Parker Domnick Hunter

Client: Parker Domnick Hunter
Services: Stereolithography, Selective Laser Sintering, Vacuum Casting, Plastic Fabrication
Project: CBRN Filter

Project Brief

To manufacture two exhibition models of a proposed system for installation into the Trojan and Titan armoured vehicles. The display case will be representative of the final enclosure with all relevant ports etc represented.


The main larger individual components such as the manifolds, pump etc were all produced as fully finished Stereolithography models. Wherever multiple parts were required, such as the butterfly valves, elbows and connectors, we built a single SL master model and then vacuum cast parts from silicone rubber tools. Other less complex parts including the outer case were fabricated from stock sheet or tube material.


Demonstration models to be displayed at the Eurosatory International Defence Exhibition in Paris and the Farnborough Airshow 2008.

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Client Title

Case Study

Established in 1963, Parker domnick hunter is the world leading manufacturer of filtration and cold sterilisation systems for compressed air and gases. This position has been achieved by the pursuit of excellence throughout its operation. Technological innovation and export achievement have been recognised by 8 Queen’s Awards to Industry. Working closely with defence organisations, Parker domnick hunter research and development specialists ensure that every military product is developed fully for its intended use.

Since an acquisition by Parker Hannifin in 2005, Parker domnick hunter has continued development of it’s filtration technologies under the Parker umbrella.

They had previously produced a unique regenerative filtration system designed to protect personnel from chemical and biological (CW and BW) agents plus other toxic materials developed from one of the companies core technology, the pressure swing adsorption system. Parker domnick hunter’s multi absorbent system provides effective broad spectrum protection from CW and BW agents.

Regenerative CBRN technology uses two identical beds of filter media, an on-line bed of absorbent material to provide protection, while an off-line bed desorbs previously adsorbed chemicals and a purge system dispels them safely back into the externally contaminated environment. The beds reverse operation on a predetermined cycle and it is this ability to regenerate which maintains the safe integrity of the filter to provide continuous protection and safe breathing conditions for various NBC requirement platforms (vehicle, fixed building & shelter).

Parker domnick hunter’s innovative development of the regenerative filter concept culminated in the integration of a pressure and temperature swing (PTSA) system onto BAE Systems ETS program. The Trojan and Titan armoured vehicles, based on the Challenger II hull are the world’s first platforms to have a regenerative CBRN filter system fitted.

The capability of a fully regenerative CBRN filtration system has been successfully demonstrated over the past ten years, and the benefits of Parker domnick hunters’ regenerative CBRN filtration are well know:

  • Meets protection requirements for from all known CW agents AND Toxic Industrial Chemicals (TICs)
  • Regenerative – hence offers continuous protection
  • Eliminates logistical support issues
  • Environmental benefits – no disposal of filters

The next generation of this technology is currently under development and a new media is on trial. The molecular sieve hollow fibre is a semi-porous capillary like tube of adsorbent/polymer mix which is spun to form multi-layer fibres with different compositions of material in each layer.

The filters manufactured with the fibres will show significantly increased absorbent capacity and improved adsorbent kinetics. These will lead directly to a significant reduction in filter bed size/weight and power requirement. In order to house this lightweight technology, new lighter materials will be required and concepts are under development to introduce plastic housings and components as opposed to the traditional pressed and cast metal systems.

Although the system is still at a developmental stage, Parker domnick hunter were keen to demonstrate the technology and evaluate the reaction from interested parties and so the decision was made to prepare 2 full size static demonstration models to exhibit at the Eurosatory International Defence Exhibition in Paris and The Farnborough Air Show.

Paragon Rapid Technologies were already suppliers of Rapid Prototyping to Parker domnick hunter and the Parker group and so with their traditional modelmaking skills, paired up with extensive stereolithogtraphy and vacuum casting capabilities, became an obvious partner to produce the high profile concept models.

As the product was still conceptual, the design did not reflect production processes. Paragon worked along side Parker domnick hunter from an early stage, advising of appropriate processes for manufacture and solutions for assembly.

Concepts were developed for two versions, a linear design and a rotary configuration. The system essentially consists of a series of Filter Cartridges, assembled into manifolds, with pipe work etc to connect to the ancillary pumps, valves and Hepa Filters and all of this is fitted into a box as an enclosed unit.

As the models were required for display and exhibition a clear protective case was required. The case was fabricated from 8mm clear acrylic, to the design of the production enclosure, to serve the dual purpose of protecting the internal components, while being representative of the final unit including all inlets and outlets.

Paragon have a broad range of skills and experience covering the regular RP processes as well as fabrication and machining and almost all of these processes were implemented to give the most cost effective solution for the overall project.

The Manifolds and more complex components were produced in epoxy resin as Stereolithography models on Paragon’s SLA5000. Each part was meticulously finished by hand with a polished gloss finish.

Details such as Nuts and Bolts were added afterward to achieve the production look.

The filter elements were built from scratch using traditional modelmaking techniques with a painted finish. Custom graphics were produced of the Parker logo and applied prior to lacquering.

Wherever “multiple” components were required, Paragon created a master pattern, again through stereolithography before producing silicone tooling and Polyurethane vacuum castings. Many of the parts such as the Manifold Elbows, Butterfly Valves and Pipe elbows were common to both assemblies and all produced through vacuum casting.

The majority of the pipe work was fabricated from stock tubing, with unique parts such as ‘T’ pieces and ‘S’ bends produced as SL.

All of the piping was fully assembled and painted to represent a brushed Stainless Steel finish.

A standard Hepa filter supplied by Parker domnick hunter was mounted in the top of each unit and this was enclosed within a fabricated acrylic cover carefully thermo formed and bonded, offering full visibility. The Heat exchange units were also fabricated from scratch, but this time with a white painted finish.

The final models were completed and delivered on time.

Paragon Business Development Manager Darren Webb, commented “Although Paragon are at the forefront of Prototyping Technologies, it was very refreshing to have the need to call upon the more traditional skills of our model makers and to combine that with our regular processes. The whole project was very fluid, with design changes and additional components added at various stages as we were building. We were very happy with the end result and certainly look forward to producing further exhibition models”

The overall effect is very dramatic and eye catching and the models were certainly well received at the exhibitions and made it possible for the Parker engineers to explain how the concept will work. Such was the interest at the exhibitions that Parker domnick hunter are now developing the concept for manufacture, for the intended vehicle applications as well as for use with fixed building and shelter applications.

Client: Parker Domnick Hunter
Services: Stereolithography, Selective Laser Sintering, Vacuum Casting, Plastic Fabrication
Project: CBRN Filter