Zuverlässige Kondensatabführung: Hochwertige Gestra Kondensatableiter bei FERGO

Steam traps do a simple but essential job in any steam system: they get rid of condensate, air, and other gases that build up, all without wasting live steam. Keeping them working properly means your operation saves energy, equipment doesn't get damaged by sudden water slugs (water hammer), and everything gets the heat it needs - radiators, heat exchangers, even heated vessels. Whether it's pharmaceuticals, food processing, or chemical production, having exact steam control comes down to choosing dependable condensate drains.

Gestra BK, MK und UNA Dampfableiter: Qualität, die überzeugt

FERGO offers the full line of Gestra steam traps, known for their toughness, reliability, and flexibility. The BK, MK, and UNA series all tackle different demands and hold up to various condensate loads. Each trap is built from sturdy, rust-resistant materials - a solid steel body (1.0460/ASTM A105) with stainless steel inside - so they last. With standard flange connections (like EN 1092-1, PN40) and available sizes from DN15 to DN50, most models are stocked and ship quickly, ready to drop straight into your setup.

Ein Blick auf die Serien: BK, MK und UNA

BK Series: These are thermostatic traps that use a fine-tuned bimetallic element. They adjust smoothly to shifts in pressure and temperature, so they're reliable from startup when there's plenty of condensate to deal with. The BK15 DN 40/50 models, for example, are built tough for heavy use.
MK Series: Advanced thermostatic design with a corrosion-proof Hastelloy® membrane. The Rhombusline design packs efficiency into a compact shape. There are two main types: the MK45-1 uses a double membrane for smaller, steady flows; the MK45-2's flat membrane handles bigger jobs. Both come with a built-in Y-strainer to keep debris out.
UNA Series: These are mechanical float traps designed to let out condensate continuously at steam temperature. That means they're especially efficient for processes with large, steady condensate flow. The UNA45hl models, with DUPLEX control units like the AO32, are made for horizontal pipes and keep tight closure, so no leaks.

Gestra steam traps BK, MK, and UNA series – reliable and energy-efficient condensate discharge for industrial steam systems

PRODUCT CONFIGURATOR

Choosing the Right Gestra Steam Trap: Series Comparison

To help you select the ideal model for your application, here is a technical overview of the primary Gestra series available at FERGO:

Series & Type	Primary Operating Principle	Key Features & Model Examples	Ideal Application & Condensate Load
BK Series Thermostatic (Bimetallic)	Utilizes a bimetallic regulator. Models like the BK15 include an internal strainer and check valve. Robust construction for stable operation.	Principle: Thermostatic (Bimetallic) Models: BK15, BK25, BK45 Feature: Internal strainer and check valve Construction: Robust steel design	Excellent for applications with fluctuating pressures and temperatures Suitable for start-up conditions with large condensate loads For varying operating conditions and start-up procedures
MK Series Thermostatic (Membrane)	Features a tandem (5N1) or flat (5N2) Hastelloy® membrane. The MK45-1/MK45-2 includes a Y-strainer and integrated check valve. Compact Rhombusline design.	Principle: Thermostatic (Membrane) Models: MK45-1, MK45-2 Membrane: Hastelloy® tandem/flat membrane Equipment: Y-strainer and check valve integrated	MK45-1 for small condensate loads MK45-2 handles larger condensate volumes Ideal for steady, continuous drainage where energy efficiency is critical
UNA Series Mechanical (Float)	Uses a DUPLEX regulating unit with various closure organs (e.g., AO8, AO32). Designed for horizontal installation (e.g., UNA45hl). Provides continuous condensate drainage.	Principle: Mechanical (Float) Models: UNA45hl, UNA55 Unit: DUPLEX regulating unit Closure organs: AO8, AO32 available Installation: Horizontal	Perfect for applications requiring continuous drainage at full steam temperature For main steam lines and heat exchangers For high, constant loads and continuous operation

Series & Type

Primary Operating Principle

Key Features & Model Examples

Ideal Application & Condensate Load

BK Series

Thermostatic (Bimetallic)

Utilizes a bimetallic regulator. Models like the BK15 include an internal strainer and check valve. Robust construction for stable operation.

