Pump trap - APST | ADCA

ADCA ADCAMat APST Automatic Pump-Trap

The APST is an automatic pump-trap designed for the drainage and lifting of condensate from heat exchangers, coils, heating vessels, and closed return systems. It integrates a float steam trap mechanism and a pressure pump within a single body. When differential pressure is sufficient, it operates as a steam trap; under stall conditions, the pumping function is activated using motive steam.

Technical Specifications

• Sizes: DN 50 x 50 and DN 80 x 50
• Versions: APSTS carbon steel, APSTSS stainless steel, HC for increased trap capacity
• Connections: EN 1092-1 PN 16, ASME B16.5 Class 150, ISO 7 Rp with threaded flanges
• Motive Medium: saturated steam
• Motive Pressure: 1–10 bar
• Operating Temperature: 0–185°C
• Pump Displacement: approximately 22 L per cycle
• Minimum Liquid Density: 0.80 kg/L

Performance and Operating Limits

In pump mode, with a filling head of 300 mm, the flow rate depends on motive steam pressure and total backpressure. For a total backpressure of 0.35 bar, flow rates reach up to 3970 kg/h for DN 50 x 50 and 4580 kg/h for DN 80 x 50. In steam trap mode, standard versions reach up to 16000 kg/h, while HC versions reach up to 30000 kg/h at 10 bar differential pressure.

Materials and Sealing

The body is available in carbon steel or AISI 316/316L. Functional parts, seats, valves, floats, and the steam trap mechanism are stainless steel. Springs are Inconel, and gaskets are stainless/graphite. Check valves are A351 CF8M / 1.4408.

Applications

• Exchangers with modulating steam valves
• Installations where steam pressure drops below backpressure
• Condensate return networks with elevation
• Closed systems requiring a receiver for temporary storage during the pumping cycle

FAQ

When is APST chosen over a simple steam trap?
When there is a possibility of stall and the steam trap cannot evacuate condensate at low load.

Is electrical power required?
No. Operation is mechanical, using motive steam.

What data is required for selection?
Condensate load, steam pressure, total backpressure, secondary fluid temperatures, and available filling head.