Liquid tank ST series

stainless steeltransfermixing

Product overview
A chocolate holding tank keeps liquid chocolate at a stable working temperature and supplies downstream equipment continuously. It receives product from a ball mill, from a conche when conching is required, or from a melting tank, then feeds tempering, enrobing, depositing or molding. Required buffer volume, input state and available electrical supply determine the model.

Process suitability

• Use as a temperature-controlled buffer for liquid chocolate feeding downstream machines.
• Not a substitute for a melting tank when batch melting of solids is the primary process; staged top-up of solids is supported on selected models only.
• If required holding capacity exceeds 3000 kg, a single ST tank cannot be used; consider multiple tanks in rotation.

Available models and nominal capacities

• ST100 — 100 kg
• ST200 — 200 kg
• ST400 — 400 kg
• ST600 — 600 kg
• ST1000INS — 1000 kg (insulated)
• ST2000INS — 2000 kg (insulated, liquid input only)
• ST3000INS — 3000 kg (insulated, liquid input only; ships horizontally)

Input state rules

• Liquid input only models: ST2000INS and ST3000INS accept liquid chocolate only and do not accept solids; an upstream melting tank is required if incoming product is solid.
• Occasional staged solid top-up (maximum 25% of nominal capacity per charge) is accepted by ST100, ST200, ST400, ST600 and ST1000INS with specified per-charge limits (ST100: 25 kg; ST200: 50 kg; ST400: 100 kg; ST600: 150 kg; ST1000INS: 250 kg). The next charge may be added only after the previous charge has melted.

Insulation

• Non-insulated single-wall, water-jacketed models: ST100 / ST200 / ST400 / ST600 (up to 600 kg).
• Insulated models (glass wool between reservoir wall and outer casing): ST1000INS / ST2000INS / ST3000INS (above 600 kg) to reduce heat loss and lower heater cycling.

Model comparison (summary)
Model | Capacity | Power | Supply | Insulation | Occasional solid top-up (max per charge) | Eliminates if...
ST100 | 100 kg | 2.4 kW | 220 V / 1-phase | None | ≤25 kg per charge | Required holding capacity exceeds 100 kg or 220 V single-phase is unavailable
ST200 | 200 kg | 3.8 kW | 220 V / 1-phase | None | ≤50 kg per charge | Required holding capacity is ≤100 kg or >200 kg or 220 V single-phase is unavailable
ST400 | 400 kg | 4.5 kW | 220 V or 380 V | None | ≤100 kg per charge | Required holding capacity is ≤200 kg or >400 kg
ST600 | 600 kg | 5.5 kW | 220 V or 380 V | None | ≤150 kg per charge | Required holding capacity is ≤400 kg or >600 kg (no larger non-insulated model exists)
ST1000INS | 1000 kg | 12.7 kW | 380 V / 3-phase | Glass wool | ≤250 kg per charge | Required holding capacity is ≤600 kg or >1000 kg or 380 V three-phase is unavailable
ST2000INS | 2000 kg | 12.7 kW | 380 V / 3-phase | Glass wool | Not accepted — liquid input only | Required holding capacity is ≤1000 kg or >2000 kg or incoming product is solid without upstream melting tank or 380 V three-phase is unavailable
ST3000INS | 3000 kg | 12.7 kW | 380 V / 3-phase | Glass wool | Not accepted — liquid input only | Required holding capacity is ≤2000 kg or >3000 kg or incoming product is solid without upstream melting tank or 380 V three-phase is unavailable


Configuration options (select as required)

• Automated heated valve for selecting recirculation loop or external transfer — required when automatic switching between recirculation and transfer is needed; if omitted, automatic switching and valve-seat heating are not provided.
• Water-jacketed chocolate inlet assembly for an upstream pump — required when an upstream pump feeds the tank through fixed piping; if omitted, the tank must be charged by hand.
• Product level sensor (stops the upstream pump before overflow) — available for all models (requires inlet assembly); without it, unattended filling can overflow the tank.
• External cooling-water control solenoid valve — available on ST100, ST200, ST400, ST600 to support automatic cooling for batch-tempering; if omitted, cooling must be controlled externally.
• Load-cell weighing system — available on ST1000INS, ST2000INS, ST3000INS for accurate bulk dosing by mass; if omitted, transfer cannot stop automatically by measured mass.
• Flowmeter — available on ST1000INS, ST2000INS, ST3000INS as a lower-cost bulk dosing option with reduced accuracy; if omitted, transfer cannot stop automatically by measured flow.

