Cat Pumps are an inspired choice for new land speed record

Phil Black - PII Editor 27/08/2009

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Triplex reciprocating positive displacement piston type pumps from Cat Pumps UK Limited have played a part in helping the British Steam Car Team to smash the world land speed record for a steam powered car. The world record, which had stood at 127mph since 1906, was broken by ‘Inspiration’ at the Edwards Air Force Base in California, on 25th August when the steam car reached an average speed of 139.843mph on two runs over a measured mile.

Driver Charles Burnett III piloted the car for both runs reaching a peak speed of 136.103mph on the first run and 151.085 mph on the second (Fig 1).

In order to generate the required stream pressure for a run, Inspiration’s two 70-litre hydraulic accumulator bladders, which feed the 12 onboard boilers, need to be carefully primed with demineralised water. The water is supplied from holding tanks located on two purpose-built ‘start’ and ‘turnaround’ rigs at a pressure of 40bar. This essential task was performed by to two Cat Pumps1520C triplex positive displacement plunger pumps, feeding Inspiration at a rate of between 50 and 40litres per minute (Fig.2).

The Cat Pumps have played an important role throughout the development of ‘Inspiration’, not just on the rigs but also on the test beds where the boilers have been designed. “When the car is running all the steam generated must go to the wheels so there is a lot of accumulated power onboard,” says Consulting Engineer Matthew Candy. “The design of the system means that the water must go seamlessly from the displacement to the car’s accumulator systems as is it essential to have water in the boilers at all times for if we lose the water the boiler tubes will fail very quickly. The Cat 1520C pump meets this requirement.” A significant factor for the steam car application was that the pumps were capable of handling the non-inherent lubricity properties of demineralised water.

Cat Pumps’ 1520C model is a triplex reciprocating positive displacement piston type pump and is capable of generating pressures up to 70bar. This type of pump takes in a fixed volume of liquid on each inlet stroke and physically moves it through and out of the pump with virtually no losses or inefficiencies. Cat Pumps’ triplex pumps contain three synchronised pistons or plungers which produce a low-pulsation flow that is sufficiently smooth for most applications. The flow is highly stable and predictable because the flow rate is determined almost exactly by the running speed of the pump and is virtually unaffected by back-pressure, liquid viscosity or specific gravity.

The development of ‘Inspiration’s’ boilers has taken several years, moving from an original plan of four units to a final complement of 12 units, and the1520C pump has been used on the boiler tests for all that time. “The versatility of the pump’s output enabled all testing to be undertaken with just one pump,” continues Candy. “When powered by an electric motor in the boiler test cell we found the pump easy to control and highly sensitive to the task in hand. We were able to run the flow down to as low as 4litres per minute in order to test each boiler.”

When considering the steam car development programme in its entirety, Cat Pumps’ 1520 C pumps are a relatively small component. That said their input was critical to the success of the challenge during the start-up sequence for the first run and once again before the second run. The steam could not be generated by the car’s boilers without the controlled high pressure inflow of water from the pumps and without steam at the right temperatures and pressures Inspiration’s challenge would have been a non-starter.

For further product information, contact:

Brian Hubbard
General/Sales Manager
Cat Pumps (UK) Limited
1, Fleet Business Park
Sandy Lane,
Church Crookham
FLEET, Hampshire, GU52 8BF