A steam trap discharging to atmosphere does not experience back pressure. Or does it?

Back pressure is the pressure on the outlet side of a steam trap. As this pressure increases, the differential pressure across the trap decreases, reducing its ability to discharge condensate. Even when a trap discharges to atmosphere, restrictions in the downstream piping such as elbows, tees, or valves may still create back pressure.

Every steam trap has a maximum allowable back pressure (MABP), the highest outlet pressure at which the trap can still function normally, expressed as a percentage of the trap inlet pressure. What many steam users do not realize is how much this limit can vary between trap types.

Read on to learn which system configurations create back pressure, how it affects trap discharge capacity, and how MABP differs depending on the type of trap.

Free Float® Steam Traps 
for Mid to High Pressure Applications

In applications where back pressure can approach inlet pressure, many traps may cycle erratically or stop operating altogether. TLV’s Free Float® JH Series steam traps are designed to maintain stable operation even under demanding mid- to high-pressure conditions.

With MABP of up to 90% of inlet pressure, the JH Series provides reliable condensate discharge in applications where thermodynamic disc traps may struggle. Continuous condensate drainage, powerful automatic air venting, and durable cast steel construction make these traps well suited for high temperature, high pressure steam processes.