Principle: Thermostatic (Bimetallic)
Models: BK15, BK25, BK45
Feature: Internal strainer and check valve
Construction: Robust steel design

Excellent for applications with fluctuating pressures and temperatures
Suitable for start-up conditions with large condensate loads
For varying operating conditions and start-up procedures

MK Series

Thermostatic (Membrane)

Features a tandem (5N1) or flat (5N2) Hastelloy® membrane. The MK45-1/MK45-2 includes a Y-strainer and integrated check valve. Compact Rhombusline design.

Principle: Thermostatic (Membrane)
Models: MK45-1, MK45-2
Membrane: Hastelloy® tandem/flat membrane
Equipment: Y-strainer and check valve integrated

MK45-1 for small condensate loads
MK45-2 handles larger condensate volumes
Ideal for steady, continuous drainage where energy efficiency is critical

UNA Series

Mechanical (Float)

Uses a DUPLEX regulating unit with various closure organs (e.g., AO8, AO32). Designed for horizontal installation (e.g., UNA45hl). Provides continuous condensate drainage.

Principle: Mechanical (Float)
Models: UNA45hl, UNA55
Unit: DUPLEX regulating unit
Closure organs: AO8, AO32 available
Installation: Horizontal

Perfect for applications requiring continuous drainage at full steam temperature
For main steam lines and heat exchangers
For high, constant loads and continuous operation

Warum FERGO als Partner für Gestra Kondensatableiter?

FERGO isn't just a supplier - we're on your team when it comes to process efficiency. Our experts help you find the right Gestra BK, MK, or UNA steam trap for your exact pressure, temperature, and condensate requirements. With a large inventory, we minimize wait times and cut down on project delays.

If you're aiming for better steam system performance and fewer headaches, check out our complete lineup of Gestra condensate drains online or talk to our technical team for tailored advice and support. With FERGO, your operation gets the reliability it needs - without compromise.

Frequently Asked Questions – Steam Traps

A steam trap – also called a condensate trap or steam water drain – is a fully automatic valve that in steam systems discharges condensate, air, and non-condensable gases while preventing live steam from escaping. It solves one of the core challenges in steam engineering: condensate forms inevitably as soon as steam gives up heat – and if it is not continuously removed, system performance deteriorates significantly.

Condensate blocks heat transfer surfaces – Heat exchangers, heating coils, and jacketed vessels lose efficiency when condensate accumulates, because condensate is a far worse heat conductor than steam.
Entrained condensate causes water hammer – Liquid slugs in steam lines generate dangerous pressure surges that can damage pipework, valves, and plant equipment.
Non-condensable gases (air, CO₂) reduce heat transfer – They settle on heat transfer surfaces and reduce system output.

The steam trap opens automatically for condensate and gas – and closes immediately when steam is present. Depending on the operating principle, different designs use temperature, density, or pressure differences between steam and condensate to achieve this. FERGO stocks all variants of the GESTRA RHOMBUSline (BK, MK, DK, UNA) for immediate delivery.

FERGO stocks the complete GESTRA steam trap programme across four operating principles:

