7400 Automatic Isoperibol Calorimeter

The 7400 Automatic Isoperibol Calorimeter features a sleek modern design which includes a large, adjustable touchscreen display, upgraded CPU, and intuitive menu structure to maximize sample throughput in high volume laboratories.

Compact and self-contained, the calorimeter incorporates a closed-loop cooling subsystem. This subsystem uses a thermoelectric chiller assembly with 1 L water tank to supply cooling water to the calorimeter. 

The 7400 features a fixed vessel-and-bucket design, allowing for automated bucket and oxygen filling. The 7400 requires only one minute of operator time per test, allowing a technician to operate up to four calorimeters simultaneously. 

After each test is complete, the calorimeter automatically rinses the combustion vessel, readying the instrument for the next test.

Design Features

10-inch Adjustable Touchscreen Display

The 7400 Calorimeter is controlled by a high-resolution touchscreen with excellent touch accuracy and display clarity. The tiltable screen accommodates users and lab benches of any height. The durable, scratch-resistant, and shatterproof screen can be operated while wearing gloves or with protective film. 

Upgraded CPU and Software Interface 

A new CPU board and redesigned menu structure takes maximum advantage of the larger tablet-like display, allowing rapid and intuitive navigation. 

Fixed Quick Twist-Lock Vessel and Bucket 

The fixed combustion vessel and bucket makes it possible to offer a unique level of automation for the entire calorimetric determination process, not just data collection and reporting steps.

The patented “Quick Twist-Lock” closure of the 1138 Combustion Vessel allows the user to seal and lock the head into the cylinder with a simple one sixteenth turn. The main vessel seal is an O-ring optimized to minimize frictional wear, improving the lifetime of this seal. At the conclusion of the test, the inside surface of the vessel is washed to remove the products of the combustion from the vessel. The automation of the vessel washing step eliminates one of the most tedious and time-consuming manual operations required with removable vessel calorimeters. Besides the elimination of the drudgery of manually washing the vessel, a not so obvious advantage of the fixed vessel design is the washing of the vessel as soon as the final temperature can be determined. Generally, this is within 4-5 minutes of the time the vessel is fired. This holds to an absolute minimum the time any acids produced by the combustion can attach to the inner surfaces of the vessel. This has improved the service life of these vessels in comparison to removable vessels. 

The fixed bucket is designed to provide smooth circulation over the surface of the vessel. The design also repeatably fills the bucket volumetrically. The vessel head closure seals the bucket at the same time the vessel is closed. This unique design minimizes the amount of water required for each test, as well as permitting rapid, automatic, and repeatable filling for each test. The water heated by the combustion is automatically drained from the bucket at the conclusion of the test and replaced with cooling water to bring the vessel and bucket rapidly down to the starting temperature for the next test. 

Automatic Oxygen Fill 

The fixed vessel and bucket design allow the oxygen supply to be directed into the head of the vessel at the beginning of each test. The head of these vessels incorporate a check valve which dynamically seals when the vessel is pressurized. At the end of each test, the gases in the vessel are automatically released while the calorimeter is being returned to its starting temperature.

Vessel Wash Filter 

For studies involving samples with high ash content or incombustible inorganics, an optional vessel wash filter assembly can be added to the 1138 Vessel to protect the automatic mechanism from debris. 

1138 Oxygen Combustion Vessel 

The 1138 Oxygen Vessel installed in the 7400 Calorimeter is made from alloy 20, a special niobium stabilized stainless steel selected for its resistance to the mixed nitric and sulfuric acids produced during the combustion process. The 1138CL is made from the halogen resistant Hastelloy G30™. Hastelloy G30™ is an alloy rich in cobalt and molybdenum and can resist the corrosive effects of free chlorine and halogen acids produced when burning samples with significant chlorine content. While no alloy will completely resist the corrosive atmospheres produced when burning samples containing halogen compounds, users who intend to test these materials are urged to select the 1138CL Vessel. 

These vessels are 250 mL in volume and are rated to a working pressure of 2000 psi. The vessels are hydrostatically tested to 3000 psi and the sample range is ~1g releasing up to 8000 calories per test. 

A1450DD Head 

Users who wish to achieve maximum throughput with their 7400 Calorimeters will want to purchase a spare A1450DD head for their calorimeter. This permits the next sample to be completely prepared and inserted into the vessel as soon as the current test is concluded. 

Control Charts 

A control chart is a graphical tool which can assist the user in determining whether or not their process is in control. Many standard methods will dictate that a reference sample be measured periodically and the results plotted on a graph. Limits for acceptable values are defined and the process is assumed to be in control as long as the results stay within these limits. Since results are expected to scatter with a normal distribution within established limits, systematic trends or patterns in the data plots may also be an early warning of problems. The 7400 Calorimeter provides the user with the ability to instantaneously plot and view standard results with user defined warning and control limits.

Laboratory Requirements

The calorimeter requires a source of 99.5 percent oxygen, a source of nitrogen or house air at 80 psi, and deionized water.