Calorimeter FAQs

Your ultimate guide to everything about calorimeters

Welcome to our Calorimeter FAQs page — your one-stop resource for learning everything about calorimeter types, uses, maintenance, and troubleshooting.

About DDS Calorimeters:

Who is DDS Calorimeters?

DDS Calorimeters designs and manufactures the CAL3K range of oxygen bomb calorimeter systems for over 40 years, trusted worldwide for accurate calorific value determination.

What is a bomb calorimeter?

A bomb calorimeter is a laboratory instrument that measures the heat released during combustion of a solid or liquid sample at constant volume.

What industries use DDS Calorimeters?

Our calorimeter systems are widely used in various applications & industries such as: fuel and oil analysis, coal and coke analysis, alternative energy research (biofuels), food & nutrition research, food quality control, animal feed research, waste management and recycling, steel and cement manufacturing, explosives and propellant testing, polymer and composite manufacturing, safety application, academic research, university applications: engineering, health sciences, agricultural sciences, animal sciences, food sciences, environmental sciences.

What models do you offer?

DDS manufactures five CAL3K calorimeter systems – from entry-level units for low sample throughput to fully automated systems requiring minimal operator input.

Choosing the Right Calorimeter Model:

Which CAL3K model is best if I test only occasionally / low throughput?

The best model for low sample throughput is the CAL3K-S entry level system.

Which model is best if I have high throughput?

The best model for high throughput will be the CAL3K-A and the CAL3K-AP system

Which model is best if I need automatic oxygen filling?

Our CAL3K-AP Calorimeter is the only calorimeter system we manufacture that has automatic oxygen filling.

How much difference in cost / performance between entry-level vs fully automated models?

The price difference does vary between our entry level system to our fully automated system. Our entry level system’s CAL3K-S and CAL3K-ST’s determination speed is reduced, allowing the operator to perform a new sample every 30 minutes. Where the higher end models such as the CAL3K-A and CAL3K-AP can achieve a new sample within 4-8 minutes.

If I run a sample every hour, when can I expect the result?

When the vessel is cold or in its ready state, a result can be expected with in 5-8 minutes between all calorimeter models.

Once the calorimeter has fired the vessel, the vessel needs to be cooled back down to its operating temperature.

Can I upgrade from manual to automated later?

No, we only have one fully automatic system, the CAL3K-AP which includes automatic oxygen filling and de-filling.

All our other models are semi-automatic and include manual oxygen filling. If you were to want to upgrade to fully automatic you would then need to purchase a new CAL3K-AP unit and vessels.

Sales & Purchasing our Calorimeters:

How do I request a quote?

Complete the Request a Quote form on our website and our sales team will contact you promptly.

Do you ship internationally?

Yes – DDS Calorimeters are exported worldwide, with agents in Africa, Europe, the Middle East, Asia, North & South America, and Australia.

How long is delivery lead time?

Typical lead time is 4–6 weeks, depending on model availability and order size.

Technical & Application:

What sample types can be tested?

Both solid and liquid samples can be tested, including fuels, food products, waste, and research samples. Our calorimeter systems do not test any gas products, only solid or liquid samples.

What is the typical determination time?

Determination time ranges from 5 to 20 minutes per sample, depending on the model you choose.

What is the difference between your models?

CAL3K-A: Top of the range model, higher throughput, fast and accurate, manual oxygen filling.
CAL3K-AP: Automatic oxygen filling and de-filling, high throughput.
CAL3K-F: Expandable system, best suited to University applications and others.
CAL3K-S: Entry level system, compact and highly accurate
CAL3K-ST: Entry level system, well suited to teaching and student-focused applications.

Support & Service:

Where are your systems manufactured?

All DDS systems are designed and manufactured in South Africa, with a worldwide network of agents.

Do you provide training?

Yes – we provide operator training, video tutorials, manuals, and ongoing technical support.

What warranty do your systems include?

Each calorimeter comes with a 12-month warranty, with options to extend depending on service agreements.

How can I order consumables and parts?

Consumables and spares are available directly from DDS or through our authorized agents.

Operation / Practical Usage of our Calorimeter Systems:

What sample mass (size) is appropriate for best results?

We recommend a sample mass of 0.5grams. This is the standard mass limit. However, it does depend on the sample type, some samples may require a lower mass and some a higher mass.

Our systems are set as default to a minimum mass limit of 0.2grams and maximum mass limit of 1gram. These limits can be changed to suit the sample type.

What are safety considerations when working with high-pressure oxygen?

Always conform to the industry standard of handling procedures for oxygen bottles. Make sure the bottle is securely fitted against a wall. Never use oil or oil based grease on any part of the gauge assembly or any part of the filling station and vessel.

Use only the DDS approved high-pressure grease supplied, if lubrication is required. Do not use a hammer to free a jammed valve. Use only an approved pressure reduction valve with a safety blow valve.

When in doubt, always consult with your safety engineer first.

What power requirements / lab space / utilities (ventilation / exhaust) are needed?

Our calorimeter systems require a AC mains outlet for the calorimeter and air cooler. The laboratory space does not need to be that large. Our calorimeter systems are desktop systems and require minimal space for set up. We do recommend good ventilation in the laboratory and an extended exhaust pipe to release any harmful gases after determination. The calorimeter should not be placed next to a heat source e.g. oven. Should not be in direct sunlight and not in the direct vicinity of an air conditioner.

Are there consumables / spare parts that need frequent replacement (e.g. ignition wire, bombs, crucibles)?

Yes, it is important to maintain the vessel and to change the consumables on a regular basis to keep the vessel in good working condition. We recommend checking the electrodes, deflector plate, firing wire, o-rings and crucible regularly for wear and tear and these consumables should be changed frequently.

How to prepare solid vs liquid samples properly?

Samples are all different but it is important to make sure that very little contact is made with the sample and your fingers (skin). Use the supplied stainless steel tweezer to place solid samples into the crucible and it is best to use a syringe to place liquid samples into the crucible.

Maintenance & Calibration of the Calorimeter:

How often should the calorimeter be calibrated?

A calibration can be performed every 2 weeks.

How do I maintain accuracy over time (cleaning, parts, calibration)?

Maintenance is key and daily maintenance schedules should be followed to keep the system functioning to its full potential and accuracy.

What is the repeatability / reproducibility of the CAL3K systems?

We confirm our systems have an RSD of 0.1%. Our CAL3K-S system can achieve an RSD of 0.05%

What are common sources of error (e.g. oxygen purity, sample prep, vessel leakage) and how to avoid them?

Lack of vessel maintenance can cause errors, to avoid misfires and oxygen leaks, be sure to check all o-ring regularly and to follow the maintenance schedules outlined in the manual.