Industriearmaturen Threaded Check Valves

Threaded Check Valves in Brass & Stainless Steel — Buy Online

Threaded check valves in brass with NBR or stainless steel 1.4408 with Viton seat, BSP or NPT female thread, 1/4″ to 4″, up to PN16. Spring-loaded, silent operation.

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Product Overview

Threaded Check Valves: Compact Non-Return Protection for Small-Bore Pipework

A threaded check valve — also called a threaded non-return valve or a female thread check valve — screws directly into the pipeline through a machined female thread and stops flow reversal automatically. Inside the body, a spring holds the disc against its seat until forward flow lifts it clear; as soon as the flow drops or reverses, the spring pushes the disc back onto the seat before backflow can develop. Consequently the spring-loaded design closes silently, prevents water hammer and works in any installation position — vertical, horizontal or inverted.

Fergo supplies the RV101 in stainless steel 1.4408 or 1.4301 with a Viton (FKM) seat and a PTFE guide bearing, and the RV102 in brass with an NBR seat. Nominal sizes range from 1/4 inch up to 4 inch, and pressure ratings reach PN16. The female thread is available as BSP parallel to ISO 228/1 for European pipework or as NPT to ASME B1.20.1 for US-standard installations. A brass version with a metallic seal is available where the medium exceeds the temperature limits of the elastomer seats.

Threaded check valves protect pumps, compressors, boilers, dosing skids and instrumentation lines throughout HVAC circuits, compressed air systems, water treatment, chemical dosing, laboratory rigs and gas branches. The compact body screws straight into a tee or an elbow, so no additional flanges or brackets are required. Where larger nominal sizes or flanged connections take over, the wafer check valve and the dual plate check valve ranges cover DN25 upwards, and for pump-discharge duty the ball check valve range provides a silent alternative in wastewater and dirty water service.

Subcategories: Threaded Check Valves by Material and Sealing

01 RV101 — Stainless Steel Threaded Check Valve with Viton Seat

The RV101 stainless steel threaded check valve combines a body, disc and spring in 1.4408 / CF8M or 1.4301 with a PTFE guide bearing and a Viton (FKM) seat. The female thread follows BSP parallel to ISO 228/1, and sizes run from 1/4 inch up to 4 inch at a consistent PN16 rating. The operating temperature reaches +150 °C, which makes this variant suitable for chemical dosing, hot water circuits, condensate lines and process gas branches. Note that the RV101 is designed for pressurised service only and is not rated for vacuum applications.

02 RV102 — Brass Threaded Check Valve with NBR Seat

The RV102 brass threaded check valve uses a brass body, disc and spring with an NBR seat ring. Two thread standards are available: BSP parallel to ISO 228/1 for the European market and NPT to ASME B1.20.1 for the UK and US markets. Sizes span 1 inch up to 4 inch, and operating limits are: −20 °C to +100 °C for compressed air, 0 °C to +90 °C for water and −20 °C to +60 °C for gas. Maximum pressure is PN16 at smaller bores and PN12 at the largest sizes. The RV102 is the economical choice for HVAC systems, compressed air installations and general utility service.

03 Brass Threaded Check Valve with Metallic Seal

Where the medium exceeds the temperature limits of NBR or Viton, Fergo also supplies a brass threaded non-return valve with a metallic seal. The metal-to-metal sealing surface handles steam, hot water and thermal oil that would degrade elastomer seats, and the operating pressure remains in the 0 to 12 bar range. Female-thread connection to ISO 228/1. This design is the right choice for boiler drain lines, thermal-oil circuits and small-bore steam applications where a soft-seated check valve would fail prematurely.

Materials in Detail: Specifying the Right Threaded Check Valve

Body Materials — Brass or Stainless Steel

1. Brass (RV102 and Metallic-Seal Variant)

Application: HVAC systems, compressed air, water supply, glycol circuits, neutral gases, condensate return, general utility pipework at moderate temperatures

Temperature: air −20 °C to +100 °C · water 0 °C to +90 °C · gas −20 °C to +60 °C · PN12 to PN16

Advantages: excellent machinability produces clean female threads, good corrosion resistance in water and neutral gases, compact and economical, wide size availability from 1 inch up to 4 inch

Limitations: unsuitable for ammonia, aggressive chemicals, strongly chloride-rich water and hydrofluoric acid

