GESTRA BK 45, BK 45-U, BK 45-LT, and BK 46 are high-performance bimetallic steam traps from the RHOMBUSline, designed for discharging condensed water and air-venting steam lines. These robust traps are equipped with a corrosion-resistant stainless steel Thermovit regulator that ensures automatic air-venting during plant start-up and operation. The series is suitable for pressure ratings up to PN 40 or Class 300 and offers versatile end connections including flanges, weld ends, and screwed sockets.

Task and Function

The primary purpose of the BK series is to discharge condensate and vent air from steam systems efficiently. When the plant is started, the trap is fully open, allowing cold condensate and air to escape. As the media temperature rises, the bimetallic plates within the Thermovit regulator deflect, pulling the stage nozzle into the closing position. The orifice closes immediately below the saturation temperature, supported by thermodynamic processes in the stage-nozzle chamber.

Opening Temperatures

• Standard Adjustment: Approx. 15 K undercooling (Standard for BK 45 and BK 46).
• Special Adjustment (U): Approx. 30 K undercooling (Indicated by code letter "U" on the name plate for BK 45-U).

Equipment Specification

The BK 45 series features a modular design for easy maintenance and component replacement. Below is the detailed breakdown of the equipment components:

No.	Designation	No.	Designation
1	Name plate	6	Body
2	Plug	7	Flow arrow
3	Cover	8	Strainer
4	Thermovit regulator	9	Gasket
5	Cover gasket	10	Sealing plug

Technical Data

Materials

Component part	BK 45 / BK 45-U (DIN/ASME)	BK 45-LT (ASME)	BK 46 (DIN/ASME)
Body and cover	1.0460 / SA105	SA350 LF2	1.5415 / A182 F1
Bolts	1.7225 / A193 B7	A193 B7	1.7225 / A193 B7
Gaskets	Graphite/CrNi	Graphite/CrNi	Graphite/CrNi
Internals	Stainless steel	Stainless steel	Stainless steel

Dimensions and Weights (Flanged Ends)

Nominal Size DN	15 (1/2")	20 (3/4")	25 (1")
Overall Length (L) [mm]	150	150	160
Weight [kg]	3.7	4.3	4.8

Installation and Maintenance

For optimal performance, GESTRA recommends installing the equipment with the strainer insert hanging downwards. This orientation ensures that foreign matter is effectively trapped without impairing the valve function.

Performance Monitoring

Operation can be monitored using the GESTRA VAPOPHONE® ultrasonic test device or continuous condensate monitoring equipment for critical applications.

Troubleshooting

Problem	Cause	Remedy
Trap is cold	Shut-off valves closed	Open shut-off valves
Live steam blowing	Regulator contaminated/worn	Clean or replace Thermovit regulator
Leakage	Defective gasket/corrosion	Replace gasket or check material resistance
Insufficient discharge	Undersized trap/high back pressure	Check sizing or increase differential pressure