1/2" FPT × 3/4" MPT, 150 PSI). Repair parts: gaskets (A21389-1 for 216/316/416 traps), stem and guide kits (D25723), seal packs (D51825), orifice/PCA assemblies (B1673 series), GP-2000 repair kits (D25246, D25177), and TVS trap valve stations (D500617). Contact us with your trap model for the correct repair kit.

GP-2000 Pressure Reducing Valves 816T Thermic Bucket Traps TVS Trap Valve Stations D41790 Air Vents A21389-1 Gaskets D25723 Stem & Guide Kits

Series 811 Inverted Bucket Trap — Pressure Ratings

The Armstrong 811 is the most widely stocked inverted bucket steam trap. SKU format: 811-[pipe size]-[max PSI]. 3/4" NPT is the most common pipe size. Select the PSI rating that matches your steam system working pressure — the trap must be rated at or above system pressure.

SKUPipe SizeMax PSIApplicationShop
811-3/4-153/4" NPT15 PSILow pressure steam systemsShop
811-3/4-303/4" NPT30 PSILow-medium pressure steamShop
811-3/4-703/4" NPT70 PSIMedium pressure steam systemsShop
811-3/4-1253/4" NPT125 PSIStandard commercial steam pressureShop
811-3/4-2003/4" NPT200 PSIMedium-high pressure steamShop
811-3/4-2503/4" NPT250 PSIHigh pressure steam systemsShop
812CV-3/4-303/4" NPT30 PSISeries 812 variant with check valveShop
816T-2½-[psi]2-1/2" NPT15–250 PSIInverted bucket trap with thermic vent bucket (T suffix)Shop
GP-2000-1.5-[psi]1-1/2" NPTVariousGP-2000 pressure reducing valveShop

Can't find your size or pressure rating? Contact us or call (901) 458-2000 — we carry Armstrong International products across steam traps, repair kits, and accessories.

Armstrong International — Commonly Ordered

View all 1,314 →
811-3/4-15Inv. Bucket · 3/4" NPT · 15 PSI 811-3/4-125Inv. Bucket · 3/4" NPT · 125 PSI 811-3/4-250Inv. Bucket · 3/4" NPT · 250 PSI 213-3/4-125Inv. Bucket · 3/4" NPT · 125 PSI 213-3/4-30Inv. Bucket · 3/4" NPT · 30 PSI 880-3/4-125Inv. Bucket · Integral Strainer · 125 PSI 880-1/2-125Inv. Bucket · Integral Strainer · 1/2" NPT 882CV-1/2-125Inv. Bucket · Strainer · Check Valve · 125 PSI 882CV-1/2-250Inv. Bucket · Strainer · Check Valve · 250 PSI 816T-2½-125Inv. Bucket · Thermic Bucket · 2-1/2" · 125 PSI GP-2000-1.5Pressure Reducing Valve · 1-1/2" NPT D500617 (TVS-811S)Trap Valve Station · 3/4" · 30 PSI D41790Air Vent · 1/2" FPT × 3/4" MPT · 150 PSI A21389-1Gasket for 216, 316, 416 Traps D25723Stem & Guide Kit D51825Seal Pack B1673-5PCA Orifice for 215, 815 Traps All 1,314 ProductsBrowse complete Armstrong International catalog

Armstrong International

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Armstrong International is a leading provider of intelligent system solutions for steam, air, and hot water utility applications. With a strong focus on energy efficiency and sustainability, Armstrong International offers a wide range of products and services including steam traps, pressure and temperature controls, and humidification systems. With over a century of experience in the industry, Armstrong International has established itself as a trusted partner for businesses looking to optimize their utility systems. By leveraging innovative technologies and expert engineering, Armstrong International helps customers improve efficiency, reduce costs, and enhance overall performance. Trust Armstrong International for all your steam and utility needs.

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Need help selecting an Armstrong steam trap or repair part?

Tell us your pipe size, steam pressure, and application — we'll identify the right trap and series.

Talk to an Expert Call (901) 458-2000

Armstrong International — Frequently Asked Questions

Common questions about Armstrong International steam traps and steam system products. Contact our team or call (901) 458-2000 for product selection help.

What is the difference between Armstrong International and Armstrong Fluid Technology?

Armstrong International (founded 1900, Three Rivers, Michigan) makes steam traps, pressure reducing valves, condensate recovery equipment, and steam system components. They invented the inverted bucket steam trap in 1911. Armstrong Fluid Technology (founded 1934, Toronto, Ontario) is a completely separate company that makes hydronic circulators, commercial HVAC pumps, and pump repair parts. Memphis Control Center stocks both — Armstrong International steam products are on this page; Armstrong Fluid Technology pumps and parts are on our Armstrong Fluid Technology page.

What is an inverted bucket steam trap and what is it used for?

An inverted bucket steam trap uses buoyancy to distinguish between steam and condensate. When steam enters, it fills the inverted bucket (open end down) causing it to float — this closes the discharge valve and retains steam. When condensate accumulates and the bucket sinks, the valve opens and condensate drains. Armstrong International invented the inverted bucket steam trap in 1911. Inverted bucket traps are durable and resistant to water hammer — well suited for steam mains, drip legs, tracer lines, and process piping. The Armstrong Series 811 is the most widely used model.

How do I read an Armstrong International steam trap part number?

Armstrong steam trap part numbers follow the format: Series — Pipe Size — Maximum PSI. For example: 811-3/4-125 = Series 811 inverted bucket trap, 3/4" NPT connections, 125 PSI max working pressure. 880-3/4-125 = Series 880 inverted bucket trap with integral strainer, 3/4" NPT, 125 PSI. 882CV-1/2-250 = Series 882 inverted bucket trap, integral strainer, internal check valve (CV suffix), 1/2" NPT, 250 PSI. Always match the PSI rating to your system's working steam pressure — the trap must be rated at or above the system operating pressure.

What is the difference between Armstrong inverted bucket, inverted bucket with integral strainer, and thermodynamic steam traps?

The three main steam trap types differ in operating mechanism and best applications: Inverted bucket (Series 811, 812, 815, 816) — intermittent discharge, durable, suited for steam mains, drip legs, and tracer lines. Inverted bucket with integral strainer (Series 880, 882CV) — same inverted bucket principle as the 811/812 series with a built-in integral strainer; the 882CV adds an internal check valve (CV suffix). Thermodynamic disc (Series 881, 881T) — a disc valve opens and closes based on flash steam pressure differences; compact with one moving part; suited for steam mains and superheated steam. Not sure which type your application needs? Call us at (901) 458-2000.

What repair parts do you stock for Armstrong International steam traps?

We stock Armstrong International steam trap repair parts including: A21389-1 gaskets for 216, 316, and 416 series traps; D25723 stem and guide kits; D51825 seal packs; and B1673 series orifice/PCA assemblies for 215 and 815 series traps. The correct repair kit depends on your trap series and model number. Call us at (901) 458-2000 or contact us with your trap model for correct part identification.

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For emergencies, outside of business hours, call #901-604-7069