The BOA-311 is Yamato's large-capacity constant-temperature oil bath — an ~37 L stirred oil bath with a built-in vertical propeller stirrer for uniform circulation, a 270 °C control ceiling, and a 4.5 kW heater. Where the small BOG/BOS baths handle a single flask, the BOA-311 immerses racks of vessels, large batches, or bulky fixtures at tightly controlled temperature. It runs on 200/220V single-phase and ships with an external step-up transformer for North American 115V supply (the 100 V / 200 °C sibling is the BOA200 series).
Key Specifications
| SKU | BOA-311 |
| Type | Large-capacity constant-temperature oil bath, stirred, digital PID |
| Bath capacity | ~37 L (oil level ≤50 mm from top edge); effective ~31.9 L with lowest shelf installed |
| Temperature control range | Room temp. +10 °C to 270 °C |
| Temperature control accuracy | ±0.1 °C (200 °C silicone oil) |
| Temperature distribution accuracy | ±0.3 °C (200 °C silicone oil) |
| Control system | PID controller, platinum (Pt) sensor, digital ▲▼ set, 0.1 °C resolution |
| Heater | SUS316 pipe heater, 4.5 kW |
| Stirrer | Vertical propeller, 25 W induction motor |
| Bath dimensions | ~440 W × 460 D × 320 H mm |
| Effective internal dimensions | ~293 W × 340 D × 270 H mm (top edge to lowest shelf) |
| External dimensions | ~531 W × 520 D × 578 H mm (bath height 397 mm) |
| Weight | ~37 kg |
| Voltage / power | 200V AC single-phase, 23 A (with external transformer) |
Application Profile
The 37 L stirred oil bath serves batch and fixture-scale high-temperature immersion work that exceeds a flask bath:
- Batch heating of multiple vessels — racks of tubes, flasks, or samples held together at one set point
- Viscosity, aging, and materials conditioning at temperatures to 270 °C
- Component and fixture immersion — heat treatment or conditioning of parts too large for a benchtop bath
- Calibration and reference heating where the ±0.3 °C distribution and stirrer-driven uniformity matter across a large volume
- Production and pilot-line constant-temperature processes needing sustained high-temperature oil heating
The vertical propeller stirrer is the key to uniformity: circulating the oil is what holds ±0.3 °C distribution across a 37 L bath, far tighter than an unstirred reservoir could achieve at this scale.
Design Architecture
A PID controller with a platinum sensor and 0.1 °C setting resolution drives a 4.5 kW SUS316 pipe heater, while a 25 W induction-motor vertical propeller continuously stirs the oil for even heat distribution. Temperature, set point, and the overheat-prevention screen read out on a 7-segment LED. Safety is layered and substantial for the wattage: an earth-leakage breaker with test lead, self-diagnostic sensor- and heater-failure detection, a key-lock, automatic overheat prevention (auto-recovery at set point +6 °C), and an independent overheat prevention device fixed at 300 °C. A drain cock, alarm output terminal, and a 4-20 mA / 1-5 V temperature-record output support integration into monitored processes. Because the unit is 200/220V single-phase at 23 A, it is supplied with an external step-up transformer for 115 V facilities — factor its footprint and the circuit rating into installation planning.
Frequently Asked Questions
What is the bath capacity of the BOA-311? About 37 L (oil filled to ≤50 mm from the top edge), or roughly 31.9 L effective with the lowest shelf installed.
What temperature range and uniformity does it deliver? Room temperature +10 °C to 270 °C, with ±0.1 °C control accuracy and ±0.3 °C temperature-distribution accuracy (at 200 °C with silicone oil).
How does it hold uniformity across such a large bath? A built-in vertical propeller stirrer driven by a 25 W induction motor continuously circulates the oil, which is what holds ±0.3 °C distribution across the 37 L volume — far tighter than an unstirred reservoir at this scale.
What power does it require? 200/220V AC single-phase at 23 A, supplied with an external step-up transformer for 115V facilities. The 100V / 200 °C sibling is the BOA200 series.
Is oil included? No. Fill with a suitable silicone/heat-transfer oil to ≤50 mm from the top edge (~37 L) — oil is not supplied.
Ordering & Configuration
In the box: shelf, cover, external step-up transformer, and instruction manual.
Add oil separately. Fill with a suitable silicone/heat-transfer oil (Yamato rates performance with silicone oil) to ≤50 mm from the top edge (~37 L) — oil is not included. Confirm oil selection for the intended set point.
Plan the electrical install. The bath draws 23 A at 200V single-phase through its external transformer — confirm circuit capacity and receptacle before delivery.
Confirm bench/floor space and ventilation. At ~531 × 520 × 578 mm and ~37 kg (plus transformer and oil), the BOA-311 needs a dedicated, well-ventilated station away from other heat sources.
Confirm at quote: supply voltage/circuit and transformer configuration, oil selection, shelving/accessory needs, intended process temperature, and lead time.
Warranty: Per Yamato standard capital-equipment terms — confirm at quote.
Yamato BOA large-capacity oil bath family:
- BOA200 series — ~37 L, 100V, Room temp +10 to 200 °C, 2 kW heater
- BOA-311 (this product) — ~37 L, 200/220V, Room temp +10 to 270 °C, 4.5 kW heater, with external transformer
