THE LATEST IN GULLY EMPTIERS.
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Details of a New Laffiy Machine the First Example of which has been Supplied to the Royal Borough of Kensington.
ONE OP the most successful of the A..../many gully-emptying maChines on the British market is that sold by the Laffly (England) Co., Ltd., Lensdale Road, London, N.W.6, and in its latest form many improvements over the previous model have been embodied. Reference to our illustrations will show that the weight has been very evenly distributed over the chassis frame, whilst the methods of operation and control have been simplified so that the vehicle may be easily worked by two men, the driver Oontrolling, the pump speed and valve operations for applying pressure or suction as is required to either of the two compartments of the. tank, whilst the second man deals with the emptying and resealing of the gullies.
The tank compartment into which the sludge is draWn from the street gullies has, at the rear, a large swing door, through which the load is eventually discharged, this, owing to the special method of operation on tha Laffly machine, being a matter of the utmost simplicity. When the vehicle is ready for discharging., it is backed into position at the dump and a vacuum maintained in the tank, this being sufficient to hold the ,door securely in position until everything is ready for emptying, when, by means of the special design of face valve, the vacuum is released and pressure is applied to the tank, with the consequence that the door is forced open andethe contents discharged cleanly and rapidly.
The valve control enables pressure or vacuum to be applied at will in either compartment, also it is possible to apply pressure in one compartment while suction is taking place in the other.
The lower portion of the tank normally contains a supply of fresh, clean water, which is used for resealing the street gullies to their correct level after the sludge has been withdrawn from them. This supply of water is also available under pressure, if required, for dealing with exceptionally obstinate sludge or for flushing the sewers.
One advantage of the new machine is that it is possible for the tank to be filled in three minutes by means of the pump and from any convenient source of supply.
As the class of work upon which such st vehicle is engaged is frequently carried out during the night, it is most desirable that the engine and -PurnP machinery should work quietly so that no annoyance will be caused to the resi • dents, and in the Laffly careful attention to detail has enabled this to be affected.
The upper portion of the main tank has a capacity of 500 gallons, whilst the lower one is for 600 gallons of water. A pipe connects the two and, when necessary, water may be introduced into the upper compartment, to be used in the discharging process, or for cleaning purposes. • Sight gauge glasses enable the operators to observe when either compartment is full.
The air pump has two cylinders and mounted at the near side of the chassis immediately behind the driver's seat. It is driven by a silent chain from an auxiliary shaft arranged in the gearbox and engaged by an independent lever.
The speed of the pump is controlled by a throttle so placed that it can be operated by the driver from the footpath. Indicator gauges record either vacuum Or pressure. The pipe connections to each compartment have security tanks containing a special form of ball valve which automatically cuts out the pump when either tank conipartment is over full.
It requires from 15-30 secs. to secure the neceesary degree of vacuum in the tank, after which the suction pipe is placed in the gully and the slipper valve opened, when the sludge and water are immediately sucked up into the tank.
The chassis employed for this maChine is the 5-ton type G.L.A., the power unit of which has four cylinders of 95 mm. bore and 160 mm. stroke, giving an R.A.C. rating of 22.4 h.p. It is of most modern type with overhead inlet valves mounted immediately above the exhaust valves, both being actuated by the same camshaft. The clutch, an important • member in a vehicle of this form which is constantly stopping, is of the dry plate type consisting of a single steel disc working between Ferodo rings. Two flexible joints are used for the clutch shaft.
Four forward speeds and a reverse with direct drive on top gear are provided by the gearbox. At 1,200 r.p.m. the normal speeds on the various gears are 3, 4, 8 and 13 m.p.h. A cardan shaft conveys the drive to a doublereduction rear axle of the bevel and spur type; The hand brake contracts shoes upon a transmission drum, whilst a Pedal operates rear-wheel brakes of the band type.
The wheelbase is 14 ft. 8 ins.; overall width, 7 ft. 3 ins.; height, 9 ft. 9 ins, to the top of the jib. The weight unladen is 6 tons 7 cwt. 3 qrs.