Thermostatic membrane steam trap - MK | Gestra

GESTRA MK – Thermostatic Membrane Steam Trap

The GESTRA MK series employs a thermostatic membrane regulator for condensate removal and steam line venting. It is applied in steam tracing, distribution network drainage, small heat exchangers, and locations where limited condensate accumulation is acceptable before discharge.

Technical Operation

The capsule opens at low temperatures to remove air and cold condensate. As temperature increases, it closes near saturation temperature. In the MK 45, available capsules provide approximately:

• H: 5 K subcooling.
• N: 10 K subcooling.
• U: 30 K subcooling.

The capsule should not be exposed to superheated steam above 5 °C.

Versions and Connection

• MK 45 / MK 45A: PN40 / Class 300, DN15–DN25.
• MK 45-1 / 45A-1: double seat for small flows.
• MK 45-2 / 45A-2: single seat for larger flows.
• Available connections: flanges EN 1092-1, ASME B16.5, BSP, NPT, socket weld EN 12760 / ASME B16.11, and butt weld EN 12627 / ASME B16.25.

Materials and Limits

The MK 45 features a body/cover made of 1.0460 or SA105, while the MK 45A uses stainless steel 1.4404 or SA182 F316L. The capsule is Hastelloy, and internal parts are made from special steels. For PN40, body limits reach 40 bar at 20 °C, reducing to 17.1 bar at 420 °C. The maximum operating differential pressure is 32 bar.

Application Selection

The MK is selected when automatic venting, backpressure resistance, and controlled condensate subcooling are required. For heat exchangers where condensate backing-up is unacceptable, a float steam trap is preferred.

Maintenance

The integrated Y-type strainer protects the seat and capsule. Key spare parts include the capsule, nozzle insert, filter, and graphite/CrNi gaskets.