The prefab digester steel tanks are calculated and offered according to one of the following standards:
EN, AWWA D103-87, API, BS, etc.

Tank type: prefab steel
Designed as cylindrical prefab steel tank bolted together from steel plates, bolts, nuts and washers. The sheets can be black steel, epoxy coated, glass coated or made from stainless steel.
The digesters can be made up to a 8.000M³ capacity with a max. diameter of 22 meters.
The working pressure are from design pressure -5 / + 50 mbar and working pressure of +30 mbar and design temperature of -20 C / +60 C.

Floor type
Standard built on prepared concrete slabs. After the tank erection, the tankwall can be concreted in or placed directly on the existing slab, depending on the tank and concrete design.

Protecting concrete slab
The concrete slab where the tank is built on can be protected against agressive chemicals by the Prefab epoxy or glass coated or stainless steel floor.

Sealing
Sealing is brought about by applying mastic on the edges and in between the excentric connection of the epoxy coated or stainless steel sheets on the in- and outside of the tanksheets and between the tankwall and (concrete or steel) floor.

Bolt types
On the inside of the tanks the hot-dipped galvanised flat bolt heads or stainless steel are covered by a medium resistant plastic cap (LDPE or PVDF). On the outside the nut and washer are covered by a weather and UVradiation-resistant LDPE cap.

Sealant
1 Or 2 component mastictypes, with high chemical resistance and adhesion porperties, longterm resistance to actual chemical and temperature attack. Chemical resistance listst are available.

Steel roof
Depending on diameter and the inside pressure the roof is made as a normal or heavy duty designed prefab roof from prefab stainless steel plates or epoxy coated plates. The roof has a slope of 20 degrees.
In the middle a heavy duty mixerflange can be placed to hold the central mixer.

Mixer
on top of the roof a mixerflange can be placed to hold a vertical mixer. Around the roof is a working platform and a walkway towards the mixer.

Accesoires
the accesoires are sight glasses; over- and under pressure valve; walkway and platform; manway; cageladder or spiral stair.

Insulation
it is possible to insulate the tank along the tankwall and on the roof with insulation. Tank shell by Mineralwool with trapezoid cladding sheets, RAL colour to be defined.
Roof will be flat cladding sheets.

If there are any questions or remarks please contact us at info@isstanks.com or give us a call at 0031 (0)512 – 58 20 58