A storage vessel that doses itself

No pump, no power, no calibration drift

A bladder tank is essentially a foam concentrate reservoir that uses incoming water pressure, rather than an electric pump, to push concentrate out toward the proportioner. Water enters the shell side and squeezes the bladder from the outside; as it collapses, concentrate is forced through the outlet at a rate matched to the water flow. The result is a proportioning system with very few moving parts - which matters in a tank room that may sit untouched between annual inspections.

The horizontal layout is chosen for installations where headroom is limited but floor footprint is available - pump houses, foam stations alongside tank farms, or retrofits into an existing equipment skid. Capacity, shell diameter, and nozzle layout are configured per project rather than sold off a fixed size chart.

2

How the shell and bladder divide the work

 

The shell carries the full design pressure of the water system and the static load of a tank that may hold several thousand litres of liquid. Carbon steel plate, rolled and welded to pressure-vessel practice, gives the wall thickness and weld integrity needed for that duty at a cost that keeps larger capacities economically viable - which matters because foam tanks scale up quickly on real projects.

The bladder never sees structural load; its only job is to keep two liquids apart without contaminating either one, while flexing through thousands of fill-and-discharge cycles over the tank's service life. That is a chemical-compatibility and flexibility problem, not a strength problem - which is why the bladder is a separate material choice from the shell, sized and selected against the specific foam concentrate it will hold.

 

 

3

Bladder material

 

 

 

Rubber or PVC - matched to the concentrate

PVC bladder

A PVC bladder is lighter, generally lower in cost, and easier to fabricate into custom shapes for non-standard tank geometries. It performs well in temperature-controlled indoor tank rooms and is commonly paired with synthetic or fluorine-free foam concentrates that are compatible with PVC sheeting. It is less suited to environments with large temperature swings or prolonged sub-zero exposure.

Rubber bladder

A synthetic rubber bladder, typically EPDM or NBR-based depending on the concentrate, offers strong flex fatigue resistance and holds its elasticity across a wider temperature range. It tends to be the default choice for outdoor installations subject to seasonal temperature swings, and for AFFF or protein-based concentrates where long-term chemical exposure data on rubber compounds is well established.