Combined Road-cleaning Machines for Paris.
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Big Water Wagons and Small Sweepers
are Abandoned.
Motor-driven street sweepers and waterers have given such satisfaction in Paris that arrangements are being made for the entire abolition of the horse in this department of
municipal work. A treacly the change has been made in lour of the twenty " arrondissements "or wards into which the city is divided, and the others are preparing to follow suit at an early date. In the eighth ward, which is the most fashionable quarter of the city, comprising the Avenue des ChampsElysées and the Place de l'Etoile, the work is undertaken by contract, the contractor making use of seven De Dion Bouton machines. In the three other districts using motor vehicles exclusively the work is done by the city and various types of machines are employed.
It is nearly two years since the first really serious attempt was made to employ motor vehicles for street sweeping and watering. At that time orders were placed with various manufacturers for differmt types of machines, and comparative tests were made with these. Three distinct types were put into use : light sweepers driven by a motor of riot more than 10 h.p. ; big watercarts capable of watering the widest avenue at one Operation ; and combination ma,chines capable of watering, sweeping and washing. It was found that the big water-carts had a very limited use, and could only be employed a few days a year in such wide thoroughfares as the Avenue du Bois de Boulogne. The light sweepers did good service, but they necessitated the use of horsedrawn water-carts in dry weather. The result was that the cambination machine was adopted as the most suitable for all-round service, and it is being put into use to the exclusion of the two other types.
In the eighth ward there are seven of these machines.. replacing a set of horse-drawn machines necessitating the use of from 15 to 25 horses. The number of horses necessary for this work altered COD siderably owing to their inherent variations. The lower number was sufficient in spring and autumn, and in winter and summer the full 25 were not always capable of accomplishing the work. With the seven machines in constant service and two in reserve, it is possible to undertake the whole of the work, whatever the weather conditions.
The De Dion Bouton machines have the motor in front, the rotary brush placed diagonally under the chassis:, and the water tank behind the driver's seat. The motor is an 18 h.p. model, 90 mm. by 120 mm., driving the rear wheels through a plate clutch, three-speed gearbox and transverse cardan shafts. The machines have twin rubber tires at. the rear, and single in front. The water tank has a capacity of 570 gallons. This can be used for street watering, washing, or finely spraying to prevent the raising of dust when sweeping. The earlier attempts to use motor sweepers were not very successful own-1g to the
large amount of dust that was raised. In narrow streets the water is allowed to flow out by gravity through a distributor at the rear, exactly in the same way as on the horse-drawn machmes. this is only made use of, however, in streets of such a narrow width that the front sprinklers could not be used without splashing passers-by. Most of the watering is performed through circular-section sprinklers placed at the front of the machine, slightly ahead of the dumb-irons.
The centrifugal water pump mounted on a, sub-frame at the extreme rear of the chassis is driven by a, propeller shaft having a sliding pinion on its forward end, which is brought into engagement with one of the gear-set pinions. With the pump working, the water flows to a distributing chamber communicating with left, and right-hand feed pipes. In this chamber there are two piston valves, so that it is possible to give passage to either one or the other pipe, or to both, as desired. At the forward end of each main feed pipe is another piston vaI e which is opened when it is desired to use the front sprinklers. These four valves are controlled by four levers on the dashboard immediately in front of the driver. For street watering the four valves are left fully open. and control is by
means of semi-circular guards fitting around the semi circular. sprayers and covering or uncovering to a greater or lesser degree the holes through which the water is sprayed. This gives a very quick control and enables the driver instantly to stop the flow when in danger of splashing foot passengers. On the main feed pipes are two by-passes, with outlets just ahead of the brushes, to be used for street washing. The outlet being very near the ground, a very strong force of water can be directed on to the surface of the street. Either one or both of these washers can be used, as desired. Finally there is a very fine sprayer just in front of the brush, which is brought into use when sweeping in dry weather. This effectively prevents the raising of dust.
The machines run normally at a speed of 74 miles an hour. When washing, with both outlets at work. the tank is emptied in about 10 minutes. For street watering with the front sprinklers at full capacity the supply of water lasts about 15 minutes. during which time the machine will have covered two miles and will have watered a surface 50
ft. in width. With the central sprayer only in use, the supply of water is sufficient for four or five hours.
Each machine works 10 hours a day, the driver going on duty at 4 a.m.. having a two-hours rest in the middle of the day, and finishing his work at 4 p.m. The average daily mileage of each machine varies from 38 to 45, this being based on the full fleet of seven machines working over a period of three months. Benzole is used as fuel because of its lower price compared with petrol. It necessitates a more frequent cleaning of the motor and grinding of valves, but its lower price compensates for this extra labour. The amount of benzoic used is 46 gallons per day for the fleet of seven machines ; estimating on 40 miles per day per machine, this gives a consumption at the rate of 10.7 miles to the gallon.
According to the Paris authorities, the economy resulting from the use of motor sweepers in place of horse-drawn machines is from 12 to 14 per cent. There is the advantage, too, that the motor vehicles, having a higher speed, do not interfere with the normal flow of traffic. At Versailles, which has also a. complete motor street-sweeping service, the economy is 50 per cent. compared with the use of horses. The old Royal city has the advantage, however, of possessing unusually wide avenues and very little traffic, thus allowing the motor machines to work at their highest efficiency. Under the crowded conditions prevailing in Paris. it is impossible for the machines to work at their best efficlieney except in the early morning.