Contact us


The oven heats 6 “bombs” in aluminium heating blocks. The heating blocks are mounted on a rotor that rotates at 20 rpm to ensure sample is constantly mixed. The digestion block temperature and bomb internal temperature of each individual bomb is measured and individually controlled. Heating is via 4 x 600W cartridge heaters.

Controller is a microprocessor controlled unit with a 16 bit analog to digital converter.

Program is up to 30 steps of ramp and hold and is held in non volatile memory (IE, retained despite power failure).


1)         BOMBS

            Constructed from solid 316 grade stainless steel. 10mm thick walls.

            Max Temp :                             300°C

            Max Pressure :                        90Kg/cm2  (vapour pressure at 300°C)

            Volume :                                  260mL total, sample 160mL to 200mL

2)         SENSORS

            PRD100 platinum resistance sensors with stainless steel sheaths.

3)         CONTROLLER           

            Microprocessor :                     87C51

            Temperature conversion :      Constant current driver with 16 bit converter.

            Temperature accuracy :         +/- 1°C

            Temperature control :             Proportional control via zero crossing solid state relays.

            Readout :                                Display is 2 line x 20 character LCD, showing temperature of each                                                             active bomb.

4)         SAFETY

            Controller:                               Contactor isolates heaters in the event of solid state relay failure.

            Bombs :                                  Clamp screws are designed to fail by stretching and releasing                                                             pressure well below bomb failure pressure.


The method of contact heating allows for rapid heating of sample as against air heated ovens and rates of faster than 5 seconds per °C are achieved. The unit operates from 3 phase power of 440V.

Pictured below is a pair of ovens installed at National Environmental Research Institute, Nagpur, India.

The controller is on top of the ovens. One digestion block has the cover removed and the bomb internal temperature sensor may be seen.


Page last updated March 2018