Condensate Management

Mechanical Float Drain

Condensate drained by the liquid itself: no power, nothing to set, and no compressed air lost.

Download brochure Download questionnaire
A mechanical float drain with a rounded silver float chamber and a black inlet and outlet block

Product overview

A drain that runs on buoyancy

Our mechanical float drain uses the buoyancy of a float to drain condensate from your compressed air equipment. As liquid collects in its small chamber it lifts the float, and the float opens the discharge valve. As the level falls, the float drops and closes the valve before the liquid uncovers the seat.

The seat always sits under a column of liquid, so condensate leaves and compressed air stays in your system. The only gas lost is the air dissolved in the condensate, about 0.15 litres of free air per litre at 7 bar g and 20 °C.

It needs no electrical supply, cabling or signal connection: the liquid provides the actuating force and system pressure the discharge force. That makes it a natural fit for hazardous areas, outdoor pipe racks, mobile compressors, remote drip legs and filter housings.

A mechanical float drain with a rounded silver float chamber and a black inlet and outlet block
  • About 0.15 LFree air lost per litre of condensate
  • About 250 L/hThrough a 2 mm orifice at 7 bar g
  • More than 10 ×The aftercooler load in hot, humid conditions
  • ZeroPower supply or cabling needed

Benefits

The problems it solves

Condensate forms around the clock, often far from a power supply. Here is what goes wrong at drain points, and how the float drain deals with it.

  • Air lost at drains

    The problem

    A 3 mm orifice left open at 7 bar g passes roughly 30–40 m³/h of free air, around 30,000 kWh a year from a single drain stuck open.

    How it solves it

    The water seal above the seat keeps air in your system, and only dissolved air leaves with the condensate.

  • No power at the drain point

    The problem

    Drip legs on outdoor mains, receivers on roofs and filters inside machines often have no electrical supply, and cabling dozens of points is costly.

    How it solves it

    The drain needs no cabling at all, and keeps working through power failures.

  • Hazardous zones

    The problem

    In ATEX and IECEx zones, electrical equipment needs certification.

    How it solves it

    With no electrical ignition source, float drains are fitted in ATEX and IECEx zones.

  • Loads that swing

    The problem

    Condensate load swings from a humid afternoon to a dry night or a shutdown.

    How it solves it

    Opening and closing levels are fixed by the float geometry, so the drain follows the load in summer and winter alike and cannot be mis-adjusted.

  • Flooded dryers and filters

    The problem

    A liquid slug entering a dryer exceeds its moisture capacity and raises the outlet dew point, and coalescing elements standing in liquid pass oil and water downstream.

    How it solves it

    Continuous drainage keeps slugs and flooded bowls away from your downstream treatment stages.

  • Corroded receivers

    The problem

    Water standing on the base of a steel vessel corrodes the shell.

    How it solves it

    Your receivers stay free of standing water.

Where it’s used

Wherever power is hard to reach

Float drains serve every collection point in a compressed air system, and come into their own where running a power supply is impractical.

  • Test tubes of coloured chemicals in a laboratory rack

    Oil, gas and petrochemicals

    Non-electric drains on instrument air separators and drip legs inside ATEX and IECEx hazardous zones.

  • Electricity pylons and power lines at sunset

    Power generation

    Instrument and service air systems, including receivers outdoors on plant structures.

  • Wine bottles moving along a bottling line

    Food and beverage

    Drains on the coalescing filters that achieve the BCAS Guideline 102 classes for food-contact air.

  • Yellow tablets spilling from a medicine bottle

    Pharmaceuticals and healthcare

    Filter housings and receivers of production air and medical air plant.

  • Robots welding a car body on an assembly line

    Automotive and surface finishing

    Drip legs ahead of paint booths and blast rooms, before water reaches spray guns and blast nozzles.

  • A row of yarn winding machines in a textile mill

    Textiles

    Air-jet looms and spinning machines in humid halls, with heavy condensate loads in the network.

Also general manufacturing and engineering, mining, tunnelling and construction, rail and transport, water and wastewater treatment, plastics and packaging, and filter bowls in workshops and small plants.

How it works

Float, open, reseal

The liquid does the sensing and your system pressure does the pushing. No power, no timer, no settings.

How a mechanical float drain works: condensate runs by gravity from a filter, dryer or receiver into the float chamber while displaced air returns through a balance line; the rising liquid lifts a float on a lever, which pulls the plug off the valve seat so system pressure drives the condensate out, and as the level falls the float drops and reseats the plug while liquid still covers the orifice. No electrical supply is needed. Wet air inAir on to your plantFilter, dryeror receiverBalance line FloatLever and plug 2 mm seat · 2.2 N at 7 bar g No power needed Valve seat To oil–water separator≈ 250 L/h at 7 bar g Air lost ≈ 0.15 L/L 12345Wet compressed airDisplaced air returningCondensateYour equipment

  1. 1. CollectCondensate runs into the chamber by gravity, and the air it displaces returns through the inlet or balance line. The float rests low and the valve is shut.

  2. 2. RiseAs the level climbs, the float's buoyancy grows. At 7 bar g, pressure holds the plug on a 2 mm seat with about 2.2 N.

  3. 3. OpenThe float's lift, multiplied by the lever, exceeds the pressure force on the seat and the valve opens, with no electrical supply.

  4. 4. DischargeSystem pressure drives the condensate out. At 7 bar g a 2 mm orifice passes about 250 litres an hour.

  5. 5. ResealThe level falls, the float drops and the valve reseats while liquid still covers the orifice. Only air dissolved in the condensate is lost: about 0.15 litres of free air per litre.

Figures at 7 bar g, for a direct-acting drain with a 2 mm seat.

Get the full details

Our brochure covers it in detail, and our questionnaire tells us what we need to recommend the right one for your plant.

Download brochure Download questionnaire

Keep exploring

More from our range

Equipment for every stage of your compressed air, and our own engineers to test, commission and look after it.

Why Settle for Mediocrity When You Can Partner with the Best?

We are more than just another industrial solutions provider. We’re a partner in your success. With decades of experience and a team of experts dedicated to providing comprehensive solutions from equipment to service and sourcing, we’re confident in our ability to help you optimize your performance and achieve your business goals.

Speak with an Expert