es raise it to the
first of a series of high level covered service reservoirs.
In the filter press there are 20 hollow disks representing a filtering
area of 250 square feet, or a total of 3,250 square feet. The water to
be filtered passes into the body of the filter and then through a
filtering medium of cloth laid on a thin perforated zinc plate, into
the inner side of the disks, from whence it is conveyed through the
hollow shaft, to which the disks are attached, to the high level
pumps.
The filter cloths are cleaned three times every 24 hours, without
removal, by jets of softened water from the main, having a pressure of
60 pounds to the square inch. During cleaning operations the disks are
made to revolve slowly; this only occupies a space of five minutes for
each cleaning. The cloths last from six to eight months without being
renewed. They also occasionally use for further cleaning the cloths a
jet of steam injected upon the center of the disks in order to remove
by partial boiling the insoluble particles engrained in the cloths.
This has been found to make the cloths last longer. This cloth is
obtained from Porritt Bros. and Austen, Stubbing Vale, Ramsbottom, and
costs 131/2d. per lineal yard of a width to suit the disks.
The quantity softened is 21/4 million gallons per 24 hours, but the
present plant can deal with 21/2 million gallons, and the buildings are
erected for 31/2 million gallons, additional filters and lime producing
tanks being only required to deal with the increased quantity. The
costs of the softening works was L10,394, of which L7,844 was for the
softening machinery and plant and L2,550 for the reservoir, buildings,
etc.
The working expenses, including lime, labor, cloths, general repairs,
and steam, is stated to be 0.225d. per 1,000 gallons, the labor
required being only two men, one on the day and the other on the night
shift, with an occasional man to assist.
The hardness of the Southampton water on Clark's scale is 18 deg. of total
hardness, and this is reduced down to 6 deg. or 8 deg. by this process.--_Chem.
Tr. Jour._
* * * * *
A NEW LABORATORY PROCESS FOR PREPARING HYDROBROMIC ACID.
By G.S. NEWTH.
This method is a synthetical one, and consists in passing a stream of
hydrogen and bromine vapor over a spiral of platinum wire heated to
bright redness by means of an electric current. A glass tube, about 7
inches long and 5/8 of an
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