The Additel ADT 835-250 Portable Calibration Bath is a high performance portable liquid bath designed for precise temperature calibration in laboratories, quality assurance and on site applications. With a temperature range from 33 °C to 250 °C, a display accuracy of ±0.1 °C and excellent temperature stability, this compact liquid calibration bath is ideal for demanding calibration tasks involving a wide variety of temperature sensors.

Unlike conventional dry well calibrators, the liquid bath provides exceptional flexibility for accommodating temperature probes with different diameters, shapes and dimensions. The large 90 × 90 mm bath opening and maximum immersion depth of 155 mm provide excellent conditions for a wide range of devices under test. The Additel ADT 835-250 therefore combines the advantages of a precise liquid calibration bath with the mobility of a compact temperature calibrator.

As a specialist in calibration technology, europascal supports users in selecting suitable temperature calibration equipment and also provides professional Calibration Services for temperature and other measurement quantities.

Your Benefits at a Glance

• Temperature range from 33 °C to 250 °C
• High display accuracy of ±0.1 °C
• Stability of ±0.015 °C over 10 minutes
• External reference measurement accuracy of ±0.05 °C
• Large bath opening of 90 × 90 mm
• Maximum immersion depth of 155 mm
• Suitable for a wide variety of temperature probe sizes and geometries
• Fast heating and cooling for efficient calibration procedures
• Advanced dual zone heating technology
• Simple operation via a large color touchscreen
• Compact design for laboratory and mobile applications
• Communication via USB, LAN, WiFi and Bluetooth
• One touch self calibration for convenient workflows

Ideal for Demanding Calibration Applications

The Additel ADT 835-250 was developed for users requiring high accuracy, excellent temperature stability and maximum flexibility. Liquid calibration baths provide an important advantage for temperature calibration: the heat transfer medium surrounds the immersed sensors, providing excellent thermal contact.

Typical applications for the Additel ADT 835-250 include:

• Calibration laboratories
• Quality assurance
• Production facilities
• Research and development
• Pharmaceutical industry
• Process industries
• Energy supply
• Mechanical and plant engineering
• Service and maintenance
• Mobile temperature calibration

The portable calibration bath is particularly suitable for resistance thermometers, reference probes, industrial temperature sensors and other sensors where uniform temperature distribution and reproducible calibration conditions are essential.

The combination of compact dimensions and high performance makes the Additel ADT 835-250 suitable for both stationary applications and on site calibration. Users can perform precise temperature calibrations without requiring a large stationary liquid bath.

Flexible Configuration

The Additel ADT 835-250 can be flexibly adapted to different calibration tasks. Its large bath opening accommodates temperature probes with various geometries and diameters, providing a significant advantage compared with calibrators using fixed inserts.

For particularly demanding measurements, an external reference can be used. In combination with a suitable reference thermometer, the system provides an external reference measurement accuracy of up to ±0.05 °C. This makes the calibration bath suitable for high quality comparison calibrations.

Additel ADT 835-150 for Temperatures Down to −30 °C

For applications in the lower temperature range, the Additel ADT 835-150 is the appropriate alternative to the ADT 835-250.

While the ADT 835-250 covers a temperature range from 33 °C to 250 °C, the ADT 835-150 operates from −30 °C to 150 °C. The ADT 835-150 is therefore particularly suitable for calibration tasks requiring temperatures significantly below ambient temperature.

Both models feature a compact 90 × 90 mm bath opening and combine the flexibility of a liquid calibration bath with the mobility of a portable temperature calibrator. The appropriate model therefore primarily depends on the required temperature range.

The ADT 835-150 is recommended for applications from −30 °C to 150 °C, while the ADT 835-250 is the appropriate solution for higher temperatures up to 250 °C.

Both temperature ranges are also available as ADT 835PC versions. The PC models feature an integrated process calibrator and provide additional measurement capabilities for demanding calibration applications.

Additional solutions from the manufacturer are available in the Additel product overview at europascal.

