Hart Scientific 7321 - Deep-Well Compact Bath (–20 °C to 150 °C)

Need a bath with a lot of immersion depth, great stability, and a low price tag? How about one that minimizes fluid costs, changes temperatures quickly, and runs quietly? 

Hart’s new Deep-Well Compact Bath series features four models covering temperatures from –80 °C to 300 °C. 

Each model includes a 457 mm (18-inch) deep tank to accommodate long-stem PRTs, SPRTs, and liquid-in-glass (LIG) thermometers. Access openings are 120 by 172 mm (4.7 in by 6.8 in) so you can calibrate many thermometers simultaneously. Yet only 15.9 liters (4.2 gallons) of fluid are needed to get all the benefits Deep-Well Compact Baths offer. 

Using Hart’s own best-in-class temperature controller, these baths deliver the performance you need for confidence in your calibrations. The 7381 (–80 °C to 110 °C) features both stability and uniformity better than ±0.007 °C over its entire range. The 7341 and 7321 (–45 °C to 150 °C and –20 °C to 150 °C, respectively) are stable to ±0.005 °C and uniform to ±0.007 °C at temperatures below ambient. And finally, the 6331 provides stability and uniformity from ±0.007 °C to ±0.025 °C over its range from 40 °C to 300 °C. 

Be sure to understand the performance of the temperature calibration equipment you buy. Some manufacturers offer only limited (and often difficult to interpret) specifications. The table at right includes stability and uniformity values for the entire range of each bath—and tells you what fluid we used in the measurements. If that’s still not enough, give us a call and we’ll be happy to explain anything—and share data with you. 

Hart’s control system automatically adds refrigeration when you need to cool down quickly, and shuts down refrigeration when you need to heat up quickly. For maximum stability, refrigeration levels are automatically balanced to match the set-point temperature you’re working at. 

Connect any of these baths to a Hart thermometer readout and Hart’s industry-leading MET/TEMP II temperature calibration software, and you’ll be performing automated probe calibrations within minutes from switch-on. 

Want to optimize your bath for calibrating liquid-in-glass thermometers? Simple. With the optional LIG Thermometer Calibration Kit, you get an easy-to-install fluid level adapter tube that raises the meniscus of the bath fluid to within about 12 mm (0.5 in) of the top surface of the bath itself. The kit also includes a thermometer carousel that fits onto the top of the fluid level adapter tube and holds up to ten LIG thermometers in place. A magnifying scope (8X) is also available that mounts to the front of any Deep-Well Compact Bath so you can clearly see the liquid level of your thermometer against its temperature scale. 

Like all Hart baths, these units come with a report of test that includes one hour of stability data and a verification of set-point accuracy. A convenient overflow reservoir captures any excess fluid resulting from fluid expansion, allowing the trapped fluid to be reused following subsequent fluid contraction. A drain is also provided for easily emptying the bath’s tank when needed.