A South Australian cheese maker wanted 30,000 to 34,000 litres of outdoor milk storage. Simple enough, until you look at the site: a 4.8 m awning overhead, an existing 3.2 m plinth underneath, and a silo that had to stand on legs. Those three things set the ceiling on what any tank could hold, and the job became squeezing every usable litre out of a fixed space.
The limits
| Constraint | Limit | What it meant |
|---|---|---|
| Height | 4.8 m, under an awning | Caps the straight side once the legs and both cones are allowed for |
| Footprint | Existing 3.2 m plinth | Shell diameter set at 3,150 mm, with the legs landing on the plinth |
| Support | Must stand on legs | A cone bottom drains fully, but takes height without adding much volume |
| Location | Outdoors | Weather-protected venting, insulation and stainless cladding |
With the diameter and the height both fixed, the volume had to be worked out from them.
Three rounds in 3D
We modelled the silo in 3D and checked its volume in CAD at every step.
| Stage | Shell | Straight side | Overall height | Volume |
|---|---|---|---|---|
| Concept sketch | 3,000 mm | 4,000 mm | 4,800 mm | 29,214 L total |
| Proposed scope | 3,150 mm | 3,850 mm | 4,800 mm | 30,500 L working |
| Final build | 3,150 mm | 3,750 mm | 4,700 mm | 29,700 L working |
Working volume is measured to 100 mm below the top of the straight side, which leaves room for agitation and CIP. At 3,150 mm across, every 100 mm of straight side holds about 780 litres. Trimming the final 100 mm to keep the tank clear of the awning cost roughly 800 litres.
We told the customer straight: 34,000 litres wasn’t possible on legs within these limits. We offered a sloping flat-bottom alternative, which would win volume back if the plinth could be given a fall, and let them weigh it up.
The silo we built
| Item | Specification |
|---|---|
| Working volume | 29,700 L |
| Shell | 3,150 mm diameter × 3,750 mm straight side |
| Overall height | 4,700 mm, on 6 legs |
| Base | Cone bottom for full drainage, on a 3,200 mm plinth |
| Agitation | Sanitary side entry agitator |
| Access | Side entry manway |
| Cooling | 1,200 mm band of dimple plate on the bottom strake |
| Connections | 3″ BSM inlet and 3″ BSM outlet |
| Venting | 6″ vent in the top cone |
| Cleaning | CIP sprayball through the top cone, piped down the outside to 1,500 mm off the floor |
| Level control | High-level probe, side-mounted near the top |
| Insulation | 50 mm polystyrene, clad in stainless steel sheet |
Built for dairy hygiene, outdoors
Every stainless component, cladding included, is 316 grade, for corrosion resistance outdoors and against dairy cleaning chemicals.
- Internal finish: all internal welds ground flush and strip polished to 180 grit, so milk solids have nowhere to lodge
- Cleaning: the cone bottom drains completely, and the fixed CIP sprayball covers the vessel without anyone climbing inside
- Temperature: the dimple plate cools the milk at the base, where the agitator keeps it moving past the chilled wall, and the insulation holds temperature against the sun
- Overfill: the high-level probe signals before the milk reaches the top of the working volume
The silo left our Minto workshop finished and ready to set on its plinth, and the customer’s own team installed it.
Why it matters
The best tank is the one that fits the site you’ve got. We started from the awning, the plinth and the legs, then showed the customer exactly how much milk that space could hold and what the alternatives would gain.
Got a tight site, an odd footprint or a plinth to reuse? Read our stainless steel silo design guide, see our dairy processing equipment, or talk to us early and we’ll model your vessel in 3D before anything is built.
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Tight room, low ceiling, a plinth to reuse? Send us the limits and we’ll model the vessel in 3D before anything is built. See our dairy processing equipment or contact us.