2. Stainless Steel 1.4408 / CF8M and 1.4301 (RV101)

Application: chemical dosing, hot water circuits, condensate lines, food and pharmaceutical processes, chlorinated water, marine and outdoor installations

Temperature: up to +150 °C · PN16

Advantages: molybdenum-alloyed 1.4408 resists pitting from chlorides and salt spray, dimensionally stable under pressure, no metal-ion pickup into the medium, hygienic surface suits CIP processes, single-material construction across body, disc and spring for consistent expansion behaviour

Limitations: higher material cost than brass; the RV101 is not designed for vacuum service, so specify a dedicated vacuum check valve for such duty

Seat and Sealing Materials

1. NBR (Nitrile Butadiene Rubber) — RV102 Standard Seat

Application: compressed air, mineral oils, animal and vegetable fats, fuels, neutral gases and water at moderate temperature

Temperature: −20 °C to +100 °C in air · 0 °C to +90 °C in water · −20 °C to +60 °C in gas

Advantages: outstanding oil and grease resistance, good low-temperature flexibility, tight bubble-free shut-off, the economical elastomer choice for HVAC and utility service

Limitations: not suitable for hot water above 90 °C, steam, ozone, strong acids or oxidising chemicals

2. FKM / FPM (Viton) — RV101 Standard Seat

Application: aggressive chemicals, solvents, aromatic hydrocarbons, chemical dosing lines, hot water and condensate service

Temperature: up to +150 °C · PN16

Advantages: very high chemical and thermal resistance, ozone-resistant, handles a much broader spectrum of process media than NBR at elevated temperatures

Limitations: not compatible with ketones, esters, hot water or steam beyond the rated limit; premium price compared with NBR

3. PTFE Guide Bearing (RV101)

Application: guides the disc along the spring axis in every RV101 stainless steel variant

Temperature: matches the seat envelope

Advantages: very low friction reduces cracking pressure, resists chemical attack across the process range, avoids stick-slip behaviour and delivers repeatable opening characteristics over thousands of cycles

Limitations: softer than metal, so abrasive solids should be filtered out upstream

4. Metallic Seal (Brass Variant)

Application: steam, hot water above 100 °C, thermal oil, hot gases and any service beyond the temperature limits of NBR or Viton

Temperature: up to the material limit of the brass body

Advantages: maximum thermal durability, no ageing of the sealing element, bi-directional metal-to-metal contact, long service life in cyclic hot-service duty

Limitations: lower leak-tightness than soft-seated variants; slightly higher cracking pressure required to lift the disc against the spring

Fergo threaded check valves comply with the Pressure Equipment Directive 2014/68/EU. Depending on nominal size and rated pressure, smaller versions may be covered by the sound engineering practice provision of Article 4.3, while larger versions carry the full CE mark. Thread connections follow either DIN EN ISO 228-1 for the BSP parallel standard used across Europe, or ASME B1.20.1 for the NPT standard used in the United Kingdom and the United States. Face-to-face and end-to-end dimensions correspond to the shipped product datasheet for each nominal size.

Threaded bronze and brass check valves fall within the scope of MSS SP-80, the US industry standard that specifies design, materials, testing and marking requirements for bronze gate, globe, angle and check valves — Fergo’s RV102 series follows the SP-80 material and construction philosophy. Inspection documents to EN 10204 — the type 2.2 works certificate or the type 3.1 inspection certificate — are available on request. A full overview of all certificates is published on the Fergo certificate page. For aggressive chemical service that exceeds the limits of Viton, the PFA-lined check valve range extends the programme further. You can verify seat and body compatibility with your medium beforehand using the Fergo resistance check.

Fergo holds more than 25,000 industrial valves in stock. Threaded check valves in the RV101 stainless steel series and the RV102 brass series are available in every common thread size from 1/4 inch up to 4 inch, in BSP parallel and in NPT connections, and with elastomer or metallic seals. Because the female thread screws straight into the pipeline, no additional flanges, gaskets or brackets are required — the valve ships ready to install. For flanged designs and larger nominal sizes, the wafer check valve and dual plate check valve ranges complete the check-valve programme.

Fergo ships across Europe — including the United Kingdom, the Nordic countries and all other EU member states. Threaded check valves travel by parcel service, so express shipping delivers within the next working days. You will find shipping costs, payment options and express terms on the shipping and payment terms page. For special thread sizes, sanitary tri-clamp connections, PTFE-seated designs or complete dosing skid packages, please contact us through the customised solutions section.