Mortar silo or big bag?

The three in the catalogue

• ST-3 — 2.5 tonnes of dry mortar, can be mounted on the SST 1 stand with telescopic legs, funnel and slide gate
• ST-5 — 1 600 litres, equivalent to 2.5 tonnes, unladen weight 450 kg, 200–400 kg/min
• TB 10 — 6.5 m³, equivalent to 10 tonnes, unladen weight 1 100 kg, 200–400 kg/min

The output is the same

Note that ST-5 and TB 10 are rated at exactly the same output: 200–400 kg/min. So the large silo does not feed the pump any faster than the small one — it just holds four times as much before it needs refilling.

So the question is not how fast you need the mortar, but how many refills you want on the job. It is a logistics decision, not a performance decision.

Overall height is often decisive

ST-5 is a big bag emptier with a discharge screw and a low overall height, which according to Ahlm makes it particularly suitable indoors or where headroom is limited.

TB 10 holds 6.5 m³ and weighs 1 100 kg empty. According to Ahlm's brochure, it is 3.85 m long, 1.90 m wide and 2.90 m high.

Power and handling

ST-5 is specified as 3-phase, either 400 V or 220 V, 50 Hz. For TB 10, Ahlm's brochure gives a 2.2 kW electric motor and a 16 A, 5-pin CEE connection.

ST-3 and ST-5 are handled with a container truck, forklift or construction crane. That determines where they can be placed, and whether they can be moved during the project.

Both are dust-tight. Ahlm states that its silo products have a conical outlet with a vibrating beam for complete emptying, but on the ST-5 the vibrator is an option used to make emptying easier. On the TB 10, the vibrating beam is built into the conical lower section, and according to Ahlm this design prevents blockages.

The silo must suit the pump

Check that the output of 200–400 kg/min suits the machine the silo is to feed, and sketch the filling height of the machine and where the silo can stand in relation to it before ordering either. See the guide to choosing a mortar pump for that side of things.