Fig. 94.—Revolving Sprinkler (Burn and Brown’s patent).
Messrs. Burn Bros. manufacture a revolving sprinkler, “Burn and Brown’s Patent,” shown in [Fig. 94], which has one or two special features. These consist of a self-regulating apparatus for dealing with the variation of the flow of sewage and at the same time cleaning the orifices. A shaft carried on each of the arms, and mounted on suitable bearings, is provided with tapered fingers fixed in a position corresponding to the holes in the arms. By means of a float in the circular revolving tank connected to a simple lever the shafts on the arms are given a slight movement, which causes the fingers to enter the orifices in the arms as the flow decreases, and to be withdrawn as the flow increases. The result is that the orifices are enlarged or reduced as the flow varies, and the movement of the tapered fingers tends to make the orifices self-cleansing. It is claimed for this distributor, that it can be made to deal with any variation in flow of sewage up to 6 volumes, with a maximum head of less than 18 inches above the surface of the material of the filter.
A new type of automatic revolving sprinkler is the “Hodgson” overflow type, manufactured by Messrs. George Kent, Ltd. As will be seen from the illustration, [Fig. 95], the sewage passes first into a feed chamber attached to the central column, from which it flows into the distributing chamber D, to which the arms are attached. It is claimed that by use of the weirs W in the distributing chamber, a uniform speed of rotation and consequently a uniform distribution, is secured. The ball-bearing upon which the rotating portion is carried is stated to take both the side and end friction.
The revolving distributors previously described are all constructed on the Barker’s Mill principle, to some extent if not entirely. The Fiddian type of distributor, supplied by Messrs. Birch Killon and Co., and illustrated [Fig. 96], is based upon an entirely different principle. It consists of an elongated water-wheel, which revolves around a circular filter. It is pivoted at the centre of the filter upon the supply pipe, and the outer end of the distributor is carried upon a rail track. In the case of large filters, from 70 feet to 110 feet diameter, two rail tracks are used. The liquid passes through the supply pipe and is delivered into the buckets of the water-wheel, from which it falls in the form of a film, so that the water-wheel not only drives itself over the filter by means of the weight of the liquid, but it also distributes the liquid which drives it. A very small quantity is sufficient to start the distributor and keep it in motion, the head required, measured from the surface of the filter, being about 18 inches. The buckets are provided with graduated weirs, the width of which is proportionate to its distance from the centre of the filter. By this means uniformity of distribution is secured. It is claimed that as there are no small holes to be choked, the apparatus can be employed for all kinds of liquid with the minimum of attention, and that it does not require any dosing apparatus.
Fig. 95.—“Hodgson” Revolving Sprinkler.