BK series (Thermostatic – Bimetallic) – The BK steam trap operates on the thermostatic bimetallic principle: Duostahl bimetallic plates respond to the temperature of the medium. Subcooled condensate opens the closing element – saturated steam closes it. Advantage: particularly robust, suitable for high pressures (PN40) and temperatures. The BK45 operates with back-pressure (condensate is discharged slightly subcooled) – ideal for energy-conscious operation and wherever immediate flash-free discharge is not required.
MK series (Thermostatic – Membrane) – The MK steam trap (MK45-1, MK45-2, MK45A-1, MK45A-2) uses a Tandem membrane (5N1) that responds to temperature differences between steam and condensate. Exceptionally compact, with an integrated strainer (Y-screen) and integrated non-return valve – a space-saving all-in-one solution. Ideal for small to medium condensate loads, radiators, process plants, and wherever installation space is limited.
DK series (Thermodynamic – Disc) – The DK47-L (low pressure) and DK47-H (high pressure) work on the thermodynamic disc principle: a free disc opens and closes through the pressure difference between incoming condensate and flash steam. Very robust, low-maintenance design with minimal moving parts. Suitable for tracer lines, steam main drainage, and intermittent condensate loads.
UNA series (Mechanical – Float) – The UNA45hl is a float steam trap with Duplex control trim for horizontal pipeline installation. The float opens the closing element proportionally to the condensate level – condensate is discharged immediately and continuously at saturation temperature (no back-pressure operation). Highest capacity; ideal for large condensate loads, heat exchangers, and process applications with continuous condensate generation.

The closing element (Abschlussorgan, AO) is the control valve inside the steam trap that regulates the flow of condensate and steam. The AO designation indicates the maximum permissible differential pressure (ΔP max) at which the steam trap operates reliably:

AO 2 – ΔP max 2 bar – for low-pressure steam systems and radiators in building services
AO 4 – ΔP max 4 bar – for low-pressure process steam systems
AO 8 – ΔP max 8 bar – standard range for medium-pressure industrial steam systems
AO 13 – ΔP max 13 bar – for medium to high operating pressures in the process industry
AO 22 – ΔP max 22 bar – for high-pressure steam systems in chemicals and power generation
AO 32 – ΔP max 32 bar – for the highest pressures, e.g. in power plants and petrochemical facilities

Selection rule: The closing element must be selected for the actual differential pressure between the steam pressure upstream of the steam trap and the back-pressure in the condensate return system. An incorrectly sized AO leads either to steam blow-through (AO too large) or insufficient condensate discharge (AO too small). Our FERGO experts are happy to recommend the correct closing element for your system.

Steam traps are indispensable in every steam system – wherever steam is used as a heating or process medium:

Industrial steam heating and HVAC – Radiators, tracer lines, air heaters, and building heating systems using steam. The steam trap keeps radiators steam-filled and reliably discharges condensate without heat loss through steam blow-through.
Heat exchangers and jacketed vessels – In process plants, steam heat exchangers and steam-heated reactors transfer heat to process media. Steam traps maximise heat transfer through immediate condensate discharge (UNA float preferred).
Pharmaceutical industry – Precise steam control for sterile processes, autoclaves, CIP/SIP systems, and cleanroom air conditioning. Steam traps must meet the highest hygienic and safety requirements.
Food and beverage industry – Steam heating, pasteurisation, sterilisation, and drying processes. Clean condensate discharge prevents steam blow-through and product contamination.
Chemical and petrochemical industry – Process steam for reactors, distillation columns, evaporators, and tracer heating of pipelines carrying highly viscous media or melts.
Power generation and power plants – High-pressure steam traps (AO 22 / AO 32) for steam turbines, feedwater heaters, and steam mains in gas, coal, and nuclear power plants.
Compressed air treatment – Certain steam trap types (particularly DK and BK) are also suitable for draining compressed air lines and vessels.

