High Pressure Vessels

Special Purpose Laboratory Pressure Vessels

Pressure vessels are generally tailor-made to customer specifications. We have made many specialized designs – from one with a ¼” bore by 2-½” long working cavity, to ones with a 21” bore and 72” between closures. However, over the years, we have found that some sizes and configurations have proven useful in a number of applications, particularly in research work, where the user has a degree of latitude in the length and diameter of the working cavity.  The vessels described below are those designs that have proved most popular over the years.

Manganin Cell Body Vessel

The “usual” workhorse is known as the Manganin Cell Body Vessel. It is a general purpose pressure vessel for up to 200,000 psi.  It is made of Aircraft Quality E-4340 alloy steel and has a single end closure, with a 12H-1 pressure port at the bottom end. The vessel has a bore that can accommodate a 1” diameter by 3” long work piece. Other standard models will accommodate pieces of up to 5 ½” or 8 3/8” long.

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Powder Bomb Vessel

Another “workhorse”- originally designed for the military for use as a powder bomb – also has a single closure. It has a nominal 2” bore and a 200cc working cavity. Its service pressure is limited to 125,000 psi. Variants on this design exist to take the working cavity up to 700cc.


This vessel is sold with a trunnion mount to allow for either horizontal or vertical operation. The trunnion has wheels to give the vessel some mobility in the laboratory.

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Geological Vessel

A third standard design was originally developed for geologists who require pressures up to 14 kilobar (200,000 psi) and temperatures of up to 1500oC in the working cavity, using inert gas as the pressure medium.


Originally, this vessel, with two closures, accommodated a furnace capable of 1500oC and a working cavity of ½” diameter by 2-½” long.  It can be used as an internally heated pressure vessel (IHPV) when paired with the furnace, or a general purpose vessel without the furnace.  Without the furnace the working cavity is 2-½” diameter with 8-½” between closures.


The top closure carries a pressure port for 200,000 psi. The bottom closure carries 4 lead thrus for power (allowing 3 zones for heating) and 4 thermocouple lead thrus (allowing the 3 thermocouples to separately monitor each of the zones).

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Custom Designed Pressure Vessels

Our process is simple: Tell us your desired parameters and we will work up a design concept, figure the costs, and provide a quotation in a timely manner.


As stated earlier, the vessels described above were standardized because those parameters were commonly requested. Modifying the end closures to fit what you need (windows, pressure ports, thermocouple ports, additional electrical ports) is often a solution. We have made many more custom designed pressure vessels over the years that we can take reference from and work into new designs.

Special Purpose Laboratory Tools

Harwood has developed tools that allow the measurement of various physical properties of different materials using lead thrus, windows and special tools designed for scientific studies.

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