Pumps and circumstances
Published: 01 January, 2007
In the early 1970s the UK fire brigades came together and set down a standard for a portable fire pump that would deliver the flow and pressures needed for fire fighting and flood control.
Known as JCDD/30 the standard called for either 80 gallons/minute, Type 1, or 250 gallons/minute, Type 2, at pressures of 80 and 100 lb/in_ respectively (363 l/min @ 5.5 bar and 1,137 l/min @ 6.9 bar). Engines were to be 4-stroke petrol, multi
cylinder (although single cylinder 2 stroke were allowed for the smaller Type 1 pumps). A maximum weight limit of 275 lbs (125 kg) was imposed as the unit had be capable of being carried by two people - a tough target for pumps of the time.
From the late 70s onwards the JCDD specification Type 2 pumps became the mainstay of the UK Fire Service and because many brigades in British export markets followed the UK lead, Type 2 pumps generated a healthy export market for British manufacturers.
Angus Fire responded to the challenge and produced a Type 2 pump with a lightweight 4 cylinder 4 stroke petrol engine using a revolutionary aluminium block and cylinder head to meet the weight target. Know as the Angus LW1200 (later developed into the LW1300) the pump became the mainstay of the portable pump range for over two decades. Smaller, lighter pumps:
Like most industries the needs of the brigades, in both the UK and Europe have changed. By the late 1990s weight and space on brigade vehicles was at a premium. In addition brigades had to take account of changes imposed by health and safety legislation. Large portable pumps, weighing up to 125 kg, could no longer be carried safely by two people and the locker space taken up by the traditional JCDD/30 pump was at a premium as a greater range of equipment vied for space on vehicles.
From 2000 onwards a range of smaller, light weight pumps using air cooled engines was developed. Both the LW500 and LW800 (550 l/min and 800 l/min @ 7 bar) use Briggs & Stratton “V” twin, aluminium block and head, air cooled engines derived from, light, yet robust and proven industrial units.
Not only were these pumps light weight but they took up just over half the locker space of the old JCDD/30 pumps.
In 2005 the supply of lightweight alloy engines suitable for use in fire pumps ceased. While pump manufacturers had, in the past, been able to adapt car engines with their electronic environmental controls and engine management systems, are not easily adapted for use in portable pumps and car manufacturers are reluctant to supply non standard engines in small quantities.
As a result the range was extended using “V” twin air cooled engines and are developing a new range of pumps based on 3 cylinder industrial engines.
Parallel with the move to smaller and lighter petrol pumps the demand for portable diesel pumps has increased. Applications where the fire risk from a spark-ignition engine are unacceptable, demand a diesel pump. To meet this need a range of diesel pumps introducing new air and water-cooled models was developed.
The direction of future developments:
Radical developments in pump design are unlikely. The concept of a simple single stage centrifugal pump directly coupled to an air cooled industrial based engine has proven popular with brigades around the world.
As a result, current developments are mostly directed at reducing weight and increasing reliability. Air-cooled pumps based on lightweight alloy industrial engines have been shown to provided reliable package up to and including 45 hp (34kW).
Above this power air-cooling is not easily available and in hot climates can become unreliable. Water-cooled multi cylinder engines prove popular even though they are heavier with their indirect water cooling systems and safety devices to stop engines overheating if the water supply is suspended.
Development has been channelled into reducing the number of parts which both reduces weight and improves reliability. All the smaller air-cooled pumps mount the impeller directly on to the engine crankshaft eliminating the need for intermediate bearings. All these pumps use exhaust eject priming - a system which requires no moving parts.
Maintenance is always at the forefront of each new design. Simplicity of design and ease of access make all these pumps easy to maintain. All air-cooled models use a ‘Gell-Cell’ battery. Unlike conventional batteries with a liquid electrolyte the Gell-Cell uses a gel electrolyte. Not only does the gel improve the starting performance of the battery but it is resistant to
vibration and tilting during transit and can even be started upside down!
The latest in the range of air-cooled pumps, the LWA1200, incorporates a carbon fibre undertray to reinforce the stainless steel outer frame, saving weight and improving rigidity. In addition, the fibreglass fuel tank slides out on stainless steel rails, enabling it to be filled while the engine is running. Future developments aim to reduce noise levels to meet EEC legislation and ensure compliance with current emission regulations essential for many fire service users in Europe. A dual strategy for the future as far as pumps is concerned must be to focus on reliability and easy maintenance and provide a range of petrol and diesel models to provide performance at a weight and size demanded by modern firefighting vehicles.