A faulty or incorrectly sized steam trap can have significant economic and safety consequences:

Steam blow-through (open steam trap) – If the steam trap remains permanently open or develops a leak, live steam escapes unused into the condensate network or the atmosphere. Since steam has a very high energy density, this causes substantial energy losses and direct additional costs for steam generation. In larger plants, faulty steam traps can account for 10–30% of total steam consumption.
Water hammer from condensate flooding – If the steam trap remains closed (flooding despite condensate accumulation) or becomes blocked, condensate collects in the steam line. Fast-moving steam picks up condensate slugs – the impact on bends, valves, and heat exchangers creates pressure surges (water hammer) that can cause pipe fractures and plant damage.
Performance loss from condensate flooding in heat exchangers – Accumulated condensate covers heat transfer surfaces and reduces effective heating area. Heat transfer coefficient falls, process times lengthen, and product quality suffers.
Regular steam trap inspection – GESTRA steam traps are designed for straightforward condition monitoring. Regular inspection (acoustic, thermographic, or with test instruments) ensures plant efficiency and prevents costly failures.

FERGO is an authorised GESTRA partner and stocks the complete GESTRA RHOMBUSline for immediate delivery. GESTRA (part of the Flowserve group) is one of the world's leading manufacturers of steam traps and steam valves:

High-quality materials – Body in steel (1.0460 / ASTM A105) or stainless steel (1.4027) for broad application ranges; internals in stainless steel (CrNi); gasket in graphite/CrNi for reliable sealing at high temperatures and pressures.
Comprehensive connection options – Threaded sockets to EN ISO 228-1, butt-weld ends to EN 12627, flanges PN10 / PN16 / PN40, ANSI Class 150, and ASME B16.5 Class 300 – for integration into any national or international pipeline system.
Wide pressure range – Closing elements from AO 2 to AO 32 (ΔP max 2–32 bar) cover all industrial steam pressure ranges.
Nominal sizes DN10 to DN65 – For all common condensate line sizes.
Face-to-face EN 1092-1 PN40 Form B1 – Standardised face-to-face dimensions (e.g. 150 mm or 160 mm) for straightforward installation and replacement in existing systems.
186 models from stock – FERGO stocks the complete GESTRA steam trap range for fast delivery without long lead times.

Selecting the optimal steam trap depends on several factors. The following parameters should be considered during sizing:

Operating pressure and back-pressure – The differential pressure between the steam pressure upstream of the steam trap and the back-pressure in the condensate return system determines the required closing element (AO 2 to AO 32). Never select an AO smaller than the actual differential pressure.
Condensate load – Small to medium loads: MK membrane trap or BK bimetallic trap. Large, continuous condensate loads: UNA float trap for immediate discharge at saturation temperature.
Installation orientation – The UNA45hl is designed for horizontal pipework (hl = horizontal left). BK and MK are generally more flexible in installation orientation.
Operating mode – Continuous process operation (UNA float preferred for immediate condensate discharge) or intermittent operation (BK or DK suitable).
Application type – Steam main drainage / tracer lines: DK disc trap. Radiators / small process plants: MK membrane trap. Heat exchangers / large process plants: UNA float trap.
Material – Steel for standard steam; stainless steel (1.4027) for higher corrosion requirements or aggressive condensates (e.g. CO₂-laden condensate).

Our FERGO team is happy to advise on sizing and selection of the optimal GESTRA steam trap for your specific application.

The GESTRA MK45 (available as MK45-1, MK45-2, MK45A-1, MK45A-2) is a particularly well-engineered compact solution that combines three functions in a single body:

Thermostatic membrane steam trap – The patented Tandem membrane 5N1 opens with subcooled condensate and closes with steam. The membrane combines high response sensitivity with long service life and straightforward replacement of the control trim.
Integrated strainer (Y-screen) – Protects the membrane and closing element from particles and deposits from the steam line. In a separate system, an upstream strainer would be required – here it is already built in. Saves installation space, reduces assembly effort, and eliminates a potential leak point.
Integrated non-return valve – Prevents back-flow of condensate from the return system into the steam plant during pressure drops. Protects against condensation and water hammer during pressure fluctuations in the condensate network.

The MK45 is therefore ideal for space-restricted installations, retrofitting, and wherever a compact, fully equipped steam trap is needed without additional upstream and downstream fittings. Nominal sizes DN10 to DN50, PN40, flanged or threaded.