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Industriearmaturen Steam Traps

Steam Traps by GESTRA — BK, MK & UNA Ex Stock

GESTRA steam traps in thermodynamic, thermostatic and ball-float design, steel or stainless steel body, DN15 to DN100, PN16 to PN40, flanged, threaded or weld-end.

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Steam Traps
  • Gestra BK Steam Trap

    Gestra BK Steam Trap

    Sizes: DN15 – DN50

    Flange connection: ANSI 150, PN40, ANSI 300, ANSI 600, ANSI 900, ANSI 1500, PN100, PN63, PN160

    Case material: 1.0460, 1.5415, 1.7335, 1.7383, 1.4901

    Connection: Threaded fittings, weld-on sleeves, weld-on ends, flanges

  • Gestra Steam Trap DK

    Gestra Steam Trap DK

    Sizes: DN15 – DN25

    Flange connection: ANSI 150, PN40, ANSI 300

    Case material: 1.0460, 1.4027, 1.4021

    Connection: Internal threads, welded sockets, welded ends, flanges

  • Gestra MK Steam Trap

    Gestra MK Steam Trap

    Sizes: DN15 – DN50

    Flange connection: ANSI 150, PN40, ANSI 300

    Case material: 1.0619, 1.4301, 1.4404, 1.0460

    Connection: Threaded fittings, welded sockets, welded ends, flanges, clamps

  • Gestra UNA Series Steam Traps

    Gestra UNA Series Steam Traps

    Sizes: DN15 – DN100, 1/2" – 2 1/2"

    Flange connection: ANSI 150, PN16, PN40, ANSI 300, ANSI 600, ANSI 900, PN25, PN100, PN63, PN160

    Case material: 1.4408, 1.0619, 1.4404, 1.0460, 1.5415, 1.7335, 5.3103, 1.5419, 1.7357, 5.1301

    Connection: Internal threads, weld-on sockets, weld-on fittings, flanges

  • Gestra Steam Traps – Special Traps

    Gestra Steam Traps – Special Traps

    Sizes: DN15 – DN150

    Flange connection: ANSI 150, PN16, PN40, ANSI 300, PN25

    Case material: 1.0619, 1.0460, EN-JM 1030, EN-JL 1040

    Connection: Internal threads, external and internal threads, weld ends, flanges

Produktübersicht

GESTRA Steam Traps: Reliable Condensate Discharge

A steam trap discharges condensate and non-condensable gases from a steam line while blocking live steam. As a result, it keeps heat exchangers, tracer lines and steam mains dry and free of air locks. This raises heat transfer, prevents water hammer and cuts overall energy consumption in the steam system.

Fergo supplies the full range of GESTRA steam traps. The BK thermodynamic series uses a control disc that closes on kinetic steam energy. The MK thermostatic series relies on a temperature-controlled membrane capsule and follows the saturated steam curve closely. The UNA ball float series discharges condensate immediately through a rolling float. Nominal sizes cover DN15 to DN100, with connection options as flange to EN 1092-1, female thread to ISO 228-1 or a weld end. Pressure ratings run from PN16 through PN40, complemented by ANSI Class 150 and 300 on selected models.

Steam traps serve heat exchangers, distillation columns, autoclaves, drying drums, tracing systems, steam distribution manifolds and boiler condensate return. In cyclic processes the thermodynamic BK is often first choice, while the membrane MK proves itself on superheated steam and tracer lines. The ball float UNA handles high condensate loads without back-up. An upstream Y-strainer keeps the internals of every trap clean and extends service life.

Subcategories: Steam Traps by Operating Principle

01 Thermodynamic Steam Traps (GESTRA BK series)

The thermodynamic steam traps of the GESTRA BK family work with a single moving part — the control disc. Rising steam velocity pulls the disc onto the seat and blocks the trap, while cooler condensate reopens it. This compact design suits steam mains, tracer lines and superheated steam applications up to PN40 and elevated temperatures. Sizes span DN15 to DN25 with flanged, threaded or weld-end connection. The BK is robust, air-vents automatically at start-up and needs virtually no maintenance.

02 Thermostatic Membrane Steam Traps (GESTRA MK series)

The thermostatic steam traps of the GESTRA MK family close through a temperature-controlled membrane capsule. The capsule reacts within a few degrees of the saturated steam curve, so condensate leaves the trap slightly sub-cooled. As a result, no live steam is lost. The MK excels on tracing systems, small heat exchangers and instrument lines. Sizes reach DN25, with PN40 and thread, flange or weld-end connection.

03 Ball Float Steam Traps (GESTRA UNA series)

The ball float steam traps of the GESTRA UNA family use a stainless steel rolling float that opens the drain valve as soon as condensate collects. Consequently the trap discharges continuously and handles very high loads without back-up. An integrated thermostatic air vent additionally releases non-condensable gases at start-up. UNA models cover DN15 to DN100 at PN16, PN25 and PN40. They are the reference solution for heat exchangers, autoclaves and process vessels where dry, condensate-free steam matters most.

Materials in Detail: Specifying the Right Steam Trap

Body Materials

1. Carbon Steel 1.0619 / ASTM A216 WCB

  • Application: standard body of the BK, MK and UNA series for saturated and superheated steam mains, tracer lines and general industrial service
  • Temperature: up to +400 °C · PN16 to PN40, ANSI Class 150 / 300
  • Advantages: high mechanical strength, good weldability, proven at elevated temperatures and pressures, economical for the wider steam network
  • Limitations: not corrosion-resistant against aggressive condensate or chloride-rich media

2. Stainless Steel 1.4408 / CF8M (AISI 316)

  • Application: chemical and pharmaceutical steam service, hygienic condensate return, condensate with dissolved oxygen or CO₂
  • Temperature: up to +400 °C (grade dependent)
  • Advantages: high corrosion resistance through molybdenum, hygienic surface, no iron contamination of the condensate
  • Limitations: higher material cost than carbon steel, longer lead time on larger sizes

3. Special Alloys on Request

  • Application: highly corrosive condensate, high chloride content, or extreme temperature service beyond standard steel and stainless steel
  • Temperature: application dependent
  • Advantages: exact match to the process conditions, extends the operating window of the standard GESTRA programme
  • Limitations: special order with surcharge and extended lead time

Internals and Sealing

1. Thermodynamic Disc (Hardened Stainless Steel)

  • Application: single moving control disc of the BK series
  • Temperature: up to +400 °C
  • Advantages: only one wear-relevant component, hardened surface resists erosion by wet steam, high cycle life
  • Limitations: small discharge losses per cycle; not the ideal choice for very light condensate loads

2. Thermostatic Membrane Capsule (MK)

  • Application: temperature-controlled discharge element of the MK series
  • Temperature: reacts within a few kelvin of the saturated steam curve
  • Advantages: condensate leaves slightly sub-cooled, essentially zero live-steam loss, ideal for tracing and instrument lines
  • Limitations: membrane is a wear part with a defined lifetime; upstream strainer strongly recommended

3. Stainless Steel Ball Float and Air Vent (UNA)

  • Application: discharge mechanism of the UNA series with an integrated thermostatic air vent
  • Temperature: up to +400 °C body-dependent
  • Advantages: continuous discharge, very high condensate capacity, air vent releases non-condensable gases at start-up, no back-up in the exchanger
  • Limitations: more moving parts than the BK; requires correct orientation on installation

4. Graphite Body Gaskets and TA-Luft Stem Sealing

  • Application: static and stem sealing on all GESTRA steam traps
  • Temperature: up to +400 °C
  • Advantages: proven graphite gasket withstands steam cycling, TA-Luft-compliant sealing meets emission limits, low-maintenance
  • Limitations: graphite gaskets are single-use and must be replaced after each disassembly

Certificates & Standards for Steam Traps

Fergo GESTRA steam traps comply with the Pressure Equipment Directive 2014/68/EU and carry the CE mark. Flange connections follow DIN EN 1092-1, and threaded connections follow ISO 228-1. Face-to-face lengths follow EN 558-1. TA-Luft-compliant stem sealing is standard, and AD2000 compliance is available for pressure vessel installations under German rules. The functional performance of the traps is tested to EN 12266 and EN 27841 / ISO 6704 for steam-loss measurement.

Inspection documents to EN 10204 — type 2.2 works certificate or type 3.1 inspection certificate — are supplied on request. A full overview of all certificates is published on the Fergo certificate page. For safety-relevant steam service, the GESTRA steam trap range is often combined with steam-tight globe valves for isolation and with the GESTRA check valves RK 86 / 86A downstream to prevent condensate return.

Delivery & Availability

Fergo holds more than 25,000 industrial valves in stock, including a dedicated GESTRA stock programme for the BK, MK and UNA steam trap series. Standard sizes are picked the same working day, so delivery follows within two to seven working days. Common spare parts — thermodynamic discs, membrane capsules and float assemblies — are also kept in stock and can be ordered separately.

Fergo ships across Europe — including the United Kingdom, the Nordic countries and all other EU member states. Smaller threaded traps travel by parcel service, whereas flanged and consolidated shipments go by forwarding agent. You will find shipping costs, payment options and express terms on the shipping and payment terms page. For steam-system surveys, energy audits, special alloys or 3.1 material certificates, please contact us through the customised solutions section.