Technical Highlights

• Temperature range: 33 °C to 250 °C
• Display accuracy: ±0.1 °C
• Accuracy with external reference: ±0.05 °C
• Temperature stability over 10 minutes: ±0.015 °C
• Temperature uniformity: ±0.03 °C up to 200 °C
• Temperature uniformity above 200 °C: ±0.04 °C
• Repeatability with internal reference: 0.04 °C
• Repeatability with external reference: 0.01 °C
• Heating time from 23 °C to 100 °C: approx. 20 minutes
• Heating time from 100 °C to 250 °C: approx. 35 minutes
• Cooling time from 250 °C to 100 °C: approx. 30 minutes
• Cooling time from 100 °C to 33 °C: approx. 45 minutes
• Bath opening: 90 × 90 mm
• Maximum immersion depth: 155 mm
• Bath volume: max. 2.5 liters
• Recommended heat transfer fluid: 50 cSt DOW CORNING XIAMETER PMX-200
• Weight without fluid: approx. 14 kg
• 6.5 inch color touchscreen
• Adjustable resolution down to 0.001 °C
• Interfaces: USB A, USB B, LAN, WiFi and Bluetooth

Technical Specifications

Why Choose the Additel ADT 835-250?

The Additel ADT 835-250 Portable Calibration Bath combines the excellent thermal performance of a liquid calibration bath with a compact and portable design. This combination is particularly attractive for users who regularly calibrate different temperature probes without sacrificing the flexibility offered by a liquid bath.

A major advantage is the generous working area. While many dry well calibrators require specific inserts for different sensor diameters, sensors of various sizes and shapes can be flexibly positioned in the liquid bath. This makes the instrument particularly suitable for applications involving frequently changing devices under test.

The excellent temperature stability supports reproducible measurement results. At the same time, rapid temperature changes allow multiple calibration points to be reached efficiently. According to the manufacturer, the Additel ADT 835-250 requires approximately 20 minutes to heat from 23 °C to 100 °C and a further approximately 35 minutes from 100 °C to 250 °C.

The modern user interface simplifies the configuration and monitoring of calibration tasks. A large color touchscreen provides a clear overview of important measurement values and instrument settings. Communication interfaces including USB, LAN, WiFi and Bluetooth also simplify integration into modern laboratory and calibration environments.

The Additel ADT 835-250 therefore provides a powerful solution for organizations seeking precise, efficient and reproducible temperature calibration.

Additel ADT 835-250 or ADT 835-150?

The Additel ADT 835 series provides two complementary temperature ranges for professional calibration applications.

The ADT 835-250 is designed for temperatures from 33 °C to 250 °C and is the appropriate choice for applications requiring higher positive calibration temperatures.

The Additel ADT 835-150 extends the operating range below ambient temperature and covers −30 °C to 150 °C.

Both models use the flexible liquid bath concept and provide a large 90 × 90 mm bath opening. This allows temperature probes with different diameters and geometries to be calibrated without requiring dedicated dry well inserts.

For applications requiring additional electrical measurement functions, both temperature ranges are also available as ADT 835PC Process Calibrator versions.

This product structure allows users to select the ADT 835 model that best matches their required temperature range and calibration workflow.

Typical Calibration Applications with the Additel ADT 835-250

The Additel ADT 835-250 is suitable for numerous applications in professional and industrial temperature metrology. These include comparison calibrations of resistance thermometers, industrial temperature probes and reference sensors.

The large bath opening also allows several sensors to be inserted simultaneously. This enables efficient comparison measurements and can reduce workload, particularly for recurring calibration tasks. Excellent temperature uniformity within the working area supports reliable and reproducible results.

For calibration laboratories, the instrument provides a compact alternative to larger stationary liquid baths. Service organizations and maintenance departments benefit from the portable design when calibration needs to be performed directly at customer sites or industrial installations.

europascal supports you both in selecting suitable temperature calibration equipment and in the regular verification of your measuring instruments. Information about accredited services and additional options is available from the europascal Calibration Service.

Detailed technical information about the Additel ADT 835-250 is also available on the official Additel ADT 835 product page.

Discover more Additel products here.

Manufacturer information about the Additel ADT 835-250 is available on the official Additel website.

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