Working principle
Liquid chocolate enters the water-jacketed reservoir from a refiner, conche or melting tank. PID-controlled jacket heating holds the setpoint. Variable-speed agitation with sidewall scrapers prevents sedimentation, distributes heat evenly and prevents cocoa butter migration. Integrated transfer pump (gear pump on ST100–ST600; lobe pump on insulated models) feeds downstream equipment continuously while the tank accepts further upstream batches.

Operating and process constraints

• Holding temperature is recipe-bound: typical starting ranges — dark couverture 45–50 °C; milk and white couverture 40–45 °C; compound coatings on palm/kernel fat 48–51 °C. Keep mass fully melted without prolonged overheating.
• Agitation must run continuous or intermittent while chocolate remains in the tank to avoid sedimentation and viscosity stratification; do not leave agitation off permanently when product is present.
• Bypass return flow from tempering machines must be reheated (use a decrystallization tube) before re-entering the tank to avoid cooling the bulk mass and destabilizing downstream tempering.

Maintenance, cleaning and warranty notes

• Use 30% food-grade inhibited propylene glycol in the water jacket (or heat-transfer fluid as specified) to prevent scale and mud build-up from untreated hard water.
• Inspect pump seals regularly (gear-type on ST100–ST600; lobe-type on insulated models) and check spring-loaded Teflon sidewall scrapers for wear.
• Do not flush with water for cleaning high-cocoa-content chocolate. Pump out residual chocolate, flush with warm cocoa butter or a food-grade fat-based flushing medium at holding temperature, pump out and wipe inner surfaces.
• Warranty: 1 year against manufacturing and construction defects. Typical lead time: 3–4 months, units built to capacity, voltage and piping specification.

Possible upstream and downstream connections

• Upstream: ball mill refiner, liquid chocolate conche (when conching is required), or chocolate melting tank (when production starts from solids).
• Downstream: tempering machine, enrober, depositor or molding line. Integrated pump can feed at any fill level above pump inlet.

caractéristiques / spécifications techniques

• Range of nominal capacities: 100–3000 kg (ST100 to ST3000INS).
• Construction: AISI 304 stainless steel reservoir and components.
• Heating: water-jacket with PID-controlled heating element.
• Insulation: glass wool on INS models (ST1000INS, ST2000INS, ST3000INS); non-insulated single-wall on smaller models.
• Agitation: variable-speed, continuous or intermittent; sidewall scrapers (spring-loaded Teflon).
• Integrated transfer pump: gear-type (ST100–ST600); stainless steel lobe-type (INS models).
• Electrical supply and installed power by model: ST100 220 V 1-phase 2.4 kW; ST200 220 V 1-phase 3.8 kW; ST400 220/380 V 4.5 kW; ST600 220/380 V 5.5 kW; ST1000INS 380 V 3-phase 12.7 kW; ST2000INS 380 V 3-phase 12.7 kW; ST3000INS 380 V 3-phase 12.7 kW.
• Maximum staged solid-charge per model (where allowed): ST100 25 kg; ST200 50 kg; ST400 100 kg; ST600 150 kg; ST1000INS 250 kg; ST2000INS and ST3000INS do not accept solids.
• Typical holding temperature guidance: dark couverture 45–50 °C; milk/white couverture 40–45 °C; compound coatings 48–51 °C.
• Optional measurement and control: inlet assembly, level sensor, automated heated valve, cooling-water solenoid valve, load-cell weighing system, flowmeter.