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The Makers' Angle on

24th May 1935, Page 54
24th May 1935
Page 54
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FIRE-FIGHTING PROGRESS

The Experiences of Leading Manufacturers Provide an Illuminating Sidelight on the Different Aspects of Fire Fighting

Dennis Brothers' Lengthy Fire-engine Connection.

FOR many years the Braidwood type of body has been familiar in firefighting circles and, until recent years, it has been unchallenged. Dennis Brothers, Ltd., of Guildford, points out that, at the present time, there are two rivals to this design. There is the New World pattern, in which the personnel are carried on longitudinal seats facing inwards to a central gangway, thereby providing greater safety and improved weather protection. The limousine type of totally enclosed appliance has much to recommend it on the score of appearance,

but it has called for much ingenuity on the part of manufacturers to arrange for the compact and accessible stowage of gear and unimpeded entrance and exit. Another idea in body styles is a modification of the 13raidwood type, in which a second transverse seat is placed behind the driver's seat.

One of the earliest types of Dennis fire-engine was delivered in 1908 to the Bradford authorities and it was one of the first to be successfully equipped with a turbine-type pump. The following year, eight Dennis fire-engines were produced, two of them for the Kingston-on-Thames Brigade, and these are still in active service. Last year, after 25 years in commission, they were returned to the works for overhaul.

Some recently delivered Dennis appliances afford an indication of the different types that the company is building at the present time. The inside-type body is exemplified in the case of a special " Light 6 " model, just commissioned by the Leeds Brigade. By reason of a high power-to-weight ratio, this machine has a remarkable road performance, which renders it eminently suitable as a first-call appliance. The six-cylindered overhead-camshaft engine develops 100 b.h.p, and enables the appliance which, with crew and full equipment, weighs under 5 tons, to accelerate from 10 to 30 m.p.h. in top gear in 17 B36 seconds, to climb gradients of 1 in 41 in second gear and to achieve a top speed in excess of 65 m.p.h. Although the pump is centrally located at the rear, it offers no obstruction to the men when mounting or dismounting, owing to its low position.

This pump, as is the case with all Dennis fire-engines, is of the highpressure multi-stage turbine type, notably compact and, on account of its construction in gunmetal, particularly light in weight. The pumping capacity of this appliance is 400 g.p.m. at 200 lb. pressure.

London's latest fire-engine, which is illustrated on page 499 of this issue, affords a further example of Dennis fire-fighting products. This appliance, built to the design of Major C. C. B. Morris, the Chief Officer, is based upon the standard Dennis 80 b.h.p. model, with a pump at the rear and suction hose accommodated in two tunnels running below the body, which is of streamline pattern and gives accommodation to-six men on two transverse seats.

It is of interest to recall that 230 Dennis fire-engines have now been supplied to the London Fire Brigade.

An example of the open-type body. with two transverse seats for the crew, will be on view at the Scarborough Conference of the Professional Fire Brigades Association. This machine is equipped with a six-cylindered engine and has a delivery output of 650-800 g.p.m., but it is unusual in that it has the pump situated in line with the driver's seat, the suction inlet and delivery outlets being carried to both sides.

Trends Revealed by Leyland's Experience.

D-II/RING the past two or three years Leyland Motors, Ltd., Leyland, Lanes, has supplied a number of fireengines to brigades in this country, and an examination, therefore, of the type of machine which is being produced gives a good indication of the presentday trend in design.

An outstanding feature is the demand for the smaller type of engine with ,a pump having a capacity of about 400 g.p.m. An appliance of this size is of value in-'offering complete protection for rural areas and it is a suitable machine for first turn-outs for

the larger municipal brigades. The more limited demand for the bigger pump of about 700 g.p.m. remains steady. The turntable escape of a length up to about 100 ft. is also coming to the fore.

Improvements in design are diseernible in both chassis and bady. For instance, in the Leyland 400gallon-capacity outfit, a new pump, which gives a much higher efficiency than the older type, has recently been fitted and its improved performance is particularly evident when depth-lift conditions are called for and when it is necessary to pump through long lines

of hose. The pump is lighter in weight And is practically vibrationless in operation. A feature of the design is the patented single gland, which demands the minimum of attention and is provided with a spring-loaded ad justment of 1 in Vi henthis adjusiment has been. taken up, it is a simple Matter to repack the gland, which can be done while the pump is running.

Another innovation has been the cubstitution of the Leyland torque converter for the conventional form of transmission on several fire tenders, and the quicker acceleration which is given is a valuable asset.

On the bodywork side; there is a gradual tendency to discontinue the use of the type on which the personnel sit sideways, and a number of bodies of the New World type has been specified, as well as those patterns which permit the use of two transverse seats, either enclosed, or exposed.

The greatest change in turntableescape 'equipment has been the substitution of steel escapes for woOd apparatus, with the result that a demand for longer escapes has been experienced; all-steel escapes up to 132 ft. in length have been called for. One advantage of this construction is the facility with which inspection can be • carried out, and it is almost impossible for corrosion to OMIT unseen.

Merryweather's Part in Fire-engine Progress.

• DURING more than a quarter of a I./century, Merryweatheaand Sons, Ltd., the well-known concern of fire engineers, of Greenwich Road, London, S.E.10, has had uniqut. experience in the construction of motor fire-engines and fire escapes and has been responsible for much pioneer work in fire-fighting. After building manual and horse-drawn steam fire-engines formany years, the company achieved a notable advance when, in 1899, it produced the first motor (steam) fire. engine and, later, in 1903, when it constructed a petrol fire-engine (a chemical engine and escape), which was supplied to the Tottenham authorities.

A year later, many fire-fighting ideas were destined to be revised following the introduction of the motor fire pump. Equipped with the famous

Hatfield pump, machines of this type are still being supplied to fire brigades in all parts of the world. In the same year the Merryweather concern built a combination" machine, equipped with a fire pump, chemical engine and fire escape, for the Finchley Brigade; it is shown in one of the accompanying illustrations. A centrifugal pump was brought out in 1906, and machines.' fitted with the latest Merryweather '2povverful turbine pump have been supplied to the London Fire Brigade and to other important brigades at home and abroad.

Simultaneously with the production of powerful fire-pumping equipment, the company designed and constructed, in 1908, a motor turntable ladder on the "one-engine" principle, the power of the petrol unit being employed to actuate the ladder mechanism. The company also showed enterprise in adapting the motorcycle to the needs of the fire service by building a sidecar outfit with first-aid fire appliances ; that was in 1910.

, During the war period, in addition to other activities, the concern received official contracts for a number of fire-engines with pumping capacities of 1,000 g.p.m. In 1921, the Merryweather company produced a trailer fire pump, with the object of meeting the difficulties experienced by fire brigades faced with the task of protecting rural areas, work which often involved the negotiation of soft ground and narrow gateways.

The following year the company Vupplied its first fire-engine on priminatic tyres and, in 1924, a "Fire Suds ' 'tender for dealing with oil fires was built, this machine being used at the British Empire Exhibition and subsequently acquired by the Leeds Fire Brigade.

Another important advance was the construction of a motor turntable ladder with a powerful fire pump on the same chassis ; a Merryweather machine of this type was, supplied to Leicester in 1927. A fire-engine which the company produced in 1930 had a twospeed gear pump drive, by means of which the pump would deliver 230 g.p.m. at 165 lb. pressure, or 390 g.p.m. at 98 lb. pressure.

An outstanding milestone in firefighting history was marked in 1931, when the Edinnurgh authorities were supplied with a saloon-type fire-engine, which had an enclosed body, powerful pump, first-aid apparatus and ladder. The company, claims to have constructed the first all-British turntable fire escape with a ladder built entirely of steel, and such machines have been supplied to fire brigades at home and abroad, a recent delivery—to Edinburgh—having a 105-ft. ladder.

During last year the Merryweather concern supplied a streamlined fireengine to the Lancaster Brigade, this laving an enclosed body of shapely design and a 275 g.p.m. pump.

In addition to the numerous types of motor appliance built by the company, it introduced Superlurnin for fire fittings, this being a light metal alloy, si38 which is claimed to be as durable as gunmetal, but is only one-third • its weight, Karbono (carbonic-acid gas) extinguishers for fires precluding the use of water and the patent " Xaustsuds " generator.

Halley's Comments on the Trend in

Design.

THAT the past few years show remarkable progress in British firefighting equipment, enabling the fire services to strike quicklx and powerfully at outbreaks of fire, is the opinion of Halley Motors, Ltd., Glasgow. There is a general trend towards greater protection and comfort for the personnel which is marked by the improved types of body.

The company says that the advance in chassis and engine design has been identical with that shown in other spheres, but it is somewhat surprising that the oil engine shows no tendency as yet to replace the petrol unit, al'though the former has proved to be quick at getting away, has great power and 'flexibility, and, in itself, does not constitute stich a great fire hazard.

Until recently much more attention has been given to promptitude in

getting the pump to the centre of a fire than to the essential point of getting water to the pump. In districts plenteously supplied with hydrants fed with a good pressure this matter may appear to be of secondary importance, but where deep lifts, long suctions, Or shallow supplies only aro available, these conditions indicate generally the lines on which pump development is to be expected.

Greater attention is being paid to pump design, so that its characteristics combine with those of the engine to give the best hydraulic efficiency under all conditions, and that no limit is imposed on the pump speed by the exhauster when picking .up its water. Exha.usters of the reciprocating type with limiting speeds and many moving parts are, the company points out, giving place to the sell-priming rotary type, which is capable of continuous operation at all pump speeds, and automatically takes charge of air leaks or faulty suction joints.

Foolproof automatic priming to depths of 30 ft. at 1 ft. per second, and 25 ft. at 2 ft. per second, is now possible. These pumps maintain their full output with varying suction Efts pp to 241t.


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