Mechanical Pump Sets

Efficient condensate drainage is essential on all steam systems and the traditional method for this is the use of condensate steam traps.

For condensate drainage to be possible and effective, the differential pressure between the inlet and outlet pressures of the trap must be both positive and enough to overcome the static head pressure. Therefore, the upstream pressure must be greater than the sum of the downstream pressure and the condensate return system pressure drop.

Mechanical Pump Traps

However, in some cases, the pressure in the condensate return line is higher than the steam pressure and the steam trap does not therefore discharge condensate (or enough condensate), or primary control devices including control valves can cause a heat exchanger to stall and not return enough condensate. In these cases, and for efficient and reliable condensate drainage, a mechanical pumping trap or condensate pump can be installed for trapping at a lower upstream pressure than the one in the condensate return line.

This equipment can be easily installed and prefabricated if required; and their use can optimise plant efficiency and product quality throughout the process.


  • Low running and maintenance costs
  • Self-contained (no electrical supply required)
  • Ideal for humid/wet/remote applications
  • No cavitation
  • Fully automatic and self-regulating

How do they work?

Typically installed in ‘open’ steam systems, mechanical pump trap sets use incoming steam mains pressure as motive steam, which is let into the mechanical pump trap chamber. If the condensate level rises and is not discharged, the mechanism will lift in accordance with the float level, allowing higher pressure to enter and be used as motive pressure to return the condensate. The condensate on the mechanical pump trap will clear and the mechanism close, with the cycle then repeated as required.

  1. Condensate enters the pump chamber via the inlet swing check valve
  2. As water levels fluctuate, the float linkage opens the outlet valve and allows condensate to drain
  3. If condensate levels increase too much, motive steam is released into the pump chamber, forcing condensate through the outlet

Typical Applications

Typically installed in ‘open’ steam systems for condensate recovery, mechanical pump sets can also be used for condensate removal in closed systems and condensate removal for vacuum equipment.

From the Valveforce Range

Valveforce can supply and install the following equipment relating to Mechanical Pump Sets:-

  • Replacement Float Mechanisms
  • Insulating jackets and pipe insulation
  • Exd intrinsically safe versions for hazardous environments
  • Disc check valves and spare ancillary items
  • Complete packaged pumping systems


Our Valveforce engineers have the expertise to carry out the following work for your pump sets

  • Steam and condensate system audit
  • Design of new, packaged mechanical pumping systems
  • Complete mechanical turnkey installation
  • Hydro testing of assemblies/systems
  • Servicing and commissioning services

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Valveforce Ltd specifically work alongside BSi for all aspect of our company activities by installing a UKAS accredited quality system in accordance with the guidelines laid down in ISO 